import logging
import os
import tempfile
import time
from dataclasses import dataclass
from pathlib import Path
from typing import Optional
from uuid import uuid4

from fastapi import BackgroundTasks, FastAPI, File, Form, HTTPException, UploadFile
from fastapi.middleware.cors import CORSMiddleware
from fastapi.responses import FileResponse, HTMLResponse, JSONResponse
import uvicorn

from inference import run_inference
from mission_planner import MissionPlan, get_mission_plan

logging.basicConfig(level=logging.INFO)

app = FastAPI(title="Video Processing Backend")
app.add_middleware(
    CORSMiddleware,
    allow_origins=["*"],
    allow_credentials=True,
    allow_methods=["*"],
    allow_headers=["*"],
    expose_headers=["x-mission-summary"],
)


def _save_upload_to_tmp(upload: UploadFile) -> str:
    suffix = Path(upload.filename or "upload.mp4").suffix or ".mp4"
    fd, path = tempfile.mkstemp(prefix="input_", suffix=suffix, dir="/tmp")
    os.close(fd)
    with open(path, "wb") as buffer:
        data = upload.file.read()
        buffer.write(data)
    return path


def _safe_delete(path: str) -> None:
    try:
        os.remove(path)
    except FileNotFoundError:
        return
    except Exception:
        logging.exception("Failed to remove temporary file: %s", path)


def _schedule_cleanup(background_tasks: BackgroundTasks, path: str) -> None:
    def _cleanup(target: str = path) -> None:
        _safe_delete(target)

    background_tasks.add_task(_cleanup)


@dataclass
class CachedMission:
    prompt: str
    detector: Optional[str]
    latitude: float
    longitude: float
    plan: MissionPlan
    created_at: float


MISSION_CACHE: dict[str, CachedMission] = {}
MISSION_CACHE_TTL_SECONDS = 3600.0


def _prune_mission_cache() -> None:
    now = time.time()
    expired = [
        key
        for key, entry in MISSION_CACHE.items()
        if now - entry.created_at > MISSION_CACHE_TTL_SECONDS
    ]
    for key in expired:
        MISSION_CACHE.pop(key, None)


def _store_mission_plan(
    prompt: str,
    detector: Optional[str],
    plan: MissionPlan,
    latitude: float,
    longitude: float,
) -> str:
    _prune_mission_cache()
    mission_id = uuid4().hex
    MISSION_CACHE[mission_id] = CachedMission(
        prompt=prompt,
        detector=detector,
        latitude=latitude,
        longitude=longitude,
        plan=plan,
        created_at=time.time(),
    )
    return mission_id


def _get_cached_mission(mission_id: str) -> CachedMission:
    _prune_mission_cache()
    entry = MISSION_CACHE.get(mission_id)
    if entry is None:
        raise HTTPException(status_code=404, detail="Mission prompt not found. Please set it again.")
    return entry


def _require_coordinates(
    latitude: Optional[float],
    longitude: Optional[float],
) -> tuple[float, float]:
    if latitude is None or longitude is None:
        raise HTTPException(status_code=400, detail="Mission location coordinates are required.")
    return float(latitude), float(longitude)


def _resolve_mission_plan(
    prompt: Optional[str],
    mission_id: Optional[str],
    latitude: Optional[float],
    longitude: Optional[float],
) -> tuple[MissionPlan, str]:
    if mission_id:
        cached = _get_cached_mission(mission_id)
        return cached.plan, cached.prompt
    normalized_prompt = (prompt or "").strip()
    if not normalized_prompt:
        raise HTTPException(status_code=400, detail="Mission prompt is required.")
    _require_coordinates(latitude, longitude)
    plan = get_mission_plan(normalized_prompt)
    return plan, normalized_prompt


def _validate_inputs(
    video: UploadFile | None,
    prompt: str | None,
    mission_id: Optional[str],
    latitude: Optional[float],
    longitude: Optional[float],
) -> None:
    if video is None:
        raise HTTPException(status_code=400, detail="Video file is required.")
    if mission_id:
        return
    if not prompt:
        raise HTTPException(status_code=400, detail="Mission prompt is required.")
    _require_coordinates(latitude, longitude)


def _location_only_prompt(latitude: float, longitude: float) -> str:
    return (
        "Threat reconnaissance mission. "
        f"Identify and prioritize potential hostile or suspicious object classes around latitude {latitude:.4f}, "
        f"longitude {longitude:.4f}. Consider common threats for this environment when selecting classes."
    )


