"""LLM routing configuration API."""
from __future__ import annotations

from fastapi import APIRouter, Depends, HTTPException

from app.core.deps import require_admin, require_readonly
from app.models.user import User
from app.schemas import LlmRoutingConfigIn, LlmRoutingConfigOut, ProviderModelsOut
from app.services.model_catalog import catalog_by_tier, get_entry
from app.services.model_config import (
    LlmRoutingConfig,
    available_backends,
    get_routing_config,
    save_routing_config,
)
from app.services.model_discovery import list_all_provider_models

router = APIRouter(prefix="/api/llm", tags=["llm"])

ROUTING_STRATEGY = (
    "Local Ollama first for triage and reasoning. On escalation, cloud providers are tried "
    "in order: Gemini API → DeepSeek → OpenRouter. Within each cost tier (economy, premium), "
    "each provider is attempted before moving to the next tier."
)

_MODEL_ID_FIELDS = (
    "local_model_id",
    "economy_gemini_id",
    "economy_deepseek_id",
    "economy_openrouter_id",
    "premium_gemini_id",
    "premium_deepseek_id",
    "premium_openrouter_id",
)


@router.get("/routing", response_model=LlmRoutingConfigOut)
async def get_llm_routing(_: User = Depends(require_readonly)):
    cfg = await get_routing_config()
    return LlmRoutingConfigOut(
        config=cfg.to_dict(),
        catalog=catalog_by_tier(),
        available_backends=available_backends(),
        strategy=ROUTING_STRATEGY,
    )


@router.get("/models/available", response_model=ProviderModelsOut)
async def get_available_models(_: User = Depends(require_readonly)):
    """Live model lists from Ollama, Gemini, DeepSeek, and OpenRouter APIs."""
    data = await list_all_provider_models()
    return ProviderModelsOut(providers=data["providers"], routing_order=data["routing_order"])


@router.put("/routing", response_model=LlmRoutingConfigOut)
async def update_llm_routing(body: LlmRoutingConfigIn, _: User = Depends(require_admin)):
    current = await get_routing_config()
    data = body.model_dump(exclude_unset=True)

    for field in (
        *_MODEL_ID_FIELDS,
        "auto_escalate",
        "max_tier",
    ):
        if field in data and data[field] is not None:
            setattr(current, field, data[field])

    if body.cloud_provider_order is not None:
        current.cloud_provider_order = body.cloud_provider_order

    for fid in _MODEL_ID_FIELDS:
        val = getattr(current, fid)
        if val and not get_entry(val):
            raise HTTPException(status_code=400, detail=f"Unknown model id: {val}")

    if current.max_tier not in ("local", "economy", "premium"):
        raise HTTPException(status_code=400, detail="max_tier must be local, economy, or premium")

    await save_routing_config(current)
    return LlmRoutingConfigOut(
        config=current.to_dict(),
        catalog=catalog_by_tier(),
        available_backends=available_backends(),
        strategy=ROUTING_STRATEGY,
    )