/**
 * Model picker popup for PRAutoBlogger admin settings.
 *
 * Fetches the OpenRouter model registry via AJAX, then renders a searchable,
 * sortable popup overlay when the user clicks a model-select trigger button.
 * Columns: Model, Price (in / out per 1M tokens), Context window.
 * Each column header is clickable to sort ascending/descending.
 *
 * @see admin/class-admin-page.php — Renders model_select fields and localizes config.
 * @see services/class-open-router-model-registry.php — Server-side registry source.
 */
(function ($) {
	'use strict';

	var config          = window.prautobloggerAdmin || {};
	var cachedModels    = null;
	var fetchInProgress = null;

	// Persists across open/close so the user's preferred sort is remembered.
	var sortState = { col: 'name', dir: 'asc' };

	/**
	 * Fetch models from the server (cached after first call).
	 *
	 * @param {string} capability Filter capability (e.g. 'text→text').
	 * @return {jQuery.Deferred} Resolves with model array.
	 */
	function fetchModels( capability ) {
		// Image models are embedded in the page config — no AJAX needed.
		if ( capability === 'image_generation' ) {
			var imgModels = config.imageModels || [];
			return $.Deferred().resolve( imgModels );
		}

		if ( cachedModels ) {
			return $.Deferred().resolve( filterModels( cachedModels, capability ) );
		}

		if ( fetchInProgress ) {
			return fetchInProgress.then( function () {
				return filterModels( cachedModels, capability );
			} );
		}

		fetchInProgress = $.ajax( {
			url:    config.ajaxUrl,
			method: 'POST',
			data: {
				action: 'prautoblogger_get_models',
				nonce:  config.modelsNonce
			},
			timeout: 15000
		} ).then( function ( response ) {
			fetchInProgress = null;
			if ( response.success && Array.isArray( response.data ) ) {
				cachedModels = response.data;
				return filterModels( cachedModels, capability );
			}
			cachedModels = [];
			return [];
		}, function () {
			fetchInProgress = null;
			cachedModels    = [];
			return [];
		} );

		return fetchInProgress;
	}

	/**
	 * Filter model array by capability.
	 *
	 * @param {Array}  models     Full model list.
	 * @param {string} capability Capability string to match.
	 * @return {Array} Filtered models.
	 */
	function filterModels( models, capability ) {
		if ( ! capability ) return models;
		return models.filter( function ( m ) {
			return m.capabilities && m.capabilities.indexOf( capability ) !== -1;
		} );
	}

	/**
	 * Sort a model array according to the current sortState.
	 * Deprecated models always sink to the bottom regardless of column.
	 *
	 * @param {Array} arr Model array to sort (not mutated — returns a new array).
	 * @return {Array} Sorted copy.
	 */
	function applySort( arr ) {
		var col = sortState.col;
		var dir = sortState.dir;

		return arr.slice().sort( function ( a, b ) {
			// Deprecated always last.
			if ( a.deprecated !== b.deprecated ) {
				return a.deprecated ? 1 : -1;
			}

			var valA, valB;

			if ( col === 'price' ) {
				// Image models use cost_per_image; text models use input_price_per_m.
				valA = ( a.cost_per_image !== undefined ) ? a.cost_per_image : ( a.input_price_per_m || 0 );
				valB = ( b.cost_per_image !== undefined ) ? b.cost_per_image : ( b.input_price_per_m || 0 );
			} else if ( col === 'context' ) {
				valA = a.context_length || 0;
				valB = b.context_length || 0;
			} else {
				// Default: sort by model name.
				valA = ( a.name || '' ).toLowerCase();
				valB = ( b.name || '' ).toLowerCase();
			}

			if ( valA < valB ) return dir === 'asc' ? -1 : 1;
			if ( valA > valB ) return dir === 'asc' ? 1  : -1;
			return 0;
		} );
	}

	/**
	 * Format a price-per-million-tokens value for display.
	 *
	 * @param {number} price Price per 1M tokens.
	 * @return {string} Formatted string like "$0.25" or "Free".
	 */
	function formatPrice( price ) {
		if ( ! price || price <= 0 ) return 'Free';
		if ( price < 0.01 )         return '$' + price.toFixed( 4 );
		if ( price < 1 )            return '$' + price.toFixed( 2 );
		return '$' + price.toFixed( 2 );
	}

	/**
	 * Format context length for display.
	 *
	 * @param {number} ctx Context length in tokens.
	 * @return {string} Formatted string like "128K" or "1M".
	 */
	function formatContext( ctx ) {
		if ( ! ctx )          return '—';
		if ( ctx >= 1000000 ) return ( ctx / 1000000 ).toFixed( 0 ) + 'M';
		if ( ctx >= 1000 )    return Math.round( ctx / 1000 ) + 'K';
		return ctx.toString();
	}

