"""
PostgreSQL 存储封装（替代 Milvus）

使用远程 PostgreSQL + pgvector/fastann 存储知识数据
"""

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

load_dotenv()

# 关联字段的子查询（从 junction table 读取）
# 对于带 relation_type 的 *_knowledge 边，同时暴露两种视图：
#   - *_ids       : 扁平 ID 列表（向后兼容，不含 type）
#   - *_links     : [{id, relation_type}]（含 type）
_REL_SUBQUERIES = """
    (SELECT COALESCE(json_agg(rk.requirement_id), '[]'::json)
     FROM requirement_knowledge rk WHERE rk.knowledge_id = knowledge.id) AS requirement_ids,
    (SELECT COALESCE(json_agg(json_build_object(
        'id', rk2.requirement_id, 'relation_type', rk2.relation_type
     )), '[]'::json)
     FROM requirement_knowledge rk2 WHERE rk2.knowledge_id = knowledge.id) AS requirement_links,
    (SELECT COALESCE(json_agg(ck.capability_id), '[]'::json)
     FROM capability_knowledge ck WHERE ck.knowledge_id = knowledge.id) AS capability_ids,
    (SELECT COALESCE(json_agg(json_build_object(
        'id', ck2.capability_id, 'relation_type', ck2.relation_type
     )), '[]'::json)
     FROM capability_knowledge ck2 WHERE ck2.knowledge_id = knowledge.id) AS capability_links,
    (SELECT COALESCE(json_agg(tk.tool_id), '[]'::json)
     FROM tool_knowledge tk WHERE tk.knowledge_id = knowledge.id) AS tool_ids,
    (SELECT COALESCE(json_agg(json_build_object(
        'id', tk2.tool_id, 'relation_type', tk2.relation_type
     )), '[]'::json)
     FROM tool_knowledge tk2 WHERE tk2.knowledge_id = knowledge.id) AS tool_links,
    (SELECT COALESCE(json_agg(kr.resource_id), '[]'::json)
     FROM knowledge_resource kr WHERE kr.knowledge_id = knowledge.id) AS resource_ids,
    (SELECT COALESCE(json_agg(json_build_object(
        'target_id', krel.target_id, 'relation_type', krel.relation_type
     )), '[]'::json)
     FROM knowledge_relation krel WHERE krel.source_id = knowledge.id) AS relations
"""

# 基础字段（不含 embedding）
_BASE_FIELDS = (
    "id, message_id, task, content, types, tags, tag_keys, "
    "scopes, owner, source, eval, "
    "created_at, updated_at, status"
)

# 完整 SELECT（含关联子查询）
_SELECT_FIELDS = f"{_BASE_FIELDS}, {_REL_SUBQUERIES}"

# 含 embedding 的 SELECT
_SELECT_FIELDS_WITH_EMB = f"task_embedding, content_embedding, {_SELECT_FIELDS}"


def _normalize_links(data: Dict, links_key: str, ids_key: str, default_type: str):
    """
    统一两种输入格式：
    - {links_key: [{id, relation_type}, ...]}  → 使用指定 type
    - {ids_key: [id1, id2, ...]}               → 使用 default_type
    两个 key 都没有返回 None（不更新）
    """
    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 PostgreSQLStore:
    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] 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):
        """获取游标"""
        self._ensure_connection()
        return self.conn.cursor(cursor_factory=RealDictCursor)

