"""
SQLAlchemy models for Compliance & Audit Framework.

Tables:
- compliance_regulations: EU regulations, directives, BSI standards
- compliance_requirements: Individual requirements from regulations
- compliance_controls: Technical & organizational controls
- compliance_control_mappings: Requirement <-> Control mappings
- compliance_evidence: Audit evidence (files, reports, configs)
- compliance_risks: Risk register with likelihood x impact
- compliance_audit_exports: Export history for auditors
"""

import enum
import uuid
from datetime import datetime, date
from typing import Optional, List

from sqlalchemy import (
    Column, String, Text, Integer, Boolean, DateTime, Date,
    ForeignKey, Enum, JSON, Index, Float
)
from sqlalchemy.orm import relationship

# Import shared Base from classroom_engine
from classroom_engine.database import Base


# ============================================================================
# ENUMS
# ============================================================================

class RegulationTypeEnum(str, enum.Enum):
    """Type of regulation/standard."""
    EU_REGULATION = "eu_regulation"      # Directly applicable EU law
    EU_DIRECTIVE = "eu_directive"        # Requires national implementation
    DE_LAW = "de_law"                    # German national law
    BSI_STANDARD = "bsi_standard"        # BSI technical guidelines
    INDUSTRY_STANDARD = "industry_standard"  # ISO, OWASP, etc.


class ControlTypeEnum(str, enum.Enum):
    """Type of security control."""
    PREVENTIVE = "preventive"    # Prevents incidents
    DETECTIVE = "detective"      # Detects incidents
    CORRECTIVE = "corrective"    # Corrects after incidents


class ControlDomainEnum(str, enum.Enum):
    """Domain/category of control."""
    GOVERNANCE = "gov"           # Governance & Organization
    PRIVACY = "priv"             # Privacy & Data Protection
    IAM = "iam"                  # Identity & Access Management
    CRYPTO = "crypto"            # Cryptography & Key Management
    SDLC = "sdlc"                # Secure Development Lifecycle
    OPS = "ops"                  # Operations & Monitoring
    AI = "ai"                    # AI-specific controls
    CRA = "cra"                  # CRA & Supply Chain
    AUDIT = "aud"                # Audit & Traceability


class ControlStatusEnum(str, enum.Enum):
    """Implementation status of a control."""
    PASS = "pass"                # Fully implemented & passing
    PARTIAL = "partial"          # Partially implemented
    FAIL = "fail"                # Not passing
    NOT_APPLICABLE = "n/a"       # Not applicable
    PLANNED = "planned"          # Planned for implementation


class RiskLevelEnum(str, enum.Enum):
    """Risk severity level."""
    LOW = "low"
    MEDIUM = "medium"
    HIGH = "high"
    CRITICAL = "critical"


class EvidenceStatusEnum(str, enum.Enum):
    """Status of evidence artifact."""
    VALID = "valid"              # Currently valid
    EXPIRED = "expired"          # Past validity date
    PENDING = "pending"          # Awaiting validation
    FAILED = "failed"            # Failed validation


class ExportStatusEnum(str, enum.Enum):
    """Status of audit export."""
    PENDING = "pending"
    GENERATING = "generating"
    COMPLETED = "completed"
    FAILED = "failed"


class ServiceTypeEnum(str, enum.Enum):
    """Type of Breakpilot service/module."""
    BACKEND = "backend"           # API/Backend services
    DATABASE = "database"         # Data storage
    AI = "ai"                     # AI/ML services
    COMMUNICATION = "communication"  # Chat/Video/Messaging
    STORAGE = "storage"           # File/Object storage
    INFRASTRUCTURE = "infrastructure"  # Load balancer, reverse proxy
    MONITORING = "monitoring"     # Logging, metrics
    SECURITY = "security"         # Auth, encryption, secrets


class RelevanceLevelEnum(str, enum.Enum):
    """Relevance level of a regulation to a service."""
    CRITICAL = "critical"         # Non-compliance = shutdown
    HIGH = "high"                 # Major risk
    MEDIUM = "medium"             # Moderate risk
    LOW = "low"                   # Minor risk


# ============================================================================
# MODELS
# ============================================================================

class RegulationDB(Base):
    """
    Represents a regulation, directive, or standard.

    Examples: GDPR, AI Act, CRA, BSI-TR-03161
    """
    __tablename__ = 'compliance_regulations'

    id = Column(String(36), primary_key=True, default=lambda: str(uuid.uuid4()))
    code = Column(String(20), unique=True, nullable=False, index=True)  # e.g., "GDPR", "AIACT"
    name = Column(String(200), nullable=False)                           # Short name
    full_name = Column(Text)                                             # Full official name
    regulation_type = Column(Enum(RegulationTypeEnum), nullable=False)
    source_url = Column(String(500))                                     # EUR-Lex URL or similar
    local_pdf_path = Column(String(500))                                 # Local PDF if available
    effective_date = Column(Date)                                        # When it came into force
    description = Column(Text)                                           # Brief description
    is_active = Column(Boolean, default=True)

    # Timestamps
    created_at = Column(DateTime, default=datetime.utcnow)
    updated_at = Column(DateTime, default=datetime.utcnow, onupdate=datetime.utcnow)

    # Relationships
    requirements = relationship("RequirementDB", back_populates="regulation", cascade="all, delete-orphan")

    def __repr__(self):
        return f"<Regulation {self.code}: {self.name}>"


class RequirementDB(Base):
    """
    Individual requirement from a regulation.

    Examples: GDPR Art. 32(1)(a), AI Act Art. 9, BSI-TR O.Auth_1
    """
    __tablename__ = 'compliance_requirements'

    id = Column(String(36), primary_key=True, default=lambda: str(uuid.uuid4()))
    regulation_id = Column(String(36), ForeignKey('compliance_regulations.id'), nullable=False, index=True)

    # Requirement identification
    article = Column(String(50), nullable=False)                         # e.g., "Art. 32", "O.Auth_1"
    paragraph = Column(String(20))                                       # e.g., "(1)(a)"
    requirement_id_external = Column(String(50))                         # External ID (e.g., BSI ID)
    title = Column(String(300), nullable=False)                          # Requirement title
    description = Column(Text)                                           # Brief description
    requirement_text = Column(Text)                                      # Original text from regulation

    # Breakpilot-specific interpretation and implementation
    breakpilot_interpretation = Column(Text)                             # How Breakpilot interprets this
    implementation_status = Column(String(30), default="not_started")    # not_started, in_progress, implemented, verified
    implementation_details = Column(Text)                                # How we implemented it
    code_references = Column(JSON)                                       # List of {"file": "...", "line": ..., "description": "..."}
    documentation_links = Column(JSON)                                   # List of internal doc links

