/**
 * Created by robert on 9/17/15.
 */

(function() {
    var problems,//this will the actual (sub)state machine
        stateNameTag = 'stateName';

    //get the divs which are the main elements being change on transitions between states in the sub-state machine
    var divs = {};
    divs['description'] = $('#description_outer_div');//$('div.col-lg-3.col-md-6.col-sm-12:has(#description)');
    divs['code'] = $('#code_editor_outer_div');//$('div.col-lg-3.col-md-6.col-sm-12:has(#code_editor)');
    divs['console'] = $('#console_outer_div');//$('div.col-lg-3.col-md-6.col-sm-12:has(#console)');
    divs['info'] = $('#info_outer_div');//$('div.col-lg-3.col-md-6.col-sm-12:has(#info)');

    //these tags connect the div to their respective state in the sub-state machine
    divs['description'].data(stateNameTag, 'description');
    divs['code'].data(stateNameTag, 'code');
    divs['console'].data(stateNameTag, 'console');
    divs['info'].data(stateNameTag, 'info');

    var transitionEventName = 'mousedown',//event name of the event which will trigger the transition between these substates - the most common transition at least (there are some corner cases on the hint and test buttons -> see the code below)
        /**
         * the general function which should be called on the mousedown event to trigger the transition between states
         */
        mouseDownEventFunction = function () {
            problems.transition($(this).data(stateNameTag));
        },
        /**
         * removes the above function from the divs
         */
        removeListenersFromDivs = function () {
            $.each(divs, function (i, value) {
                value.off(transitionEventName, mouseDownEventFunction);
            });
        },
        /**
         * removes the 'block' class from all divs we need to change when we change the current state
         */
        removeBlockClassesFromDivs = function () {
            $.each(divs, function (i, value) {
                value.removeClass('block');
            });
        },
        /**
         * removes all those special classes from the divs, which are set when a new state is entered and it also adds the 'block' class back
         */
        removeChangedClassesFromDivs = function () {
            $.each(divs, function (i, value) {
                value.removeClass('block-focus block-less-width block-less-height block-less-everything').addClass('block');//these class names were chosen for the view where the screen is partitioned in 4 quarters (2 by 2)
            });
        },
        /**
         *
         * @param current the key of the state ('description','code','hint','console'), which is currently active, because it must not have a transition set
         */
        setTransitionsBetweenDivs = function (current) {
            $.each(divs, function (key, value) {
                if (current !== key) value.on(transitionEventName, mouseDownEventFunction);
            });
        },
        /**
         *
         * @param divsWithClasses a object where we have the keys of the divs object paired with the class name we want to assign to them e.g. :
         *          {
                        'description': 'block-focus',
                        'code': 'block-less-width',
                        'console': 'block-less-height',
                        'info': 'block-less-everything'
                    }
         */
        addClassesToDivs = function (divsWithClasses) {
            $.each(divsWithClasses, function (divName, className) {
                divs[divName].addClass(className);
            });
        },
        /**
         * the buttons (hint and test) will have to 'eat' the mousedown event to prevent some weird transitions.
         * Because a click on them won't trigger the transition to the code part, but will transition to the hints part.
         *
         * @param event
         */
        mouseDownEventIgnoreFun = function(event){
            event.stopPropagation();
        }
        /**
         * The transition from the buttons to the hints screen will be triggered with this function
         */
        clickListenerTransitionFun = function(){
            problems.transition(divs['info'].data(stateNameTag));
        },
        /**
         * add the above function to the buttons
         */
        addClickListenerTranstions  = function(){
            $('#btn_code_hint').on('click',clickListenerTransitionFun);
            $('#btn_code_test').on('click',clickListenerTransitionFun);

            $('#btn_code_hint').on(transitionEventName,mouseDownEventIgnoreFun);
            $('#btn_code_test').on(transitionEventName,mouseDownEventIgnoreFun);
        },
        /**
         * and a function to remove it
         */
        removeClickListenerTransition = function(){
            $('#btn_code_hint').off('click',clickListenerTransitionFun);
            $('#btn_code_test').off('click',clickListenerTransitionFun);

            $('#btn_code_hint').off(transitionEventName,mouseDownEventIgnoreFun);
            $('#btn_code_test').off(transitionEventName,mouseDownEventIgnoreFun);
        },
        substates = {
            'description': {
                'enter': function () {
                    removeBlockClassesFromDivs();
                    addClassesToDivs({
                        'description': 'block-focus',
                        'code': 'block-less-width',
                        'console': 'block-less-height',
                        'info': 'block-less-everything'
                    });
                    setTransitionsBetweenDivs('description');

