package goutil

import (
	"bufio"
	"errors"
	"fmt"
	"io/ioutil"
	"os"
	"path"
	"path/filepath"
	"strings"
)

func DecorateError(s string, err error) error {
	if err != nil {
		return errors.New(s + ": " + err.Error())
	} else {
		return nil
	}
}

func WriteFile(filename string, data string) error {
	return ioutil.WriteFile(filename, []byte(data), 0644)
}

func ReadFile(filename string) (string, error) {
	data, err := ioutil.ReadFile(filename)
	return string(data), err
}

func TrimExt(path string) string {
	extension := filepath.Ext(path)
	return path[0 : len(path)-len(extension)]
}

func ListFilesExt(dir string, ext string) []string {
	list := make([]string, 0)
	ext = strings.ToUpper(ext)
	files, err := ioutil.ReadDir(dir)
	if err == nil {
		for _, file := range files {
			if !file.IsDir() {
				if strings.ToUpper(filepath.Ext(file.Name())) == ext {
					list = append(list, path.Join(dir, file.Name()))
				}
			}
		}
	}
	return list
}

func PathExists(path string) bool {
	if _, err := os.Stat(path); os.IsNotExist(err) {
		return false
	} else {
		return true
	}
}

func AskFor(question string) (string, error) {
	fmt.Print(question + ": ")
	reader := bufio.NewReader(os.Stdin)
	s, err := reader.ReadString('\n')
	if err == nil {
		return strings.TrimSpace(s), nil
	} else {
		return "", err
	}
}

func IntMin(x, y int) int {
	if x < y {
		return x
	} else {
		return y
	}
}

func IntMax(x, y int) int {
	if x > y {
		return x
	} else {
		return y
	}
}

func StrSliceAt(sl []string, i int) string {
	if i < len(sl) {
		return sl[i]
	} else {
		return ""
	}
}

func StrSlice(sl []string, start int, end int) []string {
	bound := func(i int) int { return IntMin(IntMax(0, i), len(sl)) }
	start = bound(start)
	end = bound(end)
	return sl[start:end]
}