/*
ScheduleTogether Backend
Copyright (C) 2024, Zervó Zadachin

DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

This program is free software: you can redistribute it and/or modify
it under the terms of the GNU Affero General Public License version 3
as published by the Free Software Foundation.

This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU Affero General Public License version 3 for more details.

This program incorporates external libraries for certain functionalities.
These libraries are covered by their respective licenses, and their usage
agreements are as outlined in their respective documentation or source
code.

You should have received a copy of the GNU Affero General Public License
along with this program.  If not, see <http://www.gnu.org/licenses/>.
*/

package accounts

import (
	"errors"
	"regexp"

	"github.com/google/uuid"
	"github.com/kataras/iris/v12"
	"github.com/kataras/iris/v12/middleware/jwt"
	"gorm.io/gorm"

	db "git.zervo.org/scheduletogether/backend/internal/database"
	"git.zervo.org/scheduletogether/backend/pkg/helpers/logging"
	"git.zervo.org/scheduletogether/backend/pkg/helpers/validation"
	"git.zervo.org/scheduletogether/backend/pkg/types"
)

var logboi = logging.NewLogger("api.services.accounts")

// Reusable user account register/update request validation function
func validateUserProperties(ctx iris.Context, request types.AccountRegisterRequest) error {
	// Validate email
	if err := validation.ValidateEmail(request.Email); err != nil {
		ctx.StatusCode(iris.StatusBadRequest)
		ctx.JSON(types.UserRegisterFieldValidationErrorResponse{
			ValidationFailed: true,
			Email:            "Provided email address is not valid",
		})
		return errors.New("validation failed")
	}

	// Check if email already exists in database
	var existingEmailUser db.User
	err := db.Db.Where("email = ?", request.Email).First(&existingEmailUser).Error
	if err != gorm.ErrRecordNotFound {
		ctx.StatusCode(iris.StatusBadRequest)
		ctx.JSON(types.UserRegisterFieldValidationErrorResponse{
			ValidationFailed: true,
			Email:            "This email address is already in use by another account",
		})
		return errors.New("validation failed")
	}

	// Validate firstName
	if len(request.FirstName) > 50 {
		ctx.StatusCode(iris.StatusBadRequest)
		ctx.JSON(types.UserRegisterFieldValidationErrorResponse{
			ValidationFailed: true,
			FirstName:        "First name is too long",
		})
		return errors.New("validation failed")
	}

	// Validate lastName
	if len(request.LastName) > 50 {
		ctx.StatusCode(iris.StatusBadRequest)
		ctx.JSON(types.UserRegisterFieldValidationErrorResponse{
			ValidationFailed: true,
			LastName:         "Last name is too long",
		})
		return errors.New("validation failed")
	}

	// Validate username
	if len(request.Username) < 5 {
		ctx.StatusCode(iris.StatusBadRequest)
		ctx.JSON(types.UserRegisterFieldValidationErrorResponse{
			ValidationFailed: true,
			Username:         "Username is too short",
		})
		return errors.New("validation failed")
	}

	if len(request.Username) > 18 {
		ctx.StatusCode(iris.StatusBadRequest)
		ctx.JSON(types.UserRegisterFieldValidationErrorResponse{
			ValidationFailed: true,
			Username:         "Username is too long",
		})
		return errors.New("validation failed")
	}

	// Check if username already exists in database
	var existingUsernameUser db.User
	err = db.Db.Where("username = ?", request.Username).First(&existingUsernameUser).Error
	if err != gorm.ErrRecordNotFound {
		ctx.StatusCode(iris.StatusBadRequest)
		ctx.JSON(types.UserRegisterFieldValidationErrorResponse{
			ValidationFailed: true,
			Username:         "This username is already in use by another account",
		})
		return errors.New("validation failed")
	}

	// Validate password
	if len(request.Password) < 8 {
		ctx.StatusCode(iris.StatusBadRequest)
		ctx.JSON(types.UserRegisterFieldValidationErrorResponse{
			ValidationFailed: true,
			Password:         "Password is too short (minimum 8 characters)",
		})
		return errors.New("validation failed")
	}

	if len(request.Password) > 128 {
		ctx.StatusCode(iris.StatusBadRequest)
		ctx.JSON(types.UserRegisterFieldValidationErrorResponse{
			ValidationFailed: true,
			Password:         "Password is too long (maximum 128 characters)",
		})
		return errors.New("validation failed")
	}

	// Check that password contains a lowercase letter
	if !regexp.MustCompile(`[a-z]`).MatchString(request.Password) {
		ctx.StatusCode(iris.StatusBadRequest)
		ctx.JSON(types.UserRegisterFieldValidationErrorResponse{
			ValidationFailed: true,
			Password:         "Password must contain a lowercase letter",
		})
		return errors.New("validation failed")
	}

	// Check that password contains an uppercase letter
	if !regexp.MustCompile(`[A-Z]`).MatchString(request.Password) {
		ctx.StatusCode(iris.StatusBadRequest)
		ctx.JSON(types.UserRegisterFieldValidationErrorResponse{
			ValidationFailed: true,
			Password:         "Password must contain an uppercase letter",
		})
		return errors.New("validation failed")
	}

	// Check that password contains a number
	if !regexp.MustCompile(`[0-9]`).MatchString(request.Password) {
		ctx.StatusCode(iris.StatusBadRequest)
		ctx.JSON(types.UserRegisterFieldValidationErrorResponse{
			ValidationFailed: true,
			Password:         "Password must contain a number",
		})
		return errors.New("validation failed")
	}

	return nil
}

// generateUUID generates a new unused uuid
func generateUUID() (string, error) {
	for {
		// generate a new uuid
		uuid, err := uuid.NewRandom()
		if err != nil {
			return "", err
		}

		// check if the uuid already exists in the users table
		var user db.User
		err = db.Db.Where("uuid = ?", uuid.String()).First(&user).Error
		if err != nil && err != gorm.ErrRecordNotFound {
			return "", err
		}

		// if the uuid does not already exist in the users table, return it
		if err == gorm.ErrRecordNotFound {
			return uuid.String(), nil
		}
	}
}

// GetClaims returns the current authorized client claims
func GetClaims(ctx iris.Context) *types.Claims {
	claims := jwt.Get(ctx).(*types.Claims)
	return claims
}

// GetUserID returns the current authorized client's user id extracted from claims
func GetUserID(ctx iris.Context) uint {
	return GetClaims(ctx).UserId
}