const games = require('./games')
const VM = require('./vm')
const session = async (message, state) => {
  const ret = await (async () => {
    if (message.content.startsWith('?') || message.content.startsWith('!')) {
      message.reply('_For a list of bot commands, type \`/help\`._')
    }
    if (message.content.startsWith('/')) {
      const args = message.content.split(' ').filter(x => x)
      const cmd = args.shift().toLowerCase().substr(1)
      if (commands[cmd]) {
        return await commands[cmd](message, state, ...args)
      } else {
        doNotUnderstand(message)
      }
    } else if (!state.doneIntro) {
      intro(message)
      return { doneIntro: true }
    } else if (!state.doneIntro2) {
      listGames(message, state)
      return { doneIntro2: true }
    } else if (!state.game) {
      return await chooseGame(message)
    } else {
      return await play(message, state)
    }
  })()
  console.log(`${message.author.username}: ${message.content}`)
  return Object.assign({}, ret, {
    content: message.content,
    username: message.author.username
  })
}

const intro = message => message.reply(`Hello, ${message.author}. Would you like to play a game?`)

const listGames = (message, state, text) => {
  message.reply(
    (text ? text + '\n' : '') +
    (state.game
      ? `You are currently playing ${games[state.game].name}.\n`
      : `You may choose one of the following adventures:\n`) + 
    games.map((game, i) => `${i + 1}. ${game.name}`).join('\n')
  )
}

const chooseGame = async message => {
  let game = games[parseInt(message.content) - 1] ||
      games[message.content.trim().toLowerCase()]

  if (game) {
    const gameState = await VM.play(game.data)
    message.reply(`_Loading ${game.name}..._\n\n${game.format(gameState.output)}`)
    return {
      game: game.name,
      gameState
    }
  } else  {
    doNotUnderstand(message)
    return {}
  }
}

const doNotUnderstand = message => message.reply(`I do not understand '${message.content}'. Do you need \`/help\`?`)

const play = async (message, state) => {
  const game = games[state.game]
  try {
    const gameState = await VM.play(game.data, state.gameState.save, message.content)
    message.reply(game.format(gameState.output))
    return {
      input: message.content,
      gameState
    }
  } catch (ex) {
    console.error(ex)
  }
}


const help = async (message, state) => {
  message.reply(
`Available commands:
  /help - Shows this message.
  /reset - Restarts the game you have selected.
  /exit - Closes the game you have selected.
  /games - List games
`) 
}

const reset = async (message, state) => {
  if (state.game) {
    return chooseGame(Object.assign(Object.create(message), {content: state.game}))
  } else {
    listGames(message, state, 'You do not have a game loaded.')
  }
}

const exit = async (message, state) => {
  if (state.game) {
    message.reply(`Shutting down ${state.game}`)
    return { game: null, gameState: null }
  } else {
    listGames(message, 'You do not have a game loaded.')
  }
}

commands = {
  help, reset, exit, games: listGames
}

module.exports = session