import gradio as gr
import hashlib
from typing import List, Dict, Tuple
import os
import time

from document_processor.file_handler import DocumentProcessor
from retriever.builder import RetrieverBuilder
from agents.workflow import AgentWorkflow
from config import constants, settings
from utils.logging import logger


def main():
    processor = DocumentProcessor()
    retriever_builder = RetrieverBuilder()
    workflow = AgentWorkflow()

    # Define custom CSS for ChatGPT-like styling with dark sidebar
    css = """
    .sidebar {
        background: #202123 !important;
        border-right: 1px solid #343541 !important;
        max-height: 90vh !important;
        height: auto !important;
        overflow-y: auto !important;
        padding: 15px !important;
        color: #ffffff !important;
    }
    
    .sidebar * {
        color: #ffffff !important;
    }
    
    .sidebar label {
        color: #d1d5db !important;
    }
    
    .sidebar input, .sidebar select, .sidebar textarea {
        background: #343541 !important;
        color: #ffffff !important;
        border: 1px solid #565869 !important;
    }
    
    .main-container {
        max-height: 90vh !important;
        height: auto !important;
        overflow-yL: auto !important;
    }
    
    .chat-area {
        height: 100vh !important;
        display: flex !important;
        flex-direction: column !important;
        padding: 10px !important;
    }
    
    .chatbot-container {
        flex: 1 1 auto !important;
        min-height: 300px !important;
        max-height: calc(100vh - 280px) !important;
        overflow: hidden !important;
    }
    
    .chatbot-container .gradio-chatbot {
        height: 100% !important;
        max-height: calc(100vh - 280px) !important;
    }
    
    .input-area {
        margin-top: 10px !important;
    }
    
    .processing-status {
        padding: 8px !important;
        border-radius: 6px !important;
        margin: 8px 0 !important;
        font-size: 0.9em !important;
    }
    
    .success {
        background: #d4edda !important;
        color: #155724 !important;
        border: 1px solid #c3e6cb !important;
    }
    
    .error {
        background: #f8d7da !important;
        color: #721c24 !important;
        border: 1px solid #f5c6cb !important;
    }
    
    .progress-info {
        font-size: 0.85em !important;
        color: #666 !important;
        margin-top: 5px !important;
    }
    """

    with gr.Blocks(theme=gr.themes.Soft(), title="DocChat", css=css) as demo:
        # Session state for document processing
        session_state = gr.State({
            "file_hashes": frozenset(),
            "retriever": None,
            "processed_files": [],
            "chat_history": []
        })

        # Main layout: Sidebar + Chat
        with gr.Row(equal_height=True, elem_classes="main-container"):
            # Left Sidebar for file management (narrower)
            with gr.Column(scale=0.7, min_width=250, elem_classes="sidebar"):
                gr.Markdown("## 📁 Upload your documents here", elem_classes="title")
                
                # File upload component - files shown here
                files = gr.Files(
                    label="Upload Documents",
                    file_types=constants.ALLOWED_TYPES,
                    height=150,
                    show_label=True
                )
                
                # Sync button and status
                with gr.Row():
                    sync_btn = gr.Button("🔄 Sync", variant="primary", scale=1, size="sm", elem_classes=["flex-item"])
                with gr.Row():
                    sync_status_indicator = gr.HTML(
                        '<div style="padding: 6px; text-align: center; border-radius: 4px; background: #343541; color: #9ca3af; font-size: 0.85em; width: 100%;">Not synced</div>',
                        visible=True,
                        elem_classes=["flex-item"]
                    )
                # Provide equal layout using some CSS tweaks
                gr.HTML("""
                <style>
                    .svelte-1ipelgc.flex-item { flex: 1 1 0 !important; min-width: 0 !important; }
                </style>
                """)
                
                # Processing status (only show when processing/processed)
                processing_status = gr.Markdown("", elem_classes="processing-status", visible=False)
                
                # Verification Report Section
                gr.HTML("""
                    <style>
                    .compact-markdown p, 
                    .compact-markdown h4, 
                    .compact-markdown h5, 
                    .compact-markdown h6 {
                        margin-top: 0.25rem !important;
                        margin-bottom: 0.25rem !important;
                    }
                    </style>
                    """)

