import multiprocessing as mp
import os
import random
import string

import click

from unstructured.ingest.connector.s3_connector import S3Connector, SimpleS3Config
from unstructured.ingest.doc_processor.generalized import initialize, process_document

class MainProcess:

    def __init__(self, doc_connector, doc_processor_fn, num_processes, reprocess):
        # initialize the reader and writer
        self.doc_connector = doc_connector
        self.doc_processor_fn = doc_processor_fn
        self.num_processes = num_processes
        self.reprocess = reprocess

    def initialize(self):
        """Slower initialization things: check connections, load things into memory, etc."""
        initialize()
        
    def cleanup(self):
        self.doc_connector.cleanup()

    def _filter_docs_with_outputs(self, docs):
        num_docs_all = len(docs)
        docs = [doc for doc in docs if not doc.has_output()]
        num_docs_to_process = len(docs)
        if num_docs_to_process == 0:
            print("All docs have structured outputs, nothing to do. Use --reprocess to process all.")
            return None
        elif num_docs_to_process != num_docs_all:
            print(f"Skipping processing for {num_docs_all - num_docs_to_process} docs out of "
                  f"{num_docs_all} since their structured outputs already exist, use --reprocess to "
                  "reprocess those in addition to the unprocessed ones.")
        return docs
        
    def run(self):
        self.initialize()
        
        self.doc_connector.fetch_docs()

        # fetch the list of lazy downloading IngestDoc obj's
        docs = self.doc_connector.fetch_docs()

        # remove docs that have already been processed
        if not self.reprocess:
            docs = self._filter_docs_with_outputs(docs)
            if not docs:
                return
            
        # Debugging tip: use the below line and comment out the mp.Pool loop
        # block to remain in single process
        # self.doc_processor_fn(docs[0])
        
        with mp.Pool(processes=self.num_processes) as pool:
            results = pool.map(self.doc_processor_fn, docs)
        
        self.cleanup()

@click.command()
@click.option('--s3-url', default="s3://utic-dev-tech-fixtures/small-pdf-set/",
              help="Prefix of s3 objects (files) to download. E.g. s3://bucket1/path/. This value may also be a single file.")
@click.option('--re-download/--no-re-download', default=False,
              help="Re-download files from s3 even if they are already present in --download-dir.")
@click.option('--download-dir',
              help="Where s3 files are downloaded to, defaults to tmp-ingest-<6 random chars>." )
@click.option('--preserve-downloads', is_flag=True, default=False,
              help="Preserve downloaded s3 files. Otherwise each file is removed after being processed successfully."  )
@click.option('--structured-output-dir', default="structured-output",
              help="Where to place structured output .json files.")
@click.option('--reprocess', is_flag=True, default=False,
              help="Reprocess a downloaded file from s3 even if the relevant structured output .json file in --structured-output-dir already exists.")
@click.option('--num-processes', default=2, show_default=True,
              help="Number of parallel processes to process docs in.")
@click.option('--anonymous', is_flag=True, default=False,
              help="Connect to s3 without local AWS credentials.")
@click.option('-v', '--verbose', is_flag=True, default=False)
def main(s3_url, re_download, download_dir, preserve_downloads, structured_output_dir,
         reprocess, num_processes, anonymous, verbose):
    if not preserve_downloads and download_dir:
        print("Warning: not preserving downloaded s3 files but --download_dir is specified")
    if not download_dir:
        download_dir = "tmp-ingest-" + "".join(
            random.choice(string.ascii_letters) for i in range(6)
        )
    doc_connector = S3Connector(
        config=SimpleS3Config(
            download_dir=download_dir,
            s3_url=s3_url,
            output_dir=structured_output_dir,
            # set to False to use your AWS creds (not needed for this public s3 url)
            anonymous=anonymous,
            re_download=re_download,
            preserve_downloads=preserve_downloads,
            verbose=verbose,
        ),
    )
    MainProcess(doc_connector=doc_connector,
                doc_processor_fn=process_document,
                num_processes=num_processes,
                reprocess=reprocess,
                ).run()

        
if __name__ == '__main__':
    main()