2 files changed, 398 insertions, 0 deletions

diff --git a/modules/indexer/issues/meilisearch/meilisearch.go b/modules/indexer/issues/meilisearch/meilisearch.go
new file mode 100644
index 00000000..93323193
--- /dev/null
+++ b/modules/indexer/issues/meilisearch/meilisearch.go
@@ -0,0 +1,301 @@
+// Copyright 2023 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package meilisearch
+
+import (
+	"context"
+	"errors"
+	"fmt"
+	"strconv"
+	"strings"
+
+	indexer_internal "code.gitea.io/gitea/modules/indexer/internal"
+	inner_meilisearch "code.gitea.io/gitea/modules/indexer/internal/meilisearch"
+	"code.gitea.io/gitea/modules/indexer/issues/internal"
+
+	"github.com/meilisearch/meilisearch-go"
+)
+
+const (
+	issueIndexerLatestVersion = 3
+
+	// TODO: make this configurable if necessary
+	maxTotalHits = 10000
+)
+
+// ErrMalformedResponse is never expected as we initialize the indexer ourself and so define the types.
+var ErrMalformedResponse = errors.New("meilisearch returned unexpected malformed content")
+
+var _ internal.Indexer = &Indexer{}
+
+// Indexer implements Indexer interface
+type Indexer struct {
+	inner                    *inner_meilisearch.Indexer
+	indexer_internal.Indexer // do not composite inner_meilisearch.Indexer directly to avoid exposing too much
+}
+
+// NewIndexer creates a new meilisearch indexer
+func NewIndexer(url, apiKey, indexerName string) *Indexer {
+	settings := &meilisearch.Settings{
+		// The default ranking rules of meilisearch are: ["words", "typo", "proximity", "attribute", "sort", "exactness"]
+		// So even if we specify the sort order, it could not be respected because the priority of "sort" is so low.
+		// So we need to specify the ranking rules to make sure the sort order is respected.
+		// See https://www.meilisearch.com/docs/learn/core_concepts/relevancy
+		RankingRules: []string{"sort", // make sure "sort" has the highest priority
+			"words", "typo", "proximity", "attribute", "exactness"},
+
+		SearchableAttributes: []string{
+			"title",
+			"content",
+			"comments",
+		},
+		DisplayedAttributes: []string{
+			"id",
+			"title",
+			"content",
+			"comments",
+		},
+		FilterableAttributes: []string{
+			"repo_id",
+			"is_public",
+			"is_pull",
+			"is_closed",
+			"label_ids",
+			"no_label",
+			"milestone_id",
+			"project_id",
+			"project_board_id",
+			"poster_id",
+			"assignee_id",
+			"mention_ids",
+			"reviewed_ids",
+			"review_requested_ids",
+			"subscriber_ids",
+			"updated_unix",
+		},
+		SortableAttributes: []string{
+			"updated_unix",
+			"created_unix",
+			"deadline_unix",
+			"comment_count",
+			"id",
+		},
+		Pagination: &meilisearch.Pagination{
+			MaxTotalHits: maxTotalHits,
+		},
+	}
+
+	inner := inner_meilisearch.NewIndexer(url, apiKey, indexerName, issueIndexerLatestVersion, settings)
+	indexer := &Indexer{
+		inner:   inner,
+		Indexer: inner,
+	}
+	return indexer
+}
+
+// Index will save the index data
+func (b *Indexer) Index(_ context.Context, issues ...*internal.IndexerData) error {
+	if len(issues) == 0 {
+		return nil
+	}
+	for _, issue := range issues {
+		_, err := b.inner.Client.Index(b.inner.VersionedIndexName()).AddDocuments(issue)
+		if err != nil {
+			return err
+		}
+	}
+	// TODO: bulk send index data
+	return nil
+}
+
+// Delete deletes indexes by ids
+func (b *Indexer) Delete(_ context.Context, ids ...int64) error {
+	if len(ids) == 0 {
+		return nil
+	}
+
+	for _, id := range ids {
+		_, err := b.inner.Client.Index(b.inner.VersionedIndexName()).DeleteDocument(strconv.FormatInt(id, 10))
+		if err != nil {
+			return err
+		}
+	}
+	// TODO: bulk send deletes
+	return nil
+}
+
+// Search searches for issues by given conditions.
+// Returns the matching issue IDs
+func (b *Indexer) Search(ctx context.Context, options *internal.SearchOptions) (*internal.SearchResult, error) {
+	query := inner_meilisearch.FilterAnd{}
+
+	if len(options.RepoIDs) > 0 {
+		q := &inner_meilisearch.FilterOr{}
+		q.Or(inner_meilisearch.NewFilterIn("repo_id", options.RepoIDs...))