                # gr.Markdown("---")
                gr.Markdown('<span style="font-size: 1em;">📊 Verification Report</span>', elem_classes="compact-markdown")
                # gr.Markdown('<span style="font-size: 0.85em; color: #8e9297;"><em>Of the last message</em></span>', elem_classes="compact-markdown")
                verification_output = gr.Textbox(
                    label="",
                    interactive=False,
                    lines=12,
                    max_lines=12,
                    value="",
                    placeholder="""### Verification Report""",
                    show_label=False
                )
            
            # Right side: Chat interface
            with gr.Column(scale=4, elem_classes="chat-area"):
                # Header section
                gr.Markdown("# 🤖 GeekBot *Your personal AI*")
                gr.Markdown("*Enter your documents and start chatting about it. Supports ppt,pdf,txt, etc*")
                
                # Chat interface - flex to fill available space
                with gr.Column(elem_classes="chatbot-container"):
                    chatbot = gr.Chatbot(
                        label="",
                        show_label=False,
                        show_copy_button=True,
                        avatar_images=(None, "🤖"),
                        container=True,
                        height=550
                    )
                
                # Input area
                with gr.Row(elem_classes="input-area"):
                    msg = gr.Textbox(
                        label="",
                        placeholder="Type your question here...",
                        show_label=False,
                        scale=9,
                        container=False
                    )
                    submit_btn = gr.Button("Send", scale=1, variant="primary")
        
        # Function to remove files from ChromaDB when they're removed from UI
        def handle_file_removal(current_files: List, state: Dict):
            """Handle file removal - clean up ChromaDB and retriever if files are removed."""
            if not current_files:
                # All files removed - reset retriever
                if state.get("retriever"):
                    logger.info("All files removed. Resetting retriever.")
                    state.update({
                        "retriever": None,
                        "file_hashes": frozenset(),
                        "processed_files": []
                    })
                    return (
                        get_sync_status_html("ready"),
                        "",  # processing_status
                        gr.update(visible=False),  # processing_status visibility
                        state
                    )
                return (
                    get_sync_status_html("ready"),
                    "",
                    gr.update(visible=False),
                    state
                )
            
            # Check if any files were removed
            current_hashes = _get_file_hashes(current_files)
            if state.get("file_hashes") and current_hashes != state["file_hashes"]:
                # Files were removed - need to rebuild retriever with remaining files
                logger.info("Files were removed. Rebuilding retriever with remaining files...")
                try:
                    chunks = processor.process(current_files)
                    retriever = retriever_builder.build_hybrid_retriever(chunks)
                    
                    state.update({
                        "file_hashes": current_hashes,
                        "retriever": retriever,
                        "processed_files": current_files
                    })
                    
                    status_html = "✅ **Documents resynced**<br>"
                    status_html += f"<div class='progress-info'>{len(chunks)} chunks indexed.</div>"
                    
                    return (
                        get_sync_status_html("synced", len(chunks)),
                        status_html,
                        gr.update(visible=True),
                        state
                    )
                except Exception as e:
                    logger.error(f"Error resyncing after file removal: {e}")
                    return (
                        get_sync_status_html("error"),
                        f"❌ Error: {str(e)}",
                        gr.update(visible=True),
                        state
                    )
            
            return (
                get_sync_status_html("synced", len(state.get("processed_files", []))),
                "",
                gr.update(visible=False),
                state
            )

        # Function to update sync status indicator
        def get_sync_status_html(status: str, count: int = 0) -> str:
            """Generate HTML for sync status indicator."""
            if status == "synced":
                return f'<div style="padding: 8px; text-align: center; border-radius: 4px; background: #16a34a; color: #ffffff; font-weight: bold;">✅ Synced ({count} chunks)</div>'
            elif status == "syncing":
                return '<div style="padding: 8px; text-align: center; border-radius: 4px; background: #f59e0b; color: #ffffff; font-weight: bold;">🔄 Syncing...</div>'
            elif status == "error":
                return '<div style="padding: 8px; text-align: center; border-radius: 4px; background: #dc2626; color: #ffffff; font-weight: bold;">❌ Error</div>'
            else:
                return '<div style="padding: 8px; text-align: center; border-radius: 4px; background: #343541; color: #9ca3af;">Not synced</div>'
        
        # Function to process files (called by sync button)
        def process_files(uploaded_files: List, state: Dict):
            """Process files and build retriever."""
            if not uploaded_files:
                return (
                    get_sync_status_html("ready"),  # sync_status
                    "",  # processing_status
                    gr.update(visible=False),  # processing_status visibility
                    state
                )
            
            try:
                current_hashes = _get_file_hashes(uploaded_files)
                