	/**
	 * Build HTML for a single model row in the picker list.
	 *
	 * @param {Object} model Normalized model record.
	 * @return {string} HTML string.
	 */
	function renderModelRow( model ) {
		var deprecated   = model.deprecated ? ' ab-mp-deprecated' : '';
		var isImageModel = model.cost_per_image !== undefined && model.cost_per_image > 0;
		var priceHtml, priceTitle, metaRight;

		if ( isImageModel ) {
			priceHtml  = '$' + model.cost_per_image.toFixed( 4 ) + '/image';
			priceTitle = 'Cost per generated image';
			metaRight  = model.description
				? '<span class="ab-mp-ctx" title="Details">' + escHtml( model.description ) + '</span>'
				: '';
		} else {
			priceHtml  = formatPrice( model.input_price_per_m ) + ' / ' + formatPrice( model.output_price_per_m );
			priceTitle = 'Input / Output per 1M tokens';
			metaRight  = '<span class="ab-mp-ctx" title="Context window">' + formatContext( model.context_length ) + '</span>';
		}

		return (
			'<div class="ab-mp-row' + deprecated + '" data-model-id="' + escAttr( model.id ) + '">' +
				'<div class="ab-mp-row-main">' +
					'<span class="ab-mp-name">' + escHtml( model.name ) + '</span>' +
					'<span class="ab-mp-provider">' + escHtml( model.provider ) + '</span>' +
					( model.deprecated ? '<span class="ab-mp-dep-badge">deprecated</span>' : '' ) +
				'</div>' +
				'<div class="ab-mp-row-meta">' +
					metaRight +
					'<span class="ab-mp-price" title="' + priceTitle + '">' + priceHtml + '</span>' +
				'</div>' +
			'</div>'
		);
	}

	/** Minimal HTML escaping for display. */
	function escHtml( str ) {
		if ( ! str ) return '';
		return str.replace( /&/g, '&amp;' ).replace( /</g, '&lt;' ).replace( />/g, '&gt;' );
	}

	/** Escape a string for use in an HTML attribute. */
	function escAttr( str ) {
		return escHtml( str ).replace( /"/g, '&quot;' );
	}

	/**
	 * Open the model picker popup for a given trigger button.
	 *
	 * @param {jQuery} $trigger The .ab-mp-trigger button that was clicked.
	 */
	function openPicker( $trigger ) {
		var fieldId    = $trigger.data( 'field-id' );
		var capability = $trigger.data( 'capability' ) || '';

		var isImageCap = capability === 'image_generation';
		var priceLabel = isImageCap ? 'Cost per generated image' : 'Prices per 1M tokens (in / out)';

		// ── Build overlay + popup ───────────────────────────────────────
		var $overlay = $( '<div class="ab-mp-overlay"></div>' );
		var $popup   = $(
			'<div class="ab-mp-popup">' +
				'<div class="ab-mp-header">' +
					'<span class="ab-mp-title">Select Model</span>' +
					'<button type="button" class="ab-mp-close">&times;</button>' +
				'</div>' +
				'<div class="ab-mp-search-wrap">' +
					'<input type="text" class="ab-mp-search" placeholder="Search models…" autocomplete="off" />' +
				'</div>' +
				'<div class="ab-mp-col-headers">' +
					'<button type="button" class="ab-mp-col-header ab-mp-col-model" data-col="name">Model <span class="ab-mp-sort-arrow"></span></button>' +
					'<div class="ab-mp-col-headers-meta">' +
						'<button type="button" class="ab-mp-col-header ab-mp-col-ctx" data-col="context">Context <span class="ab-mp-sort-arrow"></span></button>' +
						'<button type="button" class="ab-mp-col-header ab-mp-col-price" data-col="price">Price (in / out) <span class="ab-mp-sort-arrow"></span></button>' +
					'</div>' +
				'</div>' +
				'<div class="ab-mp-list"><div class="ab-mp-loading">Loading models…</div></div>' +
				'<div class="ab-mp-footer">' +
					'<span class="ab-mp-count"></span>' +
					'<span class="ab-mp-price-label">' + priceLabel + '</span>' +
				'</div>' +
			'</div>'
		);

