import os
import json
from datetime import datetime
from typing import List, Dict, Any

try:
    import pymysql
except Exception as exc:
    pymysql = None
    _MYSQL_IMPORT_ERROR = str(exc)


def get_mysql_config() -> Dict[str, Any]:
    return {
        "host": os.getenv("MYSQL_HOST", "127.0.0.1"),
        "port": int(os.getenv("MYSQL_PORT", "3306")),
        "user": os.getenv("MYSQL_USER", "root"),
        "password": os.getenv("MYSQL_PASSWORD", "123456"),
        "database": os.getenv("MYSQL_DATABASE", "arbitration_system"),
        "charset": "utf8mb4"
    }


def get_mysql_connection(use_database: bool = True):
    if pymysql is None:
        raise RuntimeError(f"MySQL驱动不可用: {_MYSQL_IMPORT_ERROR}")
    cfg = get_mysql_config()
    if not use_database:
        cfg = {k: v for k, v in cfg.items() if k != "database"}
    return pymysql.connect(**cfg)


def index_exists(cursor, database: str, table: str, index_name: str) -> bool:
    cursor.execute(
        """
        SELECT 1
        FROM information_schema.statistics
        WHERE table_schema=%s AND table_name=%s AND index_name=%s
        LIMIT 1
        """,
        (database, table, index_name)
    )
    return cursor.fetchone() is not None


def init_case_db() -> None:
    cfg = get_mysql_config()
    conn = get_mysql_connection(use_database=False)
    try:
        cursor = conn.cursor()
        cursor.execute(f"CREATE DATABASE IF NOT EXISTS `{cfg['database']}` CHARACTER SET utf8mb4")
        conn.commit()
    finally:
        conn.close()

    conn = get_mysql_connection(use_database=True)
    try:
        cursor = conn.cursor()
        cursor.execute(
            """
            CREATE TABLE IF NOT EXISTS cases (
                id BIGINT PRIMARY KEY AUTO_INCREMENT,
                case_id VARCHAR(255),
                summary_text TEXT,
                case_profile_json LONGTEXT,
                dispute_points_json LONGTEXT,
                law_results_json LONGTEXT,
                evidence_results_json LONGTEXT,
                final_judgement_json LONGTEXT,
                embedding_json LONGTEXT,
                created_at DATETIME
            ) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4
            """
        )
        if not index_exists(cursor, cfg["database"], "cases", "idx_cases_case_id"):
            cursor.execute("CREATE INDEX idx_cases_case_id ON cases(case_id)")
        cursor.execute(
            """
            CREATE TABLE IF NOT EXISTS case_management (
                id BIGINT PRIMARY KEY AUTO_INCREMENT,
                case_id VARCHAR(255) UNIQUE,
                title VARCHAR(255),
                description TEXT,
                status VARCHAR(50),
                stage VARCHAR(50),
                updated_at DATETIME
            ) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4
            """
        )
        if not index_exists(cursor, cfg["database"], "case_management", "idx_case_management_case_id"):
            cursor.execute("CREATE INDEX idx_case_management_case_id ON case_management(case_id)")
        conn.commit()
    finally:
        conn.close()


def store_case_record(
    case_id: str,
    summary_text: str,
    case_profile: Dict[str, Any],
    dispute_points: List[str],
    law_results: Dict[str, Any],
    evidence_results: Dict[str, Any],
    final_judgement: Dict[str, Any],
    embedding: List[float]
) -> None:
    conn = get_mysql_connection(use_database=True)
    try:
        cursor = conn.cursor()
        cursor.execute(
            """
            INSERT INTO cases (
                case_id, summary_text, case_profile_json, dispute_points_json,
                law_results_json, evidence_results_json, final_judgement_json,
                embedding_json, created_at
            ) VALUES (%s, %s, %s, %s, %s, %s, %s, %s, %s)
            """,
            (
                case_id,
                summary_text,
                json.dumps(case_profile, ensure_ascii=False),
                json.dumps(dispute_points, ensure_ascii=False),
                json.dumps(law_results, ensure_ascii=False),
                json.dumps(evidence_results, ensure_ascii=False),
                json.dumps(final_judgement, ensure_ascii=False),
                json.dumps(embedding, ensure_ascii=False),
                datetime.utcnow()
            )
        )
        conn.commit()
    finally:
        conn.close()


def fetch_similar_cases(embedding: List[float], top_k: int = 3) -> List[Dict[str, Any]]:
    conn = get_mysql_connection(use_database=True)
    try:
        cursor = conn.cursor()
        cursor.execute(
            """
            SELECT case_id, summary_text, final_judgement_json, embedding_json
            FROM cases
            WHERE embedding_json IS NOT NULL AND embedding_json != ''
            """
        )
        rows = cursor.fetchall()
    finally:
        conn.close()

    scored = []
    for case_id, summary_text, final_judgement_json, embedding_json in rows:
        try:
            vec = json.loads(embedding_json)
        except Exception:
            vec = []
        scored.append(
            {
                "case_id": case_id,
                "summary_text": summary_text,
                "final_judgement_json": final_judgement_json,
                "embedding": vec
            }
        )
    return scored


def parse_case_description(description: str) -> Dict[str, Any]:
    if not description or not isinstance(description, str):
        return {}
    try:
        data = json.loads(description)
        return data if isinstance(data, dict) else {}
    except Exception:
        return {}


