"""Application configuration split by architecture component."""

import os
from functools import lru_cache

from pydantic import BaseModel, Field
from pydantic_settings import (
    BaseSettings,
    PydanticBaseSettingsSource,
    SettingsConfigDict,
    YamlConfigSettingsSource,
)

DEFAULT_CONFIG_FILE = "config.yaml"
CONFIG_FILE_ENV = "G2S_CONFIG_FILE"


class ControllerConfig(BaseModel):
    api_prefix: str = "/api/v1"
    request_id_header: str = "X-Request-ID"


class ServiceConfig(BaseModel):
    provider_timeout_seconds: float = 10.0
    max_parallel_providers: int = 8


class BusinessLogicConfig(BaseModel):
    weight_round_scale: int = 2


class RepositoryConfig(BaseModel):
    redis_dsn: str = "redis://localhost:6379/0"
    price_cache_ttl_seconds: int = 900


class AdapterConfig(BaseModel):
    cdek_base_url: str = "https://api.cdek.ru/v2"
    cdek_timeout_seconds: float = 10.0


class ObservabilityConfig(BaseModel):
    service_name: str = "g2s-aggregator"
    otlp_endpoint: str = "http://localhost:4317"
    log_level: str = "INFO"


class AlertsConfig(BaseModel):
    telegram_enabled: bool = False
    telegram_bot_token: str | None = None
    telegram_chat_id: str | None = None


class Settings(BaseSettings):
    model_config = SettingsConfigDict(
        env_prefix="G2S_",
        env_nested_delimiter="__",
        extra="ignore",
    )

    controller: ControllerConfig = Field(default_factory=ControllerConfig)
    service: ServiceConfig = Field(default_factory=ServiceConfig)
    business_logic: BusinessLogicConfig = Field(default_factory=BusinessLogicConfig)
    repository: RepositoryConfig = Field(default_factory=RepositoryConfig)
    adapter: AdapterConfig = Field(default_factory=AdapterConfig)
    observability: ObservabilityConfig = Field(default_factory=ObservabilityConfig)
    alerts: AlertsConfig = Field(default_factory=AlertsConfig)

    @classmethod
    def settings_customise_sources(
        cls,
        settings_cls: type[BaseSettings],
        init_settings: PydanticBaseSettingsSource,
        env_settings: PydanticBaseSettingsSource,
        dotenv_settings: PydanticBaseSettingsSource,
        file_secret_settings: PydanticBaseSettingsSource,
    ) -> tuple[PydanticBaseSettingsSource, ...]:
        yaml_source = YamlConfigSettingsSource(
            settings_cls,
            yaml_file=os.getenv(CONFIG_FILE_ENV, DEFAULT_CONFIG_FILE),
        )
        return (
            init_settings,
            env_settings,
            dotenv_settings,
            yaml_source,
            file_secret_settings,
        )


@lru_cache(maxsize=1)
def get_settings() -> Settings:
    return Settings()