"""
app.py  ――――――――――――――――――――――――――――――――――――――――――――――――
✓ Preview · Save · Load 기능 포함
✓ Load 시 노드/좌표/엣지 자동 복원
✓ 동적 렌더링으로 기존 WorkflowBuilder 업데이트
"""

import os, json, typing, tempfile
import gradio as gr
from gradio_workflowbuilder import WorkflowBuilder

# -------------------------------------------------------------------
# 🛠️  헬퍼
# -------------------------------------------------------------------
def export_pretty(data: typing.Dict[str, typing.Any]) -> str:
    return json.dumps(data, indent=2, ensure_ascii=False) if data else "No workflow to export"

def export_file(data: typing.Dict[str, typing.Any]) -> typing.Optional[str]:
    if not data:
        return None
    fd, path = tempfile.mkstemp(suffix=".json")
    with os.fdopen(fd, "w", encoding="utf-8") as f:
        json.dump(data, f, ensure_ascii=False, indent=2)
    return path

def load_json_file(file_obj):
    """JSON 파일 읽기"""
    if file_obj is None:
        return None, "No file selected"
    
    try:
        with open(file_obj.name, "r", encoding="utf-8") as f:
            data = json.load(f)
        
        # 데이터 검증
        if not isinstance(data, dict):
            return None, "Invalid format: not a dictionary"
        
        # 필수 필드 확인
        if 'nodes' not in data:
            data['nodes'] = []
        if 'edges' not in data:
            data['edges'] = []
            
        nodes_count = len(data.get('nodes', []))
        edges_count = len(data.get('edges', []))
        
        return data, f"✅ Loaded: {nodes_count} nodes, {edges_count} edges"
        
    except Exception as e:
        return None, f"❌ Error: {str(e)}"

def create_sample_workflow():
    """샘플 워크플로우 생성"""
    return {
        "nodes": [
            {
                "id": "node_1",
                "type": "default",
                "position": {"x": 100, "y": 100},
                "data": {"label": "Start Node"}
            },
            {
                "id": "node_2",
                "type": "default",
                "position": {"x": 300, "y": 100},
                "data": {"label": "Process"}
            },
            {
                "id": "node_3",
                "type": "default",
                "position": {"x": 500, "y": 100},
                "data": {"label": "End Node"}
            }
        ],
        "edges": [
            {
                "id": "edge_1",
                "source": "node_1",
                "target": "node_2"
            },
            {
                "id": "edge_2",
                "source": "node_2",
                "target": "node_3"
            }
        ]
    }

# -------------------------------------------------------------------
# 🎨 CSS
# -------------------------------------------------------------------
CSS = """
.main-container{max-width:1600px;margin:0 auto;}
.workflow-section{margin-bottom:2rem;min-height:500px;}
.button-row{display:flex;gap:1rem;justify-content:center;margin:1rem 0;}
.status-box{
    padding:10px;border-radius:5px;margin-top:10px;
    background:#f0f9ff;border:1px solid #3b82f6;color:#1e40af;
}
.component-description{
  padding:24px;background:linear-gradient(135deg,#f8fafc 0%,#e2e8f0 100%);
  border-left:4px solid #3b82f6;border-radius:12px;
  box-shadow:0 2px 8px rgba(0,0,0,.05);margin:16px 0;
}
.workflow-container{position:relative;}
"""

# -------------------------------------------------------------------
# 🖥️  Gradio 앱
# -------------------------------------------------------------------
with gr.Blocks(title="🎨 Visual Workflow Builder", theme=gr.themes.Soft(), css=CSS) as demo:
    
    with gr.Column(elem_classes=["main-container"]):
        gr.Markdown("# 🎨 Visual Workflow Builder\n**Create sophisticated workflows with drag-and-drop simplicity.**")
        
        gr.HTML(
            """
            <div class="component-description">
              <p style="font-size:16px;margin:0;">Powered by <strong>svelteflow</strong> • Create custom workflows</p>
            </div>
            """
        )
        
