package main

import (
	"bytes"
	"flag"
	"fmt"
	"io/ioutil"
	"log"
	"net/http"
	"strings"
	"time"

	"github.com/turnage/graw/reddit"
	"github.com/turnage/graw/streams"
)

// UA is the user agent for Reddit
const UA = `NixOS:tulpa.dev/cadey/snoo2nebby:v0.1.0 (by /u/shadowh511)`

var (
	webhookFile = flag.String("webhook-file", "./var/webhook.txt", "where the Discord webhook file is located")
	subreddit   = flag.String("subreddit", "tulpas", "the subreddit to monitor")
	pokeFreq    = flag.Duration("poke-frequency", 5*time.Minute, "how often the bot should poke the feed")
	allowNSFW   = flag.Bool("allow-nsfw", false, "proxy NSFW posts?")
)

func clampLen(data string) string {
	if len(data) < 1800 {
		return data
	}

	var sb strings.Builder
	sb.WriteString(data[0:1800])
	sb.WriteString("\n\n[Post truncated for length]")

	return sb.String()
}

func main() {
	flag.Parse()

	script, err := reddit.NewScript(UA, *pokeFreq)
	if err != nil {
		log.Fatal(err)
	}

	whSlc, err := ioutil.ReadFile(*webhookFile)
	if err != nil {
		log.Fatal(err)
	}
	whURL := string(bytes.TrimSpace(whSlc))

	kill := make(chan bool)
	errs := make(chan error)

	stream, err := streams.Subreddits(script, kill, errs, *subreddit)
	if err != nil {
		log.Fatal(err)
	}

	go func(errs chan error) {
		for err := range errs {
			log.Printf("%v", err)
		}
	}(errs)

	log.Printf("listening for new posts on /r/%s", *subreddit)

	for post := range stream {
		log.Printf("got new post: by /u/%s: %q %s, NSFW: %v", post.Author, post.URL, post.Title, post.NSFW)

		if post.NSFW && !*allowNSFW {
			continue
		}

		wh := Webhook{
			Embeds: []Embed{
				{
					Title:       post.Title,
					URL:         post.URL,
					Description: clampLen(post.SelfText),
					Footer: EmbedFooter{
						Text: "by /u/" + post.Author,
					},
				},
			},
		}

		req := Send(whURL, wh)
		req.Header.Set("User-Agent", UA)
		resp, err := http.DefaultClient.Do(req)
		if err != nil {
			errs <- fmt.Errorf("can't send webhook: %w", err)
			continue
		}
		err = Validate(resp)
		if err != nil {
			errs <- fmt.Errorf("can't validate response: %w", err)
			continue
		}
	}
}