add nextLogs and prevLogs suggestions to log.

services/logs.go

@@ -783,3 +783,102 @@ func (s *LogService) makeCharacterMap(characters []*models.Character) map[string
 
 	return characterMap
 }
+
+func (s *LogService) NextLogs(ctx context.Context, log *models.Log) ([]*models.LogSuggestion, error) {
+	minDate := log.Date.Add(time.Millisecond)
+	logs, err := s.logs.List(ctx, models.LogFilter{
+		MinDate: &minDate,
+	})
+	if err != nil {
+		return nil, err
+	}
+
+	sort.Slice(logs, func(i, j int) bool {
+		return logs[i].Date.Before(logs[j].Date)
+	})
+
+	return s.findSuggestions(ctx, log, logs)
+}
+
+func (s *LogService) PrevLogs(ctx context.Context, log *models.Log) ([]*models.LogSuggestion, error) {
+	logs, err := s.logs.List(ctx, models.LogFilter{
+		MaxDate: &log.Date,
+	})
+	if err != nil {
+		return nil, err
+	}
+
+	return s.findSuggestions(ctx, log, logs)
+}
+
+func (s *LogService) findSuggestions(ctx context.Context, log *models.Log, logs []*models.Log) ([]*models.LogSuggestion, error) {
+	characters, err := s.characterService.List(ctx, models.CharacterFilter{
+		IDs: log.CharacterIDs,
+	})
+	if err != nil {
+		return nil, err
+	}
+
+	charIntersect := func(l1, l2 *models.Log) []*models.Character {
+		results := make([]*models.Character, 0, len(l1.CharacterIDs))
+		for _, c1 := range characters {
+			for _, c2ID := range l2.CharacterIDs {
+				if c1.ID == c2ID {
+					results = append(results, c1)
+					break
+				}
+			}
+		}
+
+		return results
+	}
+	groupKey := func(characters []*models.Character) string {
+		if len(characters) == 0 {
+			return ""
+		} else if len(characters) == 1 {
+			return characters[0].ID
+		}
+
+		builder := strings.Builder{}
+		builder.WriteString(characters[0].ID)
+
+		for _, character := range characters {
+			builder.WriteRune(',')
+			builder.WriteString(character.ID)
+		}
+
+		return builder.String()
+	}
+
+	suggestions := make([]*models.LogSuggestion, 0, 16)
+	foundGroups := make(map[string]bool)
+	foundChannel := false
+
+	for _, log2 := range logs {
+		hasEvent := log.EventName != "" && log2.EventName == log.EventName
+		hasChannel := log.ChannelName == log2.ChannelName
+		characters := charIntersect(log, log2)
+		groupKey := groupKey(characters)
+
+		suggestion := &models.LogSuggestion{
+			Log:        log2,
+			Characters: characters,
+			HasChannel: hasChannel,
+			HasEvent:   hasEvent,
+		}
+
+		if hasChannel && foundChannel {
+			foundChannel = true
+			foundGroups[groupKey] = true
+			suggestions = append(suggestions, suggestion)
+		} else if hasEvent {
+			foundGroups[groupKey] = true
+			suggestions = append(suggestions, suggestion)
+		} else if len(suggestions) < 8 && !hasEvent && len(characters) > 1 && !foundGroups[groupKey] {
+			foundGroups[groupKey] = true
+			suggestions = append(suggestions, suggestion)
+		}
+	}
+
+	return suggestions, nil
+}