/* global TokenType, ViewActivity, TextUtils, Variables, Operator */

function Parser(tokens) {
    this.tokens = tokens;
    this.tokensCount = tokens.length;
    this.position = 0;
    this.lastPosition = 0;
    this.labels = {};
    /** Оптимизация, чтобы каждый раз не искать endmenu/endif,
     * если их попросту нет в необработанном сценарии */
    this.hasEndMenu = false;
    this.hasEndIf = false;
    Variables.init();
}

Parser.prototype.EOF = new Token("", TokenType.EOF);

Parser.prototype.getInstance = function () {
    return this;
};

Parser.prototype.setPosition = function (position) {
    this.position = position;
    this.next();
};

Parser.prototype.jumpLabel = function (label) {
    if (label in this.labels) {
        this.position = this.labels[label];
    }
};

Parser.prototype.next = function () {
    this.lastPosition = this.position;
    
    var terminal = false;
    var counter = 0;
    do {
        try {
            terminal = this.statement();
        } catch (re) {
            console.log("Parser.next() " + re);
            if (this.tokens.length === 0) return;
        }
        // антизацикливание
        counter++;
        if (counter >= 1000) {
            this.position++;
            counter = 0;
        }
    } while (!terminal);
};

Parser.prototype.findFrom = function(from, which, step) {
    var pos = from;
    while (true) {
        pos += step;
        if (pos < 0 || pos >= this.tokensCount) break;

        var token = this.tokens[pos];
        if (which === token.getType()) return pos;
    }
    // Возвращаем текущее значение во избежание лишних проверок.
    return from;
};

Parser.prototype.statement = function() {
    var token = this.get(0);
    if (this.match(token, TokenType.COMMAND)) return this.command();
    if (this.match(token, TokenType.SCENE)) return this.scene();
    if (this.match(token, TokenType.PLAY)) return this.play();
    if (this.match(token, TokenType.QUEUE)) return this.queue();
    if (this.match(token, TokenType.STOP)) return this.stop();
    if (this.match(token, TokenType.SHOW)) return this.show();
    if (this.match(token, TokenType.HIDE)) return this.hide();
    
    if (this.match(token, TokenType.JUMP)) return this.jump();
    if (this.match(token, TokenType.IF)) return this.ifStatement();

    if (this.lookMatch(1, TokenType.COLON)) {
        // menu:
        if (this.match(token, TokenType.MENU)) return this.menu();

        // Остаток от меню выбора. Пропускаем до появления ENDMENU.
        if (this.match(token, TokenType.TEXT)) {
            if (this.hasEndMenu) this.position += this.skipMenu();
            return false;
        }

        // Остаток от условного выражения. Пропускаем до появления ENDIF.
        if (this.match(token, TokenType.ELSE)) {
            if (this.hasEndIf) this.position += this.skipIf();
            return false;
        }
    }

    // Текст с именем автора реплики.
    if (this.lookMatch(1, TokenType.TEXT) && this.match(token, TokenType.WORD)) {
        var whoid = token.getText();
        ViewActivity.getInstance().text(whoid, this.consume(TokenType.TEXT).getText());
        return true;
    }

    // Обычный текст.
    if (this.match(token, TokenType.TEXT)) {
        ViewActivity.getInstance().text(token.getText());
        return true;
    }

    if (this.match(token, TokenType.EOF)) {
        ViewActivity.getInstance().finish();
        return true;
    }

    if (this.match(token, TokenType.WINDOW)) {
        if (this.match(TokenType.SHOW))
            return ViewActivity.getInstance().windowShow(this.matchWithEffect());
        else if (this.match(TokenType.HIDE))
            return ViewActivity.getInstance().windowHide(this.matchWithEffect());
        return false;
    }

    if (!TextUtils.isEmpty(this.matchWithEffect())) return false;

    this.position++;
    return false;
};

