// This plugin to Meteor uses the linter plugin api to package up all the templates indexed by name into a single file saved in the /private folder in the project.
// The file is intended to be used to service search engine requests for static html by utilizing server side rendering of the templates.
// Meteor packages up all the content not in /private or /public, so simply accessing the templates at runtime on the server does not appear to be an option.

const fs = Npm.require('fs');
const path = Npm.require('path');

//Disabled linter for now.  Supposedly Google at least can manage SEO without server side rendering.
//Plugin.registerLinter({
//	extensions: ["html"]
//	//filenames: [".jshintrc"]
//}, () => new S3);


class S3 {
	constructor() {
		this.templateStart = /<template\s+name\s*=\s*(['"])\b(.*?)\1\s*>/;
		this.templateEnd = /<\/\s*template\s*>\s*/;
	}
	extractTemplate(html, map) {
		try {
			let result = html.match(this.templateStart);
			
			if(result != null) {
				let name = result[2];
				
				html = html.substring(result.index + result[0].length);
				result = html.match(this.templateEnd);
				//console.log("Matching: \n" + html);
				//console.log("\n" + result);
				
				if(result != null) {
					let contents = html.substring(0, result.index);
					html = html.substring(result.index + result[0].length);
					
					//Save the template contents indexed by its name.
					//TODO: Warn if we overwrite any template names???  Should never happen unless the developer made an error in naming.
					map[name] = contents;
					//console.log("Found template: " + name);
					//console.log(contents);
				}
				else html = null;
			}
			else html = null;
		} catch(err) {
			console.log(err);
			html = null;
		}
		
		return html;
	}
	processFilesForPackage(files, options) {
		try {
			let map = {};
			//let fileNames = [];
			let _this = this;
			let originalContents = fs.readFileSync('private/template-index', {encoding: 'utf8', flag: 'r'});
			let counter = 0;
			
			//Extract all templates for every file processed (all HTML files).
			files.forEach((file) => {
				if(file._source.relPath.startsWith("imports/")) {   /// && file._source.relPath === "imports/ui/Test.html"
					let html = file.getContentsAsString();
					
					while(html != null) {
						//Will return null if no more templates are to be found.
						html = this.extractTemplate(html, map);
					}
				}
			});
			
			
			//Returns a 16 character hex hash that is zero padded.
			let hashString = (str)=> {
				let hash = 0;
				
				if(str.length === 0) return hash;
				
				for(let i = 0; i < str.length; i++) {
					let chr = str.charCodeAt(i);
					hash  = ((hash << 5) - hash) + chr;
					hash |= 0; // Convert to 32bit integer
				}
				
				return ("0000000000000000" + hash.toString(16)).substr(-16);
			};
			
			let output = JSON.stringify(map);
			//console.log("Out: " + output);
			let hash = hashString(output);
			//console.log("Hash: " + hash);
			let originalHash = hashString(originalContents);
			
			//console.log(originalHash);
			
			if(originalHash !== hash) {
				//console.log("Hash does not match!");
				//Write the mapping to a 'template-index' file in the private folder.
				fs.writeFile('private/template-index', output);
			}
			else {
				//console.log("Hash matches..");
			}
		} catch(err) {
			console.log(err);
		}
	}
}