import { afterEach, describe, expect, it, vi } from 'vitest'

// `theme.js` reads `process.env` at module-load to compute DEFAULT_THEME,
// and `fromSkin` closes over DEFAULT_THEME.  A developer shell with
// HERMES_TUI_THEME=light (or HERMES_TUI_BACKGROUND set to something
// bright) would flip the base and turn these assertions into a local-
// only failure.  We sterilize the relevant env vars + dynamically
// import the module fresh so EVERY symbol that closes over the env
// (DEFAULT_THEME, DARK_THEME, LIGHT_THEME, fromSkin) is loaded against
// a known-empty environment.
//
// `detectLightMode` takes env as an explicit arg, so it's safe to import
// statically — but we stay consistent and dynamic-import it too.
const RELEVANT_ENV = [
  'HERMES_TUI_LIGHT',
  'HERMES_TUI_THEME',
  'HERMES_TUI_BACKGROUND',
  'COLORFGBG',
  'COLORTERM',
  'TERM_PROGRAM'
] as const

async function importThemeWithEnv(env: Partial<Record<(typeof RELEVANT_ENV)[number], string>> = {}) {
  for (const key of RELEVANT_ENV) {
    vi.stubEnv(key, env[key] ?? '')
  }

  vi.resetModules()

  return import('../theme.js')
}

async function importThemeWithCleanEnv() {
  return importThemeWithEnv()
}

afterEach(() => {
  vi.unstubAllEnvs()
  vi.resetModules()
})

describe('DEFAULT_THEME', () => {
  it('has brand defaults', async () => {
    const { DEFAULT_THEME } = await importThemeWithCleanEnv()

    expect(DEFAULT_THEME.brand.name).toBe('Hermes Agent')
    expect(DEFAULT_THEME.brand.prompt).toBe('❯')
    expect(DEFAULT_THEME.brand.tool).toBe('┊')
  })

  it('has color palette', async () => {
    const { DEFAULT_THEME } = await importThemeWithCleanEnv()

    expect(DEFAULT_THEME.color.primary).toBe('#FFD700')
    expect(DEFAULT_THEME.color.error).toBe('#ef5350')
  })
})

describe('LIGHT_THEME', () => {
  it('avoids bright-yellow accents unreadable on white backgrounds (#11300)', async () => {
    const { LIGHT_THEME } = await importThemeWithCleanEnv()

    expect(LIGHT_THEME.color.primary).not.toBe('#FFD700')
    expect(LIGHT_THEME.color.accent).not.toBe('#FFBF00')
    expect(LIGHT_THEME.color.muted).not.toBe('#B8860B')
    expect(LIGHT_THEME.color.statusWarn).not.toBe('#FFD700')
  })

  it('keeps the same shape as DARK_THEME', async () => {
    const { DARK_THEME, LIGHT_THEME } = await importThemeWithCleanEnv()

    expect(Object.keys(LIGHT_THEME.color).sort()).toEqual(Object.keys(DARK_THEME.color).sort())
    expect(LIGHT_THEME.brand).toEqual(DARK_THEME.brand)
  })
})

describe('DEFAULT_THEME aliasing', () => {
  it('defaults to DARK_THEME when nothing signals light', async () => {
    const { DEFAULT_THEME, DARK_THEME: DARK } = await importThemeWithCleanEnv()

    expect(DEFAULT_THEME).toBe(DARK)
  })
})

describe('detectLightMode', () => {
  it('returns false on empty env', async () => {
    const { detectLightMode } = await importThemeWithCleanEnv()

    expect(detectLightMode({})).toBe(false)
  })

  it('defaults Apple Terminal to light when no stronger signal is present', async () => {
    const { detectLightMode } = await importThemeWithCleanEnv()

    expect(detectLightMode({ TERM_PROGRAM: 'Apple_Terminal' })).toBe(true)
  })

  it('honors HERMES_TUI_LIGHT on/off', async () => {
    const { detectLightMode } = await importThemeWithCleanEnv()

