import os
import subprocess
import shutil
import base64
import json
from typing import Optional
from fastapi import FastAPI, UploadFile, File, Request, HTTPException, Form
from fastapi.responses import HTMLResponse
from fastapi.staticfiles import StaticFiles
from fastapi.templating import Jinja2Templates
from ultralytics import YOLO
import cv2
import numpy as np
from pathlib import Path
import uuid
import time
from fastapi import BackgroundTasks
from fastapi.responses import FileResponse

app = FastAPI()

# Setup paths
BASE_DIR = Path(__file__).resolve().parent
UPLOAD_DIR = BASE_DIR / "uploads"
MODEL_DIR = UPLOAD_DIR / "models"
VIDEO_DIR = UPLOAD_DIR / "videos"
RESULT_DIR = UPLOAD_DIR / "results"
TEMP_DIR = UPLOAD_DIR / "temp"

for d in [MODEL_DIR, TEMP_DIR, VIDEO_DIR, RESULT_DIR]:
    d.mkdir(parents=True, exist_ok=True)

# Global model state and task tracking
current_model = None
model_name = ""
video_tasks = {} # task_id: {"progress": P, "status": S, "result": R}

app.mount("/static", StaticFiles(directory=str(BASE_DIR / "static")), name="static")
templates = Jinja2Templates(directory=str(BASE_DIR / "templates"))

@app.get("/", response_class=HTMLResponse)
async def read_root(request: Request):
    return templates.TemplateResponse(
        request=request,
        name="index.html",
        context={
            "model_loaded": current_model is not None, 
            "model_name": model_name
        }
    )

@app.post("/upload-model")
async def upload_model(file: UploadFile = File(...)):
    global current_model, model_name
    if not file.filename.endswith(".pt"):
        raise HTTPException(status_code=400, detail="Only .pt files are supported")
    
    file_path = MODEL_DIR / file.filename
    with open(file_path, "wb") as buffer:
        shutil.copyfileobj(file.file, buffer)
    
    try:
        current_model = YOLO(str(file_path))
        model_name = file.filename
        return {"status": "success", "message": f"Model {model_name} loaded successfully"}
    except Exception as e:
        if os.path.exists(file_path):
            os.remove(file_path)
        raise HTTPException(status_code=500, detail=f"Failed to load model: {str(e)}")

def apply_roi_filter(results, roi, img_w, img_h):
    if not roi:
        return results, []

    x1_roi = int(roi['x1'] * img_w / 100)
    y1_roi = int(roi['y1'] * img_h / 100)
    x2_roi = int(roi['x2'] * img_w / 100)
    y2_roi = int(roi['y2'] * img_h / 100)

    indices = []
    for i, box in enumerate(results.boxes):
        bx1, by1, bx2, by2 = box.xyxy[0].tolist()
        bcx = (bx1 + bx2) / 2
        bcy = (by1 + by2) / 2
        
        if x1_roi <= bcx <= x2_roi and y1_roi <= bcy <= y2_roi:
            indices.append(i)
    
    results.boxes = results.boxes[indices]
    return results, [x1_roi, y1_roi, x2_roi, y2_roi]

def draw_roi_on_img(img, roi_coords):
    if not roi_coords:
        return img
    x1, y1, x2, y2 = roi_coords
    # Draw a dashed or semi-transparent rectangle for ROI
    overlay = img.copy()
    cv2.rectangle(overlay, (x1, y1), (x2, y2), (0, 255, 255), 2)
    cv2.putText(overlay, "ROI ZONE", (x1 + 5, y1 + 25), cv2.FONT_HERSHEY_SIMPLEX, 0.7, (0, 255, 255), 2)
    return cv2.addWeighted(overlay, 0.6, img, 0.4, 0)

@app.post("/inference")
async def run_inference(
    file: UploadFile = File(...),
    conf_min: float = Form(0.25),
    conf_max: float = Form(1.0),
    roi: Optional[str] = Form(None)
):
    global current_model
    if current_model is None:
        raise HTTPException(status_code=400, detail="No model loaded. Please upload a model first.")
    
    # Parse ROI if present
    roi_data = json.loads(roi) if roi else None
    
    # Read image
    contents = await file.read()
    nparr = np.frombuffer(contents, np.uint8)
    img = cv2.imdecode(nparr, cv2.IMREAD_COLOR)
    
    if img is None:
        raise HTTPException(status_code=400, detail="Invalid image file")

    h, w = img.shape[:2]

    # Run inference with min threshold
    results = current_model(img, conf=conf_min)[0]
    
    # Apply max confidence filtering
    if conf_max < 1.0:
        indices = [i for i, box in enumerate(results.boxes) if float(box.conf[0]) <= conf_max]
        results.boxes = results.boxes[indices]

    # Apply ROI filtering
    results, roi_coords = apply_roi_filter(results, roi_data, w, h)
    
    # Draw results
    annotated_img = results.plot()
    
    # Draw ROI box
    annotated_img = draw_roi_on_img(annotated_img, roi_coords)
    
    # Encode to base64
    _, buffer = cv2.imencode('.jpg', annotated_img)
    img_str = base64.b64encode(buffer).decode('utf-8')
    