Parser.prototype.command = function() {
    var token = this.get(0);
    
    if (this.match(token, TokenType.RENPY_PAUSE)) {
        this.consume(TokenType.LPAREN);
        var pause = this.consumeDouble();
        var hard = false;
        if (!this.lookMatch(0, TokenType.RPAREN)) {
            this.consume(TokenType.WORD); // hard
            this.consume(TokenType.EQ);
            hard = this.consumeBoolean();
        }
        this.consume(TokenType.RPAREN);
        ViewActivity.getInstance().pause(Math.floor(1000 * pause), hard);
        return true;
    }

    if (this.match(token, TokenType.RENPY_SAY)) {
        this.consume(TokenType.LPAREN);
        var whoid = this.consume(TokenType.WORD).getText();
        // TODO: this.consume(TokenType.COMMA)
        var text = this.consume(TokenType.TEXT).getText();
        // TODO: this.consume(TokenType.COMMA)
        this.consume(TokenType.WORD); // interact
        this.consume(TokenType.EQ);
        var interact = this.consumeBoolean();
        this.consume(TokenType.RPAREN);
        ViewActivity.getInstance().text(whoid, text);
        return interact;
    }

    if (this.match(token, TokenType.PERSISTENT_SPRITE_TIME)) {
        this.consume(TokenType.EQ);
        this.consume(TokenType.TEXT);
        return false;
    }

    if (this.match(token, TokenType.PROLOG_TIME) ||
            this.match(token, TokenType.DAY_TIME) ||
            this.match(token, TokenType.SUNSET_TIME) ||
            this.match(token, TokenType.NIGHT_TIME)) {
        this.consume(TokenType.LPAREN);
        this.consume(TokenType.RPAREN);
        return false;
    }

    if (this.match(token, TokenType.MAKE_NAMES_KNOWN) ||
            this.match(token, TokenType.MAKE_NAMES_UNKNOWN)) {
        this.consume(TokenType.LPAREN);
        this.consume(TokenType.RPAREN);
        if (token.getType() === TokenType.MAKE_NAMES_KNOWN) {
            ViewActivity.getInstance().makeNamesKnown();
        } else ViewActivity.getInstance().makeNamesUnknown();
        return false;
    }

    if (this.match(token, TokenType.SET_NAME)) {
        this.consume(TokenType.LPAREN);
        var whoid = this.consume(TokenType.TEXT).getText();
        // TODO: this.consume(TokenType.COMMA)
        var name = this.consume(TokenType.TEXT).getText();
        this.consume(TokenType.RPAREN);
        ViewActivity.getInstance().meet(whoid, name);
        return false;
    }

    // Карта
    if (this.match(token, TokenType.DISABLE_ALL_ZONES)) {
        this.consume(TokenType.LPAREN);
        this.consume(TokenType.RPAREN);
        ViewActivity.getInstance().disableAllZones();
        return false;
    }
    if (this.match(token, TokenType.DISABLE_CURRENT_ZONE)) {
        this.consume(TokenType.LPAREN);
        this.consume(TokenType.RPAREN);
        ViewActivity.getInstance().disableCurrentZone();
        return false;
    }
    if (this.match(token, TokenType.RESET_ZONE)) {
        this.consume(TokenType.LPAREN);
        var zone = this.consume(TokenType.TEXT).getText();
        this.consume(TokenType.RPAREN);
        ViewActivity.getInstance().resetZone(zone);
        return false;
    }
    if (this.match(token, TokenType.SET_ZONE)) {
        this.consume(TokenType.LPAREN);
        var zone = this.consume(TokenType.TEXT).getText();
        // TODO: this.consume(TokenType.COMMA)
        var label = this.consume(TokenType.TEXT).getText();
        this.consume(TokenType.RPAREN);
        ViewActivity.getInstance().setZone(zone, label);
        return false;
    }
    if (this.match(token, TokenType.SHOW_MAP)) {
        this.consume(TokenType.LPAREN);
        this.consume(TokenType.RPAREN);
        ViewActivity.getInstance().showMap();
        return true;
    }

    if (this.match(token, TokenType.WORD)) {
        if (this.match(TokenType.EQ)) {
            // variable = expression
            Variables.setVariable(token.getText(), this.expression().eval());
            return false;
        }
        if (this.lookMatch(1, TokenType.EQ) && this.match(TokenType.PLUS)) {
            // variable += expression
            this.consume(TokenType.EQ);
            var varValue = Variables.getVariable(token.getText());
            Variables.setVariable(token.getText(), varValue + this.expression().eval());
            return false;
        }
        if (this.lookMatch(1, TokenType.EQ) && this.match(TokenType.MINUS)) {
            // variable -= expression
            this.consume(TokenType.EQ);
            var varValue = Variables.getVariable(token.getText());
            Variables.setVariable(token.getText(), varValue - this.expression().eval());
            return false;
        }
    }

    return false;
};

Parser.prototype.scene = function() {
    var type = "";
    if (this.match(TokenType.BG)) type = "bg";
    else if (this.match(TokenType.CG)) type = "cg";
    else if (this.match(TokenType.ANIM)) type = "anim";
    
    var name = this.consume(TokenType.WORD).getText();
    var effect = this.matchWithEffect();
    ViewActivity.getInstance().background(type, name, effect);
    return true;
};

