package util

import (
	"strings"
	"unicode"
)

// Allowed special characters
const specialChars = "!@#$%^*-_=+~()[]{}"

var allowedSpecialChars map[rune]bool

func init() {
	allowedSpecialChars = make(map[rune]bool)
	for _, r := range []rune(specialChars) {
		allowedSpecialChars[r] = true
	}
}

func ValidateTypeName(input string) (string, bool) {
	// Trim leading and trailing spaces
	trimmed := strings.TrimSpace(input)

	// If the string is empty after trimming, return false
	if len(trimmed) == 0 {
		return "", false
	}

	runes := []rune(trimmed)

	if len(runes) > 30 {
		return "", false
	}

	// Dash cannot be at the beginning or end
	if allowedSpecialChars[runes[0]] || allowedSpecialChars[runes[len(runes)-1]] {
		return "", false
	}
	// if runes[0] == '-' || runes[len(runes)-1] == '-' {
	// 	return "", false
	// }

	var specialCount uint8
	for _, r := range runes {
		// Check if the character is a whitespace, which is not allowed
		if unicode.IsSpace(r) {
			return "", false
		}

		// Letters (including any alphabet) and digits are allowed
		if unicode.IsLetter(r) || unicode.IsDigit(r) {
			specialCount = 0
			continue
		}

		// Combining marks (accents) are allowed
		if unicode.IsMark(r) {
			specialCount = 0
			continue
		}

		// Check for allowed special characters
		if allowedSpecialChars[r] {
			if specialCount == 2 {
				return "", false
			}
			specialCount++
			continue
		}

		// If any other character is encountered, return false
		return "", false
	}

	// Return the trimmed string and true if all conditions are met
	return trimmed, true
}