"""Strict model-owned repetition, with no implicit switch to single-read mode."""
from .prompt_dyno import state_messages, options_of, render_value, DEFAULT_QUESTION, INSTRUCTION, ANSWER, render

READ_AGAIN = 'Read the same input again before answering:\n\n'


class LengthError(ValueError):
    pass


def render_twice(processor, state, question, labels):
    messages, media = state_messages(state)
    if media: raise ValueError('This release is text-only')
    keys, texts = options_of(question)
    head = (render_value(question['instructions'])
            if question.get('instructions') is not None else DEFAULT_QUESTION)
    options = '\n'.join(f'{labels[i]}. {value}' for i, value in enumerate(texts))
    ask = INSTRUCTION + f'\n\nQuestion: {head}\nOptions:\n{options}'
    first = [dict(m) for m in messages] + [{'role': 'user', 'content': ask}]
    again = [dict(m) for m in first if m.get('role') != 'system']
    if again[0]['role'] == 'user':
        content = again[0].get('content')
        content = ([{'type': 'text', 'text': READ_AGAIN}] + content
                   if isinstance(content, list) else READ_AGAIN + (content or ''))
        again[0] = {**again[0], 'content': content}
    else: again.insert(0, {'role': 'user', 'content': READ_AGAIN.rstrip()})
    text = processor.apply_chat_template(first + again, tokenize=False,
                                        add_generation_prompt=True, enable_thinking=False)
    return text + ANSWER, keys


def encode(processor, labels, label_ids, request, mode='default', limit=16384):
    if mode not in ('default', 'flash'): raise ValueError('mode must be default or flash')
    if not isinstance(request, dict) or 'state' not in request:
        raise ValueError('Pass a structured decision request with state and question(s)')
    if request.get('images'): raise ValueError('This release is text-only')
    questions = request.get('questions')
    if questions is None: questions = {'q': request['question']}
    if not isinstance(questions, dict) or not questions: raise ValueError('Empty questions')
    _, once, media = render(processor, request['state'], questions, labels)
    if media: raise ValueError('This release is text-only')
    output = []
    for key, question in questions.items():
        text, keys = (render_twice(processor, request['state'], question, labels)
                      if mode == 'default' else once[key])
        if keys != once[key][1]: raise ValueError('Option order changed')
        if len(keys) > len(label_ids): raise ValueError('Unsupported option count')
        ids = processor.tokenizer.encode(text, add_special_tokens=False)
        if not 1 <= len(ids) <= limit:
            raise LengthError(f'{mode} rendered sequence has {len(ids)} tokens; limit {limit}. '
                              'No truncation or automatic flash fallback. Shorten input or explicitly request mode="flash".')
        # Check the actual continuation boundary, including user-controlled text.
        for label, token in zip(labels[:len(keys)], label_ids[:len(keys)]):
            if processor.tokenizer.encode(text+' '+label, add_special_tokens=False) != ids+[token]:
                raise ValueError('Answer label is not one token at the actual prompt boundary')
        output.append({'qid': key, 'ids': ids, 'keys': keys, 'kind': question['type']})
    return output