    expect(detectLightMode({ HERMES_TUI_LIGHT: '1' })).toBe(true)
    expect(detectLightMode({ HERMES_TUI_LIGHT: 'true' })).toBe(true)
    expect(detectLightMode({ HERMES_TUI_LIGHT: 'on' })).toBe(true)
    expect(detectLightMode({ HERMES_TUI_LIGHT: '0' })).toBe(false)
    expect(detectLightMode({ HERMES_TUI_LIGHT: 'off' })).toBe(false)
  })

  it('sniffs COLORFGBG bg slots 7 and 15 as light (#11300)', async () => {
    const { detectLightMode } = await importThemeWithCleanEnv()

    expect(detectLightMode({ COLORFGBG: '0;15' })).toBe(true)
    expect(detectLightMode({ COLORFGBG: '0;default;15' })).toBe(true)
    expect(detectLightMode({ COLORFGBG: '0;7' })).toBe(true)
    expect(detectLightMode({ COLORFGBG: '15;0' })).toBe(false)
    expect(detectLightMode({ COLORFGBG: '7;default;0' })).toBe(false)
  })

  it('falls through on malformed COLORFGBG with empty/non-numeric trailing field', async () => {
    const { detectLightMode } = await importThemeWithCleanEnv()
    // `Number('')` is 0, so `'15;'` would have been read as bg=0
    // (authoritative dark) and incorrectly blocked TERM_PROGRAM.
    // The strict /^\d+$/ guard makes these fall through instead.
    const allowList = new Set(['Apple_Terminal'])

    expect(detectLightMode({ COLORFGBG: '15;', TERM_PROGRAM: 'Apple_Terminal' }, allowList)).toBe(true)
    expect(detectLightMode({ COLORFGBG: 'default;default', TERM_PROGRAM: 'Apple_Terminal' }, allowList)).toBe(true)
    // Without an allow-list match, fall-through still defaults to dark.
    expect(detectLightMode({ COLORFGBG: '15;' })).toBe(false)
  })

  it('lets HERMES_TUI_LIGHT=0 override a light COLORFGBG', async () => {
    const { detectLightMode } = await importThemeWithCleanEnv()

    expect(detectLightMode({ COLORFGBG: '0;15', HERMES_TUI_LIGHT: '0' })).toBe(false)
  })

  it('honors HERMES_TUI_THEME=light/dark as a symmetric explicit override', async () => {
    const { detectLightMode } = await importThemeWithCleanEnv()

    expect(detectLightMode({ HERMES_TUI_THEME: 'light' })).toBe(true)
    expect(detectLightMode({ HERMES_TUI_THEME: 'dark' })).toBe(false)
    expect(detectLightMode({ COLORFGBG: '0;15', HERMES_TUI_THEME: 'dark' })).toBe(false)
    expect(detectLightMode({ COLORFGBG: '15;0', HERMES_TUI_THEME: 'light' })).toBe(true)
  })

  it('uses HERMES_TUI_BACKGROUND luminance when COLORFGBG is missing', async () => {
    const { detectLightMode } = await importThemeWithCleanEnv()

    expect(detectLightMode({ HERMES_TUI_BACKGROUND: '#ffffff' })).toBe(true)
    expect(detectLightMode({ HERMES_TUI_BACKGROUND: '#000000' })).toBe(false)
    expect(detectLightMode({ HERMES_TUI_BACKGROUND: '#1e1e1e' })).toBe(false)
    // Three-char hex normalises like CSS.
    expect(detectLightMode({ HERMES_TUI_BACKGROUND: '#fff' })).toBe(true)
    // Garbage falls through to the default-dark path.
    expect(detectLightMode({ HERMES_TUI_BACKGROUND: 'not-a-colour' })).toBe(false)
  })

