"""Review service — tenant-scoped CRUD (AP0.9d)."""

from __future__ import annotations

from datetime import datetime
from typing import Any, Literal, Optional

from psycopg2.extras import RealDictCursor

from db import get_connection
from services.audit import log_audit
from services.initiatives import get_initiative

ReviewStatus = Literal["planned", "completed", "skipped"]

REVIEW_STATUSES = frozenset({"planned", "completed", "skipped"})

_REVIEW_COLUMNS = """
    id, tenant_id, initiative_id, action_id, milestone_id, title, summary,
    status, due_at, reviewed_by_actor_id, created_at, updated_at
"""


def _serialize_row(row: dict[str, Any]) -> dict[str, Any]:
    result = dict(row)
    for key in (
        "id",
        "tenant_id",
        "initiative_id",
        "action_id",
        "milestone_id",
        "reviewed_by_actor_id",
    ):
        if result.get(key):
            result[key] = str(result[key])
    for ts_key in ("created_at", "updated_at", "due_at"):
        if result.get(ts_key):
            result[ts_key] = result[ts_key].isoformat()
    return result


def _validate_status(status: str) -> None:
    if status not in REVIEW_STATUSES:
        raise ValueError(f"Ungültiger Review-Status: {status}")


def _actor_in_tenant(*, tenant_id: str, actor_id: str) -> bool:
    conn = get_connection()
    try:
        with conn.cursor() as cur:
            cur.execute(
                "SELECT 1 FROM actors WHERE id = %s AND tenant_id = %s AND is_active = TRUE",
                (actor_id, tenant_id),
            )
            return cur.fetchone() is not None
    finally:
        conn.close()


def _action_in_initiative(*, tenant_id: str, initiative_id: str, action_id: str) -> bool:
    conn = get_connection()
    try:
        with conn.cursor() as cur:
            cur.execute(
                """
                SELECT 1 FROM actions
                WHERE id = %s AND tenant_id = %s AND initiative_id = %s
                """,
                (action_id, tenant_id, initiative_id),
            )
            return cur.fetchone() is not None
    finally:
        conn.close()


def _milestone_in_initiative(
    *, tenant_id: str, initiative_id: str, milestone_id: str
) -> bool:
    conn = get_connection()
    try:
        with conn.cursor() as cur:
            cur.execute(
                """
                SELECT 1 FROM milestones
                WHERE id = %s AND tenant_id = %s AND initiative_id = %s
                """,
                (milestone_id, tenant_id, initiative_id),
            )
            return cur.fetchone() is not None
    finally:
        conn.close()


def create_review(
    *,
    tenant_id: str,
    initiative_id: str,
    title: str,
    summary: str = "",
    status: ReviewStatus = "planned",
    due_at: Optional[datetime] = None,
    action_id: Optional[str] = None,
    milestone_id: Optional[str] = None,
    reviewed_by_actor_id: Optional[str] = None,
    user_id: Optional[str] = None,
) -> dict[str, Any]:
    title = title.strip()
    if not title:
        raise ValueError("Titel ist erforderlich")
    _validate_status(status)
    if not get_initiative(tenant_id=tenant_id, initiative_id=initiative_id):
        raise ValueError("Initiative nicht gefunden")
    if action_id and not _action_in_initiative(
        tenant_id=tenant_id, initiative_id=initiative_id, action_id=action_id
    ):
        raise ValueError("Maßnahme gehört nicht zum Vorhaben")
    if milestone_id and not _milestone_in_initiative(
        tenant_id=tenant_id, initiative_id=initiative_id, milestone_id=milestone_id
    ):
        raise ValueError("Meilenstein gehört nicht zum Vorhaben")
    if reviewed_by_actor_id and not _actor_in_tenant(
        tenant_id=tenant_id, actor_id=reviewed_by_actor_id
    ):
        raise ValueError("Actor gehört nicht zum Tenant")

    conn = get_connection()
    try:
        with conn.cursor(cursor_factory=RealDictCursor) as cur:
            cur.execute(
                f"""
                INSERT INTO reviews (
                    tenant_id, initiative_id, action_id, milestone_id,
                    title, summary, status, due_at, reviewed_by_actor_id
                )
                VALUES (%s, %s, %s, %s, %s, %s, %s, %s, %s)
                RETURNING {_REVIEW_COLUMNS}
                """,
                (
                    tenant_id,
                    initiative_id,
                    action_id,
                    milestone_id,
                    title,
                    summary,
                    status,
                    due_at,
                    reviewed_by_actor_id,
                ),
            )
            row = _serialize_row(dict(cur.fetchone()))
        conn.commit()
    finally:
        conn.close()

    log_audit(
        "review.created",
        user_id=user_id,
        tenant_id=tenant_id,
        details={"review_id": row["id"], "initiative_id": initiative_id},
    )
    return row


