'use strict';

var fs = require('fs');
var path = require('path');
var Vinyl = require('vinyl');
var log = require('fancy-log');
var through = require('through2');
var colors = require('ansi-colors');
var PluginError = require('plugin-error');

var PLUGIN_NAME = 'gulp-file-assets';

var ASSETS_RE = /([^'"# ()?]+\.(EXT))\b/ig;

var defExts = [
	'js', 'css', 'html', 'tpl',
	'jpg', 'jpeg', 'png', 'gif', 'svg', 'webp',
	'ttf', 'eot', 'otf', 'woff'
];

function getAvailableExts(includes, excludes) {
	var exts = [];
	for (var i = 0, l = includes.length; i < l; ++i) {
		var ext = includes[i];
		if (excludes.indexOf(ext) < 0) {
			exts.push(ext);
		}
	}
	return exts;
}

function getAbsolutePath(filename) {
	if (!path.isAbsolute(filename)) {
		filename = path.join(process.cwd(), filename);
	}
	return filename;
}

function isLocal(url) {
	return !/^(https?:)?\/\//.test(url);
}

function isIgnored(ignores, filename) {
	for (var i = 0, l = ignores.length; i < l; ++i) {
		var item = ignores[i];
		if (item instanceof RegExp) {
			if (item.test(filename)) {
				return true;
			}
		} else if (item === filename) {
			return true;
		}
	}
	return false;
}

function parseAssets(file, reference, curDepth, opts, push) {
	var depth = opts['depth'];
	var pattern = opts['pattern'];
	var ignores = opts['ignores'];
	var includeSrc = opts['includeSrc'];

	var fileBase = file.base;
	var filePath = file.path;
	var relative = file.relative;
	var contents = file.contents;

	if (isIgnored(ignores, filePath)) {
		return;
	}

	if (reference || includeSrc) {
		log(PLUGIN_NAME + ':', 'Extract', (reference ? colors.green(reference) + ' -> ' : '') + colors.green(relative));
		ignores.push(filePath);
		push(file);
	}

	if (depth > 0 && curDepth >= depth) {
		return;
	}

	var code = contents.toString();
	if (Buffer.from(code).length === contents.length) {
		code.replace(pattern, function ($, url) {
			if (!isLocal(url)) {
				return;
			}
			var files = [
				getAbsolutePath(path.join(fileBase, url)),
				getAbsolutePath(path.join(path.dirname(filePath), url))
			];
			if (files[0] === files[1]) {
				files.pop();
			}
			for (var i = 0, l = files.length; i < l; ++i) {
				var filename = files[i];
				if (fs.existsSync(filename)) {
					var asset = new Vinyl({
						path: filename,
						base: fileBase,
						contents: fs.readFileSync(filename)
					});
					parseAssets(asset, relative, curDepth + 1, opts, push);
				}
			}
		});
	}
}

function fileAssets(opts) {
	opts = opts || {};
	var depth = opts['depth'] || null;
	var exts = getAvailableExts(opts['exts'] || defExts, opts['excludes'] || []);
	var pattern = new RegExp(ASSETS_RE.source.replace('EXT', exts.join('|')), 'ig');
	var includeSrc = opts['includeSrc'] === undefined || opts['includeSrc'];
	var ignores = opts['ignores'];

	if (ignores) {
		ignores = ignores.concat();
		for (var i = 0, l = ignores.length; i < l; ++i) {
			var item = ignores[i];
			if (!(item instanceof RegExp)) {
				ignores[i] = getAbsolutePath(item);
			}
		}
	} else {
		ignores = [];
	}

	return through.obj(function (file, enc, cb) {
		if (file.isNull()) {
			return cb();
		} else if (file.isStream()) {
			cb(new PluginError(PLUGIN_NAME, 'Streaming not supported'));
		} else if (file.isBuffer()) {
			parseAssets(file, null, 0, {
				depth: depth,
				pattern: pattern,
				ignores: ignores,
				includeSrc: includeSrc
			}, this.push.bind(this));
			cb();
		}
	});
}

fileAssets.defExts = defExts;

module.exports = fileAssets;