package soundcloud

import (
	"context"
	"encoding/json"
	"errors"
	"fmt"
	"io"
	"net/http"
	"net/url"
	"os/exec"
	"regexp"
	"strings"
	"sync"
	"time"

	"streamrip-go/internal/config"
	"streamrip-go/internal/jsonutil"
	"streamrip-go/internal/provider"
)

var errUnsupportedMediaType = errors.New("unsupported soundcloud media type")

var soundcloudSearchBaseURL = "https://soundcloud.com"

type commandRunner func(ctx context.Context, name string, args ...string) ([]byte, error)

type Client struct {
	cfg      *config.Config
	loggedIn bool
	bin      string
	run      commandRunner
	http     *http.Client
	mu       sync.Mutex
	cache    map[string]map[string]any
}

func New(cfg *config.Config) *Client {
	return &Client{
		cfg:   cfg,
		bin:   "yt-dlp",
		run:   runCommand,
		http:  &http.Client{Timeout: 20 * time.Second},
		cache: map[string]map[string]any{},
	}
}

func (c *Client) Source() string {
	return "soundcloud"
}

func (c *Client) LoggedIn() bool {
	return c.loggedIn
}

func (c *Client) Login(context.Context) error {
	if _, err := exec.LookPath(c.bin); err != nil {
		return fmt.Errorf("yt-dlp is required for soundcloud downloads/search. install it and ensure it is in $PATH (e.g. pipx install yt-dlp): %w", err)
	}
	c.loggedIn = true
	return nil
}

func (c *Client) Search(ctx context.Context, mediaType, query string, limit int) ([]map[string]any, error) {
	if !c.loggedIn {
		return nil, errors.New("soundcloud client not logged in")
	}
	if limit <= 0 {
		limit = 20
	}
	if mediaType == "track" {
		return c.searchTracks(ctx, query, limit)
	}
	if mediaType == "playlist" {
		return c.searchPlaylists(ctx, query, limit)
	}
	return nil, fmt.Errorf("%w: %s", errUnsupportedMediaType, mediaType)
}

func (c *Client) searchTracks(ctx context.Context, query string, limit int) ([]map[string]any, error) {

	target := fmt.Sprintf("scsearch%d:%s", limit, query)
	b, err := c.run(ctx, c.bin, "-J", "--flat-playlist", "--skip-download", "--no-warnings", target)
	if err != nil {
		return nil, err
	}
	root, err := parseJSONMap(b)
	if err != nil {
		return nil, err
	}
	entries := asAnySlice(root["entries"])
	if len(entries) == 0 {
		return []map[string]any{}, nil
	}
	items := make([]any, 0, len(entries))
	for _, e := range entries {
		m, ok := e.(map[string]any)
		if !ok {
			continue
		}
		id := canonicalSoundcloudURL(m)
		if id == "" {
			continue
		}
		artist := strings.TrimSpace(jsonutil.StringFromAny(m["uploader"]))
		if artist == "" {
			artist = strings.TrimSpace(jsonutil.StringFromAny(m["channel"]))
		}
		artistID := strings.TrimSpace(jsonutil.FirstNonEmpty(jsonutil.StringFromAny(m["uploader_id"]), jsonutil.StringFromAny(m["channel_id"])))
		item := map[string]any{
			"id":    id,
			"title": jsonutil.StringFromAny(m["title"]),
			"artist": map[string]any{
				"name": artist,
			},
		}
		if artistID != "" {
			item["artist"] = map[string]any{"name": artist, "id": artistID}
		}
		if trackID := strings.TrimSpace(jsonutil.StringFromAny(m["id"])); trackID != "" {
			item["source_track_id"] = trackID
		}
		items = append(items, item)
	}
	return []map[string]any{{"items": items}}, nil
}

func (c *Client) searchPlaylists(ctx context.Context, query string, limit int) ([]map[string]any, error) {
	searchURL := strings.TrimSuffix(soundcloudSearchBaseURL, "/") + "/search/sets?q=" + url.QueryEscape(query)
	req, err := http.NewRequestWithContext(ctx, http.MethodGet, searchURL, nil)
	if err != nil {
		return nil, err
	}
	req.Header.Set("User-Agent", "Mozilla/5.0")

	resp, err := c.http.Do(req)
	if err != nil {
		return nil, err
	}
	defer func() { _ = resp.Body.Close() }()
	if resp.StatusCode < 200 || resp.StatusCode >= 300 {
		return nil, fmt.Errorf("soundcloud playlist search failed: status=%d", resp.StatusCode)
	}
	body, err := io.ReadAll(resp.Body)
	if err != nil {
		return nil, err
	}

