ntfy-discord/internal/discord/webhook.go

package discord

import (
	"bytes"
	"context"
	"encoding/json"
	"fmt"
	"io"
	"log/slog"
	"net/http"
	"strconv"
	"strings"
	"time"

	"git.daviestechlabs.io/daviestechlabs/ntfy-discord/internal/ntfy"
)

// Priority to Discord embed color mapping
var priorityColors = map[int]int{
	5: 15158332, // Red - Max/Urgent
	4: 15105570, // Orange - High
	3: 3066993,  // Blue - Default
	2: 9807270,  // Gray - Low
	1: 12370112, // Light Gray - Min
}

// Tag to emoji mapping
var tagEmojis = map[string]string{
	"white_check_mark": "✅",
	"heavy_check_mark": "✅",
	"check":            "✅",
	"x":                "❌",
	"skull":            "❌",
	"warning":          "⚠️",
	"rotating_light":   "🚨",
	"rocket":           "🚀",
	"package":          "📦",
	"tada":             "🎉",
	"fire":             "🔥",
	"bug":              "🐛",
	"wrench":           "🔧",
	"gear":             "⚙️",
	"lock":             "🔒",
	"key":              "🔑",
	"bell":             "🔔",
	"mega":             "📢",
	"eyes":             "👀",
	"sos":              "🆘",
	"no_entry":         "⛔",
	"construction":     "🚧",
}

// Embed represents a Discord embed
type Embed struct {
	Title       string  `json:"title,omitempty"`
	Description string  `json:"description,omitempty"`
	Color       int     `json:"color,omitempty"`
	Fields      []Field `json:"fields,omitempty"`
	Timestamp   string  `json:"timestamp,omitempty"`
	Footer      *Footer `json:"footer,omitempty"`
}

// Field represents a Discord embed field
type Field struct {
	Name   string `json:"name"`
	Value  string `json:"value"`
	Inline bool   `json:"inline,omitempty"`
}

// Footer represents a Discord embed footer
type Footer struct {
	Text string `json:"text"`
}

// WebhookPayload is the Discord webhook request body
type WebhookPayload struct {
	Embeds []Embed `json:"embeds"`
}

// Client sends messages to Discord webhooks
type Client struct {
	httpClient *http.Client
}

// NewClient creates a new Discord webhook client
func NewClient() *Client {
	return &Client{
		httpClient: &http.Client{
			Timeout: 30 * time.Second,
		},
	}
}

// Send converts an ntfy message to Discord format and sends it
func (c *Client) Send(ctx context.Context, webhookURL string, msg ntfy.Message) error {
	if webhookURL == "" {
		return fmt.Errorf("no webhook URL configured")
	}

	embed := c.buildEmbed(msg)
	payload := WebhookPayload{
		Embeds: []Embed{embed},
	}

	body, err := json.Marshal(payload)
	if err != nil {
		return fmt.Errorf("marshal payload: %w", err)
	}

	req, err := http.NewRequestWithContext(ctx, http.MethodPost, webhookURL, bytes.NewReader(body))
	if err != nil {
		return fmt.Errorf("create request: %w", err)
	}
	req.Header.Set("Content-Type", "application/json")

	resp, err := c.httpClient.Do(req)
	if err != nil {
		return fmt.Errorf("send request: %w", err)
	}
	defer func() { _ = resp.Body.Close() }()

	// Handle rate limiting
	if resp.StatusCode == http.StatusTooManyRequests {
		retryAfter := resp.Header.Get("Retry-After")
		if retryAfter != "" {
			if seconds, err := strconv.Atoi(retryAfter); err == nil {
				slog.Warn("Discord rate limited", "retry_after", seconds)
				time.Sleep(time.Duration(seconds) * time.Second)
				return c.Send(ctx, webhookURL, msg) // Retry
			}
		}
		return fmt.Errorf("rate limited")
	}

	if resp.StatusCode < 200 || resp.StatusCode >= 300 {
		respBody, _ := io.ReadAll(io.LimitReader(resp.Body, 1024))
		return fmt.Errorf("unexpected status %d: %s", resp.StatusCode, string(respBody))
	}

	return nil
}

func (c *Client) buildEmbed(msg ntfy.Message) Embed {
	// Get color from priority
	color := priorityColors[3] // Default
	if msg.Priority >= 1 && msg.Priority <= 5 {
		color = priorityColors[msg.Priority]
	}

	// Build title with emoji prefix
	title := msg.Title
	if title == "" {
		title = msg.Topic
	}
	emoji := c.extractEmoji(msg.Tags)
	if emoji != "" {
		title = emoji + " " + title
	}

	// Build timestamp
	timestamp := ""
	if msg.Time > 0 {
		timestamp = time.Unix(msg.Time, 0).UTC().Format(time.RFC3339)
	}

	embed := Embed{
		Title:       title,
		Description: msg.Message,
		Color:       color,
		Timestamp:   timestamp,
		Footer:      &Footer{Text: "ntfy"},
	}

	// Add topic as field
	if msg.Topic != "" {
		embed.Fields = append(embed.Fields, Field{
			Name:   "Topic",
			Value:  msg.Topic,
			Inline: true,
		})
	}

	// Add click URL if present
	if msg.Click != "" {
		embed.Fields = append(embed.Fields, Field{
			Name:   "Link",
			Value:  msg.Click,
			Inline: false,
		})
	}

	return embed
}

func (c *Client) extractEmoji(tags []string) string {
	for _, tag := range tags {
		tag = strings.ToLower(tag)
		if emoji, ok := tagEmojis[tag]; ok {
			return emoji
		}
	}
	return ""
}