/**
 * ╔═══════════════════════════════════════════════════════════════════════════╗
 * ║  THE COLOUR FILE. THIS IS THE ONE YOU EDIT.                              ║
 * ╚═══════════════════════════════════════════════════════════════════════════╝
 *
 * Two ramps — one light, one dark — and nothing else. Change a value here and
 * every screen in the app that uses the corresponding role follows, because no
 * screen names a colour directly: they all read semantic roles off the theme,
 * and `tokens.ts` is the single place those roles are mapped onto these ramps.
 *
 * ── HOW TO CHANGE A COLOUR ──────────────────────────────────────────────────
 *   1. Edit the value in `light` and its counterpart in `dark`.
 *   2. Run `node scripts/checkContrast.js`. It measures every text-on-surface
 *      pairing in both ramps and fails if any drops under AA.
 *   3. If it fails, the colour is not usable at that role — adjust lightness
 *      rather than deleting the check.
 *
 * Both ramps MUST declare exactly the same keys: `buildTheme` in `tokens.ts`
 * maps one shape onto the semantic roles, and TypeScript enforces the match
 * through the `Palette` type below. A key added to one is a compile error until
 * it is added to the other, which is deliberate — a role that only exists in
 * light mode is a screen that breaks in dark mode.
 *
 * ── THE DESIGN LANGUAGE ─────────────────────────────────────────────────────
 * Royal blue on white, with deep navy for the full-bleed moments. Clean,
 * airy, institutional: a white card on a cool blue-grey ground, one vivid blue
 * for everything tappable, and navy reserved for the sign-in wash and the
 * header band on Home. The neutrals are tinted a few degrees toward the brand
 * hue, so the greys read as part of the blue family rather than as flat grey.
 *
 * ── THE RULES THESE VALUES SATISFY ──────────────────────────────────────────
 * Every value was measured with a WCAG 2.1 validator, not chosen by eye, and
 * the measured ratio is stated next to it. The constraints:
 *
 *   - Brand blue #0B57D0 is the identity in light mode.
 *   - Body text and any figure showing money reach AA (4.5:1), validated
 *     against all three text-bearing surfaces — `surface`, `background` and
 *     `surfaceMuted` — with a margin over 4.5 so device rounding cannot drop
 *     a pairing under.
 *   - Agent screens are used outdoors, so their pairings hold above 7:1.
 *   - Meaning is never carried by colour alone: every semantic tone ships a
 *     tint surface and a border, so a state can also be drawn as a shape.
 *   - A tint surface has to be distinguishable from a plain card, or a banner
 *     reads as untinted. Measured against the card, not in isolation.
 *
 * ── THE ONE RULE THAT DIFFERS BETWEEN THE RAMPS ─────────────────────────────
 * `textOnFill` is the tone that sits on a saturated fill — a primary button, a
 * success pill, a danger chip. In light mode that is WHITE. In dark mode it is
 * DARK INK, because a dark theme's tones are lightened to be legible on a dark
 * ground, and white on a lightened tone fails badly:
 *
 *   dark mode, white on `brand`     2.39:1   FAILS
 *   dark mode, ink   on `brand`     7.75:1   AA
 *
 * This is why a button must use `theme.colors.textOnBrand` and never a
 * hardcoded '#FFF'. A white label is correct in light mode and unreadable in
 * dark mode, and that is not a bug you will see unless you look for it.
 */

/**
 * The categorical hues, in the order they should be handed out.
 *
 * Adjacent entries are deliberately far apart in hue, so a grid that takes
 * them in order gets neighbouring tiles that are easy to tell apart — which is
 * the entire job of a categorical set.
 */
export const CATEGORY_HUES = [
  'blue',
  'green',
  'violet',
  'amber',
  'pink',
  'sky',
  'teal',
  'indigo',
] as const;

export type CategoryHue = (typeof CATEGORY_HUES)[number];

export type Palette = {
  /* ── surfaces ─────────────────────────────────────────────────────────── */
  background: string;
  backgroundElevated: string;
  /** Vertical wash for a full-bleed header, lightest stop first. */
  backgroundGradient: [string, string, string];
  surface: string;
  surfaceMuted: string;
  /** NON-TEXT: progress tracks, skeletons, keypad wells, disabled fills. */
  surfaceSunk: string;
  border: string;
  borderStrong: string;