  it('rejects partially-invalid hex instead of silently truncating', async () => {
    const { detectLightMode } = await importThemeWithCleanEnv()
    // `parseInt('fffgff'.slice(2,4), 16)` would return 15 — the strict
    // regex must reject these inputs so they fall through to default-
    // dark instead of producing a false-positive light reading.
    expect(detectLightMode({ HERMES_TUI_BACKGROUND: '#fffgff' })).toBe(false)
    expect(detectLightMode({ HERMES_TUI_BACKGROUND: 'ffggff' })).toBe(false)
    expect(detectLightMode({ HERMES_TUI_BACKGROUND: '#xyz' })).toBe(false)
    // Wrong length also rejected (no implicit padding/truncation).
    expect(detectLightMode({ HERMES_TUI_BACKGROUND: '#fffff' })).toBe(false)
    expect(detectLightMode({ HERMES_TUI_BACKGROUND: '#fffffff' })).toBe(false)
  })

  it('treats COLORFGBG as authoritative when present so it dominates the TERM_PROGRAM allow-list', async () => {
    const { detectLightMode } = await importThemeWithCleanEnv()
    // Injecting the allow-list keeps this precedence rule explicit even if
    // production defaults change.
    const allowList = new Set(['Apple_Terminal'])

    // Sanity: the allow-list alone WOULD turn this terminal light.
    expect(detectLightMode({ TERM_PROGRAM: 'Apple_Terminal' }, allowList)).toBe(true)

    // Dark COLORFGBG must beat the allow-list.
    expect(detectLightMode({ COLORFGBG: '15;0', TERM_PROGRAM: 'Apple_Terminal' }, allowList)).toBe(false)
  })
})

describe('fromSkin', () => {
  // `fromSkin` closes over DEFAULT_THEME (which is env-derived), so we
  // must dynamic-import it after sterilizing env — otherwise an ambient
  // HERMES_TUI_THEME=light would flip the base palette and make these
  // assertions order-dependent on the developer's shell.

  it('overrides banner colors', async () => {
    const { fromSkin } = await importThemeWithCleanEnv()

    expect(fromSkin({ banner_title: '#FF0000' }, {}).color.primary).toBe('#FF0000')
  })

  it('preserves unset colors', async () => {
    const { DEFAULT_THEME, fromSkin } = await importThemeWithCleanEnv()

    expect(fromSkin({ banner_title: '#FF0000' }, {}).color.accent).toBe(DEFAULT_THEME.color.accent)
  })

  it('derives completion current background from resolved completion background (polarity-compatible)', async () => {
    // Light terminal + light-authored menu fill: the skin's fill is honored
    // and the current-row derivation mixes off it.
    const { fromSkin } = await importThemeWithEnv({ HERMES_TUI_BACKGROUND: '#ffffff' })

    const theme = fromSkin({ banner_accent: '#000000', completion_menu_bg: '#ffffff' }, {})

    expect(theme.color.completionBg).toBe('#ffffff')
    // Active row = authored surface mixed toward the accent (ladder knob).
    expect(theme.color.completionCurrentBg).toBe('#c7c7c7')
  })

  it('rejects wrong-polarity fills even when skin-authored (terminal owns the canvas)', async () => {
    // Dark terminal + white menu fill: unlike the desktop app, the TUI cannot
    // paint its own canvas, so cross-polarity fills fall back to the derived
    // ladder values, which are mixed from the real background and therefore
    // polarity-correct by construction.
    const { fromSkin } = await importThemeWithCleanEnv()

    const theme = fromSkin({ banner_accent: '#000000', completion_menu_bg: '#ffffff' }, {})

    expect(luminance(theme.color.completionBg)).toBeLessThanOrEqual(0.35)
    expect(luminance(theme.color.completionCurrentBg)).toBeLessThanOrEqual(0.35)
  })

  it('uses active completion color as the selection highlight fallback', async () => {
    const { fromSkin } = await importThemeWithCleanEnv()

    const theme = fromSkin({ completion_menu_current_bg: '#123456' }, {})

    expect(theme.color.selectionBg).toBe('#123456')
  })

  it('maps completion meta background colors from skins', async () => {
    const { fromSkin } = await importThemeWithCleanEnv()

    const theme = fromSkin(
      {
        completion_menu_meta_bg: '#111111',
        completion_menu_meta_current_bg: '#222222'
      },
      {}
    )

    expect(theme.color.completionMetaBg).toBe('#111111')
    expect(theme.color.completionMetaCurrentBg).toBe('#222222')
  })

