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

// BUG-1079 (TASK-site-button-contrast-20260928). This file began as the BUG-1078
// report-only contract; the report scope is gone and one site-wide definition
// replaced it, so the file now pins that definition. Every assertion that
// changed is listed with 原值 / 新值 / 原因 in
// docs/tasks/PROGRESS-site-button-contrast-20260928.md.
const css = readFileSync(new URL("../src/app/globals.css", import.meta.url), "utf8");
const cssNoComments = css.replace(/\/\*[\s\S]*?\*\//g, " ");
const buttonSource = readFileSync(new URL("../src/components/ui/button.tsx", import.meta.url), "utf8");
const calendarSource = readFileSync(new URL("../src/components/ui/calendar.tsx", import.meta.url), "utf8");
const pickerSource = readFileSync(new URL("../src/components/birth-date-picker.tsx", import.meta.url), "utf8");
const generateSource = readFileSync(new URL("../src/components/personal-report/generate-personal-report-button.tsx", import.meta.url), "utf8");

function blockTokens(opener: string): Map<string, string> {
  const start = css.indexOf(opener);
  assert.notEqual(start, -1, `missing block: ${opener}`);
  const body = css.slice(start, css.indexOf("\n}", start));
  return new Map([...body.matchAll(/--([\w-]+)\s*:\s*([^;]+);/g)].map((hit) => [hit[1], hit[2].trim()]));
}

function luminance(hex: string): number {
  const [r, g, b] = [1, 3, 5].map((i) => parseInt(hex.slice(i, i + 2), 16) / 255)
    .map((c) => (c <= 0.03928 ? c / 12.92 : ((c + 0.055) / 1.055) ** 2.4));
  return 0.2126 * r + 0.7152 * g + 0.0722 * b;
}

function contrast(a: string, b: string): number {
  const [hi, lo] = [luminance(a), luminance(b)].sort((x, y) => y - x);
  return (hi + 0.05) / (lo + 0.05);
}

function rule(selector: string): string {
  const escaped = selector.replace(/[.*+?^${}()|[\]\\]/g, "\\$&");
  const hit = cssNoComments.match(new RegExp(`(?:^|[}\\n])\\s*${escaped}\\s*\\{([^}]*)\\}`));
  assert.ok(hit, `missing rule: ${selector}`);
  return hit[1];
}

test("the unlayered element rules no longer override button utilities", () => {
  // Root cause of BUG-1078 / BUG-1079: unlayered `button { color: inherit; }` beat
  // every layered Tailwind text utility.
  assert.doesNotMatch(cssNoComments, /(^|[}\n])\s*button\s*\{\s*color\s*:/);
  assert.doesNotMatch(cssNoComments, /(^|[}\n])\s*button:disabled\s*\{/);
  // Raw <button>s keep the old fade at the old specificity; <Button> is left to its utilities.
  assert.match(cssNoComments, /button:disabled:where\(:not\(\[data-slot="button"\]\)\) \{ cursor: default; opacity: \.45; \}/);
});

test("one solid-button token pair per theme, readable at 4.5:1 or better", () => {
  const light = blockTokens(":root {\n  color-scheme: light;");
  const preferred = blockTokens(':root:not([data-theme="light"]) {');
  const pinned = blockTokens(':root[data-theme="dark"] {');
  assert.equal(light.get("color-action-fill"), "#a9583e");
  assert.equal(light.get("color-on-action-fill"), "#fbfaf7");
  assert.equal(light.get("color-action-fill-hover"), "#8f4630");
  assert.equal(light.get("color-action-fill-disabled"), "var(--color-canvas-strong)");
  assert.equal(light.get("color-on-action-fill-disabled"), "var(--color-ink-tertiary)");
  assert.ok(contrast("#fbfaf7", "#a9583e") >= 4.5);
  assert.ok(contrast("#fbfaf7", "#8f4630") >= 4.5);
  for (const dark of [preferred, pinned]) {
    assert.equal(dark.get("color-action-fill"), "#8f4a33");
    assert.equal(dark.get("color-on-action-fill"), "#f2f0ea");
    assert.equal(dark.get("color-action-fill-hover"), "color-mix(in srgb, #8f4a33 94%, #f2f0ea)");
  }
  assert.ok(contrast("#f2f0ea", "#8f4a33") >= 4.5);
  // D6: --color-primary keeps its mapping; text-primary icons still use it.
  assert.match(css, /--color-primary: var\(--color-action\);\n  --color-primary-foreground: var\(--color-on-dark\);/);
  // D2: the brand coral stays for non-button fills.
  assert.equal(light.get("color-action-strong"), "#cc785c");
});

test("the shared Button, .button-primary, the composer controls and the calendar read the same fill", () => {
  assert.match(buttonSource, /default: "bg-action-fill text-on-action-fill hover:bg-action-fill-hover disabled:bg-action-fill-disabled disabled:text-on-action-fill-disabled disabled:opacity-100"/);
  // Non-solid variants keep the old 45% disabled fade (red line 3).
  assert.match(buttonSource, /disabled:pointer-events-none disabled:opacity-45/);
  assert.match(buttonSource, /outline: "border-border bg-background hover:bg-muted hover:text-foreground"/);
  assert.match(buttonSource, /data-slot="button"/);
  assert.match(rule(".button-primary"), /background: var\(--color-action-fill\); color: var\(--color-on-action-fill\);/);
  assert.match(rule(".composer .composer-row-end > button"), /color: var\(--color-on-action-fill\);[^}]*background: var\(--color-action-fill\);/);
  assert.match(rule(".composer .composer-stop"), /background: var\(--color-action-fill\);/);
  for (const state of ["selected-single", "range-start", "range-end"]) {
    assert.match(calendarSource, new RegExp(`data-\\[${state}=true\\]:bg-action-fill data-\\[${state}=true\\]:text-on-action-fill`));
  }
  assert.doesNotMatch(calendarSource, /bg-primary|text-primary-foreground/);
  // The `!` rescue for the selected day compensated for the root cause and is gone.
  assert.doesNotMatch(pickerSource, /text-primary-foreground!/);
});

test("solid disabled buttons are grey at full opacity, never a faded clay", () => {
  for (const selector of [".button-primary:disabled", ".composer .composer-row-end > button:disabled"]) {
    const body = rule(selector);
    assert.match(body, /opacity: 1;/);
    assert.match(body, /background: var\(--color-action-fill-disabled\);/);
    assert.match(body, /color: var\(--color-on-action-fill-disabled\);/);
  }
});

test(".danger-primary keeps its own label colour instead of taking the new fill ink", () => {
  const body = rule(".danger-primary");
  assert.match(body, /background: var\(--color-danger\);/);
  assert.match(body, /color: var\(--color-on-dark\);/);
  assert.ok(contrast("#fbfaf7", "#9a2f2f") >= 4.5, "light 7.13");
  assert.ok(contrast("#241f1c", "#e08573") >= 4.5, "dark 6.04");
});

test("the BUG-1078 report-only override is gone; the selected export preset stays neutral", () => {
  assert.doesNotMatch(css, /--report-button-fill|--report-button-ink/);
  assert.doesNotMatch(cssNoComments, /report-center-generate/);
  assert.doesNotMatch(generateSource, /report-center-generate/);
  assert.doesNotMatch(cssNoComments, /\[class~="bg-primary"\]/);
  const preset = rule('.report-export-presets [aria-pressed="true"]');
  assert.doesNotMatch(preset, /--color-action-soft|--color-action\b/);
  assert.match(preset, /--color-ink/);
});