package wikijs

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

func newTestClient(t *testing.T, handler http.HandlerFunc) *Client {
	t.Helper()
	srv := httptest.NewServer(handler)
	t.Cleanup(srv.Close)

	client, err := New(srv.URL, "test-key", WithUserAgent("wikijs-mcp/test"))
	if err != nil {
		t.Fatalf("New() error = %v", err)
	}
	return client
}

func decodeRequest(t *testing.T, r *http.Request) graphqlRequest {
	t.Helper()
	var req graphqlRequest
	if err := json.NewDecoder(r.Body).Decode(&req); err != nil {
		t.Errorf("decode request: %v", err)
	}
	return req
}

func writeJSON(t *testing.T, w http.ResponseWriter, status int, body string) {
	t.Helper()
	w.Header().Set("Content-Type", "application/json")
	w.WriteHeader(status)
	if _, err := w.Write([]byte(body)); err != nil {
		t.Errorf("write response: %v", err)
	}
}

func TestNewNormalizesURL(t *testing.T) {
	tests := []struct {
		base         string
		wantBase     string
		wantEndpoint string
	}{
		{base: "https://wiki.example.com", wantBase: "https://wiki.example.com", wantEndpoint: "https://wiki.example.com/graphql"},
		{base: "https://wiki.example.com/", wantBase: "https://wiki.example.com", wantEndpoint: "https://wiki.example.com/graphql"},
		{base: "https://wiki.example.com/graphql", wantBase: "https://wiki.example.com", wantEndpoint: "https://wiki.example.com/graphql"},
		{base: "https://wiki.example.com/graphql/", wantBase: "https://wiki.example.com", wantEndpoint: "https://wiki.example.com/graphql"},
		{base: "https://wiki.example.com/wiki", wantBase: "https://wiki.example.com/wiki", wantEndpoint: "https://wiki.example.com/wiki/graphql"},
	}
	for _, tt := range tests {
		t.Run(tt.base, func(t *testing.T) {
			c, err := New(tt.base, "key")
			if err != nil {
				t.Fatalf("New() error = %v", err)
			}
			if c.baseURL != tt.wantBase {
				t.Errorf("baseURL = %q, want %q", c.baseURL, tt.wantBase)
			}
			if c.endpoint != tt.wantEndpoint {
				t.Errorf("endpoint = %q, want %q", c.endpoint, tt.wantEndpoint)
			}
		})
	}
}

func TestNewRejectsInvalidURL(t *testing.T) {
	for _, raw := range []string{"", "wiki.example.com", "ftp://wiki.example.com", "/relative", "https://wiki.example.com/?a=1", "https://wiki.example.com/#x"} {
		if _, err := New(raw, "key"); err == nil {
			t.Errorf("New(%q) error = nil, want error", raw)
		}
	}
}

func TestPageByID(t *testing.T) {
	client := newTestClient(t, func(w http.ResponseWriter, r *http.Request) {
		if got, want := r.Header.Get("Authorization"), "Bearer test-key"; got != want {
			t.Errorf("Authorization = %q, want %q", got, want)
		}
		if got, want := r.Header.Get("User-Agent"), "wikijs-mcp/test"; got != want {
			t.Errorf("User-Agent = %q, want %q", got, want)
		}
		if got, want := r.Header.Get("Content-Type"), "application/json"; got != want {
			t.Errorf("Content-Type = %q, want %q", got, want)
		}
		req := decodeRequest(t, r)
		if !strings.Contains(req.Query, "single(id: $id)") {
			t.Errorf("query does not contain single query: %s", req.Query)
		}
		if got := req.Variables["id"]; got != float64(42) {
			t.Errorf("variables[id] = %v, want 42", got)
		}
		writeJSON(t, w, http.StatusOK, `{"data":{"pages":{"single":{
			"id":42,"path":"/dev/go","title":"Go","description":"desc",
			"tags":[{"tag":"go","title":"Go"}],"content":"body",
			"createdAt":"2025-01-01T00:00:00Z","updatedAt":"2025-01-02T00:00:00Z",
			"locale":"de"}}}}`)
	})