  it('lets selection_bg override completion highlight colors', async () => {
    const { fromSkin } = await importThemeWithCleanEnv()

    const theme = fromSkin({ completion_menu_current_bg: '#123456', selection_bg: '#654321' }, {})

    expect(theme.color.selectionBg).toBe('#654321')
  })

  it('overrides branding', async () => {
    const { fromSkin } = await importThemeWithCleanEnv()
    const { brand } = fromSkin({}, { agent_name: 'TestBot', prompt_symbol: '$' })

    expect(brand.name).toBe('TestBot')
    expect(brand.prompt).toBe('$')
  })

  it('normalizes skin prompt symbols to trimmed single-line text', async () => {
    const { DEFAULT_THEME, fromSkin } = await importThemeWithCleanEnv()

    expect(fromSkin({}, { prompt_symbol: ' ⚔ ❯ \n' }).brand.prompt).toBe('⚔ ❯')
    expect(fromSkin({}, { prompt_symbol: ' Ψ > \n' }).brand.prompt).toBe('Ψ >')
    expect(fromSkin({}, { prompt_symbol: '\n\t' }).brand.prompt).toBe(DEFAULT_THEME.brand.prompt)
  })

  it('defaults for empty skin', async () => {
    const { DEFAULT_THEME, fromSkin } = await importThemeWithCleanEnv()

    expect(fromSkin({}, {}).color).toEqual(DEFAULT_THEME.color)
    expect(fromSkin({}, {}).brand.icon).toBe(DEFAULT_THEME.brand.icon)
  })

  it('normalizes non-banner foregrounds on light Apple Terminal', async () => {
    const { fromSkin } = await importThemeWithEnv({ TERM_PROGRAM: 'Apple_Terminal' })

    const theme = fromSkin(
      {
        banner_accent: '#FFBF00',
        banner_border: '#CD7F32',
        banner_dim: '#B8860B',
        banner_text: '#FFF8DC',
        banner_title: '#FFD700',
        prompt: '#FFF8DC'
      },
      {}
    )

    expect(theme.color.primary).toBe('#FFD700')
    expect(theme.color.accent).toBe('#FFBF00')
    expect(theme.color.border).toBe('#CD7F32')
    expect(theme.color.muted).toBe('ansi256(245)')
    expect(theme.color.text).toBe('ansi256(136)')
    expect(theme.color.prompt).toBe('ansi256(136)')
  })

  // ── A skin that authors a background OWNS its polarity ──────────────
  // The TUI paints the terminal with the skin's background (OSC-11), so
  // every adaptation pass must run against the skin's canvas, not the host
  // profile the skin just covered. The real-world failure: a pure-black
  // skin on light-mode Apple Terminal got its text ansi256-bucketed for a
  // light background that no longer exists — invisible on the painted black.

  it('a dark-background skin on light Apple Terminal keeps its truecolor text (no light-mode bucketing)', async () => {
    const { fromSkin } = await importThemeWithEnv({ TERM_PROGRAM: 'Apple_Terminal' })

    const theme = fromSkin({ background: '#000000', ui_accent: '#ff9e18', ui_text: '#ffa726' }, {})

    expect(theme.color.text).toBe('#ffa726')
    expect(theme.color.prompt).not.toMatch(/^ansi256/)
  })

  it('a skin background outranks the cached host background for adaptation and tone derivation', async () => {
    const { fromSkin } = await importThemeWithEnv({ HERMES_TUI_BACKGROUND: '#ffffff' })

    const theme = fromSkin({ background: '#000000', ui_text: '#ffa726' }, {})

