import os
import re
import subprocess
import sys
import tkinter as tk
import shutil
from tkinter import messagebox, simpledialog, ttk
import pexpect

def detect_terminal():
    candidates = [
        ("gnome-terminal", ["--"]),     # modern Ubuntu defaults
        ("x-terminal-emulator", ["-e"]),# Debian/Ubuntu wrapper
        ("xterm", ["-e"]),
        ("konsole", ["-e"]),
        ("lxterminal", ["-e"]),
        ("tilix", ["-e"]),
        ("mate-terminal", ["-e"]),
    ]
    for term, flag in candidates:
        if shutil.which(term):
            return term, flag
    return None, None
    
# Define the command to execute
FIDO_COMMAND = "./fido2-manage.sh"

# Checks the terminal emulator from which "gui.py" is executed
# and sets it for the subprocess commands
TERM, TERM_FLAG = detect_terminal()
if TERM is None:
    messagebox.showerror("Error", "No supported terminal emulator found. Please install xterm or gnome-terminal.")


# Command below for Windows
# FIDO_COMMAND = 'fido2-manage-ui.exe'
# Global variable to store the PIN
PIN = None


# Function to get device list from fido2-manage-ui.exe
def get_device_list():
    try:
        # Execute the command with '-list' argument and capture the output
        result = subprocess.run([FIDO_COMMAND, "-list"], capture_output=True, text=True)
        # Split the output into lines and return as a list
        device_list = result.stdout.strip().split("\n")
        return device_list
    except Exception as e:
        # Handle exceptions (e.g., file not found or command error)
        print(f"Error executing device list command: {e}")
        return []


# Function to set the PIN via dialog
def get_pin():
    global PIN
    PIN = simpledialog.askstring(
        "PIN Code", "Enter PIN code:", show="*"
    )


# Function to execute storage command
def execute_storage_command(device_digit):
    global PIN
    if PIN is None:
        messagebox.showwarning("PIN Required", "PIN is required.")
        return
    
    command = [FIDO_COMMAND, "-storage", "-pin", PIN, "-device", device_digit]

    try:
        result = subprocess.run(command, capture_output=True, text=True)
        if result.returncode == 0:
            # Parse the output and insert into the treeview
            for line in reversed(result.stdout.splitlines()):
                if ": " in line:
                    key, value = line.split(": ", 1)
                    tree.insert("", 0, values=(key, value))
        else:
            raise subprocess.CalledProcessError(result.returncode, command)
    except Exception as e:
        messagebox.showerror(
            "Error", f"Command execution failed: {e}\nOutput: {result.stderr}"
        )


# Function to execute info command and append its output to the grid
def execute_info_command(device_digit):
    global PIN
    
    if PIN is None:
        messagebox.showwarning("PIN Required", "PIN is required.")
        return False
    
    tree.delete(*tree.get_children())
    
    # First, try storage command
    storage_command = [FIDO_COMMAND, "-storage", "-pin", PIN, "-device", device_digit]
    try:
        result = subprocess.run(storage_command, capture_output=True, text=True)

        if result.stderr.find("FIDO_ERR_PIN_INVALID") != -1:
            messagebox.showerror("Error", f"Invalid PIN provided")
            return False

        if result.stderr.find("FIDO_ERR_PIN_AUTH_BLOCKED") != -1:
            messagebox.showerror(
                "Error", f"Wrong PIN provided too many times. Reinsert the key"
            )
            return False

        if result.stderr.find("FIDO_ERR_PIN_REQUIRED") != -1:
            messagebox.showwarning(
                "Warning",
                "No PIN set for this key. You must set a PIN before managing passkeys."
            )
            pin_button.config(text="Set PIN", state=tk.ACTIVE, command=set_pin)
            return False

        if result.stderr.find("FIDO_ERR_INVALID_CBOR") != -1:
            messagebox.showerror(
                "Error",
                f"This is an older key (probably FIDO2.0). No passkey management is possible with this key. Only basic information will be shown.",
            )