    def insert(self, knowledge: Dict):
        """插入单条知识"""
        cursor = self._get_cursor()
        try:
            cursor.execute("""
                INSERT INTO knowledge (
                    id, task_embedding, content_embedding, message_id, task, content, types, tags,
                    tag_keys, scopes, owner, source, eval,
                    created_at, updated_at, status
                ) VALUES (%s, %s, %s, %s, %s, %s, %s, %s, %s, %s, %s, %s, %s, %s, %s, %s)
            """, (
                knowledge['id'],
                knowledge.get('task_embedding') or knowledge.get('embedding'),
                knowledge.get('content_embedding'),
                knowledge['message_id'],
                knowledge['task'],
                knowledge['content'],
                knowledge.get('types', []),
                json.dumps(knowledge.get('tags', {})),
                knowledge.get('tag_keys', []),
                knowledge.get('scopes', []),
                knowledge['owner'],
                json.dumps(knowledge.get('source', {})),
                json.dumps(knowledge.get('eval', {})),
                knowledge['created_at'],
                knowledge['updated_at'],
                knowledge.get('status', 'approved'),
            ))
            # 写入关联表
            kid = knowledge['id']
            req_links = _normalize_links(knowledge, 'requirement_links', 'requirement_ids', 'related') or []
            for req_id, rtype in req_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))
            cap_links = _normalize_links(knowledge, 'capability_links', 'capability_ids', 'related') or []
            for cap_id, rtype in cap_links:
                cursor.execute(
                    "INSERT INTO capability_knowledge (capability_id, knowledge_id, relation_type) "
                    "VALUES (%s, %s, %s) ON CONFLICT DO NOTHING",
                    (cap_id, kid, rtype))
            tool_links = _normalize_links(knowledge, 'tool_links', 'tool_ids', 'related') or []
            for tool_id, rtype in tool_links:
                cursor.execute(
                    "INSERT INTO tool_knowledge (tool_id, knowledge_id, relation_type) "
                    "VALUES (%s, %s, %s) ON CONFLICT DO NOTHING",
                    (tool_id, kid, rtype))
            for res_id in knowledge.get('resource_ids', []):
                cursor.execute(
                    "INSERT INTO knowledge_resource (knowledge_id, resource_id) VALUES (%s, %s) ON CONFLICT DO NOTHING",
                    (kid, res_id))
            self.conn.commit()
        finally:
            cursor.close()

    def _apply_relation_filters(self, where_clause: str, relation_filters: Optional[Dict[str, str]], params: list) -> str:
        if not relation_filters:
            return where_clause
            
        rel_clauses = []
        for k, v in relation_filters.items():
            if not v: continue
            if k == 'requirement_id':
                rel_clauses.append("EXISTS (SELECT 1 FROM requirement_knowledge rk WHERE rk.knowledge_id = knowledge.id AND rk.requirement_id = %s)")
                params.append(v)
            elif k == 'capability_id':
                rel_clauses.append("EXISTS (SELECT 1 FROM capability_knowledge ck WHERE ck.knowledge_id = knowledge.id AND ck.capability_id = %s)")
                params.append(v)
            elif k == 'tool_id':
                rel_clauses.append("EXISTS (SELECT 1 FROM tool_knowledge tk WHERE tk.knowledge_id = knowledge.id AND tk.tool_id = %s)")
                params.append(v)
                
        if not rel_clauses:
            return where_clause
            
        rel_where = " AND ".join(rel_clauses)
        if where_clause.strip():
            return f"{where_clause} AND {rel_where}"
        else:
            return f"WHERE {rel_where}"

    def search(self, query_embedding: List[float], filters: Optional[str] = None, limit: int = 10, relation_filters: Optional[Dict[str, str]] = None) -> List[Dict]:
        """向量检索（使用余弦相似度）"""
        cursor = self._get_cursor()
        try:
            where_clause = self._build_where_clause(filters) if filters else ""
            params = []
            where_clause = self._apply_relation_filters(where_clause, relation_filters, params)
            sql = f"""
                SELECT {_SELECT_FIELDS},
                       1 - (task_embedding <=> %s::real[]) as score
                FROM knowledge
                {where_clause}
                ORDER BY task_embedding <=> %s::real[]
                LIMIT %s
            """
            final_params = [query_embedding] + params + [query_embedding, limit]
            cursor.execute(sql, tuple(final_params))
            results = cursor.fetchall()
            return [self._format_result(r) for r in results]
        finally:
            cursor.close()

    def query(self, filters: str, limit: int = 100, relation_filters: Optional[Dict[str, str]] = None) -> List[Dict]:
        """纯标量查询"""
        cursor = self._get_cursor()
        try:
            where_clause = self._build_where_clause(filters) if filters else ""
            params = []
            where_clause = self._apply_relation_filters(where_clause, relation_filters, params)
            sql = f"""
                SELECT {_SELECT_FIELDS}
                FROM knowledge
                {where_clause}
                LIMIT %s
            """
            final_params = params + [limit]
            cursor.execute(sql, tuple(final_params))
            results = cursor.fetchall()
            return [self._format_result(r) for r in results]
        finally:
            cursor.close()

