fchat-rising/bbcode/parser.ts

abstract class BBCodeTag {
    noClosingTag = false;
    allowedTags: {[tag: string]: boolean | undefined} | undefined;

    constructor(public tag: string, tagList?: string[]) {
        if(tagList !== undefined)
            this.setAllowedTags(tagList);
    }

    isAllowed(tag: string): boolean {
        return this.allowedTags === undefined || this.allowedTags[tag] !== undefined;
    }

    setAllowedTags(allowed: string[]): void {
        this.allowedTags = {};
        for(const tag of allowed)
            this.allowedTags[tag] = true;
    }

    abstract createElement(parser: BBCodeParser, parent: HTMLElement, param: string, content: string): HTMLElement | undefined;
}

export class BBCodeSimpleTag extends BBCodeTag {

    constructor(tag: string, private elementName: keyof HTMLElementTagNameMap, private classes?: string[], tagList?: string[]) {
        super(tag, tagList);
    }

    createElement(parser: BBCodeParser, parent: HTMLElement, param: string): HTMLElement {
        if(param.length > 0)
            parser.warning('Unexpected parameter');
        const el = <HTMLElement>parser.createElement(this.elementName);
        if(this.classes !== undefined && this.classes.length > 0)
            el.className = this.classes.join(' ');
        parent.appendChild(el);
        /*tslint:disable-next-line:no-unsafe-any*/// false positive
        return el;
    }
}

export class BBCodeCustomTag extends BBCodeTag {
    constructor(tag: string, private customCreator: (parser: BBCodeParser, parent: HTMLElement, param: string) => HTMLElement | undefined,
                tagList?: string[]) {
        super(tag, tagList);
    }

    createElement(parser: BBCodeParser, parent: HTMLElement, param: string): HTMLElement | undefined {
        return this.customCreator(parser, parent, param);
    }
}

export class BBCodeTextTag extends BBCodeTag {
    constructor(tag: string, private customCreator: (parser: BBCodeParser, parent: HTMLElement,
                                                     param: string, content: string) => HTMLElement | undefined) {
        super(tag, []);
    }

    createElement(parser: BBCodeParser, parent: HTMLElement, param: string, content: string): HTMLElement | undefined {
        return this.customCreator(parser, parent, param, content);
    }
}

export class BBCodeParser {
    private _warnings: string[] = [];
    private _tags: {[tag: string]: BBCodeTag | undefined} = {};
    private _line = -1;
    private _column = -1;
    private _storeWarnings = false;
    private _currentTag!: {tag: string, line: number, column: number};

    parseEverything(input: string): HTMLElement {
        if(input.length === 0)
            return this.createElement('span');
        this._warnings = [];
        this._line = 1;
        this._column = 1;
        const parent = document.createElement('span');
        parent.className = 'bbcode';
        this._currentTag = {tag: '<root>', line: 1, column: 1};
        this.parse(input, 0, undefined, parent, () => true);

        //if(process.env.NODE_ENV !== 'production' && this._warnings.length > 0)
        //    console.log(this._warnings);
        return parent;
    }

    createElement<K extends keyof HTMLElementTagNameMap>(tag: K): HTMLElementTagNameMap[K] {
        return document.createElement(tag);
    }

    addTag(impl: BBCodeTag): void {
        this._tags[impl.tag] = impl;
    }

    removeTag(tag: string): void {
        delete this._tags[tag];
    }

    get warnings(): ReadonlyArray<string> {
        return this._warnings;
    }

    set storeWarnings(store: boolean) {
        this._storeWarnings = store;
        if(!store)
            this._warnings = [];
    }

    warning(message: string): void {
        if(!this._storeWarnings)
            return;
        const cur = this._currentTag;
        const newMessage = `Error on ${this._line}:${this._column} while inside tag [${cur.tag} @ ${cur.line}:${cur.column}]: ${message}`;
        this._warnings.push(newMessage);
    }