        # Check if the subprocess was executed successfully
        if result.returncode == 0:
            for line in result.stdout.splitlines():
                if ": " in line:
                    key, value = line.split(": ", 1)
                    tree.insert("", tk.END, values=(key, value))
        else:
            raise subprocess.CalledProcessError(result.returncode, storage_command)
    except Exception as e:
        messagebox.showerror(
            "Error", f"Command execution failed: {e}\nOutput: {result.stderr}"
        )

    # Then, try info command
    info_command = [FIDO_COMMAND, "-info", "-pin", PIN, "-device", device_digit]
    try:
        result = subprocess.run(info_command, capture_output=True, text=True)
        if result.returncode == 0:
            for line in result.stdout.splitlines():
                if ": " in line:
                    key, value = line.split(": ", 1)
                    tree.insert("", tk.END, values=(key, value))
        else:
            raise subprocess.CalledProcessError(result.returncode, info_command)
    except Exception as e:
        messagebox.showerror(
            "Error", f"Command execution failed: {e}\nOutput: {result.stderr}"
        )
    
    return True


# Function to handle selection event
def on_device_selected(event):
    global PIN
    selected_device = device_var.get()
    # Extract the digit inside the first pair of square brackets
    match = re.search(r"\[(\d+)\]", selected_device)
    PIN = None

    if match:
        device_digit = match.group(1)
        # Prompt for PIN
        get_pin()
    if PIN is not None:
            if execute_info_command(device_digit):
                check_passkeys_button_state()
                check_changepin_button_state()
    else:
        messagebox.showinfo("Device Selected", "No digit found in the selected device")


# Function to check if the "passkeys" button should be enabled
def check_passkeys_button_state():
    passkeys_button_state = tk.DISABLED
    for child in tree.get_children():
        values = tree.item(child, "values")
        if values and len(values) == 2 and values[0] == "existing rk(s)":
            try:
                rk_count = int(values[1])
                if rk_count > 0:
                    passkeys_button_state = tk.NORMAL
                    break
            except ValueError:
                pass

    passkeys_button.config(state=passkeys_button_state)


# Function to check if the change PIN button should be enabled
def check_changepin_button_state():
    changepin_button_state = tk.DISABLED
    for child in tree.get_children():
        values = tree.item(child, "values")
        if values and len(values) == 2 and values[0] == "remaining rk(s)":
            try:
                rk_count = int(values[1])
                if rk_count > 0:
                    changepin_button_state = tk.NORMAL
                    break
            except ValueError:
                pass

    change_pin_button.config(state=changepin_button_state)


# Function to handle "passkeys" button click
def on_passkeys_button_click():
    global PIN
    # Get the selected device and PIN
    selected_device = device_var.get()
    match = re.search(r"\[(\d+)\]", selected_device)
    if match:
        device_digit = match.group(1)
        
        # Prompt for PIN if not already set
        if PIN is None:
            get_pin()
        
        # Check again if PIN was entered
        if PIN is None:
            messagebox.showwarning("PIN Required", "PIN is required to manage passkeys.")
            return
        
        # Execute the command to get resident keys
        command = [
            FIDO_COMMAND,
            "-residentKeys",
            "-pin",
            PIN,
            "-device",
            device_digit,
        ]
        try:
            result = subprocess.run(command, capture_output=True, text=True)
            if result.returncode == 0:
                # Parse the domains from the output
                domains = []
                for line in result.stdout.splitlines():
                    match = re.search(r"= (.+)$", line)
                    if match:
                        domains.append(match.group(1))

                # Execute the command for each domain
                cumulated_output = []
                for domain in domains:

                    domain_command = [
                        FIDO_COMMAND,
                        "-residentKeys",
                        "-domain",
                        domain,
                        "-pin",
                        PIN,
                        "-device",
                        device_digit,
                    ]
                    domain_result = subprocess.run(
                        domain_command, capture_output=True, text=True
                    )

                    if domain_result.returncode == 0:
                        cumulated_output.append(
                            f"Domain: {domain}\n{domain_result.stdout}"
                        )
                    else:
                        raise subprocess.CalledProcessError(
                            domain_result.returncode, domain_command
                        )

