--[[
 *
 *  Singe 3
 *  Copyright (C) 2006-2026 Scott Duensing <scott@kangaroopunch.com>
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 3
 * of the License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
 * 02110-1301, USA.
 *
 *
--]]



-- The master service, from the cabinet's side.
--
-- One place that knows the server address, the signed-in account and the player's name, so the menu
-- and every game agree about them.  It lives in the data root rather than a game's own directory
-- because an account belongs to the machine:  a game posting a score needs the same token the menu
-- signed in with.
--
-- Everything here is asynchronous -- see Singe/Net.singe for why -- so every call takes a function
-- and calls it back.  masterPump() must run once a frame for any of it to make progress.


dofile("Singe/Net.singe")

local cjson = require("cjson")

MASTER_DEFAULT_URL = "https://master.singeengine.com"

MASTER = {
	url    = MASTER_DEFAULT_URL,
	token  = nil,
	email  = nil,
	name   = nil,
	queue  = {},     -- scores waiting for a connection
}

local settingsPath = nil
local flushing     = false
local lastFlush    = 0
local flushDue     = false
local FLUSH_EVERY  = 30000


local function path()
	if not settingsPath then
		settingsPath = singeGetSystemInfo().dataRoot .. "master.dat"
	end
	return settingsPath
end


function masterLoad()
	local file = io.open(path(), "r")

	if not file then
		return
	end
	local text = file:read("*a")
	file:close()
	local ok, stored = pcall(cjson.decode, text)
	if ok and type(stored) == "table" then
		MASTER.url   = stored.url or MASTER_DEFAULT_URL
		MASTER.token = stored.token
		MASTER.email = stored.email
		MASTER.name  = stored.name
		MASTER.queue = stored.queue or {}
	end
end


function masterSave()
	local file = io.open(path(), "w")

	if not file then
		return false
	end
	file:write(cjson.encode({ url = MASTER.url, token = MASTER.token, email = MASTER.email,
							  name = MASTER.name, queue = MASTER.queue }))
	file:close()
	return true
end


function masterSignedIn()
	return MASTER.token ~= nil
end


-- Every call goes through here so the token, the content type and the JSON decoding are in one
-- place, and so a 401 always means the same thing:  whatever we were holding is no longer a
-- session, and pretending otherwise only produces a second failure later.
local function request(method, endpoint, body, onDone, opts)
	opts = opts or {}
	local headers = { ["Content-Type"] = "application/json" }

	if MASTER.token and not opts.anonymous then
		headers["Authorization"] = "Bearer " .. MASTER.token
	end
	netRequest({
		url = MASTER.url .. endpoint, method = method, headers = headers,
		body = body and cjson.encode(body) or nil,
		toFile = opts.toFile, onProgress = opts.onProgress,
	}, function(ok, result)
		if not ok then
			return onDone(false, result.error)
		end
		local parsed = {}
		if result.body and result.body ~= "" then
			local decoded, value = pcall(cjson.decode, result.body)
			if decoded and type(value) == "table" then
				parsed = value
			end
		end
		if result.status == 401 and not opts.anonymous then
			MASTER.token = nil
			masterSave()
			return onDone(false, "signed out by the server", parsed, result)
		end
		if result.status >= 400 then
			return onDone(false, parsed.message or ("the server said " .. result.status), parsed, result)
		end
		onDone(true, parsed, parsed, result)
	end)
end


MASTER_REQUEST = request


function masterSignIn(email, password, onDone)
	request("POST", "/v1/account/login", { email = email, password = password }, function(ok, reply)
		if not ok then
			return onDone(false, reply)
		end
		MASTER.token = reply.token
		MASTER.email = reply.email
		masterSave()
		-- The display name is not part of signing in, so it is fetched once and kept:  a game
		-- about to post a score should not have to discover it has none mid-play.
		masterWhoAmI(function() end)
		onDone(true, reply)
	end, { anonymous = true })
end


function masterRegister(email, password, onDone)
	request("POST", "/v1/account/register", { email = email, password = password }, onDone, { anonymous = true })
end


function masterRecover(email, onDone)
	request("POST", "/v1/account/recover", { email = email }, onDone, { anonymous = true })
end


function masterSignOut(onDone)
	local had = MASTER.token

	MASTER.token = nil
	MASTER.email = nil
	MASTER.name  = nil
	masterSave()
	if had then
		-- Told after the fact:  the cabinet is signed out either way, and a server that cannot be
		-- reached must not leave somebody looking signed in.
		MASTER.token = had
		request("POST", "/v1/account/logout", nil, function() end)
		MASTER.token = nil
	end
	if onDone then onDone(true) end
end


function masterWhoAmI(onDone)
	request("GET", "/v1/account", nil, function(ok, reply)
		if ok then
			MASTER.email = reply.email or MASTER.email
			masterSave()
		end
		onDone(ok, reply)
	end)
end


function masterSetName(name, onDone)
	request("POST", "/v1/player/name", { name = name }, function(ok, reply)
		if ok then
			MASTER.name = reply.name
			masterSave()
		end
		onDone(ok, reply)
	end)
end


function masterCatalogue(onDone)
	request("GET", "/v1/catalogue", nil, function(ok, reply)
		if ok then
			for _, game in ipairs(reply.games or {}) do
				game.version   = game.version and math.floor(game.version) or nil
				game.installed = game.installed and math.floor(game.installed) or nil
				game.size      = game.size and math.floor(game.size) or nil
			end
		end
		onDone(ok, ok and reply.games or reply)
	end)
end