    def get_by_id(self, knowledge_id: str, include_embedding: bool = False) -> Optional[Dict]:
        """根据ID获取知识（默认不返回embedding以提升性能）"""
        cursor = self._get_cursor()
        try:
            fields = _SELECT_FIELDS_WITH_EMB if include_embedding else _SELECT_FIELDS
            cursor.execute(f"""
                SELECT {fields}
                FROM knowledge WHERE id = %s
            """, (knowledge_id,))
            result = cursor.fetchone()
            return self._format_result(result) if result else None
        finally:
            cursor.close()

    def update(self, knowledge_id: str, updates: Dict):
        """更新知识"""
        cursor = self._get_cursor()
        try:
            # 分离关联字段和实体字段
            rel_keys = ('requirement_ids', 'requirement_links',
                        'capability_ids', 'capability_links',
                        'tool_ids', 'tool_links', 'resource_ids')
            rel_data = {k: updates.pop(k) for k in rel_keys if k in updates}

            if updates:
                set_parts = []
                params = []
                for key, value in updates.items():
                    if key in ('tags', 'source', 'eval'):
                        set_parts.append(f"{key} = %s")
                        params.append(json.dumps(value))
                    else:
                        set_parts.append(f"{key} = %s")
                        params.append(value)
                params.append(knowledge_id)
                sql = f"UPDATE knowledge SET {', '.join(set_parts)} WHERE id = %s"
                cursor.execute(sql, params)

            # 更新关联表（全量替换）
            req_links = _normalize_links(rel_data, 'requirement_links', 'requirement_ids', 'related')
            if req_links is not None:
                cursor.execute("DELETE FROM requirement_knowledge WHERE knowledge_id = %s", (knowledge_id,))
                for req_id, rtype in req_links:
                    cursor.execute(
                        "INSERT INTO requirement_knowledge (requirement_id, knowledge_id, relation_type) "
                        "VALUES (%s, %s, %s) ON CONFLICT DO NOTHING",
                        (req_id, knowledge_id, rtype))

            cap_links = _normalize_links(rel_data, 'capability_links', 'capability_ids', 'related')
            if cap_links is not None:
                cursor.execute("DELETE FROM capability_knowledge WHERE knowledge_id = %s", (knowledge_id,))
                for cap_id, rtype in cap_links:
                    cursor.execute(
                        "INSERT INTO capability_knowledge (capability_id, knowledge_id, relation_type) "
                        "VALUES (%s, %s, %s) ON CONFLICT DO NOTHING",
                        (cap_id, knowledge_id, rtype))

            tool_links = _normalize_links(rel_data, 'tool_links', 'tool_ids', 'related')
            if tool_links is not None:
                cursor.execute("DELETE FROM tool_knowledge WHERE knowledge_id = %s", (knowledge_id,))
                for tool_id, rtype in tool_links:
                    cursor.execute(
                        "INSERT INTO tool_knowledge (tool_id, knowledge_id, relation_type) "
                        "VALUES (%s, %s, %s) ON CONFLICT DO NOTHING",
                        (tool_id, knowledge_id, rtype))

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

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

    def delete(self, knowledge_id: str):
        """删除知识及其关联表记录"""
        cursor = self._get_cursor()
        try:
            cascade_delete(cursor, 'knowledge', knowledge_id)
            self.conn.commit()
        finally:
            cursor.close()

    def add_relation(self, source_id: str, target_id: str, relation_type: str):
        """添加一条知识间关系（不删除已有关系）"""
        cursor = self._get_cursor()
        try:
            cursor.execute(
                "INSERT INTO knowledge_relation (source_id, target_id, relation_type) VALUES (%s, %s, %s) ON CONFLICT DO NOTHING",
                (source_id, target_id, relation_type))
            self.conn.commit()
        finally:
            cursor.close()

    def add_resource(self, knowledge_id: str, resource_id: str):
        """添加一条知识-资源关联（不删除已有关联）"""
        cursor = self._get_cursor()
        try:
            cursor.execute(
                "INSERT INTO knowledge_resource (knowledge_id, resource_id) VALUES (%s, %s) ON CONFLICT DO NOTHING",
                (knowledge_id, resource_id))
            self.conn.commit()
        finally:
            cursor.close()

    def add_requirement(self, knowledge_id: str, requirement_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",
                (requirement_id, knowledge_id, relation_type))
            self.conn.commit()
        finally:
            cursor.close()

