import json
import logging

def process_json_files(start, end):
    """
    Processes JSON files containing Tanach text and returns a dictionary
    mapping book IDs to their data.

    Args:
      start: The starting book ID (inclusive).
      end: The ending book ID (inclusive).

    Returns:
      A dictionary where keys are book IDs and values are dictionaries
      containing 'title' and 'text' fields.
    """
    base_path = "texts"
    results = {}

    for i in range(start, end + 1):
        file_name = f"{base_path}/{i:02}.json"
        try:
            with open(file_name, 'r', encoding='utf-8') as file:
                data = json.load(file)
                if data:
                    results[i] = {"title": data.get("title", "No title"), "text": data.get("text", [])}
        except FileNotFoundError:
            logging.warning(f"File {file_name} not found.")
        except json.JSONDecodeError as e:
            logging.warning(f"File {file_name} could not be read as JSON: {e}")
        except KeyError as e:
            logging.warning(f"Expected key 'text' is missing in {file_name}: {e}")

    return results

def flatten_text_with_line_breaks(text):
    """
    Flattens nested lists while preserving line breaks.
    """
    flattened_text = []
    for item in text:
        if isinstance(item, list):
            flattened_text.extend(flatten_text_with_line_breaks(item))
        elif isinstance(item, str):
            flattened_text.append(item)
        else:
            flattened_text.append(str(item))
    return flattened_text

def calculate_tanach_statistics(tanach_data):
    """
    Calculates statistics for the Tanach corpus.
    """
    book_stats = {}
    total_chapters = 0
    total_verses = 0
    total_words = 0

    for book_id in tanach_data:
        book_title = tanach_data[book_id]["title"]
        chapters = tanach_data[book_id]["text"]
        book_chapters = len(chapters)
        book_verses = 0
        book_words = 0

        for chapter in chapters:
            flattened_chapter = flatten_text_with_line_breaks(chapter)
            book_verses += len(flattened_chapter)
            book_words += len(flattened_chapter)

        total_chapters += book_chapters
        total_verses += book_verses
        total_words += book_words

        book_stats[book_id] = {
            "title": book_title,
            "chapters": book_chapters,
            "verses": book_verses,
            "words": book_words
        }

    average_words_per_verse = total_words / total_verses if total_verses > 0 else 0

    corpus_stats = {
        "total_books": len(tanach_data),
        "total_chapters": total_chapters,
        "total_verses": total_verses,
        "total_words": total_words,
        "average_words_per_verse": average_words_per_verse,
        "book_stats": book_stats
    }

    return corpus_stats

def build_word_index(tanach_data):
    """
    Builds a word index for efficient lookup.
    """
    word_index = {}
    word_count = 0
    for book_id in tanach_data:
        for chapter_index, chapter in enumerate(tanach_data[book_id]["text"]):
            flattened_chapter = flatten_text_with_line_breaks(chapter)
            for verse_index, word in enumerate(flattened_chapter):
                word_index[word_count] = {
                    "book_id": book_id,
                    "chapter_id": chapter_index,
                    "verse_id": verse_index + 1,
                }
                word_count += 1
    return word_index