package utils

import (
	"bytes"
	"encoding/json"
	"fmt"
	"html/template"
	"math"
	"reflect"
	"regexp"
	"strings"
	"time"

	"github.com/go-errors/errors"
	"github.com/jesseduffield/gocui"

	"github.com/fatih/color"
)

// SplitLines takes a multiline string and splits it on newlines
// currently we are also stripping \r's which may have adverse effects for
// windows users (but no issues have been raised yet)
func SplitLines(multilineString string) []string {
	multilineString = strings.Replace(multilineString, "\r", "", -1)
	if multilineString == "" || multilineString == "\n" {
		return make([]string, 0)
	}
	lines := strings.Split(multilineString, "\n")
	if lines[len(lines)-1] == "" {
		return lines[:len(lines)-1]
	}
	return lines
}

// WithPadding pads a string as much as you want
func WithPadding(str string, padding int) string {
	uncoloredStr := Decolorise(str)
	if padding < len(uncoloredStr) {
		return str
	}
	return str + strings.Repeat(" ", padding-len(uncoloredStr))
}

// ColoredString takes a string and a colour attribute and returns a colored
// string with that attribute
func ColoredString(str string, colorAttribute color.Attribute) string {
	colour := color.New(colorAttribute)
	return ColoredStringDirect(str, colour)
}

// ColoredStringDirect used for aggregating a few color attributes rather than
// just sending a single one
func ColoredStringDirect(str string, colour *color.Color) string {
	return colour.SprintFunc()(fmt.Sprint(str))
}

// TrimTrailingNewline - Trims the trailing newline
// TODO: replace with `chomp` after refactor
func TrimTrailingNewline(str string) string {
	if strings.HasSuffix(str, "\n") {
		return str[:len(str)-1]
	}
	return str
}

// NormalizeLinefeeds - Removes all Windows and Mac style line feeds
func NormalizeLinefeeds(str string) string {
	str = strings.Replace(str, "\r\n", "\n", -1)
	str = strings.Replace(str, "\r", "", -1)
	return str
}

// Loader dumps a string to be displayed as a loader
func Loader() string {
	characters := "|/-\\"
	now := time.Now()
	nanos := now.UnixNano()
	index := nanos / 50000000 % int64(len(characters))
	return characters[index : index+1]
}

// ResolvePlaceholderString populates a template with values
func ResolvePlaceholderString(str string, arguments map[string]string) string {
	for key, value := range arguments {
		str = strings.Replace(str, "{{"+key+"}}", value, -1)
	}
	return str
}

// Min returns the minimum of two integers
func Min(x, y int) int {
	if x < y {
		return x
	}
	return y
}

type Displayable interface {
	GetDisplayStrings(bool) []string
}

type RenderListConfig struct {
	IsFocused bool
	Header    []string
}

func IsFocused(isFocused bool) func(c *RenderListConfig) {
	return func(c *RenderListConfig) {
		c.IsFocused = isFocused
	}
}

func WithHeader(header []string) func(c *RenderListConfig) {
	return func(c *RenderListConfig) {
		c.Header = header
	}
}

// RenderList takes a slice of items, confirms they implement the Displayable
// interface, then generates a list of their displaystrings to write to a panel's
// buffer
func RenderList(slice interface{}, options ...func(*RenderListConfig)) (string, error) {
	config := &RenderListConfig{}
	for _, option := range options {
		option(config)
	}

	s := reflect.ValueOf(slice)
	if s.Kind() != reflect.Slice {
		return "", errors.New("RenderList given a non-slice type")
	}

	displayables := make([]Displayable, s.Len())

	for i := 0; i < s.Len(); i++ {
		value, ok := s.Index(i).Interface().(Displayable)
		if !ok {
			return "", errors.New("item does not implement the Displayable interface")
		}
		displayables[i] = value
	}

	return renderDisplayableList(displayables, *config)
}

// renderDisplayableList takes a list of displayable items, obtains their display
// strings via GetDisplayStrings() and then returns a single string containing
// each item's string representation on its own line, with appropriate horizontal
// padding between the item's own strings
func renderDisplayableList(items []Displayable, config RenderListConfig) (string, error) {
	if len(items) == 0 {
		return "", nil
	}

	stringArrays := getDisplayStringArrays(items, config.IsFocused)
	if len(config.Header) > 0 {
		stringArrays = append([][]string{config.Header}, stringArrays...)
	}

	if !displayArraysAligned(stringArrays) {
		return "", errors.New("Each item must return the same number of strings to display")
	}

	padWidths := getPadWidths(stringArrays)
	paddedDisplayStrings := getPaddedDisplayStrings(stringArrays, padWidths)

	return strings.Join(paddedDisplayStrings, "\n"), nil
}

// Decolorise strips a string of color
func Decolorise(str string) string {
	re := regexp.MustCompile(`\x1B\[([0-9]{1,2}(;[0-9]{1,2})?)?[m|K]`)
	return re.ReplaceAllString(str, "")
}

