var UserInterface = function(terminal) {

	this.terminal = terminal;

	this.view = document.createElement('div');
	this.view.style.whiteSpace = 'pre-wrap';
	this.view.style.wordWrap = 'break-word';
	this.view.style.wordBreak = 'break-all';

	this.code = document.createElement('code');

	this.completion = document.createElement('span');
	this.completion.style.color = '#d09050';

	this.prompt = document.createElement('span');

	this.input = document.createElement('input');
	this.input.type = 'text';
	this.DEFAULT_INPUT_SIZE = this.input.size;

	this.view.appendChild(this.code);
	this.code.appendChild(this.completion);
	this.code.appendChild(this.prompt);
	this.code.appendChild(this.input);

	this.parser = new Parser();

	this.inputHistory = [];
	this.inputHistoryIndex = this.inputHistory.length;

	var self = this;

	this.splitPath = function(path) {
		var slash = path.lastIndexOf('/');
		if (slash == -1) {
			return [ '', path ];
		} else if (path.length > 1 && slash == path.length - 1) {
			return [ path, '' ];
		} else if (slash == 0) {
			return [ '/', path.substr(1) ];
		} else {
			return [ path.substr(0, slash), path.substr(slash + 1) ];
		}
	};

	this.headCompletionCallback = function(packet, args) {
		if (packet.opcode == 'StringList') {
			self.parser.setLine(self.input.value);
			self.parser.parse();
			var elements = self.parser.tokens;
			var originalElements = self.parser.originalTokens;

			var length = 0;
			var index;
			if (originalElements.length < 1) {
				index = -1;
			} else {
				for (index = 0; index < originalElements.length; index++) {
					if (length + originalElements[index].length >= self.input.selectionStart) {
						break;
					}
					length += originalElements[index].length;
				}
			}

			var word = '';
			if (index >= 0 && index < elements.length) {
				word = elements[index];
			}

			var list = args.concat(self.createCompletionList(packet.list, word));

			if (list.length < 2) {
				if (index >= 0) {
					if (index < 1) {
						originalElements[index] = list[0];
					} else {
						originalElements[index] = ' ' + list[0];
					}
					self.input.value = originalElements.join('') + ' ';
					self.completion.textContent = '';
				}
			} else {
				self.completion.textContent = list.join(' ') + '\n';
				self.scrollToBottom();
			}
		} else {
			self.println(packet.opcode);
		}
	};

	this.completionCallback = function(packet, args) {
		var list = [];
		var i;
		if (packet.opcode == 'FileException') {
			if (packet.type == 'IS_FILE') {
				list.push({ name: args[1], type: 'FILE' });
				return;
			} else {
				self.completion.textContent = packet.type;
				return;
			}
		} else if (packet.opcode == 'FileList') {
			for (i = 0; i < packet.list.length; i++) {
				if (packet.list[i].name.indexOf(args[1]) == 0) {
					list.push(packet.list[i]);
				}
			}
		}

		if (list.length < 1) {
			self.completion.textContent = '';
		} else if (list.length < 2) {
			self.parser.setLine(self.input.value);
			self.parser.parse();
			var elements = self.parser.tokens;
			var originalElements = self.parser.originalTokens;

			var length = 0;
			var index;
			if (originalElements.length < 1) {
				index = -1;
			} else {
				for (index = 0; index < originalElements.length; index++) {
					if (length + originalElements[index].length >= self.input.selectionStart) {
						break;
					}
					length += originalElements[index].length;
				}
			}

			if (index >= 0) {
				var filename;
				if (args[0].length < 1) {
					filename = list[0].name;
				} else {
					if (args[0] == '/') {
						filename = '/' + list[0].name;
					} else {
						if (args[0].charAt(args[0].length - 1) == '/') {
							filename = args[0] + list[0].name;
						} else {
							filename = args[0] + '/' + list[0].name;
						}
					}
				}
				if (filename.indexOf(' ') >= 0) {
					filename = '"' + filename + '"';
				}
				originalElements[index] = ' ' + filename;
				if (list[0].type == 'DIRECTORY') {
					self.input.value = originalElements.join('') + '/';
				} else {
					self.input.value = originalElements.join('') + ' ';
				}
				self.completion.textContent = '';
				if (self.input.value.length < self.DEFAULT_INPUT_SIZE) {
					self.input.size = self.DEFAULT_INPUT_SIZE;
				} else {
					self.input.size = self.input.value.length;
				}
			}
		} else {
			var names = [];
			for (i = 0; i < list.length; i++) {
				names.push(list[i].name);
			}
			self.completion.textContent = names.join(' ') + '\n';
			self.scrollToBottom();
		}
	};

	this.handleInput = function(e) {
		if (e.keyCode == 13) { // ENTER
			var value = self.input.value;
			self.input.value = '';
			self.addHistory(value);
			self.inputHistoryIndex = self.inputHistory.length;
			self.completion.textContent = '';
		} else if (e.keyCode == 9) { // TAB
			e.preventDefault();

