# -----------------------------------------------------------------------------
# Author: Jiawei Liu
# Date: 2025-10-29
# -----------------------------------------------------------------------------
import re
import json

from tqdm import tqdm
from loguru import logger

from pathlib import Path
from typing import Tuple, List


project_root = Path(__file__).parent.parent.parent

problem_tag = "Problem"
solution_tag = "Solution"


def clean_text(text: str) -> str:
    """
    Clean the input text by removing unwanted characters and normalizing spaces.

    Args:
        text (str): The input markdown text.
    Returns:
        str: The cleaned text.
    """
    text = text.replace("www.mathsolympiad.org.nz", "")
    return text.strip()


def analyze(text: str) -> Tuple[List, int]:
    """
    Analyze the text and return the tags and problem number.

    Args:
        text (str): The markdown text to analyze.

    Returns:
        Tuple[List, int]: A tuple containing the tags and problem number.
    """
    problem_pattern = re.compile(
        r"(?:\n|# )(?:(\d+)\.\sProblem\:?|(\d+)\.)", re.IGNORECASE
    )
    solution_pattern = re.compile(
        r"(?:\n|#\s*)(?:Solution|FIRST SOLUTION|SECOND SOLUTION|THIRD SOLUTION|Solution.*?\:|Alternative Solution.*?\:)",
        re.IGNORECASE,
    )

    tags = []
    tags.extend([(x, problem_tag) for x in problem_pattern.finditer(text)])
    problem_num = len(tags)

    tags.extend([(x, solution_tag) for x in solution_pattern.finditer(text)])
    tags.sort(key=lambda x: x[0].start())
    return tags, problem_num


def segment(text: str, tags):
    starts = []
    ends = []

    for i in range(len(tags)):
        starts.append(tags[i][0].end())
        if i + 1 < len(tags):
            ends.append(tags[i + 1][0].start())
        else:
            ends.append(len(text))

    return [
        text[start:end].strip().strip("#").strip() for start, end in zip(starts, ends)
    ]


def join(tags, segments):
    problem, solution = "", ""
    problem_label, problem_match, solution_match = "", "", ""
    pairs = []

    for tag, segment in zip(tags, segments):
        if tag[1] == problem_tag:
            problem = segment
            problem_match = tag[0].group(0)
            problem_label = tag[0].group(1) or tag[0].group(2)
        else:
            solution = segment
            solution_match = tag[0].group(0)
            pairs.append(
                (problem, solution, problem_label, problem_match, solution_match)
            )

    return pairs


def write_pairs(output_file: Path, pairs):
    year = re.search(r"(\d{4})", output_file.stem).group(1)

    output_jsonl_text = ""
    for problem, solution, problem_label, problem_match, solution_match in pairs:
        output_jsonl_text += (
            json.dumps(
                {
                    "year": year,
                    "tier": "T1",
                    "problem_label": problem_label,
                    "problem_type": None,
                    "exam": "NewZealand_MO",
                    "problem": problem,
                    "solution": solution,
                    "metadata": {
                        "resource_path": output_file.relative_to(
                            project_root
                        ).as_posix(),
                        "problem_match": problem_match,
                        "solution_match": solution_match,
                    },
                },
                ensure_ascii=False,
            )
            + "\n"
        )

    output_file.write_text(output_jsonl_text, encoding="utf-8")


def main():
    compet_base_path = Path(__file__).resolve().parent.parent
    compet_md_path = compet_base_path / "md"
    seg_output_path = compet_base_path / "segmented"

    total_problem_count = 0
    total_solution_count = 0

    for nzmo_md in tqdm(list(compet_md_path.glob("**/*.md")), desc="Segmenting"):
        output_file = seg_output_path / nzmo_md.relative_to(compet_md_path).with_suffix(
            ".jsonl"
        )
        output_file.parent.mkdir(parents=True, exist_ok=True)

        text = "\n" + clean_text(nzmo_md.read_text(encoding="utf-8"))

        tags, problem_num = analyze(text)

        segments = segment(text, tags)
        pairs = join(tags, segments)
        if pairs and problem_num > 0:
            write_pairs(output_file, pairs)

            total_problem_count += problem_num
            total_solution_count += len(pairs)
        else:
            logger.warning(f"No problem found in {nzmo_md}")

    logger.info(f"Total problem count: {total_problem_count}")
    logger.info(f"Total solution count: {total_solution_count}")


if __name__ == "__main__":
    main()