    # Evidence for auditors
    evidence_description = Column(Text)                                  # What evidence proves compliance
    evidence_artifacts = Column(JSON)                                    # List of {"type": "...", "path": "...", "description": "..."}

    # Audit-specific fields
    auditor_notes = Column(Text)                                         # Notes from auditor review
    audit_status = Column(String(30), default="pending")                 # pending, in_review, approved, rejected
    last_audit_date = Column(DateTime)
    last_auditor = Column(String(100))

    is_applicable = Column(Boolean, default=True)                        # Applicable to Breakpilot?
    applicability_reason = Column(Text)                                  # Why/why not applicable

    priority = Column(Integer, default=2)                                # 1=Critical, 2=High, 3=Medium

    # Source document reference
    source_page = Column(Integer)                                        # Page number in source document
    source_section = Column(String(100))                                 # Section in source document

    # Timestamps
    created_at = Column(DateTime, default=datetime.utcnow)
    updated_at = Column(DateTime, default=datetime.utcnow, onupdate=datetime.utcnow)

    # Relationships
    regulation = relationship("RegulationDB", back_populates="requirements")
    control_mappings = relationship("ControlMappingDB", back_populates="requirement", cascade="all, delete-orphan")

    __table_args__ = (
        Index('ix_requirement_regulation_article', 'regulation_id', 'article'),
        Index('ix_requirement_audit_status', 'audit_status'),
        Index('ix_requirement_impl_status', 'implementation_status'),
    )

    def __repr__(self):
        return f"<Requirement {self.article} {self.paragraph or ''}>"


class ControlDB(Base):
    """
    Technical or organizational security control.

    Examples: PRIV-001 (Verarbeitungsverzeichnis), SDLC-001 (SAST Scanning)
    """
    __tablename__ = 'compliance_controls'

    id = Column(String(36), primary_key=True, default=lambda: str(uuid.uuid4()))
    control_id = Column(String(20), unique=True, nullable=False, index=True)  # e.g., "PRIV-001"

    domain = Column(Enum(ControlDomainEnum), nullable=False, index=True)
    control_type = Column(Enum(ControlTypeEnum), nullable=False)

    title = Column(String(300), nullable=False)
    description = Column(Text)
    pass_criteria = Column(Text, nullable=False)                         # Measurable pass criteria
    implementation_guidance = Column(Text)                               # How to implement

    # Code/Evidence references
    code_reference = Column(String(500))                                 # e.g., "backend/middleware/pii_redactor.py:45"
    documentation_url = Column(String(500))                              # Link to internal docs

    # Automation
    is_automated = Column(Boolean, default=False)
    automation_tool = Column(String(100))                                # e.g., "Semgrep", "Trivy"
    automation_config = Column(JSON)                                     # Tool-specific config

    # Status
    status = Column(Enum(ControlStatusEnum), default=ControlStatusEnum.PLANNED)
    status_notes = Column(Text)

    # Ownership & Review
    owner = Column(String(100))                                          # Responsible person/team
    review_frequency_days = Column(Integer, default=90)
    last_reviewed_at = Column(DateTime)
    next_review_at = Column(DateTime)

    # Timestamps
    created_at = Column(DateTime, default=datetime.utcnow)
    updated_at = Column(DateTime, default=datetime.utcnow, onupdate=datetime.utcnow)

    # Relationships
    mappings = relationship("ControlMappingDB", back_populates="control", cascade="all, delete-orphan")
    evidence = relationship("EvidenceDB", back_populates="control", cascade="all, delete-orphan")

    __table_args__ = (
        Index('ix_control_domain_status', 'domain', 'status'),
    )

    def __repr__(self):
        return f"<Control {self.control_id}: {self.title}>"


class ControlMappingDB(Base):
    """
    Maps requirements to controls (many-to-many with metadata).
    """
    __tablename__ = 'compliance_control_mappings'

    id = Column(String(36), primary_key=True, default=lambda: str(uuid.uuid4()))
    requirement_id = Column(String(36), ForeignKey('compliance_requirements.id'), nullable=False, index=True)
    control_id = Column(String(36), ForeignKey('compliance_controls.id'), nullable=False, index=True)

    coverage_level = Column(String(20), default="full")                  # "full", "partial", "planned"
    notes = Column(Text)                                                 # Explanation of coverage

    # Timestamps
    created_at = Column(DateTime, default=datetime.utcnow)
    updated_at = Column(DateTime, default=datetime.utcnow, onupdate=datetime.utcnow)

    # Relationships
    requirement = relationship("RequirementDB", back_populates="control_mappings")
    control = relationship("ControlDB", back_populates="mappings")

    __table_args__ = (
        Index('ix_mapping_req_ctrl', 'requirement_id', 'control_id', unique=True),
    )


class EvidenceDB(Base):
    """
    Audit evidence for controls.

    Types: scan_report, policy_document, config_snapshot, test_result,
           manual_upload, screenshot, external_link
    """
    __tablename__ = 'compliance_evidence'

    id = Column(String(36), primary_key=True, default=lambda: str(uuid.uuid4()))
    control_id = Column(String(36), ForeignKey('compliance_controls.id'), nullable=False, index=True)

    evidence_type = Column(String(50), nullable=False)                   # Type of evidence
    title = Column(String(300), nullable=False)
    description = Column(Text)

    # File/Link storage
    artifact_path = Column(String(500))                                  # Local file path
    artifact_url = Column(String(500))                                   # External URL
    artifact_hash = Column(String(64))                                   # SHA-256 hash
    file_size_bytes = Column(Integer)
    mime_type = Column(String(100))

    # Validity period
    valid_from = Column(DateTime, nullable=False, default=datetime.utcnow)
    valid_until = Column(DateTime)                                       # NULL = no expiry
    status = Column(Enum(EvidenceStatusEnum), default=EvidenceStatusEnum.VALID)

    # Source tracking
    source = Column(String(100))                                         # "ci_pipeline", "manual", "api"
    ci_job_id = Column(String(100))                                      # CI/CD job reference
    uploaded_by = Column(String(100))                                    # User who uploaded

    # Timestamps
    collected_at = Column(DateTime, default=datetime.utcnow)
    created_at = Column(DateTime, default=datetime.utcnow)
    updated_at = Column(DateTime, default=datetime.utcnow, onupdate=datetime.utcnow)

    # Relationships
    control = relationship("ControlDB", back_populates="evidence")

    __table_args__ = (
        Index('ix_evidence_control_type', 'control_id', 'evidence_type'),
        Index('ix_evidence_status', 'status'),
    )

    def __repr__(self):
        return f"<Evidence {self.evidence_type}: {self.title}>"


class RiskDB(Base):
    """
    Risk register entry with likelihood x impact scoring.
    """
    __tablename__ = 'compliance_risks'

    id = Column(String(36), primary_key=True, default=lambda: str(uuid.uuid4()))
    risk_id = Column(String(20), unique=True, nullable=False, index=True)  # e.g., "RISK-001"

    title = Column(String(300), nullable=False)
    description = Column(Text)
    category = Column(String(50), nullable=False)                        # "data_breach", "compliance_gap", etc.

