-- Forge tutorial 4, "A shoot-em-up":  a new game with no gravity, a ship on the keys, shots,
-- rocks from spawners, health and death, lives, and game over.  Starts from New game.
TUTORIAL = { number = 4, name = "04-shmup", tag = "TUTORIAL4" }
dofile("testScripts/tutorialDrive.singe")

local frames = 0
local stage  = 0
local game   = nil

tutorialBegin(nil)


local function lightType(name)
	local names = {}
	local from, to = 1, 1

	for typeName in pairs(FORGE.game.types) do
		names[#names + 1] = typeName
	end
	table.sort(names)
	for at, typeName in ipairs(names) do
		if typeName == FORGE.typeName then
			from = at
		end
		if typeName == name then
			to = at
		end
	end
	for _ = 1, math.abs(to - from) do
		key((to > from) and SCANCODE.DOWN or SCANCODE.UP)
	end
end


local function ruleGo(index, part)
	local guard = 0

	while ((FORGE.rule ~= index) or (FORGE.part ~= (part or 0))) and (guard < 60) do
		local past = (FORGE.rule > index) or ((FORGE.rule == index) and (FORGE.part > (part or 0)))

		key(past and SCANCODE.UP or SCANCODE.DOWN)
		guard = guard + 1
	end
end


local function kitType(name, file)
	key(SCANCODE.MAIN_2)
	key(SCANCODE.A)
	form("name", name)
	form("look", "sprite")
	form("look.file", file)
end


local function place(x, y)
	key(SCANCODE.MAIN_1)
	key(SCANCODE.A)
	local entry = forgeRoom().entities[FORGE.selected]

	forgePress(entry.x, entry.y)
	forgeDrag(x, y)
	forgeRelease()
end


-- A rule from scratch:  N, its note, E and its event, then the filter fields.
local function rule(note, on, filters)
	key(SCANCODE.N)
	form("note", note)
	key(SCANCODE.E)
	pick(on)
	for _, pair in ipairs(filters or {}) do
		form(pair[1], pair[2])
	end
end


-- A part:  C or T, its name, and its fields.
local function part(partKey, name, fields)
	key(partKey)
	pick(name)
	for _, pair in ipairs(fields or {}) do
		form(pair[1], pair[2])
	end
end


local function step()
	if stage == 1 then
		-- Clear the starter:  the hero and the ground go, types and all, and so do their rules.
		key(SCANCODE.MAIN_1)
		selectEntity("hero")
		key(SCANCODE.DELETE)
		selectEntity("ground")
		key(SCANCODE.DELETE)
		key(SCANCODE.MAIN_2)
		lightType("hero")
		key(SCANCODE.DELETE)
		lightType("ground")
		key(SCANCODE.DELETE)
		key(SCANCODE.MAIN_3)
		ruleGo(1, 0)
		key(SCANCODE.DELETE)
		key(SCANCODE.DELETE)
		key(SCANCODE.DELETE)
		-- The game itself:  no world, so no gravity;  lives to lose.
		key(SCANCODE.MAIN_1)
		forgeSelect(nil)
		form("title", "Rocks")
		form("vars", "score=0, lives=3")
		form("layers", "overlay")
		tutorialShot("cleared")

	elseif stage == 2 then
		kitType("ship", "ship.png")
		form("vars", "health=1")
		form("behaviours", "keys, mover, shooter, health, sound")
		form("keys.left", "LEFT")
		form("keys.right", "RIGHT")
		form("keys.up", "UP")
		form("keys.down", "DOWN")
		form("keys.fire", "SPACE")
		form("mover.speed", 260)
		form("mover.clamp", "true")
		form("shooter.spawns", "shot")
		form("shooter.rate", 0.15)
		form("shooter.offsetY", -14)
		form("health.max", 1)
		form("health.keep", "true")
		form("sound.hit", "hit.wav")
		tutorialShot("ship")

