"""FastAPI dependency injection — provides shared singletons to route handlers."""

from typing import Annotated

from fastapi import Depends

from navi.config import settings
from navi.context_providers._loader import ContextProviderRegistry
from navi.core import (
    Agent,
    BackendRegistry,
    PgSessionStore,
    ProfileRegistry,
    SessionStore,
    SqliteSessionStore,
    ToolRegistry,
    build_default_registries,
)
from navi.memory import MemoryStore
from navi.memory.sqlite_store import SqliteMemoryStore
from navi.workers import Worker, build_default_workers


def _make_session_store() -> SessionStore:
    if settings.database_url:
        return PgSessionStore(settings.database_url)
    return SqliteSessionStore(settings.db_path)


def _make_memory_store() -> MemoryStore:
    if settings.database_url:
        return MemoryStore(settings.database_url)
    return SqliteMemoryStore(settings.db_path)


_memory_store = _make_memory_store()
_registries: tuple[ToolRegistry, ProfileRegistry, BackendRegistry, ContextProviderRegistry] | None = None


def get_memory_store() -> MemoryStore:
    return _memory_store


def get_registries() -> tuple[ToolRegistry, ProfileRegistry, BackendRegistry, ContextProviderRegistry]:
    global _registries
    if _registries is None:
        _registries = build_default_registries(
            memory_store=_memory_store,
            session_store=_session_store,
        )
    return _registries


def get_tool_registry() -> ToolRegistry:
    return get_registries()[0]


def get_profile_registry() -> ProfileRegistry:
    return get_registries()[1]


def get_backend_registry() -> BackendRegistry:
    return get_registries()[2]


def get_cp_registry() -> ContextProviderRegistry:
    return get_registries()[3]


_session_store = _make_session_store()
_workers: list[Worker] = build_default_workers()


def get_session_store() -> SessionStore:
    return _session_store


def get_workers() -> list[Worker]:
    return _workers


def get_agent(
    session_store: Annotated[SessionStore, Depends(get_session_store)],
    profile_registry: Annotated[ProfileRegistry, Depends(get_profile_registry)],
    tool_registry: Annotated[ToolRegistry, Depends(get_tool_registry)],
    backend_registry: Annotated[BackendRegistry, Depends(get_backend_registry)],
    cp_registry: Annotated[ContextProviderRegistry, Depends(get_cp_registry)],
) -> Agent:
    return Agent(session_store, profile_registry, tool_registry, backend_registry,
                 workers=get_workers(), memory_store=_memory_store, cp_registry=cp_registry)