"""Typed configuration via pydantic-settings (12-factor).

Base `Settings` carries everything shared across services. A service imports
this and reads only the fields it needs. All values come from environment
variables (or `.env`); nothing is hardcoded.

Per-service entrypoints may subclass `Settings` to add their own fields
(e.g. the bot adds `BOT_TOKEN`, `API_URL`). See docs/ARCHITECTURE.md §11 for the
full env reference.
"""

from __future__ import annotations

from functools import lru_cache
from typing import Annotated, Literal

from pydantic import Field, field_validator
from pydantic_settings import BaseSettings, NoDecode, SettingsConfigDict

Env = Literal["dev", "staging", "prod"]
RefundPolicy = Literal["all", "infra_only"]


class Settings(BaseSettings):
    """Application configuration. See docs/ARCHITECTURE.md §11."""

    model_config = SettingsConfigDict(
        env_file=".env",
        env_file_encoding="utf-8",
        extra="ignore",
        case_sensitive=False,
    )

    # --- runtime ---
    env: Env = "dev"
    log_level: str = "INFO"

    # --- datastores / brokers ---
    database_url: str = Field(..., description="async DSN: postgresql+asyncpg://...")
    redis_url: str = "redis://redis:6379/0"
    rabbitmq_url: str = Field(..., description="amqp://user:pass@host:5672//")

    # --- RabbitMQ tuning ---
    mq_prefetch_extract: int = 1
    mq_prefetch_analyze: int = 3
    mq_prefetch_notify: int = 5
    mq_prefetch_prescreen: int = 1
    mq_max_attempts: int = 5
    mq_retry_base_ms: int = 2000
    mq_management_enabled: bool = True
    mq_management_timeout: float = 10.0
    mq_requeue_batch_size: int = 50

    # --- object storage (MinIO) ---
    s3_endpoint_url: str
    s3_access_key: str
    s3_secret_key: str
    s3_bucket: str = "contract-check-docs"
    s3_region: str = "us-east-1"
    s3_server_side_encryption: bool = False
    doc_retention_days: int = 7
    text_retention_days: int = 30
    max_upload_bytes: int = Field(
        default=25 * 1024 * 1024,
        description="Maximum uploaded file size in bytes (default 25 MiB).",
    )

    # --- billing ---
    refund_policy: RefundPolicy = "all"
    plans_enabled: bool = Field(
        default=False,
        description="Enable subscription quota logic (migration 0011). False keeps the legacy credits-only behavior.",
    )
    yookassa_enabled: bool = Field(default=False)
    yookassa_shop_id: str = ""
    yookassa_secret_key: str = ""
    yookassa_return_base_url: str = ""
    price_per_doc_kopecks: int = 19900
    billing_return_jwt_secret: str = Field(
        default="",
        description="HS256 secret for signing short-lived pay-page tokens.",
    )
    billing_return_token_ttl_minutes: int = 15
    refund_window_days: int = 14
    refund_full_usage_threshold: float = 0.20

    # --- observability (empty disables) ---
    sentry_dsn: str = ""

    # --- LLM provider ---
    llm_provider: str = "ollama_cloud"
    ollama_host: str = ""
    ollama_api_key: str = ""
    ollama_model: str = "qwen2.5:14b"
    ollama_fallback_model: str = "qwen2.5:7b"
    ollama_temperature: float = 0.2
    ollama_num_predict: int = 3072
    ollama_timeout: float = 120.0
    ollama_max_concurrency: int = 3

    # --- YandexGPT provider ---
    yandexgpt_api_key: str = ""
    yandexgpt_folder_id: str = ""
    yandexgpt_model: str = "yandexgpt-lite"
    yandexgpt_fallback_model: str = ""
    yandexgpt_base_url: str = "https://llm.api.cloud.yandex.net"
    yandexgpt_completion_path: str = "/foundationModels/v1/completion"
    yandexgpt_temperature: float = 0.2
    yandexgpt_max_tokens: int = 3072
    yandexgpt_timeout: float = 120.0
    yandexgpt_max_concurrency: int = 3

    # --- API ---
    api_host: str = "0.0.0.0"
    api_port: int = 8000
    api_metrics_port: int = 9100
    b2b_default_rate_limit_rps: int = 3
    metrics_bearer_token: str = Field(
        default="",
        description="Bearer token protecting /metrics. Empty leaves the endpoint open.",
    )

    # SSE streaming of report status (GET /api/v1/reports/{id}/events).
    sse_poll_interval_seconds: float = 1.0
    sse_max_stream_seconds: float = 300.0

    # Comma-separated browser origins allowed to call the API (CORS).
    # Empty disables CORS entirely (no browser clients).
    cors_origins: Annotated[list[str], NoDecode] = []

    @field_validator("cors_origins", mode="before")
    @classmethod
    def _split_cors_origins(cls, v: object) -> object:
        """Accept comma-separated strings (the documented .env format) or lists."""
        if isinstance(v, str):
            value = v.split("#", 1)[0]  # tolerate inline comments
            return [origin.strip() for origin in value.split(",") if origin.strip()]
        return v

