"""Utilities for Qchem io."""

from __future__ import annotations

import re
from collections import defaultdict

import numpy as np

__author__ = "Samuel Blau, Brandon Wood, Shyam Dwaraknath, Evan Spotte-Smith, Ryan Kingsbury"
__copyright__ = "Copyright 2018-2022, The Materials Project"


def read_pattern(text_str, patterns, terminate_on_match=False, postprocess=str):
    r"""General pattern reading on an input string.

    Args:
        text_str (str): the input string to search for patterns
        patterns (dict): A dict of patterns, e.g.
            {"energy": r"energy\\(sigma->0\\)\\s+=\\s+([\\d\\-.]+)"}.
        terminate_on_match (bool): Whether to terminate when there is at
            least one match in each key in pattern.
        postprocess (callable): A post processing function to convert all
            matches. Defaults to str, i.e., no change.

    Renders accessible:
        Any attribute in patterns. For example,
        {"energy": r"energy\\(sigma->0\\)\\s+=\\s+([\\d\\-.]+)"} will set the
        value of matches["energy"] = [[-1234], [-3453], ...], to the
        results from regex and postprocess. Note that the returned values
        are lists of lists, because you can grep multiple items on one line.
    """
    compiled = {key: re.compile(pattern, re.MULTILINE | re.DOTALL) for key, pattern in patterns.items()}
    matches = defaultdict(list)
    for key, pattern in compiled.items():
        for match in pattern.finditer(text_str):
            matches[key].append([postprocess(i) for i in match.groups()])
            if terminate_on_match:
                break
    return matches


def read_matrix_pattern(header_pattern, footer_pattern, elements_pattern, text, postprocess=str):
    """Parse a matrix to get the quantities in a numpy array."""
    # Get the piece of text between the header and the footer
    header_regex = re.compile(header_pattern)
    footer_regex = re.compile(footer_pattern)

    # Find the text between the header and footer
    text_between_header_and_footer = text[header_regex.search(text).end() : footer_regex.search(text).start()]

    # Get the elements
    elements = re.findall(elements_pattern, text_between_header_and_footer)

    # Apply postprocessing to all the elements
    return [postprocess(elem) for elem in elements]


def read_table_pattern(
    text_str,
    header_pattern,
    row_pattern,
    footer_pattern,
    postprocess=str,
    attribute_name=None,
    last_one_only=False,
):
    r"""Parse table-like data. A table composes of three parts: header,
    main body, footer. All the data matches "row pattern" in the main body
    will be returned.

    Args:
        text_str (str): the input string to search for patterns
        header_pattern (str): The regular expression pattern matches the
            table header. This pattern should match all the text
            immediately before the main body of the table. For multiple
            sections table match the text until the section of
            interest. MULTILINE and DOTALL options are enforced, as a
            result, the "." meta-character will also match "\n" in this
            section.
        row_pattern (str): The regular expression matches a single line in
            the table. Capture interested field using regular expression
            groups.
        footer_pattern (str): The regular expression matches the end of the
            table. E.g. a long dash line.
        postprocess (callable): A post processing function to convert all
            matches. Defaults to str, i.e., no change.
        attribute_name (str): Name of this table. If present the parsed data
            will be attached to "data. e.g. self.data["efg"] = [...]
        last_one_only (bool): All the tables will be parsed, if this option
            is set to True, only the last table will be returned. The
            enclosing list will be removed. i.e. Only a single table will
            be returned. Default to be True.

    Returns:
        List of tables. 1) A table is a list of rows. 2) A row if either a list of
        attribute values in case the capturing group is defined without name in
        row_pattern, or a dict in case that named capturing groups are defined by
        row_pattern.
    """
    table_pattern_text = header_pattern + r"\s*(?P<table_body>(?:" + row_pattern + r")+)\s*" + footer_pattern
    table_pattern = re.compile(table_pattern_text, re.MULTILINE | re.DOTALL)
    rp = re.compile(row_pattern)
    data = {}
    tables = []
    for mt in table_pattern.finditer(text_str):
        table_body_text = mt.group("table_body")
        table_contents = []
        for ml in rp.finditer(table_body_text):
            d = ml.groupdict()
            if len(d) > 0:
                processed_line = {k: postprocess(v) for k, v in d.items()}
            else:
                processed_line = [postprocess(v) for v in ml.groups()]
            table_contents.append(processed_line)
        tables.append(table_contents)
    retained_data = tables[-1] if last_one_only else tables
    if attribute_name is not None:
        data[attribute_name] = retained_data
        return data
    return retained_data


