/**
 * InputOutputDisplay - Displays model inputs and outputs
 * Requirements: 5.1, 5.2, 5.3, 5.4, 5.5, 5.6
 */

class InputOutputDisplay {
  /**
   * @param {string} containerId - ID of the container element
   */
  constructor(containerId) {
    this._containerId = containerId;
    this._container = document.getElementById(containerId);

    if (!this._container) {
      console.warn(`[InputOutputDisplay] Container #${containerId} not found`);
    }
  }

  // ─── Private ──────────────────────────────────────────────────────────────

  /**
   * Escape HTML special characters.
   * @param {string} str
   * @returns {string}
   */
  _escapeHtml(str) {
    const div = document.createElement('div');
    div.appendChild(document.createTextNode(String(str)));
    return div.innerHTML;
  }

  /**
   * Format a tensor shape array to a human-readable string.
   * Dynamic dimensions (negative numbers or strings) are shown as-is.
   * e.g. [1, 3, 224, 224] → "[1, 3, 224, 224]"
   *      [-1, 3, 224, 224] → "[-1, 3, 224, 224]"
   *      ["batch", 3, 224, 224] → "[batch, 3, 224, 224]"
   * @param {Array<number|string>} shape
   * @returns {string}
   */
  _formatShape(shape) {
    if (!shape || shape.length === 0) return '[]';
    const dims = shape.map((d) => {
      if (typeof d === 'string') return d;
      if (d === -1 || d < 0) return 'dynamic';
      return String(d);
    });
    return `[${dims.join(', ')}]`;
  }

  /**
   * Resolve a numeric data type to its string name.
   * @param {number|string} dataType
   * @returns {string}
   */
  _resolveDataType(dataType) {
    if (typeof dataType === 'string') return dataType;
    if (CONFIG && CONFIG.DATA_TYPES && CONFIG.DATA_TYPES[dataType]) {
      return CONFIG.DATA_TYPES[dataType];
    }
    return String(dataType);
  }

  /**
   * Build the HTML for a single tensor entry (input or output).
   * @param {TensorInfo} tensor
   * @param {'input'|'output'} kind
   * @returns {string}
   */
  _buildTensorItem(tensor, kind) {
    const badgeClass = kind === 'input' ? 'bg-primary' : 'bg-success';
    const badgeLabel = kind === 'input' ? 'Input' : 'Output';
    const shape = this._formatShape(tensor.shape);
    const dtype = this._resolveDataType(tensor.dataType);

    return `
      <div class="tensor-item border rounded p-2 mb-2 cursor-pointer"
           role="button"
           tabindex="0"
           data-tensor-name="${this._escapeHtml(tensor.name)}"
           data-kind="${kind}"
           title="Click to highlight in graph"
           aria-label="${this._escapeHtml(tensor.name)} ${badgeLabel}">
        <div class="d-flex align-items-center justify-content-between mb-1">
          <span class="fw-medium text-truncate me-2">${this._escapeHtml(tensor.name)}</span>
          <span class="badge ${badgeClass} flex-shrink-0">${badgeLabel}</span>
        </div>
        <div class="small text-muted">
          <span class="me-3"><i class="fas fa-shapes me-1"></i>${this._escapeHtml(shape)}</span>
          <span><i class="fas fa-tag me-1"></i>${this._escapeHtml(dtype)}</span>
        </div>
        ${tensor.description ? `<div class="small text-secondary mt-1 fst-italic">${this._escapeHtml(tensor.description)}</div>` : ''}
      </div>`;
  }

  /**
   * Attach click (and keyboard) handlers to tensor items.
   */
  _attachItemHandlers() {
    if (!this._container) return;
    const items = this._container.querySelectorAll('.tensor-item');
    items.forEach((item) => {
      const handler = () => {
        const name = item.dataset.tensorName;
        if (name && window.EventBus) {
          window.EventBus.emit(CONFIG.EVENTS.NODE_SELECTED, { nodeId: name, source: 'inputOutput' });
        }
        if (name && window.StateManager) {
          window.StateManager.setSelectedNodeId(name);
        }
      };
      item.addEventListener('click', handler);
      item.addEventListener('keydown', (e) => {
        if (e.key === 'Enter' || e.key === ' ') {
          e.preventDefault();
          handler();
        }
      });
    });
  }

  // ─── Public API ───────────────────────────────────────────────────────────

  /**
   * Render inputs and outputs for a parsed model.
   * @param {ParsedModel} model
   */
  render(model) {
    if (!this._container) return;

    const inputs = (model && model.inputs) ? model.inputs : [];
    const outputs = (model && model.outputs) ? model.outputs : [];

    if (inputs.length === 0 && outputs.length === 0) {
      this._container.innerHTML = '<p class="text-muted">No inputs or outputs found.</p>';
      return;
    }

    let html = '';

    if (inputs.length > 0) {
      html += `<h6 class="text-primary mb-2"><i class="fas fa-arrow-right me-1"></i>Inputs (${inputs.length})</h6>`;
      html += inputs.map((t) => this._buildTensorItem(t, 'input')).join('');
    }

    if (outputs.length > 0) {
      html += `<h6 class="text-success mb-2 ${inputs.length > 0 ? 'mt-3' : ''}"><i class="fas fa-arrow-left me-1"></i>Outputs (${outputs.length})</h6>`;
      html += outputs.map((t) => this._buildTensorItem(t, 'output')).join('');
    }

    this._container.innerHTML = html;
    this._attachItemHandlers();
  }

  /**
   * Clear the display.
   */
  clear() {
    if (!this._container) return;
    this._container.innerHTML = '<p class="text-muted">Select a model to view inputs and outputs</p>';
  }
}

window.InputOutputDisplay = InputOutputDisplay;