package main

import (
	"os"
)

func readFile(path string) (data []byte, err error) {
	f, err := os.Open(path)
	if err != nil { return }
	info, err := f.Stat()
	if err != nil {
		f.Close()
		return
	}
	sz := int32(info.Size())
	if sz == 0 { sz = 4096 }
	buf := []byte{:0:sz + 1}
	for {
		if len(buf) >= cap(buf) {
			nb := []byte{:len(buf):len(buf) * 2}
			copy(nb, buf)
			buf = nb
		}
		n, rerr := f.Read(buf[len(buf):cap(buf)])
		buf = buf[:len(buf)+n]
		if rerr != nil { break }
	}
	f.Close()
	data = buf
	return
}

func writeFile(path string, data []byte) (err error) {
	f, err := os.Create(path)
	if err != nil { return }
	_, err = f.Write(data)
	cerr := f.Close()
	if err == nil { err = cerr }
	return
}

func main() {
	args := os.Args
	if len(args) == 0 {
		args = argsFromCmdline()
	}
	if len(args) < 2 {
		os.Stderr().Write([]byte("usage: moxiefmt [-w] file.mx ...\n"))
		os.Exit(1)
	}

	write := false
	files := []string{:0:len(args)}
	for i := int32(1); i < int32(len(args)); i++ {
		a := args[i]
		if a == "-w" {
			write = true
		} else {
			files = append(files, a)
		}
	}

	if len(files) == 0 {
		os.Stderr().Write([]byte("no files specified\n"))
		os.Exit(1)
	}

	exitCode := int32(0)
	for i := int32(0); i < int32(len(files)); i++ {
		ok, err := processFile(files[i], write)
		if err != nil {
			os.Stderr().Write([]byte("moxiefmt: " | files[i] | ": " | err.Error() | "\n"))
			exitCode = 1
		}
		if !ok { exitCode = 1 }
	}
	os.Exit(exitCode)
}

func argsFromCmdline() []string {
	data, err := readFile("/proc/self/cmdline")
	if err != nil { return nil }
	args := []string{:0:8}
	start := int32(0)
	for i := int32(0); i < int32(len(data)); i++ {
		if data[i] == 0 {
			if i > start {
				args = append(args, string(data[start:i]))
			}
			start = i + 1
		}
	}
	if start < int32(len(data)) {
		args = append(args, string(data[start:]))
	}
	return args
}

func processFile(path string, write bool) (ok bool, err error) {
	src, err := readFile(path)
	if err != nil { return }

	out, errs := formatSource(string(src))
	reportErrors(path, errs)
	ok = len(errs) == 0

	if write {
		err = writeFile(path, []byte(out))
	} else {
		_, err = os.Stdout().Write([]byte(out))
	}
	return
}