import os
from datetime import datetime
from flask import current_app
from flask_login import current_user


class LogHelper:
    @staticmethod
    def log_action(action, details=""):
        """Add a log entry."""
        log_data = LogData()
        log_data.add_log(action, details)


class LogData:

    def __init__(self):
        self.filepath = os.path.join(current_app.root_path, 'activity.log')
        self.timestamp = datetime.now().strftime("%Y-%m-%d %H:%M:%S")
        self.user = getattr(current_user, "cn", None) \
                    or getattr(current_user, "username", None) \
                    or getattr(current_user, "sAMAccountName", "Unknown")


    def add_log(self, action, details=""):
        """Create/Add a log entry."""
        with open(self.filepath, "a", encoding="utf-8") as f:
            f.write(
                f"Timestamp: {self.timestamp} | "
                f"User: {self.user} | "
                f"Action: {action} | "
                f"Details: {details}\n"
            )

    def get_all_logs(self):
        """Read all logs."""
        logs = []
        if os.path.exists(self.filepath):
            with open(self.filepath, 'r', encoding="utf-8") as f:
                for line in f:
                    parts = line.strip().split(" | ")
                    if len(parts) == 4:
                        logs.append({
                            "timestamp": parts[0].split(":", 1)[1].strip(),
                            "user": parts[1].split(":", 1)[1].strip(),
                            "action": parts[2].split(":", 1)[1].strip(),
                            "details": parts[3].split(":", 1)[1].strip()
                        })
        return logs

    def get_filtered_logs(self, start_date=None, end_date=None, user_name=None):
        """Filter logs by date and/or user."""
        logs = self.get_all_logs()

        # Filter by date
        if start_date or end_date:
            start_dt = datetime.strptime(start_date, "%Y-%m-%d") if start_date else datetime.min
            end_dt = datetime.strptime(end_date, "%Y-%m-%d") if end_date else datetime.max
            logs = [
                log for log in logs
                if start_dt <= datetime.strptime(log["timestamp"], "%Y-%m-%d %H:%M:%S") <= end_dt
            ]

        # Filter by username
        if user_name:
            logs = [log for log in logs if user_name.lower() in log.get("user", "").lower()]

        return logs

    def update_log(self, index, action=None, details=None):
        """Update a specific log entry by index (0-based)."""
        logs = self.get_all_logs()
        if 0 <= index < len(logs):
            if action:
                logs[index]["action"] = action
            if details:
                logs[index]["details"] = details
            self._rewrite_logs_file(logs)
            return True
        return False

    def delete_log(self, index):
        """Delete a specific log entry by index (0-based)."""
        logs = self.get_all_logs()
        if 0 <= index < len(logs):
            logs.pop(index)
            self._rewrite_logs_file(logs)
            return True
        return False

    # ------------------- INTERNAL HELPER -------------------

    def _rewrite_logs_file(self, logs):
        """Overwrite the log file with current logs."""
        with open(self.filepath, "w", encoding="utf-8") as f:
            for log in logs:
                f.write(
                    f"Timestamp: {log['timestamp']} | "
                    f"User: {log['user']} | "
                    f"Action: {log['action']} | "
                    f"Details: {log['details']}\n"
                )