import os
from flask import Blueprint, jsonify, request
from backend.core.decorators import get_current_user
from backend.core.monitoring import collect_all_metrics
from backend.services.alert_service import check_resources_and_alert

monitoring_bp = Blueprint("monitoring", __name__)

@monitoring_bp.route("/api/admin/metrics", methods=["GET"])
def get_metrics():
    """
    Get detailed system metrics and statistics.
    Access is restricted to admin via X-Admin-Key header or logged-in 'admin' user.
    """
    # Authorization checks
    is_admin = False
    
    # 1. Check for secret X-Admin-Key in request headers
    admin_key = request.headers.get("X-Admin-Key")
    expected_key = os.environ.get("ADMIN_PAYMENT_KEY", "LYVUHA_ADMIN_2026")
    if admin_key and admin_key == expected_key:
        is_admin = True
        
    # 2. Check logged-in user session/token
    if not is_admin:
        current_user = get_current_user()
        if current_user and current_user.get("username") == "admin":
            is_admin = True
            
    if not is_admin:
        return jsonify({"error": "Unauthorized admin access required"}), 403
        
    try:
        # Collect system statistics and details
        metrics = collect_all_metrics()
        
        # Trigger checks and alerts if RAM or Disk usage is critical
        check_resources_and_alert()
        
        return jsonify({
            "success": True,
            "metrics": metrics
        }), 200
    except Exception as e:
        return jsonify({
            "success": False,
            "error": f"Failed to retrieve system metrics: {str(e)}"
        }), 500


@monitoring_bp.route("/api/admin/logs", methods=["GET"])
def get_logs():
    """
    Get or download application logs.
    Access is restricted to admin via X-Admin-Key header or logged-in 'admin' user.
    """
    is_admin = False
    
    # 1. Check for secret X-Admin-Key in request headers
    admin_key = request.headers.get("X-Admin-Key")
    expected_key = os.environ.get("ADMIN_PAYMENT_KEY", "LYVUHA_ADMIN_2026")
    if admin_key and admin_key == expected_key:
        is_admin = True
        
    # 2. Check logged-in user session/token
    if not is_admin:
        current_user = get_current_user()
        if current_user and current_user.get("username") == "admin":
            is_admin = True
            
    if not is_admin:
        return jsonify({"error": "Unauthorized admin access required"}), 403

    from backend.config import Config
    log_path = os.path.join(Config.ROOT_DIR, "logs", "app.log")

    # Handle file download option
    if request.args.get("download") == "true":
        if not os.path.exists(log_path):
            return jsonify({"error": "Log file does not exist"}), 404
        from flask import send_file
        return send_file(log_path, as_attachment=True, download_name="app.log")

    # Handle standard retrieval
    lines_count = request.args.get("lines", default=100, type=int)
    lines_count = max(1, min(lines_count, 2000))

    if not os.path.exists(log_path):
        return jsonify({
            "success": True,
            "lines_returned": 0,
            "logs": [],
            "message": "Log file not found."
        }), 200

    try:
        from collections import deque
        with open(log_path, "r", encoding="utf-8", errors="ignore") as f:
            last_lines = list(deque(f, maxlen=lines_count))
        
        return jsonify({
            "success": True,
            "lines_returned": len(last_lines),
            "logs": last_lines
        }), 200
    except Exception as e:
        return jsonify({
            "success": False,
            "error": f"Failed to read logs: {str(e)}"
        }), 500


@monitoring_bp.route("/api/admin/profiler", methods=["GET"])
def get_profiler_stats():
    """
    Get recent request profiles with latency breakdown (Total, DB, External, CPU).
    Access is restricted to admin via X-Admin-Key header or logged-in 'admin' user.
    """
    is_admin = False
    admin_key = request.headers.get("X-Admin-Key")
    expected_key = os.environ.get("ADMIN_PAYMENT_KEY", "LYVUHA_ADMIN_2026")
    if admin_key and admin_key == expected_key:
        is_admin = True
        
    if not is_admin:
        current_user = get_current_user()
        if current_user and current_user.get("username") == "admin":
            is_admin = True
            
    if not is_admin:
        return jsonify({"error": "Unauthorized admin access required"}), 403

    try:
        from backend.core.profiler import get_recent_profiles
        profiles = get_recent_profiles()
        return jsonify({
            "success": True,
            "count": len(profiles),
            "profiles": profiles
        }), 200
    except Exception as e:
        return jsonify({
            "success": False,
            "error": f"Failed to retrieve profiler stats: {str(e)}"
        }), 500


@monitoring_bp.route("/api/logs/error", methods=["POST", "OPTIONS"])
def log_frontend_error():
    """
    Receive fatal crash reports from the Frontend ErrorBoundary
    and instantly send an email alert to the admin.
    """
    if request.method == "OPTIONS":
        return jsonify({}), 200
        
    try:
        data = request.json or {}
        message = data.get("message", "Unknown Error")
        stack = data.get("stack", "No stack trace provided.")
        url = data.get("url", "Unknown URL")
        user_agent = data.get("userAgent", "Unknown Browser")
        time = data.get("time", "Unknown Time")

        html_content = f"""
        <div style="font-family: Arial, sans-serif; max-width: 600px; margin: 0 auto; border: 1px solid #e2e8f0; border-radius: 8px; overflow: hidden;">
            <div style="background-color: #dc2626; color: white; padding: 15px 20px;">
                <h2 style="margin: 0;">🚨 Tiên Hiệp AI - Frontend Crash Alert</h2>
            </div>
            <div style="padding: 20px; background-color: #f8fafc;">
                <p><strong>Thời gian:</strong> {time}</p>
                <p><strong>URL phát sinh lỗi:</strong> <a href="{url}">{url}</a></p>
                <p><strong>Trình duyệt:</strong> {user_agent}</p>
                <hr style="border: none; border-top: 1px solid #cbd5e1; margin: 20px 0;" />
                <h3 style="color: #b91c1c; margin-bottom: 10px;">Lỗi (Error Message):</h3>
                <div style="background: #fee2e2; border: 1px solid #f87171; padding: 12px; border-radius: 6px; color: #991b1b; font-weight: bold; word-break: break-all;">
                    {message}
                </div>
                <h3 style="color: #334155; margin-top: 20px; margin-bottom: 10px;">Mã Lỗi (Stack Trace):</h3>
                <pre style="background: #1e293b; color: #e2e8f0; padding: 15px; border-radius: 6px; overflow-x: auto; font-size: 13px; line-height: 1.5;">{stack}</pre>
            </div>
        </div>
        """
        
        # Gửi email ngầm (không làm chậm server)
        from backend.services.email_service import send_email_async
        admin_email = os.environ.get("ADMIN_EMAIL", "havucong@lyvuha.com")
        
        send_email_async(
            to_email=admin_email,
            subject=f"[CRASH ALERT] Lỗi nghiêm trọng tại Tiên Hiệp AI ({url})",
            html_content=html_content
        )
        
        return jsonify({"success": True, "message": "Crash report received and email queued."}), 200
    except Exception as e:
        print(f"❌ Failed to process frontend crash log: {e}")
        return jsonify({"success": False, "error": str(e)}), 500