feat: initial implementation of uptodownbot

Telegram bot for downloading media from any site using yt-dlp.
Supports audio/video/both, quality selection, language picker,
container format selection, playlist pagination, progress updates,
per-user quotas, user preferences, download history, cancel at any step,
polling and webhook modes, proxy support, and SQLite persistence.

internal/dl/progress.go

@@ -0,0 +1,78 @@
+package dl
+
+import (
+	"bufio"
+	"io"
+	"regexp"
+	"strconv"
+	"strings"
+
+	"uptodownBot/internal/domain"
+)
+
+var progressRE = regexp.MustCompile(`\[\w+\]\s+([\d.]+)%\s+of\s+~?([\d.]+)(\w+)`)
+
+type progressUpdate struct {
+	pct   float64
+	speed string
+	eta   string
+}
+
+// parseProgressLine parses a single yt-dlp stderr progress line.
+// Returns nil if the line doesn't contain progress info.
+func parseProgressLine(line string) *progressUpdate {
+	line = strings.TrimSpace(line)
+	if line == "" || !strings.HasPrefix(line, "[download]") {
+		return nil
+	}
+	// Try to extract the simple percentage from the default format:
+	// [download] 45.2% of 123.45MiB at 2.34MiB/s ETA 00:45
+	m := progressRE.FindStringSubmatch(line)
+	if m == nil {
+		return nil
+	}
+	pct, err := strconv.ParseFloat(m[1], 64)
+	if err != nil {
+		return nil
+	}
+
+	u := &progressUpdate{pct: pct}
+
+	// Extract speed and ETA from remaining parts
+	rest := line
+	if idx := strings.Index(rest, "%"); idx >= 0 {
+		rest = rest[idx+1:]
+	}
+	// Look for "at <speed>"
+	if atIdx := strings.Index(rest, " at "); atIdx >= 0 {
+		afterAt := rest[atIdx+4:]
+		if spaceIdx := strings.Index(afterAt, " "); spaceIdx >= 0 {
+			u.speed = strings.TrimSpace(afterAt[:spaceIdx])
+			rest = afterAt[spaceIdx:]
+		}
+	}
+	// Look for "ETA <duration>"
+	if etaIdx := strings.Index(rest, "ETA "); etaIdx >= 0 {
+		etaStr := strings.TrimSpace(rest[etaIdx+4:])
+		u.eta = etaStr
+	}
+
+	return u
+}
+
+// readProgress reads yt-dlp stderr and sends progress updates to the channel.
+func readProgress(stderr io.ReadCloser, updates chan<- *domain.DownloadJob, job *domain.DownloadJob) {
+	defer close(updates)
+	scanner := bufio.NewScanner(stderr)
+	for scanner.Scan() {
+		line := scanner.Text()
+		parsed := parseProgressLine(line)
+		if parsed == nil {
+			continue
+		}
+		job.Progress = parsed.pct
+		job.Speed = parsed.speed
+		job.ETA = parsed.eta
+		updates <- job
+	}
+}