-- Migration 076: Anti-Fake-Evidence Guardrails (Phase 1)
--
-- Prevents "Compliance-Theater": generated content passed off as real evidence,
-- controls without evidence marked as "pass", unvalidated 100% compliance claims.
--
-- Changes:
--   1. New ENUM types for evidence confidence + truth status
--   2. New columns on compliance_evidence (confidence, truth, review tracking)
--   3. New value 'in_progress' for controlstatusenum
--   4. status_justification column on compliance_controls
--   5. New table compliance_llm_generation_audit
--   6. Backfill existing evidence based on source
--   7. Indexes on new columns

-- ============================================================================
-- 1. New ENUM types
-- ============================================================================

-- NOTE: CREATE TYPE cannot run inside a transaction block when combined with
-- ALTER TYPE ... ADD VALUE.  Each statement here is auto-committed separately
-- when executed outside a transaction (which is the default for psql scripts).

CREATE TYPE evidence_confidence_level AS ENUM (
    'E0',   -- Generated / no real evidence (LLM output, placeholder)
    'E1',   -- Uploaded but unreviewed (manual upload, no hash, no reviewer)
    'E2',   -- Reviewed internally (human reviewed, hash verified)
    'E3',   -- Observed by system (CI/CD pipeline, API with hash)
    'E4'    -- Validated by external auditor
);

CREATE TYPE evidence_truth_status AS ENUM (
    'generated',              -- Created by LLM / system generation
    'uploaded',               -- Manually uploaded by user
    'observed',               -- Automatically observed (CI/CD, monitoring)
    'validated_internal',     -- Reviewed + approved by internal reviewer
    'rejected',               -- Reviewed and rejected
    'provided_to_auditor',    -- Shared with external auditor
    'accepted_by_auditor'     -- Accepted by external auditor
);

-- ============================================================================
-- 2. Add 'in_progress' to controlstatusenum
-- ============================================================================
-- ALTER TYPE ... ADD VALUE cannot run inside a transaction.

ALTER TYPE controlstatusenum ADD VALUE IF NOT EXISTS 'in_progress';

-- ============================================================================
-- 3. New columns on compliance_evidence
-- ============================================================================

ALTER TABLE compliance_evidence
    ADD COLUMN IF NOT EXISTS confidence_level evidence_confidence_level DEFAULT 'E1',
    ADD COLUMN IF NOT EXISTS truth_status evidence_truth_status DEFAULT 'uploaded',
    ADD COLUMN IF NOT EXISTS generation_mode VARCHAR(100),
    ADD COLUMN IF NOT EXISTS may_be_used_as_evidence BOOLEAN DEFAULT TRUE,
    ADD COLUMN IF NOT EXISTS reviewed_by VARCHAR(200),
    ADD COLUMN IF NOT EXISTS reviewed_at TIMESTAMPTZ;

-- ============================================================================
-- 4. status_justification on compliance_controls
-- ============================================================================

ALTER TABLE compliance_controls
    ADD COLUMN IF NOT EXISTS status_justification TEXT;

-- ============================================================================
-- 5. LLM Generation Audit table
-- ============================================================================

CREATE TABLE IF NOT EXISTS compliance_llm_generation_audit (
    id              VARCHAR(36) PRIMARY KEY DEFAULT gen_random_uuid()::text,
    tenant_id       VARCHAR(36),
    entity_type     VARCHAR(50) NOT NULL,      -- 'evidence', 'control', 'document', ...
    entity_id       VARCHAR(36),               -- FK to the generated entity
    generation_mode VARCHAR(100) NOT NULL,      -- 'draft_assistance', 'auto_generation', ...
    truth_status    evidence_truth_status NOT NULL DEFAULT 'generated',
    may_be_used_as_evidence BOOLEAN NOT NULL DEFAULT FALSE,
    llm_model       VARCHAR(100),
    llm_provider    VARCHAR(50),               -- 'ollama', 'anthropic', ...
    prompt_hash     VARCHAR(64),               -- SHA-256 of the prompt
    input_summary   TEXT,                      -- Truncated input for auditability
    output_summary  TEXT,                      -- Truncated output for auditability
    metadata        JSONB DEFAULT '{}'::jsonb,
    created_at      TIMESTAMPTZ DEFAULT NOW(),
    updated_at      TIMESTAMPTZ DEFAULT NOW()
);

-- ============================================================================
-- 6. Backfill existing evidence based on source
-- ============================================================================

-- CI pipeline evidence → E3 + observed
UPDATE compliance_evidence
SET confidence_level = 'E3',
    truth_status = 'observed'
WHERE source = 'ci_pipeline'
  AND confidence_level = 'E1';

-- API evidence → E3 + observed
UPDATE compliance_evidence
SET confidence_level = 'E3',
    truth_status = 'observed'
WHERE source = 'api'
  AND confidence_level = 'E1';

-- Manual/upload evidence stays at E1 + uploaded (default)

-- Generated evidence → E0 + generated
UPDATE compliance_evidence
SET confidence_level = 'E0',
    truth_status = 'generated',
    may_be_used_as_evidence = FALSE
WHERE source = 'generated'
  AND confidence_level = 'E1';

-- ============================================================================
-- 7. Indexes
-- ============================================================================

CREATE INDEX IF NOT EXISTS ix_evidence_confidence ON compliance_evidence (confidence_level);
CREATE INDEX IF NOT EXISTS ix_evidence_truth_status ON compliance_evidence (truth_status);
CREATE INDEX IF NOT EXISTS ix_evidence_may_be_used ON compliance_evidence (may_be_used_as_evidence);
CREATE INDEX IF NOT EXISTS ix_llm_audit_entity ON compliance_llm_generation_audit (entity_type, entity_id);
CREATE INDEX IF NOT EXISTS ix_llm_audit_tenant ON compliance_llm_generation_audit (tenant_id);