from fastapi import FastAPI, WebSocket, WebSocketDisconnect, HTTPException, Request
from fastapi.staticfiles import StaticFiles
from fastapi.responses import FileResponse
from fastapi.middleware.cors import CORSMiddleware
from pydantic import BaseModel
from typing import Optional, List, Any
import base64
import cv2
import numpy as np
import aiosqlite
import json
from datetime import datetime, timedelta
import math
import os
from pathlib import Path

# Initialize FastAPI app
app = FastAPI(title="Focus Guard API")

# Add CORS middleware
app.add_middleware(
    CORSMiddleware,
    allow_origins=["*"],
    allow_credentials=True,
    allow_methods=["*"],
    allow_headers=["*"],
)

# Global variables
model = None
db_path = "focus_guard.db"

# ================ DATABASE MODELS ================

async def init_database():
    """Initialize SQLite database with required tables"""
    async with aiosqlite.connect(db_path) as db:
        # FocusSessions table
        await db.execute("""
            CREATE TABLE IF NOT EXISTS focus_sessions (
                id INTEGER PRIMARY KEY AUTOINCREMENT,
                start_time TIMESTAMP NOT NULL,
                end_time TIMESTAMP,
                duration_seconds INTEGER DEFAULT 0,
                focus_score REAL DEFAULT 0.0,
                total_frames INTEGER DEFAULT 0,
                focused_frames INTEGER DEFAULT 0,
                created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP
            )
        """)

        # FocusEvents table
        await db.execute("""
            CREATE TABLE IF NOT EXISTS focus_events (
                id INTEGER PRIMARY KEY AUTOINCREMENT,
                session_id INTEGER NOT NULL,
                timestamp TIMESTAMP NOT NULL,
                is_focused BOOLEAN NOT NULL,
                confidence REAL NOT NULL,
                detection_data TEXT,
                FOREIGN KEY (session_id) REFERENCES focus_sessions (id)
            )
        """)

        # UserSettings table
        await db.execute("""
            CREATE TABLE IF NOT EXISTS user_settings (
                id INTEGER PRIMARY KEY CHECK (id = 1),
                sensitivity INTEGER DEFAULT 6,
                notification_enabled BOOLEAN DEFAULT 1,
                notification_threshold INTEGER DEFAULT 30,
                frame_rate INTEGER DEFAULT 30,
                model_name TEXT DEFAULT 'yolov8n.pt'
            )
        """)

        # Insert default settings if not exists
        await db.execute("""
            INSERT OR IGNORE INTO user_settings (id, sensitivity, notification_enabled, notification_threshold, frame_rate, model_name)
            VALUES (1, 6, 1, 30, 30, 'yolov8n.pt')
        """)

        await db.commit()

# ================ PYDANTIC MODELS ================

class SessionCreate(BaseModel):
    pass

class SessionEnd(BaseModel):
    session_id: int

class SettingsUpdate(BaseModel):
    sensitivity: Optional[int] = None
    notification_enabled: Optional[bool] = None
    notification_threshold: Optional[int] = None
    frame_rate: Optional[int] = None

# ================ YOLO MODEL LOADING ================

def load_yolo_model():
    """Load YOLOv8 model with optimizations for CPU"""
    global model
    try:
        # Fix PyTorch 2.6+ weights_only issue
        os.environ['TORCH_LOAD_WEIGHTS_ONLY'] = '0'

        import torch
        if hasattr(torch.serialization, 'add_safe_globals'):
            try:
                from ultralytics.nn.tasks import DetectionModel
                import torch.nn as nn
                torch.serialization.add_safe_globals([
                    DetectionModel,
                    nn.modules.container.Sequential,
                ])
            except Exception as e:
                print(f"  Safe globals setup: {e}")

        from ultralytics import YOLO

        model_path = "models/yolov8n.pt"

        if not os.path.exists(model_path):
            print(f"Model file {model_path} not found, downloading yolov8n.pt...")
            model_path = "yolov8n.pt"

        model = YOLO(model_path)

        try:
            model.fuse()
            print("[OK] Model layers fused for optimization")
        except Exception as e:
            print(f"  Model fusion skipped: {e}")

