ickc/pantable

from __future__ import annotations

import csv
import io
from logging import getLogger
from pathlib import Path
from typing import TYPE_CHECKING

import numpy as np

from .util import EmptyTableError

if TYPE_CHECKING:
    from typing import List

    from .ast import PanTableOption

logger = getLogger('pantable')


def load_csv(
    data: str,
    options: PanTableOption,
) -> List[List[str]]:
    '''loading CSV table

    Note that this can emit EmptyTableError, FileNotFoundError
    '''
    include = options.include
    # TODO: PY37
    # encoding = encoding_ if (encoding_ := options.include_encoding) else None
    encoding = options.include_encoding
    # default include_encoding is ''
    # default encoding below is None
    if not encoding:
        encoding = None
    try:
        with (
            open(include, encoding=encoding, newline='')
        ) if include else (
            io.StringIO(data, newline='')
        ) as f:
            table_list = list(csv.reader(f, **options.csv_kwargs))
        if table_list:
            for row in table_list:
                if row:
                    for i in row:
                        if i.strip():
                            return table_list
        raise EmptyTableError
    except FileNotFoundError:
        raise FileNotFoundError(f'include path {include} not found.')


def load_csv_array(
    data: str,
    options: PanTableOption,
) -> np.ndarray[np.str_]:
    '''loading CSV table in `numpy.ndarray`

    Note that this can emit EmptyTableError, FileNotFoundError
    '''
    table_list = load_csv(data, options)
    m = len(table_list)
    n = max(len(row) for row in table_list)
    res = np.full((m, n), '', dtype=np.object_)
    for i, row in enumerate(table_list):
        for j, cell in enumerate(row):
            res[i, j] = cell
    return res


def dump_csv(
    data: np.ndarray[np.str_],
    options: PanTableOption,
) -> str:
    '''dump data as CSV string
    '''
    with io.StringIO(newline='') as f:
        writer = csv.writer(f, **options.csv_kwargs)
        writer.writerows(data)
        return f.getvalue()


def dump_csv_io(
    data: np.ndarray[np.str_],
    options: PanTableOption,
) -> str:
    '''dump data as CSV

    it will mutate options.include if it is an invalid write path.
    '''
    _include = options.include

    text = dump_csv(data, options)

    if _include:
        try:
            include = Path(_include)
            include.parent.mkdir(parents=True, exist_ok=True)
            with open(include, 'x', encoding=options.include_encoding, newline='') as f:
                f.write(text)
            return ''
        except (PermissionError, FileExistsError):
            logger.error(f'Data cannot be written to file {options.include}, Overriding include path to empty...')
            options.include = ''
    return text