import json
import zipfile
import pandas as pd
from huggingface_hub import hf_hub_download, list_repo_files
from llama_index.core import Document
from llama_index.core.text_splitter import SentenceSplitter
from my_logging import log_message

# Configuration
CHUNK_SIZE = 1500
CHUNK_OVERLAP = 128

def chunk_text_documents(documents):
    text_splitter = SentenceSplitter(
        chunk_size=CHUNK_SIZE,
        chunk_overlap=CHUNK_OVERLAP
    )
    
    chunked = []
    for doc in documents:
        chunks = text_splitter.get_nodes_from_documents([doc])
        for i, chunk in enumerate(chunks):
            chunk.metadata.update({
                'chunk_id': i,
                'total_chunks': len(chunks),
                'chunk_size': len(chunk.text)  # Add chunk size
            })
            chunked.append(chunk)
    
    # Log statistics
    if chunked:
        avg_size = sum(len(c.text) for c in chunked) / len(chunked)
        min_size = min(len(c.text) for c in chunked)
        max_size = max(len(c.text) for c in chunked)
        log_message(f"✓ Text: {len(documents)} docs → {len(chunked)} chunks")
        log_message(f"  Size stats: avg={avg_size:.0f}, min={min_size}, max={max_size} chars")
    
    return chunked


def chunk_table_by_rows(table_data, doc_id, rows_per_chunk=10, max_chars=2000):
    """
    Chunk tables by rows with fallback to character limit.
    Keeps 3-4 rows together, but splits individual rows if they're too large.
    """
    headers = table_data.get('headers', [])
    rows = table_data.get('data', [])
    table_num = str(table_data.get('table_number', 'unknown')).strip()
    table_title = table_data.get('table_title', '')
    section = table_data.get('section', '')
    
    # Section-aware identifier (keep your existing logic)
    import re
    if 'приложени' in section.lower():
        appendix_match = re.search(r'приложени[еия]\s*(\d+|[а-яА-Я])', section.lower())
        if appendix_match:
            appendix_num = appendix_match.group(1).upper()
            table_identifier = f"{table_num} Приложение {appendix_num}"
        else:
            table_identifier = table_num
    else:
        table_identifier = table_num
    
    if not rows:
        return []
    
    log_message(f"  📊 Processing: {doc_id} - {table_identifier} ({len(rows)} rows)")
    
    # Build base header (compact version)
    base_header = f"ДОКУМЕНТ: {doc_id} | ТАБЛИЦА: {table_identifier}\n"
    if table_title:
        base_header += f"НАЗВАНИЕ: {table_title}\n"
    base_header += f"{'='*60}\n"
    
    if headers:
        header_str = ' | '.join(str(h)[:30] for h in headers)  # Truncate long headers
        base_header += f"ЗАГОЛОВКИ: {header_str}\n\n"
    
    # Calculate available space
    base_size = len(base_header)
    footer_size = 100
    available_space = max_chars - base_size - footer_size
    
    chunks = []
    current_batch = []
    current_size = 0
    chunk_num = 0
    
    for i, row in enumerate(rows):
        row_text = format_single_row(row, i + 1)
        row_size = len(row_text)
        
        # Case 1: Single row exceeds max - split it internally
        if row_size > available_space:
            # Flush current batch first
            if current_batch:
                chunks.append(_create_chunk(
                    base_header, current_batch, table_identifier, 
                    doc_id, table_num, table_title, section, 
                    len(rows), chunk_num, False
                ))
                chunk_num += 1
                current_batch = []
                current_size = 0
            log_message(f"    ⚠ Row {i+1} too large ({row_size} chars), splitting...")
            # Split the large row
            split_chunks = _split_large_row(
                row, i + 1, base_header, available_space,
                table_identifier, doc_id, table_num, table_title, 
                section, len(rows), chunk_num
            )
            chunks.extend(split_chunks)
            log_message(f"      → Created {len(split_chunks)} chunks from row {i+1}")
            chunk_num += len(split_chunks)
            continue
        
