SpeakerType = {
  NONE = 0,
  MAN = 1,
  WOMAN = 2,
  BOY = 3,
  GIRL = 4,
  NONHUMAN = 5
}

Direction = {
  UP = 0,
  UP_RIGHT = 1,
  RIGHT = 2,
  DOWN_RIGHT = 3,
  DOWN = 4,
  DOWN_LEFT = 5,
  LEFT = 6,
  UP_LEFT = 7
}

CharacterState = {
  STILL = 0,
  WALKING = 1,
  CROUCHING = 2,
  RUNNING = 3
}

SpriteLayer = {
  NORMAL = 0,
  ABOVE = 1
}

gamestate = {}

--- Yields until the specified amount of time has passed.
-- @param time in milliseconds
function Delay(time)
  while time > 0 do
    time = time - coroutine.yield()
  end
end

--- Starts a cutscene.
-- This takes care of showing the cutscene bars, as well as halting character
-- movement. It does not block.
function StartCutscene()
  local playerId = getPlayerSprite()
  local playerSprite = getSprite(playerId)
  playerSprite.controllable = false
  character():halt(playerId)
  message():displayCutsceneBars()
end

--- Queues a message for display.
-- Non-blocking! If you want to block until the message has been fully
-- revealed, use WaitForEndOfMessage().
-- @param msg the text of the message
-- @param name the name of the character speaking (leave blank to not show a character name)
-- @param type the SpeakerType for the character, which determines which beep sound is played, if any
function DisplayMessage(msg, name, type)
  message():displayMessage(msg, name, type)
end

--- Queues a choice prompt for the player.
-- This should be called after DisplayMessage(), as it is not valid for a choice
-- prompt to be the first line of the text box. This also does not block. You
-- should use WaitForEndOfMessage() after this.
-- @param one the text of the first option
-- @param two the text of the second option
function ShowChoice(one, two)
  message():showChoice(one, two)
end

--- Gets the result of the last choice prompt.
-- @return 0 for the left choice, 1 for the right choice
function GetChoiceSelection()
  return message():getChoiceSelection()
end

--- Yields until all queued messages / choice prompts have been dismissed.
-- This does not hide the cutscene bars, nor does it wait for them to hide.
function WaitForEndOfMessage()
  while (message().isMessageActive) do
    coroutine.yield()
  end
end

--- Hides the cutscene bars.
-- This also re-enables player movement.
function HideCutsceneBars()
  WaitForEndOfMessage()
  message():hideCutsceneBars()

  local playerId = getPlayerSprite()
  local playerSprite = getSprite(playerId)
  playerSprite.controllable = true
end

function GetPosition(spriteName)
  local spriteId = getSpriteByAlias(spriteName)
  local sprite = getSprite(spriteId)
  return sprite.loc
end

function SetDirection(spriteName, dir)
  local spriteId = getSpriteByAlias(spriteName)
  animation():setSpriteDirection(spriteId, dir)
end

function SetAnimation(spriteName, animName)
  local spriteId = getSpriteByAlias(spriteName)
  animation():setSpriteAnimation(spriteId, animName)
end

function WaitForAnimation(spriteName)
  local spriteId = getSpriteByAlias(spriteName)
  local sprite = getSprite(spriteId)
  repeat
    coroutine.yield()
  until sprite.animFinished
end

function PlaySound(filename)
  mixer():playSound("../res/sfx/" .. filename)
end

function LoopSound(filename)
  return mixer():loopSound("../res/sfx/" .. filename)
end

function StopSound(soundId)
  mixer():stopChannel(soundId)
end

function FadeToBlack(length)
  effect():fadeScreen(length, 1.0)
  repeat
    coroutine.yield()
  until effect():isScreenFadeComplete()
end

function RemoveFadeout(length)
  effect():fadeScreen(length, 0.0)
  repeat
    coroutine.yield()
  until effect():isScreenFadeComplete()
end

function FadeMap(length, amount)
  effect():fadeMap(length, amount)
end

function WaitForMapFade()
  while not effect():isMapFadeComplete() do
    coroutine.yield()
  end
end

function ShakeCamera(period)
  effect():shakeCamera(period)
end

function StopShakingCamera()
  effect():stopShakingCamera()
end

function PanToSprite(spriteName, length)
  local spriteId = getSpriteByAlias(spriteName)
  camera():panToSprite(spriteId, length)
end

function WaitForPan()
  while camera():isPanning() do
    coroutine.yield()
  end
end

function ReturnCamera(length)
  local playerId = getPlayerSprite()
  camera():panToSprite(playerId, length)

  while camera():isPanning() do
    coroutine.yield()
  end

  camera():setFollowingSprite(playerId)
  camera():unlockCamera()
end

function SetPartyDirection(spriteId, direction)
  animation():setSpriteDirection(spriteId, direction)

  local sprite = getSprite(spriteId)

  for i=1,#sprite.followers do
    animation():setSpriteDirection(sprite.followers[i], direction)
  end
end

function ChangeMap(map, warp)
  local playerId = getPlayerSprite()
  local playerSprite = getSprite(playerId)
  local direction = playerSprite.dir

  playerSprite.controllable = false
  FadeToBlack(150)
  loadMap(map)
  character():transplantParty(playerId, getWarpPoint(warp), direction)

  coroutine.yield()
  RemoveFadeout(150)
  playerSprite.controllable = true
end

function CreateAnimatedSpriteAtPosition(alias, character, x, y, animName, direction, layer)
  local spriteId = emplaceSprite(alias)
  transform():initSprite(spriteId, x, y, layer)
  animation():initSprite(spriteId, "../res/sprites/" .. character .. "_anim.txt")
  animation():setSpriteDirection(spriteId, direction)
  animation():setSpriteAnimation(spriteId, animName)
end

function DestroyNamedSprite(alias)
  local spriteId = getSpriteByAlias(alias)
  destroySprite(spriteId)
end

function AliasForSpriteExpression(spriteName)
  return "expression (" .. spriteName .. ")"
end

function ShowExpression(spriteName, expression)
  local spriteId = getSpriteByAlias(spriteName)
  local sprite = getSprite(spriteId)
  local animFrame = sprite:getCurrentFrame()
  local x = sprite.loc:x()
  local y = sprite.loc:y() - animFrame.center:y()

  CreateAnimatedSpriteAtPosition(AliasForSpriteExpression(spriteName), "expression", x, y, expression, Direction.DOWN, SpriteLayer.ABOVE)
end

function RemoveExpression(spriteName)
  DestroyNamedSprite(AliasForSpriteExpression(spriteName))
end