import type { Currency, EstimatedReward } from "../types";
import { formatAmount } from "../utils/format/formatAmount";
import { getCurrencyAmountKey } from "../utils/format/getCurrencyAmountKey";
import { getSupportedCurrency } from "../utils/format/getSupportedCurrency";
import { getRewardRank, getRewardValue, maxRewardPercent } from "./value";

/**
 * Format an {@link EstimatedReward} into a human-readable string.
 *
 * - `fixed`      → e.g. `"5 €"`
 * - `percentage` → e.g. `"10 %"`
 * - `tiered`     → the richest tier: max token amount (e.g. `"50 €"`) or, when
 *                  tiers only carry percentages, the max percent (e.g. `"10 %"`)
 *
 * Percentages are always rendered as a `"X %"` string: the backend never sends
 * a reference basket, so the reward cannot be resolved to a concrete amount
 * here. Callers that need a worked example use the `example` helpers instead.
 */
export function formatEstimatedReward(
    reward: EstimatedReward,
    currency?: Currency
): string {
    const supportedCurrency = getSupportedCurrency(currency);
    const key = getCurrencyAmountKey(supportedCurrency);

    switch (reward.payoutType) {
        case "fixed":
            return formatAmount(
                Math.round(reward.amount[key]),
                supportedCurrency
            );

        case "percentage":
            return `${reward.percent} %`;

        case "tiered": {
            const maxAmount = getRewardValue(reward, key);
            if (maxAmount > 0) {
                return formatAmount(Math.round(maxAmount), supportedCurrency);
            }
            const maxPercent = maxRewardPercent(reward);
            if (maxPercent > 0) {
                return `${maxPercent} %`;
            }
            return formatAmount(0, supportedCurrency);
        }
    }
}

/**
 * Format a reward for display, or return `undefined` when it is not worth
 * advertising. Callers rely on `undefined` to hide a badge / fall back to
 * other copy.
 *
 * A reward is hidden only when it carries no displayable value — a `fixed` or
 * `tiered` reward whose money value is `0` (e.g. an unknown token price). An
 * uncapped percentage always renders as `"X %"`, since the percent itself is
 * meaningful even without a money value.
 */
export function formatRewardOrHide(
    reward: EstimatedReward | undefined,
    currency?: Currency
): string | undefined {
    if (!reward) return undefined;
    const key = getCurrencyAmountKey(getSupportedCurrency(currency));
    if (getRewardRank(reward, key) <= 0) return undefined;
    return formatEstimatedReward(reward, currency);
}

/**
 * Replace the `{REWARD}` placeholder in a text string with a reward value.
 * If no reward is provided, returns the text with `{REWARD}` stripped.
 */
export function applyRewardPlaceholder(
    text: string,
    reward: string | undefined
): string {
    return reward
        ? text.replaceAll("{REWARD}", reward)
        : text.replaceAll("{REWARD}", "");
}