    # Inherent risk (before controls)
    likelihood = Column(Integer, nullable=False)                         # 1-5
    impact = Column(Integer, nullable=False)                             # 1-5
    inherent_risk = Column(Enum(RiskLevelEnum), nullable=False)

    # Mitigating controls
    mitigating_controls = Column(JSON)                                   # List of control_ids

    # Residual risk (after controls)
    residual_likelihood = Column(Integer)
    residual_impact = Column(Integer)
    residual_risk = Column(Enum(RiskLevelEnum))

    # Management
    owner = Column(String(100))
    status = Column(String(20), default="open")                          # "open", "mitigated", "accepted", "transferred"
    treatment_plan = Column(Text)

    # Review
    identified_date = Column(Date, default=date.today)
    review_date = Column(Date)
    last_assessed_at = Column(DateTime)

    # Timestamps
    created_at = Column(DateTime, default=datetime.utcnow)
    updated_at = Column(DateTime, default=datetime.utcnow, onupdate=datetime.utcnow)

    __table_args__ = (
        Index('ix_risk_category_status', 'category', 'status'),
        Index('ix_risk_inherent', 'inherent_risk'),
    )

    def __repr__(self):
        return f"<Risk {self.risk_id}: {self.title}>"

    @staticmethod
    def calculate_risk_level(likelihood: int, impact: int) -> RiskLevelEnum:
        """Calculate risk level from likelihood x impact matrix."""
        score = likelihood * impact
        if score >= 20:
            return RiskLevelEnum.CRITICAL
        elif score >= 12:
            return RiskLevelEnum.HIGH
        elif score >= 6:
            return RiskLevelEnum.MEDIUM
        else:
            return RiskLevelEnum.LOW


class AIClassificationEnum(str, enum.Enum):
    """AI Act risk classification."""
    PROHIBITED = "prohibited"
    HIGH_RISK = "high-risk"
    LIMITED_RISK = "limited-risk"
    MINIMAL_RISK = "minimal-risk"
    UNCLASSIFIED = "unclassified"


class AISystemStatusEnum(str, enum.Enum):
    """Status of an AI system in compliance tracking."""
    DRAFT = "draft"
    CLASSIFIED = "classified"
    COMPLIANT = "compliant"
    NON_COMPLIANT = "non-compliant"


class AISystemDB(Base):
    """
    AI System registry for AI Act compliance.
    Tracks AI systems, their risk classification, and compliance status.
    """
    __tablename__ = 'compliance_ai_systems'

    id = Column(String(36), primary_key=True, default=lambda: str(uuid.uuid4()))
    name = Column(String(300), nullable=False)
    description = Column(Text)
    purpose = Column(String(500))
    sector = Column(String(100))

    # AI Act classification
    classification = Column(Enum(AIClassificationEnum), default=AIClassificationEnum.UNCLASSIFIED)
    status = Column(Enum(AISystemStatusEnum), default=AISystemStatusEnum.DRAFT)

    # Assessment
    assessment_date = Column(DateTime)
    assessment_result = Column(JSON)                                      # Full assessment result
    obligations = Column(JSON)                                            # List of AI Act obligations
    risk_factors = Column(JSON)                                           # Risk factors from assessment
    recommendations = Column(JSON)                                        # Recommendations from assessment

    # Timestamps
    created_at = Column(DateTime, default=datetime.utcnow)
    updated_at = Column(DateTime, default=datetime.utcnow, onupdate=datetime.utcnow)

    __table_args__ = (
        Index('ix_ai_system_classification', 'classification'),
        Index('ix_ai_system_status', 'status'),
    )

    def __repr__(self):
        return f"<AISystem {self.name} ({self.classification.value})>"


class AuditExportDB(Base):
    """
    Tracks audit export packages generated for external auditors.
    """
    __tablename__ = 'compliance_audit_exports'

    id = Column(String(36), primary_key=True, default=lambda: str(uuid.uuid4()))

    export_type = Column(String(50), nullable=False)                     # "full", "controls_only", "evidence_only"
    export_name = Column(String(200))                                    # User-friendly name

    # Scope
    included_regulations = Column(JSON)                                  # List of regulation codes
    included_domains = Column(JSON)                                      # List of control domains
    date_range_start = Column(Date)
    date_range_end = Column(Date)

    # Generation
    requested_by = Column(String(100), nullable=False)
    requested_at = Column(DateTime, nullable=False, default=datetime.utcnow)
    completed_at = Column(DateTime)

    # Output
    file_path = Column(String(500))
    file_hash = Column(String(64))                                       # SHA-256 of ZIP
    file_size_bytes = Column(Integer)

    status = Column(Enum(ExportStatusEnum), default=ExportStatusEnum.PENDING)
    error_message = Column(Text)

    # Statistics
    total_controls = Column(Integer)
    total_evidence = Column(Integer)
    compliance_score = Column(Float)

    # Timestamps
    created_at = Column(DateTime, default=datetime.utcnow)
    updated_at = Column(DateTime, default=datetime.utcnow, onupdate=datetime.utcnow)

    def __repr__(self):
        return f"<AuditExport {self.export_type} by {self.requested_by}>"


# ============================================================================
# SERVICE MODULE REGISTRY (Sprint 3)
# ============================================================================

class ServiceModuleDB(Base):
    """
    Registry of all Breakpilot services/modules for compliance mapping.

    Tracks which regulations apply to which services, enabling:
    - Service-specific compliance views
    - Aggregated risk per service
    - Gap analysis by module
    """
    __tablename__ = 'compliance_service_modules'

    id = Column(String(36), primary_key=True, default=lambda: str(uuid.uuid4()))
    name = Column(String(100), unique=True, nullable=False, index=True)  # e.g., "consent-service"
    display_name = Column(String(200), nullable=False)                     # e.g., "Go Consent Service"
    description = Column(Text)

    # Technical details
    service_type = Column(Enum(ServiceTypeEnum), nullable=False)
    port = Column(Integer)                                                 # Primary port (if applicable)
    technology_stack = Column(JSON)                                        # e.g., ["Go", "Gin", "PostgreSQL"]
    repository_path = Column(String(500))                                  # e.g., "/consent-service"
    docker_image = Column(String(200))                                     # e.g., "breakpilot-pwa-consent-service"

    # Data categories handled
    data_categories = Column(JSON)                                         # e.g., ["personal_data", "consent_records"]
    processes_pii = Column(Boolean, default=False)                         # Handles personally identifiable info?
    processes_health_data = Column(Boolean, default=False)                 # Handles special category health data?
    ai_components = Column(Boolean, default=False)                         # Contains AI/ML components?

