package handler

import (
	"bytes"
	"context"
	"encoding/json"
	"net/http"
	"net/http/httptest"
	"testing"
	"time"

	"github.com/gin-gonic/gin"
	"gorm.io/driver/sqlite"
	"gorm.io/gorm"

	"github.com/dhao2001/mygo/internal/middleware"
	"github.com/dhao2001/mygo/internal/model"
	"github.com/dhao2001/mygo/internal/repository"
	"github.com/dhao2001/mygo/internal/service"
)

func setupAdminRouter(t *testing.T) (*gin.Engine, repository.UserRepository) {
	t.Helper()

	db, err := gorm.Open(sqlite.Open(":memory:"), &gorm.Config{})
	if err != nil {
		t.Fatalf("open db: %v", err)
	}
	if err := db.AutoMigrate(&model.User{}, &model.Session{}, &model.Credential{}); err != nil {
		t.Fatalf("migrate: %v", err)
	}

	secret := []byte("test-secret")
	userRepo := repository.NewUserRepository(db)
	authService := service.NewAuthService(
		userRepo,
		repository.NewSessionRepository(db),
		repository.NewCredentialRepository(db),
		secret,
		15*time.Minute,
		7*24*time.Hour,
	)

	authHandler := NewAuthHandler(authService)
	adminHandler := NewAdminHandler(userRepo)

	gin.SetMode(gin.TestMode)
	r := gin.New()

	auth := r.Group("/api/v1/auth")
	{
		auth.POST("/register", authHandler.Register)
		auth.POST("/login", authHandler.Login)
	}

	admin := r.Group("/api/v1/admin")
	admin.Use(middleware.AuthRequired(secret))
	admin.Use(middleware.AdminRequired(userRepo))
	{
		admin.GET("/users", adminHandler.ListUsers)
		admin.GET("/users/:id", adminHandler.GetUser)
		admin.DELETE("/users/:id", adminHandler.DeleteUser)
	}

	return r, userRepo
}

// registerHelper creates a user via the HTTP endpoint and returns the user ID.
func registerHelper(t *testing.T, r *gin.Engine, username, email, password string) string {
	t.Helper()

	body, _ := json.Marshal(gin.H{
		"username": username,
		"email":    email,
		"password": password,
	})
	req := httptest.NewRequest(http.MethodPost, "/api/v1/auth/register", bytes.NewReader(body))
	req.Header.Set("Content-Type", "application/json")
	rec := httptest.NewRecorder()
	r.ServeHTTP(rec, req)

	if rec.Code != http.StatusCreated {
		t.Fatalf("register %s: status = %d, body = %s", username, rec.Code, rec.Body.String())
	}

	var user model.User
	if err := json.Unmarshal(rec.Body.Bytes(), &user); err != nil {
		t.Fatalf("unmarshal register response: %v", err)
	}
	return user.ID
}

// loginHelper logs in a user and returns the access token.
func loginHelper(t *testing.T, r *gin.Engine, email, password string) string {
	t.Helper()

	body, _ := json.Marshal(gin.H{"email": email, "password": password})
	req := httptest.NewRequest(http.MethodPost, "/api/v1/auth/login", bytes.NewReader(body))
	req.Header.Set("Content-Type", "application/json")
	rec := httptest.NewRecorder()
	r.ServeHTTP(rec, req)

	if rec.Code != http.StatusOK {
		t.Fatalf("login %s: status = %d, body = %s", email, rec.Code, rec.Body.String())
	}

	var pair service.TokenPair
	if err := json.Unmarshal(rec.Body.Bytes(), &pair); err != nil {
		t.Fatalf("unmarshal login response: %v", err)
	}
	return pair.AccessToken
}

