package main

import (
	"flag"
	"fmt"
	"io"
	"my/go-translator/pkg/service"
	"my/go-translator/pkg/service_python"
	"os"
)

const (
	CPP_MODE = iota
	PYTHON_MODE
)

func main() {
	mode, target, header_file, addArduinoH, sources := getFlags()
	checkFlagsAreValid(sources)
	safeTranspile(mode, sources, target, header_file, addArduinoH)
}

func getFlags() (int, string, string, bool, []string) {
	pmode := flag.Bool("p", false, "Mode: C++ or Python")
	target := flag.String("o", "", "Write to file instead of stdout")
	header_file := flag.String("h", "", "Write headers to file also")
	addArduinoH := flag.Bool("a", false, "Add Arduino.h")
	flag.Parse()

	sources := flag.Args()

	mode := CPP_MODE
	if *pmode {
		mode = PYTHON_MODE
	}

	return mode, *target, *header_file, *addArduinoH, sources
}

func checkFlagsAreValid(sources []string) {
	if len(sources) == 0 {
		printUsage()
		os.Exit(1)
	}
}

func printUsage() {
	fmt.Print("This program transpiles Golang source into corresponding C++/python code.\n\n")
	fmt.Printf("Options:\n")
	flag.PrintDefaults()
	fmt.Print("\n")
	fmt.Print("Example:\n")
	fmt.Printf("\tgo-tr [-a] [-h header.h] [-o output.cpp] [-p] <input.go|input2.go|...>\n\n")
}

func safeTranspile(mode int, sources []string, target, header_file string, addArduinoH bool) {
	files := []io.Reader{}
	var err error

	for _, src := range sources {
		in, err := os.Open(src)
		if err != nil {
			fmt.Fprintf(os.Stderr, "Go source file [%s] could not be opened! %v", src, err)
			os.Exit(1)
		}
		defer in.Close()
		files = append(files, in)
	}

	out := os.Stdout
	if target != "" {
		os.Remove(target)
		out, err = os.OpenFile(target, os.O_CREATE|os.O_RDWR|os.O_SYNC, 0644)
		if err != nil {
			fmt.Fprintf(os.Stderr, "Arduino sketch file [%s] could not be opened! %v", target, err)
			os.Exit(1)
		}
	}

	var header_f *os.File
	if header_file != "" {
		os.Remove(header_file)
		header_f, err = os.OpenFile(header_file, os.O_CREATE|os.O_RDWR|os.O_SYNC, 0644)
		if err != nil {
			fmt.Fprintf(os.Stderr, "Header file [%s] could not be opened! %v", header_file, err)
			os.Exit(1)
		}
	}
	switch mode {
	case CPP_MODE:
		service := service.NewService(files, out)
		service.SetHeaderWriter(header_f)
		service.AddIncludeArduinoH(addArduinoH)
		if err := service.Start(); err != nil {
			fmt.Fprintf(os.Stderr, "%v", err)
			os.Exit(1)
		}
	case PYTHON_MODE:
		service := service_python.NewService(files[0], out)
		if err := service.Start(); err != nil {
			fmt.Fprintf(os.Stderr, "%v", err)
			os.Exit(1)
		}
	}
}