+		if options.AllPublic {
+			q.Or(inner_meilisearch.NewFilterEq("is_public", true))
+		}
+		query.And(q)
+	}
+
+	if options.IsPull.Has() {
+		query.And(inner_meilisearch.NewFilterEq("is_pull", options.IsPull.Value()))
+	}
+	if options.IsClosed.Has() {
+		query.And(inner_meilisearch.NewFilterEq("is_closed", options.IsClosed.Value()))
+	}
+
+	if options.NoLabelOnly {
+		query.And(inner_meilisearch.NewFilterEq("no_label", true))
+	} else {
+		if len(options.IncludedLabelIDs) > 0 {
+			q := &inner_meilisearch.FilterAnd{}
+			for _, labelID := range options.IncludedLabelIDs {
+				q.And(inner_meilisearch.NewFilterEq("label_ids", labelID))
+			}
+			query.And(q)
+		} else if len(options.IncludedAnyLabelIDs) > 0 {
+			query.And(inner_meilisearch.NewFilterIn("label_ids", options.IncludedAnyLabelIDs...))
+		}
+		if len(options.ExcludedLabelIDs) > 0 {
+			q := &inner_meilisearch.FilterAnd{}
+			for _, labelID := range options.ExcludedLabelIDs {
+				q.And(inner_meilisearch.NewFilterNot(inner_meilisearch.NewFilterEq("label_ids", labelID)))
+			}
+			query.And(q)
+		}
+	}
+
+	if len(options.MilestoneIDs) > 0 {
+		query.And(inner_meilisearch.NewFilterIn("milestone_id", options.MilestoneIDs...))
+	}
+
+	if options.ProjectID.Has() {
+		query.And(inner_meilisearch.NewFilterEq("project_id", options.ProjectID.Value()))
+	}
+	if options.ProjectColumnID.Has() {
+		query.And(inner_meilisearch.NewFilterEq("project_board_id", options.ProjectColumnID.Value()))
+	}
+
+	if options.PosterID.Has() {
+		query.And(inner_meilisearch.NewFilterEq("poster_id", options.PosterID.Value()))
+	}
+
+	if options.AssigneeID.Has() {
+		query.And(inner_meilisearch.NewFilterEq("assignee_id", options.AssigneeID.Value()))
+	}
+
+	if options.MentionID.Has() {
+		query.And(inner_meilisearch.NewFilterEq("mention_ids", options.MentionID.Value()))
+	}
+
+	if options.ReviewedID.Has() {
+		query.And(inner_meilisearch.NewFilterEq("reviewed_ids", options.ReviewedID.Value()))
+	}
+	if options.ReviewRequestedID.Has() {
+		query.And(inner_meilisearch.NewFilterEq("review_requested_ids", options.ReviewRequestedID.Value()))
+	}
+
+	if options.SubscriberID.Has() {
+		query.And(inner_meilisearch.NewFilterEq("subscriber_ids", options.SubscriberID.Value()))
+	}
+
+	if options.UpdatedAfterUnix.Has() {
+		query.And(inner_meilisearch.NewFilterGte("updated_unix", options.UpdatedAfterUnix.Value()))
+	}
+	if options.UpdatedBeforeUnix.Has() {
+		query.And(inner_meilisearch.NewFilterLte("updated_unix", options.UpdatedBeforeUnix.Value()))
+	}
+
+	if options.SortBy == "" {
+		options.SortBy = internal.SortByCreatedAsc
+	}
+	sortBy := []string{
+		parseSortBy(options.SortBy),
+		"id:desc",
+	}
+
+	skip, limit := indexer_internal.ParsePaginator(options.Paginator, maxTotalHits)
+
+	counting := limit == 0
+	if counting {
+		// If set limit to 0, it will be 20 by default, and -1 is not allowed.
+		// See https://www.meilisearch.com/docs/reference/api/search#limit
+		// So set limit to 1 to make the cost as low as possible, then clear the result before returning.
