"""
LaTeX Builder for fluent construction of LaTeX expressions.

This builder provides a fluent interface for constructing complex LaTeX
expressions with proper brace balancing and formatting.
"""

from typing import List, Optional


class LaTeXBuilder:
    """
    Fluent builder for constructing LaTeX expressions.

    This builder provides method chaining for building complex LaTeX
    expressions with automatic brace balancing and spacing optimization.

    Examples:
        Simple fraction:
            >>> builder = LaTeXBuilder()
            >>> result = builder.add_fraction("a", "b").build()
            >>> result
            '\\frac{a}{b}'

        Superscript:
            >>> builder = LaTeXBuilder()
            >>> result = builder.add_superscript("x", "2").build()
            >>> result
            'x^{2}'

        Complex expression:
            >>> builder = LaTeXBuilder()
            >>> result = (builder
            ...     .add_command("sin", "x")
            ...     .add_text(" + ")
            ...     .add_fraction("1", "2")
            ...     .build())
            >>> result
            '\\sin{x} + \\frac{1}{2}'

        Nested fractions:
            >>> builder = LaTeXBuilder()
            >>> inner = LaTeXBuilder().add_fraction("a", "b").build()
            >>> result = builder.add_fraction(inner, "c").build()
            >>> result
            '\\frac{\\frac{a}{b}}{c}'
    """

    def __init__(self):
        """Initialize the LaTeX builder."""
        self._parts: List[str] = []

    def add_text(self, text: str) -> 'LaTeXBuilder':
        """
        Add raw text to the LaTeX expression.

        Args:
            text: The text to add (no processing)

        Returns:
            Self for method chaining

        Examples:
            >>> builder = LaTeXBuilder()
            >>> builder.add_text("x + y").build()
            'x + y'
        """
        if text:
            self._parts.append(text)
        return self

    def add_command(self, cmd: str, arg: str) -> 'LaTeXBuilder':
        """
        Add a LaTeX command with one argument: \\cmd{arg}

        Args:
            cmd: The command name (without backslash)
            arg: The argument content

        Returns:
            Self for method chaining

        Examples:
            >>> builder = LaTeXBuilder()
            >>> builder.add_command("sin", "x").build()
            '\\sin{x}'

            >>> builder = LaTeXBuilder()
            >>> builder.add_command("text", "hello").build()
            '\\text{hello}'
        """
        self._parts.append(f"\\{cmd}{{{arg}}}")
        return self

    def add_fraction(self, numerator: str, denominator: str) -> 'LaTeXBuilder':
        """
        Add a fraction: \\frac{numerator}{denominator}

        Args:
            numerator: The numerator expression
            denominator: The denominator expression

        Returns:
            Self for method chaining

        Examples:
            >>> builder = LaTeXBuilder()
            >>> builder.add_fraction("a", "b").build()
            '\\frac{a}{b}'

            >>> builder = LaTeXBuilder()
            >>> builder.add_fraction("x + 1", "y - 2").build()
            '\\frac{x + 1}{y - 2}'
        """
        self._parts.append(f"\\frac{{{numerator}}}{{{denominator}}}")
        return self

    def add_superscript(self, base: str, superscript: str) -> 'LaTeXBuilder':
        """
        Add a superscript: base^{superscript}

        Args:
            base: The base expression
            superscript: The superscript expression

        Returns:
            Self for method chaining

        Examples:
            >>> builder = LaTeXBuilder()
            >>> builder.add_superscript("x", "2").build()
            'x^{2}'

            >>> builder = LaTeXBuilder()
            >>> builder.add_superscript("e", "i\\pi").build()
            'e^{i\\pi}'
        """
        self._parts.append(f"{base}^{{{superscript}}}")
        return self

    def add_subscript(self, base: str, subscript: str) -> 'LaTeXBuilder':
        """
        Add a subscript: base_{subscript}

        Args:
            base: The base expression
            subscript: The subscript expression

        Returns:
            Self for method chaining

        Examples:
            >>> builder = LaTeXBuilder()
            >>> builder.add_subscript("x", "1").build()
            'x_{1}'

            >>> builder = LaTeXBuilder()
            >>> builder.add_subscript("a", "i+j").build()
            'a_{i+j}'
        """
        self._parts.append(f"{base}_{{{subscript}}}")
        return self

    def add_subscript_superscript(self, base: str, subscript: str, superscript: str) -> 'LaTeXBuilder':
        """
        Add both subscript and superscript: base_{subscript}^{superscript}

