from functools import lru_cache
import logging
from pathlib import Path

from pydantic_settings import BaseSettings

logger = logging.getLogger(__name__)


class Settings(BaseSettings):
    # LLM access (OpenRouter / vLLM)
    llm_base_url: str = "https://openrouter.ai/api/v1"
    llm_api_key: str = ""
    llm_model_name: str = "qwen/qwen3.5-35b-a3b"
    llm_enable_thinking: bool = False
    vllm_engine: bool = False

    # Deepseek API (decompose step only, Package 6)
    dp_base_url: str = "https://api.deepseek.com"
    dp_api_key: str = ""
    dp_model_name: str = "deepseek-v4-flash"

    # Embeddings
    embedding_model: str = "qwen/qwen3-embedding-4b"
    embedding_base_url: str = "https://openrouter.ai/api/v1"
    embedding_api_key: str = ""

    # ChromaDB
    chroma_db_path: str = "./chroma_db"

    # Chunk PDF storage (extracted PDF pages)
    document_chunk_path: str = "./document_chunk"

    # SQLite databases (Package 3)
    prompts_db_path: str = "./data/prompts.db"
    history_db_path: str = "./data/history.db"

    # App configuration moved to settings for easier testing/configuration
    # Cross-origin settings and chunking parameters (Phase 1 plan)
    cors_origins: list[str] = ["http://localhost:5173", "http://localhost:3000"]
    chunk_size: int = 1000
    chunk_overlap: int = 200
    retrieval_n_results: int = 10
    relevance_threshold: float = 7.0
    llm_timeout: float = 60.0

    # Q&A-pair chunking strategy (Package 8)
    default_chunking_strategy: str = "token"
    qa_vision_enabled: bool = True
    qa_max_chunk_tokens: int = 3000
    qa_structure_model: str = ""
    qa_include_internal_refs: bool = True
    qa_cache_vision_results: bool = True

    # ASR Configuration (Phase 2 + Phase 5)
    # Provider: "dashscope" (batch + realtime) or "openrouter" (batch-only)
    asr_provider: str = "dashscope"
    # DashScope ASR (used when asr_provider=dashscope, or for realtime WebSocket)
    dashscope_api_key: str = ""
    asr_model_name: str = "qwen3-asr-flash"
    asr_realtime_model_name: str = "qwen3-asr-flash-realtime"
    # OpenRouter STT (used when asr_provider=openrouter)
    openrouter_api_key: str = ""
    asr_openrouter_model: str = "google/chirp-3"

    # Video upload (Phase 2)
    video_upload_dir: str = "./uploads"
    max_video_size_mb: int = 300
    supported_video_formats: list[str] = [".mp4", ".webm", ".mov", ".avi", ".mkv"]

    # Phase 4 — Live audio capture toggles
    system_audio_enabled: bool = True
    mic_enabled: bool = True

    # Development helpers
    model_config = {"env_file": ".env", "env_file_encoding": "utf-8"}


VALID_ASR_PROVIDERS = frozenset({"dashscope", "openrouter"})


@lru_cache
def get_settings() -> Settings:
    s = Settings()
    logger.info(
        "Settings loaded: llm_model=%s  embedding_model=%s  asr_provider=%s",
        s.llm_model_name, s.embedding_model, s.asr_provider,
    )
    if s.asr_provider not in VALID_ASR_PROVIDERS:
        raise ValueError(
            f"Invalid ASR_PROVIDER '{s.asr_provider}'. "
            f"Must be one of: {', '.join(sorted(VALID_ASR_PROVIDERS))}"
        )
    return s