"""
Presentation Layer - API Endpoints
"""
import time
from datetime import datetime
from typing import List
from uuid import uuid4

from fastapi import APIRouter, Depends, File, Form, HTTPException, UploadFile, status
from sqlalchemy.ext.asyncio import AsyncSession

from app.application.dto import DocumentUploadDTO, QueryDTO
from app.application.services import ChunkingService
from app.application.use_cases.document_indexing import DocumentIndexingUseCase
from app.application.use_cases.query_processing import QueryProcessingUseCase
from app.core.config import get_settings
from app.core.logging import get_logger, set_correlation_id
from app.core.metrics import (
    active_requests,
    http_request_duration_seconds,
    http_requests_total,
    queries_total,
)
from app.infrastructure.cache.redis_cache import RedisCache
from app.infrastructure.external.embedder import SentenceTransformerEmbedder
from app.infrastructure.external.gemini_llm import GeminiLLM
from app.infrastructure.external.prompt_builder import DefaultPromptBuilder
from app.infrastructure.external.qdrant_retriever import QdrantRetriever
from app.infrastructure.repositories.postgres_repository import (
    PostgresChunkRepository,
    PostgresDocumentRepository,
)
from app.presentation.api.v1.schemas import (
    DocumentResponse,
    HealthResponse,
    QueryRequest,
    QueryResponse,
    SourceSchema,
)

router = APIRouter(prefix="/api/v1", tags=["api"])
logger = get_logger(__name__)
settings = get_settings()


# Dependency injection (simplified - in production use proper DI container)
async def get_query_use_case() -> QueryProcessingUseCase:
    """Get query processing use case"""
    # Initialize services
    embedder = SentenceTransformerEmbedder(settings.embedding_model)
    retriever = QdrantRetriever(
        url=settings.qdrant_url,
        collection_name=settings.qdrant_collection_name,
        vector_size=settings.qdrant_vector_size,
        api_key=settings.qdrant_api_key if settings.qdrant_api_key else None,
    )
    llm = GeminiLLM(api_key=settings.gemini_api_key, model_name=settings.gemini_model)
    prompt_builder = DefaultPromptBuilder()
    cache = RedisCache(redis_url=settings.redis_url)

    # For now, using a simple reranker (in production use cross-encoder)
    from app.infrastructure.external.simple_reranker import SimpleReranker

    reranker = SimpleReranker()

    return QueryProcessingUseCase(
        retriever=retriever,
        reranker=reranker,
        llm=llm,
        prompt_builder=prompt_builder,
        cache=cache,
    )


@router.post("/query", response_model=QueryResponse, status_code=status.HTTP_200_OK)
async def process_query(
    request: QueryRequest,
    use_case: QueryProcessingUseCase = Depends(get_query_use_case),
) -> QueryResponse:
    """Process user query through RAG pipeline"""
    start_time = time.time()
    correlation_id = str(uuid4())
    set_correlation_id(correlation_id)

    active_requests.inc()

    try:
        logger.info("processing_query", query=request.query_text, department=request.department)

        # Convert to DTO
        query_dto = QueryDTO(
            query_text=request.query_text,
            department=request.department,
            user_id=request.user_id,
            session_id=request.session_id,
            top_k=request.top_k,
            temperature=request.temperature,
            max_tokens=request.max_tokens,
            filters=request.filters,
        )

        # Execute use case
        response_dto = await use_case.execute(query_dto)

        # Convert to response schema
        response = QueryResponse(
            query_id=response_dto.query_id,
            answer=response_dto.answer,
            sources=[
                SourceSchema(
                    title=src.title,
                    content=src.content,
                    relevance_score=src.relevance_score,
                    document_id=src.document_id,
                    chunk_index=src.chunk_index,
                    metadata=src.metadata,
                )
                for src in response_dto.sources
            ],
            confidence=response_dto.confidence,
            processing_time_ms=response_dto.processing_time_ms,
            tokens_used=response_dto.tokens_used,
            model=response_dto.model,
        )

        # Metrics
        duration = time.time() - start_time
        http_requests_total.labels(method="POST", endpoint="/api/v1/query", status="200").inc()
        http_request_duration_seconds.labels(method="POST", endpoint="/api/v1/query").observe(
            duration
        )
        queries_total.labels(department=request.department, status="success").inc()

        logger.info("query_processed", query_id=response.query_id, duration_ms=int(duration * 1000))

        return response

    except Exception as e:
        logger.error("query_processing_error", error=str(e), exc_info=True)
        http_requests_total.labels(method="POST", endpoint="/api/v1/query", status="500").inc()
        queries_total.labels(department=request.department, status="error").inc()
        raise HTTPException(status_code=500, detail=f"Query processing failed: {str(e)}")

    finally:
        active_requests.dec()


@router.get("/health", response_model=HealthResponse)
async def health_check() -> HealthResponse:
    """Health check endpoint"""
    return HealthResponse(
        status="healthy",
        version=settings.app_version,
        timestamp=datetime.utcnow(),
        services={
            "database": "unknown",  # TODO: Add actual health checks
            "redis": "unknown",
            "qdrant": "unknown",
        },
    )


@router.get("/metrics")
async def metrics():
    """Prometheus metrics endpoint"""
    from prometheus_client import CONTENT_TYPE_LATEST, generate_latest

    return generate_latest()