"""
Models router - serves available AI models based on user subscription plan.

Single source of truth flow:
  config.py (PLAN_LIMITS + MODEL_CATALOG) → this router → frontend

To add/remove/rename a model, only edit config.py.
"""
from fastapi import APIRouter, Depends
from app.dependencies import get_current_user
from app.database import get_supabase
from app.config import PLAN_LIMITS, MODEL_CATALOG, DEFAULT_MODELS
from typing import List, Optional
from pydantic import BaseModel
import logging

logger = logging.getLogger(__name__)
router = APIRouter(prefix="/models", tags=["Models"])


# ─── Response Models ───────────────────────────────────────────────────────────

class AvailableModel(BaseModel):
    id: str
    name: str
    provider: str
    badge: str
    description: Optional[str] = None
    is_default: bool = False


class ModelsResponse(BaseModel):
    models: List[AvailableModel]
    plan: str
    default_model: Optional[str] = None
    has_premium_access: bool
    upgrade_label: Optional[str] = None


# ─── Helpers ───────────────────────────────────────────────────────────────────

def _get_user_plan(user_id: str) -> str:
    """Get user's current subscription plan."""
    supabase = get_supabase()
    result = supabase.table("subscriptions") \
        .select("plan") \
        .eq("user_id", user_id) \
        .eq("status", "active") \
        .execute()
    return result.data[0]["plan"] if result.data else "free"


# ─── Endpoint ─────────────────────────────────────────────────────────────────

@router.get("/available", response_model=ModelsResponse)
async def get_available_models(user=Depends(get_current_user)):
    """
    Returns the list of AI models the user can access based on their plan.
    Frontend uses this to populate model selection dynamically.

    - free: gets a default model for preview/testing
    - starter: Fireworks AI models
    - pro: Fireworks + OpenAI + Anthropic + Google
    - enterprise: all models
    """
    plan = _get_user_plan(user.id)
    plan_config = PLAN_LIMITS.get(plan, PLAN_LIMITS["free"])
    allowed_model_ids = plan_config.get("models", [])

    # Enterprise wildcard → resolve to all catalog models
    if "*" in allowed_model_ids:
        allowed_model_ids = list(MODEL_CATALOG.keys())

    # Build model list from catalog metadata
    default_model_id = DEFAULT_MODELS.get(plan)
    models: List[AvailableModel] = []

    for model_id in allowed_model_ids:
        meta = MODEL_CATALOG.get(model_id)
        if not meta:
            logger.warning(f"Model '{model_id}' in PLAN_LIMITS[{plan}] but not in MODEL_CATALOG — skipping")
            continue

        models.append(AvailableModel(
            id=model_id,
            name=meta["name"],
            provider=meta["provider"],
            badge=meta["badge"],
            description=meta.get("description"),
            is_default=(model_id == default_model_id),
        ))

    # Determine upgrade messaging
    has_premium = plan in ("business", "agency", "enterprise")
    upgrade_label = None
    if plan == "free":
        upgrade_label = "Upgrade to Starter for more AI models and messaging channels"
    elif plan == "starter":
        upgrade_label = "Upgrade to Business for GPT-4o, Claude, and Gemini"

    return ModelsResponse(
        models=models,
        plan=plan,
        default_model=default_model_id,
        has_premium_access=has_premium,
        upgrade_label=upgrade_label,
    )