mop/layout.go

// Copyright (c) 2013 by Michael Dvorkin. All Rights Reserved.
// Use of this source code is governed by a MIT-style license that can
// be found in the LICENSE file.

package mop

import (
	`bytes`
	`fmt`
	`reflect`
	`regexp`
	`strings`
	`text/template`
	`time`
)

// Column describes formatting rules for individual column within the list
// of stock quotes.
type Column struct {
	width	   int 		       // Column width.
	name       string	       // The name of the field in the Stock struct.
	title	   string	       // Column title to display in the header.
	formatter  func(string)string  // Optional function to format the contents of the column.
}

// Layout is used to format and display all the collected data, i.e. market
// updates and the list of stock quotes.
type Layout struct {
	columns         []Column	    // List of stock quotes columns.
	sorter          *Sorter		    // Pointer to sorting receiver.
	regex           *regexp.Regexp	    // Pointer to regular expression to align decimal points.
	marketTemplate  *template.Template  // Pointer to template to format market data.
	quotesTemplate  *template.Template  // Pointer to template to format the list of stock quotes.
}

// Creates the layout and assigns the default values that stay unchanged.
func NewLayout() *Layout {
	layout := &Layout{}
	layout.columns = []Column{
		{ -7, `Ticker`,    `Ticker`,    nil      },
		{ 10, `LastTrade`, `Last`,      currency },
		{ 10, `Change`,    `Change`,    currency },
		{ 10, `ChangePct`, `Change%`,   last     },
		{ 10, `Open`,      `Open`,      currency },
		{ 10, `Low`,       `Low`,       currency },
		{ 10, `High`,      `High`,      currency },
		{ 10, `Low52`,     `52w Low`,   currency },
		{ 10, `High52`,    `52w High`,  currency },
		{ 11, `Volume`,    `Volume`,    nil      },
		{ 11, `AvgVolume`, `AvgVolume`, nil      },
		{  9, `PeRatio`,   `P/E`,       blank    },
		{  9, `Dividend`,  `Dividend`,  zero     },
		{  9, `Yield`,     `Yield`,     percent  },
		{ 11, `MarketCap`, `MktCap`,    currency },
	}
	layout.regex = regexp.MustCompile(`(\.\d+)[BMK]?$`)
	layout.marketTemplate = buildMarketTemplate()
	layout.quotesTemplate = buildQuotesTemplate()

	return layout
}

// Market merges given market data structure with the market template and
// returns formatted string that includes highlighting markup.
func (layout *Layout) Market(market *Market) string {
	if ok, err := market.Ok(); !ok {  // If there was an error fetching market data...
		return err		  // then simply return the error string.
	}

	highlight(market.Dow, market.Sp500, market.Nasdaq,
		market.Tokyo, market.HongKong, market.London, market.Frankfurt,
		market.Yield, market.Oil, market.Euro, market.Gold)
	buffer := new(bytes.Buffer)
	layout.marketTemplate.Execute(buffer, market)

	return buffer.String()
}

// Quotes uses quotes template to format timestamp, stock quotes header,
// and the list of given stock quotes. It returns formatted string with
// all the necessary markup.
func (layout *Layout) Quotes(quotes *Quotes) string {
	if ok, err := quotes.Ok(); !ok {  // If there was an error fetching stock quotes...
		return err		  // then simply return the error string.
	}

	vars := struct {
		Now    string	// Current timestamp.
		Header string	// Formatted header line.
		Stocks []Stock	// List of formatted stock quotes.
	}{
		time.Now().Format(`3:04:05pm PST`),
		layout.Header(quotes.profile),
		layout.prettify(quotes),
	}

	buffer := new(bytes.Buffer)
	layout.quotesTemplate.Execute(buffer, vars)

	return buffer.String()
}

// Header iterates over column titles and formats the header line. The
// formatting includes placing an arrow next to the sorted column title.
// When the column editor is active it knows how to highlight currently
// selected column title.
func (layout *Layout) Header(profile *Profile) string {
	str, selectedColumn := ``, profile.selectedColumn

	for i,col := range layout.columns {
		arrow := arrowFor(i, profile)
		if i != selectedColumn {
			str += fmt.Sprintf(`%*s`, col.width, arrow + col.title)
		} else {
			str += fmt.Sprintf(`<r>%*s</r>`, col.width, arrow + col.title)
		}
	}

	return `<u>` + str + `</u>`
}

// TotalColumns is the utility method for the column editor that returns
// total number of columns.
func (layout *Layout) TotalColumns() int {
	return len(layout.columns)
}

//-----------------------------------------------------------------------------
func (layout *Layout) prettify(quotes *Quotes) []Stock {
	pretty := make([]Stock, len(quotes.stocks))
	//
	// Iterate over the list of stocks and properly format all its columns.
	//
	for i, stock := range quotes.stocks {
		pretty[i].Advancing = stock.Advancing
		//
		// Iterate over the list of stock columns. For each column name:
		// - Get current column value.
		// - If the column has the formatter method then call it.
		// - Set the column value padding it to the given width.
		//
		for _,column := range layout.columns {
			// ex. value = stock.Change
			value := reflect.ValueOf(&stock).Elem().FieldByName(column.name).String()
			if column.formatter != nil {
				// ex. value = currency(value)
				value = column.formatter(value)
			}
			// ex. pretty[i].Change = layout.pad(value, 10)
			reflect.ValueOf(&pretty[i]).Elem().FieldByName(column.name).SetString(layout.pad(value, column.width))
		}
	}

