package main

import (
	"bufio"
	"fmt"
	"net/http"
	"net/url"
	"os"
	"os/exec"
	"sort"
	"strings"
	"time"

	"golang.org/x/sys/unix"
)

func main() {
	if len(os.Args) != 2 {
		fmt.Fprintf(os.Stderr, "Usage: %s <submission id/url>\n", os.Args[0])
		os.Exit(1)
	}
	submissionUrl, err := url.Parse(os.Args[1])
	if err != nil {
		fmt.Fprintf(os.Stderr, "Error when parsing submission url: %s\n", err)
		os.Exit(1)
	}
	submissionId := os.Args[1]
	if submissionUrl.Hostname() == "redd.it" {
		submissionId = submissionUrl.EscapedPath()[1:]
	} else if submissionUrl.Hostname() != "" {
		split := strings.SplitN(submissionUrl.EscapedPath(), "/", 6)
		if len(split) < 5 {
			fmt.Fprintln(os.Stderr, "URL passed does not have enough path seperators")
			os.Exit(1)
		}
		submissionId = split[4]
	}
	if submissionId == "" {
		fmt.Fprintln(os.Stderr, "Submission ID is empty")
		os.Exit(1)
	}
	client := &http.Client{
		Timeout: time.Duration(30 * time.Second),
	}
	err = LoadConfigAndData()
	if err != nil {
		fmt.Fprintf(os.Stderr, "Failed to load config and data: %s\n", err)
		os.Exit(1)
	}
	token, err := GetToken(client)
	if err != nil {
		fmt.Fprintf(os.Stderr, "Failed to get token: %s\n", err)
		os.Exit(1)
	}
	submission, err := GetSubmission(client, token, submissionId)
	if err != nil {
		fmt.Fprintf(os.Stderr, "Failed to get submission: %s\n", err)
		os.Exit(1)
	}
	filename := strings.ReplaceAll(submission.Title, "/", "_") + "-" + submissionId
	if filename[0] == '.' {
		filename = "_" + filename[1:]
	}
	files, err := os.ReadDir(".")
	if err != nil {
		fmt.Fprintf(os.Stderr, "Failed to list files: %s\n", err)
		os.Exit(1)
	}
	stdin := bufio.NewReader(os.Stdin)
	for _, i := range files {
		if strings.HasPrefix(i.Name(), filename) {
			fmt.Printf("A file that starts with %s exists (%s), potentially overwrite (y/N)? ", filename, i.Name())
			b, err := stdin.ReadByte()
			if err != nil {
				fmt.Fprintf(os.Stderr, "Error when reading stdin: %s\n", err)
				os.Exit(1)
			}
			if b != 'y' && b != 'Y' {
				fmt.Println("Not overwriting")
				os.Exit(1)
			}
			break
		}
	}
	if submission.CrosspostParent != "" && len(submission.CrosspostParentList) > 0 {
		submission, err = GetSubmission(client, token, submission.CrosspostParent[3:])
		if err != nil {
			fmt.Fprintf(os.Stderr, "Failed to get original submission: %s\n", err)
			os.Exit(1)
		}
	}
	if submission.IsSelf {
		fmt.Fprintln(os.Stderr, "Cannot download selfposts")
		os.Exit(1)
	}
	urls := make([]string, 1)
	urls[0] = submission.Url
	if submission.IsVideo {
		ffmpegPath, err := exec.LookPath("ffmpeg")
		if err != nil {
			fmt.Fprintf(os.Stderr, "Failed to find ffmpeg: %s\n", err)
			os.Exit(1)
		}
		ffmpegUrl := submission.SecureMedia.RedditVideo.HlsUrl
		if ffmpegUrl == "" {
			ffmpegUrl = submission.SecureMedia.RedditVideo.DashUrl
		}
		if ffmpegUrl != "" {
			client.CloseIdleConnections()
			err = unix.Exec(ffmpegPath, []string{"ffmpeg", "-nostdin", "-i", ffmpegUrl, "-c", "copy", "--", filename + ".mp4"}, os.Environ())
			fmt.Fprintf(os.Stderr, "Failed to exec as ffmpeg: %s\n", err)
			os.Exit(1)
		}
		fallbackUrl := submission.SecureMedia.RedditVideo.FallbackUrl
		if fallbackUrl != "" {
			urls[0] = fallbackUrl
		}
	} else if submission.IsGallery {
		var galleryKeys []string
		if submission.GalleryData != nil {
			sort.Sort(submission.GalleryData)
			for _, i := range submission.GalleryData.Items {
				galleryKeys = append(galleryKeys, i.MediaId)
			}
		} else {
			for i, _ := range submission.MediaMetadata {
				galleryKeys = append(galleryKeys, i)
			}
		}
		urls = nil
		for _, i := range galleryKeys {
			mediaMetadataItem := submission.MediaMetadata[i]
			if mediaMetadataItem.Status != "valid" {
				continue
			}
			if mediaMetadataItem.S.U != "" {
				urls = append(urls, mediaMetadataItem.S.U)
			} else if mediaMetadataItem.S.Mp4 != "" {
				urls = append(urls, mediaMetadataItem.S.Mp4)
			} else if mediaMetadataItem.S.Gif != "" {
				urls = append(urls, mediaMetadataItem.S.Gif)
			}
		}
	}
	fmt.Println(urls)
	i, err := InteractivelyAskIndex(stdin, urls)
	if err != nil {
		fmt.Fprintf(os.Stderr, "Failed to get index: %s\n", err)
		os.Exit(1)
	}
	url := urls[i]
	fmt.Println(url)
}