import gradio as gr
import string
import secrets
import math

SYMBOLS = "!@#$%^&*()-_=+[]{}|;:,.<>?/"

def analyze_password(length, pool_size):
    entropy = length * math.log2(pool_size)

    if entropy < 40:
        strength = "Weak"
        crack_time = "Seconds to Minutes"
    elif entropy < 60:
        strength = "Medium"
        crack_time = "Hours to Days"
    elif entropy < 80:
        strength = "Strong"
        crack_time = "Years"
    elif entropy < 100:
        strength = "Very Strong"
        crack_time = "Millions of Years"
    else:
        strength = "Extremely Strong"
        crack_time = "Practically Uncrackable"

    return entropy, strength, crack_time


def generate_password(length, letters, numbers, symbols, allow_repeats):
    try:
        length = int(length)
    except:
        return "Error", "Length must be a valid number."

    if length <= 0:
        return "Error", "Length must be greater than 0."

    pool = ""

    if letters:
        pool += string.ascii_letters

    if numbers:
        pool += string.digits

    if symbols:
        pool += SYMBOLS

    if not pool:
        return "Error", "Select at least one character type."

    unique_chars = len(set(pool))

    if not allow_repeats and length > unique_chars:
        selected = []

        if letters:
            selected.append("Letters")

        if numbers:
            selected.append("Numbers")

        if symbols:
            selected.append("Symbols")

        return (
            "Impossible Request",
            f"You selected: {', '.join(selected)}\n"
            f"Repeated characters disabled.\n\n"
            f"Only {unique_chars} unique characters are available,\n"
            f"but you requested {length} characters."
        )

    if allow_repeats:
        password = "".join(
            secrets.choice(pool)
            for _ in range(length)
        )
    else:
        password = "".join(
            secrets.SystemRandom().sample(pool, length)
        )

    entropy, strength, crack_time = analyze_password(
        len(password),
        len(set(pool))
    )

    analysis = (
        f"Strength: {strength}\n"
        f"Entropy: {entropy:.1f} bits\n"
        f"Estimated Crack Time: {crack_time}"
    )

    return password, analysis


with gr.Blocks(title="Password Generator V2") as demo:
    gr.Markdown("# 🔐 Password Generator V2")
    gr.Markdown(
        "Generate secure passwords and estimate their strength."
    )

    length = gr.Number(
        value=16,
        label="Password Length",
        minimum=1,
        precision=0
    )

    with gr.Row():
        letters = gr.Checkbox(
            value=True,
            label="Letters (A-Z, a-z)"
        )

        numbers = gr.Checkbox(
            value=True,
            label="Numbers (0-9)"
        )

        symbols = gr.Checkbox(
            value=False,
            label="Symbols"
        )

    allow_repeats = gr.Checkbox(
        value=True,
        label="Allow Repeated Characters"
    )

    generate_btn = gr.Button("Generate Password")

    password_output = gr.Textbox(
        label="Generated Password",
        lines=2
    )

    analysis_output = gr.Textbox(
        label="Password Analysis",
        lines=4
    )

    generate_btn.click(
        fn=generate_password,
        inputs=[
            length,
            letters,
            numbers,
            symbols,
            allow_repeats
        ],
        outputs=[
            password_output,
            analysis_output
        ]
    )

demo.launch()