# Parses niph's lunations calculator at https://github.com/dlebansais/PgMoon/blob/master/PgMoon-Plugin/PhaseCalculator.Lunations.cs
# this is itself from PG code shared by Citan and should be 100% accurate
# the output is a TSV of dates (starting at the relatively arbitrary 4/11/2021)

# requires python 3.9+. On Windows machines, it also depends on an up-to-date tzdata package
# (python -m pip install tzdata)

import datetime
import re
from zoneinfo import ZoneInfo
from typing import IO


LINEMATCH_RE = re.compile(
    r'new\(\) \{ Index = (?P<index>\d+), NewMoon = ParseDateTime\("(?P<new_moon>\d\d/\d\d/\d\d\d\d \d\d:\d\d:\d\d)"\), WaxingCrescentMoon = ParseDateTime\("(?P<waxing_crescent_moon>\d\d/\d\d/\d\d\d\d \d\d:\d\d:\d\d)"\), QuarterMoon = ParseDateTime\("(?P<quarter_moon>\d\d/\d\d/\d\d\d\d \d\d:\d\d:\d\d)"\), WaxingGibbousMoon = ParseDateTime\("(?P<waxing_gibbous_moon>\d\d/\d\d/\d\d\d\d \d\d:\d\d:\d\d)"\), FullMoon = ParseDateTime\("(?P<full_moon>\d\d/\d\d/\d\d\d\d \d\d:\d\d:\d\d)"\), WaningGibbousMoon = ParseDateTime\("(?P<waning_gibbous_moon>\d\d/\d\d/\d\d\d\d \d\d:\d\d:\d\d)"\), LastQuarterMoon = ParseDateTime\("(?P<last_quarter_moon>\d\d/\d\d/\d\d\d\d \d\d:\d\d:\d\d)"\), WaningCrescentMoon = ParseDateTime\("(?P<waning_crescent_moon>\d\d/\d\d/\d\d\d\d \d\d:\d\d:\d\d)"\), Duration = ParseTimeSpan\("(?P<duration>\d+\.\d+):00:00"\) },'
)
IGNORE = {
    "namespace PgMoon;",
    "",
    "/// <summary>",
    "/// Represents a moon phase calculator.",
    "/// </summary>",
    "public partial class PhaseCalculator",
    "{",
    "private static readonly Lunation[] LunationTable =",
    "[",
    "];",
    "}",
}
SKIP_TO_THIS_DATE = datetime.datetime(2021, 4, 11, tzinfo=datetime.UTC)

lunation_to_sheet = (
    ("new_moon", "New"),
    ("waxing_crescent_moon", "Waxing Crescent"),
    ("quarter_moon", "First Quarter"),
    ("waxing_gibbous_moon", "Waxing Gibbous"),
    ("full_moon", "Full"),
    ("waning_gibbous_moon", "Waning Gibbous"),
    ("last_quarter_moon", "Third Quarter"),
    ("waning_crescent_moon", "Waning Crescent"),
)


def main(f: IO, tformat: str):
    last_phase_dt, last_phase_sheet_name = None, None
    for line in f.readlines():
        stripped = line.strip()
        if stripped in IGNORE:
            continue
        if lunation := LINEMATCH_RE.match(stripped):
            idx = int(lunation["index"])
            # duration = datetime.timedelta(days=float(lunation["duration"]))
            #  ^ also available if needed, the total duration of the lunation
            for phase_idx, phase_sheet_name in lunation_to_sheet:
                phase_start_dt = (
                    datetime.datetime.strptime(lunation[phase_idx], "%m/%d/%Y %H:%M:%S")
                    .replace(tzinfo=datetime.UTC)
                    .astimezone(tz=ZoneInfo("US/Eastern"))
                )

                if phase_start_dt < SKIP_TO_THIS_DATE:
                    continue
                if phase_start_dt.hour != 0:
                    raise Exception(
                        f"{idx=} had phase not at midnight Eastern {phase_idx=},{phase_start_dt=}"
                    )
                if last_phase_dt:
                    for i in range((phase_start_dt - last_phase_dt).days):
                        print(
                            f"{(last_phase_dt + datetime.timedelta(days=i)).strftime('%#m/%#d/%Y')}\t{last_phase_sheet_name}"
                        )
                last_phase_dt = phase_start_dt
                last_phase_sheet_name = phase_sheet_name
        else:
            raise Exception(f"didn't match:\n{stripped}, add to ignore or adjust regex")

    assert last_phase_dt
    print(f"{last_phase_dt.strftime(tformat)}\t{last_phase_sheet_name}")


if __name__ == "__main__":
    import platform

    if platform.system() == "Windows":
        format = "%#m/%#d/%Y"
    else:
        format = "%-m/%-d/%Y"

    with open("PhaseCalculator.Lunations.cs") as f:
        main(f, format)