package main

import (
	"doll/internal/log"
	"os"

	lua "github.com/yuin/gopher-lua"
)

// square multiplies number by itself.
func square(L *lua.LState) int {
	// get first (1) function argument and convert to int
	i := L.ToInt(1)

	// make calculation and cast to LNumber
	ln := lua.LNumber(i * i)

	// Push it to the stack
	L.Push(ln)

	// Notify that we pushed one value to the stack
	return 1
}

func main() {
	// Init log subsystem.
	log.Init("info", os.Stderr)

	file := "example_data/03-test.lua"

	// Load the Lua script file.
	log.Infof("Loading %s", file)

	// We can execute script directly via L.DoFile("./example_data/03-test.lua") but in practice we'll get scripts as
	// strings - snippets from templates - so, testing/checking how it works is not use for project.
	luaCode, err := os.ReadFile(file)

	if err != nil {
		log.Fatalf("Error reading Lua file %s: %s", file, err)
	}

	log.Info("Creating new Lua state")
	L := lua.NewState()
	defer L.Close()

	log.Info("Registering go function as lua built-in function")
	L.SetGlobal("square", L.NewFunction(square))

	log.Info("Evaluating Lua code")
	if err := L.DoString(string(luaCode)); err != nil {
		log.Errorf("Error evaluating Lua code: %s", err)

		os.Exit(1)
	}
}

/* vim: set ft=go noet ai ts=4 sw=4 sts=4: */