/**
 * Created by robert on 9/17/15.
 *
 * The python state of the state machine. When it is entered it'll prepare the console and code editor and load a sub-state machine which represents the 4 different parts fo the screen.
 *
 * Currentyl it is mostly a copy of the prolog state (the exception is of course the makePythonTerminalHandler instead of makePrologTerminalHandler)
 */

(function() {
    var subScreens, //this will be the actual (sub)state machine
        stateNameTag = 'stateName', //a tag for data which is added to some html elements
        jqScreen = $('#screen_python'), // the screen container element
        //quadrants
        jqDescription = jqScreen.find('.block1'),
        jqCode = jqScreen.find('.block2'),
        jqConsole = jqScreen.find('.block3'),
        jqInfo = jqScreen.find('.block4'),
        jqAllQuadrants = jqDescription.add(jqCode).add(jqConsole).add(jqInfo), // all the quadrants
        // buttons
        jqBtnPlan = jqScreen.find('.btn-plan'),
        jqBtnHint = jqScreen.find('.btn-hint'),
        jqBtnTest = jqScreen.find('.btn-test'),
        jqBtnRun = jqScreen.find('.btn-run'),
        jqBtnStop = jqScreen.find('.btn-stop'),
        jqInfoButtons = jqBtnPlan.add(jqBtnHint).add(jqBtnTest), // all info-focusing buttons
        jqAllButtons = jqInfoButtons.add(jqBtnRun).add(jqBtnStop), // all buttons
        // misc
        currentSubState = null,
        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)
        substates = {
            'description': {
                'enter': function () {
                    currentSubState = 'block1';
                    jqScreen.addClass(currentSubState);
                },
                'exit': function () {
                    jqScreen.removeClass(currentSubState);
                    currentSubState = null;
                }
            },
            'code': {
                'enter': function () {
                    currentSubState = 'block2';
                    jqScreen.addClass(currentSubState);
                },
                'exit': function () {
                    jqScreen.removeClass(currentSubState);
                    currentSubState = null;
                }
            },
            'info': {
                'enter': function () {
                    currentSubState = 'block4';
                    jqScreen.addClass(currentSubState);
                },
                'exit': function () {
                    jqScreen.removeClass(currentSubState);
                    currentSubState = null;
                }
            },
            'console': {
                'enter': function () {
                    currentSubState = 'block3';
                    jqScreen.addClass(currentSubState);
                },
                'exit': function () {
                    jqScreen.removeClass(currentSubState);
                    currentSubState = null;
                }
            }
        };
    var pythonHandler; //created when we enter the python state and destroyed once we leave it
    codeq.globalStateMachine.register('python', {
        'enter': function (problemDef, commonHints, currentSolution) {
            $('#navigation-language').css('display', '');
            $('#navigation-problem').css('display', '');
            $("#navigation-python").addClass("active");
            $('#navigation-python').css('display', '');

            jqScreen.css('display', '');//we have to show the screen now so the code editor shows its initial values correctly
            pythonHandler = createPythonHandler(problemDef, commonHints, currentSolution);
            subScreens = codeq.makeStateMachine(substates);
            subScreens.transition(jqDescription.data(stateNameTag));
/*            Q.delay(100).then(function(){
             jqAllQuadrants.addClass('transition');//for smooth animations - need to be delayed, because otherwise we get some weird "animations" while the page is loading
             }).done();*/
            jqInfoButtons.on(transitionEventName, function (event) {
                subScreens.transition('info'); // set focus on the hints quadrant
                event.stopPropagation(); // don't allow the event to go on and trigger further transition
            });
            jqBtnRun.on(transitionEventName, function (event) {
                subScreens.transition('console'); // set focus on the hints quadrant
                event.stopPropagation(); // don't allow the event to go on and trigger further transition
            });

            jqAllQuadrants.on(transitionEventName, function () {
                subScreens.transition($(this).data(stateNameTag));
            });
        },
        'exit': function () {
            jqAllButtons.off(); // unregister all event handlers
            jqAllQuadrants.off();
            jqScreen.css('display', 'none');
//            jqAllQuadrants.removeClass('transition');
            pythonHandler.destroy();
            pythonHandler = null;
            subScreens.destroy();
            subScreens = null;
            jqScreen.addClass('block1');

            $('#navigation-language').css('display', 'none');
            $('#navigation-problem').css('display', 'none');
            $("#navigation-python").removeClass("active");
            $('#navigation-python').css('display', 'none');
        }
    });

    jqDescription.data(stateNameTag, 'description');
    jqCode.data(stateNameTag, 'code');
    jqConsole.data(stateNameTag, 'console');
    jqInfo.data(stateNameTag, 'info');