	re := regexp.MustCompile(`/(?:[A-Za-z0-9._-]+)/sets/(?:[A-Za-z0-9._%~-]+)`)
	paths := re.FindAllString(string(body), -1)
	if len(paths) == 0 {
		return []map[string]any{}, nil
	}
	seen := map[string]struct{}{}
	items := make([]any, 0, limit)
	for _, path := range paths {
		if _, ok := seen[path]; ok {
			continue
		}
		seen[path] = struct{}{}
		playlistURL := "https://soundcloud.com" + path
		info, infoErr := c.playlistInfo(ctx, playlistURL)
		if infoErr != nil {
			continue
		}
		title := strings.TrimSpace(jsonutil.StringFromAny(info["title"]))
		if title == "" {
			title = strings.Trim(strings.ReplaceAll(path, "/", " "), " ")
		}
		artist := strings.TrimSpace(jsonutil.FirstNonEmpty(jsonutil.StringFromAny(info["uploader"]), jsonutil.StringFromAny(info["channel"])))
		artistID := strings.TrimSpace(jsonutil.FirstNonEmpty(jsonutil.StringFromAny(info["uploader_id"]), jsonutil.StringFromAny(info["channel_id"])))
		trackCount := 0
		if entries := asAnySlice(info["entries"]); len(entries) > 0 {
			trackCount = len(entries)
		}
		canonical := jsonutil.FirstNonEmpty(canonicalSoundcloudURL(info), playlistURL)
		item := map[string]any{
			"id":           canonical,
			"title":        title,
			"tracks_count": trackCount,
			"artist":       map[string]any{"name": artist},
		}
		if artistID != "" {
			item["artist"] = map[string]any{"name": artist, "id": artistID}
		}
		if pid := strings.TrimSpace(jsonutil.StringFromAny(info["id"])); pid != "" {
			item["source_playlist_id"] = pid
		}
		if thumb := strings.TrimSpace(jsonutil.StringFromAny(info["thumbnail"])); thumb != "" {
			item["image"] = soundcloudImageMap(thumb)
		}
		items = append(items, item)
		if len(items) >= limit {
			break
		}
	}
	if len(items) == 0 {
		return []map[string]any{}, nil
	}
	return []map[string]any{{"items": items}}, nil
}

func (c *Client) GetMetadata(ctx context.Context, item, mediaType string) (map[string]any, error) {
	if !c.loggedIn {
		return nil, errors.New("soundcloud client not logged in")
	}

	switch mediaType {
	case "track":
		info, err := c.trackInfo(ctx, item)
		if err != nil {
			return nil, err
		}
		return trackMetadataFromInfo(item, info), nil
	case "playlist":
		root, err := c.playlistInfo(ctx, item)
		if err != nil {
			return nil, err
		}
		tracks := make([]any, 0)
		for i, raw := range asAnySlice(root["entries"]) {
			entry, ok := raw.(map[string]any)
			if !ok {
				continue
			}
			id := canonicalSoundcloudURL(entry)
			if id == "" {
				continue
			}
			track := map[string]any{"id": id}
			if trackID := strings.TrimSpace(jsonutil.StringFromAny(entry["id"])); trackID != "" {
				track["source_track_id"] = trackID
			}
			if title := strings.TrimSpace(jsonutil.StringFromAny(entry["title"])); title != "" {
				track["title"] = title
			}
			if artist := strings.TrimSpace(jsonutil.FirstNonEmpty(jsonutil.StringFromAny(entry["uploader"]), jsonutil.StringFromAny(entry["channel"]))); artist != "" {
				artistMap := map[string]any{"name": artist}
				if artistID := strings.TrimSpace(jsonutil.FirstNonEmpty(jsonutil.StringFromAny(entry["uploader_id"]), jsonutil.StringFromAny(entry["channel_id"]))); artistID != "" {
					artistMap["id"] = artistID
				}
				track["artist"] = artistMap
			}
			track["track_number"] = i + 1
			tracks = append(tracks, track)
		}
		name := strings.TrimSpace(jsonutil.StringFromAny(root["title"]))
		if name == "" {
			name = "SoundCloud Playlist"
		}
		meta := map[string]any{
			"id":          jsonutil.FirstNonEmpty(canonicalSoundcloudURL(root), item),
			"name":        name,
			"description": strings.TrimSpace(jsonutil.StringFromAny(root["description"])),
			"tracks":      map[string]any{"items": tracks},
		}
		if pid := strings.TrimSpace(jsonutil.StringFromAny(root["id"])); pid != "" {
			meta["source_playlist_id"] = pid
		}
		if artist := strings.TrimSpace(jsonutil.FirstNonEmpty(jsonutil.StringFromAny(root["uploader"]), jsonutil.StringFromAny(root["channel"]))); artist != "" {
			meta["artist"] = map[string]any{"name": artist}
		}
		if thumb := strings.TrimSpace(jsonutil.StringFromAny(root["thumbnail"])); thumb != "" {
			meta["image"] = soundcloudImageMap(thumb)
		}
		if entries := asAnySlice(root["entries"]); len(entries) > 0 {
			meta["tracks_count"] = len(entries)
		}
		return meta, nil
	default:
		return nil, fmt.Errorf("%w: %s", errUnsupportedMediaType, mediaType)
	}
}