// makeAdminHelper promotes a user to admin in the database.
func makeAdminHelper(t *testing.T, userRepo repository.UserRepository, userID string) {
	t.Helper()

	user, err := userRepo.FindByID(context.Background(), userID)
	if err != nil {
		t.Fatalf("find user %s: %v", userID, err)
	}
	user.IsAdmin = true
	if err := userRepo.Update(context.Background(), user); err != nil {
		t.Fatalf("update user: %v", err)
	}
}

func TestAdminDeleteUser(t *testing.T) {
	r, userRepo := setupAdminRouter(t)

	adminID := registerHelper(t, r, "admin", "admin@example.com", "adminpass123")
	makeAdminHelper(t, userRepo, adminID)

	userID := registerHelper(t, r, "bob", "bob@example.com", "bobpass123")

	adminToken := loginHelper(t, r, "admin@example.com", "adminpass123")

	// Delete regular user as admin
	req := httptest.NewRequest(http.MethodDelete, "/api/v1/admin/users/"+userID, nil)
	req.Header.Set("Authorization", "Bearer "+adminToken)
	rec := httptest.NewRecorder()
	r.ServeHTTP(rec, req)

	if rec.Code != http.StatusNoContent {
		t.Errorf("delete: status = %d, want %d; body = %s", rec.Code, http.StatusNoContent, rec.Body.String())
	}

	// Verify regular user cannot login (soft-deleted)
	loginBody, _ := json.Marshal(gin.H{"email": "bob@example.com", "password": "bobpass123"})
	req = httptest.NewRequest(http.MethodPost, "/api/v1/auth/login", bytes.NewReader(loginBody))
	req.Header.Set("Content-Type", "application/json")
	rec = httptest.NewRecorder()
	r.ServeHTTP(rec, req)

	if rec.Code != http.StatusUnauthorized {
		t.Errorf("login after soft-delete: status = %d, want %d; body = %s", rec.Code, http.StatusUnauthorized, rec.Body.String())
	}
}

func TestAdminDeleteUserForbidden(t *testing.T) {
	r, userRepo := setupAdminRouter(t)

	adminID := registerHelper(t, r, "admin", "admin@example.com", "adminpass123")
	makeAdminHelper(t, userRepo, adminID)

	userID := registerHelper(t, r, "bob", "bob@example.com", "bobpass123")

	// Login as regular user (non-admin)
	userToken := loginHelper(t, r, "bob@example.com", "bobpass123")

	// Attempt to delete as non-admin
	req := httptest.NewRequest(http.MethodDelete, "/api/v1/admin/users/"+userID, nil)
	req.Header.Set("Authorization", "Bearer "+userToken)
	rec := httptest.NewRecorder()
	r.ServeHTTP(rec, req)

	if rec.Code != http.StatusForbidden {
		t.Errorf("status = %d, want %d; body = %s", rec.Code, http.StatusForbidden, rec.Body.String())
	}
}

func TestAdminDeleteUserUnauthorized(t *testing.T) {
	r, _ := setupAdminRouter(t)

	req := httptest.NewRequest(http.MethodDelete, "/api/v1/admin/users/some-id", nil)
	rec := httptest.NewRecorder()
	r.ServeHTTP(rec, req)

	if rec.Code != http.StatusUnauthorized {
		t.Errorf("status = %d, want %d; body = %s", rec.Code, http.StatusUnauthorized, rec.Body.String())
	}
}

func TestAdminGetUser(t *testing.T) {
	r, userRepo := setupAdminRouter(t)

	adminID := registerHelper(t, r, "admin", "admin@example.com", "adminpass123")
	makeAdminHelper(t, userRepo, adminID)

	userID := registerHelper(t, r, "bob", "bob@example.com", "bobpass123")

	adminToken := loginHelper(t, r, "admin@example.com", "adminpass123")

	req := httptest.NewRequest(http.MethodGet, "/api/v1/admin/users/"+userID, nil)
	req.Header.Set("Authorization", "Bearer "+adminToken)
	rec := httptest.NewRecorder()
	r.ServeHTTP(rec, req)

	if rec.Code != http.StatusOK {
		t.Fatalf("get user: status = %d, want %d; body = %s", rec.Code, http.StatusOK, rec.Body.String())
	}

