import re
from pathlib import Path


def parse_tmva_matrix_to_array(
    input_class_files: list[str],
    simd_type: bool = False,
    outdir: str = "neural_net_training",
) -> list[str]:
    """Function to transform the TMVA output MLP C++ class into a more modern form.

    Args:
        input_class_file (str): Path to the .C MLP class created by TMVA.
        simd_type (bool, optional): If true, type in array is set to simd::float_v. Defaults to False.

    Returns:
        (str) : Path to the resulting C++ file containing the matrices.

    Note:
        The created C++ code is written to a `hpp` file in `neural_net_training/result`.

    """
    data_type = "float" if not simd_type else "simd::float_v"
    # TODO: as of writing this code, constexpr is not supported for the SIMD types
    constness = "constexpr" if not simd_type else "const"
    outfiles = []
    for input_class_file in input_class_files:
        print(f"Transforming {input_class_file} ...")
        input_class_file = Path(input_class_file)
        with open(input_class_file) as f:
            lines = f.readlines()
        # the name of the outputfile is the middle part of the input class file name
        outfile = (
            outdir
            + "/result/"
            + "_".join(str(input_class_file.stem).split("_")[1:-1])
            + ".hpp"
        )
        # this only supports category 2 for the transformation, which is the largest/smallest for fMax_1/fMin_1
        min_lines = [
            line.replace(";", "").split("=")[-1].strip()
            for line in lines
            if "fMin_1[2]" in line and "Scal" not in line and "double" not in line
        ]
        max_lines = [
            line.replace(";", "").split("=")[-1].strip()
            for line in lines
            if "fMax_1[2]" in line and "Scal" not in line and "double" not in line
        ]
        minima_cpp_decl = (
            f"{constness} auto fMin = std::array<{data_type}, {len(min_lines)}>"
            + "{{"
            + ", ".join(min_lines)
            + "}};\n"
        )
        maxima_cpp_decl = (
            f"{constness} auto fMax = std::array<{data_type}, {len(max_lines)}>"
            + "{{"
            + ", ".join(max_lines)
            + "}};\n"
        )
        print(f"Found minimum and maximum values for {len(min_lines)} variables.")
        with open(outfile, "w") as out:
            out.writelines([minima_cpp_decl, maxima_cpp_decl])

        # this list contains all lines that define a matrix element
        matrix_lines = [
            line.replace(";", "").strip()
            for line in lines
            if "fWeightMatrix" in line
            and "double" not in line
            and "*" not in line
            and "= fWeightMatrix" not in line
        ]

        # there are several matrices, figure out how many and loop accordingly
        n_matrices = int(re.findall(re.compile(r"(\d+)\["), matrix_lines[-1])[0])
        print(f"Found {n_matrices} matrices: ")
        for matrix in range(n_matrices):
            # get only entries for corresponding matrix
            matrix_entries = [m for m in matrix_lines if f"{matrix}to{(matrix+1)}" in m]
            # figure out the dimensions of the matrix, by checking largest index at the end
            dim_string = re.findall(re.compile(r"\[(\d+)\]"), matrix_entries[-1])
            # actual size is last index + 1
            n_rows = int(dim_string[0]) + 1
            n_cols = int(dim_string[1]) + 1
            # get the name of the matrix
            matrix_string = matrix_entries[matrix * n_rows].split("=")[0].split("[")[0]
            if n_rows > 1:
                cpp_decl = (
                    f"{constness} auto {matrix_string} = std::array<std::array<{data_type}, {n_cols}>, {n_rows}>"
                    + "{{"
                )
            else:
                cpp_decl = (
                    f"{constness} auto {matrix_string} = std::array<{data_type}, {n_cols}>"
                    + "{"
                )
            rows = [[] for _ in range(n_rows)]
            for i_col in range(n_cols):
                for i_row, row in enumerate(rows):
                    # only keep number (right side of the equality sign)
                    entry = (
                        matrix_entries[i_col * n_rows + i_row].split("=")[-1].strip()
                    )
                    row.append(entry)
            array_strings = ["{" + ", ".join(row) + "}" for row in rows]
            cpp_decl += ", ".join(array_strings) + ("}};\n" if n_rows > 1 else "};\n")
            print(
                f"    {matrix+1}. {matrix_string} with {n_cols} columns and {n_rows} rows",
            )
            with open(outfile, "a") as out:
                out.write(cpp_decl)
            outfiles.append(outfile)
    return outfiles


if __name__ == "__main__":
    outfiles = parse_tmva_matrix_to_array(
        [
            "neural_net_training/result/GhostNNDataSet/weights/TMVAClassification_default_forward_ghost_mlp.class.C",
            "neural_net_training/result/GhostNNDataSet/weights/TMVAClassification_veloUT_forward_ghost_mlp.class.C",
        ],
    )

    try:
        import subprocess

        # run clang-format for nicer looking result
        for outfile in outfiles:
            subprocess.run(
                [
                    "clang-format",
                    "-i",
                    f"{outfile}",
                ],
                check=True,
            )
    except:
        pass