Parser.prototype.show = function() {
    var whoid =  this.consume(TokenType.WORD).getText();
    var params = ""; // emotion? cloth? distance?
    while (this.lookMatch(0, TokenType.WORD)) {
        var text = this.consume(TokenType.WORD).getText();
        params += text;
        if (text.equals("close") || text.equals("far")) break;
    }
    // Положение (left, cleft, ...)
    var position = "";
    if (this.match(TokenType.AT)) {
        position = this.consume(TokenType.WORD).getText();
    }
    // Псевдоним (для показа одно и того же спрайта в разных местах)
    var alias = "";
    if (this.match(TokenType.AS)) {
        alias = this.consume(TokenType.WORD).getText();
    }
    var effect = this.matchWithEffect();
    ViewActivity.getInstance().sprite(whoid, params, position, alias, effect);
    return false;
};

Parser.prototype.hide = function() {
    var whoid =  this.consume(TokenType.WORD).getText();
    var effect = this.matchWithEffect();
    ViewActivity.getInstance().hideSprite(whoid, effect);
    return false;
};

Parser.prototype.play = function() {
    if (this.match(TokenType.MUSIC)) return this.playMusic();
    if (this.match(TokenType.AMBIENCE)) return this.playAmbience();
    if (this.lookMatch(0, TokenType.SOUND) || this.lookMatch(0, TokenType.SOUNDLOOP)) {
        return this.playSound();
    }
    return false;
};

Parser.prototype.playMusic = function() {
    var name = this.consumeMusicName();
    var fade = this.matchFade();
    ViewActivity.getInstance().music(name, fade);
    return false;
};

Parser.prototype.playSound = function() {
    var loop = false;
    if (this.match(TokenType.SOUND)) loop = false;
    else if (this.match(TokenType.SOUNDLOOP)) loop = true;
    
    var name = this.consumeMusicName();
    var fade = this.matchFade();
    ViewActivity.getInstance().sound(name, loop, fade);
    return false;
};

Parser.prototype.playAmbience = function() {
    var name = this.consumeMusicName();
    var fade = this.matchFade();
    return false;
};

Parser.prototype.queue = function() {
    if (this.match(TokenType.MUSIC)) return this.queueMusic();
    if (this.match(TokenType.SOUND)) return this.queueSound();
    return false;
};

Parser.prototype.queueMusic = function() {
    var name = this.consumeMusicName();
    ViewActivity.getInstance().addMusicToQueue(name);
    return false;
};

Parser.prototype.queueSound = function() {
    var name = this.consumeMusicName();
    ViewActivity.getInstance().addSoundToQueue(name);
    return false;
};

Parser.prototype.stop = function() {
    if (this.match(TokenType.MUSIC)) {
        var fade = this.matchFade();
        ViewActivity.getInstance().stopMusic(fade);
    }
    if (this.match(TokenType.SOUND) || this.match(TokenType.SOUNDLOOP)) {
        var fade = this.matchFade();
        ViewActivity.getInstance().stopSound(fade);
    }
    if (this.match(TokenType.AMBIENCE)) {
        var fade = this.matchFade();
        // ViewActivity.getInstance().stopAmbience(fade);
    }
    return false;
};

Parser.prototype.menu = function() {
    // menu: title?
    this.consume(TokenType.COLON);

    var title = "";
    if (this.lookMatch(0, TokenType.TEXT) && !this.lookMatch(1, TokenType.COLON)) {
        title = this.consume(TokenType.TEXT).getText();
    }

    if (!this.hasEndMenu) return false;
    // Ищем элементы выбора
    var menu = new Menu(title);
    var pos = 0;
    var level = 1; // уровень вложенности меню
    while (true) {
        // Расчёт уровня меню.
        if (this.lookMatch(pos, TokenType.MENU) && this.lookMatch(pos + 1, TokenType.COLON)) {
            level++;
            pos++;
        }
        if (this.lookMatch(pos, TokenType.ENDMENU)) {
            level--;
            // Завершаем работу по достижению ENDMENU первого уровня.
            if (level <= 0) break;
        }

        if (level == 1) {
            // Добавляем только пункты из меню первого уровня.
            if (this.lookMatch(pos, TokenType.TEXT) && this.lookMatch(pos + 1, TokenType.COLON)) {
                menu.addItem(this.get(pos).getText(), this.position + pos + 2);
                pos++;
            }
        }

        if (this.lookMatch(pos, TokenType.EOF)) return false;
        pos++;
    }

    ViewActivity.getInstance().menu(menu);
    return true;
};