                    //and set up the buttons
                    addClickListenerTranstions();
                },
                'exit': function () {
                    removeChangedClassesFromDivs();
                    removeListenersFromDivs();
                    removeClickListenerTransition();
                }
            },
            'code': {
                'enter': function () {
                    removeBlockClassesFromDivs();
                    addClassesToDivs({
                        'description': 'block-less-width',
                        'code': 'block-focus',
                        'console': 'block-less-everything',
                        'info': 'block-less-height'
                    });
                    setTransitionsBetweenDivs('code');

                    //and set up the buttons
                    addClickListenerTranstions();
                },
                'exit': function () {
                    removeChangedClassesFromDivs();
                    removeListenersFromDivs();
                    removeClickListenerTransition();
                }
            },
            'info': {
                'enter': function () {
                    removeBlockClassesFromDivs();
                    addClassesToDivs({
                        'description': 'block-less-everything',
                        'code': 'block-less-height',
                        'console': 'block-less-width',
                        'info': 'block-focus'
                    });
                    setTransitionsBetweenDivs('info');

                    //and set up the buttons
                    addClickListenerTranstions();
                },
                'exit': function () {
                    removeChangedClassesFromDivs();
                    removeListenersFromDivs();
                    removeClickListenerTransition();
                }
            },
            'console': {
                'enter': function () {
                    removeBlockClassesFromDivs();
                    addClassesToDivs({
                        'description': 'block-less-height',
                        'code': 'block-less-everything',
                        'console': 'block-focus',
                        'info': 'block-less-width'
                    });
                    setTransitionsBetweenDivs('console');

                    //and set up the buttons
                    addClickListenerTranstions();
                },
                'exit': function () {
                    removeChangedClassesFromDivs();
                    removeListenersFromDivs();
                    removeClickListenerTransition();
                }
            }
        };
    var prologHandler;//created when we enter the prolog state and destroyed once we leave it
    codeq.globalStateMachine.register('prolog', {
        'enter': function (data) {
            $('#disabled').css('display', '');
            $('#screen_prolog').css('display', '');//we have to show the screen now so the code editor shopws its initial values correctly
            prologHandler = createPrologHandler(data.data)//codeq.createProgrammingLanguageHandler('prolog',data.data,codeq.makePrologTerminalHandler);
            problems = codeq.makeStateMachine(substates);
            problems.transition(divs['description'].data(stateNameTag));
            Q.delay(100).then(function(){
                $('div.col-lg-3.col-md-6.col-sm-12').addClass('transition');//for smooth animations - need to be delayed, because otherwise we get some weird "animations" while the page is loading
            }).done();

            $('#disabled').css('display', 'none');
        },
        'exit': function () {
            $('#screen_prolog').css('display', 'none');
            $('div.col-lg-3.col-md-6.col-sm-12').removeClass('transition');
            prologHandler.destroy();
            problems.destroy();
        }
    });

    // a constant
    var firstCharacterPos = {'line': 0, 'ch': 0};

    var makePrologTerminalHandler = function (jqConsole, editor, problem_id, activityHandler) {
        var promptMode = true, // default: query composition; alternative: query result browsing
            terminal = codeq.makeConsole(jqConsole, {
                'greeting': 'CodeQ Prolog terminal proxy'
            }),
            tcs = function terminalCommandSuccess (data) {
                var t, lines, i;
                if (data.code === 0) {
                    t = data.terminal;
                    terminal.append(t.messages.join('\n'), 'output');
                    promptMode = !t.have_more;
                }
                else {
                    terminal.append(data.message, 'error');
                    promptMode = true;
                }
                if (promptMode) {
                    terminal.setLineBuffered();
                    terminal.append('.\n?- ', 'output');
                }
            },
            tcf = function terminalCommandFailed (error) {
                promptMode = true;
                terminal.setLineBuffered();
                terminal.append(error + '\n', 'error');
                terminal.append('?- ', 'output');
            };

        terminal.onKeypress = function (c) {
            if (promptMode) return c; // query composition: return the character unchanged
            switch (c) {
                case ' ':
                case ';':
                case '\n':
                    return ';'; // show next answer on space, semicolon or enter
                default:
                    return '.'; // everything else: stop searching for answers
            }
        };

        terminal.onInput = function (command) {
            if (promptMode) {
                promptMode = false;
                terminal.setNotBuffered();
                return codeq.comms.sendQuery({
                    'problem_id': problem_id,
                    'step': 'run',
                    'program': editor.getDoc().getValue(),
                    'query': command,
                    'trace': activityHandler.addAndPurge({'typ': 'slv', 'qry': command})
                }, problem_id).then(tcs, tcf);
            }
            else {
                terminal.append('\n', 'input');
                if (command == ';') {
                    // show next answer
                    return codeq.comms.sendQuery({
                        'problem_id': problem_id,
                        'step': 'next',
                        'trace': activityHandler.addAndPurge({'typ': 'nxt'})
                    }, problem_id).then(tcs, tcf);
                }
                else {
                    // stop searching for answers
                    return codeq.comms.sendQuery({
                        'problem_id': problem_id,
                        'step': 'end',
                        'trace': activityHandler.addAndPurge({'typ': 'stp'})
                    }, problem_id).then(tcs, tcf);
                }