                # Check if files are new or changed
                if state["retriever"] is None or current_hashes != state["file_hashes"]:
                    # Process documents
                    logger.info("Processing new/changed documents...")
                    chunks = processor.process(uploaded_files)
                    logger.info("Building retriever...")
                    retriever = retriever_builder.build_hybrid_retriever(chunks)
                    logger.info("Retriever built successfully")
                    
                    state.update({
                        "file_hashes": current_hashes,
                        "retriever": retriever,
                        "processed_files": uploaded_files
                    })
                    
                    status_html = "✅ **Documents synced successfully!**<br>"
                    status_html += f"<div class='progress-info'>{len(chunks)} chunks indexed. Ready for questions!</div>"
                    
                    return (
                        get_sync_status_html("synced", len(chunks)),  # sync_status
                        status_html,  # processing_status
                        gr.update(visible=True),  # processing_status visibility
                        state
                    )
                else:
                    # Files unchanged, already synced
                    status_html = "✅ **Documents already synced**<br>"
                    status_html += "<div class='progress-info'>Files are up to date. Ready for questions!</div>"
                    
                    # Get chunk count from state if available
                    chunk_count = len(state.get("processed_files", []))
                    
                    return (
                        get_sync_status_html("synced", chunk_count),  # sync_status
                        status_html,  # processing_status
                        gr.update(visible=True),  # processing_status visibility
                        state
                    )
            except Exception as e:
                error_html = f"❌ **Error syncing documents**<br>"
                error_html += f"<div class='progress-info'>{str(e)}</div>"
                logger.error(f"File processing error: {str(e)}")
                
                return (
                    get_sync_status_html("error"),  # sync_status
                    error_html,  # processing_status
                    gr.update(visible=True),  # processing_status visibility
                    state
                )
        

        # Chat function for handling questions
        def chat_function(message: str, history: List, state: Dict, verification_state: str):
            """Handle chat messages and generate responses."""
            try:
                if not message.strip():
                    history.append((message, "Please enter a question."))
                    return history, "", state, verification_state
                
                if state["retriever"] is None:
                    history.append((message, "❌ No documents uploaded. Please upload documents first."))
                    return history, "", state, verification_state
                
                # Get answer from workflow
                result = workflow.full_pipeline(
                    question=message,
                    retriever=state["retriever"]
                )
                
                answer = result["draft_answer"]
                verification_report = result["verification_report"]
                
                # Add to chat history
                history.append((message, answer))
                
                # Update state
                if "chat_history" not in state:
                    state["chat_history"] = []
                state["chat_history"].append({"question": message, "answer": answer})
                
                return history, "", state, verification_report
                    
            except Exception as e:
                logger.error(f"Chat error: {str(e)}")
                error_msg = f"❌ Error: {str(e)}"
                history.append((message, error_msg))
                return history, "", state, ""
        
        # Event handlers
        # Handle file removal - check when files change
        files.change(
            fn=handle_file_removal,
            inputs=[files, session_state],
            outputs=[sync_status_indicator, processing_status, processing_status, session_state]
        )
        
        # Sync button to process files
        sync_btn.click(
            fn=process_files,
            inputs=[files, session_state],
            outputs=[sync_status_indicator, processing_status, processing_status, session_state],
            show_progress=True
        )
        
        # Chat submission
        msg.submit(
            fn=chat_function,
            inputs=[msg, chatbot, session_state, verification_output],
            outputs=[chatbot, msg, session_state, verification_output]
        )
        
        submit_btn.click(
            fn=chat_function,
            inputs=[msg, chatbot, session_state, verification_output],
            outputs=[chatbot, msg, session_state, verification_output]
        )

    # demo.launch(server_name="127.0.0.1", server_port=5000, share=True)
    return demo

def _get_file_hashes(uploaded_files: List) -> frozenset:
    """Generate SHA-256 hashes for uploaded files."""
    hashes = set()
    for file in uploaded_files:
        # Handle both Gradio file objects and string paths
        file_path = file.name if hasattr(file, 'name') else file
        try:
            with open(file_path, "rb") as f:
                hashes.add(hashlib.sha256(f.read()).hexdigest())
        except Exception as e:
            logger.error(f"Error hashing file {file_path}: {e}")
            continue
    return frozenset(hashes)

if __name__ == "__main__":
    main().launch()