	var resp struct {
		ID       string `json:"id"`
		Username string `json:"username"`
		Email    string `json:"email"`
		IsAdmin  bool   `json:"is_admin"`
		Status   string `json:"status"`
	}
	if err := json.Unmarshal(rec.Body.Bytes(), &resp); err != nil {
		t.Fatalf("unmarshal: %v", err)
	}

	if resp.Username != "bob" {
		t.Errorf("username = %q, want %q", resp.Username, "bob")
	}
	if resp.Status != model.StatusActive {
		t.Errorf("status = %q, want %q", resp.Status, model.StatusActive)
	}
}

func TestAdminGetDeletedUser(t *testing.T) {
	r, userRepo := setupAdminRouter(t)

	adminID := registerHelper(t, r, "admin", "admin@example.com", "adminpass123")
	makeAdminHelper(t, userRepo, adminID)

	userID := registerHelper(t, r, "bob", "bob@example.com", "bobpass123")

	// Soft-delete regular user directly via repo
	if err := userRepo.Delete(context.Background(), userID); err != nil {
		t.Fatalf("soft-delete user: %v", err)
	}

	adminToken := loginHelper(t, r, "admin@example.com", "adminpass123")

	req := httptest.NewRequest(http.MethodGet, "/api/v1/admin/users/"+userID, nil)
	req.Header.Set("Authorization", "Bearer "+adminToken)
	rec := httptest.NewRecorder()
	r.ServeHTTP(rec, req)

	if rec.Code != http.StatusOK {
		t.Fatalf("get deleted user: status = %d, want %d; body = %s", rec.Code, http.StatusOK, rec.Body.String())
	}

	var resp struct {
		Status string `json:"status"`
	}
	if err := json.Unmarshal(rec.Body.Bytes(), &resp); err != nil {
		t.Fatalf("unmarshal: %v", err)
	}

	if resp.Status != model.StatusAdminDeleted {
		t.Errorf("status = %q, want %q", resp.Status, model.StatusAdminDeleted)
	}
}

func TestAdminListIncludesDeleted(t *testing.T) {
	r, userRepo := setupAdminRouter(t)

	adminID := registerHelper(t, r, "admin", "admin@example.com", "adminpass123")
	makeAdminHelper(t, userRepo, adminID)

	// Create 2 regular users
	_ = registerHelper(t, r, "alice", "alice@example.com", "alicepass123")
	bobID := registerHelper(t, r, "bob", "bob@example.com", "bobpass123")

	// Soft-delete bob
	if err := userRepo.Delete(context.Background(), bobID); err != nil {
		t.Fatalf("soft-delete user: %v", err)
	}

	adminToken := loginHelper(t, r, "admin@example.com", "adminpass123")

	req := httptest.NewRequest(http.MethodGet, "/api/v1/admin/users", nil)
	req.Header.Set("Authorization", "Bearer "+adminToken)
	rec := httptest.NewRecorder()
	r.ServeHTTP(rec, req)

	if rec.Code != http.StatusOK {
		t.Fatalf("list users: status = %d, want %d; body = %s", rec.Code, http.StatusOK, rec.Body.String())
	}

	var resp struct {
		Users []struct {
			ID     string `json:"id"`
			Status string `json:"status"`
		} `json:"users"`
		Total int64 `json:"total"`
	}
	if err := json.Unmarshal(rec.Body.Bytes(), &resp); err != nil {
		t.Fatalf("unmarshal: %v", err)
	}

	// Total should be 3: admin + alice (active) + bob (soft-deleted)
	if resp.Total != 3 {
		t.Errorf("total = %d, want %d", resp.Total, 3)
	}

	// Verify both active and soft-deleted users appear
	foundAlice := false
	foundBob := false
	for _, u := range resp.Users {
		switch u.Status {
		case model.StatusActive:
			// alice or admin
			foundAlice = true
		case model.StatusAdminDeleted:
			if u.ID == bobID {
				foundBob = true
			}
		}
	}
	if !foundAlice {
		t.Error("active user not found in list")
	}
	if !foundBob {
		t.Error("soft-deleted user not found in list")
	}
}