/**
 * WP Data Optimizer — One-click User Migration Wizard frontend.
 *
 * - Confirms options + checkbox before starting.
 * - Calls REST endpoints under /wp-json/wpdo/v1/migration/.
 * - Polls /status every 500ms while job is active.
 * - Streams log lines with fade-in; live-updates ratio + progress bar.
 *
 * @since 2.8.0
 */
(function () {
	'use strict';

	const POLL_INTERVAL_MS = 500;
	const config = window.wpdoMigrationWizard || {};
	const i18n = config.i18n || {};
	const restUrl = (config.restUrl || '').replace(/\/$/, '');
	const nonce = config.nonce || '';

	const $ = (id) => document.getElementById(id);

	const root = document.querySelector('.wpdo-migration-wizard');
	if (!root) return;

	const els = {
		runPanel:      $('wpdo-mw-run-panel'),
		progressPanel: $('wpdo-mw-progress-panel'),
		donePanel:     $('wpdo-mw-done-panel'),
		startBtn:      $('wpdo-mw-start'),
		cancelBtn:     $('wpdo-mw-cancel'),
		resumeBtn:     $('wpdo-mw-resume'),
		resetBtn:      $('wpdo-mw-reset'),
		confirmBox:    $('wpdo-mw-confirm-backup'),
		optBackup:     $('wpdo-mw-opt-backup'),
		optStrict:     $('wpdo-mw-opt-strict'),
		opt24h:        $('wpdo-mw-opt-24h'),
		optAsync:      $('wpdo-mw-opt-async'),
		optDryRun:     $('wpdo-mw-opt-dryrun'),
		progressFill:  $('wpdo-mw-progress-fill'),
		progressPct:   $('wpdo-mw-progress-pct'),
		progressTitle: $('wpdo-mw-progress-title'),
		phaseName:     $('wpdo-mw-current-phase-name'),
		elapsed:       $('wpdo-mw-elapsed'),
		liveRatio:     $('wpdo-mw-live-ratio-text'),
		log:           $('wpdo-mw-log'),
		ratio:         $('wpdo-mw-ratio'),
		residue:       $('wpdo-mw-residue'),
		usermeta:      $('wpdo-mw-usermeta'),
		doneSummary:   $('wpdo-mw-done-summary'),
	};

	let pollTimer = null;
	let startedAt = 0;
	let elapsedTimer = null;

	function show(panel) {
		[els.runPanel, els.progressPanel, els.donePanel].forEach((p) => {
			if (!p) return;
			if (p === panel) {
				p.removeAttribute('hidden');
			} else {
				p.setAttribute('hidden', '');
			}
		});
	}

	function fetchJson(path, options = {}) {
		const url = restUrl + path;
		const opts = Object.assign(
			{
				method: 'GET',
				credentials: 'same-origin',
				headers: { 'X-WP-Nonce': nonce, 'Content-Type': 'application/json' },
			},
			options
		);
		return fetch(url, opts).then(async (r) => {
			let body;
			try {
				body = await r.json();
			} catch (e) {
				body = null;
			}
			return { ok: r.ok, status: r.status, body };
		});
	}

	// ── Start handling ───────────────────────────────────────────────────

	if (els.confirmBox && els.startBtn) {
		els.confirmBox.addEventListener('change', () => {
			els.startBtn.disabled = !els.confirmBox.checked;
		});
	}

	if (els.startBtn) {
		els.startBtn.addEventListener('click', () => {
			if (!confirm(i18n.confirmStart || 'Start migration?')) return;
			els.startBtn.disabled = true;
			els.startBtn.textContent = '…';

			const opts = {
				auto_backup:   els.optBackup ? !!els.optBackup.checked : true,
				verify_strict: els.optStrict ? !!els.optStrict.checked : true,
				verify_24h:    els.opt24h    ? !!els.opt24h.checked    : false,
				force_async:   els.optAsync  ? !!els.optAsync.checked  : false,
				dry_run:       els.optDryRun ? !!els.optDryRun.checked : false,
			};

			fetchJson('/migration/start', {
				method: 'POST',
				body: JSON.stringify(opts),
			}).then((res) => {
				if (!res.ok) {
					if (res.body && res.body.reason === 'nothing_to_do') {
						alert(i18n.nothingToDo);
						els.startBtn.disabled = false;
						els.startBtn.textContent = '🚀';
						return;
					}
					alert((res.body && res.body.error) || 'Start failed');
					els.startBtn.disabled = false;
					els.startBtn.textContent = '🚀';
					return;
				}
				startedAt = Date.now();
				show(els.progressPanel);
				startElapsedTimer();
				startPolling();
			});
		});
	}

	// ── Cancel & Resume ──────────────────────────────────────────────────

	if (els.cancelBtn) {
		els.cancelBtn.addEventListener('click', () => {
			if (!confirm(i18n.confirmCancel || 'Cancel?')) return;
			els.cancelBtn.disabled = true;
			fetchJson('/migration/cancel', { method: 'POST' }).then(() => {
				stopPolling();
				stopElapsedTimer();
				setTimeout(() => location.reload(), 600);
			});
		});
	}

	if (els.resumeBtn) {
		els.resumeBtn.addEventListener('click', () => {
			els.resumeBtn.disabled = true;
			fetchJson('/migration/resume', { method: 'POST' }).then((res) => {
				if (res.ok) {
					els.resumeBtn.setAttribute('hidden', '');
					els.cancelBtn.disabled = false;
					startPolling();
				} else {
					alert((res.body && res.body.error) || 'Resume failed');
					els.resumeBtn.disabled = false;
				}
			});
		});
	}

	if (els.resetBtn) {
		els.resetBtn.addEventListener('click', () => location.reload());
	}

