package terminal

import com.googlecode.lanterna.TerminalPosition
import com.googlecode.lanterna.TerminalSize
import com.googlecode.lanterna.input.KeyStroke
import com.googlecode.lanterna.input.KeyType
import com.googlecode.lanterna.terminal.virtual.DefaultVirtualTerminal
import com.googlecode.lanterna.terminal.virtual.VirtualTerminal
import org.assertj.core.api.Assertions.assertThat
import org.junit.Assert.fail
import terminal.LispTerminal.END_OF_SEGMENT
import java.io.IOException
import java.io.PipedInputStream
import java.io.PipedOutputStream

class VirtualTerminalInteractor {

    private val inputWriter = PipedOutputStream()
    private val inputReader = PipedInputStream()
    private val outputWriter = PipedOutputStream()
    private val outputReader = PipedInputStream()
    private val flushListener = FlushListener()

    private val virtualTerminal: VirtualTerminal = DefaultVirtualTerminal().apply {
        addVirtualTerminalListener(flushListener)
    }

    val configuration = TerminalConfiguration().also {
        it.setInputPair(inputWriter, inputReader)
        it.setOutputPair(outputWriter, outputReader)
        it.terminal = virtualTerminal
    }

    private val lispTerminal = LispTerminal(configuration)

    fun start() {
        lispTerminal.start()
    }

    fun stop() {
        lispTerminal.stop()
        outputWriter.close()
    }

    fun pressKey(keyType: KeyType) {
        virtualTerminal.addInput(KeyStroke(keyType))
        waitForFlushes(1)
    }

    fun pressKeyTimes(keyType: KeyType, times: Int) {
        for (i in times downTo 1)
            virtualTerminal.addInput(KeyStroke(keyType))

        waitForFlushes(times)
    }

    fun pressControlKey(keyType: KeyType) {
        virtualTerminal.addInput(KeyStroke(keyType, true, false))
        waitForFlushes(1)
    }

    fun enterCharacter(character: Char) {
        virtualTerminal.addInput(KeyStroke(character, false, false))
        waitForFlushes(1)
    }

    fun enterControlCharacter(character: Char) {
        virtualTerminal.addInput(KeyStroke(character, true, false))
        waitForFlushes(1)
    }

    fun enterCharacters(characters: String) {
        for (c in characters.toCharArray())
            virtualTerminal.addInput(KeyStroke(c, false, false))

        waitForFlushes(characters.length)
    }

    fun produceOutput(output: String) {
        for (c in output.toCharArray())
            outputWriter.write(c.toInt())

        outputWriter.write(END_OF_SEGMENT.toInt())
        outputWriter.flush()
        waitForFlushes(1)
    }

    private fun waitForFlushes(flushCount: Int) {
        synchronized(flushListener.lock) {
            while (flushListener.flushCount < flushCount)
                flushListener.lock.wait()

            flushListener.reduceFlushCount(flushCount)
        }
    }

    fun waitForPrompt() {
        waitForFlushes(1)
    }

    fun setColumns(columns: Int) {
        val rows = virtualTerminal.terminalSize.rows
        virtualTerminal.terminalSize = TerminalSize(columns, rows)
    }

    fun setRows(rows: Int) {
        val columns = virtualTerminal.terminalSize.columns
        virtualTerminal.terminalSize = TerminalSize(columns, rows)
    }

    fun assertCursorPosition(column: Int, row: Int) {
        assertThat(virtualTerminal.cursorPosition.column).isEqualTo(column)
        assertThat(virtualTerminal.cursorPosition.row).isEqualTo(row)
    }

    fun assertScreenText(vararg rows: String) {
        for (row in rows.indices)
            for (column in 0 until rows[row].length)
                assertCharacterAtPosition(rows[row][column], column, row)
    }

    private fun assertCharacterAtPosition(character: Char, column: Int, row: Int) {
        val position = TerminalPosition(column, row)
        val expected = character.toString()
        val actual = virtualTerminal.getCharacter(position).character.toString()
        assertThat(actual).isEqualTo(expected)
    }

    fun assertInputWritten(expected: String) {
        var actual = ""

        inputWriter.close()

        var c = inputReader.read()
        while (c != -1) {
            actual += c.toChar()
            c = inputReader.read()
        }

        assertThat(actual).isEqualTo(expected)
    }

    fun assertInputStreamClosed() {
        try {
            inputWriter.write(0)
            fail("input stream not closed")
        } catch (ignored: IOException) {
        }
    }
}