"""FastAPI server for the SQL Repair OpenEnv environment.

Endpoints (all required by the OpenEnv submission validator):
  GET  /health   -> {"status": "ok"}
  GET  /tasks    -> {"tasks": ["task_1", "task_2", "task_3"]}
  POST /reset    -> reset env to a task (body optional, defaults to task_1)
  POST /step     -> apply an action, return observation/reward/done
  POST /grader   -> compute final score for a task (strictly in (0, 1))
  POST /baseline -> run all tasks with the broken queries, return scores

Phase 1 hard requirement: /reset MUST accept an empty POST body.
We achieve that with `Optional[ResetRequest] = Body(default=None)`.

Entry point exposed via [project.scripts] server = "server.app:main".
"""
from __future__ import annotations

import os
from typing import Any, Dict, List, Optional

from fastapi import Body, FastAPI, HTTPException
from fastapi.responses import FileResponse
from fastapi.staticfiles import StaticFiles
from pydantic import BaseModel, Field

from sql_env.env_core import EnvState, MAX_STEPS
from sql_env.grader import grade_task
from sql_env.tasks import TASK_IDS, TASKS

app = FastAPI(
    title="SQL Repair OpenEnv",
    version="0.1.0",
    description=(
        "An OpenEnv environment for SQL query repair. Agents fix broken "
        "SQL queries against a small SQLite schema."
    ),
)

# Single mutable env state instance — the validator runs one session.
_state = EnvState()
_server_dir = os.path.dirname(os.path.abspath(__file__))
_frontend_dist = os.path.abspath(os.path.join(_server_dir, "..", "frontend", "dist"))


# ---------------------------------------------------------------------------
# Pydantic request models
# ---------------------------------------------------------------------------
class ResetRequest(BaseModel):
    task_id: Optional[str] = Field(default=None, description="Task ID to reset to")


class StepAction(BaseModel):
    action_type: str = Field(default="submit_query")
    query: str = Field(default="")


class StepRequest(BaseModel):
    action: Dict[str, Any] = Field(default_factory=dict)


class GraderRequest(BaseModel):
    task_id: Optional[str] = Field(default=None)


class BaselineRequest(BaseModel):
    tasks: Optional[List[str]] = Field(default=None)


# ---------------------------------------------------------------------------
# Endpoints
# ---------------------------------------------------------------------------
@app.get("/health")
def health() -> Dict[str, str]:
    return {"status": "ok"}


@app.get("/api/health")
def health_api() -> Dict[str, str]:
    return health()


@app.get("/tasks")
def list_tasks() -> Dict[str, Any]:
    return {
        "tasks": TASK_IDS,
        "details": [
            {
                "id": TASKS[t]["id"],
                "name": TASKS[t]["name"],
                "difficulty": TASKS[t]["difficulty"],
            }
            for t in TASK_IDS
        ],
    }


@app.get("/api/tasks")
def list_tasks_api() -> Dict[str, Any]:
    return list_tasks()


@app.post("/reset")
def reset(req: Optional[ResetRequest] = Body(default=None)) -> Dict[str, Any]:
    """Reset the environment. Body is optional — defaults to task_1."""
    task_id = req.task_id if (req and req.task_id) else "task_1"
    obs = _state.reset(task_id)
    return obs


@app.post("/api/reset")
def reset_api(req: Optional[ResetRequest] = Body(default=None)) -> Dict[str, Any]:
    return reset(req)


@app.post("/step")
def step(req: Optional[StepRequest] = Body(default=None)) -> Dict[str, Any]:
    """Apply one action to the environment."""
    action: Dict[str, Any] = (req.action if req and req.action else {})
    return _state.step(action)


@app.post("/api/step")
def step_api(req: Optional[StepRequest] = Body(default=None)) -> Dict[str, Any]:
    return step(req)


@app.post("/grader")
def grader(req: Optional[GraderRequest] = Body(default=None)) -> Dict[str, Any]:
    """Return the strict-(0,1) score for the given task."""
    task_id = req.task_id if (req and req.task_id) else (_state.task_id or "task_1")
    score = grade_task(_state, task_id)
    return {"task_id": task_id, "score": float(score)}


@app.post("/api/grader")
def grader_api(req: Optional[GraderRequest] = Body(default=None)) -> Dict[str, Any]:
    return grader(req)


@app.post("/baseline")
def baseline(
    req: Optional[BaselineRequest] = Body(default=None),
) -> Dict[str, Any]:
    """Run all tasks with the broken queries to verify graders work."""
    task_ids = (req.tasks if (req and req.tasks) else None) or list(TASK_IDS)
    out: Dict[str, float] = {}
    for tid in task_ids:
        if tid not in TASKS:
            continue
        local = EnvState()
        local.reset(tid)
        # Submit the broken query as a baseline submission
        local.step({"action_type": "submit_query", "query": TASKS[tid]["broken_query"]})
        out[tid] = float(grade_task(local, tid))
    return {"scores": out, "max_steps": MAX_STEPS}


@app.post("/api/baseline")
def baseline_api(
    req: Optional[BaselineRequest] = Body(default=None),
) -> Dict[str, Any]:
    return baseline(req)


@app.get("/", include_in_schema=False, response_model=None)
def root() -> Any:
    index_file = os.path.join(_frontend_dist, "index.html")
    if os.path.exists(index_file):
        return FileResponse(index_file)
    return {
        "name": "SQL Repair OpenEnv",
        "status": "ok",
        "docs": "/docs",
        "health": "/health",
        "tasks": "/tasks",
    }


if os.path.isdir(_frontend_dist):
    assets_dir = os.path.join(_frontend_dist, "assets")
    if os.path.isdir(assets_dir):
        app.mount("/assets", StaticFiles(directory=assets_dir), name="assets")

    @app.get("/{full_path:path}", include_in_schema=False)
    def spa_fallback(full_path: str) -> FileResponse:
        if full_path.startswith("api/"):
            raise HTTPException(status_code=404, detail="Not Found")

        requested_file = os.path.join(_frontend_dist, full_path)
        if os.path.isfile(requested_file):
            return FileResponse(requested_file)

        index_file = os.path.join(_frontend_dist, "index.html")
        if os.path.isfile(index_file):
            return FileResponse(index_file)

        raise HTTPException(status_code=404, detail="Not Found")


# ---------------------------------------------------------------------------
# Entry point — referenced by [project.scripts] server = "server.app:main"
# ---------------------------------------------------------------------------
def main() -> None:
    """Entry point for `python -m server.app` and the `server` console script."""
    import uvicorn

    host = os.getenv("HOST", "0.0.0.0")
    port = int(os.getenv("PORT", "8000"))
    uvicorn.run(app, host=host, port=port, log_level="info")


if __name__ == "__main__":
    main()