// Copyright (c) 2025 Nikolai Papin
//
// This file is part of Easywish
//
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// 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 General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with this program.  If not, see <https://www.gnu.org/licenses/>.

package validation

import (
	"easywish/config"
	"fmt"
	"regexp"
	"time"

	"github.com/go-playground/validator/v10"
)

type CustomValidatorHandler struct {
	Function func(fl validator.FieldLevel) bool
	FieldName string
}

func GetCustomHandlers() []CustomValidatorHandler {

	handlers := []CustomValidatorHandler{

		{
			FieldName: "username",
			Function: func(fl validator.FieldLevel) bool {
				username := fl.Field().String()
        return regexp.MustCompile(`^[a-zA-Z0-9_]{3,20}$`).MatchString(username)
		}},

		{
			FieldName: "guid",
			Function: func(fl validator.FieldLevel) bool {
				guid := fl.Field().String()
        return regexp.MustCompile(`^([{(]?([0-9a-fA-F]{8}-[0-9a-fA-F]{4}-[1-5][0-9a-fA-F]{3}-[89abAB][0-9a-fA-F]{3}-[0-9a-fA-F]{12})[})]?)$`).MatchString(guid)
		}},

		{
			FieldName: "name",
			Function: func(fl validator.FieldLevel) bool {
				username := fl.Field().String()
        return regexp.MustCompile(`^.{1,75}$`).MatchString(username)
		}},

		{
			FieldName: "bio",
			Function: func(fl validator.FieldLevel) bool {
				username := fl.Field().String()
        return regexp.MustCompile(`^.{1,512}$`).MatchString(username)
		}},

		{
			FieldName: "birthday_unix_milli",
			Function: func(fl validator.FieldLevel) bool {
			
			timestamp := fl.Field().Int()
			date := time.UnixMilli(timestamp)
			currentDate := time.Now()

			age := currentDate.Year() - date.Year()
			if currentDate.YearDay() < date.YearDay() {
				age--
			}

			return age >= 0 && age <= 122
		}},

		{
			FieldName: "color_hex",
			Function: func(fl validator.FieldLevel) bool {
				username := fl.Field().String()
        return regexp.MustCompile(`^#[0-9a-f]{6,6}$`).MatchString(username)
		}},

		{
			FieldName: "password",
			Function: func(fl validator.FieldLevel) bool {
				password := fl.Field().String()
				cfg := config.GetConfig()

				if cfg.PasswordMaxLength < len(password) || len(password) < cfg.PasswordMinLength {
					return false
				}

				if cfg.PasswordCheckNumbers && !regexp.MustCompile(`\d+`).MatchString(password) {
					return false
				}

				if cfg.PasswordCheckCases && !regexp.MustCompile(`^(?=.*[a-z])(?=.*[A-Z]).*$`).MatchString(password) ||
					cfg.PasswordCheckCharacters && !regexp.MustCompile(`[a-zA-Z]`).MatchString(password) {
						return false
				}

				if cfg.PasswordCheckSymbols && !regexp.MustCompile(`[.,/;'[\]\-=_+{}:"<>?\/|!@#$%^&*()~]`).MatchString(password) {
						return false
				}

				if cfg.PasswordCheckLeaked {
					// TODO: implement rockme check
				}

				return true
		}},

		{
			FieldName: "verification_code",
			Function: func(fl validator.FieldLevel) bool {
				codeType := fl.Param()
				code := fl.Field().String()
				
				if codeType == "reg" {
					return regexp.MustCompile(`[\d]{6,6}`).MatchString(code)
				}

				if codeType == "reset" {
					return regexp.MustCompile(
						`^[{(]?([0-9a-fA-F]{8}-[0-9a-fA-F]{4}-[1-5][0-9a-fA-F]{3}-[89abAB][0-9a-fA-F]{3}-[0-9a-fA-F]{12})[})]?$`,
					).MatchString(code)
				}

				panic(fmt.Sprintf("'%s' is not a valid verification code type", codeType))
		}},

		{
			FieldName: "upload_id",
			Function: func(fl validator.FieldLevel) bool {
				uploadType := fl.Param()
				uploadID := fl.Field().String()

				pattern := fmt.Sprintf(
					"^%s-([{(]?([0-9a-fA-F]{8}-[0-9a-fA-F]{4}-[1-5][0-9a-fA-F]{3}-[89abAB][0-9a-fA-F]{3}-[0-9a-fA-F]{12})[})]?)$", 
					uploadType,
				)

				return regexp.MustCompile(pattern).MatchString(uploadID)
		}},
		
	} 

	return handlers
}