mop/sorter.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 (
	`sort`
	`strconv`
	`strings`
)

// Sorter gets called to sort stock quotes by one of the columns. The
// setup is rather lengthy; there should probably be more concise way
// that uses reflection and avoids hardcoding the column names.
type Sorter struct {
	profile  *Profile  // Pointer to where we store sort column and order.
}

type sortable []Stock
func (list sortable) Len() int { return len(list) }
func (list sortable) Swap(i, j int) { list[i], list[j] = list[j], list[i] }

type byTickerAsc       struct { sortable }
type byLastTradeAsc    struct { sortable }
type byChangeAsc       struct { sortable }
type byChangePctAsc    struct { sortable }
type byOpenAsc         struct { sortable }
type byLowAsc          struct { sortable }
type byHighAsc         struct { sortable }
type byLow52Asc        struct { sortable }
type byHigh52Asc       struct { sortable }
type byVolumeAsc       struct { sortable }
type byAvgVolumeAsc    struct { sortable }
type byPeRatioAsc      struct { sortable }
type byDividendAsc     struct { sortable }
type byYieldAsc        struct { sortable }
type byMarketCapAsc    struct { sortable }
                       
type byTickerDesc      struct { sortable }
type byLastTradeDesc   struct { sortable }
type byChangeDesc      struct { sortable }
type byChangePctDesc   struct { sortable }
type byOpenDesc        struct { sortable }
type byLowDesc         struct { sortable }
type byHighDesc        struct { sortable }
type byLow52Desc       struct { sortable }
type byHigh52Desc      struct { sortable }
type byVolumeDesc      struct { sortable }
type byAvgVolumeDesc   struct { sortable }
type byPeRatioDesc     struct { sortable }
type byDividendDesc    struct { sortable }
type byYieldDesc       struct { sortable }
type byMarketCapDesc   struct { sortable }

func (list byTickerAsc)       Less(i, j int) bool { return list.sortable[i].Ticker        < list.sortable[j].Ticker }
func (list byLastTradeAsc)    Less(i, j int) bool { return list.sortable[i].LastTrade     < list.sortable[j].LastTrade }
func (list byChangeAsc)       Less(i, j int) bool { return c(list.sortable[i].Change)     < c(list.sortable[j].Change) }
func (list byChangePctAsc)    Less(i, j int) bool { return c(list.sortable[i].ChangePct)  < c(list.sortable[j].ChangePct) }
func (list byOpenAsc)         Less(i, j int) bool { return list.sortable[i].Open          < list.sortable[j].Open }
func (list byLowAsc)          Less(i, j int) bool { return list.sortable[i].Low           < list.sortable[j].Low }
func (list byHighAsc)         Less(i, j int) bool { return list.sortable[i].High          < list.sortable[j].High }
func (list byLow52Asc)        Less(i, j int) bool { return list.sortable[i].Low52         < list.sortable[j].Low52 }
func (list byHigh52Asc)       Less(i, j int) bool { return list.sortable[i].High52        < list.sortable[j].High52 }
func (list byVolumeAsc)       Less(i, j int) bool { return list.sortable[i].Volume        < list.sortable[j].Volume }
func (list byAvgVolumeAsc)    Less(i, j int) bool { return list.sortable[i].AvgVolume     < list.sortable[j].AvgVolume }
func (list byPeRatioAsc)      Less(i, j int) bool { return list.sortable[i].PeRatio       < list.sortable[j].PeRatio }
func (list byDividendAsc)     Less(i, j int) bool { return list.sortable[i].Dividend      < list.sortable[j].Dividend }
func (list byYieldAsc)        Less(i, j int) bool { return list.sortable[i].Yield         < list.sortable[j].Yield }
func (list byMarketCapAsc)    Less(i, j int) bool { return m(list.sortable[i].MarketCap)  < m(list.sortable[j].MarketCap) }
                                  
