Merge pull request #185 from Quaver/mapset-search-advanced

Introduce new advanced searching of mapsets

Author: Swan

db/advanced_mapset_search.go

@@ -0,0 +1,343 @@
+package db
+
+import (
+	"fmt"
+	"math"
+	"regexp"
+	"strconv"
+	"strings"
+
+	"github.com/Quaver/api2/enums"
+)
+
+var advancedSearchFilterPattern = regexp.MustCompile(`^([A-Za-z]+)(<=|>=|=|<|>)(\S+)$`)
+var advancedSearchFilterLikePattern = regexp.MustCompile(`^[A-Za-z]+(?:<=|>=|=|<|>).*$`)
+
+type advancedRangeBound struct {
+	floatValue float64
+	intValue   int64
+	inclusive  bool
+}
+
+type advancedRangeConstraint struct {
+	integer bool
+	lower   *advancedRangeBound
+	upper   *advancedRangeBound
+}
+
+type parsedAdvancedSearch struct {
+	text        string
+	modes       []enums.GameMode
+	statuses    []enums.RankedStatus
+	ranges      map[string]advancedRangeConstraint
+	tags        []string
+	hasModes    bool
+	hasStatuses bool
+	clanRanked  bool
+}
+
+// ApplyAdvancedSearch parses advanced_search after normal query binding. It deliberately
+// only runs for the public mapset-search endpoint, which calls this method.
+func (options *ElasticMapsetSearchOptions) ApplyAdvancedSearch() error {
+	expression := strings.TrimSpace(options.AdvancedSearch)
+	if expression == "" {
+		return nil
+	}
+
+	parsed, err := parseAdvancedSearch(expression)
+	if err != nil {
+		return err
+	}
+
+	options.Search = parsed.text
+	options.advancedRanges = parsed.ranges
+	options.advancedTags = parsed.tags
+
+	if parsed.hasModes {
+		options.Mode = parsed.modes
+	}
+
+	if parsed.hasStatuses {
+		options.RankedStatus = parsed.statuses
+	}
+
+	if parsed.clanRanked {
+		options.IsClanRanked = true
+	}
+
+	return nil
+}
+
+func parseAdvancedSearch(expression string) (*parsedAdvancedSearch, error) {
+	parsed := &parsedAdvancedSearch{ranges: make(map[string]advancedRangeConstraint)}
+	text := make([]string, 0)
+	modeSeen := make(map[enums.GameMode]bool)
+	statusSeen := make(map[enums.RankedStatus]bool)
+	tagSeen := make(map[string]bool)
+
+	for _, token := range strings.Fields(expression) {
+		matches := advancedSearchFilterPattern.FindStringSubmatch(token)
+		if matches == nil {
+			if advancedSearchFilterLikePattern.MatchString(token) {
+				return nil, fmt.Errorf("invalid advanced search filter %q", token)
+			}
+
+			text = append(text, token)
+			continue
+		}
+
+		field, operator, value := strings.ToLower(matches[1]), matches[2], matches[3]
+		switch field {
+		case "t":
+			if operator != "=" {
+				return nil, fmt.Errorf("advanced search filter %q only supports =", field)
+			}
+
+			tag, err := advancedSearchTag(value)
+			if err != nil {
+				return nil, err
+			}
+
+			if !tagSeen[tag] {
+				parsed.tags = append(parsed.tags, tag)
+				tagSeen[tag] = true
+			}
+		case "k":
+			if operator != "=" {
+				return nil, fmt.Errorf("advanced search filter %q only supports =", field)
+			}
+
+			mode, err := gameModeFromKeyCount(value)
+			if err != nil {
+				return nil, err
+			}
+
+			parsed.hasModes = true
+			if !modeSeen[mode] {
+				parsed.modes = append(parsed.modes, mode)
+				modeSeen[mode] = true
+			}
+		case "s":
+			if operator != "=" {
+				return nil, fmt.Errorf("advanced search filter %q only supports =", field)
+			}
+			if strings.EqualFold(value, "c") {
+				parsed.clanRanked = true
+				continue
+			}
+
+			status, err := rankedStatusFromAdvancedSearch(value)
+			if err != nil {
+				return nil, err
+			}
+
+			parsed.hasStatuses = true
+			if !statusSeen[status] {
+				parsed.statuses = append(parsed.statuses, status)
+				statusSeen[status] = true
+			}
+		case "b", "d", "l", "ln", "pc", "lu":
+			fieldName, integer := advancedRangeField(field)
+			bound, err := parseAdvancedRangeBound(value, operator, integer)
+			if err != nil {
+				return nil, fmt.Errorf("invalid value for advanced search filter %q: %w", field, err)
+			}
+
+			constraint := parsed.ranges[fieldName]
+			constraint.integer = integer
+			if err := constraint.add(operator, bound); err != nil {
+				return nil, fmt.Errorf("invalid advanced search filter %q: %w", field, err)
+			}
+			parsed.ranges[fieldName] = constraint
+		default:
+			return nil, fmt.Errorf("unknown advanced search filter %q", field)
+		}
+	}
+
+	parsed.text = strings.Join(text, " ")
+	return parsed, nil
+}
+
+func advancedSearchTag(value string) (string, error) {
+	tag := strings.ToLower(value)
+	tag = strings.NewReplacer("_", " ", "-", " ").Replace(tag)
+	for _, validTag := range tagSearchTerms {
+		if tag == validTag {
+			return validTag, nil
+		}
+	}
+
+	return "", fmt.Errorf("invalid tag %q", value)
+}
+
+func advancedRangeField(field string) (string, bool) {
+	switch field {
+	case "b":
+		return "bpm", false