+		limit = 1
+	}
+
+	keyword := options.Keyword
+	if !options.IsFuzzyKeyword {
+		// to make it non fuzzy ("typo tolerance" in meilisearch terms), we have to quote the keyword(s)
+		// https://www.meilisearch.com/docs/reference/api/search#phrase-search
+		keyword = doubleQuoteKeyword(keyword)
+	}
+
+	searchRes, err := b.inner.Client.Index(b.inner.VersionedIndexName()).Search(keyword, &meilisearch.SearchRequest{
+		Filter:           query.Statement(),
+		Limit:            int64(limit),
+		Offset:           int64(skip),
+		Sort:             sortBy,
+		MatchingStrategy: "all",
+	})
+	if err != nil {
+		return nil, err
+	}
+
+	if counting {
+		searchRes.Hits = nil
+	}
+
+	hits, err := convertHits(searchRes)
+	if err != nil {
+		return nil, err
+	}
+
+	return &internal.SearchResult{
+		Total: searchRes.EstimatedTotalHits,
+		Hits:  hits,
+	}, nil
+}
+
+func parseSortBy(sortBy internal.SortBy) string {
+	field := strings.TrimPrefix(string(sortBy), "-")
+	if strings.HasPrefix(string(sortBy), "-") {
+		return field + ":desc"
+	}
+	return field + ":asc"
+}
+
+func doubleQuoteKeyword(k string) string {
+	kp := strings.Split(k, " ")
+	parts := 0
+	for i := range kp {
+		part := strings.Trim(kp[i], "\"")
+		if part != "" {
+			kp[parts] = fmt.Sprintf(`"%s"`, part)
+			parts++
+		}
+	}
+	return strings.Join(kp[:parts], " ")
+}
+
+func convertHits(searchRes *meilisearch.SearchResponse) ([]internal.Match, error) {
+	hits := make([]internal.Match, 0, len(searchRes.Hits))
+	for _, hit := range searchRes.Hits {
+		hit, ok := hit.(map[string]any)
+		if !ok {
+			return nil, ErrMalformedResponse
+		}
+
+		issueID, ok := hit["id"].(float64)
+		if !ok {
+			return nil, ErrMalformedResponse
+		}
+
+		hits = append(hits, internal.Match{
+			ID: int64(issueID),
+		})
+	}
+	return hits, nil
+}
diff --git a/modules/indexer/issues/meilisearch/meilisearch_test.go b/modules/indexer/issues/meilisearch/meilisearch_test.go
new file mode 100644
index 00000000..349102b7
--- /dev/null
+++ b/modules/indexer/issues/meilisearch/meilisearch_test.go
@@ -0,0 +1,97 @@
+// Copyright 2023 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package meilisearch
+
+import (
+	"fmt"
+	"net/http"
+	"os"
+	"testing"
+	"time"
+
+	"code.gitea.io/gitea/modules/indexer/issues/internal"
+	"code.gitea.io/gitea/modules/indexer/issues/internal/tests"
+
+	"github.com/meilisearch/meilisearch-go"
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+func TestMeilisearchIndexer(t *testing.T) {
+	t.Skip("meilisearch not found in Forgejo test yet")
+	// The meilisearch instance started by pull-db-tests.yml > test-unit > services > meilisearch
+	url := "http://meilisearch:7700"
+	key := "" // auth has been disabled in test environment
+
+	if os.Getenv("CI") == "" {
+		// Make it possible to run tests against a local meilisearch instance
+		url = os.Getenv("TEST_MEILISEARCH_URL")
+		if url == "" {
+			t.Skip("TEST_MEILISEARCH_URL not set and not running in CI")
+			return
+		}
+		key = os.Getenv("TEST_MEILISEARCH_KEY")
+	}
+
+	ok := false
+	for i := 0; i < 60; i++ {
+		resp, err := http.Get(url)
+		if err == nil && resp.StatusCode == http.StatusOK {
+			ok = true
+			break
+		}
+		t.Logf("Waiting for meilisearch to be up: %v", err)
+		time.Sleep(time.Second)
+	}
+	if !ok {
+		t.Fatalf("Failed to wait for meilisearch to be up")
+		return
+	}
+
+	indexer := NewIndexer(url, key, fmt.Sprintf("test_meilisearch_indexer_%d", time.Now().Unix()))
+	defer indexer.Close()
+
+	tests.TestIndexer(t, indexer)
+}
+
+func TestConvertHits(t *testing.T) {
+	_, err := convertHits(&meilisearch.SearchResponse{
+		Hits: []any{"aa", "bb", "cc", "dd"},
+	})
+	require.ErrorIs(t, err, ErrMalformedResponse)
+
+	validResponse := &meilisearch.SearchResponse{
+		Hits: []any{
+			map[string]any{
+				"id":       float64(11),
+				"title":    "a title",
+				"content":  "issue body with no match",
+				"comments": []any{"hey what's up?", "I'm currently bowling", "nice"},
+			},
+			map[string]any{
+				"id":       float64(22),
+				"title":    "Bowling as title",
+				"content":  "",
+				"comments": []any{},
+			},
+			map[string]any{
+				"id":       float64(33),
+				"title":    "Bowl-ing as fuzzy match",
+				"content":  "",
+				"comments": []any{},
+			},
+		},
+	}
+	hits, err := convertHits(validResponse)
+	require.NoError(t, err)
+	assert.EqualValues(t, []internal.Match{{ID: 11}, {ID: 22}, {ID: 33}}, hits)
+}
+
+func TestDoubleQuoteKeyword(t *testing.T) {
+	assert.EqualValues(t, "", doubleQuoteKeyword(""))
+	assert.EqualValues(t, `"a" "b" "c"`, doubleQuoteKeyword("a b c"))
+	assert.EqualValues(t, `"a" "d" "g"`, doubleQuoteKeyword("a  d g"))
+	assert.EqualValues(t, `"a" "d" "g"`, doubleQuoteKeyword("a  d g"))
+	assert.EqualValues(t, `"a" "d" "g"`, doubleQuoteKeyword(`a  "" "d" """g`))
+}