import assert from "node:assert/strict";
import { readFileSync } from "node:fs";
import { resolve } from "node:path";

const webuiRoot = resolve(import.meta.dirname, "..");
const repositoryRoot = resolve(webuiRoot, "..", "..");
const tokens = readFileSync(resolve(webuiRoot, "src/styles/tokens.css"), "utf8");
const app = readFileSync(resolve(webuiRoot, "src/App.tsx"), "utf8");
const settings = readFileSync(resolve(webuiRoot, "src/features/settings/SettingsPage.tsx"), "utf8");
const paletteControl = readFileSync(resolve(webuiRoot, "src/components/AppearancePaletteControl.tsx"), "utf8");

assert.match(tokens, /:root\[data-theme="dark"\]/, "dark token overrides are required");
assert.match(tokens, /color-scheme:\s*dark/, "native controls must receive the dark color scheme");
assert.match(app, /matchMedia\?\.\("\(prefers-color-scheme: dark\)"\)/, "system theme must follow OS changes");
assert.match(app, /dataset\.themePreference/, "the selected preference must remain inspectable");
assert.match(app, /dataset\.palette/, "the selected palette must be applied at the document root");
for (const theme of ["system", "light", "dark"]) {
  assert.match(settings, new RegExp(`value:\\s*"${theme}"`), `Settings must expose ${theme}`);
}
for (const palette of ["default", "civic_blue", "forest", "plum"]) {
  assert.match(paletteControl, new RegExp(`value:\\s*"${palette}"`), `Shared appearance control must expose ${palette}`);
}
assert.match(settings, /AppearancePaletteSelect/, "personal settings must use the shared palette control");
for (const relativePath of [
  "govoplan-admin/webui/src/features/admin/SystemSettingsPanel.tsx",
  "govoplan-tenancy/webui/src/features/admin/TenantSettingsPanel.tsx"
]) {
  const source = readFileSync(resolve(repositoryRoot, relativePath), "utf8");
  assert.match(source, /AppearancePaletteSelect/, `${relativePath} must use the shared palette control`);
  assert.match(source, /AppearancePalettePreview/, `${relativePath} must use the shared palette preview`);
}

const paletteContrasts = [
  { selector: "civic_blue", accent: "#245f91", foreground: "#ffffff" },
  { selector: "forest", accent: "#276749", foreground: "#ffffff" },
  { selector: "plum", accent: "#704b78", foreground: "#ffffff" }
];
for (const palette of paletteContrasts) {
  assert.match(tokens, new RegExp(`data-palette="${palette.selector}"[\\s\\S]*?--accent:\\s*${palette.accent}`, "i"));
  assert.ok(contrastRatio(palette.accent, palette.foreground) >= 4.5, `${palette.selector} accent contrast must meet WCAG AA`);
}
assert.ok(contrastRatio("#ef6b3a", "#242424") >= 4.5, "default accent badge contrast must meet WCAG AA");

const representativeModules = [
  "govoplan-campaign/webui/src/styles/campaign-workspace.css",
  "govoplan-calendar/webui/src/styles/calendar.css",
  "govoplan-files/webui/src/styles/file-manager.css",
  "govoplan-mail/webui/src/styles/mail-profiles.css",
];
for (const relativePath of representativeModules) {
  const css = readFileSync(resolve(repositoryRoot, relativePath), "utf8");
  assert.match(css, /var\(--/, `${relativePath} must consume shared theme tokens`);
}

console.log("Theme contract passed for core and representative module surfaces.");

function contrastRatio(first, second) {
  const left = relativeLuminance(first);
  const right = relativeLuminance(second);
  return (Math.max(left, right) + 0.05) / (Math.min(left, right) + 0.05);
}

function relativeLuminance(color) {
  const channels = color.slice(1).match(/../g).map((value) => parseInt(value, 16) / 255);
  const linear = channels.map((value) => value <= 0.04045 ? value / 12.92 : ((value + 0.055) / 1.055) ** 2.4);
  return 0.2126 * linear[0] + 0.7152 * linear[1] + 0.0722 * linear[2];
}