"""Insert into string according to a pattern

https://github.com/yongchao98/CodeSteer-v1.0/blob/main/create_dataset/create_dataset_string_insertion.py
"""

from dataclasses import dataclass
from random import Random
from typing import Any, Optional

from ..factory import ProceduralDataset, register_dataset

QUESTION_TEMPLATE = """Given a string consisting of characters A, B, C, D, and E, your job is to insert a character according to the following pattern:
1. If there is a substring ABCD in the string, insert the character A after the substring.
2. If there is a substring BCDE in the string, insert the character B after the substring.
3. If there is a substring CDEA in the string, insert the character C after the substring.
4. If there is a substring DEAB in the string, insert the character D after the substring.
5. If there is a substring EABC in the string, insert the character E after the substring.

Once you have inserted a character, you have to skip over the substring and the inserted character and continue the search from the next character.

Example
- Input: DDABCDEEDEAB
- Output: DDABCDAEEDEABD
- Explanation:
    - Theere are two inserted characters: DDABCD[A]EEDEAB[D] (shown in square brackets)
    - First, we insert A after ABCD.
    - Even though with the newly inserted 'A' we can obtain the substring BCD[A], we can't use it to insert another character.
    - Lastly, we insert D after DEAB.
    - Therefore, the final answer is DDABCDAEEDEABD (represented as a string, instead of a list of characters).

Given the following string, provide the answer after inserting the characters according to the pattern: {string}
"""


@dataclass
class StringInsertionConfig:
    """Configuration for String Insertion dataset generation"""

    min_string_length: int = 5  # Minimum string length
    max_string_length: int = 20  # Maximum string length

    size: int = 500  # Virtual dataset size
    seed: Optional[int] = None

    def validate(self):
        """Validate configuration parameters"""
        assert 5 <= self.min_string_length, "Minimum string length should be at least 5"
        assert self.min_string_length <= self.max_string_length, "Minimum string length should be less than maximum"


class StringInsertionDataset(ProceduralDataset):
    """Generates String Insertion exercises with configurable difficulty"""

    def __init__(self, config: StringInsertionConfig):
        super().__init__(config=config, seed=config.seed, size=config.size)
        self.vocabulary = ["A", "B", "C", "D", "E"]
        self.insertion_rules = [
            ("ABCD", "A"),
            ("BCDE", "B"),
            ("CDEA", "C"),
            ("DEAB", "D"),
            ("EABC", "E"),
        ]

    def _get_answer(self, string: str) -> str:
        """Apply insertion rules to a string"""
        output = []
        i = 0
        while i < len(string):
            inserted = False
            for pattern, char in self.insertion_rules:
                substring = string[i : i + len(pattern)]
                if substring == pattern:
                    output.append(substring + char)
                    i += len(pattern)
                    inserted = True
                    break
            if not inserted:
                output.append(string[i])
                i += 1
        return "".join(output)

    def score_answer(self, answer: Optional[str], entry: dict[str, Any]) -> float:
        """Overwrite this method in derived classes if a single oracle answer is not available."""
        oracle_answer = entry["answer"]
        if answer is not None:
            if answer == oracle_answer:
                return 1.0
            else:
                try:
                    # check if answer is python list of characters
                    answer = "".join(eval(answer))
                    if answer == oracle_answer:
                        return 0.5
                except Exception as e:
                    return 0.01
        return 0.0

    def __getitem__(self, idx: int) -> dict:
        """Generate a single String Insertion question"""
        rng = Random(self.seed + idx)

        string_length = rng.randint(self.config.min_string_length, self.config.max_string_length)
        string = "".join(rng.choice(self.vocabulary) for _ in range(string_length))

        answer = self._get_answer(string)

        return {
            "question": QUESTION_TEMPLATE.format(string=string),
            "answer": str(answer),
            "metadata": {"string": string, "solution": answer},
        }


register_dataset("string_insertion", StringInsertionDataset, StringInsertionConfig)