Create app.py

app.py

@@ -0,0 +1,163 @@
+import streamlit as st
+import json
+import hashlib
+from web3 import Web3
+from google import genai
+from google.genai import types
+
+# --------------------------------------------------
+# PAGE CONFIG
+# --------------------------------------------------
+st.set_page_config(
+    page_title="Invoice-Flow AI",
+    layout="wide",
+    initial_sidebar_state="collapsed"
+)
+
+st.title("📄 Invoice-Flow AI")
+st.markdown("### Agentic invoice verification & on-chain trust registry")
+
+# --------------------------------------------------
+# SECRETS (HF SAFE)
+# --------------------------------------------------
+try:
+    GEMINI_API_KEY = st.secrets["GEMINI_API_KEY"]
+    RPC_URL = st.secrets["RPC_URL"]
+    PRIVATE_KEY = st.secrets["PRIVATE_KEY"]
+except Exception:
+    st.error("🚨 Secrets missing. Add them in Hugging Face → Settings → Variables.")
+    st.stop()
+
+# --------------------------------------------------
+# CLIENT SETUP
+# --------------------------------------------------
+try:
+    genai_client = genai.Client(api_key=GEMINI_API_KEY)
+
+    w3 = Web3(Web3.HTTPProvider(RPC_URL))
+    account = w3.eth.account.from_key(PRIVATE_KEY)
+
+    CONTRACT_ADDRESS = "0x3af7C33f4D0303E6eb94c2D24fB0bD82B54c6914"
+    checksum_address = Web3.to_checksum_address(CONTRACT_ADDRESS)
+
+    with open("abi.json", "r") as f:
+        ABI = json.load(f)
+
+    contract = w3.eth.contract(address=checksum_address, abi=ABI)
+
+except Exception as e:
+    st.error(f"Setup failed: {e}")
+    st.stop()
+
+# --------------------------------------------------
+# UTIL
+# --------------------------------------------------
+def get_mock_invoice():
+    return {
+        "seller_name": "TechFlow Solutions Pvt Ltd",
+        "seller_gstin": "29AAACF5724R1Z5",
+        "invoice_amount": 75000,
+        "invoice_number": "INV-2024-001"
+    }
+
+# --------------------------------------------------
+# SESSION STATE
+# --------------------------------------------------
+for key, value in {
+    "invoice": None,
+    "approved": False,
+    "minted": False,
+    "tx_hash": None
+}.items():
+    if key not in st.session_state:
+        st.session_state[key] = value
+
+# --------------------------------------------------
+# UI
+# --------------------------------------------------
+col1, col2 = st.columns([1, 1])
+
+with col1:
+    st.subheader("1️⃣ Upload & Analyze Invoice")
+    uploaded = st.file_uploader("Upload Invoice (PDF)", type=["pdf"])
+
+    if uploaded:
+        pdf_bytes = uploaded.getvalue()
+
+        if st.button("🚀 Analyze with Gemini 1.5 Flash"):
+            with st.spinner("Extracting invoice data..."):
+                try:
+                    response = genai_client.models.generate_content(
+                        model="gemini-1.5-flash",
+                        contents=[
+                            types.Part.from_bytes(pdf_bytes, "application/pdf"),
+                            "Extract invoice as JSON with keys: seller_name, seller_gstin, invoice_amount, invoice_number. Return ONLY raw JSON."
+                        ]
+                    )
+
+                    text = response.text.replace("```json", "").replace("```", "").strip()
+                    st.session_state.invoice = json.loads(text)
+
+                except Exception as e:
+                    st.warning(f"AI parsing failed ({e}). Using fallback.")
+                    st.session_state.invoice = get_mock_invoice()
+
+with col2:
+    if st.session_state.invoice:
+        st.subheader("2️⃣ Verification Dashboard")
+        st.json(st.session_state.invoice)
+
+        st.markdown("---")
+        st.subheader("3️⃣ Buyer Consent")
+
+        if not st.session_state.approved:
+            if st.button("✅ Approve Invoice"):
+                st.session_state.approved = True
+                st.rerun()
+        else:
+            st.success("Buyer Approved")
+
+        if st.session_state.approved:
+            st.markdown("---")
+            st.subheader("4️⃣ On-Chain Settlement")
+
+            if not st.session_state.minted:
+                if st.button("⛓️ Mint Receipt on Polygon"):
+                    with st.spinner("Minting on-chain..."):
+                        inv = st.session_state.invoice
+                        payload = f"{inv['invoice_number']}{inv['seller_gstin']}{inv['invoice_amount']}"
+                        receipt_hash = hashlib.sha256(payload.encode()).hexdigest()
+                        receipt_bytes = Web3.to_bytes(hexstr="0x" + receipt_hash)
+
+                        try:
+                            tx = contract.functions.mintReceipt(
+                                receipt_bytes,
+                                inv["seller_gstin"],
+                                int(inv["invoice_amount"])
+                            ).build_transaction({
+                                "from": account.address,
+                                "nonce": w3.eth.get_transaction_count(account.address),
+                                "gas": 250000,
+                                "gasPrice": w3.eth.gas_price,
+                                "chainId": 80002
+                            })
+
+                            signed = w3.eth.account.sign_transaction(tx, PRIVATE_KEY)
+                            tx_hash = w3.eth.send_raw_transaction(signed.raw_transaction)
+
+                            st.session_state.tx_hash = w3.to_hex(tx_hash)
+                            st.session_state.minted = True
+                            st.rerun()
+
+                        except Exception as e:
+                            st.error(f"Mint failed: {e}")
+
+            if st.session_state.minted:
+                st.success("Transaction Confirmed")
+                st.link_button(
+                    "View on PolygonScan",
+                    f"https://amoy.polygonscan.com/tx/{st.session_state.tx_hash}"
+                )
+
+st.markdown("---")
+st.caption("Hackathon Prototype • Gemini 1.5 Flash • Polygon Amoy")