/*
 * ribbit.ts — core editor classes for the ribbit WYSIWYG markdown editor.
 */

import { HopDown } from './hopdown';
import { defaultTheme } from './default-theme';
import { ThemeManager } from './theme-manager';
import { RibbitEmitter, type RibbitEventMap } from './events';
import { type MacroDef } from './macros';
import { ToolbarManager } from './toolbar';
import type { RibbitTheme, ToolbarSlot } from './types';

export interface RibbitSettings {
    api?: unknown;
    editorId?: string;
    currentTheme?: string;
    themes?: RibbitTheme[];
    themesPath?: string;
    macros?: MacroDef[];
    toolbar?: ToolbarSlot[];
    /** Set to false to prevent auto-rendering the toolbar. Default true. */
    autoToolbar?: boolean;
    on?: Partial<RibbitEventMap>;
}

/**
 * Read-only markdown viewer. Renders markdown content into an HTML element.
 */
export class Ribbit {
    api: unknown;
    element: HTMLElement;
    states: Record<string, string>;
    cachedHTML: string | null;
    cachedMarkdown: string | null;
    state: string | null;
    changed: boolean;
    theme: RibbitTheme;
    themes: ThemeManager;
    converter: HopDown;
    themesPath: string;
    toolbar: ToolbarManager;
    protected autoToolbar: boolean;
    private emitter: RibbitEmitter;
    private macros: MacroDef[];

    constructor(settings: RibbitSettings) {
        this.api = settings.api || null;
        this.element = document.getElementById(settings.editorId || 'ribbit')!;
        this.themesPath = settings.themesPath || './themes';
        this.emitter = new RibbitEmitter();
        this.macros = settings.macros || [];
        this.states = {
            VIEW: 'view',
        };
        this.cachedHTML = null;
        this.cachedMarkdown = null;
        this.state = null;
        this.changed = false;

        this.themes = new ThemeManager(defaultTheme, this.themesPath, (theme, previous) => {
            this.theme = theme;
            this.converter = theme.tags
                ? new HopDown({ tags: theme.tags, macros: this.macros })
                : new HopDown({ macros: this.macros });
            this.cachedHTML = null;
            this.emitter.emit('themeChange', {
                current: theme,
                previous,
            });
            if (this.getState() === this.states.VIEW) {
                this.state = null;
                this.view();
            }
        });

        (settings.themes || []).forEach(theme => {
            this.themes.add(theme);
        });

        const activeName = settings.currentTheme || defaultTheme.name;
        this.themes.set(activeName);
        this.theme = this.themes.current();
        this.converter = this.theme.tags
            ? new HopDown({ tags: this.theme.tags, macros: this.macros })
            : new HopDown({ macros: this.macros });

        if (settings.on) {
            for (const [event, handler] of Object.entries(settings.on)) {
                if (handler) {
                    this.on(event as keyof RibbitEventMap, handler as any);
                }
            }
        }

        this.toolbar = new ToolbarManager(
            this,
            this.theme.tags || {},
            this.macros,
            settings.toolbar,
        );
        this.autoToolbar = settings.autoToolbar !== false;
    }

    on<K extends keyof RibbitEventMap>(event: K, callback: RibbitEventMap[K]): void {
        this.emitter.on(event, callback);
    }

    off<K extends keyof RibbitEventMap>(event: K, callback: RibbitEventMap[K]): void {
        this.emitter.off(event, callback);
    }

    run(): void {
        this.element.classList.add('loaded');
        if (this.autoToolbar) {
            this.element.parentNode?.insertBefore(this.toolbar.render(), this.element);
        }
        this.view();
        this.emitter.emit('ready', {
            markdown: this.getMarkdown(),
            html: this.getHTML(),
            mode: this.state || 'view',
            theme: this.theme,
        });
    }

    getState(): string | null {
        return this.state;
    }

    setState(newState: string): void {
        const previous = this.state;
        if (previous) {
            this.element.classList.remove(previous);
        }
        this.state = newState;
        this.element.classList.add(newState);
        this.emitter.emit('modeChange', {
            current: newState,
            previous,
        });
    }

    markdownToHTML(md: string): string {
        return this.converter.toHTML(md);
    }

    getHTML(): string {
        if (this.cachedHTML === null) {
            this.cachedHTML = this.markdownToHTML(this.getMarkdown());
        }
        return this.cachedHTML;
    }

    getMarkdown(): string {
        if (this.cachedMarkdown === null) {
            this.cachedMarkdown = this.element.textContent || '';
        }
        return this.cachedMarkdown;
    }

    save(): void {
        this.emitter.emit('save', {
            markdown: this.getMarkdown(),
            html: this.getHTML(),
        });
    }

    view(): void {
        if (this.getState() === this.states.VIEW) return;
        this.element.innerHTML = this.getHTML();
        this.setState(this.states.VIEW);
        this.element.contentEditable = 'false';
    }

    invalidateCache(): void {
        this.changed = true;
        this.cachedMarkdown = null;
        this.cachedHTML = null;
    }

    notifyChange(): void {
        this.emitter.emit('change', {
            markdown: this.getMarkdown(),
            html: this.getHTML(),
        });
    }
}

export function camelCase(words: string): string[] {
    return words.trim().split(/\s+/g).map(word => {
        const lc = word.toLowerCase();
        return lc.charAt(0).toUpperCase() + lc.slice(1);
    });
}

export function decodeHtmlEntities(html: string): string {
    const txt = document.createElement('textarea');
    txt.innerHTML = html;
    return txt.value;
}

export function encodeHtmlEntities(str: string): string {
    return str.replace(/[\u00A0-\u9999<>&]/g, i => '&#' + i.charCodeAt(0) + ';');
}