    // Text is not contrast-lifted toward a white host it painted over…
    expect(theme.color.text).toBe('#ffa726')
    // …and derived fills mix against the skin's black, not the host's white.
    expect(luminance(theme.color.completionBg)).toBeLessThanOrEqual(0.35)
    expect(luminance(theme.color.statusBg)).toBeLessThanOrEqual(0.35)
  })

  it('skinIsLight: the authored background decides; host detection only when absent', async () => {
    const { skinIsLight } = await importThemeWithEnv({ HERMES_TUI_BACKGROUND: '#ffffff' })

    expect(skinIsLight({ background: '#000000' })).toBe(false)
    expect(skinIsLight({ background: '#f5f5f5' })).toBe(true)
    expect(skinIsLight({})).toBe(true) // no canvas of its own → host polarity
  })

  it('keeps truecolor light Apple Terminal in truecolor (adapting, not ansi256-bucketing)', async () => {
    const { contrastRatio, fromSkin } = await importThemeWithEnv({
      COLORTERM: 'truecolor',
      TERM_PROGRAM: 'Apple_Terminal'
    })

    const theme = fromSkin({ banner_text: '#FFF8DC' }, {})

    // No ansi256 bucketing on truecolor terminals — a truly invisible cream
    // (1.08:1 on white) still gets the display shim's gentle light-mode rescue
    // (floor 1.18: enough to make near-white text appear, not enough to crush
    // the vivid golds into mud).
    expect(theme.color.text).toMatch(/^#[0-9a-f]{6}$/i)
    expect(contrastRatio(theme.color.text, '#ffffff')!).toBeGreaterThanOrEqual(1.18)
  })

  it('normalizes Apple Terminal names before matching', async () => {
    const { fromSkin } = await importThemeWithEnv({ TERM_PROGRAM: ' Apple_Terminal ' })
    const theme = fromSkin({ banner_text: '#FFF8DC' }, {})

    expect(theme.color.text).toBe('ansi256(136)')
  })

  it('passes banner logo/hero', async () => {
    const { fromSkin } = await importThemeWithCleanEnv()

    expect(fromSkin({}, {}, 'LOGO', 'HERO').bannerLogo).toBe('LOGO')
    expect(fromSkin({}, {}, 'LOGO', 'HERO').bannerHero).toBe('HERO')
  })

  it('maps ui_ color keys + cascades to status', async () => {
    const { fromSkin } = await importThemeWithCleanEnv()
    const { color } = fromSkin({ ui_ok: '#008000' }, {})

    // The exact value may be contrast-lifted against the background; the
    // contract is the cascade (ok drives statusGood) and the hue surviving.
    expect(color.statusGood).toBe(color.ok)
    expect(color.ok).toMatch(/^#[0-9a-f]{6}$/i)
    expect(luminance(color.ok)).toBeGreaterThan(0)
  })
})

// Rec. 709-ish relative luminance, local to the test so assertions are
// independent of the implementation under test.
const luminance = (hex: string): number => {
  const n = parseInt(hex.replace('#', ''), 16)

  const channel = (v: number) => {
    const c = v / 255

    return c <= 0.03928 ? c / 12.92 : ((c + 0.055) / 1.055) ** 2.4
  }

  return 0.2126 * channel((n >> 16) & 0xff) + 0.7152 * channel((n >> 8) & 0xff) + 0.0722 * channel(n & 0xff)
}

// The bundled slate skin's actual color block — dark-authored (pale pastels,
// no completion/selection backgrounds defined).
const SLATE_COLORS = {
  banner_accent: '#8EA8FF',
  banner_border: '#4169e1',
  banner_dim: '#4b5563',
  banner_text: '#c9d1d9',
  banner_title: '#7eb8f6',
  prompt: '#c9d1d9',
  session_border: '#4b5563',
  session_label: '#7eb8f6',
  ui_accent: '#7eb8f6',
  ui_error: '#F7A072',
  ui_label: '#8EA8FF',
  ui_ok: '#63D0A6',
  ui_warn: '#e6a855'
}