    # --- auth (JWT + Telegram identity verification) ---
    telegram_bot_token: str = Field(
        "", description="Telegram bot token; used to verify Login Widget / Mini App signatures"
    )
    jwt_secret: str = Field(..., description="HS256 secret for signing user JWTs")
    jwt_algorithm: str = "HS256"
    jwt_access_ttl_minutes: int = 24 * 60  # 24 hours default; tune per env
    jwt_refresh_ttl_days: int = 30  # refresh-token lifetime for webUI auth

    # --- webUI auth (email + password) ---
    web_auth_enabled: bool = Field(
        default=True,
        description="Toggle for /api/v1/auth/{register,login,...} email-password routes",
    )
    password_reset_ttl_minutes: int = 60  # reset-token validity window
    web_app_base_url: str = Field(
        default="http://localhost:5173",
        description="Base URL of the webUI SPA — used to build password-reset links",
    )
    # Minimum password length enforced at register / reset.
    password_min_length: int = 8

    # --- auth rate limiting ---
    auth_rate_limit_ip_rps: int = Field(
        default=5,
        description="Per-IP token-bucket rate for public auth endpoints (login, register, etc.).",
    )
    auth_rate_limit_email_rps: int = Field(
        default=2,
        description="Per-recipient token-bucket rate for mail-sending auth endpoints.",
    )

    # --- passkeys (WebAuthn) ---
    passkey_enabled: bool = Field(
        default=True,
        description="Toggle for /api/v1/auth/passkeys/* routes",
    )
    passkey_rp_id: str = Field(
        default="localhost",
        description="WebAuthn Relying Party id (effective domain of the webUI)",
    )
    passkey_rp_name: str = Field(
        default="Контракт-чек",
        description="Human-readable Relying Party name shown in the browser prompt",
    )
    # Comma-separated origins allowed as WebAuthn callers (scheme://host:port).
    passkey_rp_origins: Annotated[list[str], NoDecode] = ["http://localhost:5173"]

    @field_validator("passkey_rp_origins", mode="before")
    @classmethod
    def _split_passkey_rp_origins(cls, v: object) -> object:
        """Accept comma-separated strings (the documented .env format) or lists."""
        if isinstance(v, str):
            value = v.split("#", 1)[0]  # tolerate inline comments
            return [origin.strip() for origin in value.split(",") if origin.strip()]
        return v

    passkey_challenge_ttl_seconds: int = 120  # ceremony challenge validity window

    # --- magic-link auth (passwordless email login) ---
    magic_link_enabled: bool = Field(
        default=True,
        description="Toggle for /api/v1/auth/magic-link/* routes",
    )
    magic_link_ttl_minutes: int = 15  # magic-link token validity window

    # --- admin panel (server-rendered, mounted at /admin in the api) ---
    web_admin_enabled: bool = Field(
        default=True,
        description="Toggle for the /admin management UI (users, future subscriptions)",
    )
    admin_required_role: str = Field(
        default="admin",
        description="users.role value required to enter /admin (must match the DB CHECK constraint)",
    )
    admin_default_email: str = Field(
        default="admin@contract-check.local",
        description="Default admin panel login email (auto-created if no admin exists)",
    )
    admin_default_password: str = Field(
        default="",
        description="Default admin panel password. Empty disables auto-admin creation.",
    )

    # --- SMTP (notification transport; empty host disables sending) ---
    smtp_host: str = ""
    smtp_port: int = 587
    smtp_username: str = ""
    smtp_password: str = ""
    smtp_from: str = Field(
        default="no-reply@contract-check.local",
        description="From: address used by the notify worker",
    )
    smtp_use_tls: bool = True  # STARTTLS on port 587; set false for plain SMTP

    # --- logging ---
    log_format: str = "json"  # json | console

    # --- analysis ---
    chunk_size_chars: int = 10000

    # --- prescreen ---
    # Defaults mirror .env.example (the documented production intent).
    prescreen_enabled: bool = True
    prescreen_confidence_threshold: float = 0.75
    prescreen_high_value_threshold: float = 100_000.0
    prescreen_auto_approve: bool = False
    prescreen_llm_fallback_enabled: bool = False
    prescreen_llm_fallback_threshold: float = 0.75
    prescreen_llm_max_chars: int = 20_000

    @property
    def json_logs(self) -> bool:
        """JSON logs in staging/prod, pretty console in dev.

        Override with LOG_FORMAT=json|console.
        """
        fmt = self.log_format.lower()
        if fmt == "console":
            return False
        if fmt == "json":
            return True
        return self.env != "dev"


@lru_cache
def get_settings() -> Settings:
    """Cached settings singleton. Call `get_settings.cache_clear()` to reset."""
    return Settings()  # type: ignore[call-arg]