	elseif stage == 3 then
		kitType("shot", "shot.png")
		form("behaviours", "projectile, sound")
		form("projectile.vy", -520)
		form("projectile.life", 3)
		form("sound.spawn", "shot.wav")
		kitType("rock", "rock.png")
		form("vars", "health=2")
		form("behaviours", "drift, health, sound")
		form("drift.vy", 90)
		form("health.max", 2)
		form("sound.death", "hit.wav")
		key(SCANCODE.A)
		form("name", "hive")
		form("look", "none")
		form("behaviours", "spawner")
		form("spawner.spawns", "rock")
		form("spawner.every", 0.6)
		form("spawner.max", 6)
		form("spawner.total", 12)
		tutorialShot("types")

	elseif stage == 4 then
		lightType("ship")
		place(360, 420)
		key(SCANCODE.MAIN_2)
		lightType("hive")
		place(360, 20)
		key(SCANCODE.D)
		forgePress(380, 40)
		forgeDrag(560, 20)
		forgeRelease()
		tutorialShot("placed")

	elseif stage == 5 then
		key(SCANCODE.MAIN_3)
		rule("A shot lands on a rock", "collision", { { "a", "shot" }, { "b", "rock" } })
		part(SCANCODE.T, "destroy", {})
		part(SCANCODE.T, "damage", { { "entity", "other" }, { "amount", 1 } })
		part(SCANCODE.T, "addScore", { { "amount", 10 } })
		rule("A rock dies", "death", { { "type", "rock" } })
		part(SCANCODE.T, "emit", { { "count", 24 }, { "r", 255 }, { "g", 120 }, { "b", 60 } })
		part(SCANCODE.T, "addScore", { { "amount", 50 } })
		tutorialShot("hitRule")

	elseif stage == 6 then
		rule("A rock rams the ship", "collision", { { "a", "rock" }, { "b", "ship" } })
		part(SCANCODE.T, "destroy", {})
		part(SCANCODE.T, "damage", { { "entity", "other" }, { "amount", 1 } })
		rule("The ship is lost", "death", { { "type", "ship" } })
		part(SCANCODE.T, "addVar", { { "name", "lives" }, { "amount", -1 } })
		clear("entity")
		part(SCANCODE.T, "flash", { { "r", 255 }, { "g", 60 }, { "b", 60 }, { "seconds", 0.3 } })
		part(SCANCODE.T, "setVar", { { "name", "health" }, { "value", "1" } })
		part(SCANCODE.T, "moveTo", { { "x", 360 }, { "y", 420 } })
		rule("Out of lives", "frame", {})
		part(SCANCODE.C, "test", { { "expr", "lives <= 0" } })
		part(SCANCODE.T, "gameOver", {})
		rule("A rock slips past the bottom", "frame", { { "each", "rock" } })
		part(SCANCODE.C, "test", { { "expr", "self.y > 500" } })
		part(SCANCODE.T, "destroy", {})
		-- The readout, kept from the starter, says the lives too.
		ruleGo(1, 1)
		form("text", '"score " .. score .. "  lives " .. lives')
		tutorialShot("rules")

	elseif stage == 7 then
		key(SCANCODE.S)
		local built = tutorialEnd()
		local mine  = onOverlayUpdate

		dofile(built)
		game            = onOverlayUpdate
		onOverlayUpdate = mine
		authorKeyDown(0, SCANCODE.SPACE.value)

	elseif stage == 19 then
		tutorialShot("playing")
		debugPrint(string.format("%s after firing a while:  score %s, lives %s, %d rocks, %d shots", TUTORIAL.tag, tostring(AUTHOR_VARS.score), tostring(AUTHOR_VARS.lives), authorCount("rock"), authorCount("shot")))
	elseif stage == 20 then
		debugPrint(TUTORIAL.tag .. " RESULT done")
		singeQuit()
	end
end


function onOverlayUpdate()
	frames = frames + 1
	if frames % 12 == 0 and stage < 20 then
		stage = stage + 1
		step()
	end
	if game ~= nil then
		return game()
	end
	forgeDraw(nil, nil)

	return OVERLAY_UPDATED
end