        # Case 2: Adding this row would exceed limit - flush current batch
        if current_size + row_size > available_space and current_batch:
            chunks.append(_create_chunk(
                base_header, current_batch, table_identifier,
                doc_id, table_num, table_title, section,
                len(rows), chunk_num, False
            ))
            chunk_num += 1
            current_batch = []
            current_size = 0
        
        # Case 3: Add row to current batch
        current_batch.append({'row': row, 'idx': i + 1, 'text': row_text})
        log_message(f"    + Row {i+1} ({row_size} chars) added to chunk {chunk_num}")
        current_size += row_size
        
        # Flush if we hit target row count
        if len(current_batch) >= rows_per_chunk:
            chunks.append(_create_chunk(
                base_header, current_batch, table_identifier,
                doc_id, table_num, table_title, section,
                len(rows), chunk_num, False
            ))
            chunk_num += 1
            current_batch = []
            current_size = 0
    
    # Flush remaining rows
    if current_batch:
        chunks.append(_create_chunk(
            base_header, current_batch, table_identifier,
            doc_id, table_num, table_title, section,
            len(rows), chunk_num, len(chunks) == 0
        ))
    
    log_message(f"    Created {len(chunks)} chunks from {len(rows)} rows")
    return chunks


def _create_chunk(base_header, batch, table_identifier, doc_id, 
                  table_num, table_title, section, total_rows, 
                  chunk_num, is_complete):
    """Helper to create a chunk with full metadata"""
    content = base_header + "ДАННЫЕ:\n"
    
    for item in batch:
        content += item['text']
    
    row_start = batch[0]['idx']
    row_end = batch[-1]['idx']
    
    # Add footer with row info
    if not is_complete:
        content += f"\n[Строки {row_start}-{row_end} из {total_rows}]"
    
    # EMBED ALL METADATA IN TEXT for better retrieval
    content += f"\n\n--- МЕТАДАННЫЕ ---\n"
    content += f"Документ: {doc_id}\n"
    content += f"Таблица: {table_identifier}\n"
    content += f"Название таблицы: {table_title}\n"
    content += f"Раздел: {section}\n"
    content += f"Строки: {row_start}-{row_end} из {total_rows}\n"
    
    metadata = {
        'type': 'table',
        'document_id': doc_id,
        'table_number': table_num,
        'table_identifier': table_identifier,
        'table_title': table_title,
        'section': section,
        'chunk_id': chunk_num,
        'row_start': row_start - 1,
        'row_end': row_end,
        'total_rows': total_rows,
        'chunk_size': len(content),
        'is_complete_table': is_complete,
        'rows_in_chunk': len(batch)
    }
    
    return Document(text=content, metadata=metadata)


def _split_large_row(row, row_idx, base_header, max_size, 
                     table_identifier, doc_id, table_num, 
                     table_title, section, total_rows, base_chunk_num):
    """Split a single large row into multiple chunks"""
    if isinstance(row, dict):
        items = list(row.items())
    else:
        items = [(f"col_{i}", v) for i, v in enumerate(row)]
    
    chunks = []
    current_items = []
    current_size = 0
    part_num = 0
    
    for key, value in items:
        item_text = f"{key}: {value}\n"
        item_size = len(item_text)
        
        if current_size + item_size > max_size and current_items:
            # Create chunk for current items
            content = base_header + "ДАННЫЕ:\n"
            content += f"Строка {row_idx} (часть {part_num + 1}):\n"
            content += "".join(current_items)
            content += f"\n[Строка {row_idx} из {total_rows} - продолжается]"
            
            chunks.append(_create_chunk_from_text(
                content, doc_id, table_num, table_identifier,
                table_title, section, row_idx, row_idx,
                total_rows, base_chunk_num + part_num
            ))
            
            part_num += 1
            current_items = []
            current_size = 0
        
        current_items.append(item_text)
        current_size += item_size
    
    # Flush remaining
    if current_items:
        content = base_header + "ДАННЫЕ:\n"
        content += f"Строка {row_idx} (часть {part_num + 1}):\n"
        content += "".join(current_items)
        
