/**
 * WPDO Entity Bridge — Admin UI controller
 *
 * Features:
 * - Polls /wp-json/wpdo/v1/entity-bridge/health every 5 s during active backfill
 * - Updates coverage progress bars and migration badges in real time
 * - Handles Backfill / Promote / Demote button clicks with confirmation
 *
 * Depends on: wpdoEntityBridge (wp_localize_script data)
 */

/* global wpdoEntityBridge */
( function () {
	'use strict';

	var cfg = window.wpdoEntityBridge || {};
	var restUrl = cfg.restUrl || '';
	var nonce   = cfg.nonce   || '';
	var pollInterval = 5000;   // ms between polls
	var timer         = null;
	var activeBackfills = {};  // {entity_type: {group_name: true}} — track in-progress

	// ─── Helpers ─────────────────────────────────────────────────────────────

	function apiFetch( method, path, body ) {
		var url = restUrl + path;
		var opts = {
			method:  method,
			headers: {
				'Content-Type': 'application/json',
				'X-WP-Nonce':   nonce,
			},
		};
		if ( body ) {
			opts.body = JSON.stringify( body );
		}
		return fetch( url, opts ).then( function ( res ) {
			if ( ! res.ok ) {
				return res.json().then( function ( e ) { throw new Error( e.message || e.error || res.status ); } );
			}
			return res.json();
		} );
	}

	function modeBadgeClass( mode ) {
		return {
			disabled:    'wpdo-mode-disabled',
			dual_write:  'wpdo-mode-dual-write',
			shadow_read: 'wpdo-mode-shadow-read',
			aeav_only:   'wpdo-mode-aeav-only',
		}[ mode ] || 'wpdo-mode-disabled';
	}

	function modeLabel( mode ) {
		return {
			disabled:    'disabled',
			dual_write:  'dual_write',
			shadow_read: 'shadow_read',
			aeav_only:   'aeav_only',
		}[ mode ] || mode;
	}

	function pct( n ) {
		return Math.min( 100, Math.max( 0, parseFloat( n ) || 0 ) ).toFixed( 1 );
	}

	// ─── Update UI from health data ──────────────────────────────────────────

	function updateAll( data ) {
		var hasActive = false;

		Object.keys( data ).forEach( function ( type ) {
			var card = document.querySelector( '[data-entity-type="' + type + '"]' );
			if ( ! card ) return;

			var info = data[ type ];

			// Mode badge
			var badge = card.querySelector( '.wpdo-mode-badge' );
			if ( badge ) {
				badge.textContent    = modeLabel( info.mode );
				badge.className      = 'wpdo-mode-badge ' + modeBadgeClass( info.mode );
			}

			// Pipeline dots
			var pipeline = card.querySelector( '.wpdo-pipeline' );
			if ( pipeline ) {
				pipeline.innerHTML = buildPipeline( info.mode );
			}

			// Mode days
			var daysEl = card.querySelector( '.wpdo-mode-days' );
			if ( daysEl ) {
				daysEl.textContent = info.mode_days + ' 天';
			}

			// Groups
			( info.groups || [] ).forEach( function ( g ) {
				var groupEl = card.querySelector( '[data-group="' + g.name + '"]' );
				if ( ! groupEl ) return;

				// Progress bar
				var bar = groupEl.querySelector( '.wpdo-cov-bar-fill' );
				if ( bar ) bar.style.width = pct( g.coverage_pct ) + '%';

				var pctEl = groupEl.querySelector( '.wpdo-cov-pct' );
				if ( pctEl ) pctEl.textContent = pct( g.coverage_pct ) + '%';

				var rowsEl = groupEl.querySelector( '.wpdo-cov-rows' );
				if ( rowsEl ) rowsEl.textContent = g.flat_rows + ' / ' + g.eav_rows;

				// Migration badge
				var migBadge = groupEl.querySelector( '.wpdo-mig-status' );
				if ( migBadge ) {
					migBadge.textContent = g.migration_status;
					migBadge.className   = 'wpdo-mig-status wpdo-mig-' + g.migration_status.replace( /_/g, '-' );
				}

				// Is this group's backfill active?
				if ( g.migration_status === 'running' ) {
					hasActive = true;
				}
			} );

			// Shadow diffs
			var diffsEl = card.querySelector( '.wpdo-shadow-diffs' );
			if ( diffsEl ) diffsEl.textContent = info.shadow_diffs;

			// Recommendation
			var recEl = card.querySelector( '.wpdo-recommendation' );
			if ( recEl ) recEl.textContent = info.recommendation;

			// Auto-promote eligible badge
			var apEl = card.querySelector( '.wpdo-auto-promote-eligible' );
			if ( apEl ) {
				if ( info.auto_promote && info.auto_promote.eligible ) {
					apEl.textContent  = '✓ 可升級';
					apEl.style.color  = '#155724';
				} else {
					apEl.textContent  = '— ' + ( ( info.auto_promote || {} ).reason || '' );
					apEl.style.color  = '#856404';
				}
			}

