refactor: reorganize project structure following go standards

api/playback/service_ranking.go

@@ -0,0 +1,184 @@
+package playback
+
+import (
+	"bytes"
+	"errors"
+	"sort"
+	"strconv"
+	"strings"
+)
+
+func rankSources(sources []StreamSource, quality string) ([]sourceScore, error) {
+	filtered := make([]StreamSource, 0, len(sources))
+	seen := make(map[string]struct{})
+
+	for _, source := range sources {
+		if source.URL == "" {
+			continue
+		}
+		if _, exists := seen[source.URL]; exists {
+			continue
+		}
+		seen[source.URL] = struct{}{}
+		filtered = append(filtered, source)
+	}
+
+	if len(filtered) == 0 {
+		return nil, errors.New("no playable sources available")
+	}
+
+	targetQuality := normalizeQuality(quality)
+	scored := make([]sourceScore, 0, len(filtered))
+	for _, source := range filtered {
+		typeScore := lookupPriority(sourceTypePriority, source.Type, 200)
+		providerScore := lookupPriority(providerPriority, source.Provider, 60)
+		qualityScore := sourceQualityPriority(source.Quality, targetQuality)
+		refererScore := 0
+		if source.Referer != "" {
+			refererScore = 20
+		}
+
+		total := typeScore + providerScore + qualityScore + refererScore
+		scored = append(scored, sourceScore{
+			source:        source,
+			total:         total,
+			typeScore:     typeScore,
+			providerScore: providerScore,
+			qualityScore:  qualityScore,
+			refererScore:  refererScore,
+		})
+	}
+
+	sort.SliceStable(scored, func(i int, j int) bool {
+		return scored[i].total > scored[j].total
+	})
+
+	return scored, nil
+}
+
+func normalizeQuality(quality string) string {
+	lower := strings.ToLower(strings.TrimSpace(quality))
+	if lower == "" {
+		return "best"
+	}
+
+	return lower
+}
+
+var sourceTypePriority = map[string]int{
+	"mp4":     500,
+	"m3u8":    450,
+	"unknown": 300,
+	"embed":   100,
+}
+
+var providerPriority = map[string]int{
+	"s-mp4":   120,
+	"default": 115,
+	"luf-mp4": 110,
+	"vid-mp4": 105,
+	"yt-mp4":  100,
+	"mp4":     95,
+	"uv-mp4":  90,
+	"hls":     80,
+	"sw":      40,
+	"ok":      35,
+	"ss-hls":  30,
+}
+
+var sourceQualityDefaults = map[string]int{
+	"auto": 240,
+}
+
+func lookupPriority(m map[string]int, key string, fallback int) int {
+	if p, ok := m[strings.ToLower(key)]; ok {
+		return p
+	}
+	return fallback
+}
+
+func sourceQualityPriority(sourceQuality string, targetQuality string) int {
+	qualityValue := parseQualityValue(sourceQuality)
+
+	switch targetQuality {
+	case "best":
+		return qualityValue
+	case "worst":
+		return -qualityValue
+	default:
+		if qualityMatches(sourceQuality, targetQuality) {
+			return 2000 + qualityValue
+		}
+
+		return -300 + qualityValue
+	}
+}
+
+func qualityMatches(sourceQuality string, targetQuality string) bool {
+	sourceLower := strings.ToLower(sourceQuality)
+	targetLower := strings.ToLower(targetQuality)
+
+	if sourceLower == "" {
+		return false
+	}
+
+	if strings.Contains(sourceLower, targetLower) {
+		return true
+	}
+
+	return extractDigits(sourceLower) == extractDigits(targetLower)
+}
+
+func parseQualityValue(rawQuality string) int {
+	lower := strings.ToLower(rawQuality)
+	if lower == "auto" {
+		return 240
+	}
+
+	digits := extractDigits(lower)
+	if digits == "" {
+		return 0
+	}
+
+	value, err := strconv.Atoi(digits)
+	if err != nil {
+		return 0
+	}
+	return value
+}
+
+func extractDigits(value string) string {
+	var digits []byte
+	for _, char := range value {
+		if char >= '0' && char <= '9' {
+			digits = append(digits, byte(char))
+		} else if len(digits) > 0 {
+			break
+		}
+	}
+	return string(digits)
+}
+
+func normalizeSourceTypeFromProbe(source StreamSource, contentType string) StreamSource {
+	lower := strings.ToLower(contentType)
+	switch {
+	case strings.Contains(lower, "video/mp4"):
+		source.Type = "mp4"
+	case strings.Contains(lower, "mpegurl"):
+		source.Type = "m3u8"
+	}
+	return source
+}
+
+func isLikelyMP4(payload []byte) bool {
+	if len(payload) < 12 {
+		return false
+	}
+
+	return bytes.Equal(payload[4:8], []byte("ftyp"))
+}
+
+func isLikelyM3U8(payload []byte) bool {
+	trimmed := strings.TrimSpace(string(payload))
+	return strings.HasPrefix(trimmed, "#EXTM3U")
+}