def list_reviews_for_initiative(
    *, tenant_id: str, initiative_id: str
) -> 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(
                f"""
                SELECT {_REVIEW_COLUMNS}
                FROM reviews
                WHERE tenant_id = %s AND initiative_id = %s
                ORDER BY updated_at DESC, title
                """,
                (tenant_id, initiative_id),
            )
            return [_serialize_row(dict(r)) for r in cur.fetchall()]
    finally:
        conn.close()


def get_review(*, tenant_id: str, review_id: str) -> Optional[dict[str, Any]]:
    conn = get_connection()
    try:
        with conn.cursor(cursor_factory=RealDictCursor) as cur:
            cur.execute(
                f"""
                SELECT {_REVIEW_COLUMNS}
                FROM reviews
                WHERE id = %s AND tenant_id = %s
                """,
                (review_id, tenant_id),
            )
            row = cur.fetchone()
            return _serialize_row(dict(row)) if row else None
    finally:
        conn.close()


def update_review(
    *,
    tenant_id: str,
    review_id: str,
    user_id: Optional[str] = None,
    title: Optional[str] = None,
    summary: Optional[str] = None,
    status: Optional[ReviewStatus] = None,
    due_at: Optional[datetime] = None,
    clear_due_at: bool = False,
    action_id: Optional[str] = None,
    milestone_id: Optional[str] = None,
    clear_action_id: bool = False,
    clear_milestone_id: bool = False,
) -> Optional[dict[str, Any]]:
    existing = get_review(tenant_id=tenant_id, review_id=review_id)
    if not existing:
        return None

    old_status = existing["status"]
    updates: list[str] = []
    params: list[Any] = []

    if title is not None:
        title = title.strip()
        if not title:
            raise ValueError("Titel ist erforderlich")
        updates.append("title = %s")
        params.append(title)
    if summary is not None:
        updates.append("summary = %s")
        params.append(summary)
    if status is not None:
        _validate_status(status)
        updates.append("status = %s")
        params.append(status)
    if clear_due_at:
        updates.append("due_at = NULL")
    elif due_at is not None:
        updates.append("due_at = %s")
        params.append(due_at)
    if clear_action_id:
        updates.append("action_id = NULL")
    elif action_id is not None:
        if not _action_in_initiative(
            tenant_id=tenant_id,
            initiative_id=existing["initiative_id"],
            action_id=action_id,
        ):
            raise ValueError("Maßnahme gehört nicht zum Vorhaben")
        updates.append("action_id = %s")
        params.append(action_id)
    if clear_milestone_id:
        updates.append("milestone_id = NULL")
    elif milestone_id is not None:
        if not _milestone_in_initiative(
            tenant_id=tenant_id,
            initiative_id=existing["initiative_id"],
            milestone_id=milestone_id,
        ):
            raise ValueError("Meilenstein gehört nicht zum Vorhaben")
        updates.append("milestone_id = %s")
        params.append(milestone_id)

    if not updates:
        return existing

    updates.append("updated_at = NOW()")
    params.extend([review_id, tenant_id])

    conn = get_connection()
    try:
        with conn.cursor(cursor_factory=RealDictCursor) as cur:
            cur.execute(
                f"""
                UPDATE reviews
                SET {", ".join(updates)}
                WHERE id = %s AND tenant_id = %s
                RETURNING {_REVIEW_COLUMNS}
                """,
                params,
            )
            row = cur.fetchone()
            if not row:
                return None
            result = _serialize_row(dict(row))
        conn.commit()
    finally:
        conn.close()

    log_audit(
        "review.updated",
        user_id=user_id,
        tenant_id=tenant_id,
        details={"review_id": review_id},
    )
    if status is not None and status != old_status:
        log_audit(
            "review.status_changed",
            user_id=user_id,
            tenant_id=tenant_id,
            details={
                "review_id": review_id,
                "from_status": old_status,
                "to_status": status,
            },
        )
        from services.operating_transitions import after_review_status_change

        after_review_status_change(
            tenant_id=tenant_id,
            review_id=review_id,
            action_id=result.get("action_id"),
            old_status=old_status,
            new_status=status,
            user_id=user_id,
        )
    return result


def delete_review(
    *,
    tenant_id: str,
    review_id: str,
    user_id: Optional[str] = None,
) -> bool:
    conn = get_connection()
    try:
        with conn.cursor() as cur:
            cur.execute(
                "DELETE FROM reviews WHERE id = %s AND tenant_id = %s RETURNING id",
                (review_id, tenant_id),
            )
            deleted = cur.fetchone() is not None
        conn.commit()
    finally:
        conn.close()

    if deleted:
        log_audit(
            "review.deleted",
            user_id=user_id,
            tenant_id=tenant_id,
            details={"review_id": review_id},
        )
    return deleted