    # Extract box info
    boxes = []
    for box in results.boxes:
        boxes.append({
            "cls": int(box.cls[0]),
            "conf": float(box.conf[0]),
            "xyxy": box.xyxy[0].tolist()
        })
    
    return {
        "status": "success",
        "image": f"data:image/jpeg;base64,{img_str}",
        "count": len(results.boxes),
        "boxes": boxes
    }

def process_video_task(task_id: str, input_path: str, output_path: str, conf_min: float, conf_max: float, roi: Optional[dict]):
    global current_model, video_tasks
    
    # Temporary path for OpenCV output
    temp_output = str(RESULT_DIR / f"temp_{task_id}.mp4")
    
    try:
        cap = cv2.VideoCapture(input_path)
        if not cap.isOpened():
            video_tasks[task_id]["status"] = "error"
            video_tasks[task_id]["message"] = "Could not open video file"
            return

        fps = cap.get(cv2.CAP_PROP_FPS)
        w = int(cap.get(cv2.CAP_PROP_FRAME_WIDTH))
        h = int(cap.get(cv2.CAP_PROP_FRAME_HEIGHT))
        total_frames = int(cap.get(cv2.CAP_PROP_FRAME_COUNT))
        
        # Using mp4v for the intermediate file
        fourcc = cv2.VideoWriter_fourcc(*'mp4v')
        out = cv2.VideoWriter(temp_output, fourcc, fps, (w, h))
        
        frame_count = 0
        while cap.isOpened():
            ret, frame = cap.read()
            if not ret:
                break
            
            # Inference with min threshold
            results = current_model(frame, conf=conf_min)[0]
            
            # Apply max confidence filtering
            if conf_max < 1.0:
                indices = [i for i, box in enumerate(results.boxes) if float(box.conf[0]) <= conf_max]
                results.boxes = results.boxes[indices]

            # Apply ROI filtering
            results, roi_coords = apply_roi_filter(results, roi, w, h)
            
            # Draw results
            annotated_frame = results.plot()
            
            # Draw ROI box
            annotated_frame = draw_roi_on_img(annotated_frame, roi_coords)
            
            out.write(annotated_frame)
            frame_count += 1
            
            # Update progress (0-90% for processing)
            progress = int((frame_count / total_frames) * 90)
            video_tasks[task_id]["progress"] = progress
            
        cap.release()
        out.release()
        
        # Transcode to H.264 for web compatibility
        video_tasks[task_id]["progress"] = 95
        video_tasks[task_id]["status"] = "transcoding"
        
        ffmpeg_cmd = [
            'ffmpeg', '-y', '-i', temp_output,
            '-c:v', 'libx264', '-preset', 'ultrafast', '-crf', '28',
            '-pix_fmt', 'yuv420p', '-c:a', 'aac', '-b:a', '128k',
            output_path
        ]
        
        subprocess.run(ffmpeg_cmd, check=True, capture_output=True)
        
        video_tasks[task_id]["progress"] = 100
        video_tasks[task_id]["status"] = "completed"
        video_tasks[task_id]["result_url"] = f"/video-result/{task_id}"
        
    except Exception as e:
        video_tasks[task_id]["status"] = "error"
        video_tasks[task_id]["message"] = str(e)
    finally:
        # Cleanup files
        if os.path.exists(input_path):
            os.remove(input_path)
        if os.path.exists(temp_output):
            os.remove(temp_output)

@app.post("/inference-video")
async def run_video_inference(
    background_tasks: BackgroundTasks, 
    file: UploadFile = File(...),
    conf_min: float = Form(0.25),
    conf_max: float = Form(1.0),
    roi: Optional[str] = Form(None)
):
    global current_model, video_tasks
    if current_model is None:
        raise HTTPException(status_code=400, detail="No model loaded. Please upload a model first.")
    
    # Parse ROI
    roi_data = json.loads(roi) if roi else None
    
    task_id = str(uuid.uuid4())
    input_filename = f"{task_id}_{file.filename}"
    input_path = VIDEO_DIR / input_filename
    output_filename = f"processed_{task_id}.mp4"
    output_path = RESULT_DIR / output_filename
    
    with open(input_path, "wb") as buffer:
        shutil.copyfileobj(file.file, buffer)
    
    video_tasks[task_id] = {
        "progress": 0,
        "status": "processing",
        "filename": file.filename
    }
    
    background_tasks.add_task(process_video_task, task_id, str(input_path), str(output_path), conf_min, conf_max, roi_data)
    
    return {"status": "success", "task_id": task_id}

@app.get("/video-progress/{task_id}")
async def get_video_progress(task_id: str):
    if task_id not in video_tasks:
        raise HTTPException(status_code=404, detail="Task not found")
    return video_tasks[task_id]

@app.get("/video-result/{task_id}")
async def get_video_result(task_id: str):
    output_filename = f"processed_{task_id}.mp4"
    output_path = RESULT_DIR / output_filename
    if not output_path.exists():
        raise HTTPException(status_code=404, detail="Result not found or still processing")
    return FileResponse(path=output_path, filename=f"inference_{task_id}.mp4", media_type="video/mp4")

if __name__ == "__main__":
    import uvicorn
    # Use port from environment variable for Hugging Face compatibility (default 7860)
    port = int(os.environ.get("PORT", 7860))
    uvicorn.run(app, host="0.0.0.0", port=port)