package server

import (
	"context"
	"encoding/json"
	"fmt"
	"log/slog"
	"net/http"
	"net/http/httptest"
	"slices"
	"strings"
	"sync"
	"testing"

	"gogs.netdome.biz/paul/go-wikijs-mcp/internal/wikijs"

	"github.com/modelcontextprotocol/go-sdk/mcp"
)

type capturedRequest struct {
	Query     string         `json:"query"`
	Variables map[string]any `json:"variables"`
}

type fakeWiki struct {
	t        *testing.T
	mu       sync.Mutex
	requests []capturedRequest
}

func (f *fakeWiki) handle(w http.ResponseWriter, r *http.Request) {
	f.t.Helper()
	if got, want := r.Header.Get("Authorization"), "Bearer test-key"; got != want {
		f.t.Errorf("Authorization = %q, want %q", got, want)
	}

	var req capturedRequest
	if err := json.NewDecoder(r.Body).Decode(&req); err != nil {
		f.t.Errorf("decode request: %v", err)
		http.Error(w, "bad request", http.StatusBadRequest)
		return
	}
	f.mu.Lock()
	f.requests = append(f.requests, req)
	f.mu.Unlock()

	w.Header().Set("Content-Type", "application/json")
	switch {
	case strings.Contains(req.Query, "query SearchPages"):
		fmt.Fprint(w, `{"data":{"pages":{"search":{"results":[
			{"title":"MCP","description":"protocol","path":"/mcp","locale":"en"}
		],"suggestions":["mcp"],"totalHits":1}}}}`)

	case strings.Contains(req.Query, "query GetPageById"):
		id, _ := req.Variables["id"].(float64)
		if id == 404 {
			fmt.Fprint(w, `{"data":{"pages":{"single":null}}}`)
			return
		}
		fmt.Fprintf(w, `{"data":{"pages":{"single":{
			"id":%d,"path":"/dev/go","title":"Go","description":"desc",
			"tags":[{"tag":"go","title":"Go"}],"content":"body",
			"createdAt":"c","updatedAt":"u","locale":"de"}}}}`, int(id))

	case strings.Contains(req.Query, "query GetPageByPath"):
		path, _ := req.Variables["path"].(string)
		locale, _ := req.Variables["locale"].(string)
		fmt.Fprintf(w, `{"data":{"pages":{"singleByPath":{
			"id":7,"path":%q,"title":"Start","description":"desc",
			"tags":[],"content":"body","createdAt":"c","updatedAt":"u","locale":%q}}}}`, path, locale)

	case strings.Contains(req.Query, "query GetAllPages"):
		fmt.Fprint(w, `{"data":{"pages":{"list":[
			{"id":1,"path":"/a","locale":"de","title":"A","description":"a",
			 "createdAt":"c","updatedAt":"u","tags":["go"]}
		]}}}`)

	case strings.Contains(req.Query, "mutation CreatePage"):
		title, _ := req.Variables["title"].(string)
		if title == "fail" {
			fmt.Fprint(w, `{"data":{"pages":{"create":{"responseResult":{
				"succeeded":false,"errorCode":6001,"slug":"","message":"Nope"}}}}}`)
			return
		}
		fmt.Fprint(w, `{"data":{"pages":{"create":{"responseResult":{
			"succeeded":true,"errorCode":0,"slug":"new","message":"Page created"}}}}}`)

	case strings.Contains(req.Query, "mutation UpdatePage"):
		id, _ := req.Variables["id"].(float64)
		if id == 404 {
			fmt.Fprint(w, `{"data":{"pages":{"update":{"responseResult":{
				"succeeded":false,"errorCode":6001,"slug":"","message":"Page not found"}}}}}`)
			return
		}
		fmt.Fprint(w, `{"data":{"pages":{"update":{"responseResult":{
			"succeeded":true,"errorCode":0,"slug":"","message":"Page updated"}}}}}`)

	default:
		f.t.Errorf("unexpected query: %s", req.Query)
		http.Error(w, "unknown operation", http.StatusBadRequest)
	}
}

func (f *fakeWiki) lastContaining(t *testing.T, fragment string) capturedRequest {
	t.Helper()
	f.mu.Lock()
	defer f.mu.Unlock()
	for i := len(f.requests) - 1; i >= 0; i-- {
		if strings.Contains(f.requests[i].Query, fragment) {
			return f.requests[i]
		}
	}
	t.Fatalf("no request containing %q", fragment)
	return capturedRequest{}
}

