//
// gopsutil is a port of psutil(http://pythonhosted.org/psutil/).
// This covers these architectures.
//  - linux (amd64, arm)
//  - freebsd (amd64)
//  - windows (amd64)
package gopsutil

import (
	"bufio"
	"errors"
	"os"
	"reflect"
	"strconv"
	"strings"
)

var NotImplementedError = errors.New("not implemented yet")

// readLines reads contents from file and splits them by new line.
// A convenience wrapper to readLinesOffsetN(filename, 0, -1).
func readLines(filename string) ([]string, error) {
	return readLinesOffsetN(filename, 0, -1)
}

// readLines reads contents from file and splits them by new line.
// The offset tells at which line number to start.
// The count determines the number of lines to read (starting from offset):
//   n >= 0: at most n lines
//   n < 0: whole file
func readLinesOffsetN(filename string, offset uint, n int) ([]string, error) {
	f, err := os.Open(filename)
	if err != nil {
		return []string{""}, err
	}
	defer f.Close()

	var ret []string

	r := bufio.NewReader(f)
	for i := 0; i < n+int(offset) || n < 0; i++ {
		line, err := r.ReadString('\n')
		if err != nil {
			break
		}
		if i < int(offset) {
			continue
		}
		ret = append(ret, strings.Trim(line, "\n"))
	}

	return ret, nil
}

func byteToString(orig []byte) string {
	n := -1
	l := -1
	for i, b := range orig {
		// skip left side null
		if l == -1 && b == 0 {
			continue
		}
		if l == -1 {
			l = i
		}

		if b == 0 {
			break
		}
		n = i + 1
	}
	if n == -1 {
		return string(orig)
	}
	return string(orig[l:n])
}

// Parse to int32 without error
func mustParseInt32(val string) int32 {
	vv, _ := strconv.ParseInt(val, 10, 32)
	return int32(vv)
}

// Parse to uint64 without error
func mustParseUint64(val string) uint64 {
	vv, _ := strconv.ParseInt(val, 10, 64)
	return uint64(vv)
}

// Parse to Float64 without error
func mustParseFloat64(val string) float64 {
	vv, _ := strconv.ParseFloat(val, 64)
	return vv
}

// Check the target string slice containes src or not
func stringContains(target []string, src string) bool {
	for _, t := range target {
		if t == src {
			return true
		}
	}
	return false
}

// get struct attributes.
// This method is used only for debugging platform dependent code.
func attributes(m interface{}) map[string]reflect.Type {
	typ := reflect.TypeOf(m)
	if typ.Kind() == reflect.Ptr {
		typ = typ.Elem()
	}

	attrs := make(map[string]reflect.Type)
	if typ.Kind() != reflect.Struct {
		return nil
	}

	for i := 0; i < typ.NumField(); i++ {
		p := typ.Field(i)
		if !p.Anonymous {
			attrs[p.Name] = p.Type
		}
	}

	return attrs
}

func pathExists(filename string) bool {
	if _, err := os.Stat(filename); err == nil {
		return true
	}
	return false
}