# Copyright (c) Meta Platforms, Inc. and affiliates.
# All rights reserved.
#
# This source code is licensed under the BSD-style license found in the
# LICENSE file in the root directory of this source tree.

"""
FastAPI application for the Etl Environment.

This module creates an HTTP server that exposes the EtlEnvironment
over HTTP and WebSocket endpoints, compatible with EnvClient.

Endpoints:
    - POST /reset: Reset the environment
    - POST /step: Execute an action
    - GET /state: Get current environment state
    - GET /schema: Get action/observation schemas
    - WS /ws: WebSocket endpoint for persistent sessions

Usage:
    # Development (with auto-reload):
    uvicorn server.app:app --reload --host 0.0.0.0 --port 8000

    # Production:
    uvicorn server.app:app --host 0.0.0.0 --port 8000 --workers 4

    # Or run directly:
    python -m server.app
"""

try:
    from openenv.core.env_server.http_server import create_app
except Exception as e:  # pragma: no cover
    raise ImportError(
        "openenv is required for the web interface. Install dependencies with '\n    uv sync\n'"
    ) from e

try:
    from ..models import EtlAction, EtlObservation
    from .etl_environment import EtlEnvironment
# In Docker/Spaces, this module is often imported as top-level `server.app`,
# where `..models` is invalid and raises ImportError instead of ModuleNotFoundError.
except ImportError:
    from models import EtlAction, EtlObservation
    from server.etl_environment import EtlEnvironment


# Create the app with web interface and README integration
app = create_app(
    EtlEnvironment,
    EtlAction,
    EtlObservation,
    env_name="etl",
    max_concurrent_envs=1,  # increase this number to allow more concurrent WebSocket sessions
)


def main(host: str = "0.0.0.0", port: int = 8000):
    """
    Entry point for direct execution via uv run or python -m.

    Reads --host and --port from sys.argv when called with no arguments
    (e.g. via the [project.scripts] entry point or a bare ``main()`` call),
    so the function is always callable without arguments.

    This function enables running the server without Docker:
        uv run --project . server
        uv run --project . server --port 8001
        python -m etl.server.app

    Args:
        host: Host address to bind to (default: "0.0.0.0"). Overridable via
              --host CLI argument when called with no explicit arguments.
        port: Port number to listen on (default: 8000). Overridable via
              --port CLI argument when called with no explicit arguments.

    For production deployments, consider using uvicorn directly with
    multiple workers:
        uvicorn etl.server.app:app --workers 4
    """
    import argparse
    import uvicorn

    # Only parse CLI args when called with the defaults (i.e. no explicit
    # caller-supplied values).  This preserves programmatic callability while
    # still honouring --host / --port when launched from the command line.
    if host == "0.0.0.0" and port == 8000:
        parser = argparse.ArgumentParser(description="ETL Pipeline Fixer env server")
        parser.add_argument("--host", type=str, default="0.0.0.0")
        parser.add_argument("--port", type=int, default=8000)
        # parse_known_args so uvicorn / pytest fixtures don't choke on extra flags
        args, _ = parser.parse_known_args()
        host = args.host
        port = args.port

    uvicorn.run(app, host=host, port=port)


if __name__ == "__main__":
    main()