include, plotscr.hsd
include, scancode.hsi

global variable(1, armada)
global variable(2, playing)
global variable(3, direction)
global variable(4, movespeed)
global variable(5, walktoggle)
global variable(6, shooter)
global variable(7, friendly bullets)
global variable(8, cannon charge)
global variable(9, start speed)
global variable(10, enemy bullets)
global variable(11, enemy fire rate)
global variable(12, score)

plotscript, space invadeOHRs, begin
  suspend player
  create armada
  create shooter
  create bullet layers
  start timer scripts
  setup score
  playing := true
  while(playing) do(
    update game
    wait(1)
  )
  cleanup all
  game over
end

script, cleanup all, begin
  # Free all slices and reset their globals to zero
  free slice(armada)
  armada := 0
  free slice(shooter)
  shooter := 0
  free slice(friendly bullets)
  friendly bullets := 0
  free slice(enemy bullets)
  enemy bullets := 0
  # Cancel the timers
  stop timer(0)
  stop timer(1)
  # Hide the score string
  hide string(1)
end  

script, start timer scripts, begin
  set timer(0, 1, 3, @update walktoggle)
  set timer(1, 1, 4, @reload cannon)
end

script, create shooter, begin
  shooter := load walkabout sprite(10)
  realign slice(shooter, edge:center, edge:bottom, edge:center, edge:bottom)
end

script, create armada, begin
  if(armada) then(
    set slice x(armada, 0)
    set slice y(armada, 0)
  )else(
    armada := create container
  )
  variable(sl, row, col)
  for(row, 0, 3) do(
    for(col, 0, 7) do(
      sl := load walkabout sprite(2 + col)
      set parent(sl, armada)
      set sprite frame(sl, 4)
      place sprite(sl, col * 25, row * 25)
    )
  )
  refit armada
  direction := 1
  start speed += 1
  movespeed := start speed
  enemy fire rate += 1
end

script, create bullet layers, begin
  friendly bullets := create container(320, 200)
  enemy bullets := create container(320, 200)
end

script, setup score, begin
  show string at(1, 0, 0)
  $1=""
  append number(1, score)
end

script, update game, begin
  user input
  move armada
  update each enemy
  update shooter
  update bullets
end

script, user input, begin
  if(key is pressed(key:ESC)) then(
    playing := false
  )
  if(key is pressed(key:left)) then(
    set slice x(shooter, slice x(shooter) -- 4)
  )
  if(key is pressed(key:right)) then(
    set slice x(shooter, slice x(shooter) + 4)
  )
  if(keyval(key:space)>>1) then(
    fire bullet
  )
end

script, move armada, begin
  set slice x(armada, slice x(armada) + (movespeed * direction))
  if(direction==1) then(
    if(not(slice contains(sprite layer, armada))) then(
      clamp slice(armada, sprite layer)
      play sound(0)
      direction := direction * -1
      set slice y(armada, slice y(armada) + 4)
    )
  )else(
    if(not(slice contains(sprite layer,armada))) then(
      clamp slice(armada, sprite layer)
      play sound(0)
      direction := direction * -1
      movespeed += 1
      set slice y(armada, slice y(armada) + 4)
    )
  )
  if(slice y(armada) + slice height(armada) >> slice height(sprite layer)) then(
    shooter dies
  )
end

script, update each enemy, begin
  variable(enemy)
  enemy := first child(armada)
  if(not(enemy)) then(create armada, exit script)
  while(enemy) do(
    set sprite frame(enemy, 4 + walktoggle)
    if(slice collide(enemy, shooter)) then(shooter dies)
    if(random(0,999) << enemy fire rate) then(enemy fire bullet(enemy))
    enemy := next sibling(enemy)
  )
end

script, update shooter, begin
  set sprite frame(shooter, walktoggle)
end

script, update bullets, begin
  update friendly bullets
  update enemy bullets
end