        # Warm up
        print("Warming up model...")
        dummy_img = np.zeros((416, 416, 3), dtype=np.uint8)
        model(dummy_img, imgsz=416, conf=0.4, iou=0.45, max_det=5, classes=[0], verbose=False)

        print("[OK] YOLOv8 model loaded and warmed up successfully")
        return True
    except Exception as e:
        print(f"[ERROR] Failed to load YOLOv8 model: {e}")
        import traceback
        traceback.print_exc()
        return False

# ================ FOCUS DETECTION ALGORITHM ================

def is_user_focused(detections, frame_shape, sensitivity=6):
    persons = [d for d in detections if d.get('class') == 0]

    if not persons:
        return False, 0.0, {'reason': 'no_person', 'count': 0}

    best_person = max(persons, key=lambda x: x.get('confidence', 0))
    bbox = best_person['bbox']
    conf = best_person['confidence']

    base_threshold = 0.8
    sensitivity_adjustment = (sensitivity - 6) * 0.02
    confidence_threshold = base_threshold + sensitivity_adjustment
    confidence_threshold = max(0.5, min(0.95, confidence_threshold))

    is_focused = conf >= confidence_threshold

    h, w = frame_shape[0], frame_shape[1]
    bbox_center_x = (bbox[0] + bbox[2]) / 2
    bbox_center_y = (bbox[1] + bbox[3]) / 2

    center_x_norm = bbox_center_x / w if w > 0 else 0.5
    center_y_norm = bbox_center_y / h if h > 0 else 0.5

    in_frame = (0.2 <= center_x_norm <= 0.8) and (0.15 <= center_y_norm <= 0.85)

    position_factor = 1.0 if in_frame else 0.7
    final_score = conf * position_factor

    if len(persons) > 1:
        final_score *= 0.9
        reason = f"person_detected_multi_{len(persons)}"
    else:
        reason = "person_detected" if is_focused else "low_confidence"

    metadata = {
        'bbox': bbox,
        'detection_confidence': round(conf, 3),
        'confidence_threshold': round(confidence_threshold, 3),
        'center_position': [round(center_x_norm, 3), round(center_y_norm, 3)],
        'in_frame': in_frame,
        'person_count': len(persons),
        'reason': reason
    }

    return is_focused and in_frame, final_score, metadata

def parse_yolo_results(results):
    detections = []
    if results and len(results) > 0:
        result = results[0]
        boxes = result.boxes
        if boxes is not None and len(boxes) > 0:
            for box in boxes:
                xyxy = box.xyxy[0].cpu().numpy()
                conf = float(box.conf[0].cpu().numpy())
                cls = int(box.cls[0].cpu().numpy())
                detection = {
                    'bbox': [float(x) for x in xyxy],
                    'confidence': conf,
                    'class': cls,
                    'class_name': result.names[cls] if hasattr(result, 'names') else str(cls)
                }
                detections.append(detection)
    return detections

# ================ DATABASE OPERATIONS ================

async def create_session():
    async with aiosqlite.connect(db_path) as db:
        cursor = await db.execute(
            "INSERT INTO focus_sessions (start_time) VALUES (?)",
            (datetime.now().isoformat(),)
        )
        await db.commit()
        return cursor.lastrowid

async def end_session(session_id: int):
    async with aiosqlite.connect(db_path) as db:
        cursor = await db.execute(
            "SELECT start_time, total_frames, focused_frames FROM focus_sessions WHERE id = ?",
            (session_id,)
        )
        row = await cursor.fetchone()

        if not row:
            return None

        start_time_str, total_frames, focused_frames = row
        start_time = datetime.fromisoformat(start_time_str)
        end_time = datetime.now()
        duration = (end_time - start_time).total_seconds()
        focus_score = focused_frames / total_frames if total_frames > 0 else 0.0

