package deezer

import (
	"context"
	"encoding/json"
	"errors"
	"fmt"
	"io"
	"net/http"
	"net/url"
	"strconv"
	"strings"
	"time"

	"streamrip-go/internal/config"
	"streamrip-go/internal/netutil"
	"streamrip-go/internal/provider"
	"streamrip-go/internal/ratelimit"
)

var (
	baseURL    = "https://api.deezer.com"
	webGWLight = "https://www.deezer.com/ajax/gw-light.php"
	mediaURL   = "https://media.deezer.com/v1/get_url"
	deezerUA   = "Deezer/9.0.11.4 (Android; 14; Mobile; us) Xiaomi Redmi Note 7"
)

type Client struct {
	cfg      *config.Config
	http     *http.Client
	limiter  *ratelimit.Limiter
	loggedIn bool
	sid      string
	arl      string
	jwt      string
	refresh  string
	license  string
	userID   string
}

func New(cfg *config.Config) *Client {
	return &Client{
		cfg:     cfg,
		http:    netutil.NewHTTPClient(30*time.Second, cfg.Session.Downloads.VerifySSL),
		limiter: ratelimit.New(cfg.Session.Downloads.RequestsPerMinute),
		arl:     strings.TrimSpace(cfg.Session.Deezer.ARL),
	}
}

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

func (c *Client) Login(ctx context.Context) error {
	c.arl = strings.TrimSpace(c.cfg.Session.Deezer.ARL)
	if c.arl != "" {
		if err := c.refreshSessionFromARL(ctx); err != nil {
			return err
		}
	}
	c.loggedIn = true
	return nil
}

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

func (c *Client) Close() error {
	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("deezer client not logged in")
	}
	if limit <= 0 {
		limit = 25
	}

	pathType := mediaType
	if mediaType == "playlist" {
		pathType = "playlist"
	}
	params := url.Values{}
	params.Set("q", query)
	params.Set("limit", strconv.Itoa(limit))

	resp, err := c.apiGet(ctx, "/search/"+pathType, params)
	if err != nil {
		return nil, err
	}
	data, _ := resp["data"].([]any)
	if len(data) == 0 {
		return []map[string]any{}, nil
	}

	bucket := map[string]any{"items": data}
	return []map[string]any{{mediaType + "s": bucket}}, nil
}

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

	switch mediaType {
	case "track":
		resp, err := c.apiGet(ctx, "/track/"+item, nil)
		if err != nil {
			return nil, err
		}
		enrichTrack(resp)
		return resp, nil
	case "album":
		resp, err := c.apiGet(ctx, "/album/"+item, nil)
		if err != nil {
			return nil, err
		}
		items := make([]any, 0)
		if tracks, ok := resp["tracks"].(map[string]any); ok {
			if data, ok := tracks["data"].([]any); ok {
				for _, raw := range data {
					itm, ok := raw.(map[string]any)
					if !ok {
						continue
					}
					enrichTrack(itm)
					items = append(items, itm)
				}
			}
		}
		resp["tracks"] = map[string]any{"items": items}
		enrichAlbumImage(resp)
		return resp, nil
	case "playlist":
		resp, err := c.apiGet(ctx, "/playlist/"+item, nil)
		if err != nil {
			return nil, err
		}
		items := make([]any, 0)
		if tracks, ok := resp["tracks"].(map[string]any); ok {
			if data, ok := tracks["data"].([]any); ok {
				for _, raw := range data {
					itm, ok := raw.(map[string]any)
					if !ok {
						continue
					}
					enrichTrack(itm)
					items = append(items, itm)
				}
			}
		}
		resp["tracks"] = map[string]any{"items": items}
		return resp, nil
	case "artist":
		resp, err := c.apiGet(ctx, "/artist/"+item+"/albums", nil)
		if err != nil {
			return nil, err
		}
		albums := make([]any, 0)
		if data, ok := resp["data"].([]any); ok {
			for _, raw := range data {
				itm, ok := raw.(map[string]any)
				if !ok {
					continue
				}
				enrichAlbumImage(itm)
				albums = append(albums, itm)
			}
		}
		return map[string]any{"name": "", "albums": map[string]any{"items": albums}}, nil
	default:
		return nil, fmt.Errorf("unsupported deezer media type: %s", mediaType)
	}
}

