package com.santalu.maskara

/**
 * Created by fatih.santalu on 7/7/2020.
 */

data class Mask(
    val value: String,
    val character: Char = value.mostOccurred(),
    val style: MaskStyle = MaskStyle.NORMAL
) {

    init {
        require(value.isNotEmpty()) { ERROR_EMPTY_VALUE }
        require(value.contains(character)) { ERROR_INVALID_CHARACTER }
    }

    companion object {
        const val ERROR_EMPTY_VALUE = "Mask cannot be empty"
        const val ERROR_INVALID_CHARACTER = "Mask does not contain specified character"
    }
}

/**
 * Returns the character with most occurrences
 */
internal fun String.mostOccurred(): Char {
    require(isNotEmpty()) { Mask.ERROR_EMPTY_VALUE }
    val result = groupBy { it }.maxBy { it.value.size }
    return result?.key ?: first()
}