minstrel/internal/release/files.go

package release

import (
	"path"
	"strconv"
	"strings"
)

// File is one file inside a torrent.
type File struct {
	Index int
	Path  string
	Size  int64
}

// Contents is what a torrent's file list holds.
type Contents struct {
	Audio int
	Video int
	// Format is the format most of the audio files are in, "" when none.
	Format string
}

var videoExt = map[string]bool{
	"mkv": true, "mp4": true, "avi": true, "m2ts": true, "vob": true,
	"mov": true, "webm": true, "wmv": true, "m4v": true, "ts": true,
}

// Inspect counts a file list's audio and video files.
func Inspect(files []File) Contents {
	var c Contents
	formats := map[string]int{}
	for _, f := range files {
		ext := strings.TrimPrefix(strings.ToLower(path.Ext(f.Path)), ".")
		if fm := formatOf(ext); fm != "" {
			c.Audio++
			formats[fm]++
		} else if videoExt[ext] {
			c.Video++
		}
	}
	best := 0
	for fm, n := range formats {
		if n > best || (n == best && formatRank[fm] > formatRank[c.Format]) {
			c.Format, best = fm, n
		}
	}
	return c
}

// JudgeFiles says what a torrent's files say about whether it is the album:
// a veto (code and sentence), or a doubt for a person, or nothing.
func JudgeFiles(w Want, files []File) (veto, reason, doubt string) {
	if len(files) == 0 {
		return "", "", ""
	}
	c := Inspect(files)
	switch {
	case c.Audio == 0 && c.Video > 0:
		return VetoVideo, "It holds video files and no audio.", ""
	case c.Audio == 0:
		return VetoNoAudio, "It holds no audio files Minstrel can read.", ""
	case w.MinTracks > 0 && c.Audio < w.MinTracks:
		return VetoIncomplete, "It holds " + tracks(c.Audio) + "; the shortest edition has " + tracks(w.MinTracks) + ".", ""
	case w.MaxTracks > 0 && c.Audio > 2*w.MaxTracks+4:
		return "", "", "It holds " + tracks(c.Audio) + ", more than any edition of the album has: probably more than one album."
	}
	return "", "", ""
}

func tracks(n int) string {
	if n == 1 {
		return "1 track"
	}
	return strconv.Itoa(n) + " tracks"
}