app.py

# Dynamic installation safety net
def install_package(package):
    try:
        __import__(package.replace('2', '')) # Check for 'fpdf' namespace
    except ImportError:
        subprocess.check_call([sys.executable, "-m", "pip", "install", package])

install_package("fpdf2")

# Now safe to import
from fpdf import FPDF
import gradio as gr
import pandas as pd
import datetime

# --- 2026 DYNAMIC MARKET DATA ---
MARKET_DATA = {
    "panel_pkr_w": 32,
    "sun_hrs": 5.2,
    "bank_rate": 0.14,  # Simulated Alfalah Rate
    "installation": 0.15
}

def generate_pdf(data):
    pdf = FPDF()
    pdf.add_page()
    pdf.set_font("Helvetica", 'B', 16)
    pdf.cell(0, 10, "Solar Feasibility Report - Pakistan 2026", center=True, new_x="LMARGIN", new_y="NEXT")
    
    pdf.set_font("Helvetica", size=12)
    pdf.ln(10)
    for key, value in data.items():
        pdf.cell(0, 10, f"{key}: {value}", new_x="LMARGIN", new_y="NEXT")
    
    report_path = "Solar_Insights_Report.pdf"
    pdf.output(report_path)
    return report_path

def solar_calculator(ac_count, fan_count, light_count, sys_type):
    # Engineering Math
    load = (ac_count * 1500) + (fan_count * 80) + (light_count * 12)
    daily_units = (load * 8) / 1000
    sys_kw = round((daily_units / MARKET_DATA["sun_hrs"]) * 1.2, 2)
    
    # Financials
    cost = int((sys_kw * 1000 * MARKET_DATA["panel_pkr_w"] + 250000) * (1 + MARKET_DATA["installation"]))
    
    # Bank EMI Calculation (P * r * (1+r)^n / ((1+r)^n - 1))
    p = cost * 0.7  # 30% Downpayment
    r = MARKET_DATA["bank_rate"] / 12
    n = 60
    emi = int(p * (r * (1+r)**n) / ((1+r)**n - 1))

    results = {
        "Total Load (W)": load,
        "System Size (kW)": sys_kw,
        "Total Cost (PKR)": f"{cost:,}",
        "Monthly EMI (PKR)": f"{emi:,}",
        "Date Generated": datetime.datetime.now().strftime("%Y-%m-%d")
    }
    
    pdf_file = generate_pdf(results)
    
    summary = f"""
    ## 📊 Estimation Results
    - **Recommended System:** {sys_kw} kW {sys_type}
    - **Estimated Investment:** PKR {cost:,}
    - **Financing:** PKR {emi:,}/month via Bank Alfalah
    """
    return summary, pdf_file

# --- UI DESIGN ---
with gr.Blocks(title="Solar PK Pro") as demo:
    gr.Markdown("# ☀️ SolarExpert Pakistan 2.0")
    with gr.Row():
        with gr.Column():
            ac = gr.Number(label="Inverter ACs (1.5 Ton)", value=1)
            fans = gr.Number(label="Ceiling Fans", value=4)
            lights = gr.Number(label="LED Lights", value=10)
            stype = gr.Dropdown(["On-Grid", "Hybrid"], label="System Architecture", value="Hybrid")
            calc_btn = gr.Button("Calculate & Generate Report", variant="primary")
        
        with gr.Column():
            out_md = gr.Markdown()
            out_file = gr.File(label="Download PDF Insights")

    calc_btn.click(solar_calculator, inputs=[ac, fans, lights, stype], outputs=[out_md, out_file])

demo.launch()