    # Status
    is_active = Column(Boolean, default=True)
    criticality = Column(String(20), default="medium")                     # "critical", "high", "medium", "low"

    # Compliance aggregation
    compliance_score = Column(Float)                                       # Calculated score 0-100
    last_compliance_check = Column(DateTime)

    # Owner
    owner_team = Column(String(100))                                       # e.g., "Backend Team"
    owner_contact = Column(String(200))                                    # e.g., "backend@breakpilot.app"

    # Timestamps
    created_at = Column(DateTime, default=datetime.utcnow)
    updated_at = Column(DateTime, default=datetime.utcnow, onupdate=datetime.utcnow)

    # Relationships
    regulation_mappings = relationship("ModuleRegulationMappingDB", back_populates="module", cascade="all, delete-orphan")
    module_risks = relationship("ModuleRiskDB", back_populates="module", cascade="all, delete-orphan")

    __table_args__ = (
        Index('ix_module_type_active', 'service_type', 'is_active'),
    )

    def __repr__(self):
        return f"<ServiceModule {self.name}: {self.display_name}>"


class ModuleRegulationMappingDB(Base):
    """
    Maps services to applicable regulations with relevance level.

    Enables filtering: "Show all GDPR requirements for consent-service"
    """
    __tablename__ = 'compliance_module_regulations'

    id = Column(String(36), primary_key=True, default=lambda: str(uuid.uuid4()))
    module_id = Column(String(36), ForeignKey('compliance_service_modules.id'), nullable=False, index=True)
    regulation_id = Column(String(36), ForeignKey('compliance_regulations.id'), nullable=False, index=True)

    relevance_level = Column(Enum(RelevanceLevelEnum), nullable=False, default=RelevanceLevelEnum.MEDIUM)
    notes = Column(Text)                                                   # Why this regulation applies
    applicable_articles = Column(JSON)                                     # List of specific articles that apply

    # Timestamps
    created_at = Column(DateTime, default=datetime.utcnow)
    updated_at = Column(DateTime, default=datetime.utcnow, onupdate=datetime.utcnow)

    # Relationships
    module = relationship("ServiceModuleDB", back_populates="regulation_mappings")
    regulation = relationship("RegulationDB")

    __table_args__ = (
        Index('ix_module_regulation', 'module_id', 'regulation_id', unique=True),
    )


class ModuleRiskDB(Base):
    """
    Service-specific risks aggregated from requirements and controls.
    """
    __tablename__ = 'compliance_module_risks'

    id = Column(String(36), primary_key=True, default=lambda: str(uuid.uuid4()))
    module_id = Column(String(36), ForeignKey('compliance_service_modules.id'), nullable=False, index=True)
    risk_id = Column(String(36), ForeignKey('compliance_risks.id'), nullable=False, index=True)

    # Module-specific assessment
    module_likelihood = Column(Integer)                                    # 1-5, may differ from global
    module_impact = Column(Integer)                                        # 1-5, may differ from global
    module_risk_level = Column(Enum(RiskLevelEnum))

    assessment_notes = Column(Text)                                        # Module-specific notes

    # Timestamps
    created_at = Column(DateTime, default=datetime.utcnow)
    updated_at = Column(DateTime, default=datetime.utcnow, onupdate=datetime.utcnow)

    # Relationships
    module = relationship("ServiceModuleDB", back_populates="module_risks")
    risk = relationship("RiskDB")

    __table_args__ = (
        Index('ix_module_risk', 'module_id', 'risk_id', unique=True),
    )


# ============================================================================
# AUDIT SESSION & SIGN-OFF (Sprint 3 - Phase 3)
# ============================================================================

class AuditResultEnum(str, enum.Enum):
    """Result of an audit sign-off for a requirement."""
    COMPLIANT = "compliant"                    # Fully compliant
    COMPLIANT_WITH_NOTES = "compliant_notes"   # Compliant with observations
    NON_COMPLIANT = "non_compliant"            # Not compliant - remediation required
    NOT_APPLICABLE = "not_applicable"          # Not applicable to this audit
    PENDING = "pending"                        # Not yet reviewed


class AuditSessionStatusEnum(str, enum.Enum):
    """Status of an audit session."""
    DRAFT = "draft"                            # Session created, not started
    IN_PROGRESS = "in_progress"                # Audit in progress
    COMPLETED = "completed"                    # All items reviewed
    ARCHIVED = "archived"                      # Historical record


class AuditSessionDB(Base):
    """
    Audit session for structured compliance reviews.

    Enables auditors to:
    - Create named audit sessions (e.g., "Q1 2026 GDPR Audit")
    - Track progress through requirements
    - Sign off individual items with digital signatures
    - Generate audit reports
    """
    __tablename__ = 'compliance_audit_sessions'

    id = Column(String(36), primary_key=True, default=lambda: str(uuid.uuid4()))
    name = Column(String(200), nullable=False)                              # e.g., "Q1 2026 Compliance Audit"
    description = Column(Text)

    # Auditor information
    auditor_name = Column(String(100), nullable=False)                      # e.g., "Dr. Thomas Müller"
    auditor_email = Column(String(200))
    auditor_organization = Column(String(200))                              # External auditor company

    # Session scope
    status = Column(Enum(AuditSessionStatusEnum), default=AuditSessionStatusEnum.DRAFT)
    regulation_ids = Column(JSON)                                           # Filter: ["GDPR", "AIACT"] or null for all

    # Progress tracking
    total_items = Column(Integer, default=0)
    completed_items = Column(Integer, default=0)
    compliant_count = Column(Integer, default=0)
    non_compliant_count = Column(Integer, default=0)

    # Timestamps
    created_at = Column(DateTime, default=datetime.utcnow)
    started_at = Column(DateTime)                                           # When audit began
    completed_at = Column(DateTime)                                         # When audit finished
    updated_at = Column(DateTime, default=datetime.utcnow, onupdate=datetime.utcnow)

    # Relationships
    signoffs = relationship("AuditSignOffDB", back_populates="session", cascade="all, delete-orphan")

    __table_args__ = (
        Index('ix_audit_session_status', 'status'),
        Index('ix_audit_session_auditor', 'auditor_name'),
    )

    def __repr__(self):
        return f"<AuditSession {self.name} ({self.status.value})>"

    @property
    def completion_percentage(self) -> float:
        """Calculate completion percentage."""
        if self.total_items == 0:
            return 0.0
        return round((self.completed_items / self.total_items) * 100, 1)


class AuditSignOffDB(Base):
    """
    Individual sign-off for a requirement within an audit session.

