import tempfile
import pandas as pd
import numpy as np
import gradio as gr

def greet(name="Stranger", intensity=1, exclaim=False):
    greeting = f"Hello, {name}{'!' * int(intensity)}"
    if exclaim:
        greeting = greeting.upper()
    return greeting

def calculator(num1, operation, num2):
    if operation == "add":
        result = num1 + num2
    elif operation == "subtract":
        result = num1 - num2
    elif operation == "multiply":
        result = num1 * num2
    elif operation == "divide":
        if num2 == 0:
            raise gr.Error("Cannot divide by zero!")
        result = num1 / num2
    return result

def sepia(input_img):
    sepia_filter = np.array([
        [0.393, 0.769, 0.189],
        [0.349, 0.686, 0.168],
        [0.272, 0.534, 0.131]
    ])
    sepia_img = input_img @ sepia_filter.T
    sepia_img = np.clip(sepia_img, 0, 255).astype(np.uint8)
    return sepia_img

def download_text(text):
    if not text:
        text = ""
    with tempfile.NamedTemporaryFile(delete=False, suffix=".txt", mode="w", encoding="utf-8") as f:
        f.write(text)
        return f.name

def download_csv(result):
    if result is None:
        result = ""
    df = pd.DataFrame({"Result": [result]})
    with tempfile.NamedTemporaryFile(delete=False, suffix=".csv", mode="w", encoding="utf-8") as f:
        df.to_csv(f, index=False)
        return f.name