package handlers

import (
	"bookmann/internal/database"
	"fmt"
	"net/http"
	"time"

	jwtgo "github.com/golang-jwt/jwt"
	"github.com/google/uuid"
	"github.com/jackc/pgx/v5/pgtype"
	"github.com/labstack/echo/v4"
	"golang.org/x/crypto/bcrypt"
)

type AuthHandler struct {
	db     *database.Queries
	jwtKey []byte
}

func NewAuthHandler(db *database.Queries, jwtSecret string) *AuthHandler {
	return &AuthHandler{
		db:     db,
		jwtKey: []byte(jwtSecret),
	}
}

type RegisterRequest struct {
	Email    string `form:"email" json:"email" validate:"required,email"`
	Username string `form:"username" json:"username" validate:"required,min=3,max=50"`
	Password string `form:"password" json:"password" validate:"required,min=6"`
}

type LoginRequest struct {
	Login    string `form:"login" json:"login" validate:"required"` // email or username
	Password string `form:"password" json:"password" validate:"required"`
}

type AuthResponse struct {
	Token string      `json:"token"`
	User  UserProfile `json:"user"`
}

type UserProfile struct {
	ID       string `json:"id"`
	Email    string `json:"email"`
	Username string `json:"username"`
}

// Register handles POST /api/auth/register
func (h *AuthHandler) Register(c echo.Context) error {
	// Try form data first (HTMX), then JSON (Bruno)
	email := c.FormValue("email")
	username := c.FormValue("username")
	password := c.FormValue("password")

	if email == "" || username == "" || password == "" {
		// Fallback to JSON binding
		req := RegisterRequest{}
		if err := c.Bind(&req); err != nil {
			if c.Request().Header.Get("HX-Request") == "true" {
				return c.HTML(http.StatusBadRequest, `<div class="text-red-500">Invalid request</div>`)
			}
			return c.JSON(http.StatusBadRequest, map[string]string{"error": "invalid request"})
		}
		if err := c.Validate(&req); err != nil {
			if c.Request().Header.Get("HX-Request") == "true" {
				return c.HTML(http.StatusBadRequest, `<div class="text-red-500">`+err.Error()+`</div>`)
			}
			return c.JSON(http.StatusBadRequest, map[string]string{"error": err.Error()})
		}
		email = req.Email
		username = req.Username
		password = req.Password
	}

	req := RegisterRequest{Email: email, Username: username, Password: password}
	if err := c.Validate(&req); err != nil {
		if c.Request().Header.Get("HX-Request") == "true" {
			return c.HTML(http.StatusBadRequest, `<div class="text-red-500">`+err.Error()+`</div>`)
		}
		return c.JSON(http.StatusBadRequest, map[string]string{"error": err.Error()})
	}
	if err := c.Validate(&req); err != nil {
		if c.Request().Header.Get("HX-Request") == "true" {
			return c.HTML(http.StatusBadRequest, `<div class="text-red-500">`+err.Error()+`</div>`)
		}
		return c.JSON(http.StatusBadRequest, map[string]string{"error": err.Error()})
	}

	// Check if user already exists
	if _, err := h.db.GetUserByEmail(c.Request().Context(), req.Email); err == nil {
		if c.Request().Header.Get("HX-Request") == "true" {
			return c.HTML(http.StatusConflict, `<div class="text-red-500">Email already exists</div>`)
		}
		return c.JSON(http.StatusConflict, map[string]string{"error": "email already exists"})
	}

	if _, err := h.db.GetUserByUsername(c.Request().Context(), req.Username); err == nil {
		if c.Request().Header.Get("HX-Request") == "true" {
			return c.HTML(http.StatusConflict, `<div class="text-red-500">Username already exists</div>`)
		}
		return c.JSON(http.StatusConflict, map[string]string{"error": "username already exists"})
	}