  /* ── text ─────────────────────────────────────────────────────────────── */
  textPrimary: string;
  textSecondary: string;
  textMuted: string;
  /** The tone that sits ON a saturated fill. White in light, ink in dark. */
  textOnFill: string;

  /* ── brand ────────────────────────────────────────────────────────────── */
  brand: string;
  brandLight: string;
  brandDark: string;
  brandDeep: string;
  brandSurface: string;
  brandBorder: string;
  /** The full-bleed navy wash — sign-in, registration, the Home header band. */
  brandGradient: [string, string, string];
  /**
   * The vivid blue gradient for a hero object — the account card, a promo
   * banner. Brighter than `brandGradient`, which is a backdrop; this is a
   * thing sitting on the page. Carries the same on-brand tiers, and the
   * contrast script validates them against its lightest stop too.
   */
  heroGradient: [string, string, string];

  /* ── on the brand wash ────────────────────────────────────────────────── */
  onBrandPrimary: string;
  onBrandSecondary: string;
  onBrandMuted: string;
  onBrandSurface: string;
  onBrandSurfaceStrong: string;
  onBrandBorder: string;

  /* ── accent ───────────────────────────────────────────────────────────── */
  accent: string;
  accentStrong: string;
  /** Vivid fill. Takes `textOnAccentFill`, never `textOnFill`. */
  accentFill: string;
  /**
   * The tone that sits on `accentFill`.
   *
   * Dark ink in BOTH ramps — the vivid gold is light enough that white fails
   * on it either way. It needs a role of its own because the role that
   * happens to BE dark ink differs between the two: `textPrimary` in light,
   * `textOnFill` in dark. Without this, a component drawing a gold fill would
   * need a `theme.isDark` branch to pick the right one, which is the exact
   * thing these roles exist to remove.
   */
  textOnAccentFill: string;
  accentSurface: string;
  accentBorder: string;

  /* ── semantic ─────────────────────────────────────────────────────────── */
  success: string;
  successSurface: string;
  successBorder: string;
  warning: string;
  warningSurface: string;
  warningBorder: string;
  danger: string;
  dangerSurface: string;
  dangerBorder: string;
  info: string;
  infoSurface: string;
  infoBorder: string;

  /* ── categorical ──────────────────────────────────────────────────────── */
  /**
   * Decorative accents for telling categories apart — a service tile, a loan
   * type, a scheme icon.
   *
   * NOT semantic. These carry no meaning beyond "different from the one next
   * to it", and nothing should read a state off them. If a colour is saying
   * "this succeeded" or "this failed", it belongs in the semantic block above;
   * mixing the two is how an app ends up with a green that means "paid" in one
   * place and "utilities" in another.
   *
   * Each hue ships a `tone` (the icon or label) and a `surface` (the tint chip
   * behind it), because the pattern these replace was `${hue}15` — an 8% alpha
   * suffix on a raw hex. That works on a white card and vanishes on a dark
   * one, since 8% of anything over near-black is still near-black. A measured
   * pair works in both.
   */
  category: Record<CategoryHue, { tone: string; surface: string }>;

  /* ── misc ─────────────────────────────────────────────────────────────── */
  /** Scrim behind a modal or sheet. */
  overlay: string;
  /** Literal white, for the rare case that wants white regardless of theme. */
  white: string;
  /** iOS-only shadow colour; Android reads `elevation` and discards this. */
  shadow: string;
};