// Max per-channel deviation between two hexes.
const channelDelta = (a: string, b: string) => {
  const pa = parseInt(a.replace('#', ''), 16)
  const pb = parseInt(b.replace('#', ''), 16)

  return Math.max(
    Math.abs(((pa >> 16) & 0xff) - ((pb >> 16) & 0xff)),
    Math.abs(((pa >> 8) & 0xff) - ((pb >> 8) & 0xff)),
    Math.abs((pa & 0xff) - (pb & 0xff))
  )
}

describe('derived tone ladder', () => {
  it('reproduces the original hand-tuned tones from seeds (reverse-engineered knobs)', async () => {
    // The ladder's knobs were grid-search fitted so the MATH lands on the
    // pre-refactor hand-tuned literals. Contract: every derived tone stays
    // within a-few-RGB-units of the original (imperceptible), so knob edits
    // that drift the classic look fail here instead of shipping as vibes.
    const dark = await importThemeWithCleanEnv()
    const light = await importThemeWithEnv({ HERMES_TUI_BACKGROUND: '#ffffff' })

    const cases: Array<[string, string, string]> = [
      [dark.DARK_THEME.color.muted, '#CC9B1F', 'dark muted'],
      [dark.DARK_THEME.color.label, '#DAA520', 'dark label'],
      [dark.DARK_THEME.color.statusFg, '#C0C0C0', 'dark statusFg'],
      [dark.DARK_THEME.color.completionBg, '#1a1a2e', 'dark surface'],
      [dark.DARK_THEME.color.completionCurrentBg, '#333355', 'dark chip'],
      [dark.DARK_THEME.color.selectionBg, '#3a3a55', 'dark selection'],
      // Light canon = liftForContrast(dark literal, white, 4.5): the exact
      // colors xterm's minimumContrastRatio rendered on light hosts.
      [light.LIGHT_THEME.color.muted, '#946C08', 'light muted'],
      [light.LIGHT_THEME.color.statusFg, '#6F6F6F', 'light statusFg'],
      [light.LIGHT_THEME.color.completionBg, '#F5F5F5', 'light surface'],
      [light.LIGHT_THEME.color.completionCurrentBg, '#e0d1bf', 'light chip'],
      [light.LIGHT_THEME.color.selectionBg, '#D4E4F7', 'light selection']
    ]

    for (const [got, original, label] of cases) {
      expect(channelDelta(got, original), `${label}: ${got} vs original ${original}`).toBeLessThanOrEqual(8)
    }
  })

  it('derives dim/secondary tones from the skin identity, not another palette', async () => {
    const { fromSkin } = await importThemeWithCleanEnv()

    // A seeds-only skin (no dim/label/menu keys authored at all).
    const { color } = fromSkin({ banner_accent: '#DD4A3A', banner_text: '#F1E6CF', banner_title: '#C7A96B' }, {})

    // Muted recedes from THIS skin's text toward the background with an
    // accent tint — a red-family derivative, never another skin's gold.
    expect(color.muted).not.toBe(color.text)
    expect(luminance(color.muted)).toBeLessThan(luminance(color.text))

    const rgb = (hex: string) => [1, 3, 5].map(i => parseInt(hex.slice(i, i + 2), 16))
    const [mr, , mb] = rgb(color.muted)

    expect(mr).toBeGreaterThan(mb!)

    // The active-row chip is the surface tinted with the skin accent —
    // redder than the plain surface.
    const [sr] = rgb(color.completionBg)

    expect(rgb(color.completionCurrentBg)[0]).toBeGreaterThan(sr!)
  })

  it('authored tones still override the ladder', async () => {
    const { fromSkin } = await importThemeWithCleanEnv()
    const { color } = fromSkin({ banner_dim: '#AA8844', banner_text: '#F1E6CF' }, {})

    expect(color.muted).toBe('#AA8844')
    expect(color.sessionLabel).toBe('#AA8844')
  })
})

describe('background-aware adaptation (OSC-11 light terminals)', () => {
  it('renders a dark-authored skin on light like minimumContrastRatio hosts do (the standardized look)', async () => {
    const { contrastRatio, fromSkin } = await importThemeWithEnv({ HERMES_TUI_BACKGROUND: '#ffffff' })
    const { color } = fromSkin(SLATE_COLORS, {})

    // The authored palette IS the design: slate's airy pastels (~1.5:1) pass
    // through BYTE-IDENTICAL — that receded look is the standardized
    // rendering, not a washout to fix.
    expect(color.text.toLowerCase()).toBe('#c9d1d9')
    expect(color.accent.toLowerCase()).toBe('#7eb8f6')
    expect(color.muted.toLowerCase()).toBe('#4b5563')

