#!/data/data/com.termux/files/usr/bin/python3

import os
import sys
import termux_log_location as tll

LAST_YAML_SYMLINK_NAME = 'last.yml'


def symlink(src, dst, force=False):
    if force and os.path.lexists(dst):
        os.unlink(dst)
    os.symlink(src=src, dst=dst)


def load_last(target_dir_path):
    last_path = os.path.join(target_dir_path, LAST_YAML_SYMLINK_NAME)
    if os.path.exists(last_path):
        return tll.Position.load_yaml(
            path=os.path.realpath(last_path),
        )
    else:
        return None


def compute(target_dir_path, distance_threshold_metres):
    cur = tll.Position.from_termux_location()
    if cur:
        last = load_last(target_dir_path)
        if not last or tll.Position.haversine_distance_metres(last, cur) > distance_threshold_metres:
            cur_path = cur.save_yaml(target_dir_path)
            symlink(
                src=os.path.relpath(cur_path, start=target_dir_path),
                dst=os.path.join(target_dir_path, LAST_YAML_SYMLINK_NAME),
                force=True,
            )


def _init_argparser():
    import argparse
    argparser = argparse.ArgumentParser(description=None)
    argparser.add_argument(
        '--target-dir',
        metavar='PATH',
        dest='target_dir_path',
        default='.',
    )
    argparser.add_argument(
        '--distance-threshold',
        metavar='METRES',
        dest='distance_threshold_metres',
        default=0,
        type=float,
    )
    return argparser


def main(argv):
    argparser = _init_argparser()
    try:
        import argcomplete
        argcomplete.autocomplete(argparser)
    except ImportError:
        pass
    args = argparser.parse_args(argv)
    compute(**vars(args))
    return 0

if __name__ == "__main__":
    sys.exit(main(sys.argv[1:]))