	page, err := client.PageByID(context.Background(), 42)
	if err != nil {
		t.Fatalf("PageByID() error = %v", err)
	}
	if page == nil {
		t.Fatal("PageByID() = nil, want page")
	}
	if page.ID != 42 || page.Title != "Go" {
		t.Errorf("page = %+v", page)
	}
	if got, want := page.URL, client.baseURL+"/de/dev/go"; got != want {
		t.Errorf("URL = %q, want %q", got, want)
	}
	if len(page.Tags) != 1 || page.Tags[0].Tag != "go" {
		t.Errorf("Tags = %+v", page.Tags)
	}
}

func TestPageByIDEnglishHasNoLocalePrefix(t *testing.T) {
	client := newTestClient(t, func(w http.ResponseWriter, r *http.Request) {
		writeJSON(t, w, http.StatusOK, `{"data":{"pages":{"single":{
			"id":1,"path":"/start","title":"Start","description":"",
			"tags":null,"content":"","createdAt":"","updatedAt":"","locale":"en"}}}}`)
	})

	page, err := client.PageByID(context.Background(), 1)
	if err != nil {
		t.Fatalf("PageByID() error = %v", err)
	}
	if got, want := page.URL, client.baseURL+"/start"; got != want {
		t.Errorf("URL = %q, want %q", got, want)
	}
	if page.Tags == nil {
		t.Error("Tags = nil, want empty slice")
	}
}

func TestPageByIDNotFound(t *testing.T) {
	client := newTestClient(t, func(w http.ResponseWriter, r *http.Request) {
		writeJSON(t, w, http.StatusOK, `{"data":{"pages":{"single":null}}}`)
	})

	page, err := client.PageByID(context.Background(), 99)
	if err != nil {
		t.Fatalf("PageByID() error = %v", err)
	}
	if page != nil {
		t.Errorf("PageByID() = %+v, want nil", page)
	}
}

func TestPageByPath(t *testing.T) {
	client := newTestClient(t, func(w http.ResponseWriter, r *http.Request) {
		req := decodeRequest(t, r)
		if !strings.Contains(req.Query, "singleByPath") {
			t.Errorf("query = %s", req.Query)
		}
		if got := req.Variables["path"]; got != "/start" {
			t.Errorf("variables[path] = %v", got)
		}
		if got := req.Variables["locale"]; got != "de-DE" {
			t.Errorf("variables[locale] = %v", got)
		}
		writeJSON(t, w, http.StatusOK, `{"data":{"pages":{"singleByPath":{
			"id":7,"path":"/start","title":"Start","description":"desc",
			"tags":[],"content":"body","createdAt":"c","updatedAt":"u","locale":"de-DE"}}}}`)
	})

	page, err := client.PageByPath(context.Background(), "/start", "de-DE")
	if err != nil {
		t.Fatalf("PageByPath() error = %v", err)
	}
	if got, want := page.URL, client.baseURL+"/de-DE/start"; got != want {
		t.Errorf("URL = %q, want %q", got, want)
	}
}

func TestSearchPages(t *testing.T) {
	client := newTestClient(t, func(w http.ResponseWriter, r *http.Request) {
		req := decodeRequest(t, r)
		if got := req.Variables["query"]; got != "mcp" {
			t.Errorf("variables[query] = %v", got)
		}
		if got := req.Variables["path"]; got != "/dev" {
			t.Errorf("variables[path] = %v", got)
		}
		if _, ok := req.Variables["locale"]; ok {
			t.Errorf("variables[locale] = %v, want omitted", req.Variables["locale"])
		}
		writeJSON(t, w, http.StatusOK, `{"data":{"pages":{"search":{
			"results":[
				{"title":"A","description":"a","path":"/a","locale":"en"},
				null,
				{"title":"B","description":"b","path":"/b","locale":"de"}
			],
			"suggestions":["s1"],"totalHits":3}}}}`)
	})

