feat(app): add internal components batch 4

internal/app/helpers.go

@@ -0,0 +1,142 @@
+package app
+
+import (
+	"crypto/sha256"
+	"encoding/hex"
+	"encoding/json"
+	"errors"
+	"fmt"
+	"net/url"
+	"os"
+	"path/filepath"
+	"regexp"
+	"strconv"
+	"strings"
+)
+
+var (
+	badNameChars = regexp.MustCompile(`[\\/\?%\*:|"<>\x00-\x1f]+`)
+	spaceChars   = regexp.MustCompile(`\s+`)
+	rePublicURL  = regexp.MustCompile(`(?i)(?:https?|socks5h?)://[^\s"'<>]+`)
+)
+
+func publicError(err error) error {
+	if err == nil {
+		return nil
+	}
+	return errors.New(redactErrorString(err.Error()))
+}
+
+func redactErrorString(s string) string {
+	return rePublicURL.ReplaceAllStringFunc(s, func(raw string) string {
+		u, err := url.Parse(raw)
+		if err != nil {
+			return "[无效 URL 已隐藏]"
+		}
+		if u.Host == "" {
+			return raw
+		}
+		if u.User != nil {
+			u.User = url.User("redacted")
+		}
+		if u.RawQuery != "" {
+			u.RawQuery = "[redacted]"
+		}
+		if u.Fragment != "" {
+			u.Fragment = "redacted"
+		}
+		return u.String()
+	})
+}
+
+func saveFailures(outputDir string, results []Result) error {
+	var failed []Result
+	for _, r := range results {
+		if !r.OK {
+			failed = append(failed, r)
+		}
+	}
+	if len(failed) == 0 {
+		return nil
+	}
+	b, err := json.MarshalIndent(failed, "", "  ")
+	if err != nil {
+		return err
+	}
+	return os.WriteFile(filepath.Join(outputDir, "failed.json"), b, 0o644)
+}
+
+func existingGood(path string, skipBytes int64) (bool, int64) {
+	st, err := os.Stat(path)
+	if err != nil || st.IsDir() {
+		return false, 0
+	}
+	return st.Size() >= skipBytes, st.Size()
+}
+
+func safeFilename(name string) string {
+	name = strings.TrimSpace(name)
+	name = badNameChars.ReplaceAllString(name, "_")
+	name = strings.ReplaceAll(name, "..", "_")
+	name = spaceChars.ReplaceAllString(name, " ")
+	name = strings.Trim(name, " ._")
+	if name == "" {
+		return "未命名"
+	}
+	upper := strings.ToUpper(name)
+	reserved := map[string]bool{"CON": true, "PRN": true, "AUX": true, "NUL": true, "COM1": true, "COM2": true, "COM3": true, "COM4": true, "COM5": true, "COM6": true, "COM7": true, "COM8": true, "COM9": true, "LPT1": true, "LPT2": true, "LPT3": true, "LPT4": true, "LPT5": true, "LPT6": true, "LPT7": true, "LPT8": true, "LPT9": true}
+	if reserved[strings.SplitN(upper, ".", 2)[0]] {
+		name = "_" + name
+	}
+	runes := []rune(name)
+	if len(runes) > 100 {
+		name = string(runes[:100])
+	}
+	return name
+}
+
+func safeJoin(base string, elem ...string) (string, error) {
+	cleanBase, err := filepath.Abs(base)
+	if err != nil {
+		return "", err
+	}
+	parts := []string{cleanBase}
+	for _, e := range elem {
+		parts = append(parts, safeFilename(e))
+	}
+	joined := filepath.Join(parts...)
+	abs, err := filepath.Abs(joined)
+	if err != nil {
+		return "", err
+	}
+	rel, err := filepath.Rel(cleanBase, abs)
+	if err != nil {
+		return "", err
+	}
+	if rel == ".." || strings.HasPrefix(rel, ".."+string(filepath.Separator)) || filepath.IsAbs(rel) {
+		return "", fmt.Errorf("unsafe path outside output dir: %s", abs)
+	}
+	return abs, nil
+}
+
+func padEpisode(ep string) string {
+	ep = strings.TrimSpace(ep)
+	if n, err := strconv.Atoi(ep); err == nil {
+		return fmt.Sprintf("%03d", n)
+	}
+	return safeFilename(ep)
+}
+
+func hashShort(s string) string {
+	h := sha256.Sum256([]byte(s))
+	return hex.EncodeToString(h[:])[:12]
+}
+
+func truncate(s string, n int) string {
+	s = strings.TrimSpace(s)
+	r := []rune(s)
+	if len(r) <= n {
+		return s
+	}
+	return string(r[:n]) + "..."
+}