package main

import (
	"bytes"
	"context"
	"encoding/json"
	"errors"
	"fmt"
	"io"
	"net/http"
	"net/http/httptest"
	"strconv"
	"strings"
	"sync"
	"testing"

	"git.yuntuo.hk/k2safe/go-omni"
	"git.yuntuo.hk/k2safe/go-omni/auth"
	"git.yuntuo.hk/k2safe/go-omni/examples/reference/model"
	"git.yuntuo.hk/k2safe/go-omni/examples/reference/repository"
	"git.yuntuo.hk/k2safe/go-omni/httpx"
	"git.yuntuo.hk/k2safe/go-omni/logx"
	ginrouter "git.yuntuo.hk/k2safe/go-omni/transport/gin"
	netrouter "git.yuntuo.hk/k2safe/go-omni/transport/nethttp"
)

type envelope struct {
	Code      string          `json:"code"`
	Message   string          `json:"message"`
	Data      json.RawMessage `json:"data"`
	RequestID string          `json:"requestId"`
}

func testApp() *omni.App {
	return newApp(repository.NewMemoryUsers(), testLogger(io.Discard), omni.WithMode("test"))
}

func testLogger(writer io.Writer) *logx.Logger {
	logger, err := logx.New(logx.Config{Format: "json", Writer: writer})
	if err != nil {
		panic(err)
	}
	return logger
}

func request(t *testing.T, app http.Handler, method, path, body string, status int, code string) envelope {
	return requestWithAuthorization(t, app, method, path, body, "", status, code)
}

func requestWithAuthorization(t *testing.T, app http.Handler, method, path, body, authorization string, status int, code string) envelope {
	t.Helper()
	req := httptest.NewRequest(method, path, strings.NewReader(body))
	req.Header.Set("Content-Type", "application/json")
	req.Header.Set("X-Request-ID", "reference-test")
	if authorization != "" {
		req.Header.Set("Authorization", authorization)
	}
	w := httptest.NewRecorder()
	app.ServeHTTP(w, req)
	if w.Code != status {
		t.Fatalf("%s %s: want status %d, got %d: %s", method, path, status, w.Code, w.Body.String())
	}
	if w.Header().Get("X-Request-ID") != "reference-test" {
		t.Fatalf("request ID header was not propagated: %v", w.Header())
	}
	if status == http.StatusNoContent {
		if w.Body.Len() != 0 {
			t.Fatalf("204 must have no body: %s", w.Body.String())
		}
		return envelope{}
	}
	if !strings.HasPrefix(w.Header().Get("Content-Type"), "application/json") {
		t.Fatalf("expected JSON content type: %v", w.Header())
	}
	var result envelope
	if err := json.Unmarshal(w.Body.Bytes(), &result); err != nil {
		t.Fatalf("invalid JSON response: %v: %s", err, w.Body.String())
	}
	if result.Code != code || result.RequestID != "reference-test" {
		t.Fatalf("unexpected envelope: %+v", result)
	}
	return result
}

func TestProtectedWriteRoutes(t *testing.T) {
	app := newProtectedApp(
		repository.NewMemoryUsers(),
		testLogger(io.Discard),
		auth.StaticAuthenticator{"user-token": {UserID: "user-1", Roles: []string{"user"}}},
		omni.WithMode("test"),
	)
	request(t, app, "POST", "/api/v1/users", `{"name":"Alice","email":"alice@example.com"}`, 401, "UNAUTHENTICATED")
	created := dataAs[model.User](t, requestWithAuthorization(t, app, "POST", "/api/v1/users", `{"name":"Alice","email":"alice@example.com"}`, "Bearer user-token", 201, "CREATED"))
	path := "/api/v1/users/" + strconv.FormatInt(created.ID, 10)
	requestWithAuthorization(t, app, "DELETE", path, "", "Bearer user-token", 403, "FORBIDDEN")
	requestWithAuthorization(t, app, "PUT", path, `{"name":"Alice Updated","email":"alice.updated@example.com"}`, "Bearer user-token", 200, "OK")
}

func dataAs[T any](t *testing.T, value envelope) T {
	t.Helper()
	var data T
	if err := json.Unmarshal(value.Data, &data); err != nil {
		t.Fatalf("decode data: %v", err)
	}
	return data
}

func TestUserCRUD(t *testing.T) {
	for _, adapter := range []struct {
		name      string
		newRouter func() httpx.Router
	}{
		{"gin", func() httpx.Router { return ginrouter.New("test") }},
		{"nethttp", func() httpx.Router { return netrouter.New() }},
	} {
		t.Run(adapter.name, func(t *testing.T) {
			application := omni.NewWithRouter(adapter.newRouter())
			registerRoutes(application, repository.NewMemoryUsers(), testLogger(io.Discard), nil, nil)
			checkUserCRUD(t, application)
		})
	}
}