-- Download a game to a file and check it against the digest the catalogue published.  A download
-- that arrives wrong is worse than one that fails:  it installs, and then does not run.
function masterDownload(gameId, version, toFile, expectSha, onProgress, onDone)
	-- JSON has one number type and Lua 5.4 has two, so a version that went out as 1 comes back as
	-- 1.0 and would build a path ending "/1.0" that the service does not recognise.
	local path = string.format("/v1/download/%s/%d", gameId, math.floor(version))

	request("GET", path, nil, function(ok, reply, _, result)
		if not ok then
			return onDone(false, reply)
		end
		local file = io.open(toFile, "rb")
		if not file then
			return onDone(false, "the download did not land on disk")
		end
		local bytes = file:read("*a")
		file:close()
		if expectSha and utilSha256(bytes) ~= expectSha then
			os.remove(toFile)
			return onDone(false, "the download did not match its published checksum")
		end
		onDone(true, { bytes = #bytes, file = toFile })
	end, { toFile = toFile, onProgress = onProgress })
end


function masterTellInstalled(gameId, version, onDone)
	request("POST", "/v1/installed", { game = gameId, version = version and math.floor(version) or nil },
		onDone or function() end)
end


function masterBoard(gameId, board, onDone)
	request("GET", "/v1/scores/" .. gameId .. (board and ("?board=" .. board) or ""), nil, function(ok, reply)
		-- JSON has one number type and Lua 5.4 has two, so a score that went out as 4242 comes back
		-- as 4242.0 and would be shown to a player with a decimal point on it.
		if ok then
			for _, row in ipairs(reply.top or {}) do
				row.value = math.floor(row.value)
				row.at    = row.at and math.floor(row.at) or nil
			end
			if reply.standing then
				reply.standing.value   = math.floor(reply.standing.value)
				reply.standing.rank    = math.floor(reply.standing.rank)
				reply.standing.players = math.floor(reply.standing.players)
			end
		end
		onDone(ok, reply)
	end)
end


-- A score is queued first and sent afterwards.  A cabinet is often offline, and a game must never
-- wait on the wire to show its own board;  the queue is written to disk so a power cut between the
-- play and the send does not lose it.
-- Tell the service a play is starting.  What comes back travels with the score, so the server can
-- say how long the play took by its own clock;  a cabinet that is offline simply has no play id and
-- the score carries no time, which is honest rather than broken.
function masterPlayStart(gameId, onDone)
	if not masterSignedIn() then
		MASTER.play = nil
		if onDone then onDone(false, "not signed in") end
		return
	end
	request("POST", "/v1/play/start", { game = gameId }, function(ok, reply)
		MASTER.play = ok and reply.play and math.floor(reply.play) or nil
		if onDone then onDone(ok, reply) end
	end)
end


function masterSubmitScore(gameId, value, board, meta)
	MASTER.queue[#MASTER.queue + 1] = { game = gameId, value = math.floor(value),
										board = board or "default", meta = meta,
										play = MASTER.play }
	masterSave()
	-- Send it on the next pump rather than waiting out the retry interval:  a player who has just
	-- finished wants to see themselves on the board, and the interval exists for retrying what
	-- failed, not for delaying what has not been tried.  This is a flag rather than a timestamp:
	-- singeGetTicks() counts from engine start, so "lastFlush = 0" would mean "once the engine has
	-- been up FLUSH_EVERY", which early in a run is never.
	flushDue = true
end


function masterQueueLength()
	return #MASTER.queue
end


-- Hand the queue to the server one at a time.  A refusal that is the score's own fault (the game is
-- unknown, the value is nonsense) drops it, because retrying it forever would block everything
-- behind it;  anything else leaves it in place to try again.
local function flushQueue()
	if flushing or #MASTER.queue == 0 or not MASTER.token then
		return
	end
	flushing = true
	local entry = MASTER.queue[1]
	request("POST", "/v1/scores/" .. entry.game, { value = entry.value, board = entry.board, meta = entry.meta, play = entry.play },
		function(ok, reply, parsed, result)
			local status = result and result.status or 0
			if ok or (status >= 400 and status < 500 and status ~= 429) then
				table.remove(MASTER.queue, 1)
				masterSave()
				-- A backlog should drain, not trickle out one per interval.
				if #MASTER.queue > 0 then
					flushDue = true
				end
			end
			flushing = false
		end)
end


function masterPump()
	netPump()
	if flushDue or (singeGetTicks() - lastFlush > FLUSH_EVERY) then
		flushDue  = false
		lastFlush = singeGetTicks()
		flushQueue()
	end
end


masterLoad()