"""SteeringContext write service — AP1.0."""

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 steering.lifecycle.states import validate_lifecycle_state

DEFAULT_METHOD_KEY = "generic_operating"
DEFAULT_METHOD_VERSION = "0.1.0"


def _serialize_row(row: dict[str, Any]) -> dict[str, Any]:
    result = dict(row)
    for key in ("id", "tenant_id", "initiative_id"):
        if result.get(key):
            result[key] = str(result[key])
    if result.get("created_at"):
        result["created_at"] = result["created_at"].isoformat()
    if result.get("updated_at"):
        result["updated_at"] = result["updated_at"].isoformat()
    if isinstance(result.get("lifecycle_metadata"), dict):
        pass
    elif result.get("lifecycle_metadata") is not None:
        result["lifecycle_metadata"] = dict(result["lifecycle_metadata"])
    return result


def _infer_initial_lifecycle_state(*, tenant_id: str, initiative_id: str) -> str:
    initiative = get_initiative(tenant_id=tenant_id, initiative_id=initiative_id)
    if not initiative:
        return "intake"
    if initiative["status"] in ("completed", "archived"):
        return "closure"

    conn = get_connection()
    try:
        with conn.cursor(cursor_factory=RealDictCursor) as cur:
            cur.execute(
                """
                SELECT 1 FROM actions
                WHERE tenant_id = %s AND initiative_id = %s
                  AND status IN (
                      'open', 'ready', 'in_progress', 'blocked', 'review_required'
                  )
                LIMIT 1
                """,
                (tenant_id, initiative_id),
            )
            if cur.fetchone():
                return "action_selection"

            cur.execute(
                """
                SELECT 1 FROM backlog_items
                WHERE tenant_id = %s AND initiative_id = %s
                  AND status IN ('new', 'triaged', 'accepted')
                LIMIT 1
                """,
                (tenant_id, initiative_id),
            )
            if cur.fetchone():
                return "structure_setup"
    finally:
        conn.close()

    return "planning"


def get_steering_context(
    *, tenant_id: str, initiative_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, method_key, method_version,
                       lifecycle_state, lifecycle_metadata, created_at, updated_at
                FROM steering_contexts
                WHERE tenant_id = %s AND initiative_id = %s
                """,
                (tenant_id, initiative_id),
            )
            row = cur.fetchone()
            return _serialize_row(dict(row)) if row else None
    finally:
        conn.close()


def ensure_steering_context(
    *,
    tenant_id: str,
    initiative_id: str,
    initial_state: Optional[str] = None,
    user_id: Optional[str] = None,
) -> dict[str, Any]:
    existing = get_steering_context(tenant_id=tenant_id, initiative_id=initiative_id)
    if existing:
        return existing

    if not get_initiative(tenant_id=tenant_id, initiative_id=initiative_id):
        raise ValueError("Vorhaben nicht gefunden")

    state = initial_state or _infer_initial_lifecycle_state(
        tenant_id=tenant_id, initiative_id=initiative_id
    )
    validate_lifecycle_state(state)

    conn = get_connection()
    try:
        with conn.cursor(cursor_factory=RealDictCursor) as cur:
            cur.execute(
                """
                INSERT INTO steering_contexts (
                    tenant_id, initiative_id, method_key, method_version,
                    lifecycle_state, lifecycle_metadata
                )
                VALUES (%s, %s, %s, %s, %s, %s)
                RETURNING id, tenant_id, initiative_id, method_key, method_version,
                          lifecycle_state, lifecycle_metadata, created_at, updated_at
                """,
                (
                    tenant_id,
                    initiative_id,
                    DEFAULT_METHOD_KEY,
                    DEFAULT_METHOD_VERSION,
                    state,
                    Json({}),
                ),
            )
            row = _serialize_row(dict(cur.fetchone()))
        conn.commit()
    finally:
        conn.close()

    log_audit(
        "steering_context.created",
        user_id=user_id,
        tenant_id=tenant_id,
        details={"initiative_id": initiative_id, "lifecycle_state": state},
    )
    return row


def update_lifecycle_state(
    *,
    tenant_id: str,
    initiative_id: str,
    lifecycle_state: str,
    user_id: Optional[str] = None,
    reason: str = "",
    from_state: Optional[str] = None,
) -> dict[str, Any]:
    validate_lifecycle_state(lifecycle_state)
    conn = get_connection()
    try:
        with conn.cursor(cursor_factory=RealDictCursor) as cur:
            cur.execute(
                """
                UPDATE steering_contexts
                SET lifecycle_state = %s, updated_at = NOW()
                WHERE tenant_id = %s AND initiative_id = %s
                RETURNING id, tenant_id, initiative_id, method_key, method_version,
                          lifecycle_state, lifecycle_metadata, created_at, updated_at
                """,
                (lifecycle_state, tenant_id, initiative_id),
            )
            row = cur.fetchone()
            if not row:
                raise ValueError("SteeringContext nicht gefunden")
            result = _serialize_row(dict(row))
        conn.commit()
    finally:
        conn.close()

    log_audit(
        "steering_context.lifecycle_transition",
        user_id=user_id,
        tenant_id=tenant_id,
        details={
            "initiative_id": initiative_id,
            "from_state": from_state,
            "to_state": lifecycle_state,
            "reason": reason,
        },
    )
    return result


def update_method_key(
    *,
    tenant_id: str,
    initiative_id: str,
    method_key: str,
    user_id: Optional[str] = None,
) -> dict[str, Any]:
    from steering.methods.registry import get_method

    method = get_method(method_key)
    if not method:
        raise ValueError(f"Unbekannte Methode: {method_key}")

    existing = get_steering_context(tenant_id=tenant_id, initiative_id=initiative_id)
    if not existing:
        raise ValueError("SteeringContext nicht gefunden")

    conn = get_connection()
    try:
        with conn.cursor(cursor_factory=RealDictCursor) as cur:
            cur.execute(
                """
                UPDATE steering_contexts
                SET method_key = %s, method_version = %s, updated_at = NOW()
                WHERE tenant_id = %s AND initiative_id = %s
                RETURNING id, tenant_id, initiative_id, method_key, method_version,
                          lifecycle_state, lifecycle_metadata, created_at, updated_at
                """,
                (method.key, method.version, tenant_id, initiative_id),
            )
            row = cur.fetchone()
            if not row:
                raise ValueError("SteeringContext nicht gefunden")
            result = _serialize_row(dict(row))
        conn.commit()
    finally:
        conn.close()

    log_audit(
        "steering_context.method_changed",
        user_id=user_id,
        tenant_id=tenant_id,
        details={
            "initiative_id": initiative_id,
            "from_method": existing["method_key"],
            "to_method": method_key,
        },
    )
    return result


def create_context_for_new_initiative(
    *,
    tenant_id: str,
    initiative_id: str,
    user_id: Optional[str] = None,
) -> dict[str, Any]:
    return ensure_steering_context(
        tenant_id=tenant_id,
        initiative_id=initiative_id,
        initial_state="intake",
        user_id=user_id,
    )