export const PERFORMANCE_BUDGETS = Object.freeze({
  initialHtmlCriticalCss: 100 * 1024,
  initialApplicationJs: 120 * 1024,
  heroPoster: 220 * 1024,
  initialFonts: 120 * 1024,
  firstLiveScene: 650 * 1024,
  projectVideo: 2.5 * 1024 * 1024,
  projectVideoDurationSeconds: 10,
  projectVideoWidth: 1280,
  projectVideoHeight: 720,
  projectStill: 400 * 1024,
  chart: 100 * 1024,
  deferredProjectVisuals: 2.5 * 1024 * 1024,
  highTierExtras: 750 * 1024,
  deferredNonVideo: 3.5 * 1024 * 1024,
  imageSceneConcurrency: 2,
  videoConcurrency: 1,
  mobileTextureDimension: 2048,
  lowTierGpuEstimate: 96 * 1024 * 1024,
  highTierGpuEstimate: 192 * 1024 * 1024,
});

export const classifyArtifact = (path, source = '') => {
  if (path === 'index.html') return 'initial-html';
  if (/^assets\/index-[^/]+\.css$/u.test(path)) return 'critical-css';
  if (/^assets\/index-[^/]+\.js$/u.test(path) && /import\(/u.test(source)) return 'initial-application-js';
  if (/^assets\/(?:environment-high|high-tier)-[^/]+\.(?:js|avif|webp|png|jpe?g)$/u.test(path)) return 'high-tier-extras';
  if (/^assets\/environment-[^/]+\.js$/u.test(path)) return 'first-live-scene';
  if (/\.(?:woff2?|ttf|otf)$/u.test(path)) return 'initial-fonts';
  if (/^assets\/hero-[^/]+\.(?:avif|webp|png|jpe?g)$/u.test(path)) return 'hero-poster';
  if (/^assets\/project-[^/]+\.(?:webm|mp4)$/u.test(path)) return 'project-video';
  if (/^assets\/project-[^/]*chart[^/]*\.(?:avif|webp|png|jpe?g)$/u.test(path)) return 'chart';
  if (/^assets\/project-[^/]+\.(?:avif|webp|png|jpe?g|svg)$/u.test(path)) return 'project-still';
  if (/^(?:robots\.txt|sitemap\.xml|_headers\.example|_redirects\.example)$/u.test(path)) return 'release-metadata';
  throw new Error(`Artifact is unclassified: ${path}`);
};

const thresholdByTotal = Object.freeze({
  initialHtmlCriticalCss: PERFORMANCE_BUDGETS.initialHtmlCriticalCss,
  initialApplicationJs: PERFORMANCE_BUDGETS.initialApplicationJs,
  heroPoster: PERFORMANCE_BUDGETS.heroPoster,
  initialFonts: PERFORMANCE_BUDGETS.initialFonts,
  firstLiveScene: PERFORMANCE_BUDGETS.firstLiveScene,
  deferredProjectVisuals: PERFORMANCE_BUDGETS.deferredProjectVisuals,
  deferredNonVideo: PERFORMANCE_BUDGETS.deferredNonVideo,
  highTierExtras: PERFORMANCE_BUDGETS.highTierExtras,
});

export const evaluateBudgetTotals = (totals) => ({
  violations: Object.entries(thresholdByTotal)
    .filter(([budget, threshold]) => (totals[budget] ?? 0) > threshold)
    .map(([budget, threshold]) => ({ budget, actual: totals[budget], threshold })),
});

const violation = (budget, actual, threshold, id) => ({ budget, actual, threshold, ...(id === undefined ? {} : { id }) });
const finitePositiveInteger = (value) => Number.isInteger(value) && value > 0;

export const evaluateMediaAssetBudget = (asset, probe, transferBytes, assetClass = undefined) => {
  if (probe === null || typeof probe !== 'object') throw new Error(`Media probe evidence is required for ${asset?.id ?? 'unknown asset'}.`);
  if (!finitePositiveInteger(asset?.width) || !finitePositiveInteger(asset?.height)
    || !finitePositiveInteger(probe.width) || !finitePositiveInteger(probe.height)) {
    throw new Error(`Verified dimensions are required for ${asset?.id ?? 'unknown asset'}.`);
  }
  if (asset.width !== probe.width || asset.height !== probe.height || asset.mediaType !== probe.mediaType) {
    throw new Error(`Manifest and probe evidence disagree for ${asset.id}.`);
  }
  const violations = [];
  if (asset.mediaType.startsWith('video/')) {
    if (!finitePositiveInteger(asset.durationMs) || !finitePositiveInteger(probe.durationMs)
      || Math.abs(asset.durationMs - probe.durationMs) > 50) {
      throw new Error(`Verified duration is required for ${asset.id}.`);
    }
    if (transferBytes > PERFORMANCE_BUDGETS.projectVideo) violations.push(violation('projectVideo', transferBytes, PERFORMANCE_BUDGETS.projectVideo, asset.id));
    if (probe.durationMs > PERFORMANCE_BUDGETS.projectVideoDurationSeconds * 1_000) violations.push(violation('projectVideoDurationSeconds', probe.durationMs / 1_000, PERFORMANCE_BUDGETS.projectVideoDurationSeconds, asset.id));
    if (probe.width > PERFORMANCE_BUDGETS.projectVideoWidth) violations.push(violation('projectVideoWidth', probe.width, PERFORMANCE_BUDGETS.projectVideoWidth, asset.id));
    if (probe.height > PERFORMANCE_BUDGETS.projectVideoHeight) violations.push(violation('projectVideoHeight', probe.height, PERFORMANCE_BUDGETS.projectVideoHeight, asset.id));
  } else {
    if (asset.durationMs !== null || probe.durationMs !== null) throw new Error(`Still media cannot declare duration for ${asset.id}.`);
    const budget = assetClass === 'chart' ? 'chart' : 'projectStill';
    const threshold = PERFORMANCE_BUDGETS[budget];
    if (transferBytes > threshold) violations.push(violation(budget, transferBytes, threshold, asset.id));
  }
  return { violations };
};