                # Show the cumulated output in a new window
                cumulated_output_str = "\n\n".join(cumulated_output)
                show_output_in_new_window(cumulated_output_str, device_digit)
            else:
                raise subprocess.CalledProcessError(result.returncode, command)
        except Exception as e:
            messagebox.showerror(
                "Error", f"Command execution failed: {e}\nOutput: {result.stderr}"
            )
    else:
        messagebox.showinfo("Device Selected", "No digit found in the selected device")


def set_pin():
    """Set a new PIN on the device with full interactive control"""
    global PIN
    selected_device = device_var.get()
    match = re.search(r"\[(\d+)\]", selected_device)
    if not match:
        return

    device_digit = match.group(1)

    # Ask for new PIN
    while True:    
        new_pin = simpledialog.askstring(
            "New PIN", "Enter your new PIN code:", show="*"
        )
        if new_pin is None:  # User cancelled
            return
            
        new_pin_confirmed = simpledialog.askstring(
            "Confirm new PIN", "Confirm your new PIN code:", show="*"
        )
        if new_pin_confirmed is None:  # User cancelled
            return
            
        if new_pin == new_pin_confirmed:
            break
        else:
            messagebox.showerror("Error", "New PIN entries do not match!")
            continue

    command = f"{FIDO_COMMAND} -setPIN -device {device_digit}"

    # Enter new PIN in interactive shell
    try:
        child = pexpect.spawn(command, encoding="utf-8", timeout=20)

        child.expect("Enter new PIN")
        child.sendline(new_pin)
        child.expect("Enter the same PIN again")
        child.sendline(new_pin_confirmed)

        PIN = new_pin

        child.expect(pexpect.EOF)
        output = child.before.strip()

        change_pin_button.config(text="Change PIN", state=tk.ACTIVE, command=change_pin)

        if "FIDO_ERR_PIN_POLICY_VIOLATION" in output:
            match = re.search(r"minpinlen:\s*(\d+)", output)
            if match:
                min_pin_len = match.group(1)
            else:
                min_pin_len = "unknown"
            messagebox.showerror(
                "PIN not accepted.",
                f"The provided PIN does not fulfill the requirements of your device.\n"
                f"The PIN has to be at least {min_pin_len} long and must not be an easily guessable sequence, like e.g. 123456"
            )

        elif "error" in output.lower() or "FIDO_ERR" in output:
            messagebox.showerror("PIN Change Failed", output)
        else:
            messagebox.showinfo("Success", "PIN successfully set!")

    except pexpect.exceptions.TIMEOUT:
        messagebox.showerror("Timeout", "The device did not respond in time.")
    except Exception as e:
        messagebox.showerror("Error", str(e))


def change_pin():
    """Change PIN with interactive control and touch detection"""
    global PIN
    
    if PIN is None:
        get_pin()

    selected_device = device_var.get()
    match = re.search(r"\[(\d+)\]", selected_device)
    if not match:
        return

    device_digit = match.group(1)
    
    while True:
        new_pin = simpledialog.askstring(
            "New PIN", "Enter your new PIN code:", show="*"
        )
        if new_pin is None:  # User cancelled
            return
            
        new_pin_confirmed = simpledialog.askstring(
            "Confirm new PIN", "Confirm your new PIN code:", show="*"
        )
        if new_pin_confirmed is None:  # User cancelled
            return
            
        if new_pin == new_pin_confirmed:
            break
        else:
            messagebox.showerror("Error", "New PIN entries do not match!")
            continue

    command = f"{FIDO_COMMAND} -changePIN -device {device_digit}"

    try:
        child = pexpect.spawn(command, encoding="utf-8", timeout=20)

        # --- Detect touch prompt ---
        i = child.expect([
            "Touch", 
            "Tap", 
            "Waiting for user", 
            "Enter current PIN",  # sometimes no touch required
            pexpect.EOF,
            pexpect.TIMEOUT
        ], timeout=5)

        if i in [0, 1, 2]:  
            # Prompt the user in the GUI
            messagebox.showinfo(
                "Touch Required",
                "Please touch your FIDO security key to continue."
            )
            # Now wait until the key is actually touched
            child.expect("Enter current PIN", timeout=30)

