"""flow dev <subcommand> — container management."""

import os
import shutil
import subprocess
import sys

from flow.core.config import FlowContext

DEFAULT_REGISTRY = "registry.tomastm.com"
DEFAULT_TAG = "latest"
CONTAINER_HOME = "/home/dev"


def register(subparsers):
    p = subparsers.add_parser("dev", help="Manage development containers")
    sub = p.add_subparsers(dest="dev_command")

    # create
    create = sub.add_parser("create", help="Create and start a development container")
    create.add_argument("name", help="Container name")
    create.add_argument("-i", "--image", required=True, help="Container image")
    create.add_argument("-p", "--project", help="Path to project directory")
    create.set_defaults(handler=run_create)

    # exec
    exec_cmd = sub.add_parser("exec", help="Execute command in a container")
    exec_cmd.add_argument("name", help="Container name")
    exec_cmd.add_argument("cmd", nargs="*", help="Command to run (default: interactive shell)")
    exec_cmd.set_defaults(handler=run_exec)

    # connect
    connect = sub.add_parser("connect", help="Attach to container tmux session")
    connect.add_argument("name", help="Container name")
    connect.set_defaults(handler=run_connect)

    # list
    ls = sub.add_parser("list", help="List development containers")
    ls.set_defaults(handler=run_list)

    # stop
    stop = sub.add_parser("stop", help="Stop a development container")
    stop.add_argument("name", help="Container name")
    stop.add_argument("--kill", action="store_true", help="Kill instead of graceful stop")
    stop.set_defaults(handler=run_stop)

    # remove
    remove = sub.add_parser("remove", aliases=["rm"], help="Remove a development container")
    remove.add_argument("name", help="Container name")
    remove.add_argument("-f", "--force", action="store_true", help="Force removal")
    remove.set_defaults(handler=run_remove)

    # respawn
    respawn = sub.add_parser("respawn", help="Respawn all tmux panes for a session")
    respawn.add_argument("name", help="Session/container name")
    respawn.set_defaults(handler=run_respawn)

    p.set_defaults(handler=lambda ctx, args: p.print_help())


def _runtime():
    for rt in ("docker", "podman"):
        if shutil.which(rt):
            return rt
    raise RuntimeError("No container runtime found (docker or podman)")


def _cname(name: str) -> str:
    """Normalize to dev- prefix."""
    return name if name.startswith("dev-") else f"dev-{name}"


def _parse_image_ref(
    image: str,
    *,
    default_registry: str = DEFAULT_REGISTRY,
    default_tag: str = DEFAULT_TAG,
):
    """Parse image shorthand into (full_ref, repo, tag, label)."""
    registry = default_registry
    tag = default_tag

    if image.startswith("docker/"):
        registry = "docker.io"
        image = f"library/{image.split('/', 1)[1]}"
    elif image.startswith("tm0/"):
        registry = default_registry
        image = image.split("/", 1)[1]
    elif "/" in image:
        prefix, remainder = image.split("/", 1)
        if "." in prefix or ":" in prefix or prefix == "localhost":
            registry = prefix
            image = remainder

    if ":" in image.split("/")[-1]:
        tag = image.rsplit(":", 1)[1]
        image = image.rsplit(":", 1)[0]

    repo = image
    full_ref = f"{registry}/{repo}:{tag}"
    label_prefix = registry.rsplit(".", 1)[0].rsplit(".", 1)[-1] if "." in registry else registry
    label = f"{label_prefix}/{repo.split('/')[-1]}"

    return full_ref, repo, tag, label


def _container_exists(rt: str, cname: str) -> bool:
    result = subprocess.run(
        [rt, "container", "ls", "-a", "--format", "{{.Names}}"],
        capture_output=True, text=True,
    )
    return cname in result.stdout.strip().split("\n")


def _container_running(rt: str, cname: str) -> bool:
    result = subprocess.run(
        [rt, "container", "ls", "--format", "{{.Names}}"],
        capture_output=True, text=True,
    )
    return cname in result.stdout.strip().split("\n")


