# Copyright (c) Microsoft. All rights reserved.

import logging
from typing import TYPE_CHECKING, ClassVar, Optional

from pydantic import field_validator

from semantic_kernel.template_engine.blocks.block import Block
from semantic_kernel.template_engine.blocks.block_types import BlockTypes

if TYPE_CHECKING:
    from semantic_kernel.functions.kernel_arguments import KernelArguments
    from semantic_kernel.kernel import Kernel

logger: logging.Logger = logging.getLogger(__name__)


class TextBlock(Block):
    """A block with text content."""

    type: ClassVar[BlockTypes] = BlockTypes.TEXT

    @field_validator("content", mode="before")
    @classmethod
    def content_strip(cls, content: str):
        """Strip the content of the text block.

        Overload strip method, text blocks are not stripped.
        """
        return content

    @classmethod
    def from_text(
        cls,
        text: str | None = None,
        start_index: int | None = None,
        stop_index: int | None = None,
    ):
        """Create a text block from a string."""
        if text is None:
            return cls(content="")
        if start_index is not None and stop_index is not None:
            if start_index > stop_index:
                raise ValueError(f"start_index ({start_index}) must be less than stop_index ({stop_index})")

            if start_index < 0:
                raise ValueError(f"start_index ({start_index}) must be greater than 0")

            text = text[start_index:stop_index]
        elif start_index is not None:
            text = text[start_index:]
        elif stop_index is not None:
            text = text[:stop_index]

        return cls(content=text)

    def render(self, *_: tuple[Optional["Kernel"], Optional["KernelArguments"]]) -> str:
        """Render the text block."""
        return self.content