// Copyright 2025 linux.do
// Copyright 2026 Arctel.net
// SPDX-License-Identifier: Apache-2.0

// Package db 提供数据库连接与基础设施
package db

import (
	"context"
	"log"
	"time"

	"github.com/ClickHouse/clickhouse-go/v2"
	"github.com/ClickHouse/clickhouse-go/v2/lib/driver"
	"github.com/Rain-kl/Wavelet/internal/config"
)

const (
	clickhouseMaxExecTime       = 60 // ClickHouse 最大执行时间（秒）
	clickhouseReadTimeoutFactor = 2  // ReadTimeout 为 DialTimeout 的倍数
)

var (
	// ChConn ClickHouse 连接实例
	ChConn driver.Conn
)

func init() {
	if !config.Config.ClickHouse.Enabled {
		return
	}

	cfg := config.Config.ClickHouse
	var err error

	// 配置 ClickHouse 连接
	ChConn, err = clickhouse.Open(&clickhouse.Options{
		Addr: cfg.Hosts,
		Auth: clickhouse.Auth{
			Database: cfg.Database,
			Username: cfg.Username,
			Password: cfg.Password,
		},
		Settings: clickhouse.Settings{
			"max_execution_time": clickhouseMaxExecTime,
		},
		Compression: &clickhouse.Compression{
			Method: clickhouse.CompressionLZ4,
		},
		DialTimeout:     time.Duration(cfg.DialTimeout) * time.Second,
		MaxOpenConns:    cfg.MaxOpenConn,
		MaxIdleConns:    cfg.MaxIdleConn,
		ConnMaxLifetime: time.Duration(cfg.ConnMaxLifetime) * time.Second,
		ReadTimeout:     time.Duration(cfg.DialTimeout*clickhouseReadTimeoutFactor) * time.Second,
		BlockBufferSize: cfg.BlockBufferSize,
	})

	if err != nil {
		log.Fatalf("[ClickHouse] init connection failed: %v\n", err)
	}

	// 测试连接
	if err = ChConn.Ping(context.Background()); err != nil {
		log.Fatalf("[ClickHouse] ping failed: %v\n", err)
	}

	log.Println("[ClickHouse] connection established successfully")
}