	// ── Polling ──────────────────────────────────────────────────────────

	function startPolling() {
		if (pollTimer) return;
		const tick = () => {
			fetchJson('/migration/status').then((res) => {
				if (!res.ok || !res.body) {
					pollTimer = setTimeout(tick, POLL_INTERVAL_MS);
					return;
				}
				renderStatus(res.body);
				const state = res.body.state;
				if (state === 'running') {
					pollTimer = setTimeout(tick, POLL_INTERVAL_MS);
				} else if (state === 'completed') {
					stopPolling();
					stopElapsedTimer();
					renderDone(res.body);
				} else if (state === 'failed') {
					stopPolling();
					stopElapsedTimer();
					renderFailed(res.body);
				} else if (state === 'cancelled' || state === 'idle') {
					stopPolling();
					stopElapsedTimer();
				}
			});
		};
		tick();
	}

	function stopPolling() {
		if (pollTimer) {
			clearTimeout(pollTimer);
			pollTimer = null;
		}
	}

	function startElapsedTimer() {
		if (elapsedTimer) return;
		elapsedTimer = setInterval(() => {
			if (!els.elapsed) return;
			const sec = (Date.now() - startedAt) / 1000;
			els.elapsed.textContent = sec.toFixed(1) + 's';
		}, 100);
	}

	function stopElapsedTimer() {
		if (elapsedTimer) {
			clearInterval(elapsedTimer);
			elapsedTimer = null;
		}
	}

	// ── Render ───────────────────────────────────────────────────────────

	function renderStatus(s) {
		if (els.progressFill) {
			els.progressFill.style.width = (s.overall_progress || 0) + '%';
		}
		if (els.progressPct) {
			els.progressPct.textContent = (s.overall_progress || 0) + '%';
		}
		if (els.phaseName) {
			els.phaseName.textContent = s.phase || '';
		}
		if (els.liveRatio && s.metrics) {
			els.liveRatio.textContent =
				'1:' + (s.metrics.ratio_start || '?') +
				' → 1:' + (s.metrics.ratio_now || '?');
		}
		// Update top metrics live too
		if (els.ratio && s.metrics && s.metrics.ratio_now != null) {
			els.ratio.textContent = '1:' + s.metrics.ratio_now;
		}
		if (els.residue && s.metrics && s.metrics.eav_rows_now != null) {
			els.residue.textContent = String(s.metrics.eav_rows_now);
		}
		updateLog(s.log || []);
	}

	let lastLogLength = 0;
	function updateLog(lines) {
		if (!els.log) return;
		if (lines.length === lastLogLength) return;
		els.log.textContent = lines.join('\n');
		els.log.scrollTop = els.log.scrollHeight;
		lastLogLength = lines.length;
		// Apply a subtle highlight on the last line via CSS animation
		els.log.classList.remove('wpdo-mw-log-flash');
		// Force reflow so re-adding the class re-triggers the animation
		// eslint-disable-next-line no-unused-expressions
		void els.log.offsetWidth;
		els.log.classList.add('wpdo-mw-log-flash');
	}

	function renderDone(s) {
		show(els.donePanel);
		if (!els.doneSummary) return;
		const m = s.metrics || {};
		const elapsed = ((s.completed_at || 0) - (s.started_at || 0));
		els.doneSummary.innerHTML = '';
		const lines = [
			['ratio',   '1:' + (m.ratio_start || '?') + ' → 1:' + (m.ratio_now || '?')],
			['EAV 殘留', (m.eav_rows_start || 0) + ' → ' + (m.eav_rows_now || 0)],
			['mode',   (m.mode_start || '?') + ' → aeav_only'],
			['耗時',   elapsed + ' 秒'],
			['備份',   s.backup_path || '(無)'],
		];
		lines.forEach(([label, value]) => {
			const div = document.createElement('div');
			div.className = 'wpdo-mw-done-line';
			const lab = document.createElement('span'); lab.textContent = label + '：';
			const val = document.createElement('strong'); val.textContent = value;
			div.append(lab, val);
			els.doneSummary.appendChild(div);
		});
	}

	function renderFailed(s) {
		els.progressTitle.textContent = '✗ 失敗 — ' + (i18n.failedRetry || '請 Resume 或 Cancel');
		els.progressTitle.classList.add('wpdo-mw-failed');
		if (els.resumeBtn) {
			els.resumeBtn.removeAttribute('hidden');
			els.resumeBtn.disabled = false;
		}
	}

	// ── On-load: if a job is already running, hop into progress mode ────
	const initialState = root.getAttribute('data-state');
	if (initialState === 'running' || initialState === 'paused') {
		startedAt = Date.now();
		show(els.progressPanel);
		startElapsedTimer();
		startPolling();
	} else if (initialState === 'failed') {
		show(els.progressPanel);
		renderFailed({ state: 'failed' });
	} else if (initialState === 'completed') {
		// Already shown via PHP hidden flag — but populate summary if available
		fetchJson('/migration/status').then((res) => {
			if (res.ok && res.body && res.body.state === 'completed') {
				renderDone(res.body);
			}
		});
	}
})();