"""Plan snapshot capture & persistence (AP1.14)."""

from __future__ import annotations

import json
from typing import Any, Optional

from psycopg2.extras import RealDictCursor, Json

from db import get_connection
from services.audit import log_audit
from services.initiatives import get_initiative
from services import roadmap as roadmap_service
from services import roadmap_criteria as criteria_service


def _serialize_snapshot(row: dict[str, Any]) -> dict[str, Any]:
    result = dict(row)
    for key in ("id", "tenant_id", "initiative_id", "roadmap_id", "created_by_user_id"):
        if result.get(key):
            result[key] = str(result[key])
    if result.get("created_at"):
        result["created_at"] = result["created_at"].isoformat()
    payload = result.get("plan_payload")
    if isinstance(payload, str):
        result["plan_payload"] = json.loads(payload)
    return result


def capture_plan_payload(
    *, tenant_id: str, initiative_id: str
) -> dict[str, Any]:
    """Soll-Struktur: Topologie + Kriterien-Definitionen ohne Ist-Status."""
    items = roadmap_service.list_roadmap_items_for_initiative(
        tenant_id=tenant_id, initiative_id=initiative_id
    )
    dependencies = roadmap_service.list_dependencies_for_initiative(
        tenant_id=tenant_id, initiative_id=initiative_id
    )

    plan_items = []
    for item in items:
        plan_items.append(
            {
                "id": item["id"],
                "title": item["title"],
                "item_type": item["item_type"],
                "goal_description": item.get("goal_description") or "",
                "sort_order": item.get("sort_order", 0),
                "target_date": item.get("target_date"),
                "sequencing_mode": item.get("sequencing_mode", "sequential"),
            }
        )

    plan_deps = []
    for dep in dependencies:
        plan_deps.append(
            {
                "from_item_id": dep["from_item_id"],
                "to_item_id": dep["to_item_id"],
                "dependency_type": dep["dependency_type"],
                "group_key": dep.get("group_key"),
            }
        )

    plan_criteria = []
    for item in items:
        for crit in criteria_service.list_criteria_for_item(
            tenant_id=tenant_id, item_id=item["id"]
        ):
            plan_criteria.append(
                {
                    "id": crit["id"],
                    "roadmap_item_id": crit["roadmap_item_id"],
                    "title": crit["title"],
                    "description": crit.get("description") or "",
                    "criterion_kind": crit["criterion_kind"],
                    "sort_order": crit.get("sort_order", 0),
                }
            )

    return {
        "items": plan_items,
        "dependencies": plan_deps,
        "criteria": plan_criteria,
    }


def list_plan_snapshots(
    *, tenant_id: str, initiative_id: str, limit: int = 20
) -> list[dict[str, Any]]:
    if not get_initiative(tenant_id=tenant_id, initiative_id=initiative_id):
        raise ValueError("Initiative nicht gefunden")

    conn = get_connection()
    try:
        with conn.cursor(cursor_factory=RealDictCursor) as cur:
            cur.execute(
                """
                SELECT id, tenant_id, initiative_id, roadmap_id, revision_number,
                       reason, plan_payload, created_by_user_id, created_at
                FROM roadmap_plan_snapshots
                WHERE tenant_id = %s AND initiative_id = %s
                ORDER BY revision_number DESC
                LIMIT %s
                """,
                (tenant_id, initiative_id, limit),
            )
            return [_serialize_snapshot(dict(r)) for r in cur.fetchall()]
    finally:
        conn.close()


def get_plan_snapshot(
    *, tenant_id: str, snapshot_id: str
) -> Optional[dict[str, Any]]:
    conn = get_connection()
    try:
        with conn.cursor(cursor_factory=RealDictCursor) as cur:
            cur.execute(
                """
                SELECT id, tenant_id, initiative_id, roadmap_id, revision_number,
                       reason, plan_payload, created_by_user_id, created_at
                FROM roadmap_plan_snapshots
                WHERE id = %s AND tenant_id = %s
                """,
                (snapshot_id, tenant_id),
            )
            row = cur.fetchone()
            return _serialize_snapshot(dict(row)) if row else None
    finally:
        conn.close()


def create_plan_snapshot(
    *,
    tenant_id: str,
    initiative_id: str,
    reason: str = "",
    user_id: Optional[str] = None,
) -> dict[str, Any]:
    if not get_initiative(tenant_id=tenant_id, initiative_id=initiative_id):
        raise ValueError("Initiative nicht gefunden")

    roadmap = roadmap_service.get_roadmap_for_initiative(
        tenant_id=tenant_id, initiative_id=initiative_id
    )
    if not roadmap:
        raise ValueError("Roadmap nicht gefunden")

    plan_payload = capture_plan_payload(tenant_id=tenant_id, initiative_id=initiative_id)
    reason = reason.strip()

    conn = get_connection()
    try:
        with conn.cursor(cursor_factory=RealDictCursor) as cur:
            cur.execute(
                """
                SELECT COALESCE(MAX(revision_number), 0) + 1 AS next_rev
                FROM roadmap_plan_snapshots
                WHERE tenant_id = %s AND initiative_id = %s
                """,
                (tenant_id, initiative_id),
            )
            revision_number = int(cur.fetchone()["next_rev"])

            cur.execute(
                """
                INSERT INTO roadmap_plan_snapshots (
                    tenant_id, initiative_id, roadmap_id, revision_number,
                    reason, plan_payload, created_by_user_id
                )
                VALUES (%s, %s, %s, %s, %s, %s, %s)
                RETURNING id, tenant_id, initiative_id, roadmap_id, revision_number,
                          reason, plan_payload, created_by_user_id, created_at
                """,
                (
                    tenant_id,
                    initiative_id,
                    roadmap["id"],
                    revision_number,
                    reason,
                    Json(plan_payload),
                    user_id,
                ),
            )
            row = _serialize_snapshot(dict(cur.fetchone()))
        conn.commit()
    finally:
        conn.close()

    log_audit(
        "roadmap_plan_snapshot.created",
        user_id=user_id,
        tenant_id=tenant_id,
        details={
            "snapshot_id": row["id"],
            "initiative_id": initiative_id,
            "revision_number": revision_number,
            "reason": reason or None,
        },
    )
    return row