func getPadWidths(stringArrays [][]string) []int {
	if len(stringArrays[0]) <= 1 {
		return []int{}
	}
	padWidths := make([]int, len(stringArrays[0])-1)
	for i := range padWidths {
		for _, strings := range stringArrays {
			uncoloredString := Decolorise(strings[i])
			if len(uncoloredString) > padWidths[i] {
				padWidths[i] = len(uncoloredString)
			}
		}
	}
	return padWidths
}

func getPaddedDisplayStrings(stringArrays [][]string, padWidths []int) []string {
	paddedDisplayStrings := make([]string, len(stringArrays))
	for i, stringArray := range stringArrays {
		if len(stringArray) == 0 {
			continue
		}
		for j, padWidth := range padWidths {
			paddedDisplayStrings[i] += WithPadding(stringArray[j], padWidth) + " "
		}
		paddedDisplayStrings[i] += stringArray[len(padWidths)]
	}
	return paddedDisplayStrings
}

// displayArraysAligned returns true if every string array returned from our
// list of displayables has the same length
func displayArraysAligned(stringArrays [][]string) bool {
	for _, strings := range stringArrays {
		if len(strings) != len(stringArrays[0]) {
			return false
		}
	}
	return true
}

func getDisplayStringArrays(displayables []Displayable, isFocused bool) [][]string {
	stringArrays := make([][]string, len(displayables))
	for i, item := range displayables {
		stringArrays[i] = item.GetDisplayStrings(isFocused)
	}
	return stringArrays
}

// IncludesString if the list contains the string
func IncludesString(list []string, a string) bool {
	for _, b := range list {
		if b == a {
			return true
		}
	}
	return false
}

// NextIndex returns the index of the element that comes after the given number
func NextIndex(numbers []int, currentNumber int) int {
	for index, number := range numbers {
		if number > currentNumber {
			return index
		}
	}
	return 0
}

// PrevIndex returns the index that comes before the given number, cycling if we reach the end
func PrevIndex(numbers []int, currentNumber int) int {
	end := len(numbers) - 1
	for i := end; i >= 0; i -= 1 {
		if numbers[i] < currentNumber {
			return i
		}
	}
	return end
}

func AsJson(i interface{}) string {
	bytes, _ := json.MarshalIndent(i, "", "    ")
	return string(bytes)
}

func FormatBinaryBytes(b int) string {
	n := float64(b)
	units := []string{"B", "kiB", "MiB", "GiB", "TiB", "PiB", "EiB", "ZiB", "YiB"}
	for _, unit := range units {
		if n > math.Pow(2, 10) {
			n = n / math.Pow(2, 10)
		} else {
			val := fmt.Sprintf("%.2f%s", n, unit)
			if val == "0.00B" {
				return "0B"
			}
			return val
		}
	}
	return "a lot"
}

func FormatDecimalBytes(b int) string {
	n := float64(b)
	units := []string{"B", "kB", "MB", "GB", "TB", "PB", "EB", "ZB", "YB"}
	for _, unit := range units {
		if n > math.Pow(10, 3) {
			n = n / math.Pow(10, 3)
		} else {
			val := fmt.Sprintf("%.2f%s", n, unit)
			if val == "0.00B" {
				return "0B"
			}
			return val
		}
	}
	return "a lot"
}

func ApplyTemplate(str string, object interface{}) string {
	var buf bytes.Buffer
	template.Must(template.New("").Parse(str)).Execute(&buf, object)
	return buf.String()
}

// GetGocuiAttribute gets the gocui color attribute from the string
func GetGocuiAttribute(key string) gocui.Attribute {
	colorMap := map[string]gocui.Attribute{
		"default":   gocui.ColorDefault,
		"black":     gocui.ColorBlack,
		"red":       gocui.ColorRed,
		"green":     gocui.ColorGreen,
		"yellow":    gocui.ColorYellow,
		"blue":      gocui.ColorBlue,
		"magenta":   gocui.ColorMagenta,
		"cyan":      gocui.ColorCyan,
		"white":     gocui.ColorWhite,
		"bold":      gocui.AttrBold,
		"reverse":   gocui.AttrReverse,
		"underline": gocui.AttrUnderline,
	}
	value, present := colorMap[key]
	if present {
		return value
	}
	return gocui.ColorWhite
}

// GetColorAttribute gets the color attribute from the string
func GetColorAttribute(key string) color.Attribute {
	colorMap := map[string]color.Attribute{
		"default":   color.FgWhite,
		"black":     color.FgBlack,
		"red":       color.FgRed,
		"green":     color.FgGreen,
		"yellow":    color.FgYellow,
		"blue":      color.FgBlue,
		"magenta":   color.FgMagenta,
		"cyan":      color.FgCyan,
		"white":     color.FgWhite,
		"bold":      color.Bold,
		"underline": color.Underline,
	}
	value, present := colorMap[key]
	if present {
		return value
	}
	return color.FgWhite
}