    Features:
    - Records audit result (compliant, non-compliant, etc.)
    - Stores auditor notes and observations
    - Creates digital signature (SHA-256 hash) for tamper evidence
    """
    __tablename__ = 'compliance_audit_signoffs'

    id = Column(String(36), primary_key=True, default=lambda: str(uuid.uuid4()))
    session_id = Column(String(36), ForeignKey('compliance_audit_sessions.id'), nullable=False, index=True)
    requirement_id = Column(String(36), ForeignKey('compliance_requirements.id'), nullable=False, index=True)

    # Audit result
    result = Column(Enum(AuditResultEnum), default=AuditResultEnum.PENDING)
    notes = Column(Text)                                                    # Auditor observations

    # Evidence references for this sign-off
    evidence_ids = Column(JSON)                                             # List of evidence IDs reviewed

    # Digital signature (SHA-256 hash of result + auditor + timestamp)
    signature_hash = Column(String(64))                                     # SHA-256 hex string
    signed_at = Column(DateTime)
    signed_by = Column(String(100))                                         # Auditor name at time of signing

    # Timestamps
    created_at = Column(DateTime, default=datetime.utcnow)
    updated_at = Column(DateTime, default=datetime.utcnow, onupdate=datetime.utcnow)

    # Relationships
    session = relationship("AuditSessionDB", back_populates="signoffs")
    requirement = relationship("RequirementDB")

    __table_args__ = (
        Index('ix_signoff_session_requirement', 'session_id', 'requirement_id', unique=True),
        Index('ix_signoff_result', 'result'),
    )

    def __repr__(self):
        return f"<AuditSignOff {self.requirement_id}: {self.result.value}>"

    def create_signature(self, auditor_name: str) -> str:
        """
        Create a digital signature for this sign-off.

        Returns SHA-256 hash of: result + requirement_id + auditor_name + timestamp
        """
        import hashlib
        from datetime import datetime

        timestamp = datetime.utcnow().isoformat()
        data = f"{self.result.value}|{self.requirement_id}|{auditor_name}|{timestamp}"
        signature = hashlib.sha256(data.encode()).hexdigest()

        self.signature_hash = signature
        self.signed_at = datetime.utcnow()
        self.signed_by = auditor_name

        return signature


# ============================================================================
# ISO 27001 ISMS MODELS (Kapitel 4-10)
# ============================================================================

class ApprovalStatusEnum(str, enum.Enum):
    """Approval status for ISMS documents."""
    DRAFT = "draft"
    UNDER_REVIEW = "under_review"
    APPROVED = "approved"
    SUPERSEDED = "superseded"


class FindingTypeEnum(str, enum.Enum):
    """ISO 27001 audit finding classification."""
    MAJOR = "major"              # Major nonconformity - blocks certification
    MINOR = "minor"              # Minor nonconformity - requires CAPA
    OFI = "ofi"                  # Opportunity for Improvement
    POSITIVE = "positive"        # Positive observation


class FindingStatusEnum(str, enum.Enum):
    """Status of an audit finding."""
    OPEN = "open"
    IN_PROGRESS = "in_progress"
    CORRECTIVE_ACTION_PENDING = "capa_pending"
    VERIFICATION_PENDING = "verification_pending"
    VERIFIED = "verified"
    CLOSED = "closed"


class CAPATypeEnum(str, enum.Enum):
    """Type of corrective/preventive action."""
    CORRECTIVE = "corrective"    # Fix the nonconformity
    PREVENTIVE = "preventive"    # Prevent recurrence
    BOTH = "both"


class ISMSScopeDB(Base):
    """
    ISMS Scope Definition (ISO 27001 Kapitel 4.3)

    Defines the boundaries and applicability of the ISMS.
    This is MANDATORY for certification.
    """
    __tablename__ = 'compliance_isms_scope'

    id = Column(String(36), primary_key=True, default=lambda: str(uuid.uuid4()))
    version = Column(String(20), nullable=False, default="1.0")

    # Scope definition
    scope_statement = Column(Text, nullable=False)              # Main scope text
    included_locations = Column(JSON)                           # List of locations
    included_processes = Column(JSON)                           # List of processes
    included_services = Column(JSON)                            # List of services/products
    excluded_items = Column(JSON)                               # Explicitly excluded items
    exclusion_justification = Column(Text)                      # Why items are excluded

    # Boundaries
    organizational_boundary = Column(Text)                      # Legal entity, departments
    physical_boundary = Column(Text)                            # Locations, networks
    technical_boundary = Column(Text)                           # Systems, applications

    # Approval
    status = Column(Enum(ApprovalStatusEnum), default=ApprovalStatusEnum.DRAFT)
    approved_by = Column(String(100))
    approved_at = Column(DateTime)
    approval_signature = Column(String(64))                     # SHA-256 hash

    # Validity
    effective_date = Column(Date)
    review_date = Column(Date)                                  # Next mandatory review

    # Timestamps
    created_at = Column(DateTime, default=datetime.utcnow)
    updated_at = Column(DateTime, default=datetime.utcnow, onupdate=datetime.utcnow)
    created_by = Column(String(100))
    updated_by = Column(String(100))

    __table_args__ = (
        Index('ix_isms_scope_status', 'status'),
    )

    def __repr__(self):
        return f"<ISMSScope v{self.version} ({self.status.value})>"


class ISMSContextDB(Base):
    """
    ISMS Context (ISO 27001 Kapitel 4.1, 4.2)

    Documents internal/external issues and interested parties.
    """
    __tablename__ = 'compliance_isms_context'

    id = Column(String(36), primary_key=True, default=lambda: str(uuid.uuid4()))
    version = Column(String(20), nullable=False, default="1.0")

    # 4.1 Internal issues
    internal_issues = Column(JSON)                              # List of {"issue": "", "impact": "", "treatment": ""}

    # 4.1 External issues
    external_issues = Column(JSON)                              # List of {"issue": "", "impact": "", "treatment": ""}

    # 4.2 Interested parties
    interested_parties = Column(JSON)                           # List of {"party": "", "requirements": [], "relevance": ""}

    # Legal/regulatory requirements
    regulatory_requirements = Column(JSON)                      # DSGVO, AI Act, etc.
    contractual_requirements = Column(JSON)                     # Customer contracts

    # Analysis
    swot_strengths = Column(JSON)
    swot_weaknesses = Column(JSON)
    swot_opportunities = Column(JSON)
    swot_threats = Column(JSON)

    # Approval
    status = Column(Enum(ApprovalStatusEnum), default=ApprovalStatusEnum.DRAFT)
    approved_by = Column(String(100))
    approved_at = Column(DateTime)

