# Page Layouts Feature

## Overview

The Page Layouts feature allows administrators to customize how fields are displayed in detail and edit views using a visual drag-and-drop interface based on GridStack.js with a 6-column grid system.

## Architecture

### Backend Components

1. **Database Schema** (`migrations/tenant/20250126000008_create_page_layouts.js`)
   - `page_layouts` table stores layout configurations
   - Fields: `id`, `name`, `object_id`, `is_default`, `layout_config`, `description`
   - JSON-based `layout_config` stores field positions and sizes

2. **API Endpoints** (`src/page-layout/`)
   - `POST /page-layouts` - Create a new page layout
   - `GET /page-layouts?objectId={id}` - Get all layouts for an object
   - `GET /page-layouts/:id` - Get a specific layout
   - `GET /page-layouts/default/:objectId` - Get the default layout for an object
   - `PATCH /page-layouts/:id` - Update a layout
   - `DELETE /page-layouts/:id` - Delete a layout

### Frontend Components

1. **PageLayoutEditor.vue** - Visual editor for creating/editing layouts
   - 6-column grid system using GridStack.js
   - Drag and drop fields from sidebar
   - Resize fields horizontally (1-6 columns width)
   - Default width: 3 columns (2-column template effect)
   - Save layout configuration

2. **PageLayoutRenderer.vue** - Renders fields based on saved layouts
   - Used in detail and edit views
   - Falls back to traditional 2-column layout if no layout configured
   - Supports all field types

3. **DetailViewEnhanced.vue** & **EditViewEnhanced.vue**
   - Enhanced versions of views with page layout support
   - Automatically fetch and use default page layout
   - Maintain backward compatibility with section-based layouts

### Types

- **PageLayout** (`types/page-layout.ts`)
  - Layout metadata and configuration
  - Field position and size definitions
  - Grid configuration options

## Usage

### 1. Run Database Migration

```bash
cd backend
npm run migrate:tenant
```

### 2. Configure Page Layouts

Navigate to **Setup → Objects → [Object Name] → Page Layouts** tab:

1. Click "New Layout" to create a layout
2. Enter a layout name
3. Drag fields from the right sidebar onto the 6-column grid
4. Resize fields by dragging their edges (width only)
5. Rearrange fields by dragging them to new positions
6. Click "Save Layout" to persist changes

### 3. Use in Views

#### Option A: Use Enhanced Views (Recommended)

Replace existing views in your page:

```vue
<script setup>
import DetailViewEnhanced from '@/components/views/DetailViewEnhanced.vue'
import EditViewEnhanced from '@/components/views/EditViewEnhanced.vue'

const objectDefinition = ref(null)

// Fetch object definition...
</script>

<template>
  <!-- Detail View -->
  <DetailViewEnhanced
    :config="detailConfig"
    :data="currentRecord"
    :object-id="objectDefinition.id"
    @edit="handleEdit"
    @delete="handleDelete"
    @back="handleBack"
  />

  <!-- Edit View -->
  <EditViewEnhanced
    :config="editConfig"
    :data="currentRecord"
    :object-id="objectDefinition.id"
    @save="handleSave"
    @cancel="handleCancel"
    @back="handleBack"
  />
</template>
```

#### Option B: Use PageLayoutRenderer Directly

```vue
<script setup>
import PageLayoutRenderer from '@/components/PageLayoutRenderer.vue'
import { usePageLayouts } from '~/composables/usePageLayouts'

const { getDefaultPageLayout } = usePageLayouts()
const pageLayout = ref(null)

onMounted(async () => {
  const layout = await getDefaultPageLayout(objectId)
  if (layout) {
    pageLayout.value = layout.layoutConfig
  }
})
</script>

<template>
  <PageLayoutRenderer
    :fields="fields"
    :layout="pageLayout"
    :model-value="formData"
    :readonly="false"
    @update:model-value="formData = $event"
  />
</template>
```

