"""
PostgreSQL requirement 存储封装

用于存储和检索需求数据，支持向量检索。
表名：requirement（从 requirement_table 迁移）
"""

import os
import json
import psycopg2
from psycopg2.extras import RealDictCursor
from typing import List, Dict, Optional
from dotenv import load_dotenv
from knowhub.knowhub_db.cascade import cascade_delete

load_dotenv()

# 关联字段子查询。knowledge 边暴露两种视图：knowledge_ids（扁平）+ knowledge_links（含 type）
_REL_SUBQUERY = """
    (SELECT COALESCE(json_agg(rc.capability_id), '[]'::json)
     FROM requirement_capability rc WHERE rc.requirement_id = requirement.id) AS capability_ids,
    (SELECT COALESCE(json_agg(rk.knowledge_id), '[]'::json)
     FROM requirement_knowledge rk WHERE rk.requirement_id = requirement.id) AS knowledge_ids,
    (SELECT COALESCE(json_agg(json_build_object(
        'id', rk2.knowledge_id, 'relation_type', rk2.relation_type
     )), '[]'::json)
     FROM requirement_knowledge rk2 WHERE rk2.requirement_id = requirement.id) AS knowledge_links,
    (SELECT COALESCE(json_agg(rr.resource_id), '[]'::json)
     FROM requirement_resource rr WHERE rr.requirement_id = requirement.id) AS resource_ids,
    (SELECT COALESCE(json_agg(rs.strategy_id), '[]'::json)
     FROM requirement_strategy rs WHERE rs.requirement_id = requirement.id) AS strategy_ids,
    (SELECT COALESCE(json_agg(rp.itemset_id), '[]'::json)
     FROM requirement_pattern rp WHERE rp.requirement_id = requirement.id) AS pattern_ids,
    (SELECT COALESCE(json_agg(rn.node_id), '[]'::json)
     FROM requirement_node rn WHERE rn.requirement_id = requirement.id) AS node_ids
"""

_BASE_FIELDS = "id, description, source_nodes, status, match_result, version"

_SELECT_FIELDS = f"{_BASE_FIELDS}, {_REL_SUBQUERY}"


def _normalize_links(data: Dict, links_key: str, ids_key: str, default_type: str):
    """两种输入格式统一：{links_key: [{id, relation_type}]} 或 {ids_key: [id]}"""
    if links_key in data and data[links_key] is not None:
        out = []
        for item in data[links_key]:
            if isinstance(item, dict):
                out.append((item['id'], item.get('relation_type', default_type)))
            else:
                out.append((item, default_type))
        return out
    if ids_key in data and data[ids_key] is not None:
        return [(i, default_type) for i in data[ids_key]]
    return None


class PostgreSQLRequirementStore:
    def __init__(self):
        """初始化 PostgreSQL 连接"""
        self.conn = psycopg2.connect(
            host=os.getenv('KNOWHUB_DB'),
            port=int(os.getenv('KNOWHUB_PORT', 5432)),
            user=os.getenv('KNOWHUB_USER'),
            password=os.getenv('KNOWHUB_PASSWORD'),
            database=os.getenv('KNOWHUB_DB_NAME')
        )
        self.conn.autocommit = True
        print(f"[PostgreSQL Requirement] 已连接到远程数据库: {os.getenv('KNOWHUB_DB')}")

    def _reconnect(self):
        self.conn = psycopg2.connect(
            host=os.getenv('KNOWHUB_DB'),
            port=int(os.getenv('KNOWHUB_PORT', 5432)),
            user=os.getenv('KNOWHUB_USER'),
            password=os.getenv('KNOWHUB_PASSWORD'),
            database=os.getenv('KNOWHUB_DB_NAME')
        )
        self.conn.autocommit = True

    def _ensure_connection(self):
        if self.conn.closed != 0:
            self._reconnect()
        else:
            try:
                c = self.conn.cursor()
                c.execute("SELECT 1")
                c.close()
            except (psycopg2.OperationalError, psycopg2.InterfaceError):
                self._reconnect()

    def _get_cursor(self):
        self._ensure_connection()
        return self.conn.cursor(cursor_factory=RealDictCursor)