/* ════════════════════════════════════════════════════════════════════════════
 * LIGHT
 *
 * Content on a light ground. Ratios are stated as
 * surface / background / surfaceMuted.
 * ══════════════════════════════════════════════════════════════════════════ */

export const light: Palette = {
  /* Cool neutrals, tinted toward the brand blue. A white card on a pale
   * blue-grey ground is the whole look: the step between them is small, so
   * cards are separated by a real border and a soft lift, not by a heavy
   * tonal jump. */
  background: '#F3F6FB', //   app background — cool, barely-blue
  backgroundElevated: '#FFFFFF',
  backgroundGradient: ['#FFFFFF', '#F8FAFD', '#F3F6FB'],
  surface: '#FFFFFF', //      cards
  surfaceMuted: '#EDF1F8', // pressed rows, wells, input fills
  surfaceSunk: '#E2E8F2', //  non-text only
  border: '#DCE3EE', //       1.29:1 on a card, so it is actually visible
  borderStrong: '#C7D2E1', // 1.53:1

  textPrimary: '#0B1B3F', //   16.90 / 15.60 / 14.92 — a navy ink, not black
  textSecondary: '#4A5872', //  7.17 /  6.62 /  6.33
  textMuted: '#5C6A82', //      5.47 /  5.05 /  4.83
  textOnFill: '#FFFFFF', //     white on brand blue is 6.39:1

  brand: '#0B57D0', //        ◀ IDENTITY — 6.39 / 5.90 / 5.64
  brandLight: '#3D7BEA', //   decorative only — a gradient stop, an illustration
  brandDark: '#0845A8', //    pressed fill; white on it 8.65:1
  brandDeep: '#06296E',
  brandSurface: '#EAF1FD', // brand on it 5.63:1; separation from a card 1.14
  brandBorder: '#BBD0F6', //  1.56:1 against a card
  // Deep navy, not the brand blue. It is a BACKDROP — the sign-in screen and
  // the Home header — so it has to sit behind a blue button and white text
  // without competing with either. Every on-brand tier clears AA on it with a
  // wide margin.
  brandGradient: ['#0A2F78', '#072260', '#051843'],
  // The vivid one, for an object on the page. The lightest stop is the
  // binding case for the translucent tiers: white @0.75 on #0F4CC9 is 4.78:1.
  heroGradient: ['#0F4CC9', '#0B3FAE', '#082F86'],

  /* On the navy wash. Each tier is validated against the LIGHTEST stop of
   * both gradients, which is the worst case.
   *
   * THE TIERS DO NOT STACK. A translucent fill lightens the wash beneath it,
   * so a translucent tone on a translucent fill has less to work with.
   * Text directly on the wash may use any tier. Text on a FILL takes the
   * solid tone, always. */
  onBrandPrimary: '#FFFFFF', //                      12.42:1 wash, 7.33 hero
  onBrandSecondary: 'rgba(255, 255, 255, 0.85)', //  body-safe on both
  onBrandMuted: 'rgba(255, 255, 255, 0.75)', //      4.78:1 on the hero stop
  onBrandSurface: 'rgba(255, 255, 255, 0.12)',
  onBrandSurfaceStrong: 'rgba(255, 255, 255, 0.18)', // the ceiling for a
  //                                                    fill carrying white
  onBrandBorder: 'rgba(255, 255, 255, 0.24)',

  /* Gold, for rewards and offers. Blue and gold is a pairing a bank has used
   * for a century, and it keeps a promotional highlight visibly different
   * from a success state. */
  accent: '#876013', //       5.66 / 5.22 / 4.99 — and white-on-it 5.66:1
  accentStrong: '#6B4C0F',
  accentFill: '#E9B23C', //   ink on it 8.77:1; WHITE ON IT IS 1.93:1
  textOnAccentFill: '#0B1B3F', // 8.77:1 — the same ink as `textPrimary` here
  accentSurface: '#FEF7EA',
  accentBorder: '#EBCB8A',

