package ratings

import (
	"bufio"
	"bytes"
	"compress/gzip"
	"fmt"
	"io/ioutil"
	"net/http"
	"strconv"
	"strings"
	"time"

	"github.com/sirupsen/logrus"

	"git.quimbo.fr/odwrtw/canape/backend/models"
	"git.quimbo.fr/odwrtw/canape/backend/web"
)

const imdbRatingsURL = "https://datasets.imdbws.com/title.ratings.tsv.gz"

// Refresh will refresh the ImdbRatings
func Refresh(env *web.Env) error {
	log := env.Log.WithFields(logrus.Fields{
		"function": "imdbRating.Refresh",
	})

	// Download the data
	var httpClient = &http.Client{
		Timeout: time.Second * 10,
	}
	resp, err := httpClient.Get(imdbRatingsURL)
	if err != nil {
		return err
	}
	defer resp.Body.Close()

	if resp.StatusCode != http.StatusOK {
		return fmt.Errorf("got HTTP error %s", resp.Status)
	}

	// Read all the file (~5MB) in memory
	// We do that because the ~1 000 000 upserts take too long, and the IMDB
	// server will cut our connection after ~2h
	content, err := ioutil.ReadAll(resp.Body)
	if err != nil {
		return err
	}

	readerContent := bytes.NewReader(content)
	// Unzip it
	r, err := gzip.NewReader(readerContent)
	if err != nil {
		return err
	}

	tx, err := env.Database.Beginx()
	if err != nil {
		return err
	}

	// Read it
	scanner := bufio.NewScanner(r)
	for scanner.Scan() {
		elmts := strings.Split(scanner.Text(), "\t")
		if len(elmts) != 3 {
			log.Debugf("got %d elements weird", len(elmts))
			continue
		}

		rating, err := strconv.ParseFloat(elmts[1], 64)
		if err != nil {
			log.Debugf("failed to parse rating %s", elmts[1])
			continue
		}
		numVote, err := strconv.ParseInt(elmts[2], 10, 64)
		if err != nil {
			log.Debugf("failed to parse numVote %q", elmts[2])
			continue
		}

		videoRating := &models.ImdbRating{
			ImdbID: elmts[0],
			Rating: float32(rating),
			Votes:  int(numVote),
		}
		err = models.TxUpsertImdbRating(tx, videoRating)
		if err != nil {
			log.WithFields(logrus.Fields{
				"error": err,
			}).Error("got error while upserting rating, rollback!")
			if rollbackErr := tx.Rollback(); err != nil {
				log.WithFields(logrus.Fields{
					"error": rollbackErr,
				}).Error("unable to rollack")
			}
			return err
		}
	}

	return tx.Commit()
}