        # Now continue with PIN entry
        child.sendline(PIN)

        child.expect("Enter new PIN")
        child.sendline(new_pin)
        child.expect("Enter the same PIN again")
        child.sendline(new_pin_confirmed)

        PIN = new_pin

        output = child.before.strip()
        
        idx = child.expect(["FIDO_ERR_PIN_POLICY_VIOLATION", pexpect.EOF], timeout=1)
        if idx == 0:
            command = f"{FIDO_COMMAND} -info -device {device_digit}"
            info = pexpect.spawn(command, encoding="utf-8")
            info.expect(pexpect.EOF)
            info_text = info.before

            print("info_text:\n", info_text)

            # extract minpinlen
            match = re.search(r"minpinlen:\s*(\d+)", info_text)
            if match:
                min_pin_len = match.group(1)
            else:
                min_pin_len = "?"

            messagebox.showerror(
                "PIN not accepted",
                f"The provided PIN violates the device policy.\n"
                f"The PIN must be at least {min_pin_len} digits long and "
                f"must not be an easily guessable sequence (e.g. 123456)."
            )

            return

        # If no violation detected, EOF happened normally
        child.expect(pexpect.EOF)
        output = child.before.strip()

        if "error" in output.lower() or "FIDO_ERR" in output:
            messagebox.showerror("PIN Change Failed", output)
        else:
            messagebox.showinfo("Success", "PIN successfully changed!")

    except pexpect.exceptions.TIMEOUT:
        messagebox.showerror("Timeout", "The device did not respond in time.")
    except Exception as e:
        messagebox.showerror("Error", str(e))


def refresh_combobox():
    """Refresh device list and reset all states"""
    global PIN
    device_combobox.set("")  # Clear the selected value
    tree.delete(*tree.get_children())
    passkeys_button.config(state=tk.DISABLED)
    change_pin_button.config(state=tk.DISABLED)
    PIN = None  # Reset PIN on refresh
    device_list = get_device_list()
    if not device_list:
        print("No devices found.")
    device_combobox["values"] = device_list  # Update the combobox values


# Function to show the output in a new window
def show_output_in_new_window(output, device_digit):
    # Create a new window
    new_window = tk.Toplevel(root)
    new_window.geometry("800x650")
    new_window.title("Resident Keys / Passkeys")

    # Create a Treeview widget for displaying output
    tree_new_window = ttk.Treeview(
        new_window, columns=("Domain", "Credential ID", "User"), show="headings"
    )
    # Set column headings
    tree_new_window.heading("Domain", text="Domain")
    tree_new_window.heading("Credential ID", text="Credential ID")
    tree_new_window.heading("User", text="User")
    tree_new_window.pack(expand=True, fill=tk.BOTH, padx=10, pady=10)

    # Add scrollbars to the Treeview
    tree_scrollbar_y = ttk.Scrollbar(
        new_window, orient="vertical", command=tree_new_window.yview
    )
    tree_scrollbar_y.pack(side="right", fill="y")
    tree_new_window.configure(yscrollcommand=tree_scrollbar_y.set)
    tree_scrollbar_x = ttk.Scrollbar(
        new_window, orient="horizontal", command=tree_new_window.xview
    )
    tree_scrollbar_x.pack(side="bottom", fill="x")
    tree_new_window.configure(xscrollcommand=tree_scrollbar_x.set)

    # Parse the output and insert into the Treeview
    current_domain = ""
    for line in output.splitlines():
        if line.startswith("Domain: "):
            current_domain = line.split("Domain: ")[1].strip()
        elif "Credential ID: " in line and "User: " in line:
            credential_id = line.split("Credential ID: ")[1].split(",")[0].strip()
            user = line.split("User: ")[1].strip()
            user = re.sub(re.escape(credential_id), "", user).strip()
            tree_new_window.insert(
                "", tk.END, values=(current_domain, credential_id, user)
            )

