package notifications

import (
	"fmt"
	"io"
	"log/slog"
	"net/http"
	neturl "net/url"
	"os"
	"path/filepath"
	"time"

	"github.com/ayn2op/discordo/internal/config"
	"github.com/ayn2op/discordo/internal/consts"
	"github.com/diamondburned/arikawa/v3/discord"
	"github.com/diamondburned/arikawa/v3/gateway"
	"github.com/diamondburned/ningen/v3"
)

func Notify(state *ningen.State, message *gateway.MessageCreateEvent, cfg *config.Config) error {
	if !cfg.Notifications.Enabled || cfg.Status == discord.DoNotDisturbStatus {
		return nil
	}

	mentions := state.MessageMentions(&message.Message)
	if mentions == 0 {
		return nil
	}

	// Handle sent files
	content := message.Content
	if message.Content == "" && len(message.Attachments) > 0 {
		content = "Uploaded " + message.Attachments[0].Filename
	}

	if content == "" {
		return nil
	}

	title := message.Author.DisplayOrUsername()

	channel, err := state.Cabinet.Channel(message.ChannelID)
	if err != nil {
		return fmt.Errorf("failed to get channel from state: %w", err)
	}

	if channel.GuildID.IsValid() {
		guild, err := state.Cabinet.Guild(channel.GuildID)
		if err != nil {
			return fmt.Errorf("failed to get guild from state: %w", err)
		}

		if member := message.Member; member != nil && member.Nick != "" {
			title = member.Nick
		}

		title += " (#" + channel.Name + ", " + guild.Name + ")"
	}

	hash := message.Author.Avatar
	if hash == "" {
		hash = "default"
	}

	imagePath, err := getCachedProfileImage(hash, message.Author.AvatarURLWithType(discord.PNGImage))
	if err != nil {
		slog.Warn("failed to get profile image from cache for notification", "err", err, "hash", hash)
	}

	shouldChime := cfg.Notifications.Sound.Enabled && (!cfg.Notifications.Sound.OnlyOnPing || mentions.Has(ningen.MessageMentions|ningen.MessageNotifies))
	if err := sendDesktopNotification(title, content, imagePath, shouldChime, cfg.Notifications.Duration); err != nil {
		return err
	}

	return nil
}

var avatarHTTPClient = &http.Client{Timeout: 10 * time.Second}

func getCachedProfileImage(avatarHash discord.Hash, url string) (string, error) {
	dir := filepath.Join(consts.CacheDir(), "avatars")
	if err := os.MkdirAll(dir, 0700); err != nil {
		return "", err
	}

	safeHash := filepath.Base(string(avatarHash))
	path := filepath.Join(dir, safeHash+".png")
	if _, err := os.Stat(path); err == nil {
		return path, nil
	}

	parsed, err := neturl.Parse(url)
	if err != nil || parsed.Scheme != "https" {
		return "", fmt.Errorf("refusing non-HTTPS avatar URL")
	}

	resp, err := avatarHTTPClient.Get(url)
	if err != nil {
		return "", err
	}
	defer resp.Body.Close()

	if resp.StatusCode != http.StatusOK {
		return "", fmt.Errorf("unexpected status %d fetching avatar", resp.StatusCode)
	}

	file, err := os.OpenFile(path, os.O_CREATE|os.O_WRONLY|os.O_TRUNC, 0600)
	if err != nil {
		return "", err
	}
	defer file.Close()

	if _, err := io.Copy(file, io.LimitReader(resp.Body, 10*1024*1024)); err != nil {
		return "", err
	}

	return path, nil
}