Parser.prototype.jump = function() {
    var labelName = this.consume(TokenType.WORD).getText();
    this.jumpLabel(labelName);
    return false;
};

Parser.prototype.ifStatement = function() {
    var condition = this.expression();
    this.consume(TokenType.COLON);

    if (!this.hasEndIf) return false;
    if (condition.eval() == 0) {
        // Если условие не верно, пропускаем блок до следующего ENDIF
        var pos = 0;
        var level = 1; // уровень вложенности блока
        while (true) {
            // Расчёт уровня блока.
            if (this.lookMatch(pos, TokenType.IF)) {
                level++;
                pos++;
            }
            if (this.lookMatch(pos, TokenType.ELSE)) {
                level--;
                pos += 2; // пропускаем ELSE и двоеточие
                // Завершаем работу по достижению ELSE первого уровня.
                if (level <= 0) break;
            }
            if (this.lookMatch(pos, TokenType.ENDIF)) {
                level--;
                // Завершаем работу по достижению ENDIF первого уровня.
                if (level <= 0) break;
            }

            if (this.lookMatch(pos, TokenType.EOF)) return false;
            pos++;
        }
        this.position += pos;
    }
    return false;
};

Parser.prototype.expression = function() {
    return this.orTest();
};

Parser.prototype.orTest = function() {
    var expression = this.andTest();
    
    while (true) {
        if (this.match(TokenType.OR)) {
            expression = new BinaryExpression(Operator.BOOLEAN_OR, expression, this.andTest());
            continue;
        }
        break;
    }
    
    return expression;
};

Parser.prototype.andTest = function() {
    var expression = this.notTest();
    
    while (true) {
        if (this.match(TokenType.AND)) {
            expression = new BinaryExpression(Operator.BOOLEAN_AND, expression, this.notTest());
            continue;
        }
        break;
    }
    
    return expression;
};

Parser.prototype.notTest = function() {
    if (this.match(TokenType.NOT)) {
        return new ValueExpression( this.notTest().eval() != 0 ? 0 : 1 );
    }
    return this.comparison();
};

Parser.prototype.comparison = function() {
    var expression = this.additive();
    
    while (true) {
        if (this.lookMatch(1, TokenType.EQ)) {
            if (this.match(TokenType.EQ)) {
                // ==
                this.consume(TokenType.EQ);
                expression = new BinaryExpression(Operator.EQUALS, expression, this.additive());
                continue;
            }
            if (this.match(TokenType.GT)) {
                // >=
                this.consume(TokenType.EQ);
                expression = new BinaryExpression(Operator.GTEQ, expression, this.additive());
                continue;
            }
            if (this.match(TokenType.LT)) {
                // <=
                this.consume(TokenType.EQ);
                expression = new BinaryExpression(Operator.LTEQ, expression, this.additive());
                continue;
            }
            if (this.match(TokenType.EXCL)) {
                // !=
                this.consume(TokenType.EQ);
                expression = new BinaryExpression(Operator.NOTEQUALS, expression, this.additive());
                continue;
            }
        }

        if (this.match(TokenType.LT)) {
            expression = new BinaryExpression(Operator.LT, expression, this.additive());
            continue;
        }
        if (this.match(TokenType.GT)) {
            expression = new BinaryExpression(Operator.GT, expression, this.additive());
            continue;
        }
        break;
    }
    
    return expression;
};

Parser.prototype.additive = function() {
    var expression = this.unary();
    
    while (true) {
        if (this.match(TokenType.PLUS)) {
            expression = new BinaryExpression(Operator.ADD, expression, this.unary());
            continue;
        }
        if (this.match(TokenType.MINUS)) {
            expression = new BinaryExpression(Operator.SUBTRACT, expression, this.unary());
            continue;
        }
        break;
    }
    
    return expression;
};

Parser.prototype.unary = function() {
    if (this.match(TokenType.MINUS)) {
        return new ValueExpression( -this.primary().eval() );
    }
    if (this.match(TokenType.PLUS)) {
        return this.primary();
    }
    return this.primary();
};

Parser.prototype.primary = function() {
    var current = this.get(0);
    if (this.match(current, TokenType.NUMBER)) {
        return new ValueExpression( parseFloat(current.getText()) );
    }
    if (this.match(current, TokenType.WORD)) {
        return new VariableExpression(current.getText());
    }
    if (this.match(current, TokenType.LPAREN)) {
        var expr = this.expression();
        this.match(TokenType.RPAREN);
        return expr;
    }
    throw "Неизвестное выражение";
};