	// Hash password
	hashedPassword, err := bcrypt.GenerateFromPassword([]byte(req.Password), bcrypt.DefaultCost)
	if err != nil {
		if c.Request().Header.Get("HX-Request") == "true" {
			return c.HTML(http.StatusInternalServerError, `<div class="text-red-500">Failed to hash password</div>`)
		}
		return c.JSON(http.StatusInternalServerError, map[string]string{"error": "failed to hash password"})
	}

	// Create user
	user, err := h.db.CreateUser(c.Request().Context(), database.CreateUserParams{
		Email:        req.Email,
		Username:     req.Username,
		PasswordHash: string(hashedPassword),
	})
	if err != nil {
		if c.Request().Header.Get("HX-Request") == "true" {
			return c.HTML(http.StatusInternalServerError, `<div class="text-red-500">`+err.Error()+`</div>`)
		}
		return c.JSON(http.StatusInternalServerError, map[string]string{"error": err.Error()})
	}

	// Generate JWT
	token, err := h.generateJWT(uuid.UUID(user.ID.Bytes).String())
	if err != nil {
		if c.Request().Header.Get("HX-Request") == "true" {
			return c.HTML(http.StatusInternalServerError, `<div class="text-red-500">Failed to generate token</div>`)
		}
		return c.JSON(http.StatusInternalServerError, map[string]string{"error": "failed to generate token"})
	}

	// Check if request is from HTMX
	if c.Request().Header.Get("HX-Request") == "true" {
		// Return HTML with script to set token and redirect
		html := fmt.Sprintf(`<div class="text-green-500">Registration successful! Redirecting...</div>
<script>
localStorage.setItem('token', '%s');
localStorage.setItem('user', JSON.stringify(%s));
window.location.href = '/';
</script>`, token, fmt.Sprintf(`{"id":"%s","email":"%s","username":"%s"}`, uuid.UUID(user.ID.Bytes).String(), user.Email, user.Username))
		return c.HTML(http.StatusCreated, html)
	}

	return c.JSON(http.StatusCreated, AuthResponse{
		Token: token,
		User: UserProfile{
			ID:       uuid.UUID(user.ID.Bytes).String(),
			Email:    user.Email,
			Username: user.Username,
		},
	})
}

// Login handles POST /api/auth/login
func (h *AuthHandler) Login(c echo.Context) error {
	// Debug logging
	fmt.Printf("Login request - Content-Type: %s\n", c.Request().Header.Get("Content-Type"))
	fmt.Printf("Form values - login: %s, password: %s\n", c.FormValue("login"), c.FormValue("password"))

	// Try form data first (HTMX), then JSON (Bruno)
	login := c.FormValue("login")
	password := c.FormValue("password")

	if login == "" || password == "" {
		fmt.Printf("Form values empty, trying JSON bind\n")
		// Fallback to JSON binding
		req := LoginRequest{}
		if err := c.Bind(&req); err != nil {
			fmt.Printf("JSON bind error: %v\n", err)
			if c.Request().Header.Get("HX-Request") == "true" {
				return c.HTML(http.StatusBadRequest, `<div class="text-red-500">Invalid request</div>`)
			}
			return c.JSON(http.StatusBadRequest, map[string]string{"error": "invalid request"})
		}
		if err := c.Validate(&req); err != nil {
			fmt.Printf("Validation error: %v\n", err)
			if c.Request().Header.Get("HX-Request") == "true" {
				return c.HTML(http.StatusBadRequest, `<div class="text-red-500">`+err.Error()+`</div>`)
			}
			return c.JSON(http.StatusBadRequest, map[string]string{"error": err.Error()})
		}
		login = req.Login
		password = req.Password
		fmt.Printf("JSON bind success - login: %s\n", login)
	}

	req := LoginRequest{Login: login, Password: password}
	if err := c.Validate(&req); err != nil {
		fmt.Printf("Final validation error: %v\n", err)
		if c.Request().Header.Get("HX-Request") == "true" {
			return c.HTML(http.StatusBadRequest, `<div class="text-red-500">`+err.Error()+`</div>`)
		}
		return c.JSON(http.StatusBadRequest, map[string]string{"error": err.Error()})
	}
	if err := c.Validate(&req); err != nil {
		if c.Request().Header.Get("HX-Request") == "true" {
			return c.HTML(http.StatusBadRequest, `<div class="text-red-500">`+err.Error()+`</div>`)
		}
		return c.JSON(http.StatusBadRequest, map[string]string{"error": err.Error()})
	}

