# ============================================================
# Real Effort Task (RET) generator: Decoding Task
# ============================================================

import random
from random import randint
from string import digits, ascii_lowercase
import logging

logger = logging.getLogger(__name__)


# ------------------------------------------------------------
# Utility Functions
# ------------------------------------------------------------

def slicelist(lst, n):
    """Split list into sublists of length n (if possible)."""
    return [lst[i:i + n] for i in range(0, len(lst), n)]


def chunkify(lst, n):
    """Split list into n roughly equal-sized chunks."""
    return [lst[i::n] for i in range(n)]


def get_random_list(max_len):
    """Generate a random list of integers (unused for decoding, kept for flexibility)."""
    low_upper_bound = 50
    high_upper_bound = 99
    return [randint(10, randint(low_upper_bound, high_upper_bound)) for _ in range(max_len)]


# ------------------------------------------------------------
# Base Task Generator Class
# ------------------------------------------------------------

class TaskGenerator:
    """Base class for real effort tasks like Decoding or Slider."""

    def __init__(self, **kwargs):
        # Generate body + correct answer
        self.body = self.get_body(**kwargs)
        self.correct_answer = self.get_correct_answer()
        logger.debug(f'Generated task: {self.body}, answer: {self.correct_answer}')

    def get_body(self, **kwargs):
        """To be implemented by each subclass."""
        raise NotImplementedError("Subclasses must implement get_body()")

    def get_correct_answer(self):
        """To be implemented by each subclass."""
        raise NotImplementedError("Subclasses must implement get_correct_answer()")

    def get_context_for_body(self):
        """Return the context dictionary for templates."""
        return {}


# ------------------------------------------------------------
# Decoding Task Generator
# ------------------------------------------------------------

class Decoding(TaskGenerator):
    """Generate a decoding task: translate digits to letters."""

    name = 'Decoding'

    def get_body(self, **kwargs):
        """Generate the random decoding dictionary and question."""
        dict_length = kwargs.get('dict_length', 10)  # number of pairs (e.g., 10 letters)
        task_len = kwargs.get('task_len', 2)         # number of digits to decode

        # Create random digit-letter mappings
        digits_list = random.sample(list(digits), k=dict_length)
        random.shuffle(digits_list)
        letters_list = random.sample(ascii_lowercase, k=dict_length)

        self.task_dict = dict(zip(digits_list, letters_list))
        self.question = random.choices(digits_list, k=task_len)

        return {
            'question': self.question,
            'task_dict': self.task_dict,
        }

    def get_correct_answer(self):
        """Compute the correct decoded string."""
        return ''.join([self.task_dict[i] for i in self.question])

    def get_context_for_body(self):
        """Context for rendering in oTree templates."""
        return {
            'question': self.question,
            'task_dict': self.task_dict,
        }