-- Convert a pre-flat-schema room save into the current { objects = { ... } }
-- format.  Usage:
--   lua tools/migrate_legacy_room.lua legacy.sav migrated.sav

local inputPath, outputPath = arg[1], arg[2]
assert(inputPath and outputPath, "usage: lua tools/migrate_legacy_room.lua legacy.sav migrated.sav")

local input = assert(io.open(inputPath, "r"))
local chunk, err = load("return " .. input:read("*a"))
input:close()
assert(chunk, err)
local legacy = chunk()

local objects = {}
local function append(class, object, includeColor)
	local converted = {
		class = class,
		x = object.x,
		y = object.y,
	}
	if includeColor ~= false then converted.color = object.color end
	table.insert(objects, converted)
end

for _, color in ipairs({ "red", "green", "blue" }) do
	for _, object in ipairs(legacy.players[color] or {}) do append("player", object) end
	-- Doors are shared between color layers in the current schema, so they have
	-- no color field when serialized.
	for _, object in ipairs(legacy.doors[color] or {}) do append("door", object, false) end
	for _, object in ipairs(legacy.static_walls[color] or {}) do append("static_wall", object) end
	-- The legacy wall sprite was renamed to box when assets became data-driven.
	for _, object in ipairs(legacy.walls[color] or {}) do append("box", object) end
	for _, object in ipairs(legacy.switches[color] or {}) do append("switch", object) end
end

for _, sage in pairs(legacy.sages or {}) do
	table.insert(objects, { class = "npc", x = sage.x, y = sage.y })
end

require "libs/TSerial"
local output = assert(io.open(outputPath, "w"))
output:write(TSerial.pack({ objects = objects }, nil, true))
output:close()