package youtube

import (
	"errors"
	"fmt"
	"log"
	"net/http"
	"net/url"
	"strings"
	"time"

	iso8601duration "github.com/ChannelMeter/iso8601duration"
	"github.com/icedream/irc-medialink/parsers"
	"google.golang.org/api/googleapi/transport"
	"google.golang.org/api/youtube/v3"
)

const (
	youtubeIdType_None youtubeIdType = iota
	youtubeIdType_Video
	youtubeIdType_ChannelName
	youtubeIdType_ChannelId
	youtubeIdType_Playlist

	header = "\x031,0You\x030,4Tube\x03" +
		"99,99" + /* Fix for KiwiIRC not flushing background color on empty color tag */
		"\x03" /* Fix for Mibbit interpreting 99 as green instead of transparent */
)

var (
	ErrNotFound = errors.New("Not found.")
)

type youtubeIdType uint8

type Parser struct {
	Config  *Config
	Service *youtube.Service
}

func getYouTubeId(uri *url.URL, followRedirects int) (youtubeIdType, string) {
	u := &(*uri)
	u.Scheme = strings.ToLower(u.Scheme)
	u.Host = strings.ToLower(u.Host)

	// Must be an HTTP URL
	if u.Scheme != "http" && u.Scheme != "https" {
		return youtubeIdType_None, ""
	}

	// Remove www. prefix from hostname
	if strings.HasPrefix(u.Host, "www.") {
		u.Host = u.Host[4:]
	}

	switch strings.ToLower(u.Host) {
	case "youtu.be":
		// http://youtu.be/{id}
		if s, err := url.QueryUnescape(strings.TrimLeft(u.Path, "/")); err == nil {
			return youtubeIdType_Video, s
		}
	case "youtube.com":
		if u.Path == "/watch" {
			// http://youtube.com/watch?v={id}
			return youtubeIdType_Video, u.Query().Get("v")
		} else if strings.HasPrefix(u.Path, "/channel/") {
			// https://www.youtube.com/channel/{channelid}
			return youtubeIdType_ChannelId, strings.Trim(u.Path[9:], "/")
		} else if strings.HasPrefix(u.Path, "/c/") {
			// http://youtube.com/c/{channelname}
			return youtubeIdType_ChannelName, strings.Trim(u.Path[3:], "/")
		} else if strings.HasPrefix(u.Path, "/user/") {
			// http://youtube.com/user/{channelname}
			return youtubeIdType_ChannelName, strings.Trim(u.Path[6:], "/")
		} else if strings.HasPrefix(u.Path, "/playlist") {
			// https://www.youtube.com/playlist?list=PLq34c5GJGiJJlrG9-ByMbuQkTvaFtIflO
			return youtubeIdType_Playlist, u.Query().Get("list")
		} else if followRedirects > 0 && len(u.Path) > 1 && !strings.Contains(u.Path[1:], "/") {
			// Maybe https://youtube.com/{channelname}.
			// Does this actually redirect to a channel?
			req, err := http.NewRequest("HEAD", u.String(), nil)
			if err != nil {
				log.Printf("Failed to create HEAD request from %s: %s", u, err)
				return youtubeIdType_None, ""
			}
			resp, err := http.DefaultTransport.RoundTrip(req)
			if err != nil {
				log.Printf("Failed to check for channel from %s: %s", u, err)
				return youtubeIdType_None, ""
			}
			if resp.StatusCode >= 300 && resp.StatusCode < 400 {
				if lu, err := resp.Location(); err == nil && lu != nil {
					return getYouTubeId(lu, followRedirects-1)
				}
			}
		}
	}

	return youtubeIdType_None, ""
}

func (p *Parser) Init() error {
	// youtube api
	client := &http.Client{
		Transport: &transport.APIKey{Key: p.Config.ApiKey},
	}
	if srv, err := youtube.New(client); err != nil {
		return err
	} else {
		p.Service = srv
	}
	return nil
}

func (p *Parser) Name() string {
	return "YouTube"
}

func (p *Parser) Parse(u *url.URL, referer *url.URL) (result parsers.ParseResult) {
	// Parse YouTube URL
	idType, id := getYouTubeId(u, 2)
	if idType == youtubeIdType_None {
		result.Ignored = true
		return // nothing relevant found in this URL
	}

	switch idType {
	case youtubeIdType_Video:
		// Get YouTube video info
		list, err := p.Service.Videos.List("contentDetails,id,liveStreamingDetails,snippet,statistics").Id(id).Do()
		if err != nil {
			result.Error = err
			return
		}

