import {
  DatabaseConnector,
  ConnectionConfig,
  QueryResult,
} from "../interfaces/DatabaseConnector";
import { ConnectionTestResult, TableInfo } from "../types/externalDbTypes";
import * as mysql from "mysql2/promise";

export class MariaDBConnector implements DatabaseConnector {
  private connection: mysql.Connection | null = null;
  private config: ConnectionConfig;

  constructor(config: ConnectionConfig) {
    this.config = config;
  }

  async connect(): Promise<void> {
    if (!this.connection) {
      this.connection = await mysql.createConnection({
        host: this.config.host,
        port: this.config.port,
        user: this.config.user,
        password: this.config.password,
        database: this.config.database,
        // 🔧 MySQL2에서 지원하는 타임아웃 설정
        connectTimeout: this.config.connectionTimeoutMillis || 30000, // 연결 타임아웃 30초
        ssl: typeof this.config.ssl === "boolean" ? undefined : this.config.ssl,
        // 🔧 MySQL2에서 지원하는 추가 설정
        charset: "utf8mb4",
        timezone: "Z",
        supportBigNumbers: true,
        bigNumberStrings: true,
        // 🔧 연결 풀 설정 (단일 연결이지만 안정성을 위해)
        dateStrings: true,
        debug: false,
        trace: false,
      });
    }
  }

  async disconnect(): Promise<void> {
    if (this.connection) {
      await this.connection.end();
      this.connection = null;
    }
  }

  async testConnection(): Promise<ConnectionTestResult> {
    const startTime = Date.now();
    try {
      await this.connect();
      const [rows] = await this.connection!.query(
        "SELECT VERSION() as version"
      );
      const version = (rows as any[])[0]?.version || "Unknown";
      const responseTime = Date.now() - startTime;
      await this.disconnect();
      return {
        success: true,
        message: "MariaDB/MySQL 연결이 성공했습니다.",
        details: {
          response_time: responseTime,
          server_version: version,
        },
      };
    } catch (error: any) {
      await this.disconnect();
      return {
        success: false,
        message: "MariaDB/MySQL 연결에 실패했습니다.",
        error: {
          code: "CONNECTION_FAILED",
          details: error.message || "알 수 없는 오류",
        },
      };
    }
  }

  async executeQuery(query: string): Promise<QueryResult> {
    try {
      await this.connect();

      // 🔧 쿼리 타임아웃 수동 구현 (60초)
      const queryTimeout = this.config.queryTimeoutMillis || 60000;
      const queryPromise = this.connection!.query(query);
      const timeoutPromise = new Promise((_, reject) => {
        setTimeout(() => reject(new Error("쿼리 실행 타임아웃")), queryTimeout);
      });

      const [rows, fields] = (await Promise.race([
        queryPromise,
        timeoutPromise,
      ])) as any;
      await this.disconnect();
      return {
        rows: rows as any[],
        fields: fields as any[],
      };
    } catch (error: any) {
      await this.disconnect();
      throw new Error(`쿼리 실행 실패: ${error.message}`);
    }
  }

  async getTables(): Promise<TableInfo[]> {
    try {
      await this.connect();
      const [rows] = await this.connection!.query(`
        SELECT 
          TABLE_NAME as table_name,
          TABLE_COMMENT as description
        FROM information_schema.TABLES
        WHERE TABLE_SCHEMA = DATABASE()
        ORDER BY TABLE_NAME;
      `);

      const tables: TableInfo[] = [];
      for (const row of rows as any[]) {
        const columns = await this.getColumns(row.table_name);
        tables.push({
          table_name: row.table_name,
          description: row.description || null,
          columns: columns,
        });
      }
      await this.disconnect();
      return tables;
    } catch (error: any) {
      await this.disconnect();
      throw new Error(`테이블 목록 조회 실패: ${error.message}`);
    }
  }

  async getColumns(tableName: string): Promise<any[]> {
    try {
      console.log(`🔍 MariaDB 컬럼 조회 시작: ${tableName}`);
      await this.connect();

      // 🔧 컬럼 조회 타임아웃 수동 구현 (30초)
      const queryTimeout = this.config.queryTimeoutMillis || 30000;
      // 스키마명을 명시적으로 확인
      const schemaQuery = `SELECT DATABASE() as schema_name`;
      const [schemaResult] = await this.connection!.query(schemaQuery);
      const schemaName =
        (schemaResult as any[])[0]?.schema_name || this.config.database;

      console.log(`📋 사용할 스키마: ${schemaName}`);

      const query = `
        SELECT 
          COLUMN_NAME as column_name,
          DATA_TYPE as data_type,
          IS_NULLABLE as is_nullable,
          COLUMN_DEFAULT as column_default,
          COLUMN_COMMENT as column_comment
        FROM information_schema.COLUMNS
        WHERE TABLE_SCHEMA = ? AND TABLE_NAME = ?
        ORDER BY ORDINAL_POSITION;
      `;

      console.log(
        `📋 실행할 쿼리: ${query.trim()}, 파라미터: [${schemaName}, ${tableName}]`
      );

      const queryPromise = this.connection!.query(query, [
        schemaName,
        tableName,
      ]);
      const timeoutPromise = new Promise((_, reject) => {
        setTimeout(() => reject(new Error("컬럼 조회 타임아웃")), queryTimeout);
      });

      const [rows] = (await Promise.race([
        queryPromise,
        timeoutPromise,
      ])) as any;

      console.log(
        `✅ MariaDB 컬럼 조회 완료: ${tableName}, ${rows ? rows.length : 0}개 컬럼`
      );
      await this.disconnect();
      return rows as any[];
    } catch (error: any) {
      await this.disconnect();
      throw new Error(`컬럼 정보 조회 실패: ${error.message}`);
    }
  }
}