def run_create(ctx: FlowContext, args):
    rt = _runtime()
    cname = _cname(args.name)

    if _container_exists(rt, cname):
        ctx.console.error(f"Container already exists: {cname}")
        sys.exit(1)

    project_path = os.path.realpath(args.project) if args.project else None
    if project_path and not os.path.isdir(project_path):
        ctx.console.error(f"Invalid project path: {project_path}")
        sys.exit(1)

    full_ref, _, _, _ = _parse_image_ref(
        args.image,
        default_registry=ctx.config.container_registry,
        default_tag=ctx.config.container_tag,
    )

    cmd = [
        rt, "run", "-d",
        "--name", cname,
        "--label", "dev=true",
        "--label", f"dev.name={args.name}",
        "--label", f"dev.image_ref={full_ref}",
        "--network", "host",
        "--init",
    ]

    if project_path:
        cmd.extend(["-v", f"{project_path}:/workspace"])
        cmd.extend(["--label", f"dev.project_path={project_path}"])

    docker_sock = "/var/run/docker.sock"
    if os.path.exists(docker_sock):
        cmd.extend(["-v", f"{docker_sock}:{docker_sock}"])

    home = os.path.expanduser("~")
    if os.path.isdir(f"{home}/.ssh"):
        cmd.extend(["-v", f"{home}/.ssh:{CONTAINER_HOME}/.ssh:ro"])
    if os.path.isfile(f"{home}/.npmrc"):
        cmd.extend(["-v", f"{home}/.npmrc:{CONTAINER_HOME}/.npmrc:ro"])
    if os.path.isdir(f"{home}/.npm"):
        cmd.extend(["-v", f"{home}/.npm:{CONTAINER_HOME}/.npm"])

    # Add docker group if available
    try:
        import grp
        docker_gid = str(grp.getgrnam("docker").gr_gid)
        cmd.extend(["--group-add", docker_gid])
    except (KeyError, ImportError):
        pass

    cmd.extend([full_ref, "sleep", "infinity"])
    subprocess.run(cmd, check=True)
    ctx.console.success(f"Created and started container: {cname}")


def run_exec(ctx: FlowContext, args):
    rt = _runtime()
    cname = _cname(args.name)

    if not _container_running(rt, cname):
        ctx.console.error(f"Container {cname} not running")
        sys.exit(1)

    if args.cmd:
        exec_cmd = [rt, "exec"]
        if sys.stdin.isatty():
            exec_cmd.extend(["-it"])
        exec_cmd.append(cname)
        exec_cmd.extend(args.cmd)
        result = subprocess.run(exec_cmd)
        sys.exit(result.returncode)

    # No command — try shells in order
    last_code = 0
    for shell in ("zsh -l", "bash -l", "sh"):
        parts = shell.split()
        exec_cmd = [rt, "exec", "--detach-keys", "ctrl-q,ctrl-p", "-it", cname] + parts
        result = subprocess.run(exec_cmd)
        if result.returncode == 0:
            return
        last_code = result.returncode

    ctx.console.error(f"Unable to start an interactive shell in {cname}")
    sys.exit(last_code or 1)


def run_connect(ctx: FlowContext, args):
    rt = _runtime()
    cname = _cname(args.name)

    if not _container_exists(rt, cname):
        ctx.console.error(f"Container does not exist: {cname}")
        sys.exit(1)

    if not _container_running(rt, cname):
        subprocess.run([rt, "start", cname], capture_output=True)

    if not shutil.which("tmux"):
        ctx.console.warn("tmux not found; falling back to direct exec")
        args.cmd = []
        run_exec(ctx, args)
        return

    # Get image label for env
    result = subprocess.run(
        [rt, "container", "inspect", cname, "--format", "{{ .Config.Image }}"],
        capture_output=True, text=True,
    )
    image_ref = result.stdout.strip()
    _, _, _, image_label = _parse_image_ref(image_ref)

