package net.mezimmah.wkt9.keypad

import net.mezimmah.wkt9.exception.MissingLetterCode
import java.lang.StringBuilder

class Keypad {
    private val letterCodeMap: MutableMap<Char, Int> = mutableMapOf()

    init {
        KeyLayout.numeric.forEach { (key, code) ->
            indexKeyLetters(key, code)
        }
    }

    private fun indexKeyLetters(key: Key, code: Int) {
        KeyLayout.chars[key]?.map { letter ->
            letterCodeMap[letter] = code
        }
    }

    fun getCodeForWord(word: String): String {
        val builder = StringBuilder()
        val normalized = word.lowercase()

        for (letter in normalized) {
            val code = codeForLetter(letter) ?: throw MissingLetterCode("No code found for '$letter'")

            builder.append(code)
        }

        return builder.toString()
    }

    private fun codeForLetter(letter: Char): Int? {
        return letterCodeMap[letter]
    }
}