package urlparse

import (
	"net/url"
	"regexp"
	"strings"
)

type URLKind string

const (
	KindGeneric       URLKind = "generic"
	KindDeezerDynamic URLKind = "deezer_dynamic"
	KindSoundcloud    URLKind = "soundcloud"
)

type ParsedURL struct {
	OriginalURL string
	Source      string
	MediaType   string
	ID          string
	Kind        URLKind
}

var deezerDynamicRe = regexp.MustCompile(`^https?://dzr\.page\.link/`)

func Parse(raw string) *ParsedURL {
	if deezerDynamicRe.MatchString(raw) {
		return &ParsedURL{
			OriginalURL: raw,
			Source:      "deezer",
			Kind:        KindDeezerDynamic,
		}
	}

	u, err := url.Parse(raw)
	if err != nil || u.Host == "" {
		return nil
	}

	host := normalizeHost(u.Host)
	path := strings.Trim(u.EscapedPath(), "/")
	parts := splitParts(path)

	switch {
	case isQobuzHost(host):
		return parseQobuz(raw, parts)
	case isTidalHost(host):
		return parseTidal(raw, parts)
	case isDeezerHost(host):
		return parseDeezer(raw, parts)
	case host == "soundcloud.com":
		return parseSoundcloud(raw, parts)
	default:
		return nil
	}
}

func parseQobuz(raw string, parts []string) *ParsedURL {
	if len(parts) < 2 {
		return nil
	}

	if isLocaleToken(parts[0]) {
		parts = parts[1:]
	}
	if len(parts) < 2 {
		return nil
	}

	mediaType := parts[0]
	if !isSupportedMedia(mediaType) {
		return nil
	}
	id := parts[len(parts)-1]
	if id == "" {
		return nil
	}

	return &ParsedURL{OriginalURL: raw, Source: "qobuz", MediaType: mediaType, ID: id, Kind: KindGeneric}
}

func parseTidal(raw string, parts []string) *ParsedURL {
	if len(parts) < 2 {
		return nil
	}

	if parts[0] == "browse" {
		parts = parts[1:]
	}
	if len(parts) < 2 {
		return nil
	}

	mediaType := parts[0]
	if !isSupportedMedia(mediaType) {
		return nil
	}
	id := parts[1]
	if id == "" {
		return nil
	}

	return &ParsedURL{OriginalURL: raw, Source: "tidal", MediaType: mediaType, ID: id, Kind: KindGeneric}
}

func parseDeezer(raw string, parts []string) *ParsedURL {
	if len(parts) < 2 {
		return nil
	}

	if isLangToken(parts[0]) {
		parts = parts[1:]
	}
	if len(parts) < 2 {
		return nil
	}

	mediaType := parts[0]
	if !isSupportedMedia(mediaType) {
		return nil
	}
	id := parts[1]
	if id == "" {
		return nil
	}

	return &ParsedURL{OriginalURL: raw, Source: "deezer", MediaType: mediaType, ID: id, Kind: KindGeneric}
}

func parseSoundcloud(raw string, parts []string) *ParsedURL {
	if len(parts) < 2 {
		return nil
	}

	mediaType := "track"
	if len(parts) >= 3 && parts[1] == "sets" {
		mediaType = "playlist"
	}

	return &ParsedURL{OriginalURL: raw, Source: "soundcloud", MediaType: mediaType, ID: raw, Kind: KindSoundcloud}
}

func splitParts(path string) []string {
	if path == "" {
		return nil
	}
	raw := strings.Split(path, "/")
	parts := make([]string, 0, len(raw))
	for _, p := range raw {
		if p != "" {
			parts = append(parts, p)
		}
	}
	return parts
}

func normalizeHost(host string) string {
	h := strings.ToLower(host)
	return strings.TrimPrefix(h, "www.")
}

func isQobuzHost(host string) bool {
	return host == "qobuz.com" || host == "open.qobuz.com" || host == "play.qobuz.com"
}

func isTidalHost(host string) bool {
	return host == "tidal.com" || host == "open.tidal.com" || host == "listen.tidal.com"
}

func isDeezerHost(host string) bool {
	return host == "deezer.com"
}

func isSupportedMedia(mediaType string) bool {
	switch mediaType {
	case "album", "track", "playlist", "artist", "label":
		return true
	default:
		return false
	}
}

func isLocaleToken(s string) bool {
	if len(s) != 5 {
		return false
	}
	return s[2] == '-' && isAlpha(s[:2]) && isAlpha(s[3:])
}

func isLangToken(s string) bool {
	return len(s) == 2 && isAlpha(s)
}

func isAlpha(s string) bool {
	for _, r := range s {
		if (r < 'a' || r > 'z') && (r < 'A' || r > 'Z') {
			return false
		}
	}
	return true
}