    # Create tmux session if needed
    check = subprocess.run(["tmux", "has-session", "-t", cname], capture_output=True)
    if check.returncode != 0:
        ns = os.environ.get("DF_NAMESPACE", "")
        plat = os.environ.get("DF_PLATFORM", "")
        subprocess.run([
            "tmux", "new-session", "-ds", cname,
            "-e", f"DF_IMAGE={image_label}",
            "-e", f"DF_NAMESPACE={ns}",
            "-e", f"DF_PLATFORM={plat}",
            f"flow dev exec {args.name}",
        ])
        subprocess.run([
            "tmux", "set-option", "-t", cname,
            "default-command", f"flow dev exec {args.name}",
        ])

    if os.environ.get("TMUX"):
        os.execvp("tmux", ["tmux", "switch-client", "-t", cname])
    else:
        os.execvp("tmux", ["tmux", "attach", "-t", cname])


def run_list(ctx: FlowContext, args):
    rt = _runtime()
    result = subprocess.run(
        [rt, "ps", "-a", "--filter", "label=dev=true",
         "--format", '{{.Label "dev.name"}}|{{.Image}}|{{.Label "dev.project_path"}}|{{.Status}}'],
        capture_output=True, text=True,
    )

    headers = ["NAME", "IMAGE", "PROJECT", "STATUS"]
    rows = []
    for line in result.stdout.strip().split("\n"):
        if not line:
            continue
        parts = line.split("|")
        if len(parts) >= 4:
            name, image, project, status = parts[0], parts[1], parts[2], parts[3]
            # Shorten paths
            home = os.path.expanduser("~")
            if project.startswith(home):
                project = "~" + project[len(home):]
            rows.append([name, image, project, status])

    if not rows:
        ctx.console.info("No development containers found.")
        return

    ctx.console.table(headers, rows)


def run_stop(ctx: FlowContext, args):
    rt = _runtime()
    cname = _cname(args.name)

    if not _container_exists(rt, cname):
        ctx.console.error(f"Container {cname} does not exist")
        sys.exit(1)

    if args.kill:
        ctx.console.info(f"Killing container {cname}...")
        subprocess.run([rt, "kill", cname], check=True)
    else:
        ctx.console.info(f"Stopping container {cname}...")
        subprocess.run([rt, "stop", cname], check=True)

    _tmux_fallback(cname)


def run_remove(ctx: FlowContext, args):
    rt = _runtime()
    cname = _cname(args.name)

    if not _container_exists(rt, cname):
        ctx.console.error(f"Container {cname} does not exist")
        sys.exit(1)

    if args.force:
        ctx.console.info(f"Removing container {cname} (force)...")
        subprocess.run([rt, "rm", "-f", cname], check=True)
    else:
        ctx.console.info(f"Removing container {cname}...")
        subprocess.run([rt, "rm", cname], check=True)

    _tmux_fallback(cname)


def run_respawn(ctx: FlowContext, args):
    cname = _cname(args.name)
    result = subprocess.run(
        ["tmux", "list-panes", "-t", cname, "-s",
         "-F", "#{session_name}:#{window_index}.#{pane_index}"],
        capture_output=True, text=True,
    )
    for pane in result.stdout.strip().split("\n"):
        if pane:
            ctx.console.info(f"Respawning {pane}...")
            subprocess.run(["tmux", "respawn-pane", "-t", pane])


def _tmux_fallback(cname: str):
    """If inside tmux in the target session, switch to default."""
    if not os.environ.get("TMUX"):
        return
    result = subprocess.run(
        ["tmux", "display-message", "-p", "#S"],
        capture_output=True, text=True,
    )
    current = result.stdout.strip()
    if current == cname:
        subprocess.run(["tmux", "new-session", "-ds", "default"], capture_output=True)
        subprocess.run(["tmux", "switch-client", "-t", "default"])