-- What the tutorial scenes share:  the keys a reader presses, pressed the same way, and the two
-- checks every tutorial ends on.  A tutorial in docs/Forge.adoc names keys;  its scene presses
-- them through here, so the text and the test cannot drift apart without the sweep saying so.
--
-- A scene sets TUTORIAL (its number and name) before loading this, and calls tutorialBegin to
-- open a description, tutorialShot to take a named picture, and tutorialEnd to check the result
-- against the shipped description and run the built game.
FORGE_LIBRARY = true
dofile("Forge/Forge.singe")

local font = fontLoad("Singe/FreeSansBold.ttf", 15)

fontSelect(font)
fontQuality(FONT_QUALITY_BLENDED)
overlaySetResolution(720, 480)

TUTORIAL_OUT = singeGetDataPath()


-- The engine hands onKeyPressed two integers;  so does this.
function key(code, character)
	forgeKey(character or 0, code.value)
end


-- Types text as a person would, one character at a time.
function typeText(text)
	for at = 1, #text do
		forgeKey(string.byte(text, at), 0)
	end
end


-- ENTER until the field is the one being edited.  Answers whether it was reached.
local function reach(field)
	local guard = 0

	while (FORGE.lastField ~= field) and (guard < 40) do
		key(SCANCODE.RETURN)
		guard = guard + 1
	end
	if FORGE.lastField ~= field then
		debugPrint(string.format("%s FAIL the form never reached %s", TUTORIAL.tag, field))
		return false
	end

	return true
end


-- ESC out of the form:  off a list first, then off the field it left being typed.
local function leave()
	if FORGE.picker ~= nil then
		key(SCANCODE.ESCAPE)
	end
	if FORGE.editing ~= nil then
		key(SCANCODE.ESCAPE)
	end
end


-- Fills in one field of the form ENTER walks:  ENTER until the field is the one being edited,
-- type the value, ENTER to keep it, ESC to leave the form.  Exactly the keys the text names.
-- A field with a list narrows it to the value and takes it, which moves on to the next field.
function form(field, value)
	if not reach(field) then
		return
	end
	if FORGE.picker ~= nil then
		pick(value)
	else
		typeText(tostring(value))
		key(SCANCODE.RETURN)
	end
	leave()
end


-- Empties one field of the form:  ENTER until it is the one being edited, DELETE, ESC.
function clear(field)
	if not reach(field) then
		return
	end
	if FORGE.picker ~= nil then
		pick("(none)")
	else
		key(SCANCODE.DELETE)
	end
	leave()
end


-- Narrows the picker by typing and takes the first match.
function pick(name)
	typeText(name)
	key(SCANCODE.RETURN)
end


-- Selects the entity with an id, in the entities panel.
function selectEntity(id)
	for index, entry in ipairs(forgeRoom().entities) do
		if entry.id == id then
			forgeSelect(index)
			return
		end
	end
	debugPrint(string.format("%s FAIL no entity called %s", TUTORIAL.tag, id))
end


-- Puts the panel on a mode, by TAB as a reader would.
function panel(mode)
	local guard = 0

	while (FORGE.mode ~= mode) and (guard < 6) do
		key(SCANCODE.TAB)
		guard = guard + 1
	end
end


-- A picture for the book, drawn now and named.
function tutorialShot(name)
	singeScreenshot(string.format("%02d-%s", TUTORIAL.number, name))
end


-- Opens the tutorial's working copy:  a fresh New game, or the previous tutorial's shipped
-- description, so each starts where the last left off.
function tutorialBegin(fromShipped)
	local work = TUTORIAL_OUT .. TUTORIAL.name .. ".game"

	if fromShipped then
		if not authorCopy("Forge/tutorials/" .. fromShipped .. ".game", work) then
			debugPrint(TUTORIAL.tag .. " FAIL could not copy " .. fromShipped)
			singeQuit()
		end
	else
		authorSave(forgeTemplate(), work)
	end
	if not forgeBegin(work) then
		debugPrint(TUTORIAL.tag .. " FAIL could not open " .. work)
		singeQuit()
	end

	return work
end


-- The two checks:  what the keys made equals the shipped description, compiled;  and the game it
-- makes runs.  A shipped description that is not there yet is written, so a new tutorial's scene
-- produces the file the book ships, and the next run checks against it.
function tutorialEnd()
	local shipped = "Forge/tutorials/" .. TUTORIAL.name .. ".game"
	local built

	forgeSave()
	-- The compiled header names the description's file, which a release has set and a shipped
	-- copy has not;  the comparison is of the game, not of where it came from.
	FORGE.game.source = nil
	if lfs.attributes(shipped, "mode") ~= "file" then
		authorCopy(FORGE.path, TUTORIAL_OUT .. TUTORIAL.name .. ".shipped.game")
		debugPrint(TUTORIAL.tag .. " WROTE " .. TUTORIAL_OUT .. TUTORIAL.name .. ".shipped.game -- copy it to " .. shipped)
	else
		local mine   = authorCompile(FORGE.game)
		local theirs = authorCompile(authorLoad(shipped))

		if mine == theirs then
			debugPrint(TUTORIAL.tag .. " the keys made the shipped description")
		else
			local out = assert(io.open(TUTORIAL_OUT .. TUTORIAL.name .. ".mine.singe", "w"))

			out:write(mine)
			out:close()
			out = assert(io.open(TUTORIAL_OUT .. TUTORIAL.name .. ".theirs.singe", "w"))
			out:write(theirs)
			out:close()
			debugPrint(TUTORIAL.tag .. " FAIL the keys made something else;  see " .. TUTORIAL_OUT .. TUTORIAL.name .. ".mine.singe")
		end
	end
	built = forgeBuild(TUTORIAL_OUT .. TUTORIAL.name .. ".singe")
	forgeClose()

	return built
end