    // Light mode renders the authored palette essentially RAW: a transparent
    // terminal (the common Cursor case) applies no contrast lift of its own,
    // and the beloved classic look is the vivid palette, not a WCAG-darkened
    // one. Foregrounds only clear the near-invisible floor (1.18).
    for (const key of ['text', 'prompt', 'accent', 'label', 'primary', 'muted', 'border'] as const) {
      expect(contrastRatio(color[key], '#ffffff'), `${key} ${color[key]}`).toBeGreaterThanOrEqual(1.18)
    }

    // Semantic alert colors carry meaning — firmer floor, still gentle on light.
    for (const key of ['ok', 'error', 'warn', 'statusGood', 'statusCritical'] as const) {
      expect(contrastRatio(color[key], '#ffffff'), `${key} ${color[key]}`).toBeGreaterThanOrEqual(1.6)
    }

    // Background roles the skin never defined must be light-polarity fills,
    // not the dark base's navy.
    for (const key of ['completionBg', 'completionCurrentBg', 'statusBg', 'selectionBg'] as const) {
      expect(luminance(color[key]), `${key} ${color[key]}`).toBeGreaterThanOrEqual(0.4)
    }
  })

  it('rescues near-invisible colors with a hue-preserving multiplicative lift', async () => {
    const { contrastRatio, fromSkin } = await importThemeWithEnv({ HERMES_TUI_BACKGROUND: '#ffffff' })
    // The default dark cream (#FFF8DC, 1.08:1 on white) is genuinely invisible.
    const { color } = fromSkin({ banner_text: '#FFF8DC' }, {})

    expect(color.text.toLowerCase()).not.toBe('#fff8dc')
    expect(contrastRatio(color.text, '#ffffff')!).toBeGreaterThanOrEqual(1.18)

    // Multiplicative lift preserves channel ordering (warm stays warm).
    const [r, g, b] = [1, 3, 5].map(i => parseInt(color.text.slice(i, i + 2), 16))

    expect(r).toBeGreaterThanOrEqual(g!)
    expect(g).toBeGreaterThanOrEqual(b!)
  })

  it('leaves the same skin untouched on a dark background', async () => {
    const { fromSkin } = await importThemeWithEnv({ HERMES_TUI_BACKGROUND: '#1e1e2e' })
    const { color } = fromSkin(SLATE_COLORS, {})

    expect(color.text).toBe('#c9d1d9')
    expect(color.accent).toBe('#7eb8f6')
    expect(luminance(color.completionBg)).toBeLessThanOrEqual(0.35)
  })

  it('empty skin on a light background resolves to the light base palette', async () => {
    const { fromSkin, LIGHT_THEME } = await importThemeWithEnv({ HERMES_TUI_BACKGROUND: '#ffffff' })

    expect(fromSkin({}, {}).color).toEqual(LIGHT_THEME.color)
  })

  it('base palettes are fixed points of the adaptation', async () => {
    const dark = await importThemeWithCleanEnv()

    expect(dark.fromSkin({}, {}).color).toEqual(dark.DARK_THEME.color)

    const light = await importThemeWithEnv({ HERMES_TUI_BACKGROUND: '#ffffff' })

    expect(light.fromSkin({}, {}).color).toEqual(light.LIGHT_THEME.color)
  })

  it('defaultThemeForCurrentBackground follows a late HERMES_TUI_BACKGROUND write', async () => {
    const { DARK_THEME, DEFAULT_THEME, defaultThemeForCurrentBackground, LIGHT_THEME } = await importThemeWithCleanEnv()

    // Module loaded dark (clean env)…
    expect(DEFAULT_THEME.color.completionBg).toBe(DARK_THEME.color.completionBg)
    expect(luminance(DEFAULT_THEME.color.completionBg)).toBeLessThanOrEqual(0.35)