    # Review
    last_reviewed_at = Column(DateTime)
    next_review_date = Column(Date)

    # Timestamps
    created_at = Column(DateTime, default=datetime.utcnow)
    updated_at = Column(DateTime, default=datetime.utcnow, onupdate=datetime.utcnow)

    def __repr__(self):
        return f"<ISMSContext v{self.version}>"


class ISMSPolicyDB(Base):
    """
    ISMS Policies (ISO 27001 Kapitel 5.2)

    Information security policy and sub-policies.
    """
    __tablename__ = 'compliance_isms_policies'

    id = Column(String(36), primary_key=True, default=lambda: str(uuid.uuid4()))
    policy_id = Column(String(30), unique=True, nullable=False, index=True)  # e.g., "POL-ISMS-001"

    # Policy details
    title = Column(String(200), nullable=False)
    policy_type = Column(String(50), nullable=False)            # "master", "operational", "technical"
    description = Column(Text)
    policy_text = Column(Text, nullable=False)                  # Full policy content

    # Scope
    applies_to = Column(JSON)                                   # Roles, departments, systems

    # Document control
    version = Column(String(20), nullable=False, default="1.0")
    status = Column(Enum(ApprovalStatusEnum), default=ApprovalStatusEnum.DRAFT)

    # Approval chain
    authored_by = Column(String(100))
    reviewed_by = Column(String(100))
    approved_by = Column(String(100))                           # Must be top management
    approved_at = Column(DateTime)
    approval_signature = Column(String(64))

    # Validity
    effective_date = Column(Date)
    review_frequency_months = Column(Integer, default=12)
    next_review_date = Column(Date)

    # References
    parent_policy_id = Column(String(36), ForeignKey('compliance_isms_policies.id'))
    related_controls = Column(JSON)                             # List of control_ids

    # Document path
    document_path = Column(String(500))                         # Link to full document

    # Timestamps
    created_at = Column(DateTime, default=datetime.utcnow)
    updated_at = Column(DateTime, default=datetime.utcnow, onupdate=datetime.utcnow)

    __table_args__ = (
        Index('ix_policy_type_status', 'policy_type', 'status'),
    )

    def __repr__(self):
        return f"<ISMSPolicy {self.policy_id}: {self.title}>"


class SecurityObjectiveDB(Base):
    """
    Security Objectives (ISO 27001 Kapitel 6.2)

    Measurable information security objectives.
    """
    __tablename__ = 'compliance_security_objectives'

    id = Column(String(36), primary_key=True, default=lambda: str(uuid.uuid4()))
    objective_id = Column(String(30), unique=True, nullable=False, index=True)  # e.g., "OBJ-001"

    # Objective definition
    title = Column(String(200), nullable=False)
    description = Column(Text)
    category = Column(String(50))                               # "availability", "confidentiality", "integrity", "compliance"

    # SMART criteria
    specific = Column(Text)                                     # What exactly
    measurable = Column(Text)                                   # How measured
    achievable = Column(Text)                                   # Is it realistic
    relevant = Column(Text)                                     # Why important
    time_bound = Column(Text)                                   # Deadline

    # Metrics
    kpi_name = Column(String(100))
    kpi_target = Column(String(100))                            # Target value
    kpi_current = Column(String(100))                           # Current value
    kpi_unit = Column(String(50))                               # %, count, score
    measurement_frequency = Column(String(50))                  # monthly, quarterly

    # Responsibility
    owner = Column(String(100))
    accountable = Column(String(100))                           # RACI: Accountable

    # Status
    status = Column(String(30), default="active")               # active, achieved, not_achieved, cancelled
    progress_percentage = Column(Integer, default=0)

    # Timeline
    target_date = Column(Date)
    achieved_date = Column(Date)

    # Linked items
    related_controls = Column(JSON)
    related_risks = Column(JSON)

    # Approval
    approved_by = Column(String(100))
    approved_at = Column(DateTime)

    # Timestamps
    created_at = Column(DateTime, default=datetime.utcnow)
    updated_at = Column(DateTime, default=datetime.utcnow, onupdate=datetime.utcnow)

    __table_args__ = (
        Index('ix_objective_status', 'status'),
        Index('ix_objective_category', 'category'),
    )

    def __repr__(self):
        return f"<SecurityObjective {self.objective_id}: {self.title}>"


class StatementOfApplicabilityDB(Base):
    """
    Statement of Applicability (SoA) - ISO 27001 Anhang A Mapping

    Documents which Annex A controls are applicable and why.
    This is MANDATORY for certification.
    """
    __tablename__ = 'compliance_soa'

    id = Column(String(36), primary_key=True, default=lambda: str(uuid.uuid4()))

    # ISO 27001:2022 Annex A reference
    annex_a_control = Column(String(20), nullable=False, index=True)  # e.g., "A.5.1"
    annex_a_title = Column(String(300), nullable=False)
    annex_a_category = Column(String(100))                      # "Organizational", "People", "Physical", "Technological"

    # Applicability decision
    is_applicable = Column(Boolean, nullable=False)
    applicability_justification = Column(Text, nullable=False)  # MUST be documented

    # Implementation status
    implementation_status = Column(String(30), default="planned")  # planned, partial, implemented, not_implemented
    implementation_notes = Column(Text)

    # Mapping to our controls
    breakpilot_control_ids = Column(JSON)                       # List of our control_ids that address this
    coverage_level = Column(String(20), default="full")         # full, partial, planned

    # Evidence
    evidence_description = Column(Text)
    evidence_ids = Column(JSON)                                 # Links to EvidenceDB

    # Risk-based justification (for exclusions)
    risk_assessment_notes = Column(Text)                        # If not applicable, explain why
    compensating_controls = Column(Text)                        # If partial, explain compensating measures

    # Approval
    reviewed_by = Column(String(100))
    reviewed_at = Column(DateTime)
    approved_by = Column(String(100))
    approved_at = Column(DateTime)

    # Version tracking
    version = Column(String(20), default="1.0")

    # Timestamps
    created_at = Column(DateTime, default=datetime.utcnow)
    updated_at = Column(DateTime, default=datetime.utcnow, onupdate=datetime.utcnow)

    __table_args__ = (
        Index('ix_soa_annex_control', 'annex_a_control', unique=True),
        Index('ix_soa_applicable', 'is_applicable'),
        Index('ix_soa_status', 'implementation_status'),
    )

    def __repr__(self):
        return f"<SoA {self.annex_a_control}: {'Applicable' if self.is_applicable else 'N/A'}>"


class AuditFindingDB(Base):
    """
    Audit Finding with ISO 27001 Classification (Major/Minor/OFI)

    Tracks findings from internal and external audits with proper
    classification and CAPA workflow.
    """
    __tablename__ = 'compliance_audit_findings'

    id = Column(String(36), primary_key=True, default=lambda: str(uuid.uuid4()))
    finding_id = Column(String(30), unique=True, nullable=False, index=True)  # e.g., "FIND-2026-001"

