import { LitElement, html, css } from './plugins.js';
import type { CSSResult, TemplateResult, ChatSession, IAgentRunResult } from './plugins.js';
import './smartchat-message.js';
import './smartchat-input.js';

interface IDisplayMessage {
  role: 'user' | 'assistant' | 'tool';
  content: string;
  toolName?: string;
}

export class SmartchatWindow extends LitElement {
  declare chatSession: ChatSession;
  declare placeholder: string;
  private messages: IDisplayMessage[] = [];
  private busy = false;
  private streamingText = '';

  static properties = {
    chatSession: { attribute: false },
    placeholder: { type: String },
  };

  static styles: CSSResult = css`
    :host {
      display: flex;
      flex-direction: column;
      height: 100%;
      background: var(--smartchat-bg, #111827);
      color: var(--smartchat-text, #e5e7eb);
      font-family: var(--smartchat-font, system-ui, -apple-system, sans-serif);
      border-radius: var(--smartchat-radius, 12px);
      overflow: hidden;
    }

    .message-list {
      flex: 1;
      overflow-y: auto;
      padding: 16px;
      display: flex;
      flex-direction: column;
      gap: 4px;
    }

    .empty-state {
      display: flex;
      align-items: center;
      justify-content: center;
      flex: 1;
      color: var(--smartchat-muted, #6b7280);
      font-size: 14px;
    }

    .streaming {
      padding: 8px 12px;
      background: var(--smartchat-assistant-bubble, #374151);
      color: var(--smartchat-assistant-text, #e5e7eb);
      border-radius: 8px;
      border-bottom-left-radius: 2px;
      max-width: 85%;
      white-space: pre-wrap;
    }

    .cursor {
      display: inline-block;
      width: 2px;
      height: 1em;
      background: var(--smartchat-cursor, #6366f1);
      animation: blink 1s step-end infinite;
      vertical-align: text-bottom;
    }

    @keyframes blink {
      50% { opacity: 0; }
    }

    .input-area {
      padding: 12px 16px;
      border-top: 1px solid var(--smartchat-border, #1f2937);
    }
  `;

  constructor() {
    super();
    this.placeholder = 'Type a message...';
  }

  connectedCallback() {
    super.connectedCallback();
    if (this.chatSession) {
      this.chatSession.updateCallbacks({
        onToken: (delta: string) => {
          this.streamingText += delta;
          this.requestUpdate();
          this.scrollToBottom();
        },
        onToolCall: (name: string) => {
          this.messages = [
            ...this.messages,
            { role: 'tool', content: '', toolName: name },
          ];
          this.requestUpdate();
          this.scrollToBottom();
        },
      });
    }
  }

  private scrollToBottom() {
    requestAnimationFrame(() => {
      const list = this.shadowRoot?.querySelector('.message-list');
      if (list) {
        list.scrollTop = list.scrollHeight;
      }
    });
  }

  private async handleSend(e: CustomEvent<{ text: string }>) {
    if (this.busy) return;

    const text = e.detail.text;
    this.messages = [...this.messages, { role: 'user', content: text }];
    this.busy = true;
    this.streamingText = '';
    this.requestUpdate();
    this.scrollToBottom();

    try {
      const result = await this.chatSession.send(text);
      this.streamingText = '';
      this.messages = [...this.messages, { role: 'assistant', content: result.text }];
    } catch (error) {
      const errMsg = error instanceof Error ? error.message : String(error);
      this.messages = [
        ...this.messages,
        { role: 'assistant', content: `Error: ${errMsg}` },
      ];
    } finally {
      this.busy = false;
      this.requestUpdate();
      this.scrollToBottom();
    }
  }

  render(): TemplateResult {
    return html`
      <div class="message-list">
        ${this.messages.length === 0 && !this.busy
          ? html`<div class="empty-state">Start a conversation...</div>`
          : ''}
        ${this.messages.map(
          (msg) => html`
            <smartchat-message
              role=${msg.role}
              content=${msg.content}
              .toolName=${msg.toolName ?? ''}
            ></smartchat-message>
          `,
        )}
        ${this.busy && this.streamingText
          ? html`
              <div class="streaming">
                ${this.streamingText}<span class="cursor"></span>
              </div>
            `
          : ''}
      </div>
      <div class="input-area">
        <smartchat-input
          ?disabled=${this.busy}
          placeholder=${this.placeholder}
          @send=${this.handleSend}
        ></smartchat-input>
      </div>
    `;
  }
}

customElements.define('smartchat-window', SmartchatWindow);