import streamlit as st
import hashlib
import pandas as pd
import qrcode
from io import BytesIO
from datetime import datetime
import json
import base64

# Set page config
st.set_page_config(
    page_title="Document Integrity Checker",
    page_icon="🔐",
    layout="wide"
)

# Custom CSS
st.markdown("""
    <style>
        .stApp {
            max-width: 1200px;
            margin: 0 auto;
        }
        .status-success {
            padding: 1rem;
            border-radius: 4px;
            background-color: #dcfce7;
            color: #166534;
        }
        .status-error {
            padding: 1rem;
            border-radius: 4px;
            background-color: #fee2e2;
            color: #991b1b;
        }
        .hash-display {
            font-family: monospace;
            padding: 1rem;
            background-color: #f8fafc;
            border-radius: 4px;
        }
    </style>
""", unsafe_allow_html=True)

def calculate_hash(file_bytes):
    """Calculate SHA-256 hash of file"""
    sha256_hash = hashlib.sha256()
    sha256_hash.update(file_bytes)
    return sha256_hash.hexdigest()

def generate_qr(data):
    """Generate QR code for hash"""
    qr = qrcode.QRCode(version=1, box_size=10, border=5)
    qr.add_data(data)
    qr.make(fit=True)
    img = qr.make_image(fill_color="black", back_color="white")
    
    # Convert to bytes
    buffered = BytesIO()
    img.save(buffered, format="PNG")
    return buffered.getvalue()

def save_to_history(filename, file_hash):
    """Save verification to history"""
    history = json.loads(st.session_state.get('history', '[]'))
    history.insert(0, {
        'filename': filename,
        'hash': file_hash,
        'timestamp': datetime.now().isoformat()
    })
    # Keep only last 10 entries
    history = history[:10]
    st.session_state['history'] = json.dumps(history)

def get_history():
    """Get verification history"""
    try:
        return json.loads(st.session_state.get('history', '[]'))
    except:
        return []

def main():
    # Header
    st.title("🔐 Document Integrity Checker")
    st.markdown("Verifikasi & Lindungi Integritas Dokumen Anda dengan SHA-256")

    # Main content
    col1, col2 = st.columns([2, 1])

    with col1:
        st.subheader("Upload Document")
        uploaded_files = st.file_uploader(
            "Drag and drop files here",
            accept_multiple_files=True,
            type=['pdf', 'doc', 'docx', 'txt', 'jpg', 'png']
        )

        if uploaded_files:
            for uploaded_file in uploaded_files:
                # Calculate hash
                file_bytes = uploaded_file.read()
                file_hash = calculate_hash(file_bytes)

                # Display hash
                st.markdown(f"**File:** {uploaded_file.name}")
                st.markdown(f"""
                    <div class='hash-display'>
                        {file_hash}
                    </div>
                """, unsafe_allow_html=True)

                # Generate and display QR
                qr_code = generate_qr(file_hash)
                st.image(qr_code, caption="Scan untuk verifikasi hash")

                # Save to history
                save_to_history(uploaded_file.name, file_hash)

                # Verification input
                expected_hash = st.text_input("Masukkan hash untuk verifikasi:", key=f"verify_{uploaded_file.name}")
                if expected_hash:
                    if expected_hash.lower() == file_hash.lower():
                        st.markdown("""
                            <div class='status-success'>
                                ✅ Hash cocok! Dokumen terverifikasi.
                            </div>
                        """, unsafe_allow_html=True)
                    else:
                        st.markdown("""
                            <div class='status-error'>
                                ❌ Hash tidak cocok! Dokumen mungkin telah diubah.
                            </div>
                        """, unsafe_allow_html=True)

    with col2:
        st.subheader("Riwayat Verifikasi")
        history = get_history()
        if history:
            for entry in history:
                with st.expander(f"{entry['filename']}"):
                    st.code(entry['hash'], language='text')
                    st.text(f"Verified: {datetime.fromisoformat(entry['timestamp']).strftime('%Y-%m-%d %H:%M:%S')}")
        else:
            st.info("Belum ada riwayat verifikasi")

    # Features explanation
    st.markdown("---")
    feat_col1, feat_col2, feat_col3 = st.columns(3)
    
    with feat_col1:
        st.markdown("### 🚀 Real-time Processing")
        st.markdown("Hasil hash instan saat file diunggah")
    
    with feat_col2:
        st.markdown("### 📁 Multiple Files")
        st.markdown("Proses beberapa file sekaligus")
    
    with feat_col3:
        st.markdown("### 📱 QR Code")
        st.markdown("Share hash dengan mudah via QR")

if __name__ == "__main__":
    main()