package ledger

import (
	"fmt"
)

type Files []string

func NewFiles(p string, q ...string) (Files, error) {
	f := Files(append([]string{p}, q...))
	_, err := f.Deltas()
	return f, err
}

func Balances(deltas []Delta) (map[string]map[Currency]float64, error) {
	result := make(map[string]map[Currency]float64)
	for _, delta := range deltas {
		if _, ok := result[delta.Account]; !ok {
			result[delta.Account] = make(map[Currency]float64)
		}
		if _, ok := result[delta.Account][delta.Currency]; !ok {
			result[delta.Account][delta.Currency] = 0
		}
		result[delta.Account][delta.Currency] += delta.Value
	}

	return result, nil
}

func (files Files) Deltas(like ...Like) ([]Delta, error) {
	transactions, err := files.transactions()
	if err != nil {
		return nil, err
	}
	result := make([]Delta, 0, len(transactions)*2)
	for _, transaction := range transactions {
		sums := map[string]float64{}
		for _, acc := range transaction.recipients {
			sums[acc.currency] += acc.value
			delta := newDelta(
				transaction.date,
				transaction.description,
				acc.name,
				acc.value,
				acc.currency,
			)
			if likes(like).all(delta) {
				result = append(result, delta)
			}
		}
		for currency, value := range sums {
			if value == 0 {
				continue
			}
			if transaction.payee == "" {
				return nil, fmt.Errorf("didnt find net zero and no dumping ground payee set: %+v", transaction)
			}
			delta := newDelta(
				transaction.date,
				transaction.description,
				transaction.payee,
				-1.0*value,
				currency,
			)
			if likes(like).all(delta) {
				result = append(result, delta)
			}
		}
	}
	return result, nil
}