import os
import re

import crossref_commons.retrieval as crossref
import pymupdf
import pymupdf4llm
from semantic_text_splitter import MarkdownSplitter

from _arango import ArangoDB
from _chromadb import ChromaDB

arango = ArangoDB()
chromadb = ChromaDB()

# Initialize the chroma database
chroma_col = chromadb.db.get_collection("sci_articles")
max_characters = 2200
ts = MarkdownSplitter(max_characters)
path_folder = "sci_articles"

def get_crossref(doi):
    try:
        work = crossref.get_publication_as_json(doi)

        # Determine the best publication date
        if "published-print" in work:
            publication_date = work["published-print"]["date-parts"][0]
        elif "published-online" in work:
            publication_date = work["published-online"]["date-parts"][0]
        elif "issued" in work:
            publication_date = work["issued"]["date-parts"][0]
        else:
            publication_date = [None]
        publication_year = publication_date[0]

        metadata = {
            "doi": work.get("DOI", None),
            "title": work.get("title", [None])[
                0
            ],  # Extract the first title if available
            "authors": [
                f"{author['given']} {author['family']}"
                for author in work.get("author", [])
            ],
            "abstract": work.get("abstract", None),
            "journal": work.get("container-title", [None])[
                0
            ],  # Extract the first journal title if available
            "volume": work.get("volume", None),
            "issue": work.get("issue", None),
            "pages": work.get("page", None),
            "published_date": "-".join(
                map(str, publication_date)
            ),  # Join date parts with hyphens
            "published_year": publication_year,
            "url_doi": work.get("URL", None),
            "link": (
                work.get("link", [None])[0]["URL"] if work.get("link", None) else None
            ),
            "language": work.get("language", None),
        } 
        return metadata
    except Exception as e:
        print(f"Error retrieving metadata for DOI {doi}: {e}")
        return None



def extract_doi(text):
    # Define the regex pattern for DOI
    doi_pattern = r"10\.\d{4,9}/[-._;()/:A-Za-z0-9]+"
    # Find the first doi in the text, if there is any
    doi = re.search(doi_pattern, text)
    if doi:
        # Return the first doi found
        doi = doi.group()
        doi = doi.strip('.').replace('.pdf', '')
        return doi
    else:
        return None


def process_pdf(pdf):
    if '/' not in pdf:
        pdf_path = os.path.join("sci_articles", pdf)
    else:
        pdf_path = pdf
    if extract_doi(pdf):
        doi = extract_doi(pdf)
    else:
        text = '\n'.join(pymupdf.get_text(pdf_path))
        doi = extract_doi(text)
        if not doi:
            print(f"\nCould not find DOI for {pdf}\n")
            return

    if arango.db.collection("sci_articles").get(arango.fix_key(doi)):
        print(f"Article {doi} already in database")
        return
    
    # Get metadata from Crossref
    crossref_info = get_crossref(doi)

    # Extract text from PDF
    md_pages = pymupdf4llm.to_markdown(pdf_path, page_chunks=True, show_progress=False)
    md_text = ""
    for page in md_pages:
        md_text += f"{page['text'].strip()}\n@{page['metadata']['page']}@\n"

    # Remove multiple '--' in text
    md_text = re.sub(r"[-]{3,}", "", md_text)
    md_text = re.sub(r"\n{3,}", "\n\n", md_text)
    better_chunks = []
    chunks = ts.chunks(md_text)
    # Merge chunks that are too short
    for chunk in chunks:
        if len(chunk) < 80:  # Get rid of short chunks like headers
            continue
        elif all(
            [
                len(chunk) < int(max_characters / 3),  # TODO Are those values good?
                len(chunks[-1]) < int(max_characters * 1.5),
                len(better_chunks) > 0,
            ]
        ):
            better_chunks[-1] += chunk
        else:
            better_chunks.append(chunk.strip())

    # Lists for ChromaDB
    ids = []
    documents = []
    metadatas = []

    # List for ArangoDB
    arango_chunks = []

    # Create page references and append to lists
    last_page = 1
    for i, chunk in enumerate(better_chunks):
        page_numbers = re.findall(r"@(\d+)@", chunk)
        if page_numbers == []:
            page_numbers = [last_page]
        else:
            last_page = page_numbers[-1]
        id = arango.fix_key(doi) + f"_{i}"
        ids.append(id)
        metadatas.append(
            {
                "_key": arango.fix_key(doi),
                "doi": doi,
                "file": f"sci_articles/{doi}.pdf",
                "chunk_nr": i,
                "pages": ",".join([str(i) for i in page_numbers]),
            }
        )
        chunk = re.sub(r"@(\d+)@", "", chunk)
        documents.append(chunk)
        arango_chunks.append({"text": chunk, "pages": page_numbers})
    chroma_col.add(ids=ids, documents=documents, metadatas=metadatas)
    arango_document = {
        "_key": arango.fix_key(doi),
        "doi": doi,
        "file": f"sci_articles/{doi}.pdf",
        "chunks": arango_chunks,
        "text": md_text,
        "metadata": crossref_info,
    }
    arango.db.collection("sci_articles").insert(
        arango_document, overwrite=True, overwrite_mode="update"
    )
    print(f"Inserted article {doi} into database")
    return doi


def add_pdfs(path_folder):
    pdf_in_folder = [file for file in os.listdir(path_folder) if file.endswith(".pdf")]
    for pdf in pdf_in_folder:
        process_pdf(pdf)


if __name__ == "__main__":

    
    add_pdfs(path_folder)