	// Get user by email or username
	user, err := h.db.GetUserByEmailOrUsername(c.Request().Context(), req.Login)
	if err != nil {
		if c.Request().Header.Get("HX-Request") == "true" {
			return c.HTML(http.StatusUnauthorized, `<div class="text-red-500">Invalid credentials</div>`)
		}
		return c.JSON(http.StatusUnauthorized, map[string]string{"error": "invalid credentials"})
	}

	// Check password
	if err := bcrypt.CompareHashAndPassword([]byte(user.PasswordHash), []byte(req.Password)); err != nil {
		if c.Request().Header.Get("HX-Request") == "true" {
			return c.HTML(http.StatusUnauthorized, `<div class="text-red-500">Invalid credentials</div>`)
		}
		return c.JSON(http.StatusUnauthorized, map[string]string{"error": "invalid credentials"})
	}

	// Generate JWT
	token, err := h.generateJWT(uuid.UUID(user.ID.Bytes).String())
	if err != nil {
		if c.Request().Header.Get("HX-Request") == "true" {
			return c.HTML(http.StatusInternalServerError, `<div class="text-red-500">Failed to generate token</div>`)
		}
		return c.JSON(http.StatusInternalServerError, map[string]string{"error": "failed to generate token"})
	}

	// Check if request is from HTMX
	if c.Request().Header.Get("HX-Request") == "true" {
		// Return HTML with script to set token and redirect
		html := fmt.Sprintf(`<div class="text-green-500">Login successful! Redirecting...</div>
<script>
localStorage.setItem('token', '%s');
localStorage.setItem('user', JSON.stringify(%s));
window.location.href = '/';
</script>`, token, fmt.Sprintf(`{"id":"%s","email":"%s","username":"%s"}`, uuid.UUID(user.ID.Bytes).String(), user.Email, user.Username))
		return c.HTML(http.StatusOK, html)
	}

	return c.JSON(http.StatusOK, AuthResponse{
		Token: token,
		User: UserProfile{
			ID:       uuid.UUID(user.ID.Bytes).String(),
			Email:    user.Email,
			Username: user.Username,
		},
	})
}

// GetProfile handles GET /api/auth/profile
func (h *AuthHandler) GetProfile(c echo.Context) error {
	userID := c.Get("user_id").(string)
	userUUID, err := uuid.Parse(userID)
	if err != nil {
		return c.JSON(http.StatusBadRequest, map[string]string{"error": "invalid user id"})
	}

	user, err := h.db.GetUser(c.Request().Context(), pgtype.UUID{Bytes: userUUID, Valid: true})
	if err != nil {
		return c.JSON(http.StatusNotFound, map[string]string{"error": "user not found"})
	}

	return c.JSON(http.StatusOK, UserProfile{
		ID:       uuid.UUID(user.ID.Bytes).String(),
		Email:    user.Email,
		Username: user.Username,
	})
}

// ListUsers handles GET /api/users
func (h *AuthHandler) ListUsers(c echo.Context) error {
	users, err := h.db.ListUsers(c.Request().Context())
	if err != nil {
		return c.JSON(http.StatusInternalServerError, map[string]string{"error": err.Error()})
	}

	type UserList struct {
		ID        string `json:"id"`
		Email     string `json:"email"`
		Username  string `json:"username"`
		Theme     string `json:"theme"`
		CreatedAt string `json:"created_at"`
		UpdatedAt string `json:"updated_at"`
	}