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

    var makePythonTerminalHandler = function (jqConsole, editor, problem_id, activityHandler) {
        var terminal = codeq.makeConsole(jqConsole, {
                'greeting': 'CodeQ Python terminal proxy',
                'autoHistory': true
            }),
            tcs = function terminalCommandSuccess (data) {
                if (data.code !== 0) {
                    terminal.append(data.message, 'error');
                }
            },
            tcf = function terminalCommandFailed (error) {
                terminal.append(error + '\n', 'error');
            };

        terminal.onInput = function (text) {
            terminal.leftmostCol = 0;
            return codeq.comms.sendPythonPush({
                'text': text + '\n'
            }).then(tcs, tcf);
        };

        codeq.comms.on('terminal_output', function (data) {
            var text = data.text,
                lines = text.split('\n');
            terminal.append(text, 'output');
            terminal.leftmostCol = lines[lines.length-1].length;
        });

        terminal.leftmostCol = 1;

        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;
            }
        };
    };

    codeq.on('init', function (args) {
        codeq.tr.registerDictionary('python', codeq.tr.emptyDictionary); // to make the translator happy, when this screen is not active
    });

    /**
     * Creates a new handler for the given Prolog assignment definition.
     *
     * @param {PrologTaskDef} info
     * @returns {{destroy: Function, processServerHints: Function}}
     */
    var createPythonHandler = function (problemDef, commonHints, currentSolution) {
        var //problem = info.problem,
            jqDescriptionContent = jqDescription.find('.description'),
            jqEditor = jqCode.find('.code_editor'),
            jqTerminal = jqConsole.find('.console'),
            jqHints = jqInfo.find('.hints'),
            editor = CodeMirror(jqEditor[0], {
                cursorHeight: 0.85,
                lineNumbers: true,
                matchBrackets: true,
                mode: 'python',
                indentUnit: 4,
                extraKeys: {
                    // replace tabs with spaces
                    Tab: function (cm) {
                        var spaces = Array(cm.getOption("indentUnit") + 1).join(" ");
                        cm.replaceSelection(spaces);
                    }
                }
            }),
            activityHandler = makeActivityHandler(editor, problemDef.id),
            terminal = makePythonTerminalHandler(jqTerminal, editor, problemDef.id, activityHandler),
            hinter = codeq.makeHinter(jqHints, jqEditor, editor, 'python_hints', problemDef.hint, commonHints, problemDef.plan),
            commError = function (error) {
                alert(error);
            };

        codeq.tr.registerDictionary('python', problemDef.translations);
        codeq.tr.translateDom(jqScreen);
        if (currentSolution) editor.setValue(currentSolution);
//        $('#screen_python .title').text(problem.slug);
//        jqDescriptionContent.html(problem.description);
        jqBtnPlan.prop('disabled', ((problemDef.plan && problemDef.plan.sl) || []).length == 0);

        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.join(''))});
            }

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

        jqBtnPlan.on('click', function () {
            if (!hinter.planNext()) {
                jqBtnPlan.prop('disabled', true).blur();
            }
        });
        jqBtnHint.on('click', function () {
            var doc = editor.getDoc();
            codeq.comms.sendHint({
                'language': 'python',
                'program': editor.getDoc().getValue(),
                'problem_id': problemDef.id
            })
            .then(function (data) {
                if (data.code === 0) {
                    hinter.handle(data.hints);
                }
                else {
                    terminal.append('error: ' + data.message);
                }
            })
            .fail(commError)
            .done();
        });
        jqBtnTest.on('click', function () {
            var doc = editor.getDoc();
            codeq.comms.sendTest({
                'language': 'python',
                'program': editor.getDoc().getValue(),
                'problem_id': problemDef.id
            })
            .then(function (data) {
                if (data.code === 0) {
                    hinter.handle(data.hints);
                }
                else {
                    terminal.append('error: ' + data.message);
                }
            })
            .fail(commError)
            .done();
        });
        jqBtnRun.on('click', function () {
            var program = editor.getDoc().getValue();
            codeq.comms.sendPythonStop({})
            .then(function () {
                codeq.comms.sendPythonExec({
                    'program': program
                });
            })
            .fail(commError)
            .done();
            // focus the terminal
            jqTerminal.click();
        });
        jqBtnStop.on('click', function () {
            codeq.comms.sendPythonStop({})
            .fail(commError)
            .done();
        });

        // TODO first line of interpreter output is buffered without this, why?
        codeq.comms.sendPythonPush({
            'text': ''
        });

        return {
            destroy: function () {
                $('#screen_python .title').text('');//empty the title text
                jqAllButtons.off();
                editor.off('change');
                codeq.comms.off('terminal_output'); // stop listening for the terminal events from server
                hinter.destroy();
                terminal.destroy();
                jqDescriptionContent.empty();
                jqEditor.empty(); // TODO: perhaps you do not want to "free" the editor, just empty it
                jqTerminal.empty(); // TODO: the same with the console
                jqDescriptionContent = null;
                jqEditor = null;
                jqTerminal = null;
                jqHints = null;
                codeq.tr.registerDictionary('python', codeq.tr.emptyDictionary);
            }
        };
    };
})();