package cmds

import (
	"errors"
	"os"
	"os/user"
	"strconv"
	"strings"
	"syscall"
)

func Test(args []string) (int, error) {
	if len(args) <= 2 {
		return 1, errors.New("test requires at least two arguments")
	}

	if strings.HasPrefix(args[1], "-") {
		return genTest(args[1:]), nil
	} else {
		if len(args) != 4 {
			return 1, nil
		}
		_, err := strconv.Atoi(args[1])
		if err != nil {
			return testString(args[1:]), nil
		} else {
			return testNumber(args[1:]), nil
		}
	}
}

func testString(args []string) int {
	sTests := map[string]func() bool{
		"=":  func() bool { return args[0] == args[2] },
		"!=": func() bool { return args[0] != args[2] },
		"<":  func() bool { return strings.Compare(args[0], args[2]) < 0 },
		">":  func() bool { return strings.Compare(args[0], args[2]) > 0 },
	}
	if sTest, ok := sTests[args[1]]; ok && sTest() {
		return 0
	}
	return 1
}

func testNumber(args []string) int {
	a, _ := strconv.Atoi(args[0])
	b, err := strconv.Atoi(args[2])
	if err != nil {
		return 1
	}
	nTests := map[string]func() bool{
		"-eq": func() bool { return a == b },
		"-ne": func() bool { return a != b },
		"-gt": func() bool { return a > b },
		"-ge": func() bool { return a >= b },
		"-lt": func() bool { return a < b },
		"-le": func() bool { return a <= b },
	}
	if nTest, ok := nTests[args[1]]; ok && nTest() {
		return 0
	}
	return 1
}

func genTest(args []string) int {
	sTests := map[string]func() bool{
		"-n": func() bool { return len(args[1]) > 0 },
		"-z": func() bool { return len(args[1]) == 0 },
	}
	if sTest, ok := sTests[args[0]]; ok && sTest() {
		return 0
	}

	fi, err := os.Lstat(args[1])
	c, _ := user.Current()
	if err != nil {
		return 1
	}
	s := fi.Sys().(*syscall.Stat_t)
	uid, _ := strconv.Atoi(c.Uid)
	gid, _ := strconv.Atoi(c.Gid)

	fTests := map[string]func() bool{
		"-e": func() bool { return true },
		"-f": func() bool { return !fi.IsDir() },
		"-d": func() bool { return fi.IsDir() },
		"-r": func() bool { return fi.Mode().Perm()&0400 != 0 },
		"-w": func() bool { return fi.Mode().Perm()&0200 != 0 },
		"-x": func() bool { return fi.Mode().Perm()&0100 != 0 },
		"-S": func() bool { return fi.Size() > 0 },
		"-L": func() bool { return fi.Mode()&os.ModeSymlink != 0 },
		"-O": func() bool { return uid == int(s.Uid) },
		"-G": func() bool { return gid == int(s.Gid) },
	}

	if fTest, ok := fTests[args[0]]; ok && fTest() {
		return 0
	}
	return 1
}