import dataclasses
import json
from typing import ClassVar, Dict, Iterable, Iterator, List, Optional, Tuple, Union

import pymupdf
from openai.types.chat.chat_completion_message_param import ChatCompletionMessageParam

from domain.chunk_d import DocumentD
from extraction_pipeline.document_metadata_extractor.document_metadata_extractor import (
    DocumentMetadataExtractor,)
from extraction_pipeline.document_metadata_extractor.prompts import (
    DOCUMENT_METADATA_PROMPT,)
from llm_handler.llm_interface import LLMInterface
from llm_handler.openai_handler import ChatModelVersion, OpenAIHandler
from utils.dates import parse_date


class CreationDateError(Exception):
    pass


class AuthorsError(Exception):
    pass


class OpenAIDocumentMetadataExtractor(DocumentMetadataExtractor):

    _handler: LLMInterface
    _MODEL_VERSION: ChatModelVersion = ChatModelVersion.GPT_4_O
    _AUTHORS_KEY: ClassVar[str] = "authors"
    _PUBLISH_DATE_KEY: ClassVar[str] = "publish_date"
    _TEMPARATURE: ClassVar[float] = 0.2

    def __init__(self,
                 openai_handler: Optional[LLMInterface] = None,
                 model_version: Optional[ChatModelVersion] = None):
        self._handler = openai_handler or OpenAIHandler()
        self._model_version = model_version or self._MODEL_VERSION

    def _validate_text(self, completion_text: Dict[str, Union[str, List[str]]]):
        if not completion_text.get(self._AUTHORS_KEY):
            raise AuthorsError("No authors found.")
        if not completion_text.get(self._PUBLISH_DATE_KEY):
            raise CreationDateError("No creation date found.")

        publish_date_str: str = str(completion_text.get(self._PUBLISH_DATE_KEY, ""))
        try:
            parse_date(publish_date_str)
        except ValueError as e:
            raise CreationDateError(
                f"Failed to parse publish date '{publish_date_str}': {e}") from e

    def _process_element(self, element: DocumentD) -> Iterable[DocumentD]:
        pdf_document_pages: Iterator = pymupdf.open(element.file_path).pages()
        first_page_text: str = next(pdf_document_pages).get_text()
        messages: List[ChatCompletionMessageParam] = [{
            "role": "system", "content": DOCUMENT_METADATA_PROMPT
        },
                                                      {
                                                          "role": "user",
                                                          "content": f"Input:\n{first_page_text}"
                                                      }]
        completion_text_raw = self._handler.get_chat_completion(
            messages=messages,
            model=self._model_version,
            temperature=self._TEMPARATURE,
            response_format={"type": "json_object"})
        completion_text: Dict[str, Union[str, List[str]]] = dict(json.loads(completion_text_raw))
        self._validate_text(completion_text)
        authors: str = ", ".join(completion_text.get(self._AUTHORS_KEY, []))
        publish_date: str = str(completion_text.get(self._PUBLISH_DATE_KEY, ""))

        yield dataclasses.replace(element, authors=authors, publish_date=publish_date)