### 4. Composable API

```typescript
const { 
  getPageLayouts,       // Get all layouts for an object
  getPageLayout,        // Get a specific layout
  getDefaultPageLayout, // Get default layout for an object
  createPageLayout,     // Create new layout
  updatePageLayout,     // Update existing layout
  deletePageLayout      // Delete layout
} = usePageLayouts()

// Example: Create a layout
await createPageLayout({
  name: 'Sales Layout',
  objectId: 'uuid-here',
  isDefault: true,
  layoutConfig: {
    fields: [
      { fieldId: 'field-1', x: 0, y: 0, w: 3, h: 1 },
      { fieldId: 'field-2', x: 3, y: 0, w: 3, h: 1 },
    ]
  }
})
```

## Grid System

### Configuration
- **Columns**: 6
- **Default field width**: 3 columns (50% width)
- **Min width**: 1 column (16.67%)
- **Max width**: 6 columns (100%)
- **Height**: Fixed at 1 unit (80px), uniform across all fields

### Layout Example

```
┌─────────────────────┬─────────────────────┐
│   Field 1 (w:3)     │   Field 2 (w:3)     │  ← Two 3-column fields
├─────────────────────┴─────────────────────┤
│          Field 3 (w:6)                     │  ← One full-width field
├──────────┬──────────┬──────────┬──────────┤
│ F4 (w:2) │ F5 (w:2) │ F6 (w:2) │ (empty)  │  ← Three 2-column fields
└──────────┴──────────┴──────────┴──────────┘
```

## Features

### Editor
- ✅ 6-column responsive grid
- ✅ Drag fields from sidebar to grid
- ✅ Drag to reposition fields on grid
- ✅ Resize fields horizontally (1-6 columns)
- ✅ Remove fields from layout
- ✅ Save layout configuration
- ✅ Clear all fields

### Renderer
- ✅ Renders fields based on saved layout
- ✅ Respects field positioning and sizing
- ✅ Supports all field types
- ✅ Falls back to 2-column layout if no layout configured
- ✅ Works in both readonly (detail) and edit modes

### Layout Management
- ✅ Multiple layouts per object
- ✅ Default layout designation
- ✅ Create, read, update, delete layouts
- ✅ Tab-based interface in object setup

## Backward Compatibility

The system maintains full backward compatibility:
- Objects without page layouts use traditional section-based views
- Existing DetailView and EditView components continue to work
- Enhanced views automatically detect and use page layouts when available

## Technical Details

### Layout Storage Format

```json
{
  "fields": [
    {
      "fieldId": "uuid-of-field",
      "x": 0,        // Column start (0-5)
      "y": 0,        // Row start (0-based)
      "w": 3,        // Width in columns (1-6)
      "h": 1         // Height in rows (fixed at 1)
    }
  ]
}
```

### Field Component Mapping

The renderer automatically maps field types to appropriate components:
- TEXT → TextFieldView
- NUMBER → NumberFieldView
- DATE/DATETIME → DateFieldView
- BOOLEAN → BooleanFieldView
- PICKLIST → SelectFieldView
- EMAIL → EmailFieldView
- PHONE → PhoneFieldView
- URL → UrlFieldView
- CURRENCY → CurrencyFieldView
- PERCENT → PercentFieldView
- TEXTAREA → TextareaFieldView

## Development

### Adding New Field Types

1. Create field view component in `components/fields/`
2. Add mapping in `PageLayoutRenderer.vue`:

```typescript
const componentMap: Record<string, any> = {
  // ... existing mappings
  NEW_TYPE: NewFieldView,
}
```

### Customizing Grid Settings

Edit `PageLayoutEditor.vue`:

```typescript
grid = GridStack.init({
  column: 6,          // Change column count
  cellHeight: 80,     // Change cell height
  minRow: 1,          // Minimum rows
  float: true,        // Allow floating
  acceptWidgets: true,
  animate: true,
})
```

## Troubleshooting

### Layout not appearing
- Ensure migration has been run
- Check that a default layout is set
- Verify objectId is passed to enhanced views

### Fields not draggable
- Check GridStack CSS is loaded
- Verify draggable attribute on sidebar fields
- Check browser console for errors

### Layout not saving
- Verify API endpoints are accessible
- Check authentication token
- Review backend logs for errors

## Future Enhancements

- [ ] Variable field heights
- [ ] Field-level permissions in layouts
- [ ] Clone/duplicate layouts
- [ ] Layout templates
- [ ] Layout preview mode
- [ ] Responsive breakpoints
- [ ] Related list sections
- [ ] Custom components in layouts