bogem/vnehm

// Copyright 2016 Albert Nigmatzianov. All rights reserved.
// Use of this source code is governed by a MIT-style
// license that can be found in the LICENSE file.

package ui

import (
    "bytes"
    "sort"
    "strconv"
    "strings"
)

var (
    output bytes.Buffer

    newlineItem = MenuItem{
        Desc: "",
    }
    quitItem = MenuItem{
        Index: "q",
        Desc:  RedString("Quit"),
        Run:   func() { Quit() },
    }
)

type Menu struct {
    items []MenuItem
}

func (m *Menu) AddItems(mis ...MenuItem) {
    m.items = append(m.items, mis...)
}

func (m *Menu) AddNewline() {
    m.AddItems(newlineItem)
}

func (m *Menu) Clear() {
    m.items = m.items[:0]
}

func (m Menu) Show() {
    var choices = make(map[string]func())

    m.AddItems(quitItem)

    output.Reset()

    for _, item := range m.items {
        output.WriteString(item.String() + "\n")
        if item.IsRunnable() {
            choices[item.Index] = item.Run
        }
    }
    Println(output.String())

    choose(choices)
}

func choose(choices map[string]func()) {
    Print("Enter option: ")
    var index = ReadInput()
    var chosen = choices[index]

    Newline()

    for {
        if chosen != nil {
            chosen()
            break
        } else {
            var keys []string
            for k := range choices {
                keys = append(keys, k)
            }
            keys = sortKeys(keys)

            Print("You must choose one of [" + strings.Join(keys, ", ") + "]: ")
            index = ReadInput()
            chosen = choices[index]
        }
    }
}

func sortKeys(keys []string) []string {
    // find numeric keys
    var numKeys []int
    var stringKeys []string
    for _, v := range keys {
        vNum, err := strconv.Atoi(v)
        if err != nil {
            stringKeys = append(stringKeys, v)
            continue
        }
        numKeys = append(numKeys, vNum)
    }

    // sort keys
    sort.IntSlice(numKeys).Sort()
    sort.StringSlice(stringKeys).Sort()

    // convert numeric keys to string
    sNumKeys := make([]string, 0, len(numKeys))
    for _, n := range numKeys {
        sNumKeys = append(sNumKeys, strconv.Itoa(n))
    }

    sorted := make([]string, 0, len(keys))
    sorted = append(sorted, sNumKeys...)
    sorted = append(sorted, stringKeys...)

    return sorted
}