package com.librewiki.coalgov.util;

import java.math.BigDecimal;
import java.math.RoundingMode;

public final class CoalMoney {
    public static final long CENTS_PER_COAL = 100L;

    private CoalMoney() {
    }

    public static long fromCoal(double coal) {
        return Math.round(coal * CENTS_PER_COAL);
    }

    public static long fromCoalConfig(double coal) {
        return Math.max(0L, fromCoal(coal));
    }

    public static String format(long cents) {
        boolean negative = cents < 0L;
        long absolute = Math.abs(cents);
        long coal = absolute / CENTS_PER_COAL;
        long coalCents = absolute % CENTS_PER_COAL;
        String prefix = negative ? "-" : "";
        if (coal > 0L && coalCents > 0L) {
            return prefix + coal + " coal " + coalCents + "cc";
        }
        if (coal > 0L) {
            return prefix + coal + " coal";
        }
        return prefix + coalCents + "cc";
    }

    public static long parsePositive(String raw) {
        long amount = parse(raw);
        return amount > 0L ? amount : -1L;
    }

    public static long parse(String raw) {
        if (raw == null) {
            return -1L;
        }
        String normalized = raw.trim().toLowerCase();
        if (normalized.isEmpty() || normalized.startsWith("-")) {
            return -1L;
        }
        try {
            if (normalized.endsWith("cc")) {
                return Long.parseLong(normalized.substring(0, normalized.length() - 2));
            }
            if (normalized.endsWith("c")) {
                return parseDecimalCoal(normalized.substring(0, normalized.length() - 1));
            }
            if (normalized.endsWith("coal")) {
                return parseDecimalCoal(normalized.substring(0, normalized.length() - 4));
            }
            return parseDecimalCoal(normalized);
        } catch (ArithmeticException | NumberFormatException exception) {
            return -1L;
        }
    }

    private static long parseDecimalCoal(String raw) {
        BigDecimal coal = new BigDecimal(raw.trim());
        BigDecimal cents = coal.multiply(BigDecimal.valueOf(CENTS_PER_COAL));
        return cents.setScale(0, RoundingMode.HALF_UP).longValueExact();
    }
}