#!/usr/bin/env python3
import argparse
import os
import subprocess
import sys
from pathlib import Path

def get_real_user_info():
    """
    Detects the real user when running under sudo.
    Falls back to normal environment variables if not running under sudo.
    """
    sudo_user = os.environ.get("SUDO_USER")
    sudo_uid = os.environ.get("SUDO_UID")
    sudo_gid = os.environ.get("SUDO_GID")

    if sudo_user and sudo_uid and sudo_gid:
        return sudo_user, int(sudo_uid), int(sudo_gid), Path(f"/home/{sudo_user}")
    else:
        return (
            os.environ.get("USER", "root"),
            os.getuid(),
            os.getgid(),
            Path.home()
        )

def run_cmd(cmd, check=True):
    """Helper to run shell commands."""
    try:
        return subprocess.run(cmd, check=check, text=True)
    except subprocess.CalledProcessError as e:
        print(f"Error executing command: {' '.join(cmd)}", file=sys.stderr)
        sys.exit(e.returncode)

def handle_list(args):
    # Pass the user.lxcd=true filter directly to LXD's native listing engine
    run_cmd(["lxc", "list", "user.lxcd=true"])

def handle_clone(args):
    print(f"Cloning container '{args.source}' to '{args.name}'...")

    # 1. Native LXD copy (duplicates the filesystem, mounts, and tags)
    run_cmd(["lxc", "copy", args.source, args.name])

    # 2. Start the new cloned container
    print(f"Starting cloned container '{args.name}'...")
    run_cmd(["lxc", "start", args.name])

    # 3. Wait for network/cloud-init stabilization
    run_cmd(["lxc", "exec", args.name, "--", "cloud-init", "status", "--wait"], check=False)

    print(f"Container '{args.name}' cloned successfully from '{args.source}'!")

def handle_create(args):
    host_username, uid, gid, host_home = get_real_user_info()
    
    # Paths for targeted workspace sharing
    host_coder_dir = host_home / "Coder"
    container_coder_path = f"/home/{host_username}/Coder"
    
    # Ensure the 'Coder' directory exists on the host machine
    if not host_coder_dir.exists():
        print(f"Creating missing directory on host: {host_coder_dir}")
        host_coder_dir.mkdir(parents=True, exist_ok=True)
        os.chown(host_coder_dir, uid, gid)

    print(f"Creating LXD container '{args.name}' from image '{args.image}'...")
    
    # Cloud-init configuration that drops stock 'ubuntu' user and seeds defaults
    cloud_config = f"""#cloud-config
users:
  - name: {host_username}
    gecos: lxcd user
    primary_group: {host_username}
    groups: [adm, sudo, plugdev]
    shell: /bin/bash
    sudo: ALL=(ALL) NOPASSWD:ALL
    lock_passwd: true
    homedir: /home/{host_username}

groups:
  - {host_username}

runcmd:
  # Copy missing skeleton files (without overwriting existing mounts) and fix ownership
  - cp -rpn /etc/skel/. /home/{host_username}/
  - chown -R {host_username}:{host_username} /home/{host_username}/
"""

    # Initialize container
    run_cmd(["lxc", "init", args.image, args.name])

    # Tag the container so lxcd knows it owns it
    print("Tagging container as managed by lxcd...")
    run_cmd(["lxc", "config", "set", args.name, "user.lxcd", "true"])

    # Inject Cloud-init settings
    print(f"Injecting cloud-init config for user '{host_username}'...")
    run_cmd(["lxc", "config", "set", args.name, "cloud-init.user-data", cloud_config])

    # Mount host's Coder directory using shift=true
    print(f"Mounting host {host_coder_dir} -> {container_coder_path} (shift=true)...")
    run_cmd([
        "lxc", "config", "device", "add", args.name, "host-coder", "disk",
        f"source={host_coder_dir}", 
        f"path={container_coder_path}", 
        "shift=true"
    ])

    # Handle --git option
    if args.git:
        gitconfig_path = host_home / ".gitconfig"
        if gitconfig_path.exists():
            container_git_path = f"/home/{host_username}/.gitconfig"
            print(f"Mapping host git configurations to {container_git_path} (shift=true)...")
            run_cmd([
                "lxc", "config", "device", "add", args.name, "gitconfig", "disk",
                f"source={gitconfig_path}", 
                f"path={container_git_path}", 
                "shift=true"
            ])
        else:
            print(f"Warning: --git requested, but {gitconfig_path} was not found on host.", file=sys.stderr)

    # Handle --nested option
    if args.nested:
        print("Enabling nesting capabilities...")
        run_cmd(["lxc", "config", "set", args.name, "security.nesting", "true"])
        run_cmd(["lxc", "config", "set", args.name, "security.syscalls.intercept.mknod", "true"])

    # Start container and await cloud-init provisioning
    print("Starting container and executing cloud-init user provisioning...")
    run_cmd(["lxc", "start", args.name])
    run_cmd(["lxc", "exec", args.name, "--", "cloud-init", "status", "--wait"], check=False)

    print(f"Container '{args.name}' is ready! Workspace mounted at {container_coder_path}")

def handle_enter(args):
    _, uid, gid, host_home = get_real_user_info()
    host_cwd = os.getcwd()
    