Parser.prototype.preScan = function() {
    // Сканируем все метки, для быстрого перехода командой jump.
    // А также определяем параметры для оптимизации.
    for (var i = 0; i < this.tokensCount - 2; i++) {
        var current = this.tokens[i].getType();
        if (current === TokenType.ENDMENU) {
            this.hasEndMenu = true;
        } else if (current === TokenType.ENDIF) {
            this.hasEndIf = true;
        } else if ( (current === TokenType.LABEL) &&
             (this.tokens[i + 2].getType() === TokenType.COLON) ) {
            // label word :
            var token = this.tokens[i + 1];
            if (token.getType() === TokenType.WORD) {
                // Добавляем позицию команды, следующей после метки.
                this.labels[token.getText()] = i + 3;
            }
            i += 2;
        }
    }
};

Parser.prototype.skipMenu = function() {
    var pos = 0;
    var level = 1; // уровень вложенности меню
    while (true) {
        // Расчёт уровня меню.
        if (this.lookMatch(pos, TokenType.MENU) && this.lookMatch(pos + 1, TokenType.COLON)) {
            level++;
            pos += 2;
        }
        if (this.lookMatch(pos, TokenType.ENDMENU)) {
            pos++;
            level--;
            // Завершаем работу по достижению ENDMENU первого уровня.
            if (level <= 0) break;
        }
        if (this.lookMatch(pos, TokenType.EOF)) return 0;
        pos++;
    }
    return pos;
};

Parser.prototype.skipIf = function() {
    var pos = 0;
    var level = 1;
    while (true) {
        if (this.lookMatch(pos, TokenType.IF)) level++;
        else if (this.lookMatch(pos, TokenType.ENDIF)) {
            pos++;
            level--;
            if (level <= 0) break;
        } else if (this.lookMatch(pos, TokenType.EOF)) return 0;
        pos++;
    }
    return pos;
};


Parser.prototype.consumeMusicName = function() {
    var name = "";
    if (this.lookMatch(1, TokenType.LBRACKET)) {
        // music_list["music"]
        this.consume(TokenType.WORD);
        this.consume(TokenType.LBRACKET);
        name = this.consume(TokenType.TEXT).getText();
        this.consume(TokenType.RBRACKET);
    } else if (this.lookMatch(0, TokenType.TEXT)) {
        name = this.consume(TokenType.TEXT).getText();
    } else {
        name = this.consume(TokenType.WORD).getText();
    }
    return name;
};

Parser.prototype.matchFade = function() {
    var result = new FadeInfo();
    if (this.match(TokenType.FADEIN)) {
        result.fadeIn = true;
        result.duration = this.consumeDouble();
    } else if (this.match(TokenType.FADEOUT)) {
        result.fadeOut = true;
        result.duration = this.consumeDouble();
    }
    return result;
};

Parser.prototype.matchWithEffect = function() {
    if (this.match(TokenType.WITH)) {
        return this.consume(TokenType.WORD).getText();
    }
    return "";
};

Parser.prototype.consumeDouble = function() {
    return parseFloat(this.consume(TokenType.NUMBER).getText());
};

Parser.prototype.consumeBoolean = function() {
    return "true" === (this.consume(TokenType.WORD).getText().toLowerCase());
};

Parser.prototype.matchWithEffect = function() {
    if (this.match(TokenType.WITH)) {
        return this.consume(TokenType.WORD).getText();
    }
    return "";
};

Parser.prototype.match_1 = function(type) {
    if (this.get(0).getType() !== type) return false;
    this.position++;
    return true;
};
Parser.prototype.match_2 = function(token, type) {
    if (type !== token.getType()) return false;
    this.position++;
    return true;
};
Parser.prototype.match = function(arg1, arg2) {
    if (arguments.length === 1) return this.match_1(arg1);
    else return this.match_2(arg1, arg2);
};

Parser.prototype.consume = function(type) {
    if (this.get(0).getType() !== type) throw "Ожидался токен " + type + ", но получен " + this.get(0);
    return this.tokens[this.position++];
};

Parser.prototype.lookMatch = function(pos, type) {
    return (type === this.get(pos).getType());
};

Parser.prototype.get = function(offset) {
    if (this.position + offset >= this.tokensCount) return this.EOF;
    return this.tokens[this.position + offset];
};