const allocationBytes = (allocation, fields, label) => {
  for (const field of fields) {
    if (!finitePositiveInteger(allocation?.[field])) throw new Error(`${label} ${allocation?.id ?? 'unknown'} has invalid ${field}.`);
  }
  return fields.reduce((total, field) => total * allocation[field], 1);
};

export const evaluateRuntimeBudgetEvidence = (evidence) => {
  if (evidence?.schema !== 'portfolio-runtime-budget-evidence/v1' || !Array.isArray(evidence.tiers)) {
    throw new Error('Runtime budget evidence must use portfolio-runtime-budget-evidence/v1.');
  }
  const tierNames = evidence.tiers.map((tier) => tier?.tier).sort();
  if (JSON.stringify(tierNames) !== JSON.stringify(['high', 'low'])) {
    throw new Error('Runtime evidence must contain exactly one Low and High tier allocation ledger.');
  }
  const imageScene = evidence.peakRequests?.imageScene;
  const video = evidence.peakRequests?.video;
  if (!Number.isInteger(imageScene) || imageScene < 0 || !Number.isInteger(video) || video < 0) {
    throw new Error('Runtime request concurrency evidence is incomplete.');
  }
  const violations = [];
  if (imageScene > PERFORMANCE_BUDGETS.imageSceneConcurrency) violations.push(violation('imageSceneConcurrency', imageScene, PERFORMANCE_BUDGETS.imageSceneConcurrency));
  if (video > PERFORMANCE_BUDGETS.videoConcurrency) violations.push(violation('videoConcurrency', video, PERFORMANCE_BUDGETS.videoConcurrency));
  const tiers = evidence.tiers.map((tier) => {
    if (!['low', 'high'].includes(tier?.tier) || !Array.isArray(tier.textures) || !Array.isArray(tier.renderTargets)
      || !Number.isInteger(tier.geometryBytes) || tier.geometryBytes < 0) {
      throw new Error('Runtime tier allocation evidence is incomplete.');
    }
    let textureBytes = 0;
    for (const texture of tier.textures) {
      const base = allocationBytes(texture, ['width', 'height', 'bytesPerPixel', 'layers'], 'Texture');
      if (typeof texture.mipmapped !== 'boolean') throw new Error(`Texture ${texture?.id ?? 'unknown'} is missing mipmap evidence.`);
      textureBytes += Math.ceil(base * (texture.mipmapped ? 4 / 3 : 1));
      if (tier.tier === 'low' && (texture.width > PERFORMANCE_BUDGETS.mobileTextureDimension || texture.height > PERFORMANCE_BUDGETS.mobileTextureDimension)) {
        violations.push(violation('mobileTextureDimension', Math.max(texture.width, texture.height), PERFORMANCE_BUDGETS.mobileTextureDimension, texture.id));
      }
    }
    let renderTargetBytes = 0;
    for (const target of tier.renderTargets) {
      renderTargetBytes += allocationBytes(target, ['width', 'height', 'bytesPerPixel', 'attachments', 'samples'], 'Render target');
    }
    const runtimeAllowanceBytes = 32 * 1024 * 1024;
    const totalBytes = textureBytes + tier.geometryBytes + renderTargetBytes + runtimeAllowanceBytes;
    const budget = tier.tier === 'low' ? 'lowTierGpuEstimate' : 'highTierGpuEstimate';
    const threshold = PERFORMANCE_BUDGETS[budget];
    if (totalBytes > threshold) violations.push(violation(budget, totalBytes, threshold));
    return { tier: tier.tier, textureBytes, geometryBytes: tier.geometryBytes, renderTargetBytes, runtimeAllowanceBytes, totalBytes };
  });
  return { tiers, violations };
};