app.py

from dotenv import load_dotenv
load_dotenv()

import streamlit as st
import os
from PIL import Image
from google import genai
from google.genai import types

client = genai.Client(api_key=os.getenv("GOOGLE_API_KEY"))

def get_gemini_response(system_prompt, image_parts, user_question):
    response = client.models.generate_content(
        model="gemini-3-flash-preview",
        contents=[
            types.Part.from_bytes(
                data=image_parts[0]["data"],
                mime_type=image_parts[0]["mime_type"]
            ),
            f"{system_prompt}\n\nQuestion: {user_question}"
        ]
    )
    return response.text

def input_image_details(uploaded_file):
    if uploaded_file is not None:
        return [{
            "mime_type": uploaded_file.type,
            "data": uploaded_file.getvalue()
        }]
    raise FileNotFoundError("No File Uploaded")

st.set_page_config(page_title="Multi Language Invoice Extractor")
st.header("Multi Language Invoice Extractor")

user_input = st.text_input("Ask a question about the invoice:", key="input")
uploaded_file = st.file_uploader("Upload invoice image", type=['jpg', 'jpeg', 'png'])

if uploaded_file is not None:
    st.image(Image.open(uploaded_file), caption="Uploaded Invoice", use_column_width=True)

submit = st.button("Analyze Invoice")

input_prompt = """
You are InvoiceIQ, an expert AI document analyst specializing in invoices, receipts, 
purchase orders, and financial documents across all formats, languages, and currencies.

DOCUMENT ANALYSIS PROTOCOL:
Before answering any question, silently extract the following from the invoice:
- Invoice number, issue date, due date
- Vendor: name, address, tax ID, contact info
- Customer: name, address, tax ID
- Line items: description, quantity, unit price, line total
- Subtotal, taxes (type + rate + amount), discounts, total amount
- Currency, payment terms, payment method, bank details
- PO number, notes, stamp/signature presence

REASONING CHAIN (follow silently before every response):
1. Locate the relevant section(s) of the invoice
2. Read the exact value — do not infer or estimate
3. If ambiguous or illegible, say so explicitly with confidence level
4. Cross-validate amounts (line items should sum to subtotal; subtotal + tax = total)
5. Then formulate your answer

RESPONSE FORMAT:
- Answer the user's question directly and concisely first
- If the answer is a number/amount, always include the currency symbol/code
- If asked for full extraction, return a structured JSON block followed by a prose summary
- Flag any discrepancies (e.g., totals that don't add up) as ⚠️ warnings

CONFIDENCE SIGNALS:
- Use [HIGH] when the field is clearly visible and unambiguous
- Use [MEDIUM] when inferred from context or partially legible  
- Use [LOW] when guessed or heavily obscured — always recommend human verification

EDGE CASE HANDLING:
- Multiple currencies: preserve each currency exactly as shown
- Handwritten or damaged documents: describe what is legible, flag what is not
- Missing fields: respond with "Not present on invoice" — never fabricate values

LANGUAGE: Respond in the same language the user asks the question in.
"""

if submit:
    if uploaded_file is None:
        st.error("Please upload an invoice image first.")
    elif not user_input.strip():
        st.error("Please enter a question.")
    else:
        with st.spinner("Analyzing invoice..."):
            image_data = input_image_details(uploaded_file)
            response = get_gemini_response(input_prompt, image_data, user_input)
            st.subheader("Response")
            st.write(response)