package cmd

import (
	"fmt"
	"io"
	"math/rand"
	"net/http"
	"net/url"
	"os"
	"path/filepath"
	"strings"
	"time"

	"github.com/PuerkitoBio/goquery"
	"github.com/google/uuid"
	"github.com/jzelinskie/geddit"
	"github.com/kf5grd/keybasebot"
)

func getMetaLoginCreds(b *keybasebot.Bot) (username, password string, err error) {
	user, ok := b.Meta["reddit-user"]
	if !ok {
		err = fmt.Errorf("No reddit username has been set.")
	}
	pass, ok := b.Meta["reddit-pass"]
	if !ok {
		err = fmt.Errorf("No reddit password has been set.")
	}
	username = user.(string)
	password = pass.(string)
	return
}

func getRedditSubmissions(b *keybasebot.Bot, sub string, sort string, count int) ([]*geddit.Submission, error) {
	// check the sort type
	allowedSort := map[string]bool{
		"hot":           true,
		"new":           true,
		"rising":        true,
		"top":           true,
		"controversial": true,
		"":              true,
	}
	if !allowedSort[sort] {
		return nil, fmt.Errorf("%s is not an allowed sort method", sort)
	}
	user, pass, err := getMetaLoginCreds(b)
	if err != nil {
		return nil, err
	}
	session, err := geddit.NewLoginSession(
		user,
		pass,
		"golang:pub.keybase.haukened.ssh0le:v2.0 (by /u/no-names-here)",
	)
	if err != nil {
		return nil, err
	}
	subOpts := geddit.ListingOptions{
		Limit: count,
	}
	submissions, err := session.SubredditSubmissions(sub, geddit.PopularitySort(sort), subOpts)
	if err != nil {
		return nil, err
	}
	return submissions, nil
}

func filterSubmissions(gs []*geddit.Submission, test func(*geddit.Submission) bool) (ret []*geddit.Submission) {
	for _, s := range gs {
		if test(s) {
			ret = append(ret, s)
		}
	}
	return
}

func filterMedia(gs []*geddit.Submission) (ret []*geddit.Submission) {
	test := func(s *geddit.Submission) bool {
		return strings.HasSuffix(s.URL, ".jpg") ||
			strings.HasSuffix(s.URL, ".png") ||
			strings.HasSuffix(s.URL, ".gif") ||
			strings.HasSuffix(s.URL, ".mp4")
	}
	ret = filterSubmissions(gs, test)
	return
}

func fixGfycatURL(sub *geddit.Submission) error {
	resp, err := http.Get(sub.URL)
	if err != nil {
		return err
	}
	defer resp.Body.Close()
	doc, err := goquery.NewDocumentFromReader(resp.Body)
	if err != nil {
		return err
	}
	vids := doc.Find("source")
	found := false
	for _, vid := range vids.Nodes {
		for _, element := range vid.Attr {
			if strings.HasSuffix(element.Val, ".mp4") && strings.Contains(element.Val, "-mobile") {
				sub.URL = element.Val
				found = true
				break
			}
		}
	}
	if !found {
		return fmt.Errorf("Unable to find Gfycat Video, because they suck.")
	}
	return nil
}

func downloadRedditMedia(s *geddit.Submission) (path string, err error) {
	// break down the url to get the path, less the host and any arguments or fragments
	URLParts, err := url.Parse(s.URL)
	if err != nil {
		return
	}
	// get the file extension
	ext := filepath.Ext(URLParts.Path)
	if ext == "" {
		err = fmt.Errorf("URL had no media file extension")
		return
	}
	// get the file
	response, err := http.Get(s.URL)
	if err != nil {
		return
	}
	defer response.Body.Close()
	// open a tmp file for writing
	uid := uuid.New()
	path = fmt.Sprintf("/tmp/%s.%s", uid, ext)
	file, err := os.Create(path)
	if err != nil {
		return
	}
	defer file.Close()
	_, err = io.Copy(file, response.Body)
	return
}

func getRandomRedditMedia(b *keybasebot.Bot, sub string, sortby string, count int) (path, description string, err error) {
	submissions, err := getRedditSubmissions(b, sub, sortby, count)
	if err != nil {
		return
	}
	mediaSubs := filterMedia(submissions)
	// select a random post
	rand.Seed(time.Now().Unix())
	randSub := mediaSubs[rand.Intn(len(mediaSubs))]
	path, err = downloadRedditMedia(randSub)
	if err != nil {
		return
	}
	// generate the description
	description = fmt.Sprintf("image by /u/%s", randSub.Author)
	return
}