        # State for storing loaded data
        loaded_data = gr.State(None)
        trigger_update = gr.State(False)
        
        # ─── Dynamic Workflow Container ───
        with gr.Column(elem_classes=["workflow-container"]):
            @gr.render(inputs=[loaded_data, trigger_update])
            def render_workflow(data, trigger):
                """동적으로 WorkflowBuilder 렌더링"""
                workflow_value = data if data else {"nodes": [], "edges": []}
                
                return WorkflowBuilder(
                    label="🎨 Visual Workflow Designer",
                    info="Drag from output ➜ input • Click nodes to edit properties",
                    value=workflow_value,
                    elem_id="main_workflow"
                )
        
        # ─── Control Panel ───
        gr.Markdown("## 💾 Export · 📂 Import")
        
        with gr.Row(elem_classes=["button-row"]):
            with gr.Column(scale=2):
                file_upload = gr.File(
                    label="📂 Select JSON file",
                    file_types=[".json"],
                    type="filepath"
                )
            with gr.Column(scale=1):
                btn_load = gr.Button("📥 Load Workflow", variant="primary", size="lg")
                btn_sample = gr.Button("🎯 Load Sample", variant="secondary")
        
        with gr.Row(elem_classes=["button-row"]):
            btn_preview = gr.Button("👁️ Preview JSON")
            btn_download = gr.DownloadButton("💾 Download JSON")
            btn_reset = gr.Button("🔄 Reset", variant="stop")
        
        # Status
        status_text = gr.Textbox(
            label="Status", 
            value="Ready", 
            elem_classes=["status-box"],
            interactive=False
        )
        
        # Code View
        code_view = gr.Code(
            language="json", 
            label="JSON Preview", 
            lines=10,
            visible=False
        )
        
        btn_toggle_code = gr.Button("📋 Toggle Code View", size="sm")
        
        # ─── Event Handlers ───
        
        # File upload → Store data
        file_upload.change(
            fn=load_json_file,
            inputs=file_upload,
            outputs=[loaded_data, status_text]
        )
        
        # Load button → Trigger render update
        btn_load.click(
            fn=lambda current_trigger: not current_trigger,
            inputs=trigger_update,
            outputs=trigger_update
        )
        
        # Sample workflow
        btn_sample.click(
            fn=lambda: (create_sample_workflow(), "✅ Sample loaded"),
            outputs=[loaded_data, status_text]
        ).then(
            fn=lambda current_trigger: not current_trigger,
            inputs=trigger_update,
            outputs=trigger_update
        )
        
        # Reset
        btn_reset.click(
            fn=lambda: ({"nodes": [], "edges": []}, "✅ Reset complete"),
            outputs=[loaded_data, status_text]
        ).then(
            fn=lambda current_trigger: not current_trigger,
            inputs=trigger_update,
            outputs=trigger_update
        )
        
        # Toggle code view
        btn_toggle_code.click(
            fn=lambda visible: gr.update(visible=not visible),
            inputs=code_view,
            outputs=code_view
        )
        
        # Preview - 현재 워크플로우를 가져와서 표시
        btn_preview.click(
            fn=lambda data: (gr.update(visible=True), export_pretty(data)),
            inputs=loaded_data,
            outputs=[code_view, code_view]
        )
        
        # Download - loaded_data를 파일로 내보내기
        btn_download.click(
            fn=export_file,
            inputs=loaded_data
        )
        
        # ─── Instructions ───
        with gr.Accordion("📖 How to Use", open=False):
            gr.Markdown(
                """
### 🚀 Quick Start
1. **Create** — Add nodes and connect them in the workflow designer
2. **Save** — Click "Download JSON" to save your workflow
3. **Load** — Select a JSON file and click "Load Workflow"

### 📝 Workflow Format
```json
{
  "nodes": [
    {
      "id": "unique_id",
      "type": "default",
      "position": {"x": 100, "y": 100},
      "data": {"label": "Node Name"}
    }
  ],
  "edges": [
    {
      "id": "edge_id",
      "source": "source_node_id",
      "target": "target_node_id"
    }
  ]
}
```

### 💡 Tips
- The workflow will automatically update when you load a file
- Use "Load Sample" to see an example workflow
- Toggle code view to see the JSON structure
                """
            )

# -------------------------------------------------------------------
# 🚀 실행
# -------------------------------------------------------------------
if __name__ == "__main__":
    demo.launch(server_name="0.0.0.0", show_error=True)