func (c *Client) GetDownloadable(ctx context.Context, item string, _ int) (*provider.Downloadable, error) {
	if !c.loggedIn {
		return nil, errors.New("soundcloud client not logged in")
	}
	info, err := c.trackInfo(ctx, item)
	if err != nil {
		return nil, err
	}
	streamURL := strings.TrimSpace(jsonutil.StringFromAny(info["url"]))
	if streamURL == "" {
		return nil, errors.New("yt-dlp output missing url (track may be unavailable or region-restricted)")
	}
	ext := strings.TrimSpace(jsonutil.StringFromAny(info["ext"]))
	if ext == "" {
		ext = "m4a"
	}
	return &provider.Downloadable{URL: streamURL, Extension: ext, Source: "soundcloud"}, nil
}

func (c *Client) Close() error {
	return nil
}

func (c *Client) trackInfo(ctx context.Context, item string) (map[string]any, error) {
	if strings.TrimSpace(item) == "" {
		return nil, errors.New("empty soundcloud item")
	}

	c.mu.Lock()
	if cached, ok := c.cache[item]; ok {
		copied := cloneMap(cached)
		c.mu.Unlock()
		return copied, nil
	}
	c.mu.Unlock()

	b, err := c.run(ctx, c.bin, "-J", "--no-playlist", "--skip-download", "--no-warnings", item)
	if err != nil {
		return nil, err
	}
	info, err := parseJSONMap(b)
	if err != nil {
		return nil, err
	}
	canonical := canonicalSoundcloudURL(info)

	c.mu.Lock()
	c.cache[item] = cloneMap(info)
	if canonical != "" {
		c.cache[canonical] = cloneMap(info)
	}
	c.mu.Unlock()

	return info, nil
}

func (c *Client) playlistInfo(ctx context.Context, item string) (map[string]any, error) {
	b, err := c.run(ctx, c.bin, "-J", "--flat-playlist", "--skip-download", "--no-warnings", item)
	if err != nil {
		return nil, err
	}
	return parseJSONMap(b)
}

func trackMetadataFromInfo(id string, info map[string]any) map[string]any {
	canonicalID := jsonutil.FirstNonEmpty(canonicalSoundcloudURL(info), id)
	publisher := jsonutil.NestedMap(info, "publisher_metadata")
	title := strings.TrimSpace(jsonutil.StringFromAny(info["title"]))
	if title == "" {
		title = canonicalID
	}
	albumTitle := strings.TrimSpace(jsonutil.StringFromAny(publisher["album_title"]))
	if albumTitle == "" {
		albumTitle = strings.TrimSpace(jsonutil.StringFromAny(info["album"]))
	}
	if albumTitle == "" {
		albumTitle = title
	}
	artistName := strings.TrimSpace(jsonutil.StringFromAny(info["artist"]))
	if artistName == "" {
		artistName = strings.TrimSpace(jsonutil.StringFromAny(publisher["artist"]))
	}
	if artistName == "" {
		artistName = strings.TrimSpace(jsonutil.StringFromAny(info["uploader"]))
	}
	if artistName == "" {
		artistName = strings.TrimSpace(jsonutil.StringFromAny(info["channel"]))
	}
	artistID := strings.TrimSpace(jsonutil.FirstNonEmpty(
		jsonutil.StringFromAny(info["uploader_id"]),
		jsonutil.StringFromAny(info["channel_id"]),
		jsonutil.StringFromAny(jsonutil.NestedMap(info, "user")["id"]),
	))

	trackNum := jsonutil.IntFromAny(info["track_number"])
	if trackNum <= 0 {
		trackNum = 1
	}

