To use run: > go run <script_name> <stock symbol> and it will display Price and Volume graph from the past year in your terminal

termui_finance.go

// +build ignore
// Author: Weiyi Zheng, 2015
/* learning termui and go language
To use run: > go run <script_name> <stock symbol>
and it will display Price and Volume info from last year in your terminal
things are lacking:
- two graphs can't be scaled to the same width
- no control over axis label
- be cautious running any termui stuff in chromebook's Secure Shell, it will freeze

Things I learned when coding this:
- With a typed language, it is easier to access elements inside a struct with accessor function, not Pluck (in Go's case, it's Reflect)
- Strict variable checking and module checking sometimes is a little annoying. By commenting out one line that consumes a variable, you will have to comment out the definition (if there is no other place that use this variable), and comments out the imports
- "go fmt" is nice to have, but don't run it too often as it slows you down
- I still don't know how to create an array using variable as size. From pointer perspective it makes sense. Just use append
- NewList is such a strange syntax. You have no way telling whether you are calling a plain function or creating a object by simply looking at the function name. 
- what happened on January 2nd, 2006 at 3pm? why formatting a time requires me to remember this specific date? I rather remember one more person's birthday.
- var variable Int doesn't seemed to be needed in most use case. := is better. Though it increases the amount of documentation look up
- if you return an err object, you are forcing the caller to write some err handling code. Doesn't this lead to error handling everywhere?

*/

package main

import ui "github.com/gizak/termui"
import "github.com/doneland/yquotes"

import "time"
import "reflect"
import "os"
import "fmt"

// from reflect package, two reasons not to use
// 1, unpresented key will croak
// 2. look up is slow comparing to use static name
// to check the interface, checkout documentation at
// https://github.com/doneland/yquotes/blob/master/yquotes.go
func Pluck(prices []yquotes.PriceH, key string) []float64 {
	ps := []float64{}
	for _, price := range prices {
		reflected := reflect.ValueOf(price)
		ps = append(ps, reflect.Indirect(reflected).FieldByName(key).Float())
	}
	return ps
}
func FsToInts(data []float64) []int {
	ps := []int{}
	for _, v := range data {
		ps = append(ps, int(v))
	}
	return ps
}

func main() {
	err := ui.Init()
	sticker := os.Args[1]

	if sticker == "" {
		fmt.Printf("Please add your sticker symbol as the first argument")
		os.Exit(1)
	}
	if err != nil {
		panic(err)
	}
	defer ui.Close()

	ui.UseTheme("helloworld")

	//from,_ := time.Parse("2006-01-02", "2015-01-01")
	//to   := time.Now()
	//prices, err := yquotes.GetDailyHistory("AAPL", from, to)
	prices, err := yquotes.HistoryForYears(sticker, 1, yquotes.Daily)
	if err != nil {
		panic(err)
	}
	// reverse, how to use a function?
	for i, j := 0, len(prices)-1; i < j; i, j = i+1, j-1 {
		prices[i], prices[j] = prices[j], prices[i]
	}

  stock, err := yquotes.NewStock(sticker, true)
  if err != nil {
    panic(err)
  }
	// title and stock symbol
	titlePar := ui.NewPar(fmt.Sprintf("Stock Price for %s - 1Y Daily (q to quit)", stock.Name))
	titlePar.Height = 1
	titlePar.Y = 1
	titlePar.HasBorder = false

	// price
	quoteC := ui.NewLineChart()
	quoteC.Border.Label = "Daily Adjusted Close"
	quoteC.Data = Pluck(prices, "AdjClose")
	quoteC.Height = 11
	quoteC.AxesColor = ui.ColorWhite
	quoteC.LineColor = ui.ColorYellow

    // Price information
  lastPrice     := stock.Price // Price struct 
  	strs := []string{
      fmt.Sprintf("Bid: %.2f", lastPrice.Bid),
      fmt.Sprintf("Ask: %.2f", lastPrice.Ask),
      fmt.Sprintf("Open: %.2f", lastPrice.Open),
      fmt.Sprintf("Last: %.2f", lastPrice.Last),
    }
  lastInfo := ui.NewList()

	lastInfo.Items = strs
	lastInfo.ItemFgColor = ui.ColorYellow
	lastInfo.Border.Label = "Info"
	lastInfo.Height = 11

	// volume
	/*
		  spark := ui.NewSparkline()
			spark.Height = 8
			//spdata := sinpsint
		  spark.Data = FsToInts(Pluck(prices, "Volume"))
			spark.TitleColor = ui.ColorWhite
		  spark.Title = "Volume"
		  sparklines := ui.NewSparklines(spark)
		  sparklines.Height = 8
		  sparklines.Border.Label = "Volume"
	*/

	volumeC := ui.NewLineChart()
	volumeC.Height = 6
	//volumeC.Mode = "dot"
	volumeC.Data = Pluck(prices, "Volume")
	volumeC.AxesColor = ui.ColorWhite
	volumeC.LineColor = ui.ColorWhite
	volumeC.Border.Label = "Volume"

	par := ui.NewPar("Author is too lazy to leave anything here")
	par.Height = 5
	par.Border.Label = "Preserved Space"

	// build layout
	ui.Body.AddRows(
		ui.NewRow(
			ui.NewCol(10, 2, titlePar),
    ),
		ui.NewRow(
			ui.NewCol(10, 0, quoteC),
			ui.NewCol(2, 0, lastInfo)),
		ui.NewRow(
			ui.NewCol(10, 0, volumeC),
			ui.NewCol(2, 0, par)),
	)

	// calculate layout
	ui.Body.Align()

	draw := func(t int) {
		//volumnSpark.Lines[0].Data = spdata[t:]
		//quoteC.Data = sinps[2*t:]
		ui.Render(ui.Body)
	}

	evt := ui.EventCh()

	i := 0
	for {
		select {
		case e := <-evt:
			if e.Type == ui.EventKey && e.Ch == 'q' {
				return
			}
		default:
			ui.Body.Width = ui.TermWidth()
			ui.Body.Align()

			draw(i)
			i++
			if i == 102 {
				return
			}
			time.Sleep(time.Second / 2)
		}
	}
}