export type ChartRow<T> = { item: T; value: number; even: boolean };

/** 图表取值：0 不画；碳减排可为负，展示时取绝对值。 */
export function chartValue(raw: number, carbon = false) {
	const n = Number(raw);
	if (!Number.isFinite(n) || n === 0) return 0;
	return carbon ? Math.abs(n) : n;
}

/**
 * 分类图数据：
 * - 部分有值：只保留当前指标 > 0 的类
 * - 全部为 0：evenSplit 时均分扇区（value=1 仅用于几何，even 标记给 tooltip 显示 0）
 */
export function chartSeries<T>(
	items: T[] | undefined,
	pick: (item: T) => number,
	opts?: { carbon?: boolean; evenSplit?: boolean }
): ChartRow<T>[] {
	const list = items || [];
	const rows = list.map(item => ({
		item,
		raw: chartValue(pick(item), opts?.carbon)
	}));
	const positive = rows.filter(e => e.raw > 0);
	if (positive.length) {
		return positive.map(e => ({ item: e.item, value: e.raw, even: false }));
	}
	if (opts?.evenSplit === false) {
		return rows.map(e => ({ item: e.item, value: 0, even: false }));
	}
	return rows.map(e => ({ item: e.item, value: 1, even: true }));
}

export function pieTooltipFormatter(unit = '') {
	return (p: any) => {
		const val = p.data?.even ? 0 : p.value;
		const u = unit ? ` ${unit}` : '';
		const pct = p.percent != null ? ` (${p.percent}%)` : '';
		return `${p.name}<br/>${val}${u}${pct}`;
	};
}

export function toPieData<T>(
	rows: ChartRow<T>[],
	name: (item: T) => string,
	color: (item: T) => string | undefined
) {
	return rows.map(row => ({
		name: name(row.item),
		value: row.value,
		even: row.even,
		itemStyle: { color: color(row.item) }
	}));
}