"""
知识图谱元数据：列表/详情与知识库一致的可见性与 RBAC。
"""
from __future__ import annotations

from typing import Any, Dict, List, Optional, Tuple

import asyncpg

from core.graph_metadata import graph_table_sql
from core.permissions import can_manage_graph, can_view_graph, get_managed_dept_ids
from models.graph_metadata import GraphRecord
from models.user import User
from logger.logging import get_logger

logger = get_logger(__name__)


class KnowledgeGraphService:
    @staticmethod
    def _validate_visibility(v: str) -> str:
        if v not in ("private", "department", "enterprise"):
            raise ValueError("visibility 必须是 private、department 或 enterprise")
        return v

    @staticmethod
    def _row_to_graph_record(row: Dict[str, Any]) -> GraphRecord:
        return GraphRecord(
            id=int(row["id"]),
            user_id=int(row["user_id"]),
            enterprise_id=row.get("enterprise_id"),
            department_id=row.get("department_id"),
            creator_id=row.get("creator_id"),
            visibility=(row.get("visibility") or "private"),
        )

    @staticmethod
    async def enrich_graph_for_response(
        conn: asyncpg.Connection,
        raw: Dict[str, Any],
        viewer: User,
    ) -> Dict[str, Any]:
        """补充创建者、部门、是否本人、是否可管理。"""
        data = dict(raw)
        t = graph_table_sql()
        gid = raw.get("id")
        row = await conn.fetchrow(
            f"""
            SELECT u.username AS creator_username,
                   COALESCE(NULLIF(TRIM(u.display_name), ''), u.username) AS creator_display_name,
                   d.name AS department_name
            FROM {t} g
            LEFT JOIN user_list u ON u.id = g.creator_id
            LEFT JOIN department d ON d.id = g.department_id
            WHERE g.id = $1
            """,
            gid,
        )
        if row:
            data["creator_username"] = row["creator_username"]
            data["creator_display_name"] = row["creator_display_name"]
            data["department_name"] = row["department_name"]
        else:
            data["creator_username"] = None
            data["creator_display_name"] = None
            data["department_name"] = None

        gr = KnowledgeGraphService._row_to_graph_record(data)
        cid = gr.creator_id
        uid = viewer.id
        data["is_mine"] = bool(
            uid is not None
            and (
                (cid is not None and cid == uid)
                or (cid is None and int(data.get("user_id") or 0) == uid)
            )
        )
        data["can_manage"] = can_manage_graph(viewer, gr)
        return data

    @staticmethod
    async def list_visible_graphs(
        conn: asyncpg.Connection,
        user: User,
        page: int = 1,
        page_size: int = 20,
    ) -> Tuple[List[Dict[str, Any]], int]:
        t = graph_table_sql()
        enterprise_id = user.enterprise_id
        if enterprise_id is None:
            return [], 0

        offset = (page - 1) * page_size
        role = user.role or "employee"
        dept_id = user.department_id
        uid = user.id

        # leader 需要获取本部门及所有子孙部门 ID，与知识库列表保持一致
        managed_dept_ids: List[int] = []
        if role == "leader" and dept_id is not None:
            managed_dept_ids = await get_managed_dept_ids(conn, user)

        where_sql = """
            g.enterprise_id = $1
            AND (
                $2::text = 'admin'
                OR g.creator_id = $3
                OR ($2::text = 'leader' AND g.department_id IS NOT NULL AND g.department_id = ANY($4::int[]))
                OR (g.visibility = 'department' AND g.department_id IS NOT NULL AND g.department_id = $5)
                OR (g.visibility = 'enterprise')
            )
        """

        total = await conn.fetchval(
            f"""
            SELECT COUNT(*) FROM {t} g
            WHERE {where_sql}
            """,
            enterprise_id,
            role,
            uid,
            managed_dept_ids,
            dept_id,
        )

        rows = await conn.fetch(
            f"""
            SELECT g.id, g.user_id, g.enterprise_id, g.department_id, g.creator_id, g.visibility,
                   g.name, g.description, g.csv_file_name, g.node_count, g.edge_count, g.neo4j_graph_id,
                   g.graph_type, g.build_status, g.build_error, g.rag_chunk_count,
                   g.created_at, g.updated_at,
                   u.username AS creator_username,
                   COALESCE(NULLIF(TRIM(u.display_name), ''), u.username) AS creator_display_name,
                   d.name AS department_name
            FROM {t} g
            LEFT JOIN user_list u ON u.id = g.creator_id
            LEFT JOIN department d ON d.id = g.department_id
            WHERE {where_sql}
            ORDER BY g.created_at DESC
            LIMIT $6 OFFSET $7
            """,
            enterprise_id,
            role,
            uid,
            managed_dept_ids,
            dept_id,
            page_size,
            offset,
        )

        items: List[Dict[str, Any]] = []
        for r in rows:
            d = dict(r)
            gr = KnowledgeGraphService._row_to_graph_record(d)
            cid = gr.creator_id
            d["is_mine"] = bool(
                uid is not None
                and (
                    (cid is not None and cid == uid)
                    or (cid is None and d.get("user_id") == uid)
                )
            )
            d["can_manage"] = can_manage_graph(user, gr)
            items.append(d)
        return items, int(total or 0)

    @staticmethod
    async def fetch_graph_by_id(conn: asyncpg.Connection, graph_pk: int) -> Optional[Dict[str, Any]]:
        t = graph_table_sql()
        row = await conn.fetchrow(
            f"""
            SELECT * FROM {t}
            WHERE id = $1
            """,
            graph_pk,
        )
        return dict(row) if row else None

    @staticmethod
    async def get_graph_for_viewer(
        conn: asyncpg.Connection,
        graph_pk: int,
        user: User,
    ) -> Optional[Dict[str, Any]]:
        raw = await KnowledgeGraphService.fetch_graph_by_id(conn, graph_pk)
        if raw is None:
            return None
        try:
            gr = KnowledgeGraphService._row_to_graph_record(raw)
        except Exception:
            return None
        if not await can_view_graph(conn, user, gr):
            return None
        return await KnowledgeGraphService.enrich_graph_for_response(conn, raw, user)