package youtube

import (
	"bytes"
	"encoding/json"
	"fmt"
	"net/http"
	"net/url"

	"github.com/grafov/m3u8"
)

type Client struct {
	InnertubeClient *InnertubeClient
	HTTPClient      *http.Client
}

type InnertubeClient struct {
	Key           string `json:"-"`
	HDRClientName string `json:"-"`
	HL            string `json:"hl,omitempty"`
	GL            string `json:"gl,omitempty"`
	ClientName    string `json:"clientName,omitempty"`
	ClientVersion string `json:"clientVersion,omitempty"`
	DeviceModel   string `json:"deviceModel,omitempty"`
	UserAgent     string `json:"userAgent,omitempty"`
	TimeZone      string `json:"timeZone,omitempty"`
	UTCOffsetMins int64  `json:"utcOffsetMinutes,omitempty"`
}

type innertubeRequest struct {
	VideoID      string `json:"videoId,omitempty"`
	BrowseID     string `json:"browseId,omitempty"`
	Continuation string `json:"continuation,omitempty"`
	Context      struct {
		Client InnertubeClient `json:"client"`
	} `json:"context"`
	PlaybackContext struct {
		ContentPlaybackContext struct {
			HTML5Preference string `json:"html5Preference"`
		} `json:"contentPlaybackContext"`
	} `json:"playbackContext,omitempty"`
	ContentCheckOK bool   `json:"contentCheckOk,omitempty"`
	RacyCheckOk    bool   `json:"racyCheckOk,omitempty"`
	Params         string `json:"params"`
}

var (
	IOSClient = InnertubeClient{
		Key:           "AIzaSyAOghZGza2MQSZkY_zfZ370N-PUdXEo8AI",
		HDRClientName: "5",
		HL:            "en",
		GL:            "US",
		ClientName:    "IOS",
		ClientVersion: "17.33.2",
		DeviceModel:   "iPhone14,3",
		UserAgent:     "com.google.ios.youtube/17.33.2 (iPhone14,3; U; CPU iOS 15_6 like Mac OS X)",
		TimeZone:      "UTC",
		UTCOffsetMins: 0,
	}
)

var DefaultClient = IOSClient

func New() *Client {
	client := new(Client)

	client.HTTPClient = &http.Client{}
	client.InnertubeClient = &DefaultClient

	return client
}

func (c Client) GetVideoFromID(id string) (out Video, err error) {
	uri, _ := url.Parse("https://www.youtube.com/youtubei/v1/player")
	q := uri.Query()
	q.Add("key", c.InnertubeClient.Key)
	uri.RawQuery = q.Encode()

	reqData := new(innertubeRequest)
	reqData.Context.Client = *c.InnertubeClient
	reqData.VideoID = id
	reqData.ContentCheckOK = true
	reqData.RacyCheckOk = true
	reqData.Params = "CgIQBg=="
	reqData.PlaybackContext.ContentPlaybackContext.HTML5Preference = "HTML5_PREF_WANTS"

	reqBody, err := json.Marshal(reqData)
	if err != nil {
		return
	}

	payload := bytes.NewReader(reqBody)
	req, err := http.NewRequest("POST", uri.String(), payload)

	if err != nil {
		fmt.Println(err)
		return
	}
	req.Header.Add("User-Agent", c.InnertubeClient.UserAgent)
	req.Header.Add("X-YouTube-Client-Name", c.InnertubeClient.HDRClientName)
	req.Header.Add("X-YouTube-Client-Version", c.InnertubeClient.ClientVersion)
	req.Header.Add("Content-Type", "application/json")

	res, err := c.HTTPClient.Do(req)
	if err != nil {
		fmt.Println(err)
		return
	}
	defer res.Body.Close()

	json.NewDecoder(res.Body).Decode(&out)

	return
}

func (v Video) GetHLSPlaylist(itag string) (out string) {
	resp, err := http.Get(v.StreamingData.HlsManifestURL)
	if err != nil {
		return
	}

	defer resp.Body.Close()

	p, _, err := m3u8.DecodeFrom(resp.Body, true)
	if err != nil {
		return
	}

	pl := p.(*m3u8.MasterPlaylist)
	for _, variant := range pl.Variants {
		if len(variant.Alternatives) > 0 {
			for _, a := range variant.Alternatives {
				if a.GroupId == itag {
					return a.URI
				}
			}
		}
	}

	return
}