func newTestSession(t *testing.T, enableEdit bool) (*mcp.ClientSession, *fakeWiki) {
	t.Helper()

	fake := &fakeWiki{t: t}
	wikiSrv := httptest.NewServer(http.HandlerFunc(fake.handle))
	t.Cleanup(wikiSrv.Close)

	wikiClient, err := wikijs.New(wikiSrv.URL, "test-key")
	if err != nil {
		t.Fatalf("wikijs.New() error = %v", err)
	}

	srv := New(wikiClient, Options{
		Version:    "test",
		EnableEdit: enableEdit,
		Logger:     slog.New(slog.DiscardHandler),
	})

	st, ct := mcp.NewInMemoryTransports()
	ctx := context.Background()
	ss, err := srv.Connect(ctx, st, nil)
	if err != nil {
		t.Fatalf("server connect: %v", err)
	}
	t.Cleanup(func() { _ = ss.Close() })

	client := mcp.NewClient(&mcp.Implementation{Name: "test-client", Version: "0"}, nil)
	cs, err := client.Connect(ctx, ct, nil)
	if err != nil {
		t.Fatalf("client connect: %v", err)
	}
	t.Cleanup(func() { _ = cs.Close() })

	return cs, fake
}

func callTool(t *testing.T, cs *mcp.ClientSession, name string, args map[string]any) *mcp.CallToolResult {
	t.Helper()
	res, err := cs.CallTool(context.Background(), &mcp.CallToolParams{Name: name, Arguments: args})
	if err != nil {
		t.Fatalf("CallTool(%s) error = %v", name, err)
	}
	return res
}

func toolText(t *testing.T, res *mcp.CallToolResult) string {
	t.Helper()
	if len(res.Content) == 0 {
		t.Fatal("tool result has no content")
	}
	text, ok := res.Content[0].(*mcp.TextContent)
	if !ok {
		t.Fatalf("content type = %T, want *mcp.TextContent", res.Content[0])
	}
	return text.Text
}

func TestToolListWithoutEdit(t *testing.T) {
	cs, _ := newTestSession(t, false)

	res, err := cs.ListTools(context.Background(), nil)
	if err != nil {
		t.Fatalf("ListTools() error = %v", err)
	}
	got := toolNames(res.Tools)
	want := []string{"search_pages", "get_page_by_id", "get_page_by_path", "get_all_pages"}
	if !equalNames(got, want) {
		t.Errorf("tools = %v, want %v", got, want)
	}
}

func TestToolListWithEdit(t *testing.T) {
	cs, _ := newTestSession(t, true)

	res, err := cs.ListTools(context.Background(), nil)
	if err != nil {
		t.Fatalf("ListTools() error = %v", err)
	}
	got := toolNames(res.Tools)
	want := []string{"search_pages", "get_page_by_id", "get_page_by_path", "get_all_pages", "create_page", "edit_page"}
	if !equalNames(got, want) {
		t.Errorf("tools = %v, want %v", got, want)
	}
}

func toolNames(tools []*mcp.Tool) []string {
	names := make([]string, len(tools))
	for i, tool := range tools {
		names[i] = tool.Name
	}
	return names
}

func equalNames(got, want []string) bool {
	got = slices.Clone(got)
	want = slices.Clone(want)
	slices.Sort(got)
	slices.Sort(want)
	return slices.Equal(got, want)
}

func TestSearchPagesTool(t *testing.T) {
	cs, fake := newTestSession(t, false)

	res := callTool(t, cs, "search_pages", map[string]any{"query": "mcp"})
	if res.IsError {
		t.Fatalf("IsError = true: %s", toolText(t, res))
	}
	if res.StructuredContent == nil {
		t.Error("StructuredContent = nil")
	}

	var out wikijs.SearchResults
	if err := json.Unmarshal([]byte(toolText(t, res)), &out); err != nil {
		t.Fatalf("decode result: %v", err)
	}
	if out.TotalHits != 1 || len(out.Results) != 1 {
		t.Fatalf("result = %+v", out)
	}
	if !strings.HasSuffix(out.Results[0].URL, "/mcp") {
		t.Errorf("URL = %q", out.Results[0].URL)
	}

	req := fake.lastContaining(t, "query SearchPages")
	if _, ok := req.Variables["path"]; ok {
		t.Errorf("path variable present: %v", req.Variables["path"])
	}
}

