Reimplement FindMatches

shazam/shazam.go

@@ -3,6 +3,7 @@ package shazam
 import (
 	"fmt"
 	"math"
+	"song-recognition/models"
 	"song-recognition/utils"
 	"sort"
 	"time"
@@ -17,7 +18,6 @@ type Match struct {
 	Score      float64
 }
 
-// FindMatches processes the audio samples and finds matches in the database
 func FindMatches(audioSamples []float64, audioDuration float64, sampleRate int) ([]Match, time.Duration, error) {
 	startTime := time.Now()
 	logger := utils.GetLogger()
@@ -30,9 +30,11 @@ func FindMatches(audioSamples []float64, audioDuration float64, sampleRate int)
 	peaks := ExtractPeaks(spectrogram, audioDuration)
 	fingerprints := Fingerprint(peaks, utils.GenerateUniqueID())
 
+	var sampleCouples []models.Couple
 	addresses := make([]uint32, 0, len(fingerprints))
 	for address := range fingerprints {
 		addresses = append(addresses, address)
+		sampleCouples = append(sampleCouples, fingerprints[address])
 	}
 
 	db, err := utils.NewDbClient()
@@ -41,61 +43,103 @@ func FindMatches(audioSamples []float64, audioDuration float64, sampleRate int)
 	}
 	defer db.Close()
 
-	m, err := db.GetCouples(addresses)
+	couplesMap, err := db.GetCouples(addresses)
 	if err != nil {
 		return nil, time.Since(startTime), err
 	}
 
-	matches := map[uint32][][2]uint32{} // songID -> [(sampleTime, dbTime)]
-	timestamps := map[uint32]uint32{}
-
-	for address, couples := range m {
+	// Count occurrences of each couple to derive potential target zones
+	coupleCounts := make(map[uint32]map[uint32]int)
+	for _, couples := range couplesMap {
 		for _, couple := range couples {
-			matches[couple.SongID] = append(matches[couple.SongID], [2]uint32{fingerprints[address].AnchorTimeMs, couple.AnchorTimeMs})
-			timestamps[couple.SongID] = couple.AnchorTimeMs
+			key := (couple.SongID << 32) | uint32(couple.AnchorTimeMs)
+			if _, exists := coupleCounts[couple.SongID]; !exists {
+				coupleCounts[couple.SongID] = make(map[uint32]int)
+			}
+			coupleCounts[couple.SongID][key]++
 		}
 	}
 
-	scores := analyzeRelativeTiming(matches)
-
-	var matchList []Match
-	for songID, points := range scores {
-		song, songExists, err := db.GetSongByID(songID)
-		if !songExists {
-			logger.Info(fmt.Sprintf("song with ID (%v) doesn't exist", songID))
-			continue
+	// Filter target zones with targets (couples) meeting or exceeding the threshold
+	threshold := 4
+	filteredCouples := make(map[uint32][]models.Couple)
+	for songID, counts := range coupleCounts {
+		for key, count := range counts {
+			if count >= threshold {
+				filteredCouples[songID] = append(filteredCouples[songID], models.Couple{
+					AnchorTimeMs: key & 0xFFFFFFFF,
+					SongID:       songID,
+				})
+			}
 		}
+	}
+
+	// Score matches by calculating mean absolute difference
+	var matches []Match
+	for songID, songCouples := range filteredCouples {
+		song, songExists, err := db.GetSongByID(songID)
 		if err != nil {
 			logger.Info(fmt.Sprintf("failed to get song by ID (%v): %v", songID, err))
 			continue
 		}
+		if !songExists {
+			logger.Info(fmt.Sprintf("song with ID (%v) doesn't exist", songID))
+			continue
+		}
 
-		match := Match{songID, song.Title, song.Artist, song.YouTubeID, timestamps[songID], points}
-		matchList = append(matchList, match)
+		m_a_d := meanAbsoluteDifference(songCouples, sampleCouples)
+
+		tstamp := songCouples[len(songCouples)-1].AnchorTimeMs
+		match := Match{songID, song.Title, song.Artist, song.YouTubeID, tstamp, m_a_d}
+		matches = append(matches, match)
 	}
 
-	sort.Slice(matchList, func(i, j int) bool {
-		return matchList[i].Score > matchList[j].Score
+	sort.Slice(matches, func(i, j int) bool {
+		return matches[i].Score > matches[j].Score
 	})
 
-	return matchList, time.Since(startTime), nil
+	// TODO: hanld case when there's no match for cmdHandlers
+
+	return matches, time.Since(startTime), nil
 }
 
-// AnalyzeRelativeTiming checks for consistent relative timing and returns a score
-func analyzeRelativeTiming(matches map[uint32][][2]uint32) map[uint32]float64 {
-	scores := make(map[uint32]float64)
-	for songID, times := range matches {
-		count := 0
-		for i := 0; i < len(times); i++ {
-			for j := i + 1; j < len(times); j++ {
-				sampleDiff := math.Abs(float64(times[i][0] - times[j][0]))
-				dbDiff := math.Abs(float64(times[i][1] - times[j][1]))
-				if math.Abs(sampleDiff-dbDiff) < 100 { // Allow some tolerance
-					count++
-				}
-			}
-		}
-		scores[songID] = float64(count)
+func meanAbsoluteDifference(A, B []models.Couple) float64 {
+	minLen := len(A)
+	if len(B) < minLen {
+		minLen = len(B)
 	}
-	return scores
+
+	var sumDiff float64
+	for i := 0; i < minLen; i++ {
+		diff := math.Abs(float64(A[i].AnchorTimeMs - B[i].AnchorTimeMs))
+		sumDiff += diff
+	}
+
+	meanAbsDiff := sumDiff / float64(minLen)
+	return meanAbsDiff
+}
+
+// Function to calculate Dynamic Time Warping distance
+func dynamicTimeWarping(A, B []models.Couple) float64 {
+	lenA := len(A)
+	lenB := len(B)
+
+	// Create a 2D array to store DTW distances
+	dtw := make([][]float64, lenA+1)
+	for i := range dtw {
+		dtw[i] = make([]float64, lenB+1)
+		for j := range dtw[i] {
+			dtw[i][j] = math.Inf(1)
+		}
+	}
+	dtw[0][0] = 0
+
+	for i := 1; i <= lenA; i++ {
+		for j := 1; j <= lenB; j++ {
+			cost := math.Abs(float64(A[i-1].AnchorTimeMs - B[j-1].AnchorTimeMs))
+			dtw[i][j] = cost + math.Min(math.Min(dtw[i-1][j], dtw[i][j-1]), dtw[i-1][j-1])
+		}
+	}
+
+	return dtw[lenA][lenB]
 }