save first version

internal/transcript/generator.go

@@ -0,0 +1,147 @@
+package transcript
+
+import (
+	"bytes"
+	"fmt"
+	"html/template"
+	"log/slog"
+	"os"
+	"path/filepath"
+	"strings"
+	"time"
+
+	"github.com/bwmarrin/discordgo"
+	"github.com/leolionad58/ticketbot/internal/db"
+)
+
+const maxUploadSize = 25 * 1024 * 1024 // 25MB
+
+type Message struct {
+	AuthorName    string
+	AuthorAvatar  string
+	AuthorInitial string
+	Content       template.HTML
+	Timestamp     string
+	Attachments   []Attachment
+}
+
+type Attachment struct {
+	Name string
+	URL  string
+}
+
+type Generator struct {
+	OutputDir string
+	Session   *discordgo.Session
+}
+
+func NewGenerator(outputDir string, s *discordgo.Session) *Generator {
+	return &Generator{OutputDir: outputDir, Session: s}
+}
+
+// Generate fetches all messages from the ticket channel and writes the HTML transcript.
+// Returns the output file path.
+func (g *Generator) Generate(ticket *db.Ticket) (string, error) {
+	messages, err := g.fetchAll(ticket.ChannelID)
+	if err != nil {
+		return "", fmt.Errorf("fetch messages: %w", err)
+	}
+
+	rendered := make([]Message, 0, len(messages))
+	for _, m := range messages {
+		rendered = append(rendered, renderMessage(m))
+	}
+
+	tmpl, err := template.New("transcript").Parse(HTMLTemplate)
+	if err != nil {
+		return "", fmt.Errorf("parse template: %w", err)
+	}
+
+	data := struct {
+		Ticket    *db.Ticket
+		Messages  []Message
+		Generated string
+	}{
+		Ticket:    ticket,
+		Messages:  rendered,
+		Generated: time.Now().UTC().Format("02/01/2006 à 15:04 UTC"),
+	}
+
+	var buf bytes.Buffer
+	if err := tmpl.Execute(&buf, data); err != nil {
+		return "", fmt.Errorf("render template: %w", err)
+	}
+
+	if err := os.MkdirAll(g.OutputDir, 0755); err != nil {
+		return "", fmt.Errorf("create output dir: %w", err)
+	}
+
+	outPath := filepath.Join(g.OutputDir,
+		fmt.Sprintf("%s-%04d-%s.html", ticket.Type, ticket.TicketNumber, ticket.ChannelID))
+
+	if buf.Len() > maxUploadSize {
+		slog.Warn("transcript exceeds 25MB, saving locally only", "path", outPath, "size_mb", buf.Len()/1024/1024)
+	}
+
+	if err := os.WriteFile(outPath, buf.Bytes(), 0644); err != nil {
+		return "", fmt.Errorf("write transcript: %w", err)
+	}
+	return outPath, nil
+}
+
+func (g *Generator) fetchAll(channelID string) ([]*discordgo.Message, error) {
+	var all []*discordgo.Message
+	var before string
+	for {
+		batch, err := g.Session.ChannelMessages(channelID, 100, before, "", "")
+		if err != nil {
+			return nil, err
+		}
+		all = append(all, batch...)
+		if len(batch) < 100 {
+			break
+		}
+		before = batch[len(batch)-1].ID
+	}
+	// Reverse to chronological order
+	for i, j := 0, len(all)-1; i < j; i, j = i+1, j-1 {
+		all[i], all[j] = all[j], all[i]
+	}
+	return all, nil
+}
+
+func renderMessage(m *discordgo.Message) Message {
+	name := m.Author.Username
+	avatar := m.Author.AvatarURL("64")
+	initial := "?"
+	if len(name) > 0 {
+		initial = strings.ToUpper(string([]rune(name)[0]))
+	}
+
+	// Escape all user content — XSS protection
+	content := template.HTMLEscapeString(m.Content)
+	// Preserve newlines as <br>
+	contentHTML := template.HTML(strings.ReplaceAll(content, "\n", "<br>"))
+
+	ts := ""
+	if !m.Timestamp.IsZero() {
+		ts = m.Timestamp.UTC().Format("02/01/2006 15:04:05")
+	}
+
+	var attachments []Attachment
+	for _, a := range m.Attachments {
+		attachments = append(attachments, Attachment{
+			Name: template.HTMLEscapeString(a.Filename),
+			URL:  a.URL,
+		})
+	}
+
+	return Message{
+		AuthorName:    template.HTMLEscapeString(name),
+		AuthorAvatar:  avatar,
+		AuthorInitial: initial,
+		Content:       contentHTML,
+		Timestamp:     ts,
+		Attachments:   attachments,
+	}
+}