def lower_and_check_unique(dict_to_check):
    """
    Takes a dictionary and makes all the keys lower case. Also converts all numeric
    values (floats, ints) to str and replaces "jobtype" with "job_type" just so that
    key specifically can be called elsewhere without ambiguity. Finally, ensures that
    multiple identical keys, that differed only due to different capitalizations, are not
    present. If there are multiple equivalent keys, an Exception is raised.

    Args:
        dict_to_check (dict): The dictionary to check and standardize

    Returns:
        dict: An identical dictionary but with all keys made
            lower case and no identical keys present.
    """
    if dict_to_check is None:
        return None

    to_return = {}
    for key, val in dict_to_check.items():
        # lowercase the key
        new_key = key.lower()

        if isinstance(val, str):
            val = val.lower()
        elif isinstance(val, (int, float)):
            # convert all numeric keys to str
            val = str(val)
        else:
            pass

        if new_key == "jobtype":
            new_key = "job_type"

        if new_key in to_return and val != to_return[new_key]:
            raise ValueError(f"Multiple instances of key {new_key} found with different values! Exiting...")

        to_return[new_key] = val
    return to_return


def process_parsed_coords(coords):
    """Takes a set of parsed coordinates, which come as an array of strings,
    and returns a numpy array of floats.
    """
    geometry = np.zeros(shape=(len(coords), 3), dtype=float)
    for ii, entry in enumerate(coords):
        for jj in range(3):
            geometry[ii, jj] = float(entry[jj])
    return geometry


def process_parsed_fock_matrix(fock_matrix):
    """The Fock matrix is parsed as a list, while it should actually be
    a square matrix, this function takes the list of finds the right dimensions
    in order to reshape the matrix.
    """
    total_elements = len(fock_matrix)
    n_rows = int(np.sqrt(total_elements))
    n_cols = n_rows

    # Q-Chem splits the printing of the matrix into chunks of 6 elements
    # per line. TODO: Is there a better way than to hard-code this?
    chunks = 6 * n_rows
    # Decide the indices of the chunks
    chunk_indices = np.arange(chunks, total_elements, chunks)
    # Split the arrays into the chunks
    fock_matrix_chunks = np.split(fock_matrix, chunk_indices)

    # Reshape the chunks into the matrix and populate the matrix
    fock_matrix_reshaped = np.zeros(shape=(n_rows, n_cols), dtype=float)
    index_cols = 0
    for fock_matrix_chunk in fock_matrix_chunks:
        n_cols_chunks = len(fock_matrix_chunk) / n_rows
        n_cols_chunks = int(n_cols_chunks)
        fock_matrix_chunk_reshaped = np.reshape(fock_matrix_chunk, (n_rows, n_cols_chunks))
        fock_matrix_reshaped[:, index_cols : index_cols + n_cols_chunks] = fock_matrix_chunk_reshaped
        index_cols += n_cols_chunks

    return fock_matrix_reshaped


def process_parsed_hess(hess_data):
    """
    Takes the information contained in a HESS file and converts it into
    the format of the machine-readable 132.0 file which can be printed
    out to be read into subsequent optimizations.
    """
    dim = int(hess_data[1].split()[1])
    hess = [[0 for _ in range(dim)] for _ in range(dim)]

    row = 0
    column = 0
    for ii, line in enumerate(hess_data):
        if ii not in [0, 1, len(hess_data) - 1]:
            split_line = line.split()
            for val in split_line:
                num = float(val)
                hess[row][column] = num
                if row == column:
                    row += 1
                    column = 0
                else:
                    hess[column][row] = num
                    column += 1

    processed_hess_data = []
    for ii in range(dim):
        for jj in range(dim):
            processed_hess_data.append(hess[ii][jj])

    return processed_hess_data