func checkUserCRUD(t *testing.T, app *omni.App) {
	t.Helper()
	health := dataAs[map[string]string](t, request(t, app, "GET", "/health", "", 200, "OK"))
	if health["status"] != "ok" {
		t.Fatalf("unexpected health: %v", health)
	}
	empty := dataAs[model.UserPage](t, request(t, app, "GET", "/api/v1/users", "", 200, "OK"))
	if empty.Items == nil || len(empty.Items) != 0 || empty.Total != 0 || empty.Page != 1 || empty.PageSize != 20 {
		t.Fatalf("unexpected empty page: %+v", empty)
	}

	alice := dataAs[model.User](t, request(t, app, "POST", "/api/v1/users", `{"name":" Alice ","email":"ALICE@example.com"}`, 201, "CREATED"))
	if alice.ID <= 0 || alice.Name != "Alice" || alice.Email != "alice@example.com" || alice.CreatedAt.IsZero() || !alice.CreatedAt.Equal(alice.UpdatedAt) {
		t.Fatalf("unexpected created user: %+v", alice)
	}
	path := "/api/v1/users/" + strconv.FormatInt(alice.ID, 10)
	got := dataAs[model.User](t, request(t, app, "GET", path, "", 200, "OK"))
	if got != alice {
		t.Fatalf("get did not preserve user: %+v", got)
	}
	request(t, app, "POST", "/api/v1/users", `{"name":"Duplicate","email":"Alice@EXAMPLE.com"}`, 409, "EMAIL_TAKEN")

	bob := dataAs[model.User](t, request(t, app, "POST", "/api/v1/users", `{"name":"Bob","email":"bob@example.com"}`, 201, "CREATED"))
	page := dataAs[model.UserPage](t, request(t, app, "GET", "/api/v1/users?page=2&pageSize=1", "", 200, "OK"))
	if page.Total != 2 || page.Page != 2 || page.PageSize != 1 || len(page.Items) != 1 || page.Items[0] != bob {
		t.Fatalf("unexpected page: %+v", page)
	}
	// An extreme page must return an empty list without an integer overflow.
	hugePage := strconv.Itoa(int(^uint(0) >> 1))
	outOfRange := dataAs[model.UserPage](t, request(t, app, "GET", "/api/v1/users?page="+hugePage+"&pageSize=100", "", 200, "OK"))
	if outOfRange.Items == nil || len(outOfRange.Items) != 0 || outOfRange.Total != 2 {
		t.Fatalf("unexpected out-of-range page: %+v", outOfRange)
	}

	// A conflicting update must not partially modify either user or email index.
	request(t, app, "PUT", path, `{"name":"Changed","email":"BOB@example.com"}`, 409, "EMAIL_TAKEN")
	unchanged := dataAs[model.User](t, request(t, app, "GET", path, "", 200, "OK"))
	if unchanged != alice {
		t.Fatalf("failed update changed data: %+v", unchanged)
	}
	updated := dataAs[model.User](t, request(t, app, "PUT", path, `{"name":"Alice Updated","email":"new@example.com"}`, 200, "OK"))
	if updated.ID != alice.ID || updated.Name != "Alice Updated" || updated.Email != "new@example.com" || !updated.CreatedAt.Equal(alice.CreatedAt) || updated.UpdatedAt.Before(alice.UpdatedAt) {
		t.Fatalf("unexpected update: %+v", updated)
	}
	// Retaining one's own email is allowed; the old email can be reused.
	request(t, app, "PUT", path, `{"name":"Alice Updated","email":"new@example.com"}`, 200, "OK")
	request(t, app, "POST", "/api/v1/users", `{"name":"Reused","email":"alice@example.com"}`, 201, "CREATED")
	request(t, app, "DELETE", path, "", 204, "")
	request(t, app, "GET", path, "", 404, "USER_NOT_FOUND")
	request(t, app, "DELETE", path, "", 404, "USER_NOT_FOUND")
	request(t, app, "POST", "/api/v1/users", `{"name":"Reused Again","email":"new@example.com"}`, 201, "CREATED")
}

