/**
 * Handler for a Python assignment. Works with the corresponding python.html content.
 */

(function () {
    // 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'
            }),
            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) {
            return codeq.comms.sendPush({
                'text': text + '\n'
            }).then(tcs, tcf);
        };

        codeq.comms.on('terminal_output', function (data) {
            var text = data.text;
            terminal.append(text, 'output');
            lines = text.split('\n');
            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) setTimeout(timer, 10000); // flush every 10 seconds
            },
            '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}}
     */
    codeq.createPythonHandler = 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, mode: 'python' }),
            activityHandler = makeActivityHandler(editor, problem.id),
            terminal = makePythonTerminalHandler(jqConsole, editor, problem.id, activityHandler),
            hintDefs = problem.hint,
            hintCounter = 0, // for generating unique class-names
            hintCleaners = [],
            clearHints = function () {
                var i;
                for (i = hintCleaners.length - 1; i >= 0; i--) {
                    hintCleaners[i]();
                }
                hintCleaners.length = 0;
                hintCounter = 0;
            },
            addMark = function (start, end) {
                var posStart = editor.posFromIndex(start),
                    posEnd = editor.posFromIndex(end),
                    doc = editor.getDoc(),
                    mark = doc.markText(posStart, posEnd, {className: 'editor-mark _emark_' + hintCounter}),
                    result = {start: posStart, end: posEnd, mark: mark, className: '_emark_' + hintCounter};
                hintCleaners.push(function () { mark.clear(); mark = null; doc = null; result.mark = null; });
                hintCounter++;
                return result;
            },
            processTemplate = function (template, args) {
                if (!args)
                    return template;
                return template.replace(/\[%=(\w+)%\]/g, function(match, name) {
                    return args[name];
                });
            },
            hintHandlers = {
                'static': function (type, template, serverHint) {
                    codeq.log.debug('Processing static hint');
                    var message = processTemplate(template, serverHint.args);
                    jqHints.append('<div class="hint-static">' + message + '</div>');
                    // no hint cleaner here, a static hint remains on the screen
                },
                'popup': function (type, template, serverHint) {
                    codeq.log.debug('Processing popup hint');
                    var message = processTemplate(template, serverHint.args),
                        mark = addMark(serverHint.start, serverHint.end), // add the mark
                        jqMark = jqEditor.find('.' + mark.className);
/*                        jqPopup = null,
                        onBlur = function () {
                            codeq.log.debug('Removing popup');
                            if (jqPopup) {
                                jqPopup.off('blur', onBlur);
                                jqPopup.remove();
                                jqPopup = null;
                            }
                        };

                    window.jqMark = jqMark; // TODO: DEBUG

                    jqMark.on('click', function () {
                        if (jqPopup) return;
                        codeq.log.debug('Showing popup');
                        var pos = mark.mark.find(), // results in {from: {line: number, ch: number}, to: {line: number, ch: number}}
                            left = pos.from.ch < pos.to.ch ? pos.from.ch : pos.to.ch,
                            down = pos.from.line < pos.to.line ? pos.to.line : pos.from.line;
                        jqPopup = $('<div style="position: absolute;" class="editor-popup ' + mark.className + '"></div>').html(template);
                        editor.addWidget({line: down, ch: left}, jqPopup[0], true);
                        jqPopup = jqEditor.find('.editor-popup.' + mark.className);
                        setTimeout(function () {jqPopup.trigger('focus'); jqPopup.on('click', onBlur);}, 50); // event handlers can be registered only when the DOM elements is part of the document
                        window.jqPopup = jqPopup; // TODO: DEBUG
                    });

                    hintCleaners.push(function () {
                        if (jqPopup) {
                            jqPopup.off('blur', onBlur);
                            jqPopup.remove();
                            jqPopup = null;
                        }
                        if (jqMark) {
                            jqMark = null;
                        }
                        mark = null;
                    });*/

                    jqMark.popover({content: message, html: true, placement: 'auto bottom', trigger: 'hover focus click', container: 'body'});
                    hintCleaners.push(function () { if (jqMark) { jqMark.popover('destroy'); jqMark = null; } });

