package cdr

import (
	"encoding/csv"
	"fmt"
	"os"
	"regexp"
)

type PriceType int

const (
	PriceUnknown PriceType = iota
	PriceCall
	PriceText
	PriceData
)

type Price struct {
	Type        PriceType
	BuyEach     int
	BuyUnit     int
	SellEach    int
	SellUnit    int
	Destination string
}

const FieldsPerPricingLine = 14

// PriceImportIndex keeps track of what column corresponds to what data
type PriceImportIndex int

const (
	PriceImportRegion PriceImportIndex = iota
	PriceImportDestination
	PriceImportPpcBuy
	PriceImportPpmBuyFixed
	PriceImportPpmBuyMobile
	PriceImportPpcSell
	PriceImportPpmSellFixed
	PriceImportPpmSellMobile
	PriceImportPpcMargin
	PriceImportPpmMarginFixed
	PriceImportPpmMarginMobile
	PriceImportPpcSellVAT
	PriceImportPpmSellFixedVAT
	PriceImportPpmSellMobileVAT
)

var (
	PricingRegexp = regexp.MustCompile(`(\d+\.\d+)`)
)

// ImportPricesFile expects a CSV with the following fields:
//   - Regio (string)
//   - Destination (string)
//   - ppc_buy
//   - ppm_buy_fixed
//   - ppm_buy_mobile
//   - ppc_sell
//   - ppm_sell_fixed
//   - ppm_sell_mobile
//   - ppc_margin
//   - ppm_margin_fixed
//   - ppm_margin_mobile
//   - ppc_sell_vat
//   - ppm_sell_fixed_vat
//   - ppm_sell_mobile_vat

func ImportPricesFile(fn string) ([]Price, error) {
	f, err := os.Open(fn)
	if err != nil {
		return nil, fmt.Errorf("opening file %q failed: %v", fn, err)
	}

	csvReader := csv.NewReader(f)
	csvReader.FieldsPerRecord = FieldsPerPricingLine
	csvReader.Comma = ';'

	all, err := csvReader.ReadAll()
	if err != nil {
		return nil, fmt.Errorf("reading csv %q failed: %v", fn, err)
	}

	var ret []Price
	priceTypes := []string{
		"Fixed",
		"Mobile",
	}
	for _, line := range all {
		if line[PriceImportRegion] == "Regio" || line[PriceImportDestination] == "" {
			// Header line or no destination
			continue
		}

		for _, priceType := range priceTypes {
			destination := line[PriceImportRegion] + " - " + line[PriceImportDestination] + " - " + priceType
			priceKind := PriceCall // TODO: import Text and Data through the same CSV

			var buyUnit, sellUnit int
			buyEach := convertImportedPrice(line[PriceImportPpcBuy])
			sellEach := convertImportedPrice(line[PriceImportPpcSell])
			switch priceType {
			case "Fixed":
				buyUnit = convertImportedPrice(line[PriceImportPpmBuyFixed])
				sellUnit = convertImportedPrice(line[PriceImportPpmSellFixed])
			case "Mobile":
				buyUnit = convertImportedPrice(line[PriceImportPpmBuyMobile])
				sellUnit = convertImportedPrice(line[PriceImportPpmSellMobile])
			default:
				return nil, fmt.Errorf("unsupported priceType %q", priceType)
			}

			// Extract the prices
			ret = append(ret, Price{
				Type:        priceKind,
				Destination: destination,
				BuyEach:     buyEach,
				BuyUnit:     buyUnit,
				SellEach:    sellEach,
				SellUnit:    sellUnit,
			})
		}
	}
	return ret, nil
}

func convertImportedPrice(s string) int {
	if s == "" {
		return 0
	}

	p := PricingRegexp.FindString(s)
	conv, err := decimalStrToInt(p, ".")
	if err != nil {
		panic("cannot convert ImportedPrice: " + err.Error())
	}
	return conv
}