	var userList []UserList
	for _, u := range users {
		theme := ""
		if u.Theme.Valid {
			theme = u.Theme.String
		}
		createdAt := ""
		if u.CreatedAt.Valid {
			createdAt = u.CreatedAt.Time.Format("2006-01-02T15:04:05Z07:00")
		}
		updatedAt := ""
		if u.UpdatedAt.Valid {
			updatedAt = u.UpdatedAt.Time.Format("2006-01-02T15:04:05Z07:00")
		}
		userList = append(userList, UserList{
			ID:        uuid.UUID(u.ID.Bytes).String(),
			Email:     u.Email,
			Username:  u.Username,
			Theme:     theme,
			CreatedAt: createdAt,
			UpdatedAt: updatedAt,
		})
	}

	return c.JSON(http.StatusOK, userList)
}

type AddEbookFolderRequest struct {
	FolderPath string `json:"folder_path" validate:"required"`
}

type EbookFolderResponse struct {
	ID         string `json:"id"`
	UserID     string `json:"user_id"`
	FolderPath string `json:"folder_path"`
	CreatedAt  string `json:"created_at"`
}

// AddEbookFolder handles POST /api/auth/ebook-folders
func (h *AuthHandler) AddEbookFolder(c echo.Context) error {
	userID := c.Get("user_id").(string)
	userUUID, err := uuid.Parse(userID)
	if err != nil {
		return c.JSON(http.StatusBadRequest, map[string]string{"error": "invalid user id"})
	}

	var req AddEbookFolderRequest
	if err := c.Bind(&req); err != nil {
		return c.JSON(http.StatusBadRequest, map[string]string{"error": "invalid request"})
	}
	if err := c.Validate(&req); err != nil {
		return c.JSON(http.StatusBadRequest, map[string]string{"error": err.Error()})
	}

	folder, err := h.db.AddUserEbookFolder(c.Request().Context(), database.AddUserEbookFolderParams{
		UserID:     pgtype.UUID{Bytes: userUUID, Valid: true},
		FolderPath: req.FolderPath,
	})
	if err != nil {
		return c.JSON(http.StatusInternalServerError, map[string]string{"error": err.Error()})
	}

	return c.JSON(http.StatusCreated, EbookFolderResponse{
		ID:         uuid.UUID(folder.ID.Bytes).String(),
		UserID:     uuid.UUID(folder.UserID.Bytes).String(),
		FolderPath: folder.FolderPath,
		CreatedAt:  folder.CreatedAt.Time.Format("2006-01-02T15:04:05Z07:00"),
	})
}

// GetEbookFolders handles GET /api/auth/ebook-folders
func (h *AuthHandler) GetEbookFolders(c echo.Context) error {
	userID := c.Get("user_id").(string)
	userUUID, err := uuid.Parse(userID)
	if err != nil {
		return c.JSON(http.StatusBadRequest, map[string]string{"error": "invalid user id"})
	}

	folders, err := h.db.GetUserEbookFolders(c.Request().Context(), pgtype.UUID{Bytes: userUUID, Valid: true})
	if err != nil {
		return c.JSON(http.StatusInternalServerError, map[string]string{"error": err.Error()})
	}

	var response []EbookFolderResponse
	for _, folder := range folders {
		response = append(response, EbookFolderResponse{
			ID:         uuid.UUID(folder.ID.Bytes).String(),
			UserID:     uuid.UUID(folder.UserID.Bytes).String(),
			FolderPath: folder.FolderPath,
			CreatedAt:  folder.CreatedAt.Time.Format("2006-01-02T15:04:05Z07:00"),
		})
	}

	return c.JSON(http.StatusOK, response)
}

// DeleteEbookFolder handles DELETE /api/auth/ebook-folders/:folderPath
func (h *AuthHandler) DeleteEbookFolder(c echo.Context) error {
	userID := c.Get("user_id").(string)
	userUUID, err := uuid.Parse(userID)
	if err != nil {
		return c.JSON(http.StatusBadRequest, map[string]string{"error": "invalid user id"})
	}

	folderPath := c.Param("folderPath")
	if folderPath == "" {
		return c.JSON(http.StatusBadRequest, map[string]string{"error": "folder path is required"})
	}

	err = h.db.DeleteUserEbookFolder(c.Request().Context(), database.DeleteUserEbookFolderParams{
		UserID:     pgtype.UUID{Bytes: userUUID, Valid: true},
		FolderPath: folderPath,
	})
	if err != nil {
		return c.JSON(http.StatusInternalServerError, map[string]string{"error": err.Error()})
	}

	return c.JSON(http.StatusOK, map[string]string{"message": "ebook folder removed"})
}

type UpdateThemeRequest struct {
	Theme string `json:"theme" validate:"required"`
}

