package cmd

import (
	"context"
	"encoding/json"
	ts "github.com/n0madic/twitter-scraper"
	"log"
	"math/rand"
	"net/http"
	"os"
	"os/signal"
	"syscall"
	"time"
)

var (
	configPath = "./config.toml"
	dbPath     = "./db/tweets.db"
	cookiePath = "./db/cookies.json"
)

const (
	ScrapeInterval int   = 3  // How often to check for new tweets (in minutes)
	ScrapeDelay    int64 = 0  // How long to wait between api requests (in seconds)
	ScrapeStep     int   = 10 // How many tweets to get at a time
)

type App struct {
	config  *Config
	db      *Database
	scraper *ts.Scraper
}

func Run() {
	args := os.Args[1:]

	if len(args) > 1 {
		log.Fatalln("Too many arguments")
	}

	if len(args) == 1 {
		if args[0] == "" {
			log.Fatalln("No config path given")
		}
		configPath = args[0]
	}

	config, err := ConfigFromFile(configPath)
	if err != nil {
		log.Fatalf("There has been an error parsing config file '%s': %s\n", configPath, err.Error())
	}

	if len(config.Channels) == 0 {
		log.Fatalln("List of channels cannot be empty")
	}

	if len(config.Channels) != len(config.Filter) {
		log.Fatalln("List of filters has to be same length as channel list")
	}

	if config.Webhook == "" {
		log.Fatalln("Webhook address cannot be empty")
	}

	if config.DbPath != "" {
		dbPath = config.DbPath
	}

	if config.CookiePath != "" {
		cookiePath = config.CookiePath
	}

	db, dberr := NewDatabase("sqlite3", dbPath)
	if dberr != nil {
		log.Fatalf("An error occurred while creating database connection: %s\n", dberr.Error())
	}
	defer db.Close()

	scraper := ts.New()

	if config.ProxyAddr != "" {
		err = scraper.SetProxy(config.ProxyAddr)
		if err != nil {
			log.Fatalf("An error occurred with proxy connection: %s\n", err.Error())
		}
	}

	{
		f, err := os.Open(cookiePath)
		if err != nil {
			log.Println("Cookie file does not yet exist")
		} else {
			var cookies []*http.Cookie
			json.NewDecoder(f).Decode(&cookies)
			scraper.SetCookies(cookies)
		}
	}

	if scraper.IsLoggedIn() {
		log.Println("We're already logged in, skipping login...")
	} else {
		scraper.ClearCookies()
		if len(config.Username) > 0 {
			err = scraper.Login(config.Username, config.Password)
			if err != nil {
				log.Fatalf("An error occurred during scraper login: %s\n", err.Error())
			} else {
				log.Printf("New Login - Saving cookies to %s\n", cookiePath)
				js, jsonErr := json.Marshal(scraper.GetCookies())
				if jsonErr != nil {
					log.Fatalf("An error occurred during cookie serialization: %s\n", jsonErr.Error())
				}
				f, fErr := os.Create(cookiePath)
				if fErr != nil {
					log.Fatalf("Failed to create cookie file at %s with the following error: %s\n", cookiePath, fErr.Error())
				}
				f.Write(js)
				writeErr := f.Close()
				if writeErr != nil {
					log.Fatalf("An error occurred on closing cookie file: %s\n", writeErr.Error())
				}
			}
		} else {
			log.Println("Trying open account login... ")
			err = scraper.LoginOpenAccount()
			if err != nil {
				log.Fatalf("An error occurred during scraper login: %s\n", err.Error())
			}
			defer scraper.Logout()
		}
	}

	scraper.WithDelay(ScrapeDelay)

	app := App{config, db, scraper}

	for i, c := range config.Channels {
		go app.queryX(i, c)
	}

	sigs := make(chan os.Signal, 1)
	signal.Notify(sigs, syscall.SIGINT, syscall.SIGTERM)
	done := make(chan bool, 1)

	go func() {
		sig := <-sigs
		log.Println(sig)
		done <- true
	}()

	<-done
	log.Println("Exiting...")
}

func (app *App) queryX(id int, channel string) {
	log.Printf("Starting worker %d for channel %s", id, channel)
	// Sleep to stagger api queries of workers
	time.Sleep(time.Duration(id) * time.Minute)

	db := app.db
	filter := app.config.Filter[id]
	init := true

ScrapeLoop:
	for {
		if !init {
			// Sleep for set interval +-30 seconds
			time.Sleep(time.Duration(ScrapeInterval)*time.Minute + time.Duration(rand.Intn(60)-30)*time.Second)
		}
		init = false

		step := ScrapeStep
		tweets := []*ts.Tweet{}
		tweetsToParse := []*ts.Tweet{}
		tweetsToPost := []*ts.Tweet{}

		dbTweets, dbErr := db.GetTweets(channel)
		if dbErr != nil {
			log.Printf("Error while retrieving tweets from database for channel %s: %s", channel, dbErr.Error())
			continue ScrapeLoop
		}

	GetTweets:
		for {
			for tweet := range app.scraper.GetTweets(context.Background(), channel, step) {
				if tweet.Error != nil {
					log.Printf("Error while retrieving tweet for channel %s: %s", channel, tweet.Error.Error())
					continue ScrapeLoop
				}
				tweets = append(tweets, &tweet.Tweet)
			}
			if len(tweets) == 0 {
				break GetTweets
			}

			if len(dbTweets) > 0 {
				for _, dbTweet := range dbTweets {
					for i, tweet := range tweets {
						if dbTweet.EqualsTweet(tweet) {
							tweetsToParse = tweets[:i]
							break GetTweets
						}
					}
				}
			} else {
				tweetsToParse = append(tweetsToParse, tweets[0])
				break GetTweets
			}

			if step >= 50 {
				tweetsToParse = append(tweetsToParse, tweets[0])
				break GetTweets
			} else if step+ScrapeStep > 50 {
				step = 50
			} else {
				step += ScrapeStep
			}

			log.Printf("Fetching more tweets for %s...", channel)
			time.Sleep(time.Duration(3) * time.Second) // Wait a few seconds for next api request
		}

	ParseTweets:
		// We want to parse old to new
		for i := len(tweetsToParse) - 1; i >= 0; i-- {
			tweet := tweetsToParse[i]
			if filterTweet(filter, tweet) {
				// One of the filters applies as same bits are 1, so we skip this tweet
				continue ParseTweets
			}

			err := db.InsertTweet(channel, tweet)
			if err != nil {
				log.Printf("Error while inserting tweet for channel %s into the database: %s", channel, err.Error())
				continue ParseTweets
			}
			tweetsToPost = append(tweetsToPost, tweet)
		}

		sendToWebhook(app.config.Webhook, tweetsToPost)
		err := db.PruneOldestTweets(channel)
		if err != nil {
			log.Printf("Error while pruning old tweets for channel %s: %s", channel, err.Error())
		}
	}
}

func filterTweet(filter uint8, tweet *ts.Tweet) bool {
	var tweetFilter uint8 = 0
	filterMap := []bool{tweet.IsSelfThread, tweet.IsRetweet, tweet.IsReply, tweet.IsPin, tweet.IsQuoted}
	for _, f := range filterMap {
		tweetFilter <<= 1
		if f {
			tweetFilter |= 1
		}
	}

	return filter&tweetFilter > 0
}