import os
import shutil
import psutil
# Try to import readline or fallback to pyreadline3 (Windows)
try:
    import readline
except ImportError:
    try:
        import pyreadline3 as readline
    except ImportError:
        readline = None  # no history/autocomplete on Windows if missing


# ========== Optional AI Module (Natural Language Commands) ==========
try:
    from transformers import pipeline
    ai_enabled = True
    nlp = pipeline("text2text-generation", model="google/flan-t5-small")
except Exception:
    ai_enabled = False


# ========== Command Handlers ==========
def cmd_ls(args):
    path = args[0] if args else "."
    try:
        for item in os.listdir(path):
            print(item)
    except FileNotFoundError:
        print(f"ls: cannot access '{path}': No such file or directory")


def cmd_cd(args):
    if not args:
        print("cd: missing operand")
        return
    try:
        os.chdir(args[0])
    except FileNotFoundError:
        print(f"cd: {args[0]}: No such file or directory")


def cmd_pwd(args):
    print(os.getcwd())


def cmd_mkdir(args):
    if not args:
        print("mkdir: missing operand")
        return
    try:
        os.mkdir(args[0])
    except FileExistsError:
        print(f"mkdir: cannot create directory '{args[0]}': File exists")


def cmd_rm(args):
    if not args:
        print("rm: missing operand")
        return
    target = args[0]
    if os.path.isdir(target):
        try:
            shutil.rmtree(target)
        except Exception as e:
            print(f"rm: cannot remove '{target}': {e}")
    else:
        try:
            os.remove(target)
        except FileNotFoundError:
            print(f"rm: cannot remove '{target}': No such file or directory")


def cmd_monitor(args):
    cpu = psutil.cpu_percent(interval=1)
    mem = psutil.virtual_memory()
    print(f"CPU Usage: {cpu}%")
    print(f"Memory Usage: {mem.percent}%")


def cmd_help(args):
    print("Available commands:")
    for cmd in commands.keys():
        print(f" - {cmd}")
    if ai_enabled:
        print(" - ai (natural language queries)")


# ========== AI Command ==========
def cmd_ai(args):
    if not ai_enabled:
        print("AI features not available (transformers not installed).")
        return
    if not args:
        print("ai: missing query")
        return
    query = " ".join(args)
    print(f"AI Query: {query}")
    try:
        result = nlp(query, max_length=100)[0]['generated_text']
        print("AI Suggestion:", result)
    except Exception as e:
        print(f"AI error: {e}")


# ========== Command Map ==========
commands = {
    "ls": cmd_ls,
    "cd": cmd_cd,
    "pwd": cmd_pwd,
    "mkdir": cmd_mkdir,
    "rm": cmd_rm,
    "monitor": cmd_monitor,
    "help": cmd_help,
    "ai": cmd_ai,
}


# ========== Autocomplete ==========
def completer(text, state):
    options = [cmd for cmd in commands.keys() if cmd.startswith(text)]
    if state < len(options):
        return options[state]
    return None

if readline:
    readline.parse_and_bind("tab: complete")
    readline.set_completer(completer)


# ========== Main Loop ==========
def main():
    print("Python Terminal Emulator (type 'help' for commands, 'exit' to quit)")
    while True:
        try:
            user_input = input(f"{os.getcwd()} $ ").strip()
            if not user_input:
                continue
            if user_input.lower() in ["exit", "quit"]:
                print("Exiting terminal.")
                break

            parts = user_input.split()
            cmd, args = parts[0], parts[1:]

            if cmd in commands:
                commands[cmd](args)
            else:
                print(f"{cmd}: command not found. Type 'help' for available commands.")
        except KeyboardInterrupt:
            print("\nUse 'exit' to quit.")
        except Exception as e:
            print("Error:", e)


if __name__ == "__app__":
    main()