script, update friendly bullets, begin
  variable(bullet, delete)
  bullet := first child(friendly bullets)
  while(bullet) do(
    delete := false
    set slice y(bullet, slice y(bullet) -- 8)
    if(check for friendly bullet hit(bullet)) then(delete := bullet)
    if(slice collide(bullet, sprite layer) == false) then(delete := bullet)
    bullet := next sibling(bullet)
    if(delete) then(free slice(delete))
  )
end

script, check for friendly bullet hit, bullet, begin
  variable(enemy)
  enemy := first child(armada)
  while(enemy) do(
    if(slice contains(enemy, bullet)) then(
      free slice(enemy)
      play sound(3)
      refit armada
      score += move speed * enemy fire rate
      $1=""
      append number(1, score)
      exit returning(true)
    )
    enemy := next sibling(enemy)
  )
  exit returning(false)
end

script, update enemy bullets, begin
  variable(bullet, delete)
  bullet := first child(enemy bullets)
  while(bullet) do(
    delete := false
    set slice y(bullet, slice y(bullet) + 5)
    if(slice contains(shooter, bullet)) then(
      shooter dies
      exit script
    )
    if(not(slice collide(bullet, sprite layer))) then(delete := bullet)
    bullet := next sibling(bullet)
    if(delete) then(free slice(delete))
  )
end

script, fire bullet, begin
  if(cannon charge == false) then(exit script)
  variable(bullet)
  bullet := create rect(4, 8)
  set parent(bullet, friendly bullets)
  set horiz anchor(bullet, edge:center)
  set vert anchor(bullet, edge:center)
  set rect fgcol(bullet, 0)
  set rect bgcol(bullet, 15)
  set rect border(bullet, -1)
  set slice x(bullet, slice screen x(shooter))
  set slice y(bullet, slice screen y(shooter) -- slice height(shooter))
  cannon charge := false
  play sound(2)
end

script, enemy fire bullet, enemy, begin
  variable(bullet)
  bullet := create rect(4, 8)
  set parent(bullet, enemy bullets)
  set horiz anchor(bullet, edge:center)
  set vert anchor(bullet, edge:center)
  set rect fgcol(bullet, 0)
  set rect bgcol(bullet, 12)
  set rect border(bullet, -1)
  set slice x(bullet, slice screen x(enemy) + slice width(enemy) / 2)
  set slice y(bullet, slice screen y(enemy) + slice height(enemy))
  play sound(2)
end

script, update walktoggle, begin
  walktoggle := walktoggle, xor, 1
  play sound(1)
  set timer(0, 1, 3, @update walktoggle)
end

script, reload cannon, begin
  cannon charge := true
  set timer(1, 1, 5, @reload cannon)
end

script, refit armada, begin
  variable(sl, x1, y1, x2, y2, diffx, diffy)
  x1 := 99999
  y1 := 99999
  x2 := -99999
  y2 := -99999
  # Find the new boundaries
  sl := first child(armada)
  while(sl) do(
    if(slice screen x(sl) << x1) then(x1 := slice screen x(sl))
    if(slice screen y(sl) << y1) then(y1 := slice screen y(sl))
    if(slice screen x(sl) + slice width(sl) >> x2) then(x2 := slice screen x(sl) + slice width(sl))
    if(slice screen y(sl) + slice height(sl) >> y2) then(y2 := slice screen y(sl) + slice height(sl))
    sl := next sibling(sl)
  )
  # Readjust container
  diffx := x1 -- slice screen x(armada)
  diffy := y1 -- slice screen y(armada)
  set slice screen x(armada, x1)
  set slice screen y(armada, y1)
  set slice width(armada, x2 -- x1)
  set slice height(armada, y2 -- y1)
  sl := first child(armada)
  # Readjust children
  while(sl) do(
    set slice x(sl, slice x(sl) -- diffx)
    set slice y(sl, slice y(sl) -- diffy)
    sl := next sibling(sl)
  )
end

script, shooter dies, begin
  $0="GAME OVER"
  center string at(0, 160, 100)
  playing := false
  while(key is pressed(key:space)) do(wait)
end