app.py

import gradio as gr

# Conversion logic
def convert_units(category, from_unit, to_unit, value):
    try:
        value = float(value)
    except:
        return "Invalid input value"

    conversions = {
        "Length": {
            "units": ["Meters", "Kilometers", "Feet", "Miles"],
            "factors": {
                "Meters": 1,
                "Kilometers": 1000,
                "Feet": 0.3048,
                "Miles": 1609.34
            }
        },
        "Weight": {
            "units": ["Grams", "Kilograms", "Pounds", "Ounces"],
            "factors": {
                "Grams": 1,
                "Kilograms": 1000,
                "Pounds": 453.592,
                "Ounces": 28.3495
            }
        },
        "Temperature": {
            "units": ["Celsius", "Fahrenheit", "Kelvin"]
        }
    }

    if category == "Temperature":
        if from_unit == to_unit:
            return value
        if from_unit == "Celsius":
            if to_unit == "Fahrenheit":
                return (value * 9/5) + 32
            elif to_unit == "Kelvin":
                return value + 273.15
        elif from_unit == "Fahrenheit":
            if to_unit == "Celsius":
                return (value - 32) * 5/9
            elif to_unit == "Kelvin":
                return (value - 32) * 5/9 + 273.15
        elif from_unit == "Kelvin":
            if to_unit == "Celsius":
                return value - 273.15
            elif to_unit == "Fahrenheit":
                return (value - 273.15) * 9/5 + 32
    else:
        base_value = value * conversions[category]["factors"][from_unit]
        return base_value / conversions[category]["factors"][to_unit]

# UI layout
categories = ["Length", "Weight", "Temperature"]
units = {
    "Length": ["Meters", "Kilometers", "Feet", "Miles"],
    "Weight": ["Grams", "Kilograms", "Pounds", "Ounces"],
    "Temperature": ["Celsius", "Fahrenheit", "Kelvin"]
}

def unit_converter_app(category, from_unit, to_unit, value):
    result = convert_units(category, from_unit, to_unit, value)
    return f"{value} {from_unit} = {result:.4f} {to_unit}"

with gr.Blocks() as demo:
    gr.Markdown("# 🔁 Unit Converter App")
    
    category_input = gr.Dropdown(choices=categories, label="Category", value="Length")
    from_unit_input = gr.Dropdown(choices=units["Length"], label="From Unit")
    to_unit_input = gr.Dropdown(choices=units["Length"], label="To Unit")
    value_input = gr.Textbox(label="Enter value")

    output = gr.Textbox(label="Result")

    def update_units(category):
        return gr.update(choices=units[category], value=units[category][0]), gr.update(choices=units[category], value=units[category][1])
    
    category_input.change(fn=update_units, inputs=category_input, outputs=[from_unit_input, to_unit_input])

    convert_button = gr.Button("Convert")
    convert_button.click(fn=unit_converter_app, inputs=[category_input, from_unit_input, to_unit_input, value_input], outputs=output)

demo.launch()