	meta := map[string]any{
		"id":           canonicalID,
		"title":        title,
		"track_number": trackNum,
		"artist":       map[string]any{"name": artistName, "id": artistID},
		"performer":    map[string]any{"name": artistName, "id": artistID},
		"album": map[string]any{
			"id":     jsonutil.FirstNonEmpty(strings.TrimSpace(jsonutil.StringFromAny(info["album"])), canonicalID),
			"title":  albumTitle,
			"artist": map[string]any{"name": artistName, "id": artistID},
		},
		"description": strings.TrimSpace(jsonutil.StringFromAny(info["description"])),
		"genre":       strings.TrimSpace(jsonutil.StringFromAny(info["genre"])),
		"isrc":        strings.TrimSpace(jsonutil.StringFromAny(info["isrc"])),
		"label":       strings.TrimSpace(jsonutil.FirstNonEmpty(jsonutil.StringFromAny(info["label"]), jsonutil.StringFromAny(info["label_name"]))),
		"copyright":   strings.TrimSpace(jsonutil.StringFromAny(publisher["p_line"])),
		"release_date": strings.TrimSpace(jsonutil.FirstNonEmpty(
			jsonutil.StringFromAny(info["created_at"]),
			jsonutil.StringFromAny(info["release_date"]),
			jsonutil.StringFromAny(info["upload_date"]),
		)),
	}
	if trackID := strings.TrimSpace(jsonutil.StringFromAny(info["id"])); trackID != "" {
		meta["source_track_id"] = trackID
	}

	if jsonutil.BoolFromAny(publisher["explicit"]) || jsonutil.IntFromAny(info["age_limit"]) >= 18 {
		meta["explicit"] = true
	}

	if meta["release_date"] == "" {
		delete(meta, "release_date")
	}

	if thumb := strings.TrimSpace(jsonutil.StringFromAny(info["thumbnail"])); thumb != "" {
		meta["image"] = soundcloudImageMap(thumb)
	}

	if strings.TrimSpace(jsonutil.StringFromAny(info["album"])) == "" && strings.TrimSpace(jsonutil.StringFromAny(publisher["album_title"])) == "" {
		meta["album"] = map[string]any{
			"id":     canonicalID,
			"title":  title,
			"artist": map[string]any{"name": artistName, "id": artistID},
		}
	}

	if durationSec := jsonutil.IntFromAny(info["duration"]); durationSec > 0 {
		meta["duration"] = durationSec
	}

	return meta
}

func canonicalSoundcloudURL(info map[string]any) string {
	for _, key := range []string{"webpage_url", "original_url", "url"} {
		raw := strings.TrimSpace(jsonutil.StringFromAny(info[key]))
		if raw == "" {
			continue
		}
		u, err := url.Parse(raw)
		if err != nil {
			continue
		}
		host := strings.ToLower(strings.TrimPrefix(u.Host, "www."))
		if host != "soundcloud.com" && !strings.HasSuffix(host, ".soundcloud.com") {
			continue
		}
		u.Scheme = "https"
		u.Host = "soundcloud.com"
		u.RawQuery = ""
		u.Fragment = ""
		u.Path = strings.TrimSuffix(u.Path, "/")
		if strings.TrimSpace(u.Path) == "" {
			continue
		}
		return u.String()
	}
	return ""
}

func parseJSONMap(b []byte) (map[string]any, error) {
	var out map[string]any
	if err := json.Unmarshal(b, &out); err != nil {
		return nil, err
	}
	if out == nil {
		return nil, errors.New("empty json payload")
	}
	return out, nil
}

func cloneMap(in map[string]any) map[string]any {
	out := make(map[string]any, len(in))
	for k, v := range in {
		out[k] = v
	}
	return out
}

func asAnySlice(v any) []any {
	items, ok := v.([]any)
	if !ok {
		return nil
	}
	return items
}

func soundcloudImageMap(raw string) map[string]any {
	base := strings.TrimSpace(raw)
	if base == "" {
		return map[string]any{}
	}
	large := strings.Replace(base, "-large.", "-t500x500.", 1)
	if large == base {
		large = strings.Replace(base, "large", "t500x500", 1)
	}
	return map[string]any{
		"small":      base,
		"large":      large,
		"extralarge": large,
		"original":   large,
	}
}

func runCommand(ctx context.Context, name string, args ...string) ([]byte, error) {
	cmd := exec.CommandContext(ctx, name, args...)
	b, err := cmd.CombinedOutput()
	if err != nil {
		return nil, fmt.Errorf("command %s failed: %w: %s", name, err, string(b))
	}
	return b, nil
}