"""
Example: RAG Pipeline

Demonstrates:
1. Indexing documents into vector store
2. Semantic search
3. Question answering with citations
"""

from pathlib import Path
from loguru import logger

# Import RAG components
from src.rag import (
    VectorStoreConfig,
    EmbeddingConfig,
    RetrieverConfig,
    GeneratorConfig,
    get_document_indexer,
    get_document_retriever,
    get_grounded_generator,
)


def example_indexing():
    """Index documents into vector store."""
    print("=" * 50)
    print("Document Indexing")
    print("=" * 50)

    # Get indexer
    indexer = get_document_indexer()

    # Index a document
    sample_doc = Path("./data/sample.pdf")

    if not sample_doc.exists():
        print(f"Sample document not found: {sample_doc}")
        print("Create a sample PDF at ./data/sample.pdf")
        return False

    # Index
    result = indexer.index_document(sample_doc)

    if result.success:
        print(f"\nIndexed: {result.source_path}")
        print(f"  Document ID: {result.document_id}")
        print(f"  Chunks indexed: {result.num_chunks_indexed}")
        print(f"  Chunks skipped: {result.num_chunks_skipped}")
    else:
        print(f"Indexing failed: {result.error}")
        return False

    # Show stats
    stats = indexer.get_index_stats()
    print(f"\nIndex Stats:")
    print(f"  Total chunks: {stats['total_chunks']}")
    print(f"  Documents: {stats['num_documents']}")
    print(f"  Embedding model: {stats['embedding_model']}")

    return True


def example_search():
    """Search indexed documents."""
    print("\n" + "=" * 50)
    print("Semantic Search")
    print("=" * 50)

    # Get retriever
    retriever = get_document_retriever()

    # Search queries
    queries = [
        "What is the main topic?",
        "key findings",
        "conclusions and recommendations",
    ]

    for query in queries:
        print(f"\nQuery: '{query}'")

        chunks = retriever.retrieve(query, top_k=3)

        if not chunks:
            print("  No results found")
            continue

        for i, chunk in enumerate(chunks, 1):
            print(f"\n  [{i}] Similarity: {chunk.similarity:.3f}")
            if chunk.page is not None:
                print(f"      Page: {chunk.page + 1}")
            print(f"      Text: {chunk.text[:150]}...")


def example_question_answering():
    """Answer questions using RAG."""
    print("\n" + "=" * 50)
    print("Question Answering with Citations")
    print("=" * 50)

    # Get generator
    generator = get_grounded_generator()

    # Questions
    questions = [
        "What is the main purpose of this document?",
        "What are the key findings?",
        "What recommendations are made?",
    ]

    for question in questions:
        print(f"\nQuestion: {question}")
        print("-" * 40)

        result = generator.answer_question(question, top_k=5)

        print(f"\nAnswer: {result.answer}")
        print(f"\nConfidence: {result.confidence:.2f}")

        if result.abstained:
            print(f"Note: {result.abstain_reason}")

        if result.citations:
            print(f"\nCitations ({len(result.citations)}):")
            for citation in result.citations:
                page = f"Page {citation.page + 1}" if citation.page is not None else ""
                print(f"  [{citation.index}] {page}: {citation.text_snippet[:60]}...")


def example_filtered_search():
    """Search with metadata filters."""
    print("\n" + "=" * 50)
    print("Filtered Search")
    print("=" * 50)

    retriever = get_document_retriever()

    # Search only in tables
    print("\nSearching for tables only...")
    table_chunks = retriever.retrieve_tables("data values", top_k=3)

    if table_chunks:
        print(f"Found {len(table_chunks)} table chunks:")
        for chunk in table_chunks:
            print(f"  - Page {chunk.page + 1}: {chunk.text[:100]}...")
    else:
        print("No table chunks found")

    # Search specific page range
    print("\nSearching pages 1-3...")
    page_chunks = retriever.retrieve_by_page(
        "introduction",
        page_range=(0, 2),
        top_k=3,
    )

    if page_chunks:
        print(f"Found {len(page_chunks)} chunks in pages 1-3:")
        for chunk in page_chunks:
            print(f"  - Page {chunk.page + 1}: {chunk.text[:100]}...")
    else:
        print("No chunks found in specified pages")


def example_full_pipeline():
    """Complete RAG pipeline demo."""
    print("\n" + "=" * 50)
    print("Full RAG Pipeline Demo")
    print("=" * 50)

    # Step 1: Index
    print("\n[Step 1] Indexing documents...")
    if not example_indexing():
        return

    # Step 2: Search
    print("\n[Step 2] Testing search...")
    example_search()

    # Step 3: Q&A
    print("\n[Step 3] Question answering...")
    example_question_answering()

    print("\n" + "=" * 50)
    print("Pipeline demo complete!")
    print("=" * 50)


if __name__ == "__main__":
    # Run full pipeline
    example_full_pipeline()