package tools_test

import (
	"context"
	"encoding/base64"
	"encoding/json"
	"errors"
	"fmt"
	"net/http"
	"net/http/httptest"
	"strings"
	"testing"

	"git.d-ma.be/mathias/gitea-mcp/internal/allowlist"
	"git.d-ma.be/mathias/gitea-mcp/internal/gitea"
	"git.d-ma.be/mathias/gitea-mcp/internal/tools"
	"github.com/stretchr/testify/assert"
	"github.com/stretchr/testify/require"
)

// multiRepoSearchFake serves ListRepos + per-repo GetRepo/GetTree/GetFileContents
// for a set of repos — the real endpoints code_search's underlying SearchCode
// now uses (Gitea's REST API has no code-content-search endpoint; see
// internal/gitea/code_search.go's doc comment).
type multiRepoSearchFake struct {
	owner string
	repos []string                     // ListRepos response, in this order
	files map[string]map[string]string // repo -> path -> content
	fail  map[string]bool              // repo -> GetRepo 500s for this repo (simulates a per-repo failure)
}

func (f *multiRepoSearchFake) handler(t *testing.T) http.HandlerFunc {
	return func(w http.ResponseWriter, r *http.Request) {
		w.Header().Set("Content-Type", "application/json")
		p := r.URL.Path

		for _, repo := range f.repos {
			base := "/api/v1/repos/" + f.owner + "/" + repo
			switch {
			case p == base && f.fail[repo]:
				w.WriteHeader(http.StatusInternalServerError)
				_, _ = w.Write([]byte(`{"message":"internal error"}`))
				return
			case p == base:
				_, _ = fmt.Fprintf(w, `{"name":%q,"full_name":"%s/%s","default_branch":"main"}`, repo, f.owner, repo)
				return
			case strings.HasPrefix(p, base+"/git/trees/"):
				var entries []string
				for path := range f.files[repo] {
					entries = append(entries, fmt.Sprintf(`{"path":%q,"type":"blob","sha":"s","size":100}`, path))
				}
				_, _ = fmt.Fprintf(w, `{"sha":"root","tree":[%s],"truncated":false}`, strings.Join(entries, ","))
				return
			case strings.HasPrefix(p, base+"/contents/"):
				path := strings.TrimPrefix(p, base+"/contents/")
				content, ok := f.files[repo][path]
				if !ok {
					w.WriteHeader(http.StatusNotFound)
					_, _ = w.Write([]byte(`{"message":"not found"}`))
					return
				}
				enc := base64.StdEncoding.EncodeToString([]byte(content))
				_, _ = fmt.Fprintf(w, `{"path":%q,"sha":"s","size":%d,"content":%q,"encoding":"base64"}`, path, len(content), enc)
				return
			}
		}

		if p == "/api/v1/users/"+f.owner+"/repos" {
			var entries []string
			for _, repo := range f.repos {
				entries = append(entries, fmt.Sprintf(`{"name":%q,"full_name":"%s/%s","default_branch":"main"}`, repo, f.owner, repo))
			}
			_, _ = fmt.Fprintf(w, `[%s]`, strings.Join(entries, ","))
			return
		}

		t.Errorf("unexpected request: %s %s", r.Method, p)
		w.WriteHeader(http.StatusNotFound)
	}
}

func TestCodeSearchSingleRepo(t *testing.T) {
	f := &multiRepoSearchFake{
		owner: "mathias",
		repos: []string{"infra"},
		files: map[string]map[string]string{
			"infra": {"internal/gitea/repos.go": "func (c *Client) ListRepos() {}\n"},
		},
	}
	srv := httptest.NewServer(f.handler(t))
	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.Contains(t, result.Results[0].Snippet, "ListRepos")
}

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 TestCodeSearchFanOutHappyPath(t *testing.T) {
	f := &multiRepoSearchFake{
		owner: "mathias",
		repos: []string{"infra", "gitea-mcp"},
		files: map[string]map[string]string{
			"infra":     {"main.go": "this is an infra hit\n"},
			"gitea-mcp": {"cmd/main.go": "this is a gitea-mcp hit\n"},
		},
	}
	srv := httptest.NewServer(f.handler(t))
	defer srv.Close()

	tool := tools.NewCodeSearch(gitea.NewClient(srv.URL, "tok"), allowlist.New([]string{"mathias"}))
	out, err := tool.Call(context.Background(), json.RawMessage(`{"q":"hit","owner":"mathias"}`))
	require.NoError(t, err)

	var result struct {
		Results []struct {
			Repo    string `json:"repo"`
			Path    string `json:"path"`
			Snippet string `json:"snippet"`
		} `json:"results"`
		Partial bool `json:"partial"`
	}
	require.NoError(t, json.Unmarshal(out, &result))
	assert.False(t, result.Partial)
	require.Len(t, result.Results, 2)

	repos := make([]string, 0, 2)
	for _, r := range result.Results {
		repos = append(repos, r.Repo)
	}
	assert.Contains(t, repos, "mathias/infra")
	assert.Contains(t, repos, "mathias/gitea-mcp")
}

func TestCodeSearchFanOutPartialFailure(t *testing.T) {
	f := &multiRepoSearchFake{
		owner: "mathias",
		repos: []string{"infra", "broken"},
		files: map[string]map[string]string{
			"infra": {"main.go": "this is an infra hit\n"},
		},
		fail: map[string]bool{"broken": true},
	}
	srv := httptest.NewServer(f.handler(t))
	defer srv.Close()

	tool := tools.NewCodeSearch(gitea.NewClient(srv.URL, "tok"), allowlist.New([]string{"mathias"}))
	out, err := tool.Call(context.Background(), json.RawMessage(`{"q":"hit","owner":"mathias"}`))
	require.NoError(t, err)

	var result struct {
		Results []struct {
			Repo string `json:"repo"`
		} `json:"results"`
		Partial      bool     `json:"partial"`
		PartialRepos []string `json:"partial_repos"`
	}
	require.NoError(t, json.Unmarshal(out, &result))
	assert.True(t, result.Partial)
	require.Len(t, result.PartialRepos, 1)
	assert.Equal(t, "mathias/broken", result.PartialRepos[0])
	require.Len(t, result.Results, 1)
	assert.Equal(t, "mathias/infra", result.Results[0].Repo)
}

func TestCodeSearchFanOutSortsByScore(t *testing.T) {
	f := &multiRepoSearchFake{
		owner: "mathias",
		repos: []string{"alpha", "beta"},
		files: map[string]map[string]string{
			"alpha": {"a.go": "one high here"},            // 1 occurrence => score 1
			"beta":  {"b.go": "high high high high high"}, // 5 occurrences => score 5
		},
	}
	srv := httptest.NewServer(f.handler(t))
	defer srv.Close()

	tool := tools.NewCodeSearch(gitea.NewClient(srv.URL, "tok"), allowlist.New([]string{"mathias"}))
	out, err := tool.Call(context.Background(), json.RawMessage(`{"q":"high","owner":"mathias"}`))
	require.NoError(t, err)

	var result struct {
		Results []struct {
			Repo    string  `json:"repo"`
			Snippet string  `json:"snippet"`
			Score   float64 `json:"score"`
		} `json:"results"`
	}
	require.NoError(t, json.Unmarshal(out, &result))
	require.Len(t, result.Results, 2)
	assert.Equal(t, "mathias/beta", result.Results[0].Repo, "higher-score repo (5 occurrences) must sort first")
	assert.True(t, result.Results[0].Score > result.Results[1].Score,
		"expected results sorted by score desc, got %v then %v", result.Results[0].Score, result.Results[1].Score)
}