        await db.execute("""
            UPDATE focus_sessions
            SET end_time = ?, duration_seconds = ?, focus_score = ?
            WHERE id = ?
        """, (end_time.isoformat(), int(duration), focus_score, session_id))

        await db.commit()

        return {
            'session_id': session_id,
            'start_time': start_time_str,
            'end_time': end_time.isoformat(),
            'duration_seconds': int(duration),
            'focus_score': round(focus_score, 3),
            'total_frames': total_frames,
            'focused_frames': focused_frames
        }

async def store_focus_event(session_id: int, is_focused: bool, confidence: float, metadata: dict):
    async with aiosqlite.connect(db_path) as db:
        await db.execute("""
            INSERT INTO focus_events (session_id, timestamp, is_focused, confidence, detection_data)
            VALUES (?, ?, ?, ?, ?)
        """, (session_id, datetime.now().isoformat(), is_focused, confidence, json.dumps(metadata)))

        await db.execute(f"""
            UPDATE focus_sessions
            SET total_frames = total_frames + 1,
                focused_frames = focused_frames + {1 if is_focused else 0}
            WHERE id = ?
        """, (session_id,))
        await db.commit()

# ================ STARTUP/SHUTDOWN ================

@app.on_event("startup")
async def startup_event():
    print(" Starting Focus Guard API...")
    await init_database()
    print("[OK] Database initialized")
    load_yolo_model()

@app.on_event("shutdown")
async def shutdown_event():
    print(" Shutting down Focus Guard API...")

# ================ WEBSOCKET ================

@app.websocket("/ws/video")
async def websocket_endpoint(websocket: WebSocket):
    await websocket.accept()
    session_id = None
    frame_count = 0
    last_inference_time = 0
    min_inference_interval = 0.1

    try:
        async with aiosqlite.connect(db_path) as db:
            cursor = await db.execute("SELECT sensitivity FROM user_settings WHERE id = 1")
            row = await cursor.fetchone()
            sensitivity = row[0] if row else 6

        while True:
            data = await websocket.receive_json()

            if data['type'] == 'frame':
                from time import time
                current_time = time()
                if current_time - last_inference_time < min_inference_interval:
                    await websocket.send_json({'type': 'ack', 'frame_count': frame_count})
                    continue
                last_inference_time = current_time

                try:
                    img_data = base64.b64decode(data['image'])
                    nparr = np.frombuffer(img_data, np.uint8)
                    frame = cv2.imdecode(nparr, cv2.IMREAD_COLOR)

                    if frame is None: continue
                    frame = cv2.resize(frame, (640, 480))

                    if model is not None:
                        results = model(frame, imgsz=416, conf=0.4, iou=0.45, max_det=5, classes=[0], verbose=False)
                        detections = parse_yolo_results(results)
                    else:
                        detections = []

                    is_focused, confidence, metadata = is_user_focused(detections, frame.shape, sensitivity)

                    if session_id:
                        await store_focus_event(session_id, is_focused, confidence, metadata)

                    await websocket.send_json({
                        'type': 'detection',
                        'focused': is_focused,
                        'confidence': round(confidence, 3),
                        'detections': detections,
                        'frame_count': frame_count
                    })
                    frame_count += 1
                except Exception as e:
                    print(f"Error processing frame: {e}")
                    await websocket.send_json({'type': 'error', 'message': str(e)})

            elif data['type'] == 'start_session':
                session_id = await create_session()
                await websocket.send_json({'type': 'session_started', 'session_id': session_id})

            elif data['type'] == 'end_session':
                if session_id:
                    summary = await end_session(session_id)
                    await websocket.send_json({'type': 'session_ended', 'summary': summary})
                    session_id = None

    except WebSocketDisconnect:
        if session_id: await end_session(session_id)
    except Exception as e:
        if websocket.client_state.value == 1: await websocket.close()

# ================ API ENDPOINTS ================

@app.post("/api/sessions/start")
async def api_start_session():
    session_id = await create_session()
    return {"session_id": session_id}