func TestUserValidation(t *testing.T) {
	app := testApp()
	for _, test := range []struct {
		name, method, path, body, code string
	}{
		{"malformed JSON", "POST", "/api/v1/users", `{"name":`, "INVALID_BODY"},
		{"missing email", "POST", "/api/v1/users", `{"name":"Alice"}`, "INVALID_BODY"},
		{"invalid email", "POST", "/api/v1/users", `{"name":"Alice","email":"invalid"}`, "INVALID_BODY"},
		{"blank name", "POST", "/api/v1/users", `{"name":"  ","email":"alice@example.com"}`, "INVALID_USER"},
		{"negative ID", "GET", "/api/v1/users/-1", "", "INVALID_PATH"},
		{"zero ID", "DELETE", "/api/v1/users/0", "", "INVALID_PATH"},
		{"text ID", "PUT", "/api/v1/users/abc", `{}`, "INVALID_PATH"},
		{"overflow ID", "GET", "/api/v1/users/99999999999999999999999", "", "INVALID_PATH"},
		{"zero page", "GET", "/api/v1/users?page=0", "", "INVALID_QUERY"},
		{"negative page", "GET", "/api/v1/users?page=-1", "", "INVALID_QUERY"},
		{"text page", "GET", "/api/v1/users?page=abc", "", "INVALID_QUERY"},
		{"zero page size", "GET", "/api/v1/users?pageSize=0", "", "INVALID_QUERY"},
		{"large page size", "GET", "/api/v1/users?pageSize=101", "", "INVALID_QUERY"},
		{"incomplete replacement", "PUT", "/api/v1/users/1", `{"name":"Alice"}`, "INVALID_BODY"},
	} {
		t.Run(test.name, func(t *testing.T) {
			request(t, app, test.method, test.path, test.body, 400, test.code)
		})
	}
	request(t, app, "GET", "/api/v1/users/123", "", 404, "USER_NOT_FOUND")
	request(t, app, "PUT", "/api/v1/users/123", `{"name":"Alice","email":"alice@example.com"}`, 404, "USER_NOT_FOUND")
	page := dataAs[model.UserPage](t, request(t, app, "GET", "/api/v1/users", "", 200, "OK"))
	if page.Total != 0 {
		t.Fatalf("invalid requests mutated storage: %+v", page)
	}
}

type failingUsers struct {
	*repository.MemoryUsers
	err error
}

func (r failingUsers) Get(context.Context, int64) (model.User, error) {
	return model.User{}, r.err
}

func TestErrorTranslationAndRequestLogging(t *testing.T) {
	for _, test := range []struct {
		name, code string
		err        error
		status     int
	}{
		{"internal failure", "INTERNAL_ERROR", errors.New("private database diagnostic"), 500},
		{"wrapped domain error", "USER_NOT_FOUND", fmt.Errorf("lookup failed: %w", model.ErrUserNotFound), 404},
	} {
		t.Run(test.name, func(t *testing.T) {
			var logs bytes.Buffer
			app := newApp(failingUsers{repository.NewMemoryUsers(), test.err}, testLogger(&logs), omni.WithMode("test"))
			result := request(t, app, "GET", "/api/v1/users/1", "", test.status, test.code)
			if strings.Contains(result.Message, test.err.Error()) || len(result.Data) != 0 {
				t.Fatalf("internal error details leaked: %+v", result)
			}
			var logEntry map[string]any
			if err := json.Unmarshal(logs.Bytes(), &logEntry); err != nil {
				t.Fatalf("missing or invalid request log: %v: %s", err, logs.String())
			}
			if logEntry["requestId"] != "reference-test" || logEntry["path"] != "/api/v1/users/1" || !strings.Contains(fmt.Sprint(logEntry["error"]), test.err.Error()) {
				t.Fatalf("missing request/error context in log: %v", logEntry)
			}
		})
	}
}

func TestConcurrentEmailUniqueness(t *testing.T) {
	app := testApp()
	server := httptest.NewServer(app)
	defer server.Close()
	const count = 24
	results := make(chan int, count)
	errors := make(chan error, count)
	var workers sync.WaitGroup
	for i := 0; i < count; i++ {
		workers.Add(1)
		go func(i int) {
			defer workers.Done()
			email := "same@example.com"
			if i%2 == 0 {
				email = "SAME@example.com"
			}
			body := fmt.Sprintf(`{"name":"User %d","email":%q}`, i, email)
			response, err := server.Client().Post(server.URL+"/api/v1/users", "application/json", strings.NewReader(body))
			if err != nil {
				errors <- err
				return
			}
			io.Copy(io.Discard, response.Body)
			response.Body.Close()
			results <- response.StatusCode
		}(i)
	}
	workers.Wait()
	close(results)
	close(errors)
	for err := range errors {
		t.Errorf("request failed: %v", err)
	}
	created, conflicts := 0, 0
	for status := range results {
		switch status {
		case 201:
			created++
		case 409:
			conflicts++
		default:
			t.Errorf("unexpected status: %d", status)
		}
	}
	if created != 1 || conflicts != count-1 {
		t.Fatalf("want one create and %d conflicts, got %d creates and %d conflicts", count-1, created, conflicts)
	}
	page := dataAs[model.UserPage](t, request(t, app, "GET", "/api/v1/users", "", 200, "OK"))
	if page.Total != 1 {
		t.Fatalf("duplicate users persisted: %+v", page)
	}
}