'use strict';

var fs = require('fs');

var assemblerConstructors = {
	readFile : function() {
		return function(file, callback) {
			fs.readFile(file, function(err, data) {
				if (err) {
					callback(err);
				} else {
					callback(null, data);
				}
			});
		};
	},
	readFileMinify : function(options) {
		if (options === undefined) {
			options = {};
		}
		var minify = require('minify');
		return function(file, callback) {
			minify(file, options, function(err, data) {
				if (err) {
					callback(err);
				} else {
					callback(null, data);
				}
			});
		};
	},
	readFileRegex : function(regexData) {
		if (regexData === undefined) {
			// Simple regex which cleans most stuff from js and css.
			regexData = {
					'(\\s\\\|\\|\\s)': '||',    // clean bit-or space
					'(\\s\\\&\\&\\s)': '&&',    // clean bit-and space
					'(if\\s\\(\\s)':   'if(',   // clean if space
					'(for\\s\\(\\s)':  'for(',  // clean for space
					'(\\s*{\\s*)':     '{',     // clean bracket open
					'(^\\s*}\\s*)':    '}\n',   // clean bracket close
					'(^\\s+)':         '',                       // clean up white space
					'(\\{[\\s\\/]+\\/.*)': '{',                  // rm comment on functions
					'(^|\\s\\/\\/.*)': '',                       // rm comment lines
					'(\\/\\*[\\s\\*\\!][\\s\\S]*?\\*\\/)': '',   // rm comment blocks
			};
		}
		return function(file, callback) {
			fs.readFile(file, function(err, data) {
				if (err) {
					callback(err);
				} else {
					data = ''+data;
					var regexList = Object.keys(regexData);
					for (var i = 0; i < regexList.length; i++) {
						var regex = new RegExp(regexList[i],'gm');
						var regexReplace = regexData[regexList[i]];
						data = data.replace(regex,regexReplace);
					}
					callback(null, data);
				}
			});
		};
	},
};

var assemblerEventLog = {
	console : function(logType) {
		if (logType === undefined) {
			throw new Error('no logType');
		}
		return function(logMessage) {
			console.log('node-ff-assets:' + logType + ' ' + logMessage);
		};
	},
	winston: function(logger, logType) {
		if (logger === undefined) {
			throw new Error('no logger');
		}
		if (logType === undefined) {
			throw new Error('no logType');
		}
		return function(logMessage) {
			logger.log('node-ff-assets:'+logType+' '+logMessage);
		};
	},
};

var assemblerEventResult = {
	objectFunction : function(object, functionName, resultKey) {
		if (object === undefined) {
			throw new Error('no object');
		}
		if (functionName === undefined) {
			throw new Error('no functionName');
		}
		return function(resultValue) {
			if (resultKey === undefined) {
				object[functionName](resultValue);
			} else {
				object[functionName](resultKey, resultValue);
			}
		};
	},
	objectAdd : function(object, resultKey) {
		return assemblerEventResult.objectFunction(object, 'add', resultKey);
	},
	objectSet : function(object, resultKey) {
		return assemblerEventResult.objectFunction(object, 'set', resultKey);
	},
	objectPut : function(object, resultKey) {
		return assemblerEventResult.objectFunction(object, 'put', resultKey);
	},
	arrayPush : function(object) {
		return assemblerEventResult.objectFunction(object, 'push');
	},
};

var libAsync = {
	pushLinkSources: function (builder, linkPrefix, fileFolder) {
		return function(callback) {
			fs.readdir(fileFolder, function (err, fileList) {
				if (err) {
					callback(err);
				} else {
					fileList.forEach(function (file) {
						if (file.indexOf('.js') > 0 || file.indexOf('.css') > 0) {
							builder.linkSources.push(linkPrefix+file);
						}
					});
					callback(null,null);
				}
			});
		};
	},
};

var builderAssemblerCreate = {
	readFile: function () {
		return function (assemblerConfig, callback) {
			var AS = require('./asset-assembler');
			callback(null,new AS(assemblerConfig,assemblerConstructors.readFile()));
		};
	},
	readFileMinify: function(options) {
		return function (assemblerConfig, callback) {
			var AS = require('./asset-assembler');
			callback(null,new AS(assemblerConfig,assemblerConstructors.readFileMinify(options)));
		};
	},
	readFileRegex: function(options) {
		return function (assemblerConfig, callback) {
			var AS = require('./asset-assembler');
			callback(null,new AS(assemblerConfig,assemblerConstructors.readFileRegex(options)));
		};
	},
};

var builderEmptyCallback = function () {
	return function (object, callback) {
		if (callback !== undefined) {
			callback();
		}
	};
};

var builderConfigCreate = {
	nop: builderEmptyCallback,
	fromJSON: function (configJSON,type) {
		return function(callback) {
			callback(null,{
				// TODO: add merging 
				linkMapping:  configJSON.linkMapping,
				linkTarget:   configJSON[type].linkTarget,
				linkSources:  configJSON[type].linkSources,
				assetType:    type,
			});
		};
	},
};

module.exports = {
	assembler: {
		constructor :      assemblerConstructors,
		event : {
			log :          assemblerEventLog,
			result :       assemblerEventResult,
		},
	},
	builder: {
		configCreate:      builderConfigCreate,
		configFill:        { nop: builderEmptyCallback },
		assemblerCreate:   builderAssemblerCreate,
		assemblerFill:     { nop: builderEmptyCallback },
	},
	lib: {
		async:             libAsync,
	},
};