@app.post("/api/sessions/end")
async def api_end_session(data: SessionEnd):
    summary = await end_session(data.session_id)
    if not summary: raise HTTPException(status_code=404, detail="Session not found")
    return summary

@app.get("/api/sessions")
async def get_sessions(filter: str = "all", limit: int = 50, offset: int = 0):
    async with aiosqlite.connect(db_path) as db:
        db.row_factory = aiosqlite.Row

        # NEW: If importing/exporting all, remove limit if special flag or high limit
        # For simplicity: if limit is -1, return all
        limit_clause = "LIMIT ? OFFSET ?"
        params = []
        
        base_query = "SELECT * FROM focus_sessions"
        where_clause = ""
        
        if filter == "today":
            date_filter = datetime.now().replace(hour=0, minute=0, second=0, microsecond=0)
            where_clause = " WHERE start_time >= ?"
            params.append(date_filter.isoformat())
        elif filter == "week":
            date_filter = datetime.now() - timedelta(days=7)
            where_clause = " WHERE start_time >= ?"
            params.append(date_filter.isoformat())
        elif filter == "month":
            date_filter = datetime.now() - timedelta(days=30)
            where_clause = " WHERE start_time >= ?"
            params.append(date_filter.isoformat())
        elif filter == "all":
            # Just ensure we only get completed sessions or all sessions
            where_clause = " WHERE end_time IS NOT NULL"

        query = f"{base_query}{where_clause} ORDER BY start_time DESC"
        
        # Handle Limit for Exports
        if limit == -1: 
            # No limit clause for export
            pass
        else:
            query += f" {limit_clause}"
            params.extend([limit, offset])

        cursor = await db.execute(query, tuple(params))
        rows = await cursor.fetchall()
        return [dict(row) for row in rows]

# --- NEW: Import Endpoint ---
@app.post("/api/import")
async def import_sessions(sessions: List[dict]):
    count = 0
    try:
        async with aiosqlite.connect(db_path) as db:
            for session in sessions:
                # Use .get() to handle potential missing fields from older versions or edits
                await db.execute("""
                    INSERT INTO focus_sessions (start_time, end_time, duration_seconds, focus_score, total_frames, focused_frames, created_at)
                    VALUES (?, ?, ?, ?, ?, ?, ?)
                """, (
                    session.get('start_time'),
                    session.get('end_time'),
                    session.get('duration_seconds', 0),
                    session.get('focus_score', 0.0),
                    session.get('total_frames', 0),
                    session.get('focused_frames', 0),
                    session.get('created_at', session.get('start_time'))
                ))
                count += 1
            await db.commit()
        return {"status": "success", "count": count}
    except Exception as e:
        print(f"Import Error: {e}")
        return {"status": "error", "message": str(e)}

# --- NEW: Clear History Endpoint ---
@app.delete("/api/history")
async def clear_history():
    try:
        async with aiosqlite.connect(db_path) as db:
            # Delete events first (foreign key good practice)
            await db.execute("DELETE FROM focus_events")
            await db.execute("DELETE FROM focus_sessions")
            await db.commit()
        return {"status": "success", "message": "History cleared"}
    except Exception as e:
        return {"status": "error", "message": str(e)}

@app.get("/api/sessions/{session_id}")
async def get_session(session_id: int):
    async with aiosqlite.connect(db_path) as db:
        db.row_factory = aiosqlite.Row
        cursor = await db.execute("SELECT * FROM focus_sessions WHERE id = ?", (session_id,))
        row = await cursor.fetchone()
        if not row: raise HTTPException(status_code=404, detail="Session not found")
        session = dict(row)
        cursor = await db.execute("SELECT * FROM focus_events WHERE session_id = ? ORDER BY timestamp", (session_id,))
        events = [dict(r) for r in await cursor.fetchall()]
        session['events'] = events
        return session