func (c *Client) GetDownloadable(ctx context.Context, item string, _ int) (*provider.Downloadable, error) {
	if strings.TrimSpace(c.arl) == "" {
		return nil, errors.New("deezer native download requires deezer.arl in config")
	}
	if strings.TrimSpace(c.license) == "" {
		if err := c.refreshSessionFromARL(ctx); err != nil {
			return nil, err
		}
	}
	meta, err := c.GetMetadata(ctx, item, "track")
	if err != nil {
		return nil, err
	}
	trackToken := strings.TrimSpace(stringFromAny(meta["track_token"]))
	if trackToken == "" {
		trackToken, err = c.getTrackToken(ctx, item)
		if err != nil {
			return nil, err
		}
	}
	media, err := c.getMediaURL(ctx, trackToken, c.cfg.Session.Deezer.Quality, c.cfg.Session.Deezer.LowerQualityIfNotAvailable)
	if err != nil {
		return nil, err
	}
	ext := extensionForFormat(media.Format)
	if ext == "" {
		ext = "mp3"
	}
	trackID := strings.TrimSpace(stringFromAny(meta["id"]))
	if trackID == "" {
		trackID = strings.TrimSpace(item)
	}
	return &provider.Downloadable{URL: media.URL, Extension: ext, Source: "deezer", Cipher: media.Cipher, TrackID: trackID}, nil
}

func (c *Client) apiGet(ctx context.Context, path string, params url.Values) (map[string]any, error) {
	if err := c.limiter.Wait(ctx); err != nil {
		return nil, err
	}

	u := strings.TrimSuffix(baseURL, "/") + "/" + strings.TrimPrefix(path, "/")
	if len(params) > 0 {
		u += "?" + params.Encode()
	}
	req, err := http.NewRequestWithContext(ctx, http.MethodGet, u, nil)
	if err != nil {
		return nil, err
	}
	req.Header.Set("User-Agent", "streamrip-go/0.1")

	resp, err := c.http.Do(req)
	if err != nil {
		return nil, err
	}
	defer func() { _ = resp.Body.Close() }()
	body, err := io.ReadAll(resp.Body)
	if err != nil {
		return nil, err
	}
	out := map[string]any{}
	if len(body) > 0 {
		if err = json.Unmarshal(body, &out); err != nil {
			return nil, err
		}
	}
	if resp.StatusCode < 200 || resp.StatusCode >= 300 {
		return nil, fmt.Errorf("deezer api failed: status=%d body=%s", resp.StatusCode, string(body))
	}
	if errObj, ok := out["error"].(map[string]any); ok {
		msg := strings.TrimSpace(stringFromAny(errObj["message"]))
		if msg == "" {
			msg = strings.TrimSpace(stringFromAny(errObj["type"]))
		}
		if msg == "" {
			msg = "unknown deezer error"
		}
		return nil, fmt.Errorf("deezer api error: %s", msg)
	}
	return out, nil
}

func (c *Client) refreshSessionFromARL(ctx context.Context) error {
	if strings.TrimSpace(c.arl) == "" {
		return errors.New("missing deezer arl")
	}
	if err := c.limiter.Wait(ctx); err != nil {
		return err
	}
	params := url.Values{}
	params.Set("method", "deezer.getUserData")
	params.Set("input", "3")
	params.Set("api_version", "1.0")
	params.Set("api_token", "")

	req, err := http.NewRequestWithContext(ctx, http.MethodGet, webGWLight+"?"+params.Encode(), nil)
	if err != nil {
		return err
	}
	req.Header.Set("User-Agent", deezerUA)
	req.Header.Set("Accept", "application/json")
	req.Header.Set("Cookie", "arl="+strings.TrimSpace(c.arl))

