feat(tools): code_search (single-repo)

Adds SearchCode to gitea.Client and code_search MCP tool for single-repo
code search via GET /api/v1/repos/{owner}/{repo}/search?type=code.
Fan-out placeholder returns ErrValidation (lands in 7.3).

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

internal/tools/code_search.go

@@ -0,0 +1,104 @@
+package tools
+
+import (
+	"context"
+	"encoding/json"
+	"fmt"
+
+	"gitea.d-ma.be/mathias/gitea-mcp/internal/allowlist"
+	"gitea.d-ma.be/mathias/gitea-mcp/internal/gitea"
+	"gitea.d-ma.be/mathias/gitea-mcp/internal/registry"
+)
+
+type CodeSearch struct {
+	c *gitea.Client
+	a *allowlist.Allowlist
+}
+
+func NewCodeSearch(c *gitea.Client, a *allowlist.Allowlist) *CodeSearch {
+	return &CodeSearch{c: c, a: a}
+}
+
+func (t *CodeSearch) Descriptor() registry.ToolDescriptor {
+	return registry.ToolDescriptor{
+		Name:        "code_search",
+		Description: "Search code across one repo or fan out across an owner's repos.",
+		InputSchema: json.RawMessage(`{
+			"type":"object",
+			"properties":{
+				"q":{"type":"string"},
+				"owner":{"type":"string"},
+				"repo":{"type":"string"},
+				"page":{"type":"integer","minimum":1},
+				"limit":{"type":"integer","minimum":1,"maximum":50}
+			},
+			"required":["q","owner"]
+		}`),
+	}
+}
+
+type codeSearchArgs struct {
+	Q     string `json:"q"`
+	Owner string `json:"owner"`
+	Repo  string `json:"repo"`
+	Page  int    `json:"page"`
+	Limit int    `json:"limit"`
+}
+
+type codeSearchResult struct {
+	Repo    string  `json:"repo"`
+	Path    string  `json:"path"`
+	Snippet string  `json:"snippet"`
+	Score   float64 `json:"score"`
+	HTMLURL string  `json:"html_url"`
+}
+
+func (t *CodeSearch) Call(ctx context.Context, raw json.RawMessage) (json.RawMessage, error) {
+	var args codeSearchArgs
+	if err := parseArgs(raw, &args); err != nil {
+		return nil, err
+	}
+	if args.Q == "" {
+		return nil, fmt.Errorf("q is required: %w", gitea.ErrValidation)
+	}
+	if err := t.a.Check(args.Owner); err != nil {
+		return nil, err
+	}
+	if args.Page < 1 {
+		args.Page = 1
+	}
+	if args.Limit < 1 || args.Limit > 50 {
+		args.Limit = 30
+	}
+
+	if args.Repo == "" {
+		// Phase 7.2: leave fan-out unimplemented — just error out for now.
+		return nil, fmt.Errorf("repo is required for single-repo search (org-wide fan-out lands in 7.3): %w", gitea.ErrValidation)
+	}
+
+	hits, err := t.c.SearchCode(ctx, args.Owner, args.Repo, args.Q, args.Page, args.Limit)
+	if err != nil {
+		return nil, err
+	}
+
+	results := make([]codeSearchResult, 0, len(hits))
+	repoFull := args.Owner + "/" + args.Repo
+	for _, h := range hits {
+		score := h.Score
+		if score == 0 {
+			score = 1.0
+		}
+		results = append(results, codeSearchResult{
+			Repo:    repoFull,
+			Path:    h.Path,
+			Snippet: h.Snippet,
+			Score:   score,
+			HTMLURL: h.HTMLURL,
+		})
+	}
+	out := map[string]any{"results": results}
+	if len(hits) == args.Limit {
+		out["next_page"] = args.Page + 1
+	}
+	return textOK(out)
+}

internal/tools/code_search_test.go

@@ -0,0 +1,73 @@
+package tools_test
+
+import (
+	"context"
+	"encoding/json"
+	"errors"
+	"net/http"
+	"net/http/httptest"
+	"testing"
+
+	"gitea.d-ma.be/mathias/gitea-mcp/internal/allowlist"
+	"gitea.d-ma.be/mathias/gitea-mcp/internal/gitea"
+	"gitea.d-ma.be/mathias/gitea-mcp/internal/tools"
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+func TestCodeSearchSingleRepo(t *testing.T) {
+	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		assert.Equal(t, "/api/v1/repos/mathias/infra/search", r.URL.Path)
+		assert.Equal(t, "ListRepos", r.URL.Query().Get("q"))
+		assert.Equal(t, "code", r.URL.Query().Get("type"))
+		w.Header().Set("Content-Type", "application/json")
+		_, _ = w.Write([]byte(`{
+			"data":[{
+				"path":"internal/gitea/repos.go",
+				"snippet":"func (c *Client) ListRepos",
+				"html_url":"http://gitea.example.com/mathias/infra/src/branch/main/internal/gitea/repos.go",
+				"score":3.0
+			}],
+			"ok":true
+		}`))
+	}))
+	defer srv.Close()
+
+	tool := tools.NewCodeSearch(gitea.NewClient(srv.URL, "tok"), allowlist.New([]string{"mathias"}))
+	out, err := tool.Call(context.Background(), json.RawMessage(`{"q":"ListRepos","owner":"mathias","repo":"infra"}`))
+	require.NoError(t, err)
+
+	var result struct {
+		Results []struct {
+			Repo    string  `json:"repo"`
+			Path    string  `json:"path"`
+			Snippet string  `json:"snippet"`
+			Score   float64 `json:"score"`
+		} `json:"results"`
+	}
+	require.NoError(t, json.Unmarshal(out, &result))
+	require.Len(t, result.Results, 1)
+	assert.Equal(t, "mathias/infra", result.Results[0].Repo)
+	assert.Equal(t, "internal/gitea/repos.go", result.Results[0].Path)
+	assert.Equal(t, "func (c *Client) ListRepos", result.Results[0].Snippet)
+}
+
+func TestCodeSearchAllowlistRejects(t *testing.T) {
+	tool := tools.NewCodeSearch(gitea.NewClient("http://unused", ""), allowlist.New([]string{"mathias"}))
+	_, err := tool.Call(context.Background(), json.RawMessage(`{"q":"foo","owner":"evil","repo":"infra"}`))
+	require.Error(t, err)
+}
+
+func TestCodeSearchRequiresQ(t *testing.T) {
+	tool := tools.NewCodeSearch(gitea.NewClient("http://unused", ""), allowlist.New([]string{"mathias"}))
+	_, err := tool.Call(context.Background(), json.RawMessage(`{"owner":"mathias","repo":"infra"}`))
+	require.Error(t, err)
+	assert.True(t, errors.Is(err, gitea.ErrValidation))
+}
+
+func TestCodeSearchFanOutNotYetImplemented(t *testing.T) {
+	tool := tools.NewCodeSearch(gitea.NewClient("http://unused", ""), allowlist.New([]string{"mathias"}))
+	_, err := tool.Call(context.Background(), json.RawMessage(`{"q":"foo","owner":"mathias"}`))
+	require.Error(t, err)
+	assert.True(t, errors.Is(err, gitea.ErrValidation))
+}