r"""
Visitor for <msqrt> (square root) MathML elements.

The <msqrt> element represents square roots (√).
The LaTeX conversion uses \sqrt{...} notation.
"""

from lxml import etree as ET
from ..core.interfaces import Visitor, Strategy
from ..utils import text_content as _text_content, local_name as _local


class MsqrtVisitor(Visitor):
    r"""
    Handles <msqrt> (square root) MathML elements.

    Converts square root expressions to LaTeX \sqrt notation.

    Examples:
        Simple number:
            <msqrt><mn>2</mn></msqrt> → \sqrt{2}

        Variable:
            <msqrt><mi>x</mi></msqrt> → \sqrt{x}

        Complex expression:
            <msqrt>
              <mrow><mi>x</mi><mo>+</mo><mn>1</mn></mrow>
            </msqrt>
            → \sqrt{x + 1}

        Nested root:
            <msqrt><msqrt><mi>x</mi></msqrt></msqrt> → \sqrt{\sqrt{x}}

        Fraction under root:
            <msqrt><mfrac><mn>1</mn><mn>2</mn></mfrac></msqrt> → \sqrt{\dfrac{1}{2}}
    """

    def __init__(self, strategy: Strategy):
        """Initialize the Msqrt visitor."""
        super().__init__(strategy)

    def visit(self, node: ET.Element) -> str:
        r"""
        Convert <msqrt> element to LaTeX.

        Args:
            node: The <msqrt> element to convert

        Returns:
            LaTeX square root string (\sqrt{content})

        Raises:
            ValueError: If node is not an <msqrt> element
        """
        if not self.can_handle(node):
            raise ValueError(f"MsqrtVisitor cannot handle element '{node.tag}'")

        children = list(node)

        # Empty msqrt (edge case)
        if not children:
            return "\\sqrt{}"

        # Convert all children and join with spaces
        parts = []
        for child in children:
            part = self._convert_child(child)
            if part:  # Only add non-empty parts
                parts.append(part)

        radicand = ' '.join(parts).strip()

        # Return \sqrt{radicand}
        return f"\\sqrt{self._brace(radicand)}"

    def _convert_child(self, child: ET.Element) -> str:
        """
        Convert a child element to LaTeX.

        This method instantiates the appropriate visitor for each child type.
        """
        tag = _local(child.tag)

        # Import visitors as needed to avoid circular imports
        if tag == 'mi':
            from .mi_visitor import MiVisitor
            return MiVisitor(self.strategy).visit(child)
        elif tag == 'mo':
            from .mo_visitor import MoVisitor
            return MoVisitor(self.strategy).visit(child)
        elif tag == 'mn':
            from .mn_visitor import MnVisitor
            return MnVisitor(self.strategy).visit(child)
        elif tag == 'mfrac':
            from .mfrac_visitor import MfracVisitor
            return MfracVisitor(self.strategy).visit(child)
        elif tag == 'msup':
            from .msup_visitor import MsupVisitor
            return MsupVisitor(self.strategy).visit(child)
        elif tag == 'msub':
            from .msub_visitor import MsubVisitor
            return MsubVisitor(self.strategy).visit(child)
        elif tag == 'mrow':
            from .mrow_visitor import MrowVisitor
            return MrowVisitor(self.strategy).visit(child)
        elif tag == 'msqrt':
            # Recursive: msqrt can contain other msqrt elements
            return self.visit(child)
        elif tag == 'mroot':
            from .mroot_visitor import MrootVisitor
            return MrootVisitor(self.strategy).visit(child)
        elif tag == 'msubsup':
            from .msubsup_visitor import MsubsupVisitor
            return MsubsupVisitor(self.strategy).visit(child)
        elif tag == 'munder':
            from .munder_visitor import MunderVisitor
            return MunderVisitor(self.strategy).visit(child)
        elif tag == 'mover':
            from .mover_visitor import MoverVisitor
            return MoverVisitor(self.strategy).visit(child)
        elif tag == 'munderover':
            from .munderover_visitor import MunderoverVisitor
            return MunderoverVisitor(self.strategy).visit(child)
        elif tag == 'mfenced':
            from .mfenced_visitor import MfencedVisitor
            return MfencedVisitor(self.strategy).visit(child)
        elif tag == 'mtable':
            from .mtable_visitor import MtableVisitor
            return MtableVisitor(self.strategy).visit(child)
        elif tag == 'mtext':
            from .mtext_visitor import MtextVisitor
            return MtextVisitor(self.strategy).visit(child)
        elif tag == 'mstyle':
            from .mstyle_visitor import MstyleVisitor
            return MstyleVisitor(self.strategy).visit(child)
        elif tag == 'mspace':
            from .mspace_visitor import MspaceVisitor
            return MspaceVisitor(self.strategy).visit(child)
        elif tag == 'menclose':
            from .menclose_visitor import MencloseVisitor
            return MencloseVisitor(self.strategy).visit(child)
        elif tag == 'mmultiscripts':
            from .mmultiscripts_visitor import MmultiscriptsVisitor
            return MmultiscriptsVisitor(self.strategy).visit(child)
        elif tag == 'maction':
            from .maction_visitor import MactionVisitor
            return MactionVisitor(self.strategy).visit(child)
        elif tag == 'merror':
            from .merror_visitor import MerrorVisitor
            return MerrorVisitor(self.strategy).visit(child)
        elif tag == 'mpadded':
            from .mpadded_visitor import MpaddedVisitor
            return MpaddedVisitor(self.strategy).visit(child)
        elif tag == 'mphantom':
            from .mphantom_visitor import MphantomVisitor
            return MphantomVisitor(self.strategy).visit(child)
        elif tag == 'ms':
            from .ms_visitor import MsVisitor
            return MsVisitor(self.strategy).visit(child)
        elif tag == 'mglyph':
            from .mglyph_visitor import MglyphVisitor
            return MglyphVisitor(self.strategy).visit(child)
        elif tag == 'maligngroup':
            from .maligngroup_visitor import MaligngroupVisitor
            return MaligngroupVisitor(self.strategy).visit(child)
        elif tag == 'malignmark':
            from .malignmark_visitor import MalignmarkVisitor
            return MalignmarkVisitor(self.strategy).visit(child)
        elif tag == 'mlabeledtr':
            from .mlabeledtr_visitor import MlabeledtrVisitor
            return MlabeledtrVisitor(self.strategy).visit(child)
        else:
            # Fallback: return text content for unknown elements
            import sys
            print(f"[WARNING] Unknown element <{tag}> in msqrt, using text fallback", file=sys.stderr)
            return _text_content(child)

    def _brace(self, content: str) -> str:
        """Wrap content in braces."""
        return f"{{{content}}}"

    def can_handle(self, node: ET.Element) -> bool:
        """Check if this visitor can handle the given node."""
        return _local(node.tag) == 'msqrt'

    @property
    def element_name(self) -> str:
        """Get the element name this visitor handles."""
        return 'msqrt'

    def __repr__(self) -> str:
        """String representation for debugging."""
        return f"MsqrtVisitor(strategy={self.strategy.name})"