// Level tags + the two intermediate progressions added by task P-20.
// Intermediate-entry changes verified against: guitarmusictheory.com &
// Hooktheory TheoryTab & musescore.com feature ("Just the Two of Us" —
// D♭maj7–C7–Fm7 with the E♭m7–A♭7 ii–V pointing back at ♭VI, key of F minor),
// Hooktheory TheoryTab & songdna.blogspot.com & spytunes.com ("Sir Duke"
// verse B–G♯m–G–F♯7 = I–vi–♭VI7–V chromatic descent),
// docs/progression-repertoire.md §2 (modal interchange, secondary dominants,
// tritone substitution rows).
export default [
  {
    id: 'rnb-mediant-circle',
    name: 'Mediant circle (iii7–vi7–ii7–V)',
    rn: ['iii7', 'vi7', 'ii7', 'V13'],
    degrees: [4, 9, 2, 7],
    qualities: ['min7', 'min7', 'min7', 'dom7'],
    bars: [1, 1, 1, 1],
    mode: 'major',
    songs: ['September — Earth, Wind & Fire (rotation family)', 'the soul turnaround started from the iii'],
    tip: 'The 1-6-2-5 family entered from the mediant — home is implied for three bars before the V finally points at it. Neo-soul lives in that deferral.',
    level: 'foundation',
  },
  {
    id: 'rnb-6251',
    name: 'Soul 6-2-5-1 (with dominant II)',
    rn: ['vi7', 'II9', 'V9sus', 'I'],
    degrees: [9, 2, 7, 0],
    qualities: ['min7', 'dom7', 'sus4', 'maj'],
    bars: [1, 1, 1, 1],
    mode: 'major',
    songs: ["Isn't She Lovely — Stevie Wonder"],
    tip: 'The II is a secondary dominant (not the polite ii), and the V arrives as a 9sus — suspended, never quite dominant, melting into the I. Stevie\'s whole cadence language in four chords.',
    level: 'intermediate',
  },
  {
    id: 'rnb-maj7-vamp',
    name: 'Two-chord maj7 vamp (Imaj7–IVmaj7)',
    rn: ['Imaj7', 'IVmaj7'],
    degrees: [0, 5],
    qualities: ['maj7', 'maj7'],
    bars: [2, 2],
    mode: 'major',
    songs: ['Waiting in Vain — Bob Marley', "Cruisin' — Smokey Robinson (I–ii7 variant)"],
    tip: 'Two lush chords trading forever — the song is the texture. The same vamp underpins half of modern bedroom R&B; colour it differently every two bars.',
    level: 'foundation',
  },
  {
    id: 'rnb-dorian',
    name: 'Dorian vamp (i7–IV9, D\'Angelo school)',
    rn: ['i9', 'IV9'],
    degrees: [0, 5],
    qualities: ['min7', 'dom7'],
    bars: [1, 1],
    mode: 'dorian',
    songs: ["Spanish Joint — D'Angelo", "Didn't Cha Know — Erykah Badu (i–iv minor variant)", "Brown Sugar — D'Angelo (E Dorian loop)"],
    tip: 'The IV9 carries the raised 6th that makes it Dorian — the same pair as the funk vamp, slowed to 70 BPM and dragged behind the beat.',
    level: 'foundation',
  },
  {
    id: 'rnb-gospel-amen',
    name: 'Gospel Amen (IV–iv–I)',
    rn: ['IVmaj7', 'iv6', 'Imaj7'],
    degrees: [5, 5, 0],
    qualities: ['maj7', 'min6', 'maj7'],
    bars: [1, 1, 2],
    mode: 'major',
    songs: ['the gospel "Amen" cadence', 'countless soul ballad turnarounds (borrowed iv)'],
    tip: 'The IV turns minor on its way home — borrowed from the parallel minor, the single most-borrowed chord in soul. One semitone (the 3rd of the IV falling) does all the work.',
    level: 'intermediate',
  },
  {
    id: 'rnb-justthetwo',
    name: 'Just-the-Two-of-Us loop (♭VI–V–i + ii–V of ♭VI)',
    rn: ['♭VImaj7', 'V7', 'i7', '♭vii7', '♭III7'],
    degrees: [8, 7, 0, 10, 3],
    qualities: ['maj7', 'dom7', 'min7', 'min7', 'dom7'],
    bars: [1, 1, 2, 1, 1],
    mode: 'minor',
    songs: ['Just the Two of Us — Grover Washington Jr. & Bill Withers', 'a smooth-soul/90s-R&B staple loop'],
    tip: 'A minor loop that spends most of its time away from home: ♭VI–V–i falls in half steps, then the ♭vii–♭III7 is a ii–V aimed back at ♭VI, not at i. Hearing ii–Vs that target chords other than the tonic is the door out of diatonic playing — in the original the last two chords share one bar.',
    level: 'intermediate',
  },
  {
    id: 'rnb-chromatic-vi',
    name: 'Chromatic soul descent (I–vi–♭VI7–V)',
    rn: ['I', 'vi7', '♭VI7', 'V7'],
    degrees: [0, 9, 8, 7],
    qualities: ['maj', 'min7', 'dom7', 'dom7'],
    bars: [1, 1, 1, 1],
    mode: 'major',
    songs: ['Sir Duke — Stevie Wonder (verse)'],
    tip: 'One swapped chord makes it: where the diatonic loop would repeat vi or move to IV, the ♭VI7 (borrowed from the parallel minor) slides the bass down 6–♭6–5 in half steps. It doubles as a tritone sub of II7 (V/V) — either way the whole chord planes down a semitone into V.',
    level: 'intermediate',
  },
]
