# utils.py
#
# Copyright 2021 James Westman <james@jwestman.net>
#
# This file is free software; you can redistribute it and/or modify it
# under the terms of the GNU Lesser General Public License as
# published by the Free Software Foundation; either version 3 of the
# License, or (at your option) any later version.
#
# This file is distributed in the hope that it will be useful, but
# WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
# Lesser General Public License for more details.
#
# You should have received a copy of the GNU Lesser General Public
# License along with this program.  If not, see <http://www.gnu.org/licenses/>.
#
# SPDX-License-Identifier: LGPL-3.0-or-later

import itertools
import typing as T
from dataclasses import dataclass


class Colors:
    RED = "\033[91m"
    GREEN = "\033[92m"
    YELLOW = "\033[33m"
    PURPLE = "\033[35m"
    FAINT = "\033[2m"
    BOLD = "\033[1m"
    BLUE = "\033[34m"
    UNDERLINE = "\033[4m"
    NO_UNDERLINE = "\033[24m"
    CLEAR = "\033[0m"


def did_you_mean(word: str, options: T.List[str]) -> T.Optional[str]:
    if len(options) == 0:
        return None

    def levenshtein(a, b):
        # see https://en.wikipedia.org/wiki/Levenshtein_distance
        m = len(a)
        n = len(b)

        distances = [[0 for j in range(n)] for i in range(m)]

        for i in range(m):
            distances[i][0] = i
        for j in range(n):
            distances[0][j] = j

        for j in range(1, n):
            for i in range(1, m):
                cost = 0
                if a[i] != b[j]:
                    if a[i].casefold() == b[j].casefold():
                        cost = 1
                    else:
                        cost = 2
                distances[i][j] = min(
                    distances[i - 1][j] + 2,
                    distances[i][j - 1] + 2,
                    distances[i - 1][j - 1] + cost,
                )

        return distances[m - 1][n - 1]

    distances = [(option, levenshtein(word, option)) for option in options]
    closest = min(distances, key=lambda item: item[1])
    if closest[1] <= 5:
        return closest[0]
    return None


def idx_to_pos(idx: int, text: str) -> T.Tuple[int, int]:
    if idx == 0 or len(text) == 0:
        return (0, 0)
    line_num = text.count("\n", 0, idx) + 1
    col_num = idx - text.rfind("\n", 0, idx) - 1
    return (line_num - 1, col_num)


def pos_to_idx(line: int, col: int, text: str) -> int:
    lines = text.splitlines(keepends=True)
    return sum([len(line) for line in lines[:line]]) + col


def idxs_to_range(start: int, end: int, text: str):
    start_l, start_c = idx_to_pos(start, text)
    end_l, end_c = idx_to_pos(end, text)
    return {
        "start": {
            "line": start_l,
            "character": start_c,
        },
        "end": {
            "line": end_l,
            "character": end_c,
        },
    }


@dataclass
class UnescapeError(Exception):
    start: int
    end: int


def escape_quote(string: str) -> str:
    return (
        '"'
        + (
            string.replace("\\", "\\\\")
            .replace('"', '\\"')
            .replace("\n", "\\n")
            .replace("\t", "\\t")
        )
        + '"'
    )


def unescape_quote(string: str) -> str:
    string = string[1:-1]

    REPLACEMENTS = {
        "\n": "\n",
        "\\": "\\",
        "n": "\n",
        "t": "\t",
        '"': '"',
        "'": "'",
    }

    result = ""
    i = 0
    while i < len(string):
        c = string[i]
        if c == "\\":
            i += 1

            if i >= len(string):
                from .errors import CompilerBugError

                raise CompilerBugError()

            if r := REPLACEMENTS.get(string[i]):
                result += r
            else:
                raise UnescapeError(i, i + 2)
        else:
            result += c

        i += 1

    return result


def iter_batched(iterable, n, *, strict=False):
    """
    Replacement for `itertools.batched()` since the testing infrastructure
    uses Python 3.9 at the moment. Copied directly off of the Python docs.
    """
    # batched('ABCDEFG', 3) → ABC DEF G
    if n < 1:
        raise ValueError("n must be at least one")
    iterator = iter(iterable)
    while batch := tuple(itertools.islice(iterator, n)):
        if strict and len(batch) != n:
            raise ValueError("batched(): incomplete batch")
        yield batch