	res, err := client.SearchPages(context.Background(), "mcp", "/dev", "")
	if err != nil {
		t.Fatalf("SearchPages() error = %v", err)
	}
	if got, want := res.TotalHits, 3; got != want {
		t.Errorf("TotalHits = %d, want %d", got, want)
	}
	if len(res.Results) != 2 {
		t.Fatalf("Results = %d, want 2", len(res.Results))
	}
	if got, want := res.Results[0].URL, client.baseURL+"/a"; got != want {
		t.Errorf("URL = %q, want %q", got, want)
	}
	if got, want := res.Results[1].URL, client.baseURL+"/de/b"; got != want {
		t.Errorf("URL = %q, want %q", got, want)
	}
	if len(res.Suggestions) != 1 || res.Suggestions[0] != "s1" {
		t.Errorf("Suggestions = %v", res.Suggestions)
	}
}

func TestSearchPagesEmpty(t *testing.T) {
	client := newTestClient(t, func(w http.ResponseWriter, r *http.Request) {
		writeJSON(t, w, http.StatusOK, `{"data":{"pages":{"search":null}}}`)
	})

	res, err := client.SearchPages(context.Background(), "nothing", "", "")
	if err != nil {
		t.Fatalf("SearchPages() error = %v", err)
	}
	if res.Results == nil || res.Suggestions == nil {
		t.Errorf("empty slices must not be nil: %+v", res)
	}
	if res.TotalHits != 0 {
		t.Errorf("TotalHits = %d, want 0", res.TotalHits)
	}
}

func TestListPages(t *testing.T) {
	client := newTestClient(t, func(w http.ResponseWriter, r *http.Request) {
		req := decodeRequest(t, r)
		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)
		}
		tags, ok := req.Variables["tags"].([]any)
		if !ok || len(tags) != 2 || tags[0] != "go" {
			t.Errorf("variables[tags] = %v", req.Variables["tags"])
		}
		writeJSON(t, w, http.StatusOK, `{"data":{"pages":{"list":[
			{"id":1,"path":"/a","locale":"de","title":"A","description":"a",
			 "createdAt":"c","updatedAt":"u","tags":["go"]},
			null,
			{"id":2,"path":"/b","locale":"en","title":"B","description":"b",
			 "createdAt":"c","updatedAt":"u","tags":null}
		]}}}`)
	})

	limit := 10
	pages, err := client.ListPages(context.Background(), ListOptions{
		Limit:  &limit,
		Locale: "de",
		Tags:   []string{"go", "mcp"},
	})
	if err != nil {
		t.Fatalf("ListPages() error = %v", err)
	}
	if len(pages) != 2 {
		t.Fatalf("ListPages() returned %d pages, want 2", len(pages))
	}
	if got, want := pages[0].URL, client.baseURL+"/de/a"; got != want {
		t.Errorf("URL = %q, want %q", got, want)
	}
	if pages[1].Tags == nil {
		t.Error("Tags = nil, want empty slice")
	}
}

func TestListPagesOmitsEmptyFilters(t *testing.T) {
	client := newTestClient(t, func(w http.ResponseWriter, r *http.Request) {
		req := decodeRequest(t, r)
		for _, key := range []string{"limit", "locale", "tags"} {
			if _, ok := req.Variables[key]; ok {
				t.Errorf("variables[%s] present, want omitted", key)
			}
		}
		writeJSON(t, w, http.StatusOK, `{"data":{"pages":{"list":[]}}}`)
	})

	if _, err := client.ListPages(context.Background(), ListOptions{}); err != nil {
		t.Fatalf("ListPages() error = %v", err)
	}
}