        Args:
            base: The base expression
            subscript: The subscript expression
            superscript: The superscript expression

        Returns:
            Self for method chaining

        Examples:
            >>> builder = LaTeXBuilder()
            >>> builder.add_subscript_superscript("x", "1", "2").build()
            'x_{1}^{2}'

            >>> builder = LaTeXBuilder()
            >>> builder.add_subscript_superscript("R", "i", "j").build()
            'R_{i}^{j}'
        """
        self._parts.append(f"{base}_{{{subscript}}}^{{{superscript}}}")
        return self

    def add_sqrt(self, content: str, root: Optional[str] = None) -> 'LaTeXBuilder':
        """
        Add a square root or nth root.

        Args:
            content: The content under the root
            root: Optional root index (None for square root)

        Returns:
            Self for method chaining

        Examples:
            >>> builder = LaTeXBuilder()
            >>> builder.add_sqrt("x").build()
            '\\sqrt{x}'

            >>> builder = LaTeXBuilder()
            >>> builder.add_sqrt("x", "3").build()
            '\\sqrt[3]{x}'
        """
        if root:
            self._parts.append(f"\\sqrt[{root}]{{{content}}}")
        else:
            self._parts.append(f"\\sqrt{{{content}}}")
        return self

    def add_environment(self, env: str, content: str) -> 'LaTeXBuilder':
        """
        Add a LaTeX environment: \\begin{env}content\\end{env}

        Args:
            env: The environment name
            content: The environment content

        Returns:
            Self for method chaining

        Examples:
            >>> builder = LaTeXBuilder()
            >>> builder.add_environment("cases", "x & x > 0 \\\\\\\\ 0 & x \\\\leq 0").build()
            '\\begin{cases}x & x > 0 \\\\\\\\ 0 & x \\\\leq 0\\end{cases}'
        """
        self._parts.append(f"\\begin{{{env}}}{content}\\end{{{env}}}")
        return self

    def add_delimiter_pair(self, left: str, content: str, right: str) -> 'LaTeXBuilder':
        """
        Add delimiter pair: \\left{left}content\\right{right}

        Args:
            left: The left delimiter
            content: The content between delimiters
            right: The right delimiter

        Returns:
            Self for method chaining

        Examples:
            >>> builder = LaTeXBuilder()
            >>> builder.add_delimiter_pair("(", "x + y", ")").build()
            '\\left(x + y\\right)'

            >>> builder = LaTeXBuilder()
            >>> builder.add_delimiter_pair("\\\\{", "a, b, c", "\\\\}").build()
            '\\left\\\\{a, b, c\\right\\\\}'
        """
        self._parts.append(f"\\left{left}{content}\\right{right}")
        return self

    def add_matrix(self, rows: List[List[str]], environment: str = "matrix") -> 'LaTeXBuilder':
        """
        Add a matrix environment.

        Args:
            rows: List of rows, each row is a list of cell contents
            environment: The matrix environment (matrix, pmatrix, bmatrix, etc.)

        Returns:
            Self for method chaining

        Examples:
            >>> builder = LaTeXBuilder()
            >>> rows = [["a", "b"], ["c", "d"]]
            >>> builder.add_matrix(rows, "pmatrix").build()
            '\\begin{pmatrix}a & b \\\\\\\\ c & d\\end{pmatrix}'
        """
        matrix_content = " \\\\ ".join(
            " & ".join(cell for cell in row)
            for row in rows
        )
        self._parts.append(f"\\begin{{{environment}}}{matrix_content}\\end{{{environment}}}")
        return self

    def clear(self) -> 'LaTeXBuilder':
        """
        Clear all parts (reset the builder).

        Returns:
            Self for method chaining

        Examples:
            >>> builder = LaTeXBuilder()
            >>> builder.add_text("x").clear().add_text("y").build()
            'y'
        """
        self._parts.clear()
        return self

    def build(self) -> str:
        """
        Build the final LaTeX string.

        Returns:
            The constructed LaTeX expression

        Examples:
            >>> builder = LaTeXBuilder()
            >>> builder.add_fraction("a", "b").build()
            '\\frac{a}{b}'

            >>> builder = LaTeXBuilder()
            >>> builder.add_text("x").add_text(" + ").add_text("y").build()
            'x + y'
        """
        return "".join(self._parts)

    def __str__(self) -> str:
        """String representation (same as build())."""
        return self.build()

    def __repr__(self) -> str:
        """Debug representation."""
        return f"LaTeXBuilder(parts={len(self._parts)})"