#!/usr/bin/env python

import os
import pathlib
import sys
from datetime import datetime
from dateutil import parser
import datetime
import re
import pytz
from pytz import timezone
from typing import Union
from zoneinfo import ZoneInfo
import email.utils

# Register NetAlertX directories
INSTALL_PATH="/app"
sys.path.extend([f"{INSTALL_PATH}/front/plugins", f"{INSTALL_PATH}/server"])

import conf
from const import *



#-------------------------------------------------------------------------------
# DateTime
#-------------------------------------------------------------------------------

DATETIME_PATTERN = "%Y-%m-%d %H:%M:%S"
DATETIME_REGEX = re.compile(r'^\d{4}-\d{2}-\d{2} \d{2}:\d{2}:\d{2}$')

def timeNowTZ():
    if conf.tz:
        return datetime.datetime.now(conf.tz).replace(microsecond=0)
    else:
        return datetime.datetime.now().replace(microsecond=0)

def timeNow():
    return datetime.datetime.now().replace(microsecond=0)

def get_timezone_offset():    
    now = datetime.datetime.now(conf.tz)
    offset_hours = now.utcoffset().total_seconds() / 3600        
    offset_formatted =  "{:+03d}:{:02d}".format(int(offset_hours), int((offset_hours % 1) * 60))
    return offset_formatted

def timeNowDB(local=True):
    """
    Return the current time (local or UTC) as ISO 8601 for DB storage.
    Safe for SQLite, PostgreSQL, etc.

    Example local: '2025-11-04 18:09:11'
    Example UTC:   '2025-11-04 07:09:11'
    """
    if local:
        try:
            if isinstance(conf.tz, datetime.tzinfo):
                tz = conf.tz
            elif conf.tz:
                tz = ZoneInfo(conf.tz)
            else:
                tz = None
        except Exception:
            tz = None
        return datetime.datetime.now(tz).strftime(DATETIME_PATTERN)
    else:
        return datetime.datetime.now(datetime.UTC).strftime(DATETIME_PATTERN)


#-------------------------------------------------------------------------------
#  Date and time methods
#-------------------------------------------------------------------------------

def normalizeTimeStamp(inputTimeStamp):
    """
    Normalize various timestamp formats into a datetime.datetime object.

    Supports:
    - SQLite-style 'YYYY-MM-DD HH:MM:SS'
    - ISO 8601 'YYYY-MM-DDTHH:MM:SSZ'
    - Epoch timestamps (int or float)
    - datetime.datetime objects (returned as-is)
    - Empty or invalid values (returns None)
    """
    if inputTimeStamp is None:
        return None

    # Already a datetime
    if isinstance(inputTimeStamp, datetime.datetime):
        return inputTimeStamp

    # Epoch timestamp (integer or float)
    if isinstance(inputTimeStamp, (int, float)):
        try:            
            return datetime.datetime.fromtimestamp(inputTimeStamp)
        except (OSError, OverflowError, ValueError):
            return None

    # String formats (SQLite / ISO8601)
    if isinstance(inputTimeStamp, str):
        inputTimeStamp = inputTimeStamp.strip()
        if not inputTimeStamp:
            return None
        try:
            # match the "2025-11-08 14:32:10" format
            pattern = DATETIME_REGEX

            if pattern.match(inputTimeStamp):
                return datetime.datetime.strptime(inputTimeStamp, DATETIME_PATTERN)
            else:
                # Handles SQLite and ISO8601 automatically
                return parser.parse(inputTimeStamp)
        except Exception:
            return None

    # Unrecognized type
    return None


# -------------------------------------------------------------------------------------------
def format_date_iso(date1: str) -> str:
    """Return ISO 8601 string for a date or None if empty"""
    if date1 is None:
        return None
    dt = datetime.datetime.fromisoformat(date1) if isinstance(date1, str) else date1
    return dt.isoformat()

# -------------------------------------------------------------------------------------------
def format_event_date(date_str: str, event_type: str) -> str:
    """Format event date with fallback rules."""
    if date_str:
        return format_date(date_str)
    elif event_type == "<missing event>":
        return "<missing event>"
    else:
        return "<still connected>"

# -------------------------------------------------------------------------------------------
def ensure_datetime(dt: Union[str, datetime.datetime, None]) -> datetime.datetime:
    if dt is None:
        return timeNowTZ()
    if isinstance(dt, str):
        return datetime.datetime.fromisoformat(dt)
    return dt


def parse_datetime(dt_str):
    if not dt_str:
        return None
    try:
        # Try ISO8601 first
        return datetime.datetime.fromisoformat(dt_str)
    except ValueError:
        # Try RFC1123 / HTTP format
        try:
            return datetime.datetime.strptime(dt_str, '%a, %d %b %Y %H:%M:%S GMT')
        except ValueError:
            return None

def format_date(date_str: str) -> str:
    try:
        dt = parse_datetime(date_str)
        if dt.tzinfo is None:
            # Set timezone if missing — change to timezone.utc if you prefer UTC
            now = datetime.datetime.now(conf.tz)
            dt = dt.replace(tzinfo=now.astimezone().tzinfo)
        return dt.astimezone().isoformat()
    except (ValueError, AttributeError, TypeError):
        return "invalid"

def format_date_diff(date1, date2, tz_name):
    """
    Return difference between two datetimes as 'Xd   HH:MM'.
    Uses app timezone if datetime is naive.
    date2 can be None (uses now).
    """
    # Get timezone from settings    
    tz = pytz.timezone(tz_name)

    def parse_dt(dt):
        if dt is None:
            return datetime.datetime.now(tz)
        if isinstance(dt, str):
            try:
                dt_parsed = email.utils.parsedate_to_datetime(dt)
            except (ValueError, TypeError):
             # fallback: parse ISO string
             dt_parsed = datetime.datetime.fromisoformat(dt)
            # convert naive GMT/UTC to app timezone
            if dt_parsed.tzinfo is None:
                dt_parsed = tz.localize(dt_parsed)
            else:
                dt_parsed = dt_parsed.astimezone(tz)
            return dt_parsed
        return dt if dt.tzinfo else tz.localize(dt)

    dt1 = parse_dt(date1)
    dt2 = parse_dt(date2)

    delta = dt2 - dt1
    total_minutes = int(delta.total_seconds() // 60)
    days, rem_minutes = divmod(total_minutes, 1440)  # 1440 mins in a day
    hours, minutes = divmod(rem_minutes, 60)

    return {
        "text": f"{days}d {hours:02}:{minutes:02}",
        "days": days,
        "hours": hours,
        "minutes": minutes,
        "total_minutes": total_minutes
    }