from fastapi.staticfiles import StaticFiles
from fastapi import FastAPI, Form
from moviepy.editor import VideoFileClip
from datetime import datetime, timedelta
from pathlib import Path
from PIL import Image
import threading

app = FastAPI(title="Frame Generator")
app.mount("/frames", StaticFiles(directory="frames"), name="frames")

VIDEO_PATH = "demo1.mp4"
FRAME_DIR = Path("frames")
FRAME_STEP = 15
MAX_FRAMES = 4

# Global session state (OK for your current testing)
session = {
    "camera_id": None,
    "start_time": None,
    "date": None,
    "current_index": 0,
    "frames": []
}


def generate_frames_once():
    FRAME_DIR.mkdir(exist_ok=True)

    clip = VideoFileClip(VIDEO_PATH)
    duration = int(clip.duration)

    frames = []

    for i, t in enumerate(range(0, duration, FRAME_STEP)):
        if i >= MAX_FRAMES:
            break

        frame = clip.get_frame(t)
        img = Image.fromarray(frame)

        fname = f"frame_{i:03d}.jpg"
        fpath = FRAME_DIR / fname
        img.save(fpath, "JPEG", quality=90)

        frames.append({
            "index": i,
            "offset": t,
            "path": f"/frames/{fname}"
        })

    clip.close()
    return frames


# Generate frames at startup (ONCE)
@app.on_event("startup")
def startup_event():
    session["frames"] = generate_frames_once()


@app.post("/start")
def start_session(
    camera_id: str = Form(...),
    current_time: str = Form(...)
):
    """
    current_time format: DD-MM-YYYY HH:MM:SS
    """
    start_dt = datetime.strptime(current_time, "%d-%m-%Y %H:%M:%S")

    session["camera_id"] = camera_id
    session["start_time"] = start_dt
    session["date"] = start_dt.strftime("%d-%m-%Y")
    session["current_index"] = 0

    return {
        "status": "started",
        "camera_id": camera_id,
        "date": session["date"],
        "total_frames": len(session["frames"])
    }


@app.get("/next-frame")
def get_next_frame():
    idx = session["current_index"]

    if idx >= len(session["frames"]):
        return {"done": True}

    frame = session["frames"][idx]
    ts = session["start_time"] + timedelta(seconds=frame["offset"])

    session["current_index"] += 1

    return {
        "done": False,
        "frame_index": frame["index"],
        "timestamp": ts.strftime("%H:%M:%S"),
        "image_url": frame["path"]
    }