package ledger

import (
	"bufio"
	"bytes"
	"fmt"
	"io"
	"os"
	"strconv"
)

type BPIs string

type BPI map[string]float64

func NewBPIs(p string) (BPIs, error) {
	bpis := BPIs(p)
	_, err := bpis.values()
	return bpis, err
}

func (bpis BPIs) values() (map[Currency]BPI, error) {
	f, err := os.Open(string(bpis))
	if os.IsNotExist(err) {
		return nil, nil
	}
	if err != nil {
		return nil, err
	}
	defer f.Close()

	result := make(map[Currency]BPI)

	r := bufio.NewReader(f)
	for {
		line, err := readTransactionLine(r)
		if len(line) > 0 {
			fields := bytes.Fields(line)
			if len(fields) > 3 {
				date := fields[1]
				currency := fields[len(fields)-2]
				value, err := strconv.ParseFloat(string(fields[len(fields)-1][1:]), 64)
				if err != nil {
					return nil, err
				}
				return nil, fmt.Errorf("what do with %s/%s/%.2f?", date, currency, value)
			}
			return nil, fmt.Errorf("what do: %s", line)
		}
		if err == io.EOF {
			return result, nil
		} else if err != nil {
			return result, err
		}
	}
}