/**
 * Web Renderer Utilities for Client-Side Rendering
 * 
 * This module provides utilities for checking browser compatibility
 * and rendering videos directly in the browser using @remotion/web-renderer.
 */

import {
  canRenderMediaOnWeb,
  getEncodableVideoCodecs,
  getEncodableAudioCodecs,
  type CanRenderIssue,
  type WebRendererVideoCodec,
  type WebRendererAudioCodec,
} from '@remotion/web-renderer';

// Types
export interface CSRSupportResult {
  canRender: boolean;
  issues: CanRenderIssue[];
  resolvedVideoCodec: WebRendererVideoCodec;
  resolvedAudioCodec: WebRendererAudioCodec | null;
  resolvedOutputTarget: 'web-fs' | 'arraybuffer';
}

export interface AvailableCodecs {
  videoCodecs: WebRendererVideoCodec[];
  audioCodecs: WebRendererAudioCodec[];
}

export type RenderMode = 'csr' | 'ssr' | 'ssr-local';

export interface RenderOptions {
  mode: RenderMode;
  container?: 'mp4' | 'webm';
  videoCodec?: WebRendererVideoCodec;
  audioCodec?: WebRendererAudioCodec;
  videoBitrate?: 'very-low' | 'low' | 'medium' | 'high' | 'very-high';
  audioBitrate?: 'very-low' | 'low' | 'medium' | 'high' | 'very-high';
}

/**
 * Check if the current browser supports Client-Side Rendering
 */
export async function checkCSRSupport(
  width: number,
  height: number,
  options?: {
    container?: 'mp4' | 'webm';
    videoCodec?: WebRendererVideoCodec;
    audioCodec?: WebRendererAudioCodec;
  }
): Promise<CSRSupportResult> {
  try {
    const result = await canRenderMediaOnWeb({
      container: options?.container ?? 'mp4',
      videoCodec: options?.videoCodec ?? 'h264',
      audioCodec: options?.audioCodec,
      width,
      height,
    });

    return {
      canRender: result.canRender,
      issues: result.issues,
      resolvedVideoCodec: result.resolvedVideoCodec,
      resolvedAudioCodec: result.resolvedAudioCodec,
      resolvedOutputTarget: result.resolvedOutputTarget,
    };
  } catch (error) {
    // WebCodecs API not available
    return {
      canRender: false,
      issues: [{
        type: 'webcodecs-unavailable',
        message: 'WebCodecs API is not available in this browser',
        severity: 'error',
      }],
      resolvedVideoCodec: 'h264',
      resolvedAudioCodec: null,
      resolvedOutputTarget: 'arraybuffer',
    };
  }
}

/**
 * Get available video and audio codecs for the current browser
 */
export async function getAvailableCodecs(
  container: 'mp4' | 'webm' = 'mp4'
): Promise<AvailableCodecs> {
  try {
    const [videoCodecs, audioCodecs] = await Promise.all([
      getEncodableVideoCodecs(container),
      getEncodableAudioCodecs(container),
    ]);

    return { videoCodecs, audioCodecs };
  } catch (error) {
    // Fallback for browsers without WebCodecs
    return {
      videoCodecs: [],
      audioCodecs: [],
    };
  }
}

/**
 * Format CSR error messages for user display
 */
export function formatCSRErrors(issues: CanRenderIssue[]): string[] {
  return issues
    .filter(issue => issue.severity === 'error')
    .map(issue => issue.message);
}

/**
 * Format CSR warnings for user display
 */
export function formatCSRWarnings(issues: CanRenderIssue[]): string[] {
  return issues
    .filter(issue => issue.severity === 'warning')
    .map(issue => issue.message);
}

/**
 * Check if WebCodecs API is available in the browser
 */
export function isWebCodecsAvailable(): boolean {
  return typeof VideoEncoder !== 'undefined' && typeof AudioEncoder !== 'undefined';
}

/**
 * Get recommended render mode based on browser support
 */
export async function getRecommendedRenderMode(
  width: number,
  height: number
): Promise<RenderMode> {
  const support = await checkCSRSupport(width, height);
  return support.canRender ? 'csr' : 'ssr';
}

/**
 * Get default render options with browser-specific adjustments
 */
export async function getDefaultRenderOptions(
  width: number,
  height: number
): Promise<RenderOptions> {
  const support = await checkCSRSupport(width, height);

  return {
    mode: support.canRender ? 'csr' : 'ssr',
    container: 'mp4',
    videoCodec: support.resolvedVideoCodec,
    audioCodec: support.resolvedAudioCodec ?? undefined,
    videoBitrate: 'high',
    audioBitrate: 'medium',
  };
}

/**
 * Download a blob as a file
 */
export function downloadBlob(blob: Blob, filename: string): void {
  const url = URL.createObjectURL(blob);
  const a = document.createElement('a');
  a.href = url;
  a.download = filename;
  document.body.appendChild(a);
  a.click();
  document.body.removeChild(a);
  URL.revokeObjectURL(url);
}