/**
 * WP Data Optimizer — REST API JavaScript SDK
 *
 * Lightweight client for /wp-json/wpdo/v1/ endpoints.
 * No dependencies required.
 *
 * Usage:
 *   const wpdo = new WpdoClient();
 *
 *   // Fetch listings (Zone A)
 *   const { items, total } = await wpdo.getListings({ hp_price_min: 100, per_page: 20 });
 *
 *   // Single listing (Zone A + Zone C)
 *   const listing = await wpdo.getListing(123);
 *
 *   // View count (Zone B)
 *   const { view_count } = await wpdo.getStats(123);
 *
 *   // Increment view count (Zone B, requires WP REST nonce)
 *   const { view_count: updated } = await wpdo.incrementView(123);
 *
 *   // Iterate all pages
 *   for await (const page of wpdo.paginateListings({ hp_featured: 1 })) {
 *     console.log(page.items);
 *   }
 *
 * @package WP_Data_Optimizer
 */

/* global wpdo_sdk_config */

( function ( global ) {
	'use strict';

	/**
	 * WpdoClient — REST API wrapper for WP Data Optimizer.
	 *
	 * @param {object} [options]
	 * @param {string} [options.baseUrl]   REST base URL (default: auto-detected from wpdo_sdk_config or /wp-json)
	 * @param {string} [options.nonce]     WP REST nonce for authenticated requests
	 * @param {string} [options.postType]  Default post type (default: 'hp_listing')
	 */
	function WpdoClient( options ) {
		options = options || {};

		var config = ( typeof wpdo_sdk_config !== 'undefined' ) ? wpdo_sdk_config : {};

		this._base     = options.baseUrl || config.rest_url || '/wp-json/wpdo/v1';
		this._nonce    = options.nonce || config.nonce || '';
		this._postType = options.postType || config.post_type || 'hp_listing';
	}

	// ── Core fetch ────────────────────────────────────────────────────────────

	/**
	 * Internal GET fetch helper.
	 *
	 * @param  {string} path    Relative path (e.g. '/listings')
	 * @param  {object} params  Query parameters
	 * @return {Promise<{data: *, headers: Headers, status: number}>}
	 */
	WpdoClient.prototype._fetch = function ( path, params ) {
		var url = this._base + path;

		if ( params && Object.keys( params ).length ) {
			var qs = Object.keys( params )
				.filter(
					function ( k ) {
						return params[ k ] !== null && params[ k ] !== undefined && params[ k ] !== ''; }
				)
				.map(
					function ( k ) {
						return encodeURIComponent( k ) + '=' + encodeURIComponent( params[ k ] ); }
				)
				.join( '&' );
			if ( qs ) {
				url += '?' + qs;
			}
		}

		var headers = { 'Content-Type': 'application/json' };
		if ( this._nonce ) {
			headers[ 'X-WP-Nonce' ] = this._nonce;
		}

		return fetch( url, { headers: headers } ).then(
			function ( res ) {
				return res.json().then(
					function ( data ) {
						return { data: data, headers: res.headers, status: res.status };
					}
				);
			}
		);
	};

	/**
	 * Internal POST fetch helper.
	 *
	 * @param  {string} path  Relative path
	 * @param  {object} body  JSON body (optional)
	 * @return {Promise<{data: *, status: number}>}
	 */
	WpdoClient.prototype._post = function ( path, body ) {
		var headers = { 'Content-Type': 'application/json' };
		if ( this._nonce ) {
			headers[ 'X-WP-Nonce' ] = this._nonce;
		}

		return fetch(
			this._base + path,
			{
				method:  'POST',
				headers: headers,
				body:    body ? JSON.stringify( body ) : null,
			}
		).then(
			function ( res ) {
				return res.json().then(
					function ( data ) {
						return { data: data, status: res.status };
					}
				);
			}
		);
	};

