# Copyright (c) Streamlit Inc. (2018-2022) Snowflake Inc. (2022-2024)
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#     http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.

from __future__ import annotations

import re
import textwrap
from typing import TYPE_CHECKING, Any, Final, cast

from streamlit.errors import StreamlitAPIException

if TYPE_CHECKING:
    from streamlit.type_util import SupportsStr

_ALPHANUMERIC_CHAR_REGEX: Final = re.compile(r"^[a-zA-Z0-9_&\-\. ]+$")


def decode_ascii(string: bytes) -> str:
    """Decodes a string as ascii."""
    return string.decode("ascii")


def clean_text(text: SupportsStr) -> str:
    """Convert an object to text, dedent it, and strip whitespace."""
    return textwrap.dedent(str(text)).strip()


def _contains_special_chars(text: str) -> bool:
    """Check if a string contains any special chars.

    Special chars in that case are all chars that are not
    alphanumeric, underscore, hyphen or whitespace.
    """
    return re.match(_ALPHANUMERIC_CHAR_REGEX, text) is None if text else False


def is_emoji(text: str) -> bool:
    """Check if input string is a valid emoji."""
    if not _contains_special_chars(text):
        return False

    from streamlit.emojis import ALL_EMOJIS

    return text.replace("\U0000fe0f", "") in ALL_EMOJIS


def is_material_icon(maybe_icon: str) -> bool:
    """Check if input string is a valid Material icon."""
    from streamlit.material_icon_names import ALL_MATERIAL_ICONS

    return maybe_icon in ALL_MATERIAL_ICONS


def validate_icon_or_emoji(icon: str | None) -> str:
    """Validate an icon or emoji and return it in normalized format if valid."""
    if icon is not None and icon.startswith(":material"):
        return validate_material_icon(icon)
    return validate_emoji(icon)


def validate_emoji(maybe_emoji: str | None) -> str:
    if maybe_emoji is None:
        return ""

    elif is_emoji(maybe_emoji):
        return maybe_emoji
    else:
        raise StreamlitAPIException(
            f'The value "{maybe_emoji}" is not a valid emoji. Shortcodes are not allowed, please use a single character instead.'
        )


def validate_material_icon(maybe_material_icon: str | None) -> str:
    """Validate a Material icon shortcode and return the icon in
    normalized format if valid."""

    supported_icon_packs = [
        "material",
    ]

    if maybe_material_icon is None:
        return ""

    icon_regex = r"^\s*:(.+)\/(.+):\s*$"
    icon_match = re.match(icon_regex, maybe_material_icon)
    # Since our markdown processing needs to change the `/` to `_` in order to
    # correctly render the icon, we need to add a zero-width space before the
    # `/` to avoid this transformation here.
    invisible_white_space = "\u200b"

    if not icon_match:
        raise StreamlitAPIException(
            f'The value `"{maybe_material_icon.replace("/", invisible_white_space + "/")}"` is not a valid Material icon. '
            f"Please use a Material icon shortcode like **`:material{invisible_white_space}/thumb_up:`**"
        )

    pack_name, icon_name = icon_match.groups()

    if (
        pack_name not in supported_icon_packs
        or not icon_name
        or not is_material_icon(icon_name)
    ):
        raise StreamlitAPIException(
            f'The value `"{maybe_material_icon.replace("/", invisible_white_space + "/")}"` is not a valid Material icon.'
            f" Please use a Material icon shortcode like **`:material{invisible_white_space}/thumb_up:`**. "
        )

    return f":{pack_name}/{icon_name}:"


def extract_leading_emoji(text: str) -> tuple[str, str]:
    """Return a tuple containing the first emoji found in the given string and
    the rest of the string (minus an optional separator between the two).
    """

    if not _contains_special_chars(text):
        # If the string only contains basic alphanumerical chars and/or
        # underscores, hyphen & whitespaces, then it's guaranteed that there
        # is no emoji in the string.
        return "", text

    from streamlit.emojis import EMOJI_EXTRACTION_REGEX

    re_match = re.search(EMOJI_EXTRACTION_REGEX, text)
    if re_match is None:
        return "", text

    # This cast to Any+type annotation weirdness is done because
    # cast(re.Match[str], ...) explodes at runtime since Python interprets it
    # as an attempt to index into re.Match instead of as a type annotation.
    re_match: re.Match[str] = cast(Any, re_match)
    return re_match.group(1), re_match.group(2)


def max_char_sequence(string: str, char: str) -> int:
    """Returns the count of the max sequence of a given char in a string."""
    max_sequence = 0
    current_sequence = 0
    for c in string:
        if c == char:
            current_sequence += 1
            max_sequence = max(max_sequence, current_sequence)
        else:
            current_sequence = 0

    return max_sequence


TEXTCHARS: Final = bytearray(
    {7, 8, 9, 10, 12, 13, 27} | set(range(0x20, 0x100)) - {0x7F}
)


def is_binary_string(inp: bytes) -> bool:
    """Guess if an input bytesarray can be encoded as a string."""
    # From https://stackoverflow.com/a/7392391
    return bool(inp.translate(None, TEXTCHARS))


def simplify_number(num: int) -> str:
    """Simplifies number into Human readable format, returns str"""
    num_converted = float(f"{num:.2g}")
    magnitude = 0
    while abs(num_converted) >= 1000:
        magnitude += 1
        num_converted /= 1000.0
    return "{}{}".format(
        f"{num_converted:f}".rstrip("0").rstrip("."),
        ["", "k", "m", "b", "t"][magnitude],
    )


_OBJ_MEM_ADDRESS: Final = re.compile(
    r"^\<[a-zA-Z_]+[a-zA-Z0-9<>._ ]* at 0x[0-9a-f]+\>$"
)


def is_mem_address_str(string):
    """Returns True if the string looks like <foo blarg at 0x15ee6f9a0>."""
    if _OBJ_MEM_ADDRESS.match(string):
        return True

    return False


_RE_CONTAINS_HTML: Final = re.compile(r"(?:</[^<]+>)|(?:<[^<]+/>)")


def probably_contains_html_tags(s: str) -> bool:
    """Returns True if the given string contains what seem to be HTML tags.

    Note that false positives/negatives are possible, so this function should not be
    used in contexts where complete correctness is required."""
    return bool(_RE_CONTAINS_HTML.search(s))