            }
        };

        terminal.leftmostCol = 3;
        terminal.append('?- ', 'output');

        return terminal;
    };

    var makeActivityHandler = function (editor, problem_id) {
        var lastActivityMillis = Date.now(),
            deltaActivityMillis = function deltaActivityMillisFunc () {
                var now = Date.now(),
                    dt = now - lastActivityMillis;
                lastActivityMillis = now;
                return dt;
            },
            queue = [],
            ts = null,
            timer = function () {
                var promise;
                ts = null;
                if (queue.length === 0) return Q(true);
                promise = codeq.comms.sendActivity(queue, editor.getDoc().getValue(), problem_id);
                queue.length = 0;
                return promise;
            },
            flush = function () {
                clearTimeout(ts);
                return timer();
            };

        return {
            'queueTrace': function (trace) {
                trace['dt'] = deltaActivityMillis();
                queue.push(trace);
                if (ts === null) ts = setTimeout(timer, 10000); // flush every 10 seconds
                return this;
            },
            'flush': flush,
            'addAndPurge': function (trace) {
                var accumulatedTrace = queue;
                queue = [];
                trace['dt'] = deltaActivityMillis();
                accumulatedTrace.push(trace);
                if (ts !== null) {
                    clearTimeout(ts);
                    ts = null;
                }
                return accumulatedTrace;
            }
        };
    };

    /**
     * Creates a new handler for the given Prolog assignment definition.
     *
     * @param {PrologTaskDef} info
     * @returns {{destroy: Function, processServerHints: Function}}
     */
    createPrologHandler = function (info) {
        var problem = info.problem,
            jqDescription = $('#description'),
            jqEditor = $('#code_editor'),
            jqConsole = $('#console'),
            jqHints = $('#info'),
            editor = CodeMirror(jqEditor[0], { cursorHeight: 0.85, lineNumbers: true, matchBrackets: true }),
            activityHandler = makeActivityHandler(editor, problem.id),
            terminal = makePrologTerminalHandler(jqConsole, editor, problem.id, activityHandler),
            hinter = codeq.makeHinter(jqHints, jqEditor, editor, problem.hint);

        editor.setValue(info.solution);
        $('#title').text(problem.slug);
        jqDescription.html(problem.description);

        editor.on('change', function (instance, changeObj) {
            var doc = editor.getDoc(),
                pos = codeq.codePointCount(doc.getRange(firstCharacterPos, changeObj.from));

            if (changeObj.removed) {
                activityHandler.queueTrace({'typ': 'rm', 'off': pos, 'len': codeq.codePointCount(changeObj.removed)});
            }

            if (changeObj.text) {
                activityHandler.queueTrace({'typ': 'ins', 'off': pos, 'txt': changeObj.text});
            }
        });

        $('#btn_code_hint').on('click', function () {
            terminal.append('hint.\n', 'input');
            terminal.inputDisable();
            var doc = editor.getDoc();
            codeq.comms.sendHint({
                'language': 'prolog',
                'program': editor.getDoc().getValue(),
                'problem_id': problem.id
            })
                .then(
                function hintSuccess(data) {
                    if (data.code === 0)
                        hinter.handle(data.hints);
                    else
                        terminal.append(data.message + '\n', 'error');
                },
                function hintFailed (error) {
                    terminal.append(error + '\n', 'error');
                }
            )
                .fin(function () {
                    terminal.inputEnable();
                    terminal.append('?- ', 'output');
                })
                .done();
        });
        $('#btn_code_test').on('click', function () {
            terminal.append('test.\n', 'input');
            terminal.inputDisable();
            var doc = editor.getDoc();
            codeq.comms.sendTest({
                'language': 'prolog',
                'program': editor.getDoc().getValue(),
                'problem_id': problem.id
            })
                .then(
                function testSuccess(data) {
                    if (data.code === 0)
                        hinter.handle(data.hints);
                    else
                        terminal.append(data.message + '\n', 'error');
                },
                function testFailed (error) {
                    terminal.append(error + '\n', 'error');
                }
            )
                .fin(function () {
                    terminal.inputEnable();
                    terminal.append('?- ', 'output');
                })
                .done();
        });

        return {
            destroy: function () {
                $('#btn_code_hint').off('click');
                $('#btn_code_test').off('click');
                editor.off('change');
                hinter.destroy();
                terminal.destroy();
                jqDescription.empty();
                jqEditor.empty(); // TODO: perhaps you do not want to "free" the editor, just empty it
                jqConsole.empty(); // TODO: the same with the console
                jqDescription = null;
                jqEditor = null;
                jqConsole = null;
                jqHints = null;
            }
        };
    };
})();