    # Dynamically find the user matching your UID inside the container
    try:
        result = subprocess.run(
            ["lxc", "exec", args.name, "--", "id", "-nu", str(uid)],
            capture_output=True, text=True, check=True
        )
        container_username = result.stdout.strip()
    except subprocess.CalledProcessError:
        container_username = "root"

    container_home = f"/home/{container_username}"

    # Smart CWD Mapping: Ensure the host directory actually exists in the container
    host_coder_dir = str(host_home / "Coder")
    container_coder_dir = f"{container_home}/Coder"
    
    # If the user is inside the mapped Coder directory on the host, translate the path
    if host_cwd.startswith(host_coder_dir):
        target_cwd = host_cwd.replace(host_coder_dir, container_coder_dir, 1)
    else:
        # Fallback to the container's home directory if executed from an unmapped host path
        target_cwd = container_home

    env_prefix = (
        f"HOME={container_home} "
        f"TERM={os.environ.get('TERM', 'xterm-256color')} "
        f"LANG={os.environ.get('LANG', 'C.UTF-8')} "
    )
    
    display = os.environ.get("DISPLAY")
    if display:
        env_prefix += f"DISPLAY={display} "

    # Execute using native LXD flags for user, group, and working directory
    exec_cmd = [
        "lxc", "exec", args.name, 
        "--cwd", target_cwd,
        "--user", str(uid),
        "--group", str(gid),
        "--", 
        "sh", "-c", f"env {env_prefix} /bin/bash --login"
    ]
    
    os.execvp("lxc", exec_cmd)

def handle_delete(args):
    print(f"Stopping container '{args.name}'...")
    run_cmd(["lxc", "stop", args.name], check=False)
    print(f"Deleting container '{args.name}'...")
    run_cmd(["lxc", "delete", args.name])
    print(f"Container '{args.name}' deleted successfully.")

def handle_rename(args):
    print(f"Preparing to rename '{args.old_name}' to '{args.new_name}'...")

    # 1. LXD requires containers to be stopped before renaming
    print(f"Stopping '{args.old_name}'...")
    # Using stdout/stderr redirection internally to hide the error if it's already stopped
    subprocess.run(
        ["lxc", "stop", args.old_name],
        stdout=subprocess.DEVNULL,
        stderr=subprocess.DEVNULL
    )

    # 2. Execute the rename
    run_cmd(["lxc", "rename", args.old_name, args.new_name])

    # 3. Restart the container under its new name
    print(f"Starting renamed container '{args.new_name}'...")
    run_cmd(["lxc", "start", args.new_name])

    # 4. Wait for it to stabilize
    run_cmd(["lxc", "exec", args.new_name, "--", "cloud-init", "status", "--wait"], check=False)

    print(f"Container successfully renamed to '{args.new_name}'!")

def main():
    parser = argparse.ArgumentParser(description="lxcd: A Distrobox-like wrapper for LXD (Sudo Optimized)")
    subparsers = parser.add_subparsers(dest="command", required=True)

    # Create command
    parser_create = subparsers.add_parser("create", help="Create a new LXD container")
    parser_create.add_argument("name", help="Name of the container")
    parser_create.add_argument("-i", "--image", default="ubuntu:", help="LXD image to use (defaults to 'ubuntu:')")
    parser_create.add_argument("--nested", action="store_true", help="Enable nesting")
    parser_create.add_argument("--git", action="store_true", help="Map host ~/.gitconfig into the container")

    # Clone command
    parser_clone = subparsers.add_parser("clone", help="Clone an existing LXD container")
    parser_clone.add_argument("source", help="Name of the source container")
    parser_clone.add_argument("name", help="Name of the new cloned container")

    # Rename command
    parser_rename = subparsers.add_parser("rename", aliases=["mv"], help="Rename an existing LXD container")
    parser_rename.add_argument("old_name", help="Current name of the container")
    parser_rename.add_argument("new_name", help="New name for the container")

    # Enter command
    parser_enter = subparsers.add_parser("enter", help="Enter an existing LXD container")
    parser_enter.add_argument("name", help="Name of the container to enter")

    # List command
    parser_list = subparsers.add_parser("list", aliases=["ls"], help="List all managed LXD containers")

    # Delete command
    parser_delete = subparsers.add_parser("delete", help="Delete an LXD container")
    parser_delete.add_argument("name", help="Name of the container to delete")

    args = parser.parse_args()

    if args.command == "create":
        handle_create(args)
    elif args.command == "clone":
        handle_clone(args)
    elif args.command in ["rename", "mv"]:
        handle_rename(args)
    elif args.command == "enter":
        handle_enter(args)
    elif args.command in ["list", "ls"]:
        handle_list(args)
    elif args.command == "delete":
        handle_delete(args)

if __name__ == "__main__":
    main()