import { formatCount } from "../format-helpers.ts";
import { formatHint } from "../rail.ts";
import type { RunUiSnapshot } from "../snapshot-types.ts";

export function renderMailboxPane(snapshot: RunUiSnapshot | undefined): string[] {
	if (!snapshot) return ["Mailbox pane: snapshot unavailable"];
	const mailbox = snapshot.mailbox;
	const approx = mailbox.approximate ? " · approximate (tail)" : "";
	const unread = mailbox.inboxUnread ?? 0;
	const outgoing = mailbox.outboxPending ?? 0;
	const attention = mailbox.needsAttention ?? 0;
	// L7 dialect: counts speak the compactUsage TUI form (the `↑2.8k ↓3.7k`
	// pattern from live-run-sidebar.ts), NOT the `unread=2` wire format. ↓ =
	// received (inbox), ↑ = sent (outbox pending); ⚠ marks attention (the same
	// pane-local warning glyph the steering line below already uses).
	const lines: string[] = [`Mailbox pane: ↓${unread} unread · ↑${outgoing} pending · ⚠${attention} attention${approx}`];
	// Kind-separated breakdown — every kind here is an inbox (received) count.
	const kindParts: string[] = [];
	const steer = mailbox.steerUnread ?? 0;
	const followUp = mailbox.followUpUnread ?? 0;
	const response = mailbox.responseUnread ?? 0;
	const message = mailbox.messageUnread ?? 0;
	if (steer > 0) kindParts.push(`↓${steer} steer`);
	if (followUp > 0) kindParts.push(`↓${followUp} follow-up`);
	if (response > 0) kindParts.push(`↓${response} response`);
	if (message > 0) kindParts.push(`↓${message} message`);
	if (kindParts.length > 0) {
		lines.push(`  Breakdown: ${kindParts.join(" · ")}`);
		if (steer > 0) {
			lines.push("  ⚠ Urgent: steering messages require immediate attention.");
		}
		if (followUp > 0) {
			lines.push(`  📋 ${formatCount(followUp, "follow-up")} pending review.`);
		}
	}
	if (attention > 0) {
		// One hint format (rail.ts `formatHint`): keys `label` joined by ` · `.
		lines.push(
			`Needs attention: press ${formatHint([
				["Enter", "for detail"],
				["A", "ack"],
				["N", "nudge"],
				["C", "compose"],
				["X", "ack all"],
			])}.`,
		);
	} else {
		lines.push(
			`No mailbox items need attention. Press ${formatHint([
				["Enter", "for detail"],
				["C", "compose"],
			])}.`,
		);
	}
	return lines;
}