"""
Application configuration via Pydantic Settings.

All settings loaded from environment variables or .env file.
Project metadata (name, version, description) sourced from pyproject.toml.
"""
import tomllib
from dataclasses import dataclass
from functools import lru_cache
from pathlib import Path

from pydantic_settings import BaseSettings, SettingsConfigDict


@dataclass(frozen=True)
class ProjectMeta:
    """Project metadata from pyproject.toml (single source of truth)."""
    name: str
    version: str
    description: str


def _load_project_meta() -> ProjectMeta:
    """Load project metadata from pyproject.toml."""
    pyproject_path = Path(__file__).parent.parent.parent / "pyproject.toml"
    try:
        with open(pyproject_path, "rb") as f:
            data = tomllib.load(f)
            project = data.get("project", {})
            return ProjectMeta(
                name=str(project.get("name", "webber")).title(),
                version=str(project.get("version", "0.0.0")),
                description=str(project.get("description", "")),
            )
    except FileNotFoundError:
        return ProjectMeta(name="Webber", version="0.0.0", description="")


PROJECT = _load_project_meta()
__version__ = PROJECT.version


class Settings(BaseSettings):
    """Application settings loaded from environment."""

    # Application (from pyproject.toml)
    app_name: str = PROJECT.name
    app_version: str = PROJECT.version
    app_description: str = PROJECT.description
    debug: bool = False

    # Server
    host: str = "0.0.0.0"
    port: int = 8086

    # Logging
    log_level: str = "INFO"

    # CORS
    cors_origins: list[str] = ["http://localhost:3000", "http://localhost:8080"]
    cors_credentials: bool = True
    cors_methods: list[str] = ["*"]
    cors_headers: list[str] = ["*"]

    # LLM - Ollama (always hot in VRAM on tower-of-joy)
    ollama_url: str = "http://192.168.86.149:11434"
    ollama_agent_model: str = "mistral-nemo-large:latest"
    ollama_embed_model: str = "nomic-embed-text:latest"

    # Auth - Tatlock integration
    tatlock_api_url: str | None = "http://tatlock:8000"
    internal_api_key: str | None = None

    # Web search - SearXNG (use SEARXNG_URL env var to override)
    searxng_url: str = "http://searxng:8080"
    searxng_timeout: int = 10

    # Tool execution
    tool_timeout_seconds: int = 120
    sandbox_enabled: bool = True
    allowed_paths: list[str] | None = None

    # Database
    database_url: str = "sqlite+aiosqlite:///./webber.db"

    # Sessions & Context
    session_ttl_hours: int = 24
    max_context_tokens: int = 128000
    summarization_threshold: float = 0.8  # Summarize at 80% of max tokens
    summarization_target_tokens: int = 500  # Target summary size
    keep_recent_messages: int = 6  # Messages to keep unsummarized (3 turns)

    # Retry logic
    retry_max_attempts: int = 3  # Max retry attempts for transient failures
    retry_base_delay: float = 1.0  # Base delay in seconds
    retry_max_delay: float = 30.0  # Maximum delay in seconds

    model_config = SettingsConfigDict(
        env_file=".env",
        case_sensitive=False,
        extra="ignore",
        env_parse_none_str="",  # Treat empty string as None
    )

    @property
    def effective_allowed_paths(self) -> list[str]:
        """Return allowed_paths or empty list if None."""
        return self.allowed_paths or []


@lru_cache
def get_settings() -> Settings:
    """Cached settings singleton."""
    return Settings()