An Expert advisor based on ZigZag

1. Risk Management: Employs an ATR-based Stop Loss and a 1:3 Risk/Reward ratio.
2. Trade Management: Includes a trailing stop mechanism activated after a 300-point profit threshold.

Required Improvements & Fixes
I would like you to address the following technical and strategic issues found in the source code:
1. Resource Management & Data Integrity

1. Handle Cleanup: Implement proper OnDeinit logic to release indicator handles (ZigZag, EMA, ATR), which are currently unmanaged.
2. Data Validation: Improve the CopyBuffer logic to ensure the EA does not execute trades on empty or stale indicator data.

2. Execution Efficiency

1. Position Selection: Replace the current PositionSelectByMagic loop with a more efficient, class-based approach (using CPositionInfo) to reduce overhead during high-volatility price ticks.
2. Slippage & Error Handling: Integrate robust error handling for trade execution and modification, particularly for "small account" environments where spreads may fluctuate.

3. Strategy Refinement

1. ZigZag Repainting Fix: The EA currently trades on the current (forming) ZigZag point (zz[0]). I request that the entry logic be shifted to "confirmed" points (index 1 or 2) to prevent entries based on disappearing signals.
2. Trailing Stop Logic: Standardize point-to-pip conversions to ensure the trailing stop operates correctly across both 4-digit and 5-digit brokers.
   

Deliverables

1. A fully refactored .mq5 file that is modular and ready for backtesting.
2. Clean, commented code following MQL5 best practices.
3. Confirmation that the EA allows only one open position at a time per symbol.

Please review the attached source code and provide an estimate regarding the timeline and cost for these enhancements. I am looking for a robust, production-ready version that can safely handle live market conditions.
Best regards,