                    mark.mark.on('', function () {});
                },
                'dropdown': function (type, template, serverHint) {
                    codeq.log.debug('Processing dropdown hint');
                    var completion = null, // the completion object, created in showHint()
                        close = function () {
                            if (completion) {
                                completion.close();
                                completion = null;
                            }
                        };

                    if ((editor.listSelections().length > 1) || editor.somethingSelected()) {
                        // showHint() doesn't work if a selection is activeparts
                    }

                    editor.showHint({
                        hint: function () {
                            var hints = {
                                list: serverHint.choices,
                                from: editor.posFromIndex(serverHint.start),
                                to: editor.posFromIndex(serverHint.end)
                            };
                            completion = editor.state.completionActive;
                            return hints;
                        },
                        completeOnSingleClick: true,
                        completeSingle: false
                    });

                    hintCleaners.push(close);
                }
            };

        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});
            }
        });

        var handler = {
            destroy: function () {
                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
                jqHints.empty(); // TODO: just make static references to these
                jqDescription = null;
                jqEditor = null;
                jqConsole = null;
                jqHints = null;
            },

            /**
             * Processes and display appropriately the server hints.
             * TODO: sort hints so static and popup hints come first, and a (single) drop-down hint last
             *
             * @param {ServerHint[]} serverHints an array of hints from the server
             */
            processServerHints: function (serverHints) {
                var n = serverHints.length,
                    /** number */ i,
                    /** ServerHint */ serverHint,
                    /** HintDefinition */ hintDef,
                    hintType, hintTemplate, t, fn;
                clearHints();
                for (i = 0; i < n; i++) {
                    serverHint = serverHints[i];
                    hintDef = hintDefs[serverHint.id];
                    if (serverHint.indices) {
                        indices = serverHint.indices
                        for (i = 0; i < indices.length; i++) {
                            hintDef = hintDef[indices[i]];
                            if (!hintDef)
                                break;
                        }
                    }
                    if (!hintDef) {
                        codeq.log.error('Undefined hint ' + serverHint.id + ' with indices ' + serverHint.indices);
                        continue;
                    }
                    t = typeof hintDef;
                    if (t === 'object') {
                        hintType = hintDef.type;
                        hintTemplate = hintDef.message;
                    }
                    else if (t === 'string') {
                        hintType = 'static';
                        hintTemplate = hintDef;
                    }
                    else {
                        codeq.log.error('Unsupported hint definition: ' + t);
                        continue;
                    }

                    fn = hintHandlers[hintType];
                    if (!fn) codeq.log.error('Unsupported hint type: ' + hintType);
                    else fn(hintType, hintTemplate, serverHint);
                }
            }
        };

        var jqButtons = $('#block-toolbar button');
//        $(jqButtons.get(0)).on('click', function () { handler.processServerHints([{id:'x_must_be_female'}]); });
//        $(jqButtons.get(1)).on('click', function () { handler.processServerHints([{id:'popup_unknown', start: 20, end: 26}]); });
//        $(jqButtons.get(2)).on('click', function () { handler.processServerHints([{id:'drop_down', start: 20, end: 26, choices:['ena', 'dva', 'tri']}]); });

        $('#btn_code_hint').on('click', function () {
//            handler.processServerHints([{id:'drop_down', start: 20, end: 26, choices:['ena', 'dva', 'tri']}]);
            var doc = editor.getDoc();
            codeq.comms.sendHint({
                'language': 'python',
                'program': editor.getDoc().getValue(),
                'problem_id': problem.id
            }).then(
                function hintSuccess(data) {
                    if (data.code === 0)
                        handler.processServerHints(data.hints);
                    else
                        terminal.append('error: ' + data.message);
                },
                function hintFailed (error) {
                    terminal.append('exception: ' + error);
                }
            ).done();
        });
        $('#btn_code_test').on('click', function () {
            var doc = editor.getDoc();
            codeq.comms.sendTest({
                'language': 'python',
                'program': editor.getDoc().getValue(),
                'problem_id': problem.id
            }).then(
                function testSuccess(data) {
                    if (data.code === 0)
                        handler.processServerHints(data.hints);
                    else
                        terminal.append('error: ' + data.message);
                },
                function testFailed (error) {
                    terminal.append('exception: ' + error);
                }
            ).done();
        });

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

        return handler;
    };
})();