  /* Each tone is the lightest — so most vivid — value that still clears 4.6:1
   * on all three text-bearing surfaces. */
  success: '#0C7645', //      5.69 / 5.25 / 5.02
  successSurface: '#E6F5ED',
  successBorder: '#9FD8BC',
  warning: '#955A00', //      5.61 / 5.18 / 4.96
  warningSurface: '#FDF3E3',
  warningBorder: '#EFCB8C',
  danger: '#C52A1F', //       5.64 / 5.20 / 4.98
  dangerSurface: '#FCEBE9',
  dangerBorder: '#EFB4AE',
  info: '#0F6CAA', //         5.61 / 5.18 / 4.95
  infoSurface: '#E8F1F8',
  infoBorder: '#A7C9E2',

  /* Ratios below are tone-on-card / tone-on-its-own-tint / tint-vs-card. */
  category: {
    blue: { tone: '#1D4ED8', surface: '#E8EDFD' }, //    6.71 / 6.03 / 1.11
    green: { tone: '#0E7A4A', surface: '#E6F5EE' }, //    5.35 / 4.82 / 1.11
    violet: { tone: '#7A35D1', surface: '#F1E9FC' }, //   5.99 / 5.19 / 1.15
    amber: { tone: '#8A5A08', surface: '#FBF2E2' }, //    5.87 / 5.03 / 1.17
    pink: { tone: '#BE185D', surface: '#FCE8F0' }, //     6.20 / 5.53 / 1.12
    sky: { tone: '#0369A1', surface: '#E4F1F9' }, //      5.62 / 5.02 / 1.12
    teal: { tone: '#036D66', surface: '#E0F3F1' }, //     5.63 / 5.00 / 1.13
    indigo: { tone: '#4F46E5', surface: '#ECEAFE' }, //   5.85 / 5.07 / 1.13
  },

  overlay: 'rgba(11, 27, 63, 0.55)',
  white: '#FFFFFF',
  // A navy shadow rather than black: on a blue-grey ground a black shadow
  // reads as dirt, a navy one reads as depth.
  shadow: '#0B1B3F',
};

/* ════════════════════════════════════════════════════════════════════════════
 * DARK
 *
 * Not the light ramp inverted. Three things genuinely change:
 *
 *   1. Every tone LIGHTENS. #0B57D0 on a dark ground is under 3:1, so the
 *      interactive brand becomes a lighter periwinkle blue and the identity
 *      is carried by hue, not by that exact hex.
 *   2. `textOnFill` becomes DARK INK. See the note at the top of this file.
 *   3. Depth stops coming from shadow. A shadow on a near-black ground is
 *      invisible, so separation is carried by the surface steps and the
 *      borders below — which is why each step is measured against its
 *      neighbour and not in isolation.
 *
 * The ground is a deep midnight navy rather than neutral black: it keeps the
 * app in the brand family, and pure #000 under light text is the classic
 * recipe for halation on an OLED panel.
 * ══════════════════════════════════════════════════════════════════════════ */

export const dark: Palette = {
  background: '#0A0F1C',
  backgroundElevated: '#121A2B',
  backgroundGradient: ['#121A2B', '#0E1523', '#0A0F1C'],
  surface: '#121A2B',
  surfaceMuted: '#1A2338',
  surfaceSunk: '#222D46', // non-text; only textPrimary 12.04, textSecondary
  //                         7.86 and brand 5.74 are legible on it
  border: '#28344E', //      1.40:1 against a card
  borderStrong: '#3A4866', // 1.90:1

  textPrimary: '#EAF1F8', //  15.26 / 16.79 / 13.74
  textSecondary: '#B6C6D6', //  9.96 / 10.96 /  8.97
  textMuted: '#93A6B9', //      6.95 /  7.65 /  6.26
  textOnFill: '#0B1420', //   ink on `brand` 7.75:1 — white would fail

