"""# Git-based Time Tracker.

Quick and dirty time tracker on git histories.

Uses the simple heuristics that each commit takes precisely one hour of work.
It will automatically trim commits below one hour if another commit occurred
less than an hour ago.

Usage:

```
python -m git_time_tracker REPO1 REPO2...
```

# Obligatory

This tool reports:

```
project    Jmaa/git-time-tracker.git                    3h 33m  (2024)
```

And the ([Hamster](https://github.com/projecthamster/hamster)) manual time tracker reports:

![](docs/obligatory-hamster.png)
"""

import argparse
import datetime
import logging
import sys
from collections.abc import Iterator
from pathlib import Path

from .data import (
    HIDDEN_LABEL_PREFIX,
    HIDDEN_LABEL_TOTAL,
    RealizedWorkSample,
    WorkSample,
)
from .format import cli, icalendar
from .source import git_repo, csv_file

logger = logging.getLogger(__name__)


DEFAULT_ESTIMATED_DURATION = datetime.timedelta(hours=1)
ZERO_DURATION = datetime.timedelta(seconds=0)
HOUR = datetime.timedelta(hours=1)
MINUTE = datetime.timedelta(minutes=1)


def filter_samples(
    samples: list[WorkSample], sample_filter: set[str],
) -> list[WorkSample]:
    assert len(sample_filter) > 0
    return [s for s in samples if set(s.labels).intersection(sample_filter)]


def heuristically_realize_samples(
    samples: list[WorkSample],
) -> Iterator[RealizedWorkSample]:
    """Secret sauce.

    Guarentees that:
    * No samples overlap.
    """

    previous_sample_end = datetime.datetime.fromtimestamp(0, datetime.UTC)
    for sample in samples:
        end_at = sample.end_at

        assert previous_sample_end <= end_at, 'Iterating in incorrect order'

        # TODO: Allow end_at is None

        start_at = sample.start_at
        if start_at is None:
            estimated_duration: datetime.timedelta = DEFAULT_ESTIMATED_DURATION
            start_at = max(previous_sample_end, end_at - estimated_duration)
            del estimated_duration

        yield RealizedWorkSample(labels=sample.labels, end_at=end_at, start_at=start_at)

        previous_sample_end = sample.end_at
        del sample


def parse_arguments():
    parser = argparse.ArgumentParser()
    parser.add_argument(
        '--git-repo',
        action='extend',
        nargs='+',
        type=Path,
        dest='repositories',
        default=[],
    )
    parser.add_argument(
        '--csv-file',
        action='extend',
        nargs='+',
        type=Path,
        dest='csv_files',
        default=[],
    )
    parser.add_argument(
        '--filter',
        action='extend',
        nargs='+',
        type=str,
        dest='sample_filter',
        default=[],
    )
    parser.add_argument(
        '--format',
        action='store',
        type=str,
        dest='format_mode',
        default='cli_report',
        choices=['cli_report', 'icalendar'],
    )
    return parser.parse_args()

def load_samples(args):
    shared_time_stamps_set: set[WorkSample] = set()

    # Git repositories
    for repo_path in args.repositories:
        logger.warning('Determine commits from %s', repo_path)
        shared_time_stamps_set |= set(
            git_repo.iterate_samples_from_git_repository(repo_path),
        )
        del repo_path

    # CSV Files
    for csv_path in args.csv_files:
        logger.warning('Load samples from %s', csv_path)
        shared_time_stamps_set |= set(
            csv_file.iterate_samples_from_csv_file(csv_path),
        )
        del csv_path


    return shared_time_stamps_set

def main():
    logging.basicConfig()

    args = parse_arguments()

    # Determine samples
    shared_time_stamps_set = load_samples(args)

    # Sort samples
    shared_time_stamps = sorted(shared_time_stamps_set, key=lambda s: s.end_at)
    del shared_time_stamps_set

    # Filter samples
    sample_filter = args.sample_filter
    if len(sample_filter) != 0:
        logger.warning('Filtering %s samples', len(shared_time_stamps))
        shared_time_stamps = filter_samples(shared_time_stamps, sample_filter)
        logger.warning('Filtered down to %s samples', len(shared_time_stamps))

    # Heuristic samples
    logger.warning('Realizing %s samples', len(shared_time_stamps))
    shared_time_stamps = list(heuristically_realize_samples(shared_time_stamps))

    # Output format
    if args.format_mode == 'cli_report':
        for t in cli.generate_report(shared_time_stamps):
            sys.stdout.write(t)
    elif args.format_mode == 'icalendar':
        icalendar.generate_icalendar_file(
            shared_time_stamps, file='./output/samples.ics',
        )