	resp, err := c.http.Do(req)
	if err != nil {
		return err
	}
	defer func() { _ = resp.Body.Close() }()
	raw, err := io.ReadAll(resp.Body)
	if err != nil {
		return err
	}
	if resp.StatusCode < 200 || resp.StatusCode >= 300 {
		return fmt.Errorf("deezer getUserData failed: status=%d body=%s", resp.StatusCode, string(raw))
	}
	out := map[string]any{}
	if err = json.Unmarshal(raw, &out); err != nil {
		return err
	}
	if errObj, ok := out["error"].(map[string]any); ok && len(errObj) > 0 {
		return fmt.Errorf("deezer getUserData error: %s", stringFromAny(errObj["message"]))
	}
	results, _ := out["results"].(map[string]any)
	if len(results) == 0 {
		return errors.New("deezer getUserData returned empty results")
	}
	c.license = findStringByKey(results, "license_token")
	c.userID = findStringByKey(results, "USER_ID")
	if c.license == "" {
		return errors.New("deezer getUserData missing license_token")
	}
	return nil
}

func (c *Client) getTrackToken(ctx context.Context, trackID string) (string, error) {
	resp, err := c.apiGet(ctx, "/track/"+url.PathEscape(strings.TrimSpace(trackID)), nil)
	if err != nil {
		return "", err
	}
	token := strings.TrimSpace(stringFromAny(resp["track_token"]))
	if token == "" {
		return "", errors.New("deezer track metadata missing track_token")
	}
	return token, nil
}

type mediaResult struct {
	URL    string
	Format string
	Cipher string
}

func (c *Client) getMediaURL(ctx context.Context, trackToken string, quality int, allowFallback bool) (*mediaResult, error) {
	requestedFormats := buildFormatPriority(quality, allowFallback)
	var lastErr error
	for _, format := range requestedFormats {
		result, err := c.getMediaURLForFormat(ctx, trackToken, format)
		if err == nil {
			return result, nil
		}
		lastErr = err
		if !allowFallback {
			break
		}
	}
	if lastErr != nil {
		return nil, lastErr
	}
	return nil, errors.New("deezer media response contains no playable variants")
}

func (c *Client) getMediaURLForFormat(ctx context.Context, trackToken, format string) (*mediaResult, error) {
	if strings.TrimSpace(c.license) == "" {
		return nil, errors.New("missing deezer license token")
	}
	if err := c.limiter.Wait(ctx); err != nil {
		return nil, err
	}

	reqBody := map[string]any{
		"license_token": c.license,
		"track_tokens":  []string{trackToken},
		"media": []map[string]any{{
			"type":    "FULL",
			"formats": []map[string]string{{"cipher": "BF_CBC_STRIPE", "format": format}, {"cipher": "NONE", "format": format}},
		}},
	}
	b, err := json.Marshal(reqBody)
	if err != nil {
		return nil, err
	}
	req, err := http.NewRequestWithContext(ctx, http.MethodPost, mediaURL, strings.NewReader(string(b)))
	if err != nil {
		return nil, err
	}
	req.Header.Set("User-Agent", deezerUA)
	req.Header.Set("Accept", "*/*")
	req.Header.Set("Content-Type", "text/plain; charset=UTF-8")

	resp, err := c.http.Do(req)
	if err != nil {
		return nil, err
	}
	defer func() { _ = resp.Body.Close() }()
	raw, err := io.ReadAll(resp.Body)
	if err != nil {
		return nil, err
	}
	if resp.StatusCode < 200 || resp.StatusCode >= 300 {
		return nil, fmt.Errorf("deezer media get_url failed: status=%d body=%s", resp.StatusCode, string(raw))
	}
	var parsed struct {
		Data []struct {
			Errors []struct {
				Code    int    `json:"code"`
				Message string `json:"message"`
			} `json:"errors"`
			Media []struct {
				Cipher struct {
					Type string `json:"type"`
				} `json:"cipher"`
				Format  string `json:"format"`
				Sources []struct {
					URL string `json:"url"`
				} `json:"sources"`
			} `json:"media"`
		} `json:"data"`
	}
	if err = json.Unmarshal(raw, &parsed); err != nil {
		return nil, err
	}
	if len(parsed.Data) == 0 {
		return nil, errors.New("deezer media response contains no data")
	}
	if len(parsed.Data[0].Errors) > 0 {
		e := parsed.Data[0].Errors[0]
		if strings.Contains(strings.ToLower(e.Message), "drm") {
			return nil, errors.New("deezer media is DRM protected for this format/account")
		}
		return nil, fmt.Errorf("deezer media error %d: %s", e.Code, e.Message)
	}
	for _, m := range parsed.Data[0].Media {
		if len(m.Sources) == 0 || strings.TrimSpace(m.Sources[0].URL) == "" {
			continue
		}
		return &mediaResult{URL: m.Sources[0].URL, Format: m.Format, Cipher: m.Cipher.Type}, nil
	}
	return nil, errors.New("deezer media response contains no sources")
}

