"""Persist CRA risk-assessment snapshots — the CRA Art. 13 'running system'.

Reuses the existing compliance_cra_documents table (NO new schema, frozen DB):
a snapshot is a document of doc_type='doc_risk_assessment', versioned, with the
full assessment stored in generation_context. Each new snapshot supersedes the
prior one, giving an auditable history over the product lifecycle.
"""
import json

from sqlalchemy import text

from database import SessionLocal

DOC_TYPE = "doc_risk_assessment"


def assessment_markdown(assessment: dict) -> str:
    by = assessment.get("by_risk", {})
    lines = [
        "# CRA-Cyber-Risikobeurteilung",
        "",
        "- Befunde gesamt: {}".format(assessment.get("findings_total", 0)),
        "- Abdeckung: {} %".format(assessment.get("coverage_pct", 0)),
        "- Risiko: kritisch {} · hoch {} · mittel {} · niedrig {}".format(
            by.get("CRITICAL", 0), by.get("HIGH", 0), by.get("MEDIUM", 0), by.get("LOW", 0)),
        "- CRA-Anforderungen betroffen: {} / 40".format(len(assessment.get("requirements_touched", []))),
        "",
        "## Priorisierte Befunde",
    ]
    for m in assessment.get("mapped", []):
        lines.append("- [{}] {} → {} — {}".format(
            m.get("priority_tier", ""), m.get("finding_id", ""),
            m.get("primary_requirement", ""), m.get("priority_reason", "")))
    if assessment.get("cross_links"):
        lines += ["", "## Cyber trifft Safety"]
        for cl in assessment["cross_links"]:
            lines.append("- {} ← {}".format(cl.get("safety_ref", ""), ", ".join(cl.get("cyber_finding_ids", []))))
    return "\n".join(lines)


def save_snapshot(cra_project_id: str, tenant_id: str, assessment: dict,
                  title: str = "CRA-Cyber-Risikobeurteilung") -> dict:
    db = SessionLocal()
    try:
        db.execute(text("""
            UPDATE compliance_cra_documents SET status='superseded', superseded_at=NOW()
            WHERE cra_project_id = CAST(:pid AS uuid) AND tenant_id = :tid
              AND doc_type = :dt AND status != 'superseded'
        """), {"pid": cra_project_id, "tid": tenant_id, "dt": DOC_TYPE})
        ver = db.execute(text("""
            SELECT COALESCE(MAX(version), 0) + 1 FROM compliance_cra_documents
            WHERE cra_project_id = CAST(:pid AS uuid) AND tenant_id = :tid AND doc_type = :dt
        """), {"pid": cra_project_id, "tid": tenant_id, "dt": DOC_TYPE}).scalar()
        coverage = {"covered": assessment.get("requirements_touched", []), "total": 40}
        row = db.execute(text("""
            INSERT INTO compliance_cra_documents
                (cra_project_id, tenant_id, doc_type, title, content_md, version,
                 requirements_coverage, generation_context, status)
            VALUES (CAST(:pid AS uuid), :tid, :dt, :title, :md, :ver,
                    CAST(:cov AS jsonb), CAST(:ctx AS jsonb), 'draft')
            RETURNING id, version, generated_at
        """), {"pid": cra_project_id, "tid": tenant_id, "dt": DOC_TYPE, "title": title,
               "md": assessment_markdown(assessment), "ver": ver,
               "cov": json.dumps(coverage), "ctx": json.dumps(assessment)}).fetchone()
        db.commit()
        return {"id": str(row.id), "version": row.version, "generated_at": row.generated_at.isoformat()}
    except Exception:
        db.rollback()
        raise
    finally:
        db.close()


def list_snapshots(cra_project_id: str, tenant_id: str) -> list:
    db = SessionLocal()
    try:
        rows = db.execute(text("""
            SELECT id, version, status, generated_at, requirements_coverage
            FROM compliance_cra_documents
            WHERE cra_project_id = CAST(:pid AS uuid) AND tenant_id = :tid AND doc_type = :dt
            ORDER BY version DESC
        """), {"pid": cra_project_id, "tid": tenant_id, "dt": DOC_TYPE}).fetchall()
        return [{"id": str(r.id), "version": r.version, "status": r.status,
                 "generated_at": r.generated_at.isoformat(),
                 "coverage": r.requirements_coverage} for r in rows]
    finally:
        db.close()


def get_snapshot(snapshot_id: str, tenant_id: str):
    db = SessionLocal()
    try:
        r = db.execute(text("""
            SELECT id, version, status, generated_at, content_md, generation_context
            FROM compliance_cra_documents
            WHERE id = CAST(:sid AS uuid) AND tenant_id = :tid AND doc_type = :dt
        """), {"sid": snapshot_id, "tid": tenant_id, "dt": DOC_TYPE}).fetchone()
        if not r:
            return None
        return {"id": str(r.id), "version": r.version, "status": r.status,
                "generated_at": r.generated_at.isoformat(), "content_md": r.content_md,
                "assessment": r.generation_context}
    finally:
        db.close()