    def insert_or_update(self, requirement: Dict):
        """插入或更新需求记录。AnalyticDB beam 表不支持 ON CONFLICT UPDATE 当含 ALTER 新增列，改用 DELETE+INSERT。"""
        cursor = self._get_cursor()
        try:
            cursor.execute("DELETE FROM requirement WHERE id = %s", (requirement['id'],))
            cursor.execute("""
                INSERT INTO requirement (
                    id, description, source_nodes, status, match_result, embedding, version
                ) VALUES (%s, %s, %s, %s, %s, %s, %s)
            """, (
                requirement['id'],
                requirement.get('description', ''),
                json.dumps(requirement.get('source_nodes', [])),
                requirement.get('status', '未满足'),
                requirement.get('match_result', ''),
                requirement.get('embedding'),
                requirement.get('version', 'v0'),
            ))
            # 写入关联表
            req_id = requirement['id']
            if 'capability_ids' in requirement:
                cursor.execute("DELETE FROM requirement_capability WHERE requirement_id = %s", (req_id,))
                for cap_id in requirement['capability_ids']:
                    cursor.execute(
                        "INSERT INTO requirement_capability (requirement_id, capability_id) VALUES (%s, %s) ON CONFLICT DO NOTHING",
                        (req_id, cap_id))
            k_links = _normalize_links(requirement, 'knowledge_links', 'knowledge_ids', 'related')
            if k_links is not None:
                cursor.execute("DELETE FROM requirement_knowledge WHERE requirement_id = %s", (req_id,))
                for kid, rtype in k_links:
                    cursor.execute(
                        "INSERT INTO requirement_knowledge (requirement_id, knowledge_id, relation_type) "
                        "VALUES (%s, %s, %s) ON CONFLICT DO NOTHING",
                        (req_id, kid, rtype))
            if 'resource_ids' in requirement and requirement['resource_ids'] is not None:
                cursor.execute("DELETE FROM requirement_resource WHERE requirement_id = %s", (req_id,))
                for rid in requirement['resource_ids']:
                    cursor.execute(
                        "INSERT INTO requirement_resource (requirement_id, resource_id) VALUES (%s, %s) ON CONFLICT DO NOTHING",
                        (req_id, rid))
            if 'strategy_ids' in requirement and requirement['strategy_ids'] is not None:
                cursor.execute("DELETE FROM requirement_strategy WHERE requirement_id = %s", (req_id,))
                for sid in requirement['strategy_ids']:
                    cursor.execute(
                        "INSERT INTO requirement_strategy (requirement_id, strategy_id) VALUES (%s, %s) ON CONFLICT DO NOTHING",
                        (req_id, sid))
            self.conn.commit()
        finally:
            cursor.close()

    def get_by_id(self, req_id: str) -> Optional[Dict]:
        """根据 ID 获取需求"""
        from knowhub.knowhub_db.version_context import req_version_where
        cursor = self._get_cursor()
        try:
            vf, vp = req_version_where()
            cursor.execute(f"""
                SELECT {_SELECT_FIELDS}
                FROM requirement WHERE id = %s AND {vf}
            """, (req_id, *vp))
            result = cursor.fetchone()
            return self._format_result(result) if result else None
        finally:
            cursor.close()

    def search(self, query_embedding: List[float], limit: int = 10) -> List[Dict]:
        """向量检索需求"""
        from knowhub.knowhub_db.version_context import req_version_where
        cursor = self._get_cursor()
        try:
            vf, vp = req_version_where()
            cursor.execute(f"""
                SELECT {_SELECT_FIELDS},
                       1 - (embedding <=> %s::real[]) as score
                FROM requirement
                WHERE embedding IS NOT NULL AND {vf}
                ORDER BY embedding <=> %s::real[]
                LIMIT %s
            """, (query_embedding, *vp, query_embedding, limit))
            results = cursor.fetchall()
            return [self._format_result(r) for r in results]
        finally:
            cursor.close()

    def list_all(self, limit: int = 100, offset: int = 0, status: Optional[str] = None) -> List[Dict]:
        """列出需求"""
        from knowhub.knowhub_db.version_context import req_version_where
        cursor = self._get_cursor()
        try:
            vf, vp = req_version_where()
            if status:
                cursor.execute(f"""
                    SELECT {_SELECT_FIELDS}
                    FROM requirement
                    WHERE status = %s AND {vf}
                    ORDER BY id
                    LIMIT %s OFFSET %s
                """, (status, *vp, limit, offset))
            else:
                cursor.execute(f"""
                    SELECT {_SELECT_FIELDS}
                    FROM requirement
                    WHERE {vf}
                    ORDER BY id
                    LIMIT %s OFFSET %s
                """, (*vp, limit, offset))
            results = cursor.fetchall()
            return [self._format_result(r) for r in results]
        finally:
            cursor.close()

    def update(self, req_id: str, updates: Dict):
        """更新需求字段"""
        cursor = self._get_cursor()
        try:
            # 分离关联字段
            cap_ids = updates.pop('capability_ids', None)
            strategy_ids = updates.pop('strategy_ids', None)
            rel_data = {}
            for k in ('knowledge_ids', 'knowledge_links', 'resource_ids'):
                if k in updates:
                    rel_data[k] = updates.pop(k)