        chunks.append(_create_chunk_from_text(
            content, doc_id, table_num, table_identifier,
            table_title, section, row_idx, row_idx,
            total_rows, base_chunk_num + part_num
        ))
    
    return chunks


def _create_chunk_from_text(content, doc_id, table_num, table_identifier,
                            table_title, section, row_start, row_end,
                            total_rows, chunk_num):
    """Helper for creating chunk from pre-built text"""
    metadata = {
        'type': 'table',
        'document_id': doc_id,
        'table_number': table_num,
        'table_identifier': table_identifier,
        'table_title': table_title,
        'section': section,
        'chunk_id': chunk_num,
        'row_start': row_start - 1,
        'row_end': row_end,
        'total_rows': total_rows,
        'chunk_size': len(content),
        'is_complete_table': False
    }
    
    return Document(text=content, metadata=metadata)


def format_single_row(row, idx):
    """Format a single row"""
    if isinstance(row, dict):
        parts = [f"{k}: {v}" for k, v in row.items() 
                if v and str(v).strip() and str(v).lower() not in ['nan', 'none', '']]
        if parts:
            return f"{idx}. {' | '.join(parts)}\n"
    elif isinstance(row, list):
        parts = [str(v) for v in row if v and str(v).strip() and str(v).lower() not in ['nan', 'none', '']]
        if parts:
            return f"{idx}. {' | '.join(parts)}\n"
    return ""



def load_table_documents(repo_id, hf_token, table_dir):
    log_message("Loading tables...")
    
    files = list_repo_files(repo_id=repo_id, repo_type="dataset", token=hf_token)
    table_files = [f for f in files if f.startswith(table_dir) and f.endswith('.json')]
    
    all_chunks = []
    for file_path in table_files:
        try:
            local_path = hf_hub_download(
                repo_id=repo_id,
                filename=file_path,
                repo_type="dataset",
                token=hf_token
            )
            
            with open(local_path, 'r', encoding='utf-8') as f:
                data = json.load(f)
            
            file_doc_id = data.get('document_id', data.get('document', 'unknown'))
            
            for sheet in data.get('sheets', []):
                sheet_doc_id = sheet.get('document_id', sheet.get('document', file_doc_id))
                
                # USE NEW ADAPTIVE CHUNKING
                chunks = chunk_table_by_rows(sheet, sheet_doc_id, max_chars=3072)
                all_chunks.extend(chunks)
                log_message(f"  📄 {sheet_doc_id}: {len(chunks)} chunks")
        except Exception as e:
            log_message(f"Error loading {file_path}: {e}")
    
    log_message(f"✓ Loaded {len(all_chunks)} table chunks")
    return all_chunks


def load_json_documents(repo_id, hf_token, json_dir):
    import zipfile
    import tempfile
    import os
    
    log_message("Loading JSON documents...")
    
    files = list_repo_files(repo_id=repo_id, repo_type="dataset", token=hf_token)
    json_files = [f for f in files if f.startswith(json_dir) and f.endswith('.json')]
    zip_files = [f for f in files if f.startswith(json_dir) and f.endswith('.zip')]
    
    log_message(f"Found {len(json_files)} JSON files and {len(zip_files)} ZIP files")
    
    documents = []
    stats = {'success': 0, 'failed': 0, 'empty': 0}
    
    for file_path in json_files:
        try:
            log_message(f"  Loading: {file_path}")
            local_path = hf_hub_download(
                repo_id=repo_id,
                filename=file_path,
                repo_type="dataset",
                token=hf_token
            )
            
            docs = extract_sections_from_json(local_path)
            if docs:
                documents.extend(docs)
                stats['success'] += 1
                log_message(f"    ✓ Extracted {len(docs)} sections")
            else:
                stats['empty'] += 1
                log_message(f"    ⚠ No sections found")
            
        except Exception as e:
            stats['failed'] += 1
            log_message(f"    ✗ Error: {e}")
    