		// Any info available?
		if len(list.Items) < 1 {
			result.UserError = ErrNotFound
			return
		}

		// Collect information
		result.Information = []map[string]interface{}{}
		for _, item := range list.Items {
			r := map[string]interface{}{
				"ShortUrl": fmt.Sprintf("https://youtu.be/%v", url.QueryEscape(item.Id)),
				"IsUpload": true,
				"IsLive":   item.LiveStreamingDetails != nil,
			}
			if item.Snippet != nil {
				r["Title"] = item.Snippet.Title
				r["Author"] = item.Snippet.ChannelTitle
				r["Description"] = item.Snippet.Description
				r["Category"] = item.Snippet.CategoryId
				r["Tags"] = item.Snippet.Tags

				// parse publishedAt
				if t, err := time.Parse(time.RFC3339, item.Snippet.PublishedAt); err == nil {
					r["PublishedAt"] = t
				} else {
					log.Print(err)
				}
			}
			if item.ContentDetails != nil {
				// parse duration
				if d, err := iso8601duration.FromString(item.ContentDetails.Duration); err == nil {
					r["Duration"] = d.ToDuration()
				} else {
					log.Print(err)
				}
			}
			if item.Statistics != nil {
				r["Views"] = item.Statistics.ViewCount
				r["Comments"] = item.Statistics.CommentCount
				r["Likes"] = item.Statistics.LikeCount
				r["Dislikes"] = item.Statistics.DislikeCount
				r["Favorites"] = item.Statistics.FavoriteCount
			}
			/*if item.LiveStreamingDetails != nil {
				r["Views"] = item.LiveStreamingDetails.ConcurrentViewers
			}*/
			r["Header"] = header
			result.Information = append(result.Information, r)
		}
	case youtubeIdType_ChannelId, youtubeIdType_ChannelName:
		// Get YouTube channel info
		cl := p.Service.Channels.List("id,snippet,statistics")
		if idType == youtubeIdType_ChannelName {
			cl = cl.ForUsername(id)
		} else {
			cl = cl.Id(id)
		}
		list, err := cl.Do()
		if err != nil {
			result.Error = err
			return
		}

		// Any info available?
		if len(list.Items) < 1 {
			result.UserError = ErrNotFound
			return
		}

		// Collect information
		result.Information = []map[string]interface{}{}
		for _, item := range list.Items {
			r := map[string]interface{}{
				"Header":      header,
				"IsProfile":   true,
				"Title":       "Channel",
				"Author":      item.Snippet.Title,
				"CountryCode": item.Snippet.Country,
				"Description": item.Snippet.Description,
				"ShortUrl":    item.Snippet.CustomUrl,
				"Comments":    item.Statistics.CommentCount,
				"Videos":      item.Statistics.VideoCount,
				"Views":       item.Statistics.ViewCount,
			}
			if !item.Statistics.HiddenSubscriberCount {
				r["Followers"] = item.Statistics.SubscriberCount
			}
			result.Information = append(result.Information, r)
		}
	case youtubeIdType_Playlist:
		// Get YouTube channel info
		list, err := p.Service.Playlists.List("id,snippet").Id(id).Do()
		if err != nil {
			result.Error = err
			return
		}

		// Any info available?
		if len(list.Items) < 1 {
			result.UserError = ErrNotFound
			return
		}

		// Collect information
		result.Information = []map[string]interface{}{}
		for _, item := range list.Items {
			r := map[string]interface{}{
				"Header":      header,
				"IsPlaylist":  true,
				"Title":       "Playlist: " + item.Snippet.Title,
				"Author":      item.Snippet.ChannelTitle,
				"PublishedAt": item.Snippet.PublishedAt,
				"Description": item.Snippet.Description,
			}

			// parse publishedAt
			if t, err := time.Parse(time.RFC3339, item.Snippet.PublishedAt); err == nil {
				r["PublishedAt"] = t
			} else {
				log.Print(err)
			}

			result.Information = append(result.Information, r)
		}
	default:
		result.Ignored = true
	}

	return
}