func buildFormatPriority(quality int, allowFallback bool) []string {
	want := "FLAC"
	if quality <= 0 {
		want = "MP3_128"
	} else if quality == 1 {
		want = "MP3_320"
	}
	priority := []string{want}
	if allowFallback {
		for _, f := range []string{"FLAC", "MP3_320", "MP3_128"} {
			if f != want {
				priority = append(priority, f)
			}
		}
	}
	return priority
}

func extensionForFormat(format string) string {
	switch strings.ToUpper(strings.TrimSpace(format)) {
	case "FLAC":
		return "flac"
	case "MP3_320", "MP3_128", "MP3_64", "MP3_MISC":
		return "mp3"
	default:
		return "mp3"
	}
}

func findStringByKey(v any, wantedKey string) string {
	w := strings.ToLower(strings.TrimSpace(wantedKey))
	switch x := v.(type) {
	case map[string]any:
		for k, value := range x {
			if strings.ToLower(k) == w {
				if s := stringFromAny(value); strings.TrimSpace(s) != "" {
					return s
				}
			}
			if nested := findStringByKey(value, wantedKey); nested != "" {
				return nested
			}
		}
	case []any:
		for _, item := range x {
			if nested := findStringByKey(item, wantedKey); nested != "" {
				return nested
			}
		}
	}
	return ""
}

func enrichTrack(track map[string]any) {
	if artist, ok := track["artist"].(map[string]any); ok {
		track["performer"] = map[string]any{"name": stringFromAny(artist["name"]), "id": stringFromAny(artist["id"])}
	}
	if album, ok := track["album"].(map[string]any); ok {
		enrichAlbumImage(album)
	}
	if _, ok := track["track_number"]; !ok {
		if p := track["track_position"]; p != nil {
			track["track_number"] = p
		}
	}
	if _, ok := track["media_number"]; !ok {
		if d := track["disk_number"]; d != nil {
			track["media_number"] = d
		}
	}
	if boolFromAny(track["explicit_lyrics"]) {
		track["explicit"] = true
	}
}

func enrichAlbumImage(meta map[string]any) {
	if _, ok := meta["image"].(map[string]any); ok {
		return
	}
	cover := firstNonEmpty(
		stringFromAny(meta["cover_xl"]),
		stringFromAny(meta["cover_big"]),
		stringFromAny(meta["cover_medium"]),
		stringFromAny(meta["cover_small"]),
	)
	if cover == "" {
		return
	}
	meta["image"] = map[string]any{
		"small":      cover,
		"large":      cover,
		"extralarge": cover,
		"original":   cover,
	}
}

func stringFromAny(v any) string {
	switch t := v.(type) {
	case string:
		return t
	case int:
		return strconv.Itoa(t)
	case int64:
		return strconv.FormatInt(t, 10)
	case float64:
		return strconv.FormatFloat(t, 'f', -1, 64)
	default:
		return ""
	}
}

func firstNonEmpty(items ...string) string {
	for _, item := range items {
		if strings.TrimSpace(item) != "" {
			return strings.TrimSpace(item)
		}
	}
	return ""
}

func intFromAny(v any) int {
	switch t := v.(type) {
	case int:
		return t
	case int64:
		return int(t)
	case float64:
		return int(t)
	case string:
		i, _ := strconv.Atoi(strings.TrimSpace(t))
		return i
	default:
		return 0
	}
}

func boolFromAny(v any) bool {
	b, ok := v.(bool)
	return ok && b
}