/**
 * GM-facing orchestration: the End Session flow and the bulk
 * snapshot push it depends on. Imported by main.js and exposed on
 * `globalThis.seitimeBridge` for use from Foundry macros.
 *
 * Recommended macro body (Script type, no arguments):
 *   seitimeBridge.endSession();
 */

import { MODULE_ID } from "./constants.js";
import {
	completeSession,
	finalizeAttendance,
	getSessionRoster,
	listScheduledSessions,
	pushModuleInventory,
	pushSnapshot,
} from "./api.js";

function escapeHtml(s) {
	return String(s ?? "").replace(
		/[&<>"']/g,
		(c) => ({ "&": "&amp;", "<": "&lt;", ">": "&gt;", '"': "&quot;", "'": "&#39;" })[c],
	);
}

/**
 * Activity check used by the attendance proposal: an actor counts as "active"
 * for this session if its data was modified during the session window, or if
 * a non-GM owner is currently online when End Session is run.
 */
function actorWasActive(actor, sessionStartMs) {
	if (!actor) return false;
	const mod = actor.system?._stats?.modifiedTime ?? actor._stats?.modifiedTime ?? 0;
	if (sessionStartMs && mod >= sessionStartMs) return true;
	const ownership = actor.ownership ?? {};
	for (const [userId, level] of Object.entries(ownership)) {
		if (userId === "default") continue;
		if (level < CONST.DOCUMENT_OWNERSHIP_LEVELS.OWNER) continue;
		const user = game.users.get(userId);
		if (user && !user.isGM && user.active) return true;
	}
	return false;
}

/**
 * Build an attendance proposal from a Frappe roster payload + current
 * Foundry state. Returns the same player rows with a `proposed_status`
 * field set:
 *   - Players whose status is anything other than "Signed Up" keep it.
 *   - "Signed Up" players become "Present" if any of their linked
 *     characters' actors show activity this session, else "No Show".
 *
 * The proposal is a default-correct starting point for the GM-facing
 * dialog; every row remains overridable.
 */
export function proposeAttendance(roster) {
	const sessionStartMs = roster.session_start ? Date.parse(roster.session_start) : 0;
	return (roster.players ?? []).map((p) => {
		if (p.status !== "Signed Up") {
			return { ...p, proposed_status: p.status };
		}
		const anyActive = (p.characters ?? []).some((c) =>
			actorWasActive(game.actors.get(c.foundry_actor_id), sessionStartMs),
		);
		return { ...p, proposed_status: anyActive ? "Present" : "No Show" };
	});
}

/**
 * Show the attendance confirmation dialog. Resolves to the final attendance
 * array `[{player, status}]` on Confirm, or null on Cancel. An empty roster
 * resolves to `[]` immediately without showing a dialog.
 *
 * The dropdown is restricted to Present / Notice / No Show — every row must
 * be finalized in this flow. The GM can still rerun End Session later if
 * they want to revise (the Frappe handler accepts updates).
 */
async function showAttendanceDialog(proposal) {
	if (!proposal.length) return [];

	const STATUS_OPTIONS = ["Present", "Notice", "No Show"];
	const rows = proposal
		.map((p, i) => {
			const characters =
				(p.characters ?? []).map((c) => escapeHtml(c.character)).join(", ") ||
				"<em style=\"color:#888\">—</em>";
			const opts = STATUS_OPTIONS.map(
				(s) =>
					`<option value="${s}"${s === p.proposed_status ? " selected" : ""}>${s}</option>`,
			).join("");
			return `
				<tr>
					<td style="padding:0.25em;">${escapeHtml(p.label)}</td>
					<td style="padding:0.25em; color:#666; font-size:0.9em;">${characters}</td>
					<td style="padding:0.25em;">
						<select data-player="${escapeHtml(p.player)}" data-row="${i}">${opts}</select>
					</td>
				</tr>
			`;
		})
		.join("");

