package main

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

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

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

var (
	agentFile   = flag.String("agent-file", "./var/agent.yml", "the path to the bot's reddit agent config")
	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()
}

type postReplicatingBot struct {
	whURL string
	bot   reddit.Bot
}

func (p *postReplicatingBot) Post(post *reddit.Post) error {
	log.Printf("got new post: by /u/%s: %q %s, NSFW: %v", post.Author, post.URL, post.Title, post.NSFW)

	if post.NSFW && !*allowNSFW {
		return nil
	}

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

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

	return nil
}

func main() {
	flag.Parse()

	script, err := reddit.NewBotFromAgentFile(*agentFile, 5*time.Minute)

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

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

	if _, wait, err := graw.Run(&postReplicatingBot{whURL, script}, script, graw.Config{Subreddits: []string{*subreddit}}); err != nil {
		log.Fatalf("can't connect to reddit: %v", err)
	} else {
		log.Fatalf("graw run failed: %v", wait())
	}
}