@app.get("/api/settings")
async def get_settings():
    async with aiosqlite.connect(db_path) as db:
        db.row_factory = aiosqlite.Row
        cursor = await db.execute("SELECT * FROM user_settings WHERE id = 1")
        row = await cursor.fetchone()
        if row: return dict(row)
        else: return {'sensitivity': 6, 'notification_enabled': True, 'notification_threshold': 30, 'frame_rate': 30, 'model_name': 'yolov8n.pt'}

@app.put("/api/settings")
async def update_settings(settings: SettingsUpdate):
    async with aiosqlite.connect(db_path) as db:
        cursor = await db.execute("SELECT id FROM user_settings WHERE id = 1")
        exists = await cursor.fetchone()
        if not exists:
            await db.execute("INSERT INTO user_settings (id, sensitivity) VALUES (1, 6)")
            await db.commit()

        updates = []
        params = []
        if settings.sensitivity is not None:
            updates.append("sensitivity = ?")
            params.append(max(1, min(10, settings.sensitivity)))
        if settings.notification_enabled is not None:
            updates.append("notification_enabled = ?")
            params.append(settings.notification_enabled)
        if settings.notification_threshold is not None:
            updates.append("notification_threshold = ?")
            params.append(max(5, min(300, settings.notification_threshold)))
        if settings.frame_rate is not None:
            updates.append("frame_rate = ?")
            params.append(max(5, min(60, settings.frame_rate)))

        if updates:
            query = f"UPDATE user_settings SET {', '.join(updates)} WHERE id = 1"
            await db.execute(query, params)
            await db.commit()
        return {"status": "success", "updated": len(updates) > 0}

@app.get("/api/stats/summary")
async def get_stats_summary():
    async with aiosqlite.connect(db_path) as db:
        cursor = await db.execute("SELECT COUNT(*) FROM focus_sessions WHERE end_time IS NOT NULL")
        total_sessions = (await cursor.fetchone())[0]
        cursor = await db.execute("SELECT SUM(duration_seconds) FROM focus_sessions WHERE end_time IS NOT NULL")
        total_focus_time = (await cursor.fetchone())[0] or 0
        cursor = await db.execute("SELECT AVG(focus_score) FROM focus_sessions WHERE end_time IS NOT NULL")
        avg_focus_score = (await cursor.fetchone())[0] or 0.0
        cursor = await db.execute("SELECT DISTINCT DATE(start_time) as session_date FROM focus_sessions WHERE end_time IS NOT NULL ORDER BY session_date DESC")
        dates = [row[0] for row in await cursor.fetchall()]

        streak_days = 0
        if dates:
            current_date = datetime.now().date()
            for i, date_str in enumerate(dates):
                session_date = datetime.fromisoformat(date_str).date()
                expected_date = current_date - timedelta(days=i)
                if session_date == expected_date: streak_days += 1
                else: break
        return {
            'total_sessions': total_sessions,
            'total_focus_time': int(total_focus_time),
            'avg_focus_score': round(avg_focus_score, 3),
            'streak_days': streak_days
        }

@app.get("/health")
async def health_check():
    return {"status": "healthy", "model_loaded": model is not None, "database": os.path.exists(db_path)}

# ================ STATIC FILES (SPA SUPPORT) ================

# 1. Mount the assets folder (JS/CSS built by Vite/React)
if os.path.exists("static/assets"):
    app.mount("/assets", StaticFiles(directory="static/assets"), name="assets")

# 2. Catch-all route for SPA (React Router)
# This ensures that if you refresh /customise, it serves index.html instead of 404
@app.get("/{full_path:path}")
async def serve_react_app(full_path: str, request: Request):
    # Skip API and WS routes
    if full_path.startswith("api") or full_path.startswith("ws"):
        raise HTTPException(status_code=404, detail="Not Found")
    
    # Serve index.html for any other route
    if os.path.exists("static/index.html"):
        return FileResponse("static/index.html")
    else:
        return {"message": "React app not found. Please run 'npm run build' and copy dist to static."}