// UpdateTheme handles PUT /api/auth/theme
func (h *AuthHandler) UpdateTheme(c echo.Context) error {
	userID := c.Get("user_id").(string)
	userUUID, err := uuid.Parse(userID)
	if err != nil {
		return c.JSON(http.StatusBadRequest, map[string]string{"error": "invalid user id"})
	}

	var req UpdateThemeRequest
	if err := c.Bind(&req); err != nil {
		return c.JSON(http.StatusBadRequest, map[string]string{"error": "invalid request"})
	}
	if err := c.Validate(&req); err != nil {
		return c.JSON(http.StatusBadRequest, map[string]string{"error": err.Error()})
	}

	err = h.db.UpdateUserTheme(c.Request().Context(), database.UpdateUserThemeParams{
		ID:    pgtype.UUID{Bytes: userUUID, Valid: true},
		Theme: pgtype.Text{String: req.Theme, Valid: req.Theme != ""},
	})
	if err != nil {
		return c.JSON(http.StatusInternalServerError, map[string]string{"error": err.Error()})
	}

	return c.JSON(http.StatusOK, map[string]string{"message": "theme updated successfully"})
}

type UpdateUsernameRequest struct {
	Username string `json:"username" validate:"required,min=3,max=50"`
}

// UpdateUsername handles PUT /api/user/username
func (h *AuthHandler) UpdateUsername(c echo.Context) error {
	userID := c.Get("user_id").(string)
	userUUID, err := uuid.Parse(userID)
	if err != nil {
		return c.JSON(http.StatusBadRequest, map[string]string{"error": "invalid user id"})
	}

	var req UpdateUsernameRequest
	if err := c.Bind(&req); err != nil {
		return c.JSON(http.StatusBadRequest, map[string]string{"error": "invalid request"})
	}
	if err := c.Validate(&req); err != nil {
		return c.JSON(http.StatusBadRequest, map[string]string{"error": err.Error()})
	}

	// Check if username is already taken by another user
	existingUser, err := h.db.GetUserByUsername(c.Request().Context(), req.Username)
	if err == nil && uuid.UUID(existingUser.ID.Bytes) != userUUID {
		return c.JSON(http.StatusConflict, map[string]string{"error": "username already taken"})
	}

	// Update username
	err = h.db.UpdateUsername(c.Request().Context(), database.UpdateUsernameParams{
		ID:       pgtype.UUID{Bytes: userUUID, Valid: true},
		Username: req.Username,
	})
	if err != nil {
		return c.JSON(http.StatusInternalServerError, map[string]string{"error": err.Error()})
	}

	return c.JSON(http.StatusOK, map[string]string{"message": "username updated successfully"})
}

type UpdateEmailRequest struct {
	Email string `json:"email" validate:"required,email"`
}

// UpdateEmail handles PUT /api/user/email
func (h *AuthHandler) UpdateEmail(c echo.Context) error {
	userID := c.Get("user_id").(string)
	userUUID, err := uuid.Parse(userID)
	if err != nil {
		return c.JSON(http.StatusBadRequest, map[string]string{"error": "invalid user id"})
	}

	var req UpdateEmailRequest
	if err := c.Bind(&req); err != nil {
		return c.JSON(http.StatusBadRequest, map[string]string{"error": "invalid request"})
	}
	if err := c.Validate(&req); err != nil {
		return c.JSON(http.StatusBadRequest, map[string]string{"error": err.Error()})
	}

	// Check if email is already taken by another user
	existingUser, err := h.db.GetUserByEmail(c.Request().Context(), req.Email)
	if err == nil && uuid.UUID(existingUser.ID.Bytes) != userUUID {
		return c.JSON(http.StatusConflict, map[string]string{"error": "email already taken"})
	}

