from __future__ import annotations

from abc import ABC, abstractmethod
from dataclasses import dataclass

from app.config.models import InfinityMirrorConfig
from app.core.types import PreviewFrame


@dataclass
class OutputResult:
    ok: bool
    message: str = ""
    packets_sent: int = 0
    device_count: int = 0


@dataclass(frozen=True)
class ControllerMetrics:
    fps: float | None = None
    live_devices: int = 0
    sampled_devices: int = 0
    total_devices: int = 0
    source: str = ""


@dataclass(frozen=True)
class OutputDiagnostics:
    backend_id: str
    backend_name: str
    output_enabled: bool
    worker_running: bool
    target_fps: float
    send_fps: float = 0.0
    last_send_time_ms: float = 0.0
    frames_submitted: int = 0
    frames_sent: int = 0
    stale_frame_drops: int = 0
    send_failures: int = 0
    packets_last_frame: int = 0
    devices_last_frame: int = 0
    packets_sent_total: int = 0
    last_message: str = ""
    send_budget_misses: int = 0
    last_schedule_slip_ms: float = 0.0
    controller_fps: float | None = None
    controller_live_devices: int = 0
    controller_sampled_devices: int = 0
    controller_total_devices: int = 0
    controller_source: str = ""


class OutputBackend(ABC):
    backend_id: str
    display_name: str
    supports_live_output: bool = False

    def start(self) -> None:
        """Hook for backends that need to allocate resources."""

    def stop(self) -> None:
        """Hook for backends that need to release resources."""

    def controller_metrics(self, config: InfinityMirrorConfig) -> ControllerMetrics | None:
        """Optional hook for backends that can report controller-side receive metrics."""
        return None

    @abstractmethod
    def send_frame(self, config: InfinityMirrorConfig, frame: PreviewFrame) -> OutputResult:
        raise NotImplementedError