// Status-line quota renderer: produces the compact segment shown in the footer.
//
// Format:  <gauge-icon> <braille-5h><braille-7d> <5h%>/<7d%>
// Example: 󰐧 ⣷⣤ 83/23   (claude: 5h=83% green, 7d=23% yellow)
//
// Context-aware: only the windows of the CURRENT model's provider are shown.
// Provider mapping (Pi provider → usage-API provider):
//   anthropic → claude   (5h Session / 7d Weekly)
//   openai    → codex    (5h Window / 7d Window)
//   custom    → (hidden, no quota windows)
//
// Aggregation: MAX remaining fraction across live accounts (not disabled,
// not unavailable) for each 5h/7d window label.
//
// Colors: green ≥70% · yellow 30–69% · red <30%

// The renderer accepts a structural theme type (anything with fg()) so it
// stays decoupled from Pi's internal Theme class.

import type { UsageAccount, UsageDocument, UsageGroup } from "./fetch-usage.ts";

/** nf-md-gauge (Nerd Font Material Design speedometer). */
const GAUGE_ICON = "\u{F0627}";

/** Braille fill chars, 8 levels (empty → full). */
const BRAILLE = ["⡀", "⠂", "⣀", "⣄", "⣤", "⣶", "⣷", "⣾"];

/**
 * Map a Pi provider name to the provider key used by the usage API.
 * Returns null for providers without quota windows (custom providers).
 */
export function providerToUsageKey(piProvider: string): string | null {
	if (piProvider === "anthropic") return "claude";
	if (piProvider === "openai") return "codex";
	return null;
}

/** Is an account "live" — usable and contributing quota? */
function isLiveAccount(a: UsageAccount): boolean {
	return (
		!a.disabled &&
		!a.unavailable &&
		a.supported &&
		Array.isArray(a.groups) &&
		a.groups.length > 0
	);
}

/** Does a group label refer to a 5-hour window? */
function is5hGroup(g: UsageGroup): boolean {
	const s = `${g.id} ${g.label ?? ""}`.toLowerCase();
	return s.includes("5h") || s.includes("five-hour") || s.includes("five hour");
}

/** Does a group label refer to a 7-day window? */
function is7dGroup(g: UsageGroup): boolean {
	const s = `${g.id} ${g.label ?? ""}`.toLowerCase();
	return s.includes("7d") || s.includes("seven-day") || s.includes("seven day");
}

interface WindowAggregate {
	fraction: number;
}

/**
 * Aggregate a window period across live accounts.
 *
 * Semantics: within each account, take the MIN remaining among matching
 * windows (the account's bottleneck for that period — e.g. claude has both
 * a general "7d Weekly" and a model-specific "7d Sonnet" window; the tighter
 * one governs). Then take the MAX across accounts (the router will dispatch
 * to the account with the most headroom).
 */
function aggregateWindow(
	accounts: UsageAccount[],
	predicate: (g: UsageGroup) => boolean,
): WindowAggregate | null {
	let maxAcross = -1;
	for (const a of accounts) {
		if (!isLiveAccount(a)) continue;
		let minWithin = Infinity;
		for (const g of a.groups ?? []) {
			if (predicate(g)) {
				if (g.remainingFraction < minWithin) minWithin = g.remainingFraction;
			}
		}
		if (minWithin !== Infinity && minWithin > maxAcross) {
			maxAcross = minWithin;
		}
	}
	if (maxAcross < 0) return null;
	return { fraction: clamp(maxAcross) };
}

function clamp(f: number): number {
	return Math.max(0, Math.min(1, f));
}

/** Braille fill char for a given fraction (8 levels). */
function brailleFor(fraction: number): string {
	const idx = Math.min(
		BRAILLE.length - 1,
		Math.floor(fraction * BRAILLE.length),
	);
	return BRAILLE[idx]!;
}

/** Theme color name for a given remaining fraction. */
function colorForFraction(fraction: number): "success" | "warning" | "error" {
	if (fraction >= 0.7) return "success";
	if (fraction >= 0.3) return "warning";
	return "error";
}

/** Percent as integer string (0–100). */
function pct(fraction: number): number {
	return Math.round(fraction * 100);
}

/**
 * Render the quota status segment for the current provider, or null if the
 * provider has no quota windows (segment should be hidden).
 *
 * @param doc     - usage document from /api/usage
 * @param piProvider - Pi provider name of the current model (e.g. "anthropic")
 * @param theme   - Pi theme for coloring (from ctx.ui.theme)
 */
export function renderQuotaSegment(
	doc: UsageDocument,
	piProvider: string,
	// eslint-disable-next-line @typescript-eslint/no-explicit-any
	theme: {
		fg(color: "success" | "warning" | "error" | "dim", text: string): string;
	},
): string | null {
	const usageKey = providerToUsageKey(piProvider);
	if (!usageKey) return null;

	const accounts = doc.accounts.filter((a) => a.provider === usageKey);
	if (accounts.length === 0) return null;

	const w5 = aggregateWindow(accounts, is5hGroup);
	const w7 = aggregateWindow(accounts, is7dGroup);

	// No 5h/7d windows found → hide the segment entirely
	if (!w5 && !w7) return null;

	const parts: string[] = [theme.fg("dim", GAUGE_ICON)];

	if (w5) {
		parts.push(
			`${theme.fg("dim", "5h")} ${theme.fg(colorForFraction(w5.fraction), brailleFor(w5.fraction))} ${theme.fg(colorForFraction(w5.fraction), String(pct(w5.fraction)))}`,
		);
	}
	if (w7) {
		parts.push(
			`${theme.fg("dim", "7d")} ${theme.fg(colorForFraction(w7.fraction), brailleFor(w7.fraction))} ${theme.fg(colorForFraction(w7.fraction), String(pct(w7.fraction)))}`,
		);
	}

	return parts.join(" ");
}