import gradio as gr
from fastapi import FastAPI, HTTPException
from pydantic import BaseModel

app = FastAPI()

def add(a, b):
    return a + b

def subtract(a, b):
    return a - b

def multiply(a, b):
    return a * b

def divide(a, b):
    if b == 0:
        return "Error: Division by zero"
    return a / b

def calculator(input_text):
    try:
        # Remove all spaces and then add spaces around operators
        input_text = input_text.replace(" ", "")
        for op in ['+', '-', '*', '/']:
            input_text = input_text.replace(op, f" {op} ")
        parts = input_text.split()
        if len(parts) != 3:
            return "Error: Invalid input"
        a = float(parts[0])
        op = parts[1]
        b = float(parts[2])
        if op == '+':
            return str(add(a, b))
        elif op == '-':
            return str(subtract(a, b))
        elif op == '*':
            return str(multiply(a, b))
        elif op == '/':
            return str(divide(a, b))
        else:
            return "Error: Invalid operator"
    except ValueError:
        return "Error: Invalid number"
    except Exception as e:
        return f"Error: {str(e)}"

def append_to_input(current, value):
    if current is None:
        current = ""
    current = str(current)  # Ensure current is a string
    value = str(value)  # Ensure value is a string
    if value in ['+', '-', '*', '/']:
        return f"{current} {value} "
    return current + value

def clear_input():
    return ""

def backspace(current):
    if current is None or current == "":
        return ""
    return current[:-1]

class CalculationInput(BaseModel):
    a: float
    b: float

@app.post("/add")
async def api_add(input: CalculationInput):
    return {"result": add(input.a, input.b)}

@app.post("/subtract")
async def api_subtract(input: CalculationInput):
    return {"result": subtract(input.a, input.b)}

@app.post("/multiply")
async def api_multiply(input: CalculationInput):
    return {"result": multiply(input.a, input.b)}

@app.post("/divide")
async def api_divide(input: CalculationInput):
    if input.b == 0:
        raise HTTPException(status_code=400, detail="Division by zero")
    return {"result": divide(input.a, input.b)}

@app.post("/calculate")
async def api_calculate(input: CalculationInput, operation: str):
    if operation == "+":
        return {"result": add(input.a, input.b)}
    elif operation == "-":
        return {"result": subtract(input.a, input.b)}
    elif operation == "*":
        return {"result": multiply(input.a, input.b)}
    elif operation == "/":
        if input.b == 0:
            raise HTTPException(status_code=400, detail="Division by zero")
        return {"result": divide(input.a, input.b)}
    else:
        raise HTTPException(status_code=400, detail="Invalid operation")

@app.get("/test")
async def test_route():
    return {"message": "FastAPI is working!"}

with gr.Blocks() as demo:
    input_text = gr.Textbox(label="Input", value="")
    output = gr.Textbox(label="Result")
    buttons = [
        ["7", "8", "9", "/"],
        ["4", "5", "6", "*"],
        ["1", "2", "3", "-"],
        ["0", ".", "=", "+"]
    ]
    for row in buttons:
        with gr.Row():
            for button in row:
                if button == "=":
                    gr.Button(button).click(calculator, inputs=input_text, outputs=output)
                else:
                    gr.Button(button).click(
                        lambda x, btn=button: append_to_input(x, btn),
                        inputs=[input_text],
                        outputs=input_text
                    )
    with gr.Row():
        clear_btn = gr.Button("Clear")
        backspace_btn = gr.Button("⌫")
    clear_btn.click(clear_input, inputs=[], outputs=input_text)
    backspace_btn.click(backspace, inputs=[input_text], outputs=input_text)

app = gr.mount_gradio_app(app, demo, path="/")

if __name__ == "__main__":
    import uvicorn
    uvicorn.run(app, host="0.0.0.0", port=7860)