func TestSearchPagesValidation(t *testing.T) {
	cs, _ := newTestSession(t, false)

	tests := []struct {
		name string
		args map[string]any
		want string
	}{
		{name: "empty query", args: map[string]any{"query": "  "}, want: "query must not be empty"},
		{name: "bad locale", args: map[string]any{"query": "x", "locale": "english"}, want: "invalid locale"},
	}
	for _, tt := range tests {
		t.Run(tt.name, func(t *testing.T) {
			res := callTool(t, cs, "search_pages", tt.args)
			if !res.IsError {
				t.Fatal("IsError = false, want true")
			}
			if got := toolText(t, res); !strings.Contains(got, tt.want) {
				t.Errorf("text = %q, want substring %q", got, tt.want)
			}
		})
	}
}

func TestGetPageByIDTool(t *testing.T) {
	cs, _ := newTestSession(t, false)

	res := callTool(t, cs, "get_page_by_id", map[string]any{"id": 42})
	if res.IsError {
		t.Fatalf("IsError = true: %s", toolText(t, res))
	}
	var page wikijs.Page
	if err := json.Unmarshal([]byte(toolText(t, res)), &page); err != nil {
		t.Fatalf("decode page: %v", err)
	}
	if page.ID != 42 || page.Title != "Go" {
		t.Errorf("page = %+v", page)
	}
	if !strings.HasSuffix(page.URL, "/de/dev/go") {
		t.Errorf("URL = %q", page.URL)
	}
}

func TestGetPageByIDNotFound(t *testing.T) {
	cs, _ := newTestSession(t, false)

	res := callTool(t, cs, "get_page_by_id", map[string]any{"id": 404})
	if res.IsError {
		t.Fatalf("IsError = true: %s", toolText(t, res))
	}
	if got := strings.TrimSpace(toolText(t, res)); got != "null" {
		t.Errorf("text = %q, want null", got)
	}
}

func TestGetPageByIDInvalid(t *testing.T) {
	cs, _ := newTestSession(t, false)

	res := callTool(t, cs, "get_page_by_id", map[string]any{"id": 0})
	if !res.IsError {
		t.Fatal("IsError = false, want true")
	}
	if got := toolText(t, res); !strings.Contains(got, "positive") {
		t.Errorf("text = %q", got)
	}
}

func TestGetPageByPathTool(t *testing.T) {
	cs, _ := newTestSession(t, false)

	res := callTool(t, cs, "get_page_by_path", map[string]any{"path": "/start", "locale": "de-DE"})
	if res.IsError {
		t.Fatalf("IsError = true: %s", toolText(t, res))
	}
	var page wikijs.Page
	if err := json.Unmarshal([]byte(toolText(t, res)), &page); err != nil {
		t.Fatalf("decode page: %v", err)
	}
	if page.ID != 7 {
		t.Errorf("page = %+v", page)
	}
	if !strings.HasSuffix(page.URL, "/de-DE/start") {
		t.Errorf("URL = %q", page.URL)
	}
}

func TestGetPageByPathRequiresLocale(t *testing.T) {
	cs, _ := newTestSession(t, false)

	res := callTool(t, cs, "get_page_by_path", map[string]any{"path": "/start"})
	if !res.IsError {
		t.Fatal("IsError = false, want true")
	}
}

func TestListPagesTool(t *testing.T) {
	cs, fake := newTestSession(t, false)

	res := callTool(t, cs, "get_all_pages", map[string]any{
		"limit":  10,
		"locale": "de",
		"tags":   []string{"go"},
	})
	if res.IsError {
		t.Fatalf("IsError = true: %s", toolText(t, res))
	}
	var pages []wikijs.PageListItem
	if err := json.Unmarshal([]byte(toolText(t, res)), &pages); err != nil {
		t.Fatalf("decode pages: %v", err)
	}
	if len(pages) != 1 || pages[0].ID != 1 {
		t.Errorf("pages = %+v", pages)
	}

	req := fake.lastContaining(t, "query GetAllPages")
	if got := req.Variables["limit"]; got != float64(10) {
		t.Errorf("variables[limit] = %v", got)
	}
	if got := req.Variables["locale"]; got != "de" {
		t.Errorf("variables[locale] = %v", got)
	}
}

func TestListPagesValidation(t *testing.T) {
	cs, _ := newTestSession(t, false)