	return new Promise((resolve) => {
		new Dialog(
			{
				title: "Finalize Attendance",
				content: `
					<p>Confirm each player's attendance for this session.</p>
					<table style="width:100%; border-collapse:collapse;">
						<thead>
							<tr style="border-bottom:1px solid #ccc;">
								<th style="text-align:left; padding:0.25em;">Player</th>
								<th style="text-align:left; padding:0.25em;">Character(s)</th>
								<th style="text-align:left; padding:0.25em; width:9em;">Status</th>
							</tr>
						</thead>
						<tbody>${rows}</tbody>
					</table>
				`,
				buttons: {
					cancel: { label: "Cancel", callback: () => resolve(null) },
					confirm: {
						label: "Confirm",
						callback: (html) => {
							const result = [];
							html.find("select[data-player]").each(function () {
								result.push({
									player: $(this).data("player"),
									status: $(this).val(),
								});
							});
							resolve(result);
						},
					},
				},
				default: "confirm",
				close: () => resolve(null),
			},
			{ width: 560 },
		).render(true);
	});
}

/**
 * Push snapshots for every PC in the world, in parallel. Returns a summary
 * with successful/failed counts and the names of any failures so the caller
 * can surface them.
 */
export async function pushAllSnapshots() {
	const pcs = game.actors.filter((a) => a.type === "character");
	const results = await Promise.allSettled(pcs.map((a) => pushSnapshot(a)));
	const failed = results
		.map((r, i) => (r.status === "rejected" ? { name: pcs[i].name, error: r.reason?.message ?? String(r.reason) } : null))
		.filter(Boolean);
	return {
		total: pcs.length,
		successful: pcs.length - failed.length,
		failed,
	};
}

/**
 * Show the appropriate dialog for the number of candidates and resolve to
 * the chosen session_id, or null if the user cancels.
 */
async function pickSession(sessions) {
	if (sessions.length === 1) {
		const s = sessions[0];
		const confirmed = await Dialog.confirm({
			title: "End Session",
			content: `
				<p>End <b>${escapeHtml(s.session_title)}</b>?</p>
				<p>This will mark it Completed, schedule the next session, and push snapshots for all PCs.</p>
			`,
			yes: () => true,
			no: () => false,
			defaultYes: true,
		});
		return confirmed ? s.session_id : null;
	}

	const options = sessions
		.map(
			(s) =>
				`<option value="${escapeHtml(s.session_id)}">${escapeHtml(s.session_title)}${s.session_start ? ` — ${escapeHtml(s.session_start)}` : ""}</option>`,
		)
		.join("");

	return new Promise((resolve) => {
		new Dialog({
			title: "End Session",
			content: `
				<p>Multiple scheduled sessions match this Foundry world. Pick one to end:</p>
				<select id="seitime-session-pick" style="width:100%; margin-bottom:0.5em;">
					${options}
				</select>
			`,
			buttons: {
				cancel: { label: "Cancel", callback: () => resolve(null) },
				end: {
					label: "End Session",
					callback: (html) => {
						const value = html.find("#seitime-session-pick").val();
						resolve(value || null);
					},
				},
			},
			default: "end",
			close: () => resolve(null),
		}).render(true);
	});
}

function summarizeAttendance(attendance) {
	const counts = { Present: 0, Notice: 0, "No Show": 0, "Signed Up": 0 };
	for (const a of attendance) counts[a.status] = (counts[a.status] ?? 0) + 1;
	const order = ["Present", "Notice", "No Show", "Signed Up"];
	return order
		.filter((k) => counts[k])
		.map((k) => `${counts[k]} ${k}`)
		.join(", ");
}