			self.parser.setLine(self.input.value);
			self.parser.parse();
			var elements = self.parser.tokens;
			var originalElements = self.parser.originalTokens;

			var length = 0;
			var index;
			if (originalElements.length < 1) {
				index = -1;
			} else {
				for (index = 0; index < originalElements.length; index++) {
					if (length + originalElements[index].length >= self.input.selectionStart) {
						break;
					}
					length += originalElements[index].length;
				}
			}
			var word = '';
			if (index >= 0 && index < elements.length) {
				word = elements[index];
			}

			if (index < 1) {
				var list = self.createCompletionList(self.completionListHead, word);
				self.terminal.api.commandList(self.headCompletionCallback, list);
			} else {
				var sp = self.splitPath(word);
				var absolutePath = self.terminal.session.toAbsolutePath(sp[0]);
				self.terminal.fileAPI.list(self.completionCallback, sp, absolutePath);
			}
		} else if (e.keyCode == 38) { // UP
			if (self.inputHistoryIndex < 0) {
				self.input.value = '';
			} else {
				self.inputHistoryIndex--;
				if (self.inputHistoryIndex < 0) {
					self.input.value = '';
				} else {
					self.input.value = self.inputHistory[self.inputHistoryIndex];
				}
			}
		} else if (e.keyCode == 40) { // DOWN
			if (self.inputHistoryIndex >= self.inputHistory.length) {
				self.input.value = '';
			} else {
				self.inputHistoryIndex++;
				if (self.inputHistoryIndex >= self.inputHistory.length) {
					self.input.value = '';
				} else {
					self.input.value = self.inputHistory[self.inputHistoryIndex];
				}
			}
		}
		if (self.input.value.length < self.DEFAULT_INPUT_SIZE) {
			self.input.size = self.DEFAULT_INPUT_SIZE;
		} else {
			self.input.size = self.input.value.length;
		}
		if (e.keyCode == 13) { // ENTER
			self.input.onkeydown = null;
			self.inputCallback(value);
		}
	};

	this.handleTemporalInput = function(e) {
		if (e.keyCode == 13) { // ENTER
			var value = self.input.value;
			self.input.value = '';
		}
		if (self.input.value.length < self.DEFAULT_INPUT_SIZE) {
			self.input.size = self.DEFAULT_INPUT_SIZE;
		} else {
			self.input.size = self.input.value.length;
		}
		if (e.keyCode == 13) { // ENTER
			self.input.onkeydown = null;
			self.temporalInputCallback(value);
		}
	};

	this.login2 = function(line) {
		self.account = line;
		self.print(self.prompt.textContent);
		self.println(line);
		self.temporalInputCallback = self.login3;
		self.prompt.textContent = 'Password: ';
		self.input.type = 'password';
		self.input.onkeydown = self.handleTemporalInput;
	};

	this.login3 = function(line) {
		self.println(self.prompt.textContent);
		self.prompt.textContent = self.terminal.promptString;
		self.temporalInputCallback = null;
		self.input.type = 'text';
		var account = self.account;
		self.account = null;
		self.inputCallback(account, line);
	};

};

UserInterface.prototype.addHistory = function(s) {
	if (s.length < 1) {
		return;
	}
	for (var i = this.inputHistory.length - 1; i >= 0; i--) {
		if (this.inputHistory[i] == s) {
			this.inputHistory.splice(i, 1);
			break;
		}
	}
	this.inputHistory.push(s);
};

UserInterface.prototype.createCompletionList = function(list, word) {
	var result = [];
	for (var i = 0; i < list.length; i++) {
		if (list[i].indexOf(word) == 0) {
			result.push(list[i]);
		}
	}
	return result;
};

UserInterface.prototype.scrollToBottom = function() {
	window.scrollTo(0, document.body.scrollHeight);
};

UserInterface.prototype.clear = function() {
	while (this.code.firstChild != this.completion) {
		this.code.removeChild(this.code.firstChild);
	}
};

UserInterface.prototype.print = function(s, color, background) {
	var output = document.createElement('span');
	output.textContent = s;
	output.style.color = color;
	output.style.background = background;
	this.code.insertBefore(output, this.completion);
	this.scrollToBottom();
};

UserInterface.prototype.println = function(s, color, background) {
	this.print(s + '\n', color, background);
};

UserInterface.prototype.append = function(node) {
	this.code.insertBefore(node, this.prompt);
	this.scrollToBottom();
};

UserInterface.prototype.readLine = function(callback, headList) {
	this.inputCallback = callback;
	this.completionListHead = headList;
	this.input.onkeydown = this.handleInput;
	this.input.focus();
};

UserInterface.prototype.login = function(callback) {
	this.terminal.command.inputCallback = null;
	this.inputCallback = callback;
	this.temporalInputCallback = this.login2;
	this.prompt.textContent = 'Account: ';
	this.input.onkeydown = this.handleTemporalInput;
	this.input.focus();
};