    for zip_path in zip_files:
        try:
            log_message(f"  Processing ZIP: {zip_path}")
            local_zip = hf_hub_download(
                repo_id=repo_id,
                filename=zip_path,
                repo_type="dataset",
                token=hf_token
            )
            
            with zipfile.ZipFile(local_zip, 'r') as zf:
                json_files_in_zip = [f for f in zf.namelist() 
                                    if f.endswith('.json') 
                                    and not f.startswith('__MACOSX')
                                    and not f.startswith('.')
                                    and not '._' in f]
                
                log_message(f"    Found {len(json_files_in_zip)} JSON files in ZIP")
                
                for json_file in json_files_in_zip:
                    try:
                        file_content = zf.read(json_file)
                        
                        # Skip if file is too small
                        if len(file_content) < 10:
                            log_message(f"      ✗ Skipping: {json_file} (file too small)")
                            stats['failed'] += 1
                            continue
                        
                        # Try UTF-8 first (most common)
                        try:
                            text_content = file_content.decode('utf-8')
                        except UnicodeDecodeError:
                            try:
                                text_content = file_content.decode('utf-8-sig')
                            except UnicodeDecodeError:
                                try:
                                    # Try UTF-16 (the issue you're seeing)
                                    text_content = file_content.decode('utf-16')
                                except UnicodeDecodeError:
                                    try:
                                        text_content = file_content.decode('windows-1251')
                                    except UnicodeDecodeError:
                                        log_message(f"      ✗ Skipping: {json_file} (encoding failed)")
                                        stats['failed'] += 1
                                        continue
                        
                        # Validate JSON structure
                        if not text_content.strip().startswith('{') and not text_content.strip().startswith('['):
                            log_message(f"      ✗ Skipping: {json_file} (not valid JSON)")
                            stats['failed'] += 1
                            continue
                        
                        with tempfile.NamedTemporaryFile(mode='w', delete=False, 
                                                        suffix='.json', encoding='utf-8') as tmp:
                            tmp.write(text_content)
                            tmp_path = tmp.name
                        
                        docs = extract_sections_from_json(tmp_path)
                        if docs:
                            documents.extend(docs)
                            stats['success'] += 1
                            log_message(f"      ✓ {json_file}: {len(docs)} sections")
                        else:
                            stats['empty'] += 1
                            log_message(f"      ⚠ {json_file}: No sections")
                        
                        os.unlink(tmp_path)
                        
                    except json.JSONDecodeError as e:
                        stats['failed'] += 1
                        log_message(f"      ✗ {json_file}: Invalid JSON")
                    except Exception as e:
                        stats['failed'] += 1
                        log_message(f"      ✗ {json_file}: {str(e)[:100]}")
                        
        except Exception as e:
            log_message(f"    ✗ Error with ZIP: {e}")
    
    log_message(f"="*60)
    log_message(f"JSON Loading Stats:")
    log_message(f"  Success: {stats['success']}")
    log_message(f"  Empty: {stats['empty']}")
    log_message(f"  Failed: {stats['failed']}")
    log_message(f"  Total sections: {len(documents)}")
    log_message(f"="*60)
    
    return documents

def extract_sections_from_json(json_path):
    """Extract sections from a single JSON file"""
    documents = []
    
    try:
        with open(json_path, 'r', encoding='utf-8') as f:
            data = json.load(f)
        
        doc_id = data.get('document_metadata', {}).get('document_id', 'unknown')
        
        # Extract all section levels
        for section in data.get('sections', []):
            if section.get('section_text', '').strip():
                documents.append(Document(
                    text=section['section_text'],
                    metadata={
                        'type': 'text',
                        'document_id': doc_id,
                        'section_id': section.get('section_id', '')
                    }
                ))
            
            # Subsections
            for subsection in section.get('subsections', []):
                if subsection.get('subsection_text', '').strip():
                    documents.append(Document(
                        text=subsection['subsection_text'],
                        metadata={
                            'type': 'text',
                            'document_id': doc_id,
                            'section_id': subsection.get('subsection_id', '')
                        }
                    ))
                