function buildSummaryHtml(completion, snapshotResult, moduleResult, attendance) {
	const parts = [
		`<h3>Session Complete</h3>`,
		`<p><b>${escapeHtml(completion.completed_session)}</b> marked Completed.</p>`,
	];
	if (attendance?.length) {
		parts.push(`<p>Attendance: ${escapeHtml(summarizeAttendance(attendance))}.</p>`);
	}
	if (completion.next_session) {
		parts.push(
			`<p>Next session scheduled: <b>${escapeHtml(completion.next_session)}</b> (#${escapeHtml(completion.next_session_number)}).</p>`,
		);
	}
	parts.push(
		`<p>Snapshots pushed: ${snapshotResult.successful} of ${snapshotResult.total}.</p>`,
	);
	if (snapshotResult.failed.length) {
		const items = snapshotResult.failed
			.map((f) => `<li>${escapeHtml(f.name)}: ${escapeHtml(f.error)}</li>`)
			.join("");
		parts.push(`<p style="color:#a00"><b>Failed pushes:</b></p><ul>${items}</ul>`);
	}
	if (moduleResult?.upserted) {
		parts.push(
			`<p>Tracked ${moduleResult.upserted} active module(s) for credits.</p>`,
		);
	} else if (moduleResult?.error) {
		parts.push(
			`<p style="color:#a00">Module inventory push failed: ${escapeHtml(moduleResult.error)}</p>`,
		);
	}
	return parts.join("");
}

/**
 * Full end-of-session flow. Invoked from a Foundry macro by the GM.
 */
export async function endSession() {
	if (!game.user.isGM) {
		ui.notifications.warn("End Session is GM-only.");
		return;
	}

	let sessions;
	try {
		sessions = await listScheduledSessions();
	} catch (err) {
		console.error(`[${MODULE_ID}]`, err);
		ui.notifications.error(`Could not fetch scheduled sessions: ${err.message}`);
		return;
	}

	if (!sessions.length) {
		ui.notifications.warn(
			"No scheduled sessions found for this Foundry world. Check that the world ID matches a Game in Frappe.",
		);
		return;
	}

	const sessionId = await pickSession(sessions);
	if (!sessionId) return;

	let roster;
	try {
		roster = await getSessionRoster(sessionId);
	} catch (err) {
		console.error(`[${MODULE_ID}]`, err);
		ui.notifications.error(`Could not fetch session roster: ${err.message}`);
		return;
	}

	const proposal = proposeAttendance(roster);
	const attendance = await showAttendanceDialog(proposal);
	if (attendance === null) return;

	// Finalize attendance BEFORE marking the session Completed so that a
	// failure here leaves the session Scheduled and re-runnable, rather
	// than Completed with no attendance recorded.
	try {
		await finalizeAttendance(sessionId, attendance);
	} catch (err) {
		console.error(`[${MODULE_ID}]`, err);
		ui.notifications.error(`Could not finalize attendance: ${err.message}`);
		return;
	}

	let completion;
	try {
		completion = await completeSession(sessionId);
	} catch (err) {
		console.error(`[${MODULE_ID}]`, err);
		ui.notifications.error(`Could not complete session: ${err.message}`);
		return;
	}

	const snapshotResult = await pushAllSnapshots();

	// Module inventory is non-critical — log and continue if the push fails
	// so the session still gets marked Completed with a clean summary.
	let moduleResult = null;
	try {
		const raw = await pushModuleInventory();
		moduleResult = raw?.message ?? null;
	} catch (err) {
		console.warn(`[${MODULE_ID}] module inventory push failed:`, err);
		moduleResult = { error: err.message };
	}

	await ChatMessage.create({
		content: buildSummaryHtml(completion, snapshotResult, moduleResult, attendance),
		speaker: { alias: "Seitime Bridge" },
		whisper: ChatMessage.getWhisperRecipients("GM").map((u) => u.id),
	});

	const failureNote = snapshotResult.failed.length ? ` (${snapshotResult.failed.length} snapshot push(es) failed — see chat)` : "";
	ui.notifications.info(`Session ended. ${snapshotResult.successful}/${snapshotResult.total} snapshots pushed${failureNote}.`);
}