    # Source
    audit_session_id = Column(String(36), ForeignKey('compliance_audit_sessions.id'), index=True)
    internal_audit_id = Column(String(36), ForeignKey('compliance_internal_audits.id'), index=True)

    # Classification (CRITICAL for ISO 27001!)
    finding_type = Column(Enum(FindingTypeEnum), nullable=False)

    # ISO reference
    iso_chapter = Column(String(20))                            # e.g., "6.1.2", "9.2"
    annex_a_control = Column(String(20))                        # e.g., "A.8.2"

    # Finding details
    title = Column(String(300), nullable=False)
    description = Column(Text, nullable=False)
    objective_evidence = Column(Text, nullable=False)           # What the auditor observed

    # Root cause analysis
    root_cause = Column(Text)
    root_cause_method = Column(String(50))                      # "5-why", "fishbone", "pareto"

    # Impact assessment
    impact_description = Column(Text)
    affected_processes = Column(JSON)
    affected_assets = Column(JSON)

    # Status tracking
    status = Column(Enum(FindingStatusEnum), default=FindingStatusEnum.OPEN)

    # Responsibility
    owner = Column(String(100))                                 # Person responsible for closure
    auditor = Column(String(100))                               # Auditor who raised finding

    # Dates
    identified_date = Column(Date, nullable=False, default=date.today)
    due_date = Column(Date)                                     # Deadline for closure
    closed_date = Column(Date)

    # Verification
    verification_method = Column(Text)
    verified_by = Column(String(100))
    verified_at = Column(DateTime)
    verification_evidence = Column(Text)

    # Closure
    closure_notes = Column(Text)
    closed_by = Column(String(100))

    # Timestamps
    created_at = Column(DateTime, default=datetime.utcnow)
    updated_at = Column(DateTime, default=datetime.utcnow, onupdate=datetime.utcnow)

    # Relationships
    corrective_actions = relationship("CorrectiveActionDB", back_populates="finding", cascade="all, delete-orphan")

    __table_args__ = (
        Index('ix_finding_type_status', 'finding_type', 'status'),
        Index('ix_finding_due_date', 'due_date'),
    )

    def __repr__(self):
        return f"<AuditFinding {self.finding_id}: {self.finding_type.value}>"

    @property
    def is_blocking(self) -> bool:
        """Major findings block certification."""
        return self.finding_type == FindingTypeEnum.MAJOR and self.status != FindingStatusEnum.CLOSED


class CorrectiveActionDB(Base):
    """
    Corrective & Preventive Actions (CAPA) - ISO 27001 10.1

    Tracks actions taken to address nonconformities.
    """
    __tablename__ = 'compliance_corrective_actions'

    id = Column(String(36), primary_key=True, default=lambda: str(uuid.uuid4()))
    capa_id = Column(String(30), unique=True, nullable=False, index=True)  # e.g., "CAPA-2026-001"

    # Link to finding
    finding_id = Column(String(36), ForeignKey('compliance_audit_findings.id'), nullable=False, index=True)

    # Type
    capa_type = Column(Enum(CAPATypeEnum), nullable=False)

    # Action details
    title = Column(String(300), nullable=False)
    description = Column(Text, nullable=False)
    expected_outcome = Column(Text)

    # Responsibility
    assigned_to = Column(String(100), nullable=False)
    approved_by = Column(String(100))

    # Timeline
    planned_start = Column(Date)
    planned_completion = Column(Date, nullable=False)
    actual_completion = Column(Date)

    # Status
    status = Column(String(30), default="planned")              # planned, in_progress, completed, verified, cancelled
    progress_percentage = Column(Integer, default=0)

    # Resources
    estimated_effort_hours = Column(Integer)
    actual_effort_hours = Column(Integer)
    resources_required = Column(Text)

    # Evidence of implementation
    implementation_evidence = Column(Text)
    evidence_ids = Column(JSON)

    # Effectiveness review
    effectiveness_criteria = Column(Text)
    effectiveness_verified = Column(Boolean, default=False)
    effectiveness_verification_date = Column(Date)
    effectiveness_notes = Column(Text)

    # Timestamps
    created_at = Column(DateTime, default=datetime.utcnow)
    updated_at = Column(DateTime, default=datetime.utcnow, onupdate=datetime.utcnow)

    # Relationships
    finding = relationship("AuditFindingDB", back_populates="corrective_actions")

    __table_args__ = (
        Index('ix_capa_status', 'status'),
        Index('ix_capa_due', 'planned_completion'),
    )

    def __repr__(self):
        return f"<CAPA {self.capa_id}: {self.capa_type.value}>"


class ManagementReviewDB(Base):
    """
    Management Review (ISO 27001 Kapitel 9.3)

    Records mandatory management reviews of the ISMS.
    """
    __tablename__ = 'compliance_management_reviews'

    id = Column(String(36), primary_key=True, default=lambda: str(uuid.uuid4()))
    review_id = Column(String(30), unique=True, nullable=False, index=True)  # e.g., "MR-2026-Q1"

    # Review details
    title = Column(String(200), nullable=False)
    review_date = Column(Date, nullable=False)
    review_period_start = Column(Date)                          # Period being reviewed
    review_period_end = Column(Date)

    # Participants
    chairperson = Column(String(100), nullable=False)           # Usually top management
    attendees = Column(JSON)                                    # List of {"name": "", "role": ""}

    # 9.3 Review Inputs (mandatory!)
    input_previous_actions = Column(Text)                       # Status of previous review actions
    input_isms_changes = Column(Text)                           # Changes in internal/external issues
    input_security_performance = Column(Text)                   # Nonconformities, monitoring, audit results
    input_interested_party_feedback = Column(Text)
    input_risk_assessment_results = Column(Text)
    input_improvement_opportunities = Column(Text)

    # Additional inputs
    input_policy_effectiveness = Column(Text)
    input_objective_achievement = Column(Text)
    input_resource_adequacy = Column(Text)

    # 9.3 Review Outputs (mandatory!)
    output_improvement_decisions = Column(Text)                 # Decisions for improvement
    output_isms_changes = Column(Text)                          # Changes needed to ISMS
    output_resource_needs = Column(Text)                        # Resource requirements

    # Action items
    action_items = Column(JSON)                                 # List of {"action": "", "owner": "", "due_date": ""}

    # Overall assessment
    isms_effectiveness_rating = Column(String(20))              # "effective", "partially_effective", "not_effective"
    key_decisions = Column(Text)

    # Approval
    status = Column(String(30), default="draft")                # draft, conducted, approved
    approved_by = Column(String(100))
    approved_at = Column(DateTime)
    minutes_document_path = Column(String(500))                 # Link to meeting minutes