	profile := quotes.profile
	if layout.sorter == nil { // Initialize sorter on first invocation.
		layout.sorter = NewSorter(profile)
	}
	layout.sorter.SortByCurrentColumn(pretty)
	//
	// Group stocks by advancing/declining unless sorted by Chanage or Change%
	// in which case the grouping has been done already.
	//
	if profile.Grouped && (profile.SortColumn < 2 || profile.SortColumn > 3) {
		pretty = group(pretty)
	}

	return pretty
}

//-----------------------------------------------------------------------------
func (layout *Layout) pad(str string, width int) string {
	match := layout.regex.FindStringSubmatch(str)
	if len(match) > 0 {
		switch len(match[1]) {
		case 2:
			str = strings.Replace(str, match[1], match[1] + `0`, 1)
		case 4, 5:
			str = strings.Replace(str, match[1], match[1][0:3], 1)
		}
	}

	return fmt.Sprintf(`%*s`, width, str)
}

//-----------------------------------------------------------------------------
func buildMarketTemplate() *template.Template {
	markup := `<yellow>Dow</> {{.Dow.change}} ({{.Dow.percent}}) at {{.Dow.latest}} <yellow>S&P 500</> {{.Sp500.change}} ({{.Sp500.percent}}) at {{.Sp500.latest}} <yellow>NASDAQ</> {{.Nasdaq.change}} ({{.Nasdaq.percent}}) at {{.Nasdaq.latest}}
<yellow>Tokyo</> {{.Tokyo.change}} ({{.Tokyo.percent}}) at {{.Tokyo.latest}} <yellow>HK</> {{.HongKong.change}} ({{.HongKong.percent}}) at {{.HongKong.latest}} <yellow>London</> {{.London.change}} ({{.London.percent}}) at {{.London.latest}} <yellow>Frankfurt</> {{.Frankfurt.change}} ({{.Frankfurt.percent}}) at {{.Frankfurt.latest}} {{if .IsClosed}}<right>U.S. markets closed</right>{{end}}
<yellow>10-Year Yield</> {{.Yield.latest}}% ({{.Yield.change}}) <yellow>Euro</> ${{.Euro.latest}} ({{.Euro.change}}%) <yellow>Yen</> ¥{{.Yen.latest}} ({{.Yen.change}}%) <yellow>Oil</> ${{.Oil.latest}} ({{.Oil.change}}%) <yellow>Gold</> ${{.Gold.latest}} ({{.Gold.change}}%)`

	return template.Must(template.New(`market`).Parse(markup))
}

//-----------------------------------------------------------------------------
func buildQuotesTemplate() *template.Template {
	markup := `<right><white>{{.Now}}</></right>



{{.Header}}
{{range.Stocks}}{{if .Advancing}}<green>{{end}}{{.Ticker}}{{.LastTrade}}{{.Change}}{{.ChangePct}}{{.Open}}{{.Low}}{{.High}}{{.Low52}}{{.High52}}{{.Volume}}{{.AvgVolume}}{{.PeRatio}}{{.Dividend}}{{.Yield}}{{.MarketCap}}</>
{{end}}`

	return template.Must(template.New(`quotes`).Parse(markup))
}

//-----------------------------------------------------------------------------
func highlight(collections ...map[string]string) {
	for _, collection := range collections {
		if collection[`change`][0:1] != `-` {
			collection[`change`] = `<green>` + collection[`change`] + `</>`
		}
	}
}

//-----------------------------------------------------------------------------
func group(stocks []Stock) []Stock {
	grouped := make([]Stock, len(stocks))
	current := 0

	for _,stock := range stocks {
		if stock.Advancing {
			grouped[current] = stock
			current++
		}
	}
	for _,stock := range stocks {
		if !stock.Advancing {
			grouped[current] = stock
			current++
		}
	}

	return grouped
}

//-----------------------------------------------------------------------------
func arrowFor(column int, profile *Profile) string {
	if column == profile.SortColumn {
		if profile.Ascending {
			return string('\U00002191')
		}
		return string('\U00002193')
	}
	return ``
}

//-----------------------------------------------------------------------------
func blank(str string) string {
	if len(str) == 3 && str[0:3] == `N/A` {
		return `-`
	}

	return str
}

//-----------------------------------------------------------------------------
func zero(str string) string {
	if str == `0.00` {
		return `-`
	}

	return currency(str)
}

//-----------------------------------------------------------------------------
func last(str string) string {
	if len(str) >= 6 && str[0:6] == `N/A - ` {
		return str[6:]
	}

	return percent(str)
}

//-----------------------------------------------------------------------------
func currency(str string) string {
	if str == `N/A` {
		return `-`
	}
	if sign := str[0:1]; sign == `+` || sign == `-` {
		return sign + `$` + str[1:]
	}

	return `$` + str
}

// Returns percent value truncated at 2 decimal points.
//-----------------------------------------------------------------------------
func percent(str string) string {
	if str == `N/A` {
		return `-`
	}

	split := strings.Split(str, ".")
	if len(split) == 2 {
		digits := len(split[1])
		if digits > 2 {
			digits = 2
		}
		str = split[0] + "." + split[1][0:digits]
	}
	if str[len(str)-1] != '%' {
		str += `%`
	}
	return str
}