import os
import webvtt
import re
from datetime import datetime
from llama_index import Document


class VTTTranscriptLoader:
    """
    vtt file ingestion and cleaning. This was done because vtt files
    are not recognized by llamaindex. The output should mirror that of
    any document loader from llamaindex or langchain.
    """

    def __init__(self, file_path):
        self.fp = file_path
        self.data = None

    def open_vtt(self, file_path, plaintext=True):
        """Read VTT file."""
        if plaintext:
            with open(file_path, "r") as f:
                data = f.readlines()
        else:
            data = webvtt.read(file_path)
        return data

    def extract_speaker_name(self, text):
        """Extracts the speaker name from a VTT caption."""
        match = re.search(r"<v (.*?)>", text)
        if match:
            return match.group(1)
        else:
            return None

    def extract_speaker_words(self, captions):
        """Extracts the speaker text from a VTT caption."""
        return [caption.text for caption in captions]

    def merge_speaker_words(self, words, speakers, split=True):
        """Joins speaker names with their words."""
        # Extract speaker names
        speaker_list = [self.extract_speaker_name(line) for line in speakers if self.extract_speaker_name(line)]
        # Extract words
        words_list = self.extract_speaker_words(words)
        # Combine speaker names and words
        combined_list = list(zip(speaker_list, words_list))
        # Return the combined list as a single string if split is False
        if not split:
            combined_list = '\n'.join([f"{name}: '{text}'" for name, text in combined_list])
        return combined_list, speaker_list

    def get_metadata(self, speaker_list, file_path):
        """Generates metadata for the transcript."""
        # Meeting length
        time_format = "%H:%M:%S.%f"
        sess = self.open_vtt(file_path, plaintext=False)

        dt1 = datetime.strptime(sess[0].start, time_format)
        dt2 = datetime.strptime(sess[-1].end, time_format)

        minutes = (dt2 - dt1).seconds / 60
        # Meeting date
        match = re.search(r"\d{4}[-_]\d{2}[-_]\d{2}", file_path)
        if match:
            date_str = match.group().replace('_', '-')
            date_obj = datetime.strptime(date_str, "%Y-%m-%d").date()
        else:
            date_obj = None

        # Pull dictionary here
        output = {
            'title': file_path,
            'duration': minutes,
            'meeting_date': date_obj.strftime("%Y-%m-%d"),
            'speakers': list(set(speaker_list)),
        }

        return output

    def manual_document(self, output, metadata):
        """Create document manually"""
        document = Document(text=output)
        document.metadata = metadata
        return document

    def process_file(self, file_path):
        """Processes a single VTT file and returns the combined speaker names and words."""
        # Get words as webvtt captions
        words = self.open_vtt(file_path, plaintext=False)
        # Get speaker lines as plaintext
        speaker = self.open_vtt(file_path, plaintext=True)
        # Combine speaker names and words
        output, speaker_list = self.merge_speaker_words(words, speaker, split=False)
        # Get session data as dictionary
        metadata = self.get_metadata(speaker_list, file_path)

        return self.manual_document(output, metadata)

    def load(self):
        """Processes all VTT files in the directory or the single file and returns a list of results."""
        results = []
        if os.path.isdir(self.fp):
            for root, _, files in os.walk(self.fp):
                for file in files:
                    if file.endswith('.vtt'):
                        file_path = os.path.join(root, file)
                        transcript = self.process_file(file_path)
                        results.append(transcript)
        else:
            transcript = self.process_file(self.fp)
            results.append(transcript)
        return results