func TestCreatePage(t *testing.T) {
	client := newTestClient(t, func(w http.ResponseWriter, r *http.Request) {
		req := decodeRequest(t, r)
		if !strings.Contains(req.Query, "mutation CreatePage") {
			t.Errorf("query = %s", req.Query)
		}
		if got := req.Variables["tags"].([]any); len(got) != 1 || got[0] != "go" {
			t.Errorf("variables[tags] = %v", req.Variables["tags"])
		}
		if got := req.Variables["isPublished"]; got != true {
			t.Errorf("variables[isPublished] = %v", got)
		}
		writeJSON(t, w, http.StatusOK, `{"data":{"pages":{"create":{"responseResult":{
			"succeeded":true,"errorCode":0,"slug":"new-page","message":"Page created"}}}}}`)
	})

	res, err := client.CreatePage(context.Background(), CreatePageInput{
		Title:       "New",
		Content:     "body",
		Description: "desc",
		Path:        "new-page",
		Editor:      "markdown",
		IsPublished: true,
		Locale:      "en",
		Tags:        []string{"go"},
	})
	if err != nil {
		t.Fatalf("CreatePage() error = %v", err)
	}
	if !res.Succeeded || res.Message != "Page created" || res.Slug != "new-page" {
		t.Errorf("result = %+v", res)
	}
}

func TestUpdatePageFailureIsReturned(t *testing.T) {
	client := newTestClient(t, func(w http.ResponseWriter, r *http.Request) {
		writeJSON(t, w, http.StatusOK, `{"data":{"pages":{"update":{"responseResult":{
			"succeeded":false,"errorCode":6001,"slug":"","message":"Page not found"}}}}}`)
	})

	res, err := client.UpdatePage(context.Background(), UpdatePageInput{ID: 1})
	if err != nil {
		t.Fatalf("UpdatePage() error = %v", err)
	}
	if res.Succeeded {
		t.Error("Succeeded = true, want false")
	}
	if res.ErrorCode != 6001 || res.Message != "Page not found" {
		t.Errorf("result = %+v", res)
	}
}

func TestGraphQLErrors(t *testing.T) {
	client := newTestClient(t, func(w http.ResponseWriter, r *http.Request) {
		writeJSON(t, w, http.StatusOK, `{"errors":[{"message":"Unauthorized"},{"message":"Forbidden"}]}`)
	})

	_, err := client.PageByID(context.Background(), 1)
	if err == nil {
		t.Fatal("PageByID() error = nil, want error")
	}
	var apiErr *APIError
	if !errors.As(err, &apiErr) {
		t.Fatalf("error type = %T, want *APIError", err)
	}
	if got := apiErr.Error(); !strings.Contains(got, "Unauthorized") || !strings.Contains(got, "Forbidden") {
		t.Errorf("error = %q", got)
	}
}

func TestHTTPError(t *testing.T) {
	client := newTestClient(t, func(w http.ResponseWriter, r *http.Request) {
		http.Error(w, "server exploded", http.StatusInternalServerError)
	})

	_, err := client.PageByID(context.Background(), 1)
	if err == nil {
		t.Fatal("PageByID() error = nil, want error")
	}
	var apiErr *APIError
	if !errors.As(err, &apiErr) {
		t.Fatalf("error type = %T, want *APIError", err)
	}
	if apiErr.Status != http.StatusInternalServerError {
		t.Errorf("Status = %d, want 500", apiErr.Status)
	}
	if !strings.Contains(err.Error(), "server exploded") {
		t.Errorf("error = %q", err)
	}
}

func TestMissingData(t *testing.T) {
	client := newTestClient(t, func(w http.ResponseWriter, r *http.Request) {
		writeJSON(t, w, http.StatusOK, `{"data":null}`)
	})

	_, err := client.PageByID(context.Background(), 1)
	if err == nil {
		t.Fatal("PageByID() error = nil, want error")
	}
}

func TestContextCancellation(t *testing.T) {
	client := newTestClient(t, func(w http.ResponseWriter, r *http.Request) {
		t.Error("handler must not be called")
	})
	ctx, cancel := context.WithCancel(context.Background())
	cancel()

	if _, err := client.PageByID(ctx, 1); err == nil {
		t.Fatal("PageByID() error = nil, want context error")
	}
}