package utils

import (
	"fmt"
	"io"
	"net/http"
	"os"
	"strings"
	"time"
)

func DownloadFile(url string, path string) (bool, string) {
	// 创建HTTP客户端
	client := &http.Client{
		Timeout: 5 * time.Second,
	}

	return DownloadFileWithClient(client, url, path)
}

func DownloadFileWithClient(client *http.Client, url string, path string) (bool, string) {
	return downloadWithProgress(client, url, path)
}

// 带进度显示的下载函数
func downloadWithProgress(client *http.Client, url, dest string) (bool, string) {
	// 创建目标文件
	file, err := os.Create(dest)
	if err != nil {
		return false, fmt.Sprintf("创建文件失败: %w", err)
	}
	defer file.Close()

	// 发起请求
	resp, err := client.Get(url)
	if err != nil {
		return false, fmt.Sprintf("HTTP请求失败: %w", err)
	}
	defer resp.Body.Close()

	if resp.StatusCode != http.StatusOK {
		return false, fmt.Sprintf("服务器返回错误状态码: %s", resp.Status)
	}

	// 获取文件大小
	size := resp.ContentLength
	var downloaded int64

	// 打印下载信息
	fmt.Printf("开始下载文件: %s 文件大小: %s\n", url, HumanSizeInt(size))

	// 创建带进度跟踪的Reader
	progressReader := &progressReader{
		Reader: resp.Body,
		Reporter: func(r int64) {
			downloaded += r
			printProgress(downloaded, size)
		},
	}

	// 执行拷贝
	if _, err := io.Copy(file, progressReader); err != nil {
		return false, fmt.Sprintf("文件拷贝失败: %w", err)
	}

	fmt.Print("\n") // 保持最后进度显示的完整性
	return true, fmt.Sprintf("文件下载成功: %s", dest)
}

// 进度跟踪Reader
type progressReader struct {
	io.Reader
	Reporter func(r int64)
}

func (pr *progressReader) Read(p []byte) (int, error) {
	n, err := pr.Reader.Read(p)
	if n > 0 {
		pr.Reporter(int64(n))
	}
	return n, err
}

// 打印进度信息
func printProgress(downloaded, total int64) {
	const barLength = 40
	percent := float64(downloaded) / float64(total) * 100

	// 生成进度条
	filled := int(barLength * downloaded / total)
	bar := fmt.Sprintf("[%s%s]",
		strings.Repeat("=", filled),
		strings.Repeat(" ", barLength-filled))

	// 格式化为人类可读大小
	humanSize := func(bytes int64) string {
		const unit = 1024
		if bytes < unit {
			return fmt.Sprintf("%d B", bytes)
		}
		div, exp := int64(unit), 0
		for n := bytes / unit; n >= unit; n /= unit {
			div *= unit
			exp++
		}
		return fmt.Sprintf("%.1f %ciB", float64(bytes)/float64(div), "KMGTPE"[exp])
	}

	fmt.Printf("\r%-45s %6.2f%%  %s/%s", bar, percent,
		humanSize(downloaded), humanSize(total))
}