import time
from datetime import datetime, timedelta
import numpy as np
import matplotlib.pyplot as pl


def get_current_time():
    """Returns the current time in seconds since the epoch."""
    return time.time()


def generate_timestrings(start_time_str, end_time_str, dt):
    """Generates a list of timestamps from start_time to end_time, which are strings such
    as 19:00."""

    timestamps = []
    current_time = datetime.strptime(start_time_str, "%H:%M")
    end_time = datetime.strptime(end_time_str, "%H:%M")
    while current_time <= end_time:
        timestamps.append(current_time)
        current_time += timedelta(seconds=dt)
    timestrings = [dt.strftime("%H:%M") for dt in timestamps]
    return timestrings


def index_peak_times(timestamps, peak_times, peak_durations):
    """Converts peak times from HH:MM format to seconds since epoch."""
    # start_time is the start time of the batch process in seconds since the epoch
    # peak_times is a list of strings in HH:MM format
    dt = timestamps[1] - timestamps[0]  # time step in seconds
    peak_indices = np.zeros(len(timestamps), dtype=int)
    start_datetime = datetime.fromtimestamp(timestamps[0])
    processed_times = []
    peak_occurence_no = 1
    for time_str, duration in zip(peak_times, peak_durations):
        # convert HH:MM to a datetime object
        time_obj = datetime.strptime(time_str, "%H:%M")
        full_datetime = start_datetime.replace(
            hour=time_obj.hour, minute=time_obj.minute, second=0, microsecond=0
        )
        peak_start = int(full_datetime.timestamp())
        peak_end = peak_start + duration * 60  # duration in minutes to seconds
        peak_timestamps = np.arange(peak_start, peak_end, dt, dtype=int)

        common, indices_ts, _ = np.intersect1d(
            timestamps, peak_timestamps, return_indices=True
        )
        peak_indices[indices_ts] = peak_occurence_no
        peak_occurence_no += 1

    pl.plot(peak_indices, label="Peak Indices")
    pl.show()

    return processed_times