		$overlay.append( $popup );
		$( 'body' ).append( $overlay );

		var $search      = $popup.find( '.ab-mp-search' );
		var $list        = $popup.find( '.ab-mp-list' );
		var $count       = $popup.find( '.ab-mp-count' );
		var $colHeaders  = $popup.find( '.ab-mp-col-headers' );
		var allModels    = [];
		var currentQuery = '';

		// Focus search after render.
		setTimeout( function () { $search.focus(); }, 50 );

		// ── Sort header indicators ──────────────────────────────────────
		/** Update active-column highlight and sort arrow glyphs. */
		function updateSortHeaders() {
			$colHeaders.find( '.ab-mp-col-header' ).each( function () {
				var col    = $( this ).data( 'col' );
				var $arrow = $( this ).find( '.ab-mp-sort-arrow' );
				if ( col === sortState.col ) {
					$( this ).addClass( 'ab-mp-col-active' );
					$arrow.text( sortState.dir === 'asc' ? ' ▲' : ' ▼' );
				} else {
					$( this ).removeClass( 'ab-mp-col-active' );
					$arrow.text( ' ⇅' );
				}
			} );
		}

		// ── Render ──────────────────────────────────────────────────────
		/** Render filtered + sorted model list. */
		function renderList( models, query ) {
			var filtered = models;
			if ( query ) {
				var q = query.toLowerCase();
				filtered = models.filter( function ( m ) {
					return ( m.name     && m.name.toLowerCase().indexOf( q )     !== -1 ) ||
					       ( m.id       && m.id.toLowerCase().indexOf( q )       !== -1 ) ||
					       ( m.provider && m.provider.toLowerCase().indexOf( q ) !== -1 );
				} );
			}

			filtered = applySort( filtered );

			if ( filtered.length === 0 ) {
				$list.html( '<div class="ab-mp-empty">No models found.</div>' );
			} else {
				var html = '';
				for ( var i = 0; i < filtered.length; i++ ) {
					html += renderModelRow( filtered[ i ] );
				}
				$list.html( html );
			}
			$count.text( filtered.length + ' model' + ( filtered.length !== 1 ? 's' : '' ) );
			updateSortHeaders();
		}

		// Initial render after data loads.
		fetchModels( capability ).then( function ( models ) {
			allModels = models;
			renderList( allModels, currentQuery );
		} );

		// ── Column header sort clicks ───────────────────────────────────
		$colHeaders.on( 'click', '.ab-mp-col-header', function () {
			var col = $( this ).data( 'col' );
			if ( sortState.col === col ) {
				sortState.dir = sortState.dir === 'asc' ? 'desc' : 'asc';
			} else {
				sortState.col = col;
				sortState.dir = 'asc';
			}
			renderList( allModels, currentQuery );
		} );

		// ── Search (debounced) ──────────────────────────────────────────
		var searchTimer = null;
		$search.on( 'input', function () {
			currentQuery = $( this ).val();
			clearTimeout( searchTimer );
			searchTimer = setTimeout( function () {
				renderList( allModels, currentQuery );
			}, 150 );
		} );

		// ── Select a model ──────────────────────────────────────────────
		$list.on( 'click', '.ab-mp-row', function () {
			var id    = $( this ).data( 'model-id' );
			var model = null;
			for ( var i = 0; i < allModels.length; i++ ) {
				if ( allModels[ i ].id === id ) { model = allModels[ i ]; break; }
			}
			if ( ! model ) return;

			$( '#' + fieldId ).val( model.id );
			$trigger.find( '.ab-mp-display-name' ).text( model.name || model.id );

			var isImageModel = model.cost_per_image !== undefined && model.cost_per_image > 0;
			var priceText    = isImageModel
				? '$' + model.cost_per_image.toFixed( 4 ) + '/image'
				: formatPrice( model.input_price_per_m ) + ' / ' + formatPrice( model.output_price_per_m );
			$trigger.find( '.ab-mp-display-price' ).text( priceText );
			closePicker();
		} );

		// ── Close ───────────────────────────────────────────────────────
		function closePicker() {
			$overlay.remove();
		}

		$popup.find( '.ab-mp-close' ).on( 'click', closePicker );
		$overlay.on( 'click', function ( e ) {
			if ( $( e.target ).is( '.ab-mp-overlay' ) ) closePicker();
		} );
		$( document ).on( 'keydown.abModelPicker', function ( e ) {
			if ( e.key === 'Escape' ) {
				closePicker();
				$( document ).off( 'keydown.abModelPicker' );
			}
		} );
	}

	// Bind click on all model picker triggers.
	$( document ).on( 'click', '.ab-mp-trigger', function ( e ) {
		e.preventDefault();
		openPicker( $( this ) );
	} );

} )( jQuery );