    # Function to handle delete passkey button click
    def show_selected_value():
        selected_item = tree_new_window.selection()
        if selected_item:
            value = tree_new_window.item(selected_item, "values")[1]  # Get Credential ID
            new_window.destroy()
            command = [
                FIDO_COMMAND,
                "-delete",
                "-device",
                device_digit,
                "-credential",
                value,
            ]
            if sys.platform.startswith("win"):
                subprocess.Popen(["start", "cmd", "/c"] + command, shell=True)
            elif sys.platform.startswith("linux"):
                subprocess.Popen([TERM] + TERM_FLAG + command)

    # Create the "Delete Passkey" button
    show_value_button = tk.Button(
        new_window, text="Delete Passkey", command=show_selected_value
    )
    show_value_button.pack(pady=10)


def show_about_message():
    messagebox.showinfo(
        "About",
        "The FIDO2.1 Security Key Management Tool is a utility designed to manage and interact with FIDO2.1 security keys.\r\n"
        "It provides functionalities to view information, manage passkeys, and perform various operations on connected FIDO2.1 devices.\r\n\r\n"
        "(c)TOKEN2 Sarl\r\nVersoix, Switzerland\r\n\r\n"
        "Version 0.2 - Merged Edition",
    )


# Create the main application window
root = tk.Tk()
root.geometry("700x600")  # Width x Height
root.title("FIDO2.1 Manager - Python version 0.2 - (c) Token2")

# Create a frame for the first three elements
top_frame = ttk.Frame(root)
top_frame.pack(side=tk.TOP, fill=tk.X)

# Create a label for the dropdown
label = tk.Label(top_frame, text="Select Device:")
label.pack(side=tk.LEFT, padx=10, pady=10)

# Create a ComboBox (dropdown) and populate it with device list
device_list = get_device_list()
if not device_list:
    device_list = ["No devices found."]
device_var = tk.StringVar()
device_combobox = ttk.Combobox(
    top_frame, textvariable=device_var, values=device_list, width=60
)
device_combobox.pack(side=tk.LEFT, padx=10, pady=10)
device_combobox.bind("<<ComboboxSelected>>", on_device_selected)

# Create the refresh button
refresh_button = tk.Button(top_frame, text="Refresh", command=refresh_combobox)
refresh_button.pack(side=tk.LEFT, padx=10, pady=10)


# Create a Treeview widget for displaying output with scrollbars
tree_frame = ttk.Frame(root)
tree_frame.pack(expand=True, fill=tk.BOTH, padx=10, pady=10)
tree_scrollbar_y = ttk.Scrollbar(tree_frame, orient="vertical")
tree_scrollbar_x = ttk.Scrollbar(tree_frame, orient="horizontal")
tree = ttk.Treeview(
    tree_frame,
    columns=("Key", "Value"),
    show="headings",
    yscrollcommand=tree_scrollbar_y.set,
    xscrollcommand=tree_scrollbar_x.set,
)
tree_scrollbar_y.config(command=tree.yview)
tree_scrollbar_x.config(command=tree.xview)
tree_scrollbar_y.pack(side="right", fill="y")
tree_scrollbar_x.pack(side="bottom", fill="x")
# Set column headings
tree.heading("Key", text="Key")
tree.heading("Value", text="Value")
tree.pack(expand=True, fill=tk.BOTH)

# Create the "Passkeys" button
passkeys_button = ttk.Button(
    root, text="Passkeys", state=tk.DISABLED, command=on_passkeys_button_click
)
passkeys_button.pack(side=tk.LEFT, padx=5, pady=10)

# Create the "Change PIN" button
change_pin_button = ttk.Button(
    root, text="Change PIN", state=tk.DISABLED, command=change_pin
)
change_pin_button.pack(side=tk.LEFT, padx=5, pady=10)

# Create the "About" button
about_button = ttk.Button(root, text="About", command=show_about_message)
about_button.pack(side=tk.RIGHT, padx=5, pady=10)


# Run the Tkinter main loop
root.mainloop()