import { Editor } from '../../editor/Editor.js';
import { ContextMenuDirectory, ContextMenuReadOnlyEntry } from '../context-menu/context-menu.js';

declare const markdownit: ( options?: Record<string, unknown> ) => { render: ( md: string ) => string };

async function typeText( text: string, onPiece: ( piece: string ) => void ): Promise<void>
{
  const THRESHOLD = 6;
  const STEP      = 3;
  const DELAY_MS  = 18;

  if ( text.length <= THRESHOLD ) { onPiece( text ); return; }

  for ( let i = 0; i < text.length; i += STEP )
  {
    onPiece( text.slice( i, i + STEP ) );
    if ( i + STEP < text.length )
      await new Promise<void>( r => setTimeout( r, DELAY_MS ) );
  }
}

function extractRawText( node: Node ): string
{
  if ( node.nodeType === Node.TEXT_NODE ) return node.nodeValue ?? '';
  if ( node.nodeName === 'BR' ) return '\n';
  if ( node.nodeType !== Node.ELEMENT_NODE ) return '';
  let text = '';
  node.childNodes.forEach( child => text += extractRawText( child ) );
  return text;
}

interface RojoEntry { id: string; name: string; description: string; path: string; }

function parentDir( filePath: string ): string
{
  const slash = filePath.lastIndexOf( '/' );
  return slash >= 0 ? filePath.slice( 0, slash ) : 'workspace/rojos';
}

class RojoChatPanel extends HTMLElement
{
  _initialized    = false;
  _conversationId = '';
  _sending        = false;
  _md: { render: ( s: string ) => string } | null = null;
  _rojos: RojoEntry[] = [];
  _selectedPath   = '';

  connectedCallback(): void
  {
    if ( this._initialized ) return;
    this._initialized = true;

    this._conversationId = crypto.randomUUID();
    this._md = markdownit( { html: false, linkify: true, breaks: true } );

    this.className = 'rojo-chat-panel';
    this.innerHTML = `
      <div class="rcp-toolbar">
        <div class="rcp-toolbar-icon">🤖</div>
        <select class="rcp-picker" title="Select Rojo">
          <option value="">— no rojo selected —</option>
        </select>
        <button class="rcp-toolbar-btn rcp-new-btn" title="New Rojo">+</button>
        <button class="rcp-toolbar-btn rcp-refresh-btn" title="Refresh rojo list">↻</button>
      </div>
      <div class="rcp-history"></div>
      <div class="rcp-input-area">
        <div class="rcp-input-text" contenteditable="true"></div>
        <div class="rcp-input-buttons">
          <button class="rcp-input-btn rcp-plus-btn" title="Attach">+</button>
          <button class="rcp-input-btn rcp-send-btn" title="Send">▲</button>
        </div>
      </div>
    `;

    const sendBtn   = this.querySelector( '.rcp-send-btn' ) as HTMLButtonElement;
    const inputText = this.querySelector( '.rcp-input-text' ) as HTMLElement;
    const picker    = this.querySelector( '.rcp-picker' ) as HTMLSelectElement;

    sendBtn.addEventListener( 'click', () => this._send() );

    inputText.addEventListener( 'keydown', ( e: KeyboardEvent ) =>
    {
      if ( e.key === 'Enter' && !e.shiftKey ) { e.preventDefault(); this._send(); }
    } );

    picker.addEventListener( 'change', () =>
    {
      this._selectedPath = picker.value;
    } );

    this.querySelector( '.rcp-new-btn' )!.addEventListener( 'click', () => this._createRojo() );
    this.querySelector( '.rcp-refresh-btn' )!.addEventListener( 'click', () => this._loadRojos() );

    this._loadRojos();
  }

  async _loadRojos(): Promise<void>
  {
    const projectId = Editor.get().projectId;
    if ( !projectId ) return;

    try
    {
      const res = await fetch( `/api/rojos/${ projectId }/list` );
      if ( !res.ok ) return;
      this._rojos = await res.json() as RojoEntry[];
      this._renderPicker();
    }
    catch {}
  }