    # Next review
    next_review_date = Column(Date)

    # Timestamps
    created_at = Column(DateTime, default=datetime.utcnow)
    updated_at = Column(DateTime, default=datetime.utcnow, onupdate=datetime.utcnow)

    __table_args__ = (
        Index('ix_mgmt_review_date', 'review_date'),
        Index('ix_mgmt_review_status', 'status'),
    )

    def __repr__(self):
        return f"<ManagementReview {self.review_id}: {self.review_date}>"


class InternalAuditDB(Base):
    """
    Internal Audit (ISO 27001 Kapitel 9.2)

    Tracks internal audit program and individual audits.
    """
    __tablename__ = 'compliance_internal_audits'

    id = Column(String(36), primary_key=True, default=lambda: str(uuid.uuid4()))
    audit_id = Column(String(30), unique=True, nullable=False, index=True)  # e.g., "IA-2026-001"

    # Audit details
    title = Column(String(200), nullable=False)
    audit_type = Column(String(50), nullable=False)             # "scheduled", "surveillance", "special"

    # Scope
    scope_description = Column(Text, nullable=False)
    iso_chapters_covered = Column(JSON)                         # e.g., ["4", "5", "6.1"]
    annex_a_controls_covered = Column(JSON)                     # e.g., ["A.5", "A.6"]
    processes_covered = Column(JSON)
    departments_covered = Column(JSON)

    # Audit criteria
    criteria = Column(Text)                                     # Standards, policies being audited against

    # Timeline
    planned_date = Column(Date, nullable=False)
    actual_start_date = Column(Date)
    actual_end_date = Column(Date)

    # Audit team
    lead_auditor = Column(String(100), nullable=False)
    audit_team = Column(JSON)                                   # List of auditor names
    auditee_representatives = Column(JSON)                      # Who was interviewed

    # Status
    status = Column(String(30), default="planned")              # planned, in_progress, completed, cancelled

    # Results summary
    total_findings = Column(Integer, default=0)
    major_findings = Column(Integer, default=0)
    minor_findings = Column(Integer, default=0)
    ofi_count = Column(Integer, default=0)
    positive_observations = Column(Integer, default=0)

    # Conclusion
    audit_conclusion = Column(Text)
    overall_assessment = Column(String(30))                     # "conforming", "minor_nc", "major_nc"

    # Report
    report_date = Column(Date)
    report_document_path = Column(String(500))

    # Sign-off
    report_approved_by = Column(String(100))
    report_approved_at = Column(DateTime)

    # Follow-up
    follow_up_audit_required = Column(Boolean, default=False)
    follow_up_audit_id = Column(String(36))

    # Timestamps
    created_at = Column(DateTime, default=datetime.utcnow)
    updated_at = Column(DateTime, default=datetime.utcnow, onupdate=datetime.utcnow)

    # Relationships
    findings = relationship("AuditFindingDB", backref="internal_audit", foreign_keys=[AuditFindingDB.internal_audit_id])

    __table_args__ = (
        Index('ix_internal_audit_date', 'planned_date'),
        Index('ix_internal_audit_status', 'status'),
    )

    def __repr__(self):
        return f"<InternalAudit {self.audit_id}: {self.title}>"


class AuditTrailDB(Base):
    """
    Comprehensive Audit Trail for ISMS Changes

    Tracks all changes to compliance-relevant data for
    accountability and forensic analysis.
    """
    __tablename__ = 'compliance_audit_trail'

    id = Column(String(36), primary_key=True, default=lambda: str(uuid.uuid4()))

    # What changed
    entity_type = Column(String(50), nullable=False, index=True)  # "control", "risk", "policy", etc.
    entity_id = Column(String(36), nullable=False, index=True)
    entity_name = Column(String(200))                           # Human-readable identifier

    # Action
    action = Column(String(20), nullable=False)                 # "create", "update", "delete", "approve", "sign"

    # Change details
    field_changed = Column(String(100))                         # Which field (for updates)
    old_value = Column(Text)
    new_value = Column(Text)
    change_summary = Column(Text)                               # Human-readable summary

    # Who & When
    performed_by = Column(String(100), nullable=False)
    performed_at = Column(DateTime, nullable=False, default=datetime.utcnow)

    # Context
    ip_address = Column(String(45))
    user_agent = Column(String(500))
    session_id = Column(String(100))

    # Integrity
    checksum = Column(String(64))                               # SHA-256 of the change

    # Timestamps (immutable after creation)
    created_at = Column(DateTime, nullable=False, default=datetime.utcnow)

    __table_args__ = (
        Index('ix_audit_trail_entity', 'entity_type', 'entity_id'),
        Index('ix_audit_trail_time', 'performed_at'),
        Index('ix_audit_trail_user', 'performed_by'),
    )

    def __repr__(self):
        return f"<AuditTrail {self.action} on {self.entity_type}/{self.entity_id}>"


class ISMSReadinessCheckDB(Base):
    """
    ISMS Readiness Check Results

    Stores automated pre-audit checks to identify potential
    Major findings before external audit.
    """
    __tablename__ = 'compliance_isms_readiness'

    id = Column(String(36), primary_key=True, default=lambda: str(uuid.uuid4()))

    # Check run
    check_date = Column(DateTime, nullable=False, default=datetime.utcnow)
    triggered_by = Column(String(100))                          # "scheduled", "manual", "pre-audit"

    # Overall status
    overall_status = Column(String(20), nullable=False)         # "ready", "at_risk", "not_ready"
    certification_possible = Column(Boolean, nullable=False)

    # Chapter-by-chapter status (ISO 27001)
    chapter_4_status = Column(String(20))                       # Context
    chapter_5_status = Column(String(20))                       # Leadership
    chapter_6_status = Column(String(20))                       # Planning
    chapter_7_status = Column(String(20))                       # Support
    chapter_8_status = Column(String(20))                       # Operation
    chapter_9_status = Column(String(20))                       # Performance
    chapter_10_status = Column(String(20))                      # Improvement

    # Potential Major findings
    potential_majors = Column(JSON)                             # List of {"check": "", "status": "", "recommendation": ""}

    # Potential Minor findings
    potential_minors = Column(JSON)

    # Improvement opportunities
    improvement_opportunities = Column(JSON)

    # Scores
    readiness_score = Column(Float)                             # 0-100
    documentation_score = Column(Float)
    implementation_score = Column(Float)
    evidence_score = Column(Float)

    # Recommendations
    priority_actions = Column(JSON)                             # List of recommended actions before audit

    # Timestamps
    created_at = Column(DateTime, default=datetime.utcnow)

    __table_args__ = (
        Index('ix_readiness_date', 'check_date'),
        Index('ix_readiness_status', 'overall_status'),
    )

    def __repr__(self):
        return f"<ISMSReadiness {self.check_date}: {self.overall_status}>"