#!/usr/bin/env lua5.3
basepath = (debug.getinfo(1, "S").source:sub(2):match("(.*[/\\])") or "./"):sub(1,-2)
package.path = basepath .. "/src/?.lua;" ..basepath .. "/src/?/init.lua" .. ";" .. package.path
local toml = require "toml"

local typesIn = {
	["__unknown"] = "lua_touserdata",
	["char"] = "luaL_checkinteger",
	["int"] = "luaL_checkinteger",
	["float"] = "luaL_checknumber",
	["long long"] = "luaL_checkinteger",
	["unsigned char"] = "luaL_checkinteger",
	["char *"] = "(char *)luaL_checkstring"
}

local typesOut = {
	["__unknown"] = "lua_pushlightuserdata",
	["char"] = "lua_pushinteger",
	["int"] = "lua_pushinteger",
	["long long"] = "lua_pushinteger",
	["unsigned char"] = "lua_pushinteger",
	["char *"] = "lua_pushstring"
}

local function readFile(path)
	local file = io.open(path,"rb")
	local output = file:read("*a")
	file:close()
	return output
end

local function bp(path)
	return basepath .. "/" .. path
end

local function stringJoin(lst,sep)
	local nstring = ""
	for _,str in ipairs(lst) do
		nstring = nstring .. sep .. str
	end
	return string.sub(nstring,1 + string.len(sep))
end

local statics = toml.parse(readFile(bp("src/values/statics.toml")))
local functions = toml.parse(readFile(bp("src/values/functions.toml")))
local ofile = io.open(bp("src/lua.c"),"wb")

local supportedTarget = false
if os.getenv("target_os") == "linux" then
	ofile:write([[
#include <lua5.3/lua.h>
#include <lua5.3/lualib.h>
#include <lua5.3/lauxlib.h>
]])
	supportedTarget = true
end

if os.getenv("target_os") == "openbsd" then
	ofile:write([[
#include <lua-5.3/lua.h>
#include <lua-5.3/lualib.h>
#include <lua-5.3/lauxlib.h>
]])
	supportedTarget = true
end

if os.getenv("target_os") == "windows" then
	ofile:write([[
#include <lua.h>
#include <lualib.h>
#include <lauxlib.h>
]])
	supportedTarget = true
end

if supportedTarget == false then
	print("Platform " ..tostring(os.getenv("target_os")).. " unsupported by lua_translate.")
	os.exit(1)
end

ofile:write([[
lua_State * engine_lua_state;
#include "lua_manual.c"

]])

for func,_ in pairs(functions) do
	if functions[func].lua == "no" or
	   functions[func].lua == "manual" then
		goto continue
	end
	
	local invarCount = 1
	local funcnew,_ = string.gsub(func,"engine_","",1)
	funcnew = "engine_luaf_" ..funcnew
	ofile:write('int ' ..funcnew.. '(lua_State *L) {\n')
	for _,arg in ipairs(functions[func].arguments) do
		local checkfunc = false
		if typesIn[arg] == nil then
			checkfunc = typesIn.__unknown
		else
			checkfunc = typesIn[arg]
		end
		ofile:write('\t' ..arg.. ' ' ..functions[func].argNames[invarCount].. ' = ' ..checkfunc.. '(L,' ..tostring(invarCount).. ');\n')
		invarCount = invarCount + 1
	end
	
	local argstring = "(" ..stringJoin(functions[func].argNames,",").. ")"
	
	local outtype = functions[func].type
	if outtype == "void" then
		ofile:write('\t' .. func .. argstring .. ";")
		ofile:write('\n\treturn 0;')
	else
		local pushfunc = false
		if typesOut[outtype] == nil then
			pushfunc = typesOut.__unknown
		else
			pushfunc = typesOut[outtype]
		end
		
		ofile:write('\t' ..outtype.. ' outvar = ' ..func .. argstring.. ';')
		ofile:write('\n\t' ..pushfunc.. '(L,outvar);')
		ofile:write('\n\treturn 1;')
	end
	
	ofile:write('\n}\n\n')
	::continue::
end

ofile:write([[
void engine_lua_init() {
	engine_lua_state = luaL_newstate();
	luaL_openlibs(engine_lua_state);

]])

for static,_ in pairs(statics) do
	ofile:write('\tlua_pushinteger(engine_lua_state,' ..static.. ');\n')
	ofile:write('\tlua_setglobal(engine_lua_state,"' ..static.. '");\n')
end

for func,_ in pairs(functions) do
	if functions[func].lua == "no" or
	   functions[func].lua == "manual" then
		goto continue
	end
	
	local funcnew,_ = string.gsub(func,"engine_","",1)
	funcnew = "engine_luaf_" ..funcnew
	ofile:write('\tlua_pushcfunction(engine_lua_state,' ..funcnew.. ');\n')
	ofile:write('\tlua_setglobal    (engine_lua_state,"' ..func.. '");\n')
	::continue::
end

ofile:write([[
	engine_lua_init_manual();
	luaL_loadfile(engine_lua_state,"mods/main/script/main.lua");
	lua_call(engine_lua_state,0,0);
}]])

ofile:close()