#import("util")
#import("compiler.lua53")
#import("compiler.luajit")
#import("lua-parser.scope")
#import("lua-parser.validator")
#import("lua-parser.pp")
#import("lua-parser.parser")
#import("cmdline")

local util = require("util")

local candran = {
	VERSION = "0.2.0"
}

--- Run the preprocessor
-- @tparam input string input code
-- @tparam args table arguments for the preprocessor. They will be inserted into the preprocessor environement.
-- @treturn output string output code
function candran.preprocess(input, args={})
	-- generate preprocessor code
	local preprocessor = ""
	for line in (input.."\n"):gmatch("(.-\n)") do
		if line:match("^%s*#") and not line:match("^#!") then -- exclude shebang
			preprocessor ..= line:gsub("^%s*#", "")
		else
			preprocessor ..= ("write(%q)"):format(line:sub(1, -2)) .. "\n"
		end
	end
	preprocessor ..= "return output"

	-- make preprocessor environement
	local env = {}
	for k,v in pairs(_G) do
		env[k] = v
	end
	for k, v in pairs(args) do
		env[k] = v
	end
	--- Candran library table
	env.candran = candran
	--- Current preprocessor output
	env.output = ""
	--- Import an external Candran/Lua module into the generated file
	-- @tparam modpath string module path
	-- @tparam margs table preprocessor arguments to use when preprocessessing the module
	-- @tparam autoRequire[opt=true] boolean true to automatically load the module into a local variable
	env.import = function(modpath, margs=args, autoRequire=true)
		local filepath = assert(util.search(modpath), "No module named \""..modpath.."\"")

		-- open module file
		local f = io.open(filepath)
		if not f then error("Can't open the module file to import") end
		for k, v in pairs(args) do
			if margs[k] == nil then margs[k] = v end
		end
		local modcontent = candran.preprocess(f:read("*a"), margs)
		f:close()

		-- get module name (ex: module name of path.to.module is module)
		local modname = modpath:match("[^%.]+$")

		env.write(
			"-- MODULE \""..modpath.."\" --\n"..
			"local function _()\n"..
				modcontent.."\n"..
			"end\n"..
			(autoRequire and "local "..modname.." = _() or "..modname.."\n" or "").. -- auto require
			"package.loaded[\""..modpath.."\"] = "..(autoRequire and modname or "_()").." or true\n".. -- add to package.loaded
			"-- END OF MODULE \""..modpath.."\" --"
		)
	end
	--- Include another file content in the preprocessor output.
	-- @tparam file string filepath
	env.include = function(file)
		local f = io.open(file)
		if not f then error("Can't open the file "..file.." to include") end
		env.write(f:read("*a"))
		f:close()
	end
	--- Write a line in the preprocessor output.
	-- @tparam ... string strings to write (similar to print)
	env.write = function(...)
		env.output ..= table.concat({...}, "\t") .. "\n"
	end
	--- Will be replaced with the content of the variable with the given name, if it exists.
	-- @tparam name string variable name
	env.placeholder = function(name)
		if env[name] then
			env.write(env[name])
		end
	end

	-- compile & load preprocessor
	local preprocess, err = util.loadenv(candran.compile(preprocessor, args.target), "candran preprocessor", env)
	if not preprocess then error("Error while creating Candran preprocessor: " .. err) end

	-- execute preprocessor
	local success, output = pcall(preprocess)
	if not success then error("Error while preprocessing file: " .. output .. "\nWith preprocessor : \n" .. preprocessor) end

	return output
end

-- Compiler
function candran.compile(input, target="lua53")
	local parse = require("lua-parser.parser").parse

	local ast, errmsg = parse(input, "candran")

	if not ast then
		error("Compiler: error while parsing file: "..errmsg)
	end

	return require("compiler."..target)(ast)
end

-- Preprocess & compile
function candran.make(code, args={})
	return candran.compile(candran.preprocess(code, args), args.target)
end

function candran.searcher(modpath)
	-- get module filepath
	local notfound = ""
	local filepath
	for path in package.path:gsub("%.lua", ".can"):gmatch("[^;]+") do
		local path = path:gsub("%?", (modpath:gsub("%.", "/")))
		local f = io.open(path)
		if f then
			f:close()
			filepath = path
		else
			notfound = notfound .. "\n\tno Candran file '"..path.."'"
		end
	end
	if not filepath then return notfound end

	-- open module file
	local f = io.open(filepath)
	if not f then error("Can't open the module file to import") end
	local modcontent = f:read("*a")
	f:close()

	return load(candran.make(modcontent))
end

return candran