def normalize_case_description(case_id: str, description: str) -> str:
    if not case_id:
        return description
    existing = fetch_case_management(case_id)
    existing_desc = existing.get("description", "") if existing else ""
    existing_data = parse_case_description(existing_desc)
    new_data = parse_case_description(description)
    if existing_data.get("materials") and not new_data.get("materials"):
        desc_text = description or existing_data.get("description", "")
        merged = {"description": desc_text, "materials": existing_data.get("materials", {})}
        return json.dumps(merged, ensure_ascii=False)
    return description


def upsert_case_management(case_id: str, title: str, description: str, status: str, stage: str) -> Dict[str, Any]:
    conn = get_mysql_connection(use_database=True)
    try:
        cursor = conn.cursor()
        description = normalize_case_description(case_id, description)
        cursor.execute(
            """
            INSERT INTO case_management (case_id, title, description, status, stage, updated_at)
            VALUES (%s, %s, %s, %s, %s, %s)
            ON DUPLICATE KEY UPDATE
                title=VALUES(title),
                description=VALUES(description),
                status=VALUES(status),
                stage=VALUES(stage),
                updated_at=VALUES(updated_at)
            """,
            (case_id, title, description, status, stage, datetime.utcnow())
        )
        conn.commit()
    finally:
        conn.close()
    return {"case_id": case_id, "title": title, "description": description, "status": status, "stage": stage}


def update_case_materials(case_id: str, materials: Dict[str, Any]) -> None:
    if not case_id:
        return
    existing = fetch_case_management(case_id)
    existing_desc = existing.get("description", "") if existing else ""
    existing_data = parse_case_description(existing_desc)
    description_text = existing_desc if not existing_data else existing_data.get("description", "")
    payload = {
        "description": description_text,
        "materials": materials or {}
    }
    conn = get_mysql_connection(use_database=True)
    try:
        cursor = conn.cursor()
        cursor.execute(
            """
            UPDATE case_management
            SET description=%s, updated_at=%s
            WHERE case_id=%s
            """,
            (json.dumps(payload, ensure_ascii=False), datetime.utcnow(), case_id)
        )
        conn.commit()
    finally:
        conn.close()


def list_case_management() -> List[Dict[str, Any]]:
    conn = get_mysql_connection(use_database=True)
    try:
        cursor = conn.cursor()
        cursor.execute(
            """
            SELECT case_id, title, description, status, stage, updated_at
            FROM case_management
            ORDER BY updated_at DESC
            """
        )
        rows = cursor.fetchall()
    finally:
        conn.close()
    results = []
    for case_id, title, description, status, stage, updated_at in rows:
        results.append(
            {
                "case_id": case_id,
                "title": title,
                "description": description,
                "status": status,
                "stage": stage,
                "updated_at": updated_at.isoformat() if updated_at else ""
            }
        )
    return results


def fetch_case_management(case_id: str) -> Dict[str, Any]:
    if not case_id:
        return {}
    conn = get_mysql_connection(use_database=True)
    try:
        cursor = conn.cursor()
        cursor.execute(
            """
            SELECT case_id, title, description, status, stage, updated_at
            FROM case_management
            WHERE case_id=%s
            LIMIT 1
            """,
            (case_id,)
        )
        row = cursor.fetchone()
    finally:
        conn.close()
    if not row:
        return {}
    case_id, title, description, status, stage, updated_at = row
    return {
        "case_id": case_id,
        "title": title,
        "description": description or "",
        "status": status,
        "stage": stage,
        "updated_at": updated_at.isoformat() if updated_at else ""
    }


def fetch_case_record(case_id: str) -> Dict[str, Any]:
    if not case_id:
        return {}
    conn = get_mysql_connection(use_database=True)
    try:
        cursor = conn.cursor()
        cursor.execute(
            """
            SELECT summary_text, case_profile_json, dispute_points_json, law_results_json,
                   evidence_results_json, final_judgement_json, embedding_json, created_at
            FROM cases
            WHERE case_id=%s
            ORDER BY created_at DESC
            LIMIT 1
            """,
            (case_id,)
        )
        row = cursor.fetchone()
    finally:
        conn.close()
    if not row:
        return {}
    (
        summary_text,
        case_profile_json,
        dispute_points_json,
        law_results_json,
        evidence_results_json,
        final_judgement_json,
        embedding_json,
        created_at
    ) = row

    def parse_json(value: str, fallback):
        if not value:
            return fallback
        try:
            parsed = json.loads(value)
            return parsed if parsed is not None else fallback
        except Exception:
            return fallback

    return {
        "summary_text": summary_text or "",
        "case_profile": parse_json(case_profile_json, {}),
        "dispute_points": parse_json(dispute_points_json, []),
        "law_results": parse_json(law_results_json, {}),
        "evidence_results": parse_json(evidence_results_json, {}),
        "final_judgement": parse_json(final_judgement_json, {}),
        "embedding": parse_json(embedding_json, []),
        "created_at": created_at.isoformat() if created_at else ""
    }


def delete_case_management(case_id: str) -> None:
    conn = get_mysql_connection(use_database=True)
    try:
        cursor = conn.cursor()
        cursor.execute("DELETE FROM case_management WHERE case_id=%s", (case_id,))
        conn.commit()
    finally:
        conn.close()