package audio

import (
	"bytes"
	"io"
	"log"
	"net/http"
	"net/url"
	"os"
	"strings"
)

type reader struct {
	bytes.Reader
	io.Closer
}

func (a *reader) Seek(offset int64, whence int) (int64, error) {
	return a.Reader.Seek(offset, whence)
}

func toSeeker(src io.ReadCloser) io.ReadCloser {
	buf := &bytes.Buffer{}
	_, _ = io.Copy(buf, src)
	return &reader{
		Reader: *bytes.NewReader(buf.Bytes()),
		Closer: src,
	}
}

func open(u string) io.ReadCloser {
	p, _ := strings.CutPrefix(u, "file://")
	f, e := os.Open(p)
	if e != nil {
		log.Printf("音频文件 [%v] 打开错误: %v\n", u, e)
		return nil
	}
	return f
}

func get(u string) io.ReadCloser {
	resp, e := http.Get(u)
	if e != nil {
		log.Printf("音频文件 [%v] 下载失败: %v\n", u, e)
		return nil
	}
	return resp.Body
}

func LinkAudio(link string) (bgm io.ReadCloser) {
	u, err := url.Parse(link)
	if err != nil {
		log.Println("音频 URL 解析错误: ", err)
	} else {
		if u.Scheme == "file" {
			bgm = open(u.String())
		} else if u.Scheme == "http" || u.Scheme == "https" {
			bgm = get(u.String())
		} else {
			log.Printf("不支持的音频文件协议: %v\n", u.String())
			return
		}
		bgm = toSeeker(bgm)
	}
	return
}