# Copyright (c) Meta Platforms, Inc. and affiliates.

# This source code is licensed under the MIT license found in the
# LICENSE file in the root directory of this source tree.

import re
import numpy as np


def extract_solution(solution_str):
    answer_pattern = r"<answer>(.*?)</answer>"
    matches = re.findall(answer_pattern, solution_str, re.DOTALL)
    if matches:
        final_answer = matches[-1].strip()
    else:
        final_answer = None
    return final_answer


def validate_equation(equation_str, available_numbers):
    """Validate that equation only uses available numbers and each number once."""
    try:
        # Extract all numbers from the equation
        numbers_in_eq = [int(n) for n in re.findall(r"\d+", equation_str)]

        # Check if all numbers in equation are available
        available_numbers = sorted(available_numbers)
        numbers_in_eq = sorted(numbers_in_eq)

        # Each number should be used exactly once
        return numbers_in_eq == available_numbers
    except:
        return False


def evaluate_equation(equation_str):
    """Safely evaluate the arithmetic equation using eval() with precautions."""
    try:
        # Define a regex pattern that only allows numbers, operators, parentheses, and whitespace
        allowed_pattern = r"^[\d+\-*/().\s]+$"
        if not re.match(allowed_pattern, equation_str):
            raise ValueError("Invalid characters in equation.")

        # Evaluate the equation with restricted globals and locals
        result = eval(equation_str, {"__builtins__": None}, {})
        return result
    except Exception as e:
        return None


def compute_score(solution_str, ground_truth, method="strict", format_score=0.1, score=1.0):
    """The scoring function for countdown task.

    Args:
        solution_str: the solution text
        ground_truth: dictionary containing target number and available numbers
        method: the method to extract the solution
        format_score: the score for correct format but wrong answer
        score: the score for the correct answer
    """
    target = ground_truth["target"]
    numbers = ground_truth["numbers"]

    equation = extract_solution(solution_str=solution_str)
    if "wait" in solution_str:
        do_print = True
    do_print = np.random.rand() < 0.4
    if do_print:
        print(f"--------------------------------")
        print(f"Target: {target} | Numbers: {numbers}")
        print(f"Extracted equation: {equation}")
        print(f"Solution string: {solution_str}")

    if equation is None:
        if do_print:
            print(f"No equation found")
        return 0

    # Validate equation uses correct numbers
    if not validate_equation(equation, numbers):
        if do_print:
            print(f"Invalid equation")
        return format_score

    # Evaluate equation
    try:
        result = evaluate_equation(equation)
        if result is None:
            if do_print:
                print(f"Could not evaluate equation")
            return format_score

        if abs(result - target) < 1e-5:  # Account for floating point precision
            if do_print:
                print(f"Correct equation: {equation} = {result}")
            return score
        else:
            if do_print:
                print(f"Wrong result: equation = {result}, target = {target}")
            return format_score
    except:
        if do_print:
            print(f"Error evaluating equation")
        return format_score


class Parser:
    @classmethod
    def extract_answer_gsm8k(cls, generated_text):
        """Extract the first numerical answer following '####' in the generated text."""
        try:
            # Use regex to find the first occurrence of #### followed by a number
            # Handle formats like: #### 18, #### $18, #### 18.0
            match = re.search(r"####\s*\$?([\d,]+(?:\.\d+)?)", generated_text)
            if match:
                return float(match.group(1).replace(",", ""))
        except Exception as e:
            print(f"Error extracting answer: {e}, Text: {generated_text[:100]}")
        return None

    @classmethod
    def extract_answer_boxed(cls, generated_text):
        """Extract the first numerical answer following '####' in the generated text."""
        try:
            pred = remove_boxed(last_boxed_only_string(generated_text))
        except:
            pred = generated_text
        return pred

    @classmethod
    def extract_answer_boxed_ctd(cls, generated_text):
        """Extract the first numerical answer following '####' in the generated text."""
        pred = Parser.extract_answer_boxed(generated_text)
        pred = pred.replace(r"\div", "/").replace("\times", "*").replace(r"\cdot", "*")
        return pred

    @classmethod
    def extract_answer_grpo_ctd(cls, generated_text):
        """Extract the first numerical answer following '####' in the generated text."""
        pred = extract_solution(generated_text)
        print(generated_text)
        print(pred)
        if pred is not None:

            pred = pred.replace(r"\div", "/").replace("\times", "*").replace(r"\cdot", "*")

        return pred

    @classmethod
    def extract_answer_sudoku(cls, solution_str):
        """Extract the Sudoku solution from the generated text."""
        answer_pattern = r"<answer>(.*?)</answer>"
        matches = re.findall(answer_pattern, solution_str, re.DOTALL)
        if matches:
            # Get the last answer tag content, strip whitespace and newlines
            final_answer = re.sub(r"\s", "", matches[-1].strip())
            return final_answer
        return None


def is_equiv(str1, str2, verbose=False):
    if type(str1) == float or type(str2) == float:
        try:
            return abs(float(str1) - float(str2)) < 1e-6
        except:
            return False
    if str1 is None and str2 is None:
        print("WARNING: Both None")
        return True
    if str1 is None or str2 is None:
        return False

    try:
        ss1 = strip_string(str1)
        ss2 = strip_string(str2)
        if verbose:
            print(ss1, ss2)
        return ss1 == ss2
    except Exception:
        return str1 == str2


def remove_boxed(s):
    if "\\boxed " in s:
        left = "\\boxed "
        assert s[: len(left)] == left
        return s[len(left) :]

    left = "\\boxed{"

    try:
        assert s[: len(left)] == left
        assert s[-1] == "}"

