"""FastAPI application for the Python code review environment."""

from __future__ import annotations

import os

from fastapi import APIRouter, HTTPException
from fastapi.responses import RedirectResponse

from compat import create_app

from models import (
    HealthResponse,
    PythonCodeReviewAction,
    PythonCodeReviewObservation,
    PythonCodeReviewState,
    TaskDescriptor,
    TaskGrade,
)
from server.env import PythonCodeReviewEnvironment


try:
    MAX_CONCURRENT_ENVS = max(int(os.getenv("MAX_CONCURRENT_ENVS", "16")), 1)
except Exception:
    MAX_CONCURRENT_ENVS = 16

python_env = PythonCodeReviewEnvironment(verbose=False)
app = create_app(
    PythonCodeReviewEnvironment,
    PythonCodeReviewAction,
    PythonCodeReviewObservation,
    max_concurrent_envs=MAX_CONCURRENT_ENVS,
)
router = APIRouter(tags=["python-code-review"])


@router.get("/", include_in_schema=False)
def root() -> RedirectResponse:
    """Redirect root to API documentation."""
    return RedirectResponse(url="/docs")


@router.get("/health", response_model=HealthResponse)
def health() -> HealthResponse:
    """Health check endpoint for deployment monitoring."""
    return python_env.health()


@router.get("/tasks", response_model=list)
def list_tasks() -> list:
    """List all available deterministic tasks."""
    return python_env.list_task_summaries()


@router.get("/tasks/{task_id}", response_model=object)
def get_task(task_id: str) -> object:
    """Get a specific task by ID."""
    try:
        return python_env.get_task(task_id)
    except ValueError as exc:
        raise HTTPException(status_code=404, detail=str(exc)) from exc


@router.post("/tasks/{task_id}/grade", response_model=TaskGrade)
def grade_task(task_id: str, payload: PythonCodeReviewAction) -> TaskGrade:
    """Grade code submission for a task without running an episode."""
    if payload.action_type != "edit_code" or not payload.code:
        raise HTTPException(
            status_code=400, 
            detail="Requires action_type='edit_code' with code parameter."
        )
    try:
        return python_env.grade_task_submission(task_id=task_id, code=payload.code)
    except ValueError as exc:
        raise HTTPException(status_code=404, detail=str(exc)) from exc


@router.post("/state", response_model=PythonCodeReviewState)
def get_state_post() -> RedirectResponse:
    """Redirect POST /state to GET for compatibility."""
    return RedirectResponse(url="/state", status_code=303)


app.include_router(router)


def _prioritize_route(path: str, methods: set[str]) -> None:
    """Move a matching custom route ahead of default OpenEnv routes."""
    try:
        for index in range(len(app.router.routes) - 1, -1, -1):
            route = app.router.routes[index]
            route_path = getattr(route, "path", None)
            route_methods = set(getattr(route, "methods", set()) or set())
            if route_path == path and methods.issubset(route_methods):
                app.router.routes.insert(0, app.router.routes.pop(index))
                break
    except Exception:
        pass


_prioritize_route("/health", {"GET"})


def main(host: str = "0.0.0.0", port: int = 8000) -> None:
    """Run the FastAPI application with uvicorn."""
    import uvicorn
    uvicorn.run(
        app,
        host=os.getenv("HOST", host),
        port=int(os.getenv("PORT", str(port))),
    )


if __name__ == "__main__":
    main()