/*
metalsmith-meta
adds further meta information to metalsmith files:
	root						- the absolute or relative website root folder
	layout					- sets from default from collection
	isPage					- is an index page
	mainCollection	- the primary collection name
	navmain					- array of main navigation pages
	navsub					- array of secondary navigation pages
*/
module.exports = function() {

	'use strict';

	return function(files, metalsmith, done) {

		var
			meta = metalsmith.metadata(),
			file, f, page, p, c, thisCol, layout;

		for (f in files) {

			file = files[f];

			// calculate root
			file.root = file.root || meta.rootpath || (file.path ? '../'.repeat(file.path.split('/').length) : '');

			// get first non-page collection
			file.mainCollection = null;
			file.isPage = false;
			c = 0;
			while (c < file.collection.length) {
				if (file.collection[c] == 'page') {
					file.isPage = true;
				}
				else {
					file.mainCollection = file.mainCollection || file.collection[c];
				}
				c++;
			}

			// main navigation
			file.navmain = [];

			for (p = 0; p < meta.collections.page.length; p++) {

				page = meta.collections.page[p];
				if (!p || page.path != meta.collections.page[p-1].path) {
					file.navmain.push({
						title:				page.title || 'Home',
						description:	page.description || '',
						image:				file.root + page.image || '',
						path:					file.root + page.path + (page.path ? '/' : ''),
						dateFormat:		page.dateFormat,
						active:				page.path == file.path || page.collection.indexOf(file.mainCollection) >= 0
					});
				}

			}

			if (file.mainCollection) {

				// get collection metadata
				thisCol = meta.collections[file.mainCollection];

				// layout from page, collection, default
				layout = file.layout || (thisCol.metadata && thisCol.metadata.layout) || null;
				if (layout) file.layout = layout;

				// secondary navigation
				file.navsub = [];
				for (p = 0; p < thisCol.length; p++) {

					page = thisCol[p];
					if (page.collection.indexOf('page') < 0 && (!p || page.path != thisCol[p-1].path)) {
						file.navsub.push({
							title:				page.title || 'Home',
							description:	page.description || '',
							image:				file.root + page.image || '',
							path:					file.root + page.path + (page.path ? '/' : ''),
							dateFormat:		page.dateFormat,
							active:				page.path == file.path
						});
					}

				}

			}

		}

		done();

	};

};