	// ── Public API ────────────────────────────────────────────────────────────

	/**
	 * Fetch a page of listings from Zone A.
	 *
	 * @param  {object} [params]
	 * @param  {string} [params.post_type]    Default: configured post type
	 * @param  {number} [params.per_page]     1–100, default 20
	 * @param  {number} [params.page]         Default 1
	 * @param  {string} [params.orderby]      Column name, default 'post_id'
	 * @param  {string} [params.order]        'ASC' | 'DESC', default 'DESC'
	 * @param  {number} [params.*_min]        Numeric range filter (e.g. hp_price_min)
	 * @param  {number} [params.*_max]        Numeric range filter (e.g. hp_price_max)
	 * @param  {*}      [params.*]            Exact match filter (e.g. hp_featured: 1)
	 * @return {Promise<{items: Array, total: number, totalPages: number}>}
	 */
	WpdoClient.prototype.getListings = function ( params ) {
		var merged = Object.assign( { post_type: this._postType }, params || {} );
		return this._fetch( '/listings', merged ).then(
			function ( res ) {
				return {
					items:      res.data,
					total:      parseInt( res.headers.get( 'X-WP-Total' ) || '0', 10 ),
					totalPages: parseInt( res.headers.get( 'X-WP-TotalPages' ) || '0', 10 ),
					status:     res.status,
				};
			}
		);
	};

	/**
	 * Fetch a single listing (Zone A + Zone C merged).
	 *
	 * @param  {number} id  Post ID
	 * @return {Promise<object>}
	 */
	WpdoClient.prototype.getListing = function ( id ) {
		return this._fetch( '/listings/' + id, null ).then(
			function ( res ) {
				return res.data;
			}
		);
	};

	/**
	 * Fetch Zone B view count for a post.
	 *
	 * @param  {number} id  Post ID
	 * @return {Promise<{post_id: number, view_count: number}>}
	 */
	WpdoClient.prototype.getStats = function ( id ) {
		return this._fetch( '/stats/' + id, null ).then(
			function ( res ) {
				return res.data;
			}
		);
	};

	/**
	 * Increment Zone B view count for a post (requires WP REST nonce).
	 *
	 * The nonce must be passed via the `nonce` constructor option or
	 * via `wpdo_sdk_config.nonce` (wp_create_nonce('wp_rest')).
	 *
	 * @param  {number} id  Post ID
	 * @return {Promise<{post_id: number, view_count: number}>}
	 *
	 * Example:
	 *   // Auto-tracks a view when a listing page loads:
	 *   document.addEventListener('DOMContentLoaded', () => {
	 *     const postId = parseInt(document.body.dataset.postId);
	 *     if (postId) wpdo.incrementView(postId);
	 *   });
	 */
	WpdoClient.prototype.incrementView = function ( id ) {
		return this._post( '/listings/' + id + '/view', null ).then(
			function ( res ) {
				return res.data;
			}
		);
	};

	/**
	 * Async generator — iterates every page of listings.
	 *
	 * @param  {object} [params]  Same params as getListings (page is managed internally)
	 * @yields {{items: Array, total: number, page: number, totalPages: number}}
	 *
	 * Example:
	 *   for await (const page of wpdo.paginateListings({ hp_featured: 1 })) {
	 *     page.items.forEach(item => console.log(item));
	 *   }
	 */
	WpdoClient.prototype.paginateListings = async function * ( params ) {
		var page    = 1;
		var total   = Infinity;
		var perPage = ( params && params.per_page ) ? params.per_page : 20;

		while ( ( page - 1 ) * perPage < total ) {
			var merged = Object.assign( {}, params || {}, { page: page } );
			var result = await this.getListings( merged );
			total      = result.total;
			yield { items: result.items, total: total, page: page, totalPages: result.totalPages };
			if ( page >= result.totalPages ) {
				break;
			}
			page++;
		}
	};

	// ── Export ────────────────────────────────────────────────────────────────

	global.WpdoClient = WpdoClient;

	// Auto-instantiate as window.wpdo if config is present.
	if ( typeof wpdo_sdk_config !== 'undefined' ) {
		global.wpdo = new WpdoClient();
	}

}( window ) );