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

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

    def count(self) -> int:
        """返回知识总数"""
        cursor = self._get_cursor()
        try:
            cursor.execute("SELECT COUNT(*) as count FROM knowledge")
            return cursor.fetchone()['count']
        finally:
            cursor.close()

    def _build_where_clause(self, filters: str) -> str:
        """将Milvus风格的过滤表达式转换为PostgreSQL WHERE子句"""
        if not filters:
            return ""

        where = filters

        import re

        # 替换操作符
        where = where.replace(' == ', ' = ')
        where = where.replace(' or ', ' OR ')
        where = where.replace(' and ', ' AND ')

        # 处理数组包含操作
        where = re.sub(r'array_contains\((\w+),\s*"([^"]+)"\)', r"\1 @> ARRAY['\2']", where)

        # 处理 eval["score"] 语法
        where = where.replace('eval["score"]', "(eval->>'score')::int")

        # 把所有剩余的双引号字符串值替换为单引号（PostgreSQL标准）
        where = re.sub(r'"([^"]*)"', r"'\1'", where)

        return f"WHERE {where}"

    def _format_result(self, row: Dict) -> Dict:
        """格式化查询结果"""
        if not row:
            return None
        result = dict(row)
        if 'tags' in result and isinstance(result['tags'], str):
            result['tags'] = json.loads(result['tags'])
        if 'source' in result and isinstance(result['source'], str):
            result['source'] = json.loads(result['source'])
        if 'eval' in result and isinstance(result['eval'], str):
            result['eval'] = json.loads(result['eval'])
        # 关联字段（来自 junction table 子查询，可能是 JSON 字符串或已解析的列表）
        for field in ('requirement_ids', 'capability_ids', 'tool_ids', 'resource_ids',
                      'requirement_links', 'capability_links', 'tool_links'):
            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] = []
        if 'relations' in result and isinstance(result['relations'], str):
            result['relations'] = json.loads(result['relations'])
        elif 'relations' in result and result['relations'] is None:
            result['relations'] = []
        if 'created_at' in result and result['created_at']:
            result['created_at'] = result['created_at'] * 1000
        if 'updated_at' in result and result['updated_at']:
            result['updated_at'] = result['updated_at'] * 1000
        return result

    def close(self):
        """关闭连接"""
        if self.conn:
            self.conn.close()

    def insert_batch(self, knowledge_list: List[Dict]):
        """批量插入知识"""
        if not knowledge_list:
            return

        cursor = self._get_cursor()
        try:
            data = []
            for k in knowledge_list:
                data.append((
                    k['id'], k.get('task_embedding') or k.get('embedding'),
                    k.get('content_embedding'),
                    k['message_id'], k['task'],
                    k['content'], k.get('types', []),
                    json.dumps(k.get('tags', {})), k.get('tag_keys', []),
                    k.get('scopes', []), k['owner'],
                    json.dumps(k.get('source', {})), json.dumps(k.get('eval', {})),
                    k['created_at'], k['updated_at'], k.get('status', 'approved'),
                ))

            execute_batch(cursor, """
                INSERT INTO knowledge (
                    id, task_embedding, content_embedding, message_id, task, content, types, tags,
                    tag_keys, scopes, owner, source, eval,
                    created_at, updated_at, status
                ) VALUES (%s, %s, %s, %s, %s, %s, %s, %s, %s, %s, %s, %s, %s, %s, %s, %s)
            """, data)

            # 批量写入关联表
            for k in knowledge_list:
                kid = k['id']
                req_links = _normalize_links(k, 'requirement_links', 'requirement_ids', 'related') or []
                for req_id, rtype in req_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))
                cap_links = _normalize_links(k, 'capability_links', 'capability_ids', 'related') or []
                for cap_id, rtype in cap_links:
                    cursor.execute(
                        "INSERT INTO capability_knowledge (capability_id, knowledge_id, relation_type) "
                        "VALUES (%s, %s, %s) ON CONFLICT DO NOTHING",
                        (cap_id, kid, rtype))
                tool_links = _normalize_links(k, 'tool_links', 'tool_ids', 'related') or []
                for tool_id, rtype in tool_links:
                    cursor.execute(
                        "INSERT INTO tool_knowledge (tool_id, knowledge_id, relation_type) "
                        "VALUES (%s, %s, %s) ON CONFLICT DO NOTHING",
                        (tool_id, kid, rtype))
                for res_id in k.get('resource_ids', []):
                    cursor.execute(
                        "INSERT INTO knowledge_resource (knowledge_id, resource_id) VALUES (%s, %s) ON CONFLICT DO NOTHING",
                        (kid, res_id))

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