package main

import (
	"strconv"
	"unicode/utf8"
)

// Util.go is a collection of utility functions that are used throughout
// the program

// Count returns the length of a string in runes
// This is exactly equivalent to utf8.RuneCountInString(), just less characters
func Count(s string) int {
	return utf8.RuneCountInString(s)
}

// NumOccurences counts the number of occurences of a byte in a string
func NumOccurences(s string, c byte) int {
	var n int
	for i := 0; i < len(s); i++ {
		if s[i] == c {
			n++
		}
	}
	return n
}

// Spaces returns a string with n spaces
func Spaces(n int) string {
	var str string
	for i := 0; i < n; i++ {
		str += " "
	}
	return str
}

// Min takes the min of two ints
func Min(a, b int) int {
	if a > b {
		return b
	}
	return a
}

// Max takes the max of two ints
func Max(a, b int) int {
	if a > b {
		return a
	}
	return b
}

// IsWordChar returns whether or not the string is a 'word character'
// If it is a unicode character, then it does not match
// Word characters are defined as [A-Za-z0-9_]
func IsWordChar(str string) bool {
	if len(str) > 1 {
		// Unicode
		return false
	}
	c := str[0]
	return (c >= '0' && c <= '9') || (c >= 'A' && c <= 'Z') || (c >= 'a' && c <= 'z') || (c == '_')
}

// IsWhitespace returns true if the given rune is a space, tab, or newline
func IsWhitespace(c rune) bool {
	return c == ' ' || c == '\t' || c == '\n'
}

// Contains returns whether or not a string array contains a given string
func Contains(list []string, a string) bool {
	for _, b := range list {
		if b == a {
			return true
		}
	}
	return false
}

// Insert makes a simple insert into a string at the given position
func Insert(str string, pos int, value string) string {
	return string([]rune(str)[:pos]) + value + string([]rune(str)[pos:])
}

// GetLeadingWhitespace returns the leading whitespace of the given string
func GetLeadingWhitespace(str string) string {
	ws := ""
	for _, c := range str {
		if c == ' ' || c == '\t' {
			ws += string(c)
		} else {
			break
		}
	}
	return ws
}

// IsSpaces checks if a given string is only spaces
func IsSpaces(str string) bool {
	for _, c := range str {
		if c != ' ' {
			return false
		}
	}

	return true
}

// ParseBool is almost exactly like strconv.ParseBool, except it also accepts 'on' and 'off'
// as 'true' and 'false' respectively
func ParseBool(str string) (bool, error) {
	if str == "on" {
		return true, nil
	}
	if str == "off" {
		return false, nil
	}
	return strconv.ParseBool(str)
}