    private parse(input: string, start: number, self: BBCodeTag | undefined, parent: HTMLElement | undefined,
                  isAllowed: (tag: string) => boolean): number {
        let currentTag = this._currentTag;
        const selfAllowed = self !== undefined ? isAllowed(self.tag) : true;
        if(self !== undefined) {
            const parentAllowed = isAllowed;
            isAllowed = (name) => self.isAllowed(name) && parentAllowed(name);
            currentTag = this._currentTag = {tag: self.tag, line: this._line, column: this._column};
        }
        let tagStart = -1, paramStart = -1, mark = start;
        for(let i = start; i < input.length; ++i) {
            const c = input[i];
            ++this._column;
            if(c === '\n') {
                ++this._line;
                this._column = 1;
            }
            if(c === '[') {
                tagStart = i;
                paramStart = -1;
            } else if(c === '=' && paramStart === -1)
                paramStart = i;
            else if(c === ']') {
                const paramIndex = paramStart === -1 ? i : paramStart;
                let tagKey = input.substring(tagStart + 1, paramIndex).trim().toLowerCase();
                if(tagKey.length === 0) {
                    tagStart = -1;
                    continue;
                }
                const param = paramStart > tagStart ? input.substring(paramStart + 1, i).trim() : '';
                const close = tagKey[0] === '/';
                if(close) tagKey = tagKey.substr(1).trim();
                if(this._tags[tagKey] === undefined) {
                    tagStart = -1;
                    continue;
                }
                if(!close) {
                    const tag = this._tags[tagKey]!;
                    const allowed = isAllowed(tagKey);
                    if(parent !== undefined) {
                        parent.appendChild(document.createTextNode(input.substring(mark, allowed ? tagStart : i + 1)));
                        mark = i + 1;
                    }
                    if(!allowed || parent === undefined) {
                        i = this.parse(input, i + 1, tag, parent, isAllowed);
                        mark = i + 1;
                        continue;
                    }
                    let element: HTMLElement | undefined;
                    if(tag instanceof BBCodeTextTag) {
                        i = this.parse(input, i + 1, tag, undefined, isAllowed);
                        element = tag.createElement(this, parent, param, input.substring(mark, input.lastIndexOf('[', i)));
                        if(element === undefined) parent.appendChild(document.createTextNode(input.substring(tagStart, i + 1)));
                    } else {
                        element = tag.createElement(this, parent, param, '');
                        if(element === undefined) parent.appendChild(document.createTextNode(input.substring(tagStart, i + 1)));
                        if(!tag.noClosingTag)
                            i = this.parse(input, i + 1, tag, element !== undefined ? element : parent, isAllowed);
                        if(element === undefined)
                            parent.appendChild(document.createTextNode(input.substring(input.lastIndexOf('[', i), i + 1)));
                    }
                    mark = i + 1;
                    this._currentTag = currentTag;
                    if(element === undefined) continue;
                    (<HTMLElement & {bbcodeTag: string}>element).bbcodeTag = tagKey;
                    if(param.length > 0) (<HTMLElement & {bbcodeParam: string}>element).bbcodeParam = param;
                } else if(self !== undefined) { //tslint:disable-line:curly
                    if(self.tag === tagKey) {
                        if(parent !== undefined)
                            parent.appendChild(document.createTextNode(input.substring(mark, selfAllowed ? tagStart : i + 1)));
                        return i;
                    }
                    if(!selfAllowed) return mark - 1;
                    if(isAllowed(tagKey))
                         this.warning(`Unexpected closing ${tagKey} tag. Needed ${self} tag instead.`);
                } else if(isAllowed(tagKey)) this.warning(`Found closing ${tagKey} tag that was never opened.`);
            }
        }
        if(mark < input.length && parent !== undefined) {
            parent.appendChild(document.createTextNode(input.substring(mark)));
            mark = input.length;
        }
        if(self !== undefined) this.warning('Automatically closing tag at end of input.');
        return mark;
    }
}