/*
	MIT License http://www.opensource.org/licenses/mit-license.php
	Author Tobias Koppers @sokra
*/
function ProgressPlugin(handler) {
	this.handler = handler;
}
module.exports = ProgressPlugin;

ProgressPlugin.prototype.apply = function(compiler) {
	var handler = this.handler;
	if(compiler.compilers) {
		var states = new Array(compiler.compilers.length);
		compiler.compilers.forEach(function(compiler, idx) {
			compiler.apply(new ProgressPlugin(function(p, msg) {
				states[idx] = [p, msg];
				handler(states.map(function(state) {
					return state && state[0] || 0;
				}).reduce(function(a, b) {
					return a + b;
				}) / states.length, states.map(function(state) {
					return state && state[1];
				}).filter(Boolean).join(" | "));
			}));
		});
	} else {
		var lastModulesCount = 0;
		var moduleCount = 1;
		var doneModules = 0;
		function update() {
			handler(0.1 + (doneModules / Math.max(lastModulesCount, moduleCount)) * 0.6, doneModules + "/" + moduleCount + " build modules");
		}
		compiler.plugin("compilation", function(compilation) {
			if(compilation.compiler.isChild()) return;
			lastModulesCount = moduleCount;
			moduleCount = 0;
			doneModules = 0;
			handler(0, "compile");
			compilation.plugin("build-module", function(module) {
				moduleCount++;
				update();
			});
			compilation.plugin("succeed-module", function(module) {
				doneModules++;
				update();
			});
			compilation.plugin("optimize", function() {
				handler(0.73, "optimize");
			});
			compilation.plugin("before-hash", function() {
				handler(0.75, "hashing");
			});
			compilation.plugin("before-chunk-assets", function() {
				handler(0.76, "create chunk assets");
			});
			compilation.plugin("additional-chunk-assets", function() {
				handler(0.78, "additional chunk assets");
			});
			compilation.plugin("optimize-chunk-assets", function(chunks, callback) {
				handler(0.8, "optimize chunk assets");
				callback();
			});
			compilation.plugin("optimize-assets", function(assets, callback) {
				handler(0.9, "optimize assets");
				callback();
			});
		});
		compiler.plugin("emit", function(compilation, callback) {
			handler(0.95, "emit");
			callback();
		});
		compiler.plugin("done", function(stats) {
			handler(1, "");
		});
	}
};