package pkg

import (
	"fmt"
	"strconv"
	"strings"
)

// 生成一个包含楼层的人脸id,解析楼层
// 使用48位源id, 其中前41位是imageid, 不可以修改 41-43位填 06 代表图像, +99 + 3位楼层(第一位0表示正,1表示负)
func GenerateFaceIdContainFloor(srcId, floorStr string) string {
	floorNum, _ := parseFloor(floorStr)
	newId := srcId[0:43] + "99" + floorNum
	//newId := srcId[0:43] + "99" + floorNum + snowflake.CreateRandomNumber(1)

	return newId
}

func ParseFloorFromId(srcId string) (string, error) {
	if len(srcId) != 48 {
		return "", fmt.Errorf("invalid id %s", srcId)
	}

	if srcId[43:45] != "99" {
		return "", fmt.Errorf("invalid flag %s", srcId[43:45])
	}

	return restoreFloor(srcId[45:48])
}

// parseFloor parses the floor string and returns a three-character string
func parseFloor(floor string) (string, error) {
	var sign string
	var number string

	// Check if the floor is negative
	if strings.HasPrefix(floor, "-") {
		sign = "1"
		number = floor[1 : len(floor)-1]
	} else {
		sign = "0"
		number = floor[:len(floor)-1]
	}

	// Convert the number to an integer to validate and ensure it is a valid number
	if _, err := strconv.Atoi(number); err != nil {
		return "", err
	}

	// Format the number to be two digits
	formattedNumber := fmt.Sprintf("%02s", number)

	return sign + formattedNumber, nil
}

// restoreFloor restores the three-character string back to the original floor string
func restoreFloor(encoded string) (string, error) {
	if len(encoded) != 3 {
		return "", fmt.Errorf("encoded string must be 3 characters long")
	}

	sign := encoded[0]
	number := encoded[1:]

	// Convert the number back to integer to remove any leading zeros
	parsedNumber, err := strconv.Atoi(number)
	if err != nil {
		return "", err
	}

	var restoredFloor string
	if sign == '1' {
		restoredFloor = fmt.Sprintf("-%dF", parsedNumber)
	} else if sign == '0' {
		restoredFloor = fmt.Sprintf("%dF", parsedNumber)
	} else {
		return "", fmt.Errorf("invalid sign character in encoded string")
	}

	return restoredFloor, nil
}