+	case "d":
+		return "difficulty_rating", false
+	case "l":
+		return "length", false
+	case "ln":
+		return "long_note_percentage", false
+	case "pc":
+		return "play_count", true
+	case "lu":
+		return "date_last_updated", true
+	default:
+		panic("unsupported advanced range field")
+	}
+}
+
+func parseAdvancedRangeBound(value, operator string, integer bool) (advancedRangeBound, error) {
+	bound := advancedRangeBound{inclusive: operator == "=" || operator == ">=" || operator == "<="}
+
+	if integer {
+		parsed, err := strconv.ParseInt(value, 10, 64)
+		if err != nil {
+			return advancedRangeBound{}, fmt.Errorf("must be an integer")
+		}
+		bound.intValue = parsed
+		return bound, nil
+	}
+
+	parsed, err := strconv.ParseFloat(value, 64)
+	if err != nil || math.IsNaN(parsed) || math.IsInf(parsed, 0) {
+		return advancedRangeBound{}, fmt.Errorf("must be a finite number")
+	}
+	bound.floatValue = parsed
+	return bound, nil
+}
+
+func (constraint *advancedRangeConstraint) add(operator string, bound advancedRangeBound) error {
+	if operator == "=" {
+		constraint.addLower(bound)
+		constraint.addUpper(bound)
+	} else if operator == ">" || operator == ">=" {
+		constraint.addLower(bound)
+	} else {
+		constraint.addUpper(bound)
+	}
+
+	if constraint.lower == nil || constraint.upper == nil {
+		return nil
+	}
+
+	comparison := constraint.compare(*constraint.lower, *constraint.upper)
+	if comparison > 0 || comparison == 0 && (!constraint.lower.inclusive || !constraint.upper.inclusive) {
+		return fmt.Errorf("range bounds do not overlap")
+	}
+
+	return nil
+}
+
+func (constraint *advancedRangeConstraint) addLower(bound advancedRangeBound) {
+	if constraint.lower == nil || constraint.compare(bound, *constraint.lower) > 0 ||
+		constraint.compare(bound, *constraint.lower) == 0 && !bound.inclusive && constraint.lower.inclusive {
+		constraint.lower = &bound
+	}
+}
+
+func (constraint *advancedRangeConstraint) addUpper(bound advancedRangeBound) {
+	if constraint.upper == nil || constraint.compare(bound, *constraint.upper) < 0 ||
+		constraint.compare(bound, *constraint.upper) == 0 && !bound.inclusive && constraint.upper.inclusive {
+		constraint.upper = &bound
+	}
+}
+
+func (constraint advancedRangeConstraint) compare(left, right advancedRangeBound) int {
+	if constraint.integer {
+		switch {
+		case left.intValue < right.intValue:
+			return -1
+		case left.intValue > right.intValue:
+			return 1
+		default:
+			return 0
+		}
+	}
+
+	switch {
+	case left.floatValue < right.floatValue:
+		return -1
+	case left.floatValue > right.floatValue:
+		return 1
+	default:
+		return 0
+	}
+}
+
+func gameModeFromKeyCount(value string) (enums.GameMode, error) {
+	keyCount, err := strconv.Atoi(value)
+	if err != nil {
+		return 0, fmt.Errorf("invalid game mode %q", value)
+	}
+
+	modes := map[int]enums.GameMode{
+		1: enums.GameModeKeys1, 2: enums.GameModeKeys2, 3: enums.GameModeKeys3,
+		4: enums.GameModeKeys4, 5: enums.GameModeKeys5, 6: enums.GameModeKeys6,
+		7: enums.GameModeKeys7, 8: enums.GameModeKeys8, 9: enums.GameModeKeys9,
+		10: enums.GameModeKeys10,
+	}
+
+	mode, exists := modes[keyCount]
+	if !exists {
+		return 0, fmt.Errorf("invalid game mode %q", value)
+	}
+
+	return mode, nil
+}
+
+func rankedStatusFromAdvancedSearch(value string) (enums.RankedStatus, error) {
+	switch strings.ToLower(value) {
+	case "r":
+		return enums.RankedStatusRanked, nil
+	case "u":
+		return enums.RankedStatusUnranked, nil
+	default:
+		return 0, fmt.Errorf("invalid ranked status %q (expected r, u, or c)", value)
+	}
+}
+
+func addSearchRangeQuery[T Number](boolQuery *BoolQuery, options *ElasticMapsetSearchOptions, field string, min T, max T) {
+	if constraint, exists := options.advancedRanges[field]; exists {
+		addAdvancedRangeQuery(boolQuery, field, constraint)
+		return
+	}
+
+	addRangeQuery(boolQuery, field, min, max)
+}
+
+func addAdvancedRangeQuery(boolQuery *BoolQuery, field string, constraint advancedRangeConstraint) {
+	rangeQuery := Range{}
+
+	if constraint.lower != nil {
+		value := advancedRangeValue(*constraint.lower, constraint.integer)
+		if constraint.lower.inclusive {
+			rangeQuery.Gte = value
+		} else {
+			rangeQuery.Gt = value
+		}
+	}
+
+	if constraint.upper != nil {
+		value := advancedRangeValue(*constraint.upper, constraint.integer)
+		if constraint.upper.inclusive {
+			rangeQuery.Lte = value
+		} else {
+			rangeQuery.Lt = value
+		}
+	}
+
+	boolQuery.BoolQuery.Must = append(boolQuery.BoolQuery.Must, RangeCustom{
+		Range: map[string]Range{field: rangeQuery},
+	})
+}
+
+func advancedRangeValue(bound advancedRangeBound, integer bool) interface{} {
+	if integer {
+		return bound.intValue
+	}
+
+	return bound.floatValue
+}