# Jazz Half-Time Shuffle — Rosanna / Purdie Shuffle style
# Reference: "Rosanna" (Toto, 1982, Jeff Porcaro), Bernard Purdie, arXiv 2411.06892
# The defining features: (1) snare hits ONLY on beat 3 — the half-time feel,
# (2) dense ghost notes fill the gaps, (3) hi-hat plays a shuffle pattern (beat + swing "trip"),
# (4) kick plays a Bo Diddley hemiola figure that crosses the beat.
# With swing_hard enabled, odd steps (3, 7, 11, 15) are delayed ~0.085 beats, producing
# the shuffle triplet feel: long gap (beat to trip) then short gap (trip to next beat).
# GM notes: 36=kick, 38=snare+ghosts, 42=HH, 48=hi tom (fills), 49=crash

#
# ── Step grid notation ────────────────────────────────────────────────────────
# Each character in a step grid represents one subdivision of the bar.
# Resolution controls how many steps per bar (16 = 16th notes in 4/4; 12 = 16th notes in 6/8).
#
#   X   Strong accent  — velocity = base_velocity × 1.00  (full hit / downbeat)
#   x   Medium accent  — velocity = base_velocity × 0.75  (firm stroke / upbeat)
#   o   Soft hit       — velocity = base_velocity × 0.55  (brush / light touch)
#   g   Ghost note     — velocity = base_velocity × 0.28  (barely audible, mostly felt)
#   .   Rest           — no note fired at this step
#
# Beat positions — 4/4 at resolution 16 (one char per 16th note):
#   pos  0  1  2  3  4  5  6  7  8  9 10 11 12 13 14 15
#        1  e1 +1 a1  2  e2 +2 a2  3  e3 +3 a3  4  e4 +4 a4
#   (1/+/2/+/3/+/4/+ = quarter beats; e = "e of"; a = "and-a of")
#
# Beat positions — 6/8 at resolution 12 (one char per 16th note):
#   pos  0  1  2  3  4  5  6  7  8  9 10 11
#        C1 .  e1 .  a1 .  C2 .  e2 .  a2 .
#   (C1/C2 = compound beat downbeats; each compound beat = 3 eighth notes = 6 steps)
#
# Swing / feel: the 'feel' field shifts odd-indexed steps (1,3,5,7…) forward in time.
#   straight   — no shift (all steps exactly on the grid)
#   swing_soft — odd steps delayed ~16 % of a step (light swing)
#   swing_hard — odd steps delayed ~34 % of a step (jazz/shuffle triplet feel)
#   laid_back  — same as straight with slower humanisation envelope
# ─────────────────────────────────────────────────────────────────────────────

name: Half-Time Shuffle
family: jazz
bpm_range: [70, 130]
time_signature: [4, 4]
resolution: 16
feel: swing_hard

instruments:
  kick:  { note: 36, base_velocity: 100, velocity_range: 12, timing_jitter: 0.018, duration_beats: 0.14 }
  snare: { note: 38, base_velocity: 100, velocity_range: 16, timing_jitter: 0.020, duration_beats: 0.12 }
  hihat: { note: 42, base_velocity: 82,  velocity_range: 12, timing_jitter: 0.018, duration_beats: 0.08 }
  tom_hi: { note: 48, base_velocity: 90, velocity_range: 15, timing_jitter: 0.018, duration_beats: 0.10 }
  crash: { note: 49, base_velocity: 98,  velocity_range: 8,  timing_jitter: 0.010, duration_beats: 0.25 }

humanization:
  timing_jitter: 0.020
  velocity_jitter: 16
  velocity_drift: 0.08

sections:
  intro:
    type: count_in
    hits: 4
    note: 42

  groove:
    bars: 1
    variations:
      - name: rosanna
        weight: 4
        # Jeff Porcaro's Rosanna groove (transcribed):
        # HH: quarter beats (0,4,8,12, X) + swing "trip" at odd steps (3,7,11,15, x)
        #     With swing_hard the "trip" steps are delayed, creating long-short triplet feel
        # Snare: ONLY on beat 3 (pos 8) — this is the half-time backbeat
        # Ghost: pos 3,5 (before beat 2), pos 11,13,15 (around beat 4) — fades in/out
        # Kick: Rosanna hemiola — pos 0, x at 4, X at 6, x at 12, X at 14
        hihat: "X..xX..xX..xX..x"
        snare: "...g.g..X..g.g.g"
        kick:  "X...x.X.....x.X."
      - name: purdie
        weight: 2
        # Bernard Purdie's slightly simpler shuffle — fewer ghost notes
        hihat: "X..xX..xX..xX..x"
        snare: "......g.X....g.g"
        kick:  "X.......X......x"
      - name: open_hat
        weight: 1
        # Open hi-hat on the "trip" of beat 3 for a looser, more open sound
        hihat: "X..xX..xX..xX..x"
        snare: "...g.g..X..g.g.g"
        kick:  "X...x.X.....x.X."

  fill:
    bars: 1
    variations:
      - name: rosanna_outro
        # Rosanna-style fill: snare run with tom interjections
        kick:   "X.......X.....X."
        snare:  "X.xX.xX.xX.xXXXX"
        tom_hi: ".X..X..X..X....."
      - name: triplet_run
        # Simple triplet-feel snare fill leading to crash
        kick:   "X..............."
        snare:  "....x.x.x.x.XXXX"

  crash:
    bars: 1
    variations:
      - name: standard
        crash: "X..............."
        kick:  "X..............."
        hihat: "X..xX..xX..xX..x"

structure:
  fill_every: 16
  break_every: 0
  break_length: 1
  crash_after_fill: true
  dynamic_build: false