  _renderPicker(): void
  {
    const picker = this.querySelector( '.rcp-picker' ) as HTMLSelectElement;
    const prev   = this._selectedPath;

    picker.innerHTML = '<option value="">— no rojo selected —</option>' +
      this._rojos.map( r =>
        `<option value="${ r.path }">${ r.name || r.path.slice( r.path.lastIndexOf( '/' ) + 1 ) }</option>`
      ).join( '' );

    if ( prev && this._rojos.some( r => r.path === prev ) )
    {
      picker.value       = prev;
      this._selectedPath = prev;
    }
    else
    {
      this._selectedPath = '';
    }
  }

  async _createRojo(): Promise<void>
  {
    const projectId = Editor.get().projectId;
    if ( !projectId ) return;

    // Place new rojo in the same directory as the currently selected one,
    // or directly in workspace/rojos if nothing is selected.
    const dir = this._selectedPath
      ? parentDir( this._selectedPath )
      : 'workspace/rojos';

    try
    {
      const res = await fetch( `/api/rojos/${ projectId }/create`,
      {
        method:  'POST',
        headers: { 'Content-Type': 'application/json' },
        body:    JSON.stringify( { parentDir: dir } ),
      } );

      if ( !res.ok ) return;
      const { path: newPath } = await res.json() as { id: string; path: string; name: string };

      await this._loadRojos();
      this._selectedPath = newPath;
      ( this.querySelector( '.rcp-picker' ) as HTMLSelectElement ).value = newPath;

      await Editor.get().openDocument( newPath );
    }
    catch {}
  }

  async _send(): Promise<void>
  {
    if ( this._sending ) return;

    const inputText = this.querySelector( '.rcp-input-text' ) as HTMLElement;
    const sendBtn   = this.querySelector( '.rcp-send-btn'   ) as HTMLButtonElement;
    const history   = this.querySelector( '.rcp-history'    ) as HTMLElement;

    const text = extractRawText( inputText ).replaceAll( ' ', ' ' ).trim();
    if ( !text ) return;

    inputText.innerHTML = '';
    this._sending       = true;
    sendBtn.disabled    = true;

    const userBubble     = document.createElement( 'div' );
    userBubble.className = 'rcp-user-bubble';
    userBubble.textContent = text;
    history.appendChild( userBubble );
    history.scrollTop = history.scrollHeight;

    const assistantBubble     = document.createElement( 'div' );
    assistantBubble.className = 'rcp-assistant-bubble';
    assistantBubble.textContent = '…';
    history.appendChild( assistantBubble );
    history.scrollTop = history.scrollHeight;

    try
    {
      const body: Record<string, string> = { id: this._conversationId, message: text };

      if ( this._selectedPath )
      {
        body.projectId = Editor.get().projectId;
        body.rojoPath  = this._selectedPath;
      }

      const response = await fetch( '/api/rojos/chat',
      {
        method:  'POST',
        headers: { 'Content-Type': 'application/json' },
        body:    JSON.stringify( body ),
      } );

      if ( !response.body ) throw new Error( 'No response body' );

      const reader  = response.body.getReader();
      const decoder = new TextDecoder();
      let markdown  = '';

      while ( true )
      {
        const { done, value } = await reader.read();
        if ( done ) break;

        const raw = decoder.decode( value, { stream: true } );

        for ( const line of raw.split( '\n' ) )
        {
          const trimmed = line.trim();
          if ( !trimmed ) continue;

          try
          {
            const msg = JSON.parse( trimmed ) as { type: string; text?: string };
            if ( msg.type === 'CHAT' && msg.text )
            {
              await typeText( msg.text, piece =>
              {
                markdown += piece;
                assistantBubble.innerHTML = this._md!.render( markdown );
                history.scrollTop = history.scrollHeight;
              } );
            }
          }
          catch {}
        }
      }

      if ( !markdown ) assistantBubble.textContent = '(no response)';
    }
    catch ( err )
    {
      assistantBubble.textContent = '(error: could not reach Rojo)';
      console.error( err );
    }

    this._sending    = false;
    sendBtn.disabled = false;
    history.scrollTop = history.scrollHeight;
  }

  addContextMenuEntries( dir: ContextMenuDirectory ): void
  {
    const rojo = this._rojos.find( r => r.path === this._selectedPath );
    dir.add( new ContextMenuReadOnlyEntry( dir, `Rojo: ${ rojo?.name ?? 'none' }` ) );
  }
}

customElements.define( 'rojo-chat-panel', RojoChatPanel );