        return s[len(left) : -1]
    except:
        return s


def last_boxed_only_string(string):
    idx = string.rfind("\\boxed")
    if "\\boxed " in string:
        return "\\boxed " + string.split("\\boxed ")[-1].split("$")[0]
    if idx < 0:
        idx = string.rfind("\\fbox")
        if idx < 0:
            return string

    i = idx
    right_brace_idx = None
    num_left_braces_open = 0
    while i < len(string):
        if string[i] == "{":
            num_left_braces_open += 1
        if string[i] == "}":
            num_left_braces_open -= 1
            if num_left_braces_open == 0:
                right_brace_idx = i
                break
        i += 1

    if right_brace_idx is None:
        retval = None
    else:
        retval = string[idx : right_brace_idx + 1]

    return retval


def fix_fracs(string):
    substrs = string.split("\\frac")
    new_str = substrs[0]
    if len(substrs) > 1:
        substrs = substrs[1:]
        for substr in substrs:
            new_str += "\\frac"
            if substr[0] == "{":
                new_str += substr
            else:
                try:
                    assert len(substr) >= 2
                except AssertionError:
                    return string
                a = substr[0]
                b = substr[1]
                if b != "{":
                    if len(substr) > 2:
                        post_substr = substr[2:]
                        new_str += "{" + a + "}{" + b + "}" + post_substr
                    else:
                        new_str += "{" + a + "}{" + b + "}"
                else:
                    if len(substr) > 2:
                        post_substr = substr[2:]
                        new_str += "{" + a + "}" + b + post_substr
                    else:
                        new_str += "{" + a + "}" + b
    string = new_str
    return string


def fix_a_slash_b(string):
    if len(string.split("/")) != 2:
        return string
    a = string.split("/")[0]
    b = string.split("/")[1]
    try:
        a = int(a)
        b = int(b)
        assert string == "{}/{}".format(a, b)
        new_string = "\\frac{" + str(a) + "}{" + str(b) + "}"
        return new_string
    except AssertionError:
        return string


def remove_right_units(string):
    # "\\text{ " only ever occurs (at least in the val set) when describing units
    if "\\text{ " in string:
        splits = string.split("\\text{ ")
        assert len(splits) == 2
        return splits[0]
    else:
        return string


def fix_sqrt(string):
    if "\\sqrt" not in string:
        return string
    splits = string.split("\\sqrt")
    new_string = splits[0]
    for split in splits[1:]:
        if split[0] != "{":
            a = split[0]
            new_substr = "\\sqrt{" + a + "}" + split[1:]
        else:
            new_substr = "\\sqrt" + split
        new_string += new_substr
    return new_string


def strip_string(string):
    # linebreaks
    string = string.replace("\n", "")

    # remove inverse spaces
    string = string.replace("\\!", "")

    # replace \\ with \
    string = string.replace("\\\\", "\\")

    # replace tfrac and dfrac with frac
    string = string.replace("tfrac", "frac")
    string = string.replace("dfrac", "frac")

    # remove \left and \right
    string = string.replace("\\left", "")
    string = string.replace("\\right", "")

    # Remove circ (degrees)
    string = string.replace("^{\\circ}", "")
    string = string.replace("^\\circ", "")

    # remove dollar signs
    string = string.replace("\\$", "")

    # remove units (on the right)
    string = remove_right_units(string)

    # remove percentage
    string = string.replace("\\%", "")
    string = string.replace("\%", "")  # noqa: W605

    # " 0." equivalent to " ." and "{0." equivalent to "{." Alternatively, add "0" if "." is the start of the string
    string = string.replace(" .", " 0.")
    string = string.replace("{.", "{0.")
    # if empty, return empty string
    if len(string) == 0:
        return string
    if string[0] == ".":
        string = "0" + string

    # to consider: get rid of e.g. "k = " or "q = " at beginning
    if len(string.split("=")) == 2:
        if len(string.split("=")[0]) <= 2:
            string = string.split("=")[1]

    # fix sqrt3 --> sqrt{3}
    string = fix_sqrt(string)

    # remove spaces
    string = string.replace(" ", "")

    # \frac1b or \frac12 --> \frac{1}{b} and \frac{1}{2}, etc. Even works with \frac1{72} (but not \frac{72}1). Also does a/b --> \\frac{a}{b}
    string = fix_fracs(string)

    # manually change 0.5 --> \frac{1}{2}
    if string == "0.5":
        string = "\\frac{1}{2}"

    # NOTE: X/Y changed to \frac{X}{Y} in dataset, but in simple cases fix in case the model output is X/Y
    string = fix_a_slash_b(string)

    return string


def validate_equation(equation_str, available_numbers):
    """Validate that equation only uses available numbers and each number once."""
    try:
        # Extract all numbers from the equation
        numbers_in_eq = [int(n) for n in re.findall(r"\d+", equation_str)]

        # Check if all numbers in equation are available
        available_numbers = sorted(available_numbers)
        numbers_in_eq = sorted(numbers_in_eq)

        # Each number should be used exactly once
        return numbers_in_eq == available_numbers
    except:
        return False


def evaluate_equation(equation_str):
    """Safely evaluate the arithmetic equation using eval() with precautions."""
    try:
        # Define a regex pattern that only allows numbers, operators, parentheses, and whitespace
        allowed_pattern = r"^[\d+\-*/().\s]+$"
        if not re.match(allowed_pattern, equation_str):
            raise ValueError("Invalid characters in equation.")

        # Evaluate the equation with restricted globals and locals
        result = eval(equation_str.strip(), {"__builtins__": None}, {})
        return result
    except Exception as e:
        return float("Inf")