	// Update email
	err = h.db.UpdateEmail(c.Request().Context(), database.UpdateEmailParams{
		ID:    pgtype.UUID{Bytes: userUUID, Valid: true},
		Email: req.Email,
	})
	if err != nil {
		return c.JSON(http.StatusInternalServerError, map[string]string{"error": err.Error()})
	}

	return c.JSON(http.StatusOK, map[string]string{"message": "email updated successfully"})
}

type UpdatePasswordRequest struct {
	CurrentPassword string `json:"current_password" validate:"required"`
	NewPassword     string `json:"new_password" validate:"required,min=6"`
	ConfirmPassword string `json:"confirm_password" validate:"required"`
}

// UpdatePassword handles PUT /api/user/password
func (h *AuthHandler) UpdatePassword(c echo.Context) error {
	userID := c.Get("user_id").(string)
	userUUID, err := uuid.Parse(userID)
	if err != nil {
		return c.JSON(http.StatusBadRequest, map[string]string{"error": "invalid user id"})
	}

	var req UpdatePasswordRequest
	if err := c.Bind(&req); err != nil {
		return c.JSON(http.StatusBadRequest, map[string]string{"error": "invalid request"})
	}
	if err := c.Validate(&req); err != nil {
		return c.JSON(http.StatusBadRequest, map[string]string{"error": err.Error()})
	}

	// Check if new passwords match
	if req.NewPassword != req.ConfirmPassword {
		return c.JSON(http.StatusBadRequest, map[string]string{"error": "new passwords do not match"})
	}

	// Get current user's password hash
	passwordHash, err := h.db.GetUserPasswordHash(c.Request().Context(), pgtype.UUID{Bytes: userUUID, Valid: true})
	if err != nil {
		return c.JSON(http.StatusInternalServerError, map[string]string{"error": "failed to get user"})
	}

	// Verify current password
	if err := bcrypt.CompareHashAndPassword([]byte(passwordHash), []byte(req.CurrentPassword)); err != nil {
		return c.JSON(http.StatusUnauthorized, map[string]string{"error": "current password is incorrect"})
	}

	// Hash new password
	hashedPassword, err := bcrypt.GenerateFromPassword([]byte(req.NewPassword), bcrypt.DefaultCost)
	if err != nil {
		return c.JSON(http.StatusInternalServerError, map[string]string{"error": "failed to hash password"})
	}

	// Update password
	err = h.db.UpdatePassword(c.Request().Context(), database.UpdatePasswordParams{
		ID:           pgtype.UUID{Bytes: userUUID, Valid: true},
		PasswordHash: string(hashedPassword),
	})
	if err != nil {
		return c.JSON(http.StatusInternalServerError, map[string]string{"error": err.Error()})
	}

	return c.JSON(http.StatusOK, map[string]string{"message": "password updated successfully"})
}

// DeleteAccount handles DELETE /api/user/account
func (h *AuthHandler) DeleteAccount(c echo.Context) error {
	userID := c.Get("user_id").(string)
	userUUID, err := uuid.Parse(userID)
	if err != nil {
		return c.JSON(http.StatusBadRequest, map[string]string{"error": "invalid user id"})
	}

	// Delete user (this will cascade to delete all related data)
	err = h.db.DeleteUser(c.Request().Context(), pgtype.UUID{Bytes: userUUID, Valid: true})
	if err != nil {
		return c.JSON(http.StatusInternalServerError, map[string]string{"error": err.Error()})
	}

	return c.JSON(http.StatusOK, map[string]string{"message": "account deleted successfully"})
}

func (h *AuthHandler) generateJWT(userID string) (string, error) {
	claims := jwtgo.MapClaims{
		"user_id": userID,
		"exp":     time.Now().Add(24 * time.Hour).Unix(),
		"iat":     time.Now().Unix(),
	}

	token := jwtgo.NewWithClaims(jwtgo.SigningMethodHS256, claims)
	return token.SignedString(h.jwtKey)
}