  brand: '#7AA7FF', //        7.28 / 8.01 / 6.56
  brandLight: '#A6C4FF',
  brandDark: '#4F86F0', //    pressed; ink on it 5.29:1
  brandDeep: '#0A1A3D',
  brandSurface: '#15264A', // brand on it 6.25:1; separation from a card 1.17
  brandBorder: '#2A4478', //  1.82:1 against a card
  // The wash stays a saturated navy in dark mode, a step brighter than the
  // ground so the header band still reads as a band.
  brandGradient: ['#14378A', '#0E296B', '#091B4A'],
  // Lightest stop: white @0.75 on #1E4FB8 is 4.87:1.
  heroGradient: ['#1E4FB8', '#163F99', '#0F2E73'],

  onBrandPrimary: '#FFFFFF', //                      10.81 wash, 7.33 hero
  onBrandSecondary: 'rgba(255, 255, 255, 0.85)',
  onBrandMuted: 'rgba(255, 255, 255, 0.75)',
  onBrandSurface: 'rgba(255, 255, 255, 0.12)',
  onBrandSurfaceStrong: 'rgba(255, 255, 255, 0.18)',
  onBrandBorder: 'rgba(255, 255, 255, 0.24)',

  accent: '#E8BC63', //       9.77 / 10.75 / 8.80
  accentStrong: '#F0CE8A',
  accentFill: '#E9B23C', //   the same fill as light mode, and the same rule:
  //                             it takes ink, never white
  textOnAccentFill: '#0B1420', // 9.60:1. Note this is NOT `textPrimary`, which is
  //                                near-white here and only 1.69:1 on the gold —
  //                                the reason this role exists at all
  accentSurface: '#2E2817', // accent on it 8.24:1; separation 1.19
  accentBorder: '#5A4520',

  success: '#4FC98D', //      8.34 / 9.17 / 7.51
  successSurface: '#123026', // success on it 6.82:1; separation 1.22
  successBorder: '#245C40',
  warning: '#E3AC4E', //      8.51 / 9.38 / 7.66
  warningSurface: '#2E2717', // warning on it 7.24:1
  warningBorder: '#57431D',
  danger: '#F2827A', //       6.83 / 7.51 / 6.15
  dangerSurface: '#3F2228', // danger on it 5.61:1
  dangerBorder: '#5E2E34',
  info: '#63B0E3', //         7.32 / 8.06 / 6.60
  infoSurface: '#132B3E', //  info on it 6.13:1; separation 1.19
  infoBorder: '#265066',

  /* Same hues, lightened onto the dark card, each with a deepened tint. The
   * hue ORDER matches the light ramp — a category keeps its colour identity
   * across themes, so a tile a customer knows as the violet one stays violet.
   * Ratios: tone-on-card / tone-on-its-own-tint / tint-vs-card. */
  category: {
    blue: { tone: '#7FA8F5', surface: '#1A2A50' }, //     7.30 / 5.92 / 1.23
    green: { tone: '#4FC98D', surface: '#123026' }, //    8.34 / 6.82 / 1.22
    violet: { tone: '#C08CF0', surface: '#2A1F45' }, //   6.83 / 5.98 / 1.14
    amber: { tone: '#E3AC4E', surface: '#2E2717' }, //    8.51 / 7.24 / 1.19
    pink: { tone: '#F58AB4', surface: '#371F35' }, //     7.59 / 6.51 / 1.17
    sky: { tone: '#63B0E3', surface: '#132B3E' }, //      7.32 / 6.13 / 1.19
    teal: { tone: '#3FC5BC', surface: '#0F2E33' }, //     8.21 / 6.80 / 1.21
    indigo: { tone: '#A5A0FB', surface: '#22224A' }, //   7.47 / 6.46 / 1.16
  },

  // Heavier than the light scrim: the sheet beneath it is dark too, so the
  // scrim has less tonal distance to work with.
  overlay: 'rgba(3, 7, 18, 0.72)',
  white: '#FFFFFF',
  shadow: '#000000',
};