package server

import (
	"net/http"
	"os"
	"path/filepath"
	"time"

	"github.com/danielgtaylor/huma/v2"
)

// fileResponses documents an endpoint that returns a file with Range support.
func fileResponses(description string, contentTypes ...string) map[string]*huma.Response {
	content := map[string]*huma.MediaType{}
	for _, contentType := range contentTypes {
		content[contentType] = &huma.MediaType{Schema: &huma.Schema{Type: "string", Format: "binary"}}
	}
	return map[string]*huma.Response{
		"200": {Description: description, Content: content},
		"206": {Description: "Part of the file, for a Range request", Content: content},
	}
}

// streamFile opens path and returns a response that sends it with Range support.
// contentType may be empty to detect it from the file extension. Audio has no write
// deadline because songs can take long to send to slow clients.
func streamFile(path, contentType string, audio bool) (*huma.StreamResponse, error) {
	f, err := os.Open(path)
	if err != nil {
		return nil, huma.Error404NotFound("Not Found")
	}
	return streamOpenFile(f, contentType, audio)
}

func streamOpenFile(f *os.File, contentType string, audio bool) (*huma.StreamResponse, error) {
	info, err := f.Stat()
	if err != nil || info.IsDir() {
		f.Close()
		return nil, huma.Error404NotFound("Not Found")
	}
	return &huma.StreamResponse{Body: func(ctx huma.Context) {
		defer f.Close()
		c := echoContext(ctx)
		if contentType != "" {
			c.Response().Header().Set("Content-Type", contentType)
		}
		if audio {
			_ = http.NewResponseController(c.Response()).SetWriteDeadline(time.Time{})
		}
		http.ServeContent(c.Response(), c.Request(), filepath.Base(f.Name()), info.ModTime(), f)
	}}, nil
}

// streamSong streams the song at path, or returns err mapped to an API error.
// The same URL returns a different song each time (random songs, next, previous),
// so browsers must not cache it. Without this they cache the response because of
// its Last-Modified header, and play the same song again.
func streamSong(path string, err error) (*huma.StreamResponse, error) {
	if err != nil {
		return nil, apiError(err)
	}
	resp, err := streamFile(path, "audio/mpeg", true)
	if err != nil {
		return nil, err
	}
	body := resp.Body
	resp.Body = func(ctx huma.Context) {
		ctx.SetHeader("Cache-Control", "no-store")
		body(ctx)
	}
	return resp, nil
}