import type {
  AppCapability,
  CapabilitiesService,
  CapabilitySnapshot,
} from "../app/types";

export const evaluateCapabilitySnapshot = (
  snapshot: CapabilitySnapshot,
): AppCapability => {
  if (!snapshot.hasMediaDevices) {
    return {
      ...snapshot,
      canRunDemo: false,
      failureReason: "This browser does not expose microphone capture APIs.",
    };
  }

  if (!snapshot.hasWebGPU) {
    return {
      ...snapshot,
      canRunDemo: false,
      failureReason: "WebGPU is unavailable, so local model execution cannot start.",
    };
  }

  if (!snapshot.hasAudioWorklet) {
    return {
      ...snapshot,
      canRunDemo: false,
      failureReason: "AudioWorklet support is unavailable, so live capture is unreliable.",
    };
  }

  return {
    ...snapshot,
    canRunDemo: true,
    failureReason: null,
  };
};

export class BrowserCapabilitiesService implements CapabilitiesService {
  async detect(): Promise<AppCapability> {
    const snapshot: CapabilitySnapshot = {
      hasWebGPU: typeof navigator !== "undefined" && "gpu" in navigator,
      hasMediaDevices:
        typeof navigator !== "undefined" &&
        typeof navigator.mediaDevices?.getUserMedia === "function",
      hasAudioWorklet:
        typeof window !== "undefined" &&
        typeof window.AudioWorkletNode !== "undefined",
      hasCrossOriginIsolation:
        typeof globalThis !== "undefined" &&
        globalThis.crossOriginIsolated === true,
    };

    return evaluateCapabilitySnapshot(snapshot);
  }
}