                # Sub-subsections
                for sub_sub in subsection.get('sub_subsections', []):
                    if sub_sub.get('sub_subsection_text', '').strip():
                        documents.append(Document(
                            text=sub_sub['sub_subsection_text'],
                            metadata={
                                'type': 'text',
                                'document_id': doc_id,
                                'section_id': sub_sub.get('sub_subsection_id', '')
                            }
                        ))
    
    except Exception as e:
        log_message(f"Error extracting from {json_path}: {e}")
    
    return documents


def load_image_data(repo_id, hf_token, image_data_dir):
    log_message("Начинаю загрузку данных изображений")
    
    image_files = []
    try:
        files = list_repo_files(repo_id=repo_id, repo_type="dataset", token=hf_token)
        for file in files:
            if file.startswith(image_data_dir) and file.endswith('.csv'):
                image_files.append(file)
        
        log_message(f"Найдено {len(image_files)} CSV файлов с изображениями")
        
        image_documents = []
        for file_path in image_files:
            try:
                log_message(f"Обрабатываю файл изображений: {file_path}")
                local_path = hf_hub_download(
                    repo_id=repo_id,
                    filename=file_path,
                    local_dir='',
                    repo_type="dataset",
                    token=hf_token
                )
                
                df = pd.read_csv(local_path)
                log_message(f"Загружено {len(df)} записей изображений из файла {file_path}")
                
                # Обработка с правильными названиями колонок
                for _, row in df.iterrows():
                    section_value = row.get('Раздел документа', 'Неизвестно')
                    
                    content = f"Изображение: {row.get('№ Изображения', 'Неизвестно')}\n"
                    content += f"Название: {row.get('Название изображения', 'Неизвестно')}\n"
                    content += f"Описание: {row.get('Описание изображение', 'Неизвестно')}\n"  # Опечатка в названии колонки
                    content += f"Документ: {row.get('Обозначение документа', 'Неизвестно')}\n"
                    content += f"Раздел: {section_value}\n"
                    content += f"Файл: {row.get('Файл изображения', 'Неизвестно')}\n"
                    
                    doc = Document(
                        text=content,
                        metadata={
                            "type": "image",
                            "image_number": str(row.get('№ Изображения', 'unknown')),
                            "image_title": str(row.get('Название изображения', 'unknown')),
                            "image_description": str(row.get('Описание изображение', 'unknown')),
                            "document_id": str(row.get('Обозначение документа', 'unknown')),
                            "file_path": str(row.get('Файл изображения', 'unknown')),
                            "section": str(section_value),
                            "section_id": str(section_value)
                        }
                    )
                    image_documents.append(doc)
                        
            except Exception as e:
                log_message(f"Ошибка обработки файла {file_path}: {str(e)}")
                continue
        
        log_message(f"Создано {len(image_documents)} документов из изображений")
        return image_documents
        
    except Exception as e:
        log_message(f"Ошибка загрузки данных изображений: {str(e)}")
        return []

def load_all_documents(repo_id, hf_token, json_dir, table_dir, image_dir):
    """Main loader - combines all document types"""
    log_message("="*60)
    log_message("STARTING DOCUMENT LOADING")
    log_message("="*60)
    
    # Load text sections
    text_docs = load_json_documents(repo_id, hf_token, json_dir)
    text_chunks = chunk_text_documents(text_docs)
    
    # Load tables (already chunked)
    table_chunks = load_table_documents(repo_id, hf_token, table_dir)
    
    # Load images (no chunking needed)
    image_docs = load_image_data(repo_id, hf_token, image_dir)
    
    all_docs = text_chunks + table_chunks + image_docs
    
    log_message("="*60)
    log_message(f"TOTAL DOCUMENTS: {len(all_docs)}")
    log_message(f"  Text chunks: {len(text_chunks)}")
    log_message(f"  Table chunks: {len(table_chunks)}")
    log_message(f"  Images: {len(image_docs)}")
    log_message("="*60)
    
    return all_docs