package fs

import (
	"regexp"
	"strconv"
	"strings"

	"github.com/spf13/cast"
)

func (f Files) FilterByWildcard() Files {
	var result Files

	for i := len(f) - 1; i >= 0; i-- {
		result = append(result, f[i])
	}

	return result
}

func (f Files) FilterByRange1(from, to int) Files {
	var result Files
	size := len(f)

	if from > to {
		for i := from; i >= to; i-- {
			result = append(result, f[size-i])
		}
	} else {
		for i := from; i <= to; i++ {
			result = append(result, f[size-i])
		}
	}

	return result
}

func (f Files) FilterByRange2(from int) Files {
	var result Files
	size := len(f)

	for i := from; i >= 1; i-- {
		result = append(result, f[size-i])
	}

	return result
}

func (f Files) FilterByRange3(from int) Files {
	var result Files
	size := len(f)

	for i := from; i <= size; i++ {
		result = append(result, f[size-i])
	}

	return result
}

func (f Files) FilterByWords(words []string) Files {
	var result Files
	size := len(f)

	for _, word := range words {
		isInt, _ := regexp.MatchString("^[0-9]+$", word)

		if isInt {
			value, _ := strconv.Atoi(word)
			result = append(result, f[size-value])
		}
	}

	return result
}

func (f Files) Select(input string) Files {
	switch input {
	case "*":
	case "*+":
		return f.FilterByWildcard()
	case "*-":
		return f
	}

	range1Regex := "^([0-9]+)-([0-9]+)$"
	range2Regex := "^([0-9]+)-$"
	range3Regex := "^([0-9]+)\\+$"

	isRange1, _ := regexp.MatchString(range1Regex, input)
	isRange2, _ := regexp.MatchString(range2Regex, input)
	isRange3, _ := regexp.MatchString(range3Regex, input)

	if isRange1 {
		regex, _ := regexp.Compile(range1Regex)
		data := regex.FindStringSubmatch(input)

		return f.FilterByRange1(
			cast.ToInt(data[1]),
			cast.ToInt(data[2]),
		)
	}

	if isRange2 {
		regex, _ := regexp.Compile(range2Regex)
		data := regex.FindStringSubmatch(input)

		return f.FilterByRange2(cast.ToInt(data[1]))
	}

	if isRange3 {
		regex, _ := regexp.Compile(range3Regex)
		data := regex.FindStringSubmatch(input)

		return f.FilterByRange3(cast.ToInt(data[1]))
	}

	return f.FilterByWords(strings.Fields(input))
}