import json
from dataclasses import asdict
from pathlib import Path
from typing import Iterator

from dateutil.parser import parse
from langchain.docstore.document import Document
from langchain.document_loaders.base import BaseLoader

from models import WikiPage


def date_to_int(dt_str: str) -> int:
    dt = parse(dt_str)
    return int(dt.timestamp())


def get_contents(inputfile: Path) -> Iterator[tuple[WikiPage, str]]:
    """filename for file with ndjson

        {"id": <page_id>, "title": <page title>, "content": <page body>, "ctime": ..., "user": <name>, "url": "https:..."}
        {"title": ...}
    """
    with inputfile.open("r") as f:
        obj = [json.loads(line) for line in f]
    for data in obj:
        title = data["title"]
        body = data["content"]
        ctime = date_to_int(data["ctime"]) if isinstance(data["ctime"], str) else data["ctime"]
        doc = WikiPage(
            id=data["id"],
            title=title,
            ctime=ctime,
            user=data["user"],
            url=data["url"],
        )
        text = title
        if body:
            text += "\n\n" + body
        yield doc, text


class WikiPageLoader(BaseLoader):
    def __init__(self, inputfile: Path):
        self.inputfile = inputfile

    def lazy_load(self) -> Iterator[Document]:
        for doc, text in get_contents(self.inputfile):
            metadata = asdict(doc)
            yield Document(page_content=text, metadata=metadata)

    def load(self) -> list[Document]:
        return list(self.lazy_load())