@app.post("/location_context")
async def location_context(
    latitude: float = Form(...),
    longitude: float = Form(...),
):
    prompt = _location_only_prompt(latitude, longitude)
    try:
        plan = get_mission_plan(prompt)
    except Exception as exc:
        logging.exception("Location-only planning failed.")
        raise HTTPException(status_code=500, detail=str(exc))
    return {
        "mission_plan": plan.to_dict(),
        "location": {"latitude": latitude, "longitude": longitude},
        "prompt_used": prompt,
    }


@app.post("/mission_plan")
async def mission_plan_endpoint(
    prompt: str = Form(...),
    detector: Optional[str] = Form(None),
    latitude: float = Form(...),
    longitude: float = Form(...),
):
    normalized_prompt = (prompt or "").strip()
    if not normalized_prompt:
        raise HTTPException(status_code=400, detail="Prompt is required.")
    try:
        plan = get_mission_plan(normalized_prompt)
    except Exception as exc:
        logging.exception("Mission planning failed.")
        raise HTTPException(status_code=500, detail=str(exc))

    mission_id = _store_mission_plan(normalized_prompt, detector, plan, latitude, longitude)
    return {
        "mission_id": mission_id,
        "mission_plan": plan.to_dict(),
        "location": {"latitude": latitude, "longitude": longitude},
    }


@app.post("/process_video")
async def process_video(
    background_tasks: BackgroundTasks,
    video: UploadFile = File(...),
    prompt: Optional[str] = Form(None),
    mission_id: Optional[str] = Form(None),
    detector: Optional[str] = Form(None),
    latitude: Optional[float] = Form(None),
    longitude: Optional[float] = Form(None),
):
    _validate_inputs(video, prompt, mission_id, latitude, longitude)

    try:
        input_path = _save_upload_to_tmp(video)
    except Exception:
        logging.exception("Failed to save uploaded file.")
        raise HTTPException(status_code=500, detail="Failed to save uploaded video.")
    finally:
        await video.close()

    fd, output_path = tempfile.mkstemp(prefix="output_", suffix=".mp4", dir="/tmp")
    os.close(fd)

    mission_plan, mission_prompt = _resolve_mission_plan(prompt, mission_id, latitude, longitude)
    try:
        output_path, _, _ = run_inference(
            input_path,
            output_path,
            mission_prompt,
            detector_name=detector,
            generate_summary=False,
            mission_plan=mission_plan,
        )
    except ValueError as exc:
        logging.exception("Video decoding failed.")
        _safe_delete(input_path)
        _safe_delete(output_path)
        raise HTTPException(status_code=500, detail=str(exc))
    except Exception as exc:
        logging.exception("Inference failed.")
        _safe_delete(input_path)
        _safe_delete(output_path)
        return JSONResponse(status_code=500, content={"error": str(exc)})

    _schedule_cleanup(background_tasks, input_path)
    _schedule_cleanup(background_tasks, output_path)

    response = FileResponse(
        path=output_path,
        media_type="video/mp4",
        filename="processed.mp4",
    )
    return response


@app.post("/mission_summary")
async def mission_summary(
    video: UploadFile = File(...),
    prompt: Optional[str] = Form(None),
    mission_id: Optional[str] = Form(None),
    detector: Optional[str] = Form(None),
    latitude: Optional[float] = Form(None),
    longitude: Optional[float] = Form(None),
):
    _validate_inputs(video, prompt, mission_id, latitude, longitude)
    mission_plan, mission_prompt = _resolve_mission_plan(prompt, mission_id, latitude, longitude)
    try:
        input_path = _save_upload_to_tmp(video)
    except Exception:
        logging.exception("Failed to save uploaded file.")
        raise HTTPException(status_code=500, detail="Failed to save uploaded video.")
    finally:
        await video.close()

    try:
        _, _, mission_summary = run_inference(
            input_path,
            output_video_path=None,
            mission_prompt=mission_prompt,
            detector_name=detector,
            write_output_video=False,
            generate_summary=True,
            mission_plan=mission_plan,
        )
    except ValueError as exc:
        logging.exception("Video decoding failed.")
        _safe_delete(input_path)
        raise HTTPException(status_code=500, detail=str(exc))
    except Exception as exc:
        logging.exception("Summary generation failed.")
        _safe_delete(input_path)
        return JSONResponse(status_code=500, content={"error": str(exc)})

    _safe_delete(input_path)
    return {
        "mission_plan": mission_plan.to_dict(),
        "mission_summary": mission_summary or "",
    }

if __name__ == "__main__":
    uvicorn.run("app:app", host="0.0.0.0", port=7860, reload=False)
@app.get("/", response_class=HTMLResponse)
async def demo_page() -> str:
    demo_path = Path(__file__).with_name("demo.html")
    try:
        return demo_path.read_text(encoding="utf-8")
    except FileNotFoundError:
        return "<h1>Demo page missing</h1>"