            if updates:
                set_parts = []
                params = []
                json_fields = ('source_nodes',)
                for key, value in updates.items():
                    set_parts.append(f"{key} = %s")
                    if key in json_fields:
                        params.append(json.dumps(value))
                    else:
                        params.append(value)
                params.append(req_id)
                cursor.execute(
                    f"UPDATE requirement SET {', '.join(set_parts)} WHERE id = %s",
                    params
                )

            if cap_ids is not None:
                cursor.execute("DELETE FROM requirement_capability WHERE requirement_id = %s", (req_id,))
                for cap_id in cap_ids:
                    cursor.execute(
                        "INSERT INTO requirement_capability (requirement_id, capability_id) VALUES (%s, %s) ON CONFLICT DO NOTHING",
                        (req_id, cap_id))

            k_links = _normalize_links(rel_data, 'knowledge_links', 'knowledge_ids', 'related')
            if k_links is not None:
                cursor.execute("DELETE FROM requirement_knowledge WHERE requirement_id = %s", (req_id,))
                for kid, rtype in k_links:
                    cursor.execute(
                        "INSERT INTO requirement_knowledge (requirement_id, knowledge_id, relation_type) "
                        "VALUES (%s, %s, %s) ON CONFLICT DO NOTHING",
                        (req_id, kid, rtype))

            if 'resource_ids' in rel_data and rel_data['resource_ids'] is not None:
                cursor.execute("DELETE FROM requirement_resource WHERE requirement_id = %s", (req_id,))
                for rid in rel_data['resource_ids']:
                    cursor.execute(
                        "INSERT INTO requirement_resource (requirement_id, resource_id) VALUES (%s, %s) ON CONFLICT DO NOTHING",
                        (req_id, rid))

            if strategy_ids is not None:
                cursor.execute("DELETE FROM requirement_strategy WHERE requirement_id = %s", (req_id,))
                for sid in strategy_ids:
                    cursor.execute(
                        "INSERT INTO requirement_strategy (requirement_id, strategy_id) VALUES (%s, %s) ON CONFLICT DO NOTHING",
                        (req_id, sid))

            self.conn.commit()
        finally:
            cursor.close()

    def add_knowledge(self, req_id: str, knowledge_id: str, relation_type: str = 'related'):
        """增量挂接 requirement-knowledge 边"""
        cursor = self._get_cursor()
        try:
            cursor.execute(
                "INSERT INTO requirement_knowledge (requirement_id, knowledge_id, relation_type) "
                "VALUES (%s, %s, %s) ON CONFLICT DO NOTHING",
                (req_id, knowledge_id, relation_type))
            self.conn.commit()
        finally:
            cursor.close()

    def add_resource(self, req_id: str, resource_id: str):
        """增量挂接 requirement-resource 边"""
        cursor = self._get_cursor()
        try:
            cursor.execute(
                "INSERT INTO requirement_resource (requirement_id, resource_id) VALUES (%s, %s) ON CONFLICT DO NOTHING",
                (req_id, resource_id))
            self.conn.commit()
        finally:
            cursor.close()

    def add_strategy(self, req_id: str, strategy_id: str):
        """增量挂接 requirement-strategy 边（该 strategy 满足此 requirement）"""
        cursor = self._get_cursor()
        try:
            cursor.execute(
                "INSERT INTO requirement_strategy (requirement_id, strategy_id) VALUES (%s, %s) ON CONFLICT DO NOTHING",
                (req_id, strategy_id))
            self.conn.commit()
        finally:
            cursor.close()

    def delete(self, req_id: str):
        """删除需求及其关联表记录"""
        cursor = self._get_cursor()
        try:
            cascade_delete(cursor, 'requirement', req_id)
            self.conn.commit()
        finally:
            cursor.close()

    def count(self, status: Optional[str] = None) -> int:
        """统计需求总数"""
        from knowhub.knowhub_db.version_context import req_version_where
        cursor = self._get_cursor()
        try:
            vf, vp = req_version_where()
            if status:
                cursor.execute(f"SELECT COUNT(*) as count FROM requirement WHERE status = %s AND {vf}",
                               (status, *vp))
            else:
                cursor.execute(f"SELECT COUNT(*) as count FROM requirement WHERE {vf}", vp)
            return cursor.fetchone()['count']
        finally:
            cursor.close()

    def _format_result(self, row: Dict) -> Dict:
        """格式化查询结果"""
        if not row:
            return None
        result = dict(row)
        if 'source_nodes' in result and isinstance(result['source_nodes'], str):
            result['source_nodes'] = json.loads(result['source_nodes'])
        # 关联字段（来自 junction table 子查询）
        for field in ('capability_ids', 'knowledge_ids', 'resource_ids', 'strategy_ids', 'knowledge_links', 'pattern_ids', 'node_ids'):
            if field in result and isinstance(result[field], str):
                result[field] = json.loads(result[field])
            elif field in result and result[field] is None:
                result[field] = []
        return result

    def close(self):
        if self.conn:
            self.conn.close()