	res := callTool(t, cs, "get_all_pages", map[string]any{"limit": 0})
	if !res.IsError {
		t.Fatal("IsError = false, want true")
	}
	if got := toolText(t, res); !strings.Contains(got, "limit must be a positive integer") {
		t.Errorf("text = %q", got)
	}
}

func TestCreatePageDefaults(t *testing.T) {
	cs, fake := newTestSession(t, true)

	res := callTool(t, cs, "create_page", map[string]any{
		"title":       "New",
		"content":     "body",
		"description": "desc",
		"path":        "/new",
	})
	if res.IsError {
		t.Fatalf("IsError = true: %s", toolText(t, res))
	}

	var out mutationOutput
	if err := json.Unmarshal([]byte(toolText(t, res)), &out); err != nil {
		t.Fatalf("decode output: %v", err)
	}
	if !out.Succeeded || out.Message != "Page created" {
		t.Errorf("output = %+v", out)
	}

	req := fake.lastContaining(t, "mutation CreatePage")
	want := map[string]any{
		"editor":      "markdown",
		"isPublished": true,
		"isPrivate":   false,
		"locale":      "en",
	}
	for key, value := range want {
		if got := req.Variables[key]; got != value {
			t.Errorf("variables[%s] = %v, want %v", key, got, value)
		}
	}
	tags, ok := req.Variables["tags"].([]any)
	if !ok || len(tags) != 0 {
		t.Errorf("variables[tags] = %v, want []", req.Variables["tags"])
	}
}

func TestCreatePageFailure(t *testing.T) {
	cs, _ := newTestSession(t, true)

	res := callTool(t, cs, "create_page", map[string]any{
		"title":       "fail",
		"content":     "body",
		"description": "desc",
		"path":        "/new",
	})
	if !res.IsError {
		t.Fatal("IsError = false, want true")
	}
	text := toolText(t, res)
	if !strings.Contains(text, "failed to create page") || !strings.Contains(text, "Nope") || !strings.Contains(text, "6001") {
		t.Errorf("text = %q", text)
	}
}

func TestEditPageDefaults(t *testing.T) {
	cs, fake := newTestSession(t, true)

	res := callTool(t, cs, "edit_page", map[string]any{
		"id":          7,
		"title":       "Updated",
		"content":     "body",
		"description": "desc",
		"path":        "/start",
	})
	if res.IsError {
		t.Fatalf("IsError = true: %s", toolText(t, res))
	}

	var out mutationOutput
	if err := json.Unmarshal([]byte(toolText(t, res)), &out); err != nil {
		t.Fatalf("decode output: %v", err)
	}
	if !out.Succeeded || out.Message != "Page updated" {
		t.Errorf("output = %+v", out)
	}

	req := fake.lastContaining(t, "mutation UpdatePage")
	if got := req.Variables["id"]; got != float64(7) {
		t.Errorf("variables[id] = %v", got)
	}
	if got := req.Variables["editor"]; got != "markdown" {
		t.Errorf("variables[editor] = %v", got)
	}
}

func TestEditPageNotFound(t *testing.T) {
	cs, _ := newTestSession(t, true)

	res := callTool(t, cs, "edit_page", map[string]any{
		"id":          404,
		"title":       "Updated",
		"content":     "body",
		"description": "desc",
		"path":        "/start",
	})
	if !res.IsError {
		t.Fatal("IsError = false, want true")
	}
	text := toolText(t, res)
	if !strings.Contains(text, "failed to update page") || !strings.Contains(text, "Page not found") {
		t.Errorf("text = %q", text)
	}
}

func TestEditToolsHiddenWithoutEditMode(t *testing.T) {
	cs, _ := newTestSession(t, false)

	_, err := cs.CallTool(context.Background(), &mcp.CallToolParams{
		Name:      "create_page",
		Arguments: map[string]any{"title": "x", "content": "", "description": "", "path": "/x"},
	})
	if err == nil {
		t.Fatal("CallTool(create_page) error = nil, want tool not found")
	}
}

func TestToolOutputIsJSON(t *testing.T) {
	cs, _ := newTestSession(t, false)

	res := callTool(t, cs, "get_all_pages", nil)
	var decoded any
	if err := json.Unmarshal([]byte(toolText(t, res)), &decoded); err != nil {
		t.Fatalf("output is not JSON: %v", err)
	}
}