"""Provider pool management: primary / fallback pool routing."""

import structlog
from typing import Optional

from storage.backend_store import list_backends, get_pool_stats
from storage.models import Backend

logger = structlog.get_logger("sidecar_v2.pool_manager")


class PoolManager:
    """Manages provider pools and selects healthy backends for a given model.

    Priority: primary pool → fallback pool.
    Within a pool: healthy backends only, sorted by availability.
    """

    def __init__(self):
        self._pool_order = ["primary", "fallback"]

    def get_available_backends(
        self, canonical_model: str, pool: Optional[str] = None
    ) -> list[Backend]:
        """Get all healthy, enabled backends that serve a model, in pool order.

        Args:
            canonical_model: Canonical model name to match.
            pool: Optional pool filter (primary/fallback). None = all pools.

        Returns:
            List of ready backends sorted by pool priority, then RPM utilization.
        """
        backends: list[Backend] = []

        pools_to_check = [pool] if pool else self._pool_order
        for p in pools_to_check:
            pool_backends = list_backends(pool=p, enabled_only=True, decrypt_key=True)
            for b in pool_backends:
                if b.status == "healthy" and b.has_model(canonical_model):
                    backends.append(b)
            if pool:
                break

        return backends

    def get_any_healthy_backends(self, pool: Optional[str] = None) -> list[Backend]:
        """Get all healthy, enabled backends regardless of model."""
        backends: list[Backend] = []
        pools_to_check = [pool] if pool else self._pool_order
        for p in pools_to_check:
            pool_backends = list_backends(pool=p, enabled_only=True, decrypt_key=True)
            for b in pool_backends:
                if b.status == "healthy":
                    backends.append(b)
            if pool:
                break
        return backends

    def get_pool_status(self) -> dict:
        """Get pool summary for dashboard."""
        stats = get_pool_stats()
        result = {}
        for pool in self._pool_order:
            s = stats.get(pool, {"total": 0, "enabled": 0, "healthy": 0, "cooling": 0, "error": 0})
            result[pool] = s
        # Also include any other pools
        for pool, s in stats.items():
            if pool not in result:
                result[pool] = s
        return result

    def is_pool_available(self, canonical_model: str, pool: str = "primary") -> bool:
        """Check if a pool has any healthy backends for a model."""
        backends = self.get_available_backends(canonical_model, pool=pool)
        return len(backends) > 0

    def is_any_pool_available(self, canonical_model: str) -> bool:
        """Check if any pool has healthy backends for a model."""
        for pool in self._pool_order:
            if self.is_pool_available(canonical_model, pool):
                return True
        return False