func (list byTickerDesc)      Less(i, j int) bool { return list.sortable[j].Ticker        < list.sortable[i].Ticker }
func (list byLastTradeDesc)   Less(i, j int) bool { return list.sortable[j].LastTrade     < list.sortable[i].LastTrade }
func (list byChangeDesc)      Less(i, j int) bool { return c(list.sortable[j].ChangePct)  < c(list.sortable[i].ChangePct) }
func (list byChangePctDesc)   Less(i, j int) bool { return c(list.sortable[j].ChangePct)  < c(list.sortable[i].ChangePct) }
func (list byOpenDesc)        Less(i, j int) bool { return list.sortable[j].Open          < list.sortable[i].Open }
func (list byLowDesc)         Less(i, j int) bool { return list.sortable[j].Low           < list.sortable[i].Low }
func (list byHighDesc)        Less(i, j int) bool { return list.sortable[j].High          < list.sortable[i].High }
func (list byLow52Desc)       Less(i, j int) bool { return list.sortable[j].Low52         < list.sortable[i].Low52 }
func (list byHigh52Desc)      Less(i, j int) bool { return list.sortable[j].High52        < list.sortable[i].High52 }
func (list byVolumeDesc)      Less(i, j int) bool { return list.sortable[j].Volume        < list.sortable[i].Volume }
func (list byAvgVolumeDesc)   Less(i, j int) bool { return list.sortable[j].AvgVolume     < list.sortable[i].AvgVolume }
func (list byPeRatioDesc)     Less(i, j int) bool { return list.sortable[j].PeRatio       < list.sortable[i].PeRatio }
func (list byDividendDesc)    Less(i, j int) bool { return list.sortable[j].Dividend      < list.sortable[i].Dividend }
func (list byYieldDesc)       Less(i, j int) bool { return list.sortable[j].Yield         < list.sortable[i].Yield }
func (list byMarketCapDesc)   Less(i, j int) bool { return m(list.sortable[j].MarketCap)  < m(list.sortable[i].MarketCap) }

// Initialize simply saves the pointer to Profile for later use.
func (sorter *Sorter) Initialize(profile *Profile) *Sorter {
	sorter.profile = profile

	return sorter
}

// SortByCurrentColumn builds a list of sort interface based on current sort
// order, then calls sort.Sort to do the actual job.
func (sorter *Sorter) SortByCurrentColumn(stocks []Stock) *Sorter {
	var interfaces []sort.Interface

	if sorter.profile.Ascending {
		interfaces = []sort.Interface{
			byTickerAsc       { stocks },
			byLastTradeAsc    { stocks },
			byChangeAsc       { stocks },
			byChangePctAsc    { stocks },
			byOpenAsc         { stocks },
			byLowAsc          { stocks },
			byHighAsc         { stocks },
			byLow52Asc        { stocks },
			byHigh52Asc       { stocks },
			byVolumeAsc       { stocks },
			byAvgVolumeAsc    { stocks },
			byPeRatioAsc      { stocks },
			byDividendAsc     { stocks },
			byYieldAsc        { stocks },
			byMarketCapAsc    { stocks },
		}
	} else {
		interfaces = []sort.Interface{
			byTickerDesc      { stocks },
			byLastTradeDesc   { stocks },
			byChangeDesc      { stocks },
			byChangePctDesc   { stocks },
			byOpenDesc        { stocks },
			byLowDesc         { stocks },
			byHighDesc        { stocks },
			byLow52Desc       { stocks },
			byHigh52Desc      { stocks },
			byVolumeDesc      { stocks },
			byAvgVolumeDesc   { stocks },
			byPeRatioDesc     { stocks },
			byDividendDesc    { stocks },
			byYieldDesc       { stocks },
			byMarketCapDesc   { stocks },
		}
	}

	sort.Sort(interfaces[sorter.profile.SortColumn])

	return sorter
}

// The same exact method is used to sort by $Change and Change%. In both cases
// we sort by the value of Change% so that multiple $0.00s get sorted proferly.
func c(str string) float32 {
	trimmed := strings.Replace(strings.Trim(str, ` %`), `$`, ``, 1)
	value, _ := strconv.ParseFloat(trimmed, 32)
	return float32(value)
}

// When sorting by the market value we must first convert 42B etc. notations
// to proper numeric values.
func m(str string) float32 {
	multiplier := 1.0

	switch str[len(str)-1:len(str)] {	// Check the last character.
	case `B`:
		multiplier = 1000000000.0
	case `M`:
		multiplier = 1000000.0
	case `K`:
		multiplier = 1000.0
	}

	trimmed := strings.Trim(str, ` $BMK`)	// Get rid of non-numeric characters.
	value, _ := strconv.ParseFloat(trimmed, 32)

	return float32(value * multiplier)
}