//go:build js && wasm
// +build js,wasm

package main

import (
	"bufio"
	"bytes"
	"fmt"
	"io/ioutil"
	"os"
	"runtime"
	"syscall/js"
	"varaq/varaq"
)

func main() {
	if runtime.GOARCH == "wasm" {
		done := make(chan struct{}, 0)
		js.Global().Set("varaq", js.FuncOf(jsInterpret))
		fmt.Println("varaq WASM init, Qa'pla!")
		<-done
	} else {
		argsCount := len(os.Args[1:])
		if argsCount >= 1 {
			runFile(os.Args[1])
		} else {
			repl()
		}
		os.Exit(0)
	}
}

func repl() {
	scanner := bufio.NewScanner(os.Stdin)
	for fmt.Print("> "); scanner.Scan(); fmt.Print("> ") {
		line := scanner.Text()
		if len(line) == 0 {
			return
		}
		err := interpret(line)
		if err != nil {
			fmt.Printf("%v\n", err)
		}
	}
}

func runFile(path string) {
	code, err := ioutil.ReadFile(path) // the file is inside the local directory
	if err != nil {
		fmt.Printf("%v\n", err)
		os.Exit(65)
	}

	err = interpret(string(code))
	if err != nil {
		fmt.Printf("%v\n", err)
		os.Exit(65)
	}
}

func interpret(src string) error {
	tokens, err := varaq.Tokenize(src)
	if err != nil {
		return fmt.Errorf("%v", err)
	}

	code := varaq.Parse(tokens)
	err = varaq.Interpret(code, os.Args[1:], os.Stdout)
	if err != nil {
		fmt.Printf("%v\n", err)
		return err
	}

	return nil
}

func jsInterpret(this js.Value, args []js.Value) interface{} {
	if len(args) < 1 {
		return js.ValueOf("no input")
	}
	input := args[0].String()

	tokens, err := varaq.Tokenize(input)
	if err != nil {
		return js.ValueOf(fmt.Errorf("%v", err))
	}

	code := varaq.Parse(tokens)
	buf := bytes.NewBufferString("")

	strings := make([]string, len(args[1:]))
	for i, jsVal := range args[1:] {
		strings[i] = jsVal.String()
	}

	err = varaq.Interpret(code, strings, buf)
	if err != nil {
		return js.ValueOf(fmt.Errorf("%v", err))
	}

	return js.ValueOf(buf.String())
}