package main

import (
	"fmt"
	"strconv"
	"os"
	"time"
	// "path/filepath"
	xl "anyxcelize"
	// "git.gabbott.dev/george/excelize/v2"
	st "saggytrousers"
	bt "badtudexo"
)

func usage() {
	fmt.Println(`bt-eqpct: check fields calculated from percentages
Usage:
	bt-eqpct FILE -b BASE -p PERCENT -r RESULT -t TOLERANCE
		      -s SHEET -o OUTPUT
As an example, -b can be a price, -p can be discount %, and -r discount value.
Then it is calculated: BASE * (PERCENT ± TOLERANCE), and checked if RESULT is
in this range. This checks the discount amount is always within the tolerance
of what the percentage should be; if out, either the percentage or the value
(either -p or -r) are probably wrong and need correcting in the data. 

The fields -b, -p and -r are required. If they are not passed, they will be 
prompted for. The function Locate() is used to find these and is passed the 
strings you passed in as params. 
`)
	os.Exit(0)
}

func parseArgs(args []string) {
	if len(args) < 2 {
		usage()
	}

	for i := 0; i < len(args); i++ {
		arg := args[i]
		switch arg {
		case "--help", "-h", "help", "helpme":
			usage()

		case "-b", "--base":
			i++
			base = args[i]
		case "-p", "--pct", "--percent", "--percentage":
			i++
			percent = args[i]
		case "-r", "--result":
			i++
			result = args[i]
		case "-t", "--tol", "--tolerance":
			i++
			t, err := strconv.ParseFloat(args[i], 64)
			if err != nil {
				fmt.Printf("Tolerance passed with -t could not be parsed into a float64\n")
				os.Exit(-1)
			}
			tol = t

		case "-s", "--sheet":
			i++
			sheet = args[i]

		case "--time", "--timings":
			timeme = true
		case "-o", "--out", "--output":
			i++
			out = args[i]
		case "-v", "--verbose":
			verbose = true

		default:
			filename = arg
		}
	}
}

// Constants
const ToleranceNotSetValue float64 = 420.69

// Globals
var base string
var percent string
var result string 
var tol float64 = ToleranceNotSetValue
var timeme bool = false
var verbose bool = false
var out string
var sheet string
var filename string


func main() {
	args := os.Args
	parseArgs(args)

	file, err := xl.OpenFile(filename)
	if err != nil {
		fmt.Printf("Cannot open file [%s], err [%v].\n", filename, err)
		return
	}

	/* Ask user to select the sheet */
	sheet = st.SelectSheet(file, sheet)

	/* Try find base, percent, result rows, else prompt for them */
	header     := st.GetHeader(file, sheet)
	baseIdx    := bt.LocateOrAsk(header, base, "Please choose the base: ")
	percentIdx := bt.LocateOrAsk(header, percent, "Please choose the percent: ")
	resultIdx  := bt.LocateOrAsk(header, result, "Please choose the resultant value: ")
	if tol == ToleranceNotSetValue {
		tol = st.GetFloat64("Please set the tolerance: ")
	}

	if verbose {
		fmt.Printf("base    index: %v\n", baseIdx)
		fmt.Printf("percent index: %v\n", percentIdx)
		fmt.Printf("result  index: %v\n", resultIdx)
	}
	
	/* Now load all rows in. */
	st.Log(verbose, "Loading rows...")
	loadStart := time.Now()
	rows := st.GetRows(file, sheet) // panics if fails, which is ok
	loadTime := time.Since(loadStart)
	st.Log(verbose, " done!\n")

	/* Get columns from rows as []float64 for call to EqPct. */
	var wasError bool = false
	start := time.Now()
	db, err := st.DowncastF64(st.TransmogrifyRows(rows, baseIdx)) 
	if err != nil {
		wasError = true
		fmt.Printf("%v\n", err)
	}
	dp, err := st.DowncastF64(st.TransmogrifyRows(rows, percentIdx)) 
	if err != nil {
		wasError = true
		fmt.Printf("%v\n", err)
	}
	dr, err := st.DowncastF64(st.TransmogrifyRows(rows, resultIdx)) 
	if err != nil {
		wasError = true
		fmt.Printf("%v\n", err)
	}
	st.Log(verbose, "About to call bt.EqPct.\n")

	if len(db) != len(dp) || len(dp) != len(dr) {
		st.ErrLog(verbose, 
			fmt.Sprintf("Length mismatch: db = %v, dp = %v, dr = %v",
			len(db), len(dp), len(dr)))
	} else {
		st.Log(verbose, fmt.Sprintf("Lengths are %v\n", len(db)))
	}

	indexes, err := bt.EqPct(db, dp, dr, tol)
	if err != nil {
		wasError = true
		fmt.Printf("There was an error [%v]\n", err)
		os.Exit(-1)
	}
	st.Log(verbose, "bt.EqPct completed successfully.\n")
	end := time.Since(start)
	// lenMax := len(string(len(db)))
	for _, v := range indexes {
		st.Log(true, fmt.Sprintf("%7v: %v * %v pct should be %v but found %v.\n", 
			v, 
			db[v], 
			dp[v], 
			(db[v] * dp[v])/100.00,
			dr[v]))
	}
	if verbose {
		fmt.Printf("base    index: %v\n", baseIdx)
		fmt.Printf("percent index: %v\n", percentIdx)
		fmt.Printf("result  index: %v\n", resultIdx)
	}

	if timeme {
		fmt.Printf("Time to load:    %v\n", loadTime)
		fmt.Printf("Time to process: %v\n", end)
	}
	if verbose {
		fmt.Printf("Was error: %v\n", wasError)
	}
}