package net.mezimmah.wkt9.keypad

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

class Keypad(
    private val keyCodeMapping: KeyCodeMapping,
    private val letterLayout: Map<Key, List<Char>>
) {
    private lateinit var letterKeyMap: Map<Char, Key>
    private lateinit var keyIsLetterMap: Map<Key, Boolean>
    private var emojiCodes = mapOf(
        "❤️" to "143278",
        "\uD83D\uDE18" to "15477"
    )

    init {
        initKeyMaps(letterLayout)
    }

    fun getKey(keyCode: Int): Key? {
        return keyCodeMapping.key(keyCode)
    }

    fun getCharacter(key: Key, idx: Int): Char {
        val chars = letterLayout[key]!!
        val length = chars.size
        val wrappedIdx = idx % (length - 1) + 1
        return chars[wrappedIdx]
    }

    fun getDigit(key: Key): Char? {
        val letters = letterLayout[key] ?: return null
        return if (letters.isNotEmpty() && letters[0].isDigit()) letters[0] else null
    }

    fun getCodeForWord(word: String): String {
        if (emojiCodes.keys.contains(word)) return emojiCodes[word]!!

        val builder = StringBuilder()

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

            builder.append(code)
        }

        return builder.toString()
    }

    private fun codeForLetter(letter: Char): Char? {
        return letterKeyMap[letter]?.code
    }

    private fun initKeyMaps(layout: Map<Key, List<Char>>): Map<Char, Key> {
        val letterKeyMap = HashMap<Char, Key>()
        val keyIsLetterMap = HashMap<Key, Boolean>()

        this.letterKeyMap = letterKeyMap
        this.keyIsLetterMap = keyIsLetterMap

        for ((key, characters) in layout) {
            for (char in characters) {
                letterKeyMap[char] = key

                if (!KeyLayout.nonAlphaNumeric.contains(char)) {
                    letterKeyMap[char.uppercaseChar()] = key
                    keyIsLetterMap[key] = true
                } else if (keyIsLetterMap[key] == null) keyIsLetterMap[key] = false
            }
        }

        return letterKeyMap
    }
}