    // …then the OSC-11 answer lands and is cached into the env slot.
    expect(defaultThemeForCurrentBackground({ HERMES_TUI_BACKGROUND: '#ffffff' }).color).toEqual(LIGHT_THEME.color)
  })

  it('gives tool + thinking their own keys, defaulting to accent + muted', async () => {
    const { fromSkin } = await importThemeWithCleanEnv()

    // Independent override: recoloring tool/thinking doesn't leak into accent.
    // (Values flow through #20379's contrast adaptation, so assert the
    //  independence contract, not raw pre-adaptation hexes.)
    const themed = fromSkin({ ui_accent: '#3aa0ff', ui_tool: '#ff0000', ui_thinking: '#00ff00' }, {})
    const baseline = fromSkin({ ui_accent: '#3aa0ff' }, {})
    expect(themed.color.tool).toBe('#ff0000')
    expect(themed.color.thinking).toBe('#00ff00')
    expect(themed.color.tool).not.toBe(themed.color.accent)
    expect(themed.color.accent).toBe(baseline.color.accent) // override didn't touch accent

    // Default: tool follows accent, thinking follows muted — same source →
    // identical after adaptation.
    const fallback = fromSkin({ ui_accent: '#3aa0ff', banner_dim: '#8a8a8a' }, {})
    expect(fallback.color.tool).toBe(fallback.color.accent)
    expect(fallback.color.thinking).toBe(fallback.color.muted)
  })

  it('gives code syntax its own keys, defaulting to accent/text/border/muted', async () => {
    const { fromSkin } = await importThemeWithCleanEnv()

    const themed = fromSkin(
      { syntax_string: '#aa0000', syntax_number: '#00aa00', syntax_keyword: '#0000aa', syntax_comment: '#888888' },
      {}
    )

    expect(themed.color.syntaxString).toBe('#aa0000')
    expect(themed.color.syntaxNumber).toBe('#00aa00')
    expect(themed.color.syntaxKeyword).toBe('#0000aa')
    expect(themed.color.syntaxComment).toBe('#888888')

    const fallback = fromSkin({ ui_accent: '#abcdef' }, {})
    expect(fallback.color.syntaxString).toBe('#abcdef') // string follows accent
  })

  it('lets skins override diff colors', async () => {
    const { fromSkin } = await importThemeWithCleanEnv()

    const { color } = fromSkin(
      { diff_added: '#0a0', diff_removed: '#a00', diff_added_word: '#0f0', diff_removed_word: '#f00' },
      {}
    )

    expect(color.diffAdded).toBe('#0a0')
    expect(color.diffRemoved).toBe('#a00')
    expect(color.diffAddedWord).toBe('#0f0')
    expect(color.diffRemovedWord).toBe('#f00')
  })

  it('maps the status bar from skin status_bar_* keys', async () => {
    const { fromSkin } = await importThemeWithCleanEnv()

    const { color } = fromSkin(
      {
        status_bar_bg: '#101020',
        status_bar_text: '#e0e0e0',
        status_bar_bad: '#ff8800',
        status_bar_critical: '#ff0000'
      },
      {}
    )

    expect(color.statusBg).toBe('#101020')
    expect(color.statusFg).toBe('#e0e0e0')
    expect(color.statusBad).toBe('#ff8800')
    expect(color.statusCritical).toBe('#ff0000')
  })

  it('falls the status bar back to background + semantic colors', async () => {
    const { fromSkin } = await importThemeWithCleanEnv()
    const { color } = fromSkin({ background: '#0a0a0a', banner_text: '#fafafa', ui_error: '#dd2222' }, {})

    // background paints the surface → status/completion bg; banner_text → status
    // fg; ui_error → critical. Semantic hues flow through contrast adaptation,
    // so `statusCritical` is asserted to track `ui_error` identically rather
    // than pinning an adapted hex.
    expect(color.statusBg).toBe('#0a0a0a')
    expect(color.completionBg).toBe('#0a0a0a')
    expect(color.statusFg).toBe('#fafafa')
    expect(color.statusCritical).toBe(fromSkin({ ui_error: '#dd2222' }, {}).color.error)
  })
})