			// Button states — update promote/demote targets
			var promoteBtn = card.querySelector( '.wpdo-btn-promote' );
			if ( promoteBtn ) {
				promoteBtn.disabled         = ! info.next_mode;
				promoteBtn.dataset.nextMode = info.next_mode || '';
				promoteBtn.title            = info.next_mode ? '升級到 ' + info.next_mode : '已在最高模式';
			}

			var demoteBtn = card.querySelector( '.wpdo-btn-demote' );
			if ( demoteBtn ) {
				demoteBtn.disabled         = ! info.prev_mode;
				demoteBtn.dataset.prevMode = info.prev_mode || '';
				demoteBtn.title            = info.prev_mode ? '降級到 ' + info.prev_mode : '已在最低模式';
			}

			// Backfill active indicator
			if ( info.backfill_active ) hasActive = true;
		} );

		// Manage poll timer
		if ( hasActive ) {
			startPolling();
		}
	}

	function buildPipeline( currentMode ) {
		var modes = [ 'disabled', 'dual_write', 'shadow_read', 'aeav_only' ];
		var labels = { disabled: 'disabled', dual_write: 'dual_write', shadow_read: 'shadow_read', aeav_only: 'aeav_only' };
		return modes.map( function ( m ) {
			var active = m === currentMode ? ' wpdo-pipeline-active' : '';
			return '<span class="wpdo-pipeline-dot' + active + '" title="' + labels[ m ] + '">' +
				'<span class="wpdo-dot"></span>' +
				'<span class="wpdo-dot-label">' + labels[ m ] + '</span>' +
				'</span>';
		} ).join( '<span class="wpdo-pipeline-arrow">→</span>' );
	}

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

	function poll() {
		apiFetch( 'GET', '/entity-bridge/health' )
			.then( updateAll )
			.catch( function ( e ) { console.warn( '[WPDO] Health poll error:', e ); } );
	}

	function startPolling() {
		if ( timer ) return;
		timer = setInterval( poll, pollInterval );
	}

	function stopPolling() {
		if ( timer ) { clearInterval( timer ); timer = null; }
	}

	// ─── Button handlers ─────────────────────────────────────────────────────

	function handleBackfill( btn ) {
		var entityType = btn.dataset.entityType;
		var groupName  = btn.dataset.groupName;
		if ( ! confirm( '確定要啟動 ' + entityType + '/' + groupName + ' 的 Backfill 遷移嗎？這將清除現有進度並重新開始。' ) ) return;

		btn.disabled     = true;
		btn.textContent  = '排程中…';

		apiFetch( 'POST', '/entity-bridge/backfill', { entity_type: entityType, group_name: groupName } )
			.then( function () {
				btn.textContent = '已排程 ✓';
				startPolling();
				// Refresh once immediately
				setTimeout( poll, 1000 );
			} )
			.catch( function ( e ) {
				alert( '啟動 Backfill 失敗：' + e.message );
				btn.disabled    = false;
				btn.textContent = '啟動 Backfill';
			} );
	}

	function handlePromote( btn ) {
		var entityType = btn.dataset.entityType;
		var nextMode   = btn.dataset.nextMode;
		if ( ! nextMode ) return;

		if ( ! confirm( '確定要將 ' + entityType + ' 升級到 ' + nextMode + ' 嗎？' ) ) return;

		btn.disabled    = true;
		btn.textContent = '更新中…';

		apiFetch( 'POST', '/entity-bridge/promote', { entity_type: entityType } )
			.then( function () {
				poll();   // immediate refresh
			} )
			.catch( function ( e ) {
				alert( '升級失敗：' + e.message );
				btn.disabled    = false;
				btn.textContent = '升級模式';
			} );
	}

	function handleDemote( btn ) {
		var entityType = btn.dataset.entityType;
		var prevMode   = btn.dataset.prevMode;
		if ( ! prevMode ) return;

		if ( ! confirm( '確定要將 ' + entityType + ' 降級到 ' + prevMode + ' 嗎？降級後讀取會切回 EAV。' ) ) return;

		btn.disabled    = true;
		btn.textContent = '更新中…';

		apiFetch( 'POST', '/entity-bridge/demote', { entity_type: entityType } )
			.then( function () {
				poll();
			} )
			.catch( function ( e ) {
				alert( '降級失敗：' + e.message );
				btn.disabled    = false;
				btn.textContent = '降級模式';
			} );
	}

	// ─── Event delegation ────────────────────────────────────────────────────

	document.addEventListener( 'click', function ( e ) {
		var btn = e.target.closest( 'button[data-wpdo-action]' );
		if ( ! btn ) return;

		var action = btn.dataset.wpdoAction;

		if ( action === 'backfill' ) {
			handleBackfill( btn );
		} else if ( action === 'promote' ) {
			handlePromote( btn );
		} else if ( action === 'demote' ) {
			handleDemote( btn );
		}
	} );

	// ─── Init ────────────────────────────────────────────────────────────────

	// Initial poll on page load if we're on the entity-bridge tab.
	if ( document.querySelector( '.wpdo-entity-bridge-tab' ) ) {
		poll();

		// Auto-start polling if any backfill is already running (check server state).
		// A subsequent poll() response will call startPolling() if needed.
	}

	// Stop polling when navigating away.
	window.addEventListener( 'beforeunload', stopPolling );

} )();