#!/usr/bin/env python3
"""
02-90s-dance-track.py - Full 90s dance track style composition
Creates a multi-track 90s dance track with:
- Track 1: Synthesizer arpeggio lead (GM patch 80)
- Track 2: Synth bass (GM patch 37)
- Track 3: Pad/choir (GM patch 88)
- Track 4: Drums on channel 10
- Track 5: Piano melody (GM patch 1)

Uses MIDIUtil with time in beats (quarter notes).
"""
from midiutil import MIDIFile

# ==============================
# Constants / Configuration
# ==============================
BPM = 128
TEMPO_US = int(60000000 / BPM)
PPQ = 960                    # Ticks per quarter note (MIDIUtil default)
CHANNEL_DRUMS = 9            # MIDI channel 10 = channel index 9
VOLUME = 100

# === Chord data: (root, duration_beats, notes) ===
# vi-IV-V-I in A minor: Am | F | G | E
CHORD_PROGRESSION = [
    (57, 4),   # Am: A3, C4, E4 - 4 beats
    (53, 4),   # F:  F3, A3, C4 - 4 beats
    (55, 4),   # G:  G3, B3, D4 - 4 beats
    (52, 4),   # E:  E3, G#3, B3 - 4 beats
]

# Arpeggio patterns: list of note offsets from chord root
ARP_PATTERNS = [
    [0, 3, 7, 12],  # Ascending: root-3rd-5th-octave
    [12, 7, 3, 0],  # Descending: octave-5th-3rd-root
]

# ==============================
# Create MIDI File
# ==============================
# Format 1: 5 user tracks + 1 tempo track = 6 total tracks
midi = MIDIFile(5, file_format=1, ticks_per_quarternote=PPQ)
midi.addTempo(0, 0, BPM)          # Tempo goes to the implicit tempo track
midi.addTrackName(0, 0, "Arpeggio Lead")
midi.addTrackName(1, 0, "Synth Bass")
midi.addTrackName(2, 0, "Warm Pad")
midi.addTrackName(3, 0, "Drums (Ch10)")
midi.addTrackName(4, 0, "Piano Melody")

# ==============================
# Track 0: Arpeggio Lead (GM Patch 80 - Lead 1 Synth)
# ==============================
track_arp = 0
midi.addProgramChange(track_arp, 0, 0, 80)

current_beat = 0
for chord_root, chord_dur in CHORD_PROGRESSION:
    arp_idx = 0
    arp_pattern = ARP_PATTERNS[arp_idx % len(ARP_PATTERNS)]
    arp_idx += 1
    
    # Each chord tone gets a 1/4 note (1 beat / 4 arp notes = 1/4 beat per note)
    beat_duration = chord_dur / len(arp_pattern)  # 1 beat / 4 = 0.25
    for i, (note_offset, next_offset) in enumerate(zip(arp_pattern, arp_pattern[1:] + arp_pattern[:0])):
        note = chord_root + note_offset
        if arp_idx % 2 == 0:  # Descending on even patterns
            note = chord_root + arp_pattern[-1 - i]
        midi.addNote(track_arp, 0, note, current_beat + i * beat_duration, beat_duration, 90)
    current_beat += chord_dur
    arp_idx += 1

# ==============================
# Track 1: Synth Bass (GM Patch 37)
# ==============================
track_bass = 1
midi.addProgramChange(track_bass, 0, 0, 37)

current_beat = 0
for chord_root, chord_dur in CHORD_PROGRESSION:
    # Root notes on beats 1 and 3 (quarter notes)
    midi.addNote(track_bass, 0, chord_root, current_beat, 0.5, 100)
    midi.addNote(track_bass, 0, chord_root + 7, current_beat + 2, 0.5, 95)
    current_beat += chord_dur

# ==============================
# Track 2: Warm Pad (GM Patch 88)
# ==============================
track_pad = 2
midi.addProgramChange(track_pad, 0, 0, 88)

# Add reverb and expression to pad
midi.addControllerEvent(track_pad, 0, 0, 91, 60)   # Reverb CC91 = 60
midi.addControllerEvent(track_pad, 0, 0, 93, 70)   # Chorus CC93 = 70

current_beat = 0
for chord_root, chord_dur in CHORD_PROGRESSION:
    # Pad plays the full chord for 3.5 of 4 beats with fade
    root = chord_root
    third = chord_root + 4
    fifth = chord_root + 7
    # Note On (pad instruments need note_on to sound)
    for pitch in [root, third, fifth]:
        midi.addNote(track_pad, 0, pitch, current_beat, chord_dur - 0.5, 70)
    current_beat += chord_dur

# ==============================
# Track 3: Drums (Channel 10 = MIDI channel 9)
# Standard 90s dance pattern:
#   Kick on 1, 2, 3, 4  (kick = note 36)
#   Snare on 2, 4       (snare = note 38)
#   Closed HH on every eighth (hh closed = note 42)
#   Open HH on off-beats  (hh open = note 46)
# ==============================
track_drums = 3

current_beat = 0
total_bars = len(CHORD_PROGRESSION)  # One bar = 4 chords
for bar in range(total_bars):
    for beat in range(4):
        # Kick on every quarter note
        midi.addNote(track_drums, CHANNEL_DRUMS, 36, current_beat + beat, 0.2, 110)
        # Snare on beats 2 and 4
        if beat in [1, 3]:
            midi.addNote(track_drums, CHANNEL_DRUMS, 38, current_beat + beat, 0.2, 100)
        # Closed hi-hat on every eighth note
        midi.addNote(track_drums, CHANNEL_DRUMS, 42, current_beat + beat + 0.5, 0.15, 80)
        # Open hi-hat on off-beats (between quarters)
        midi.addNote(track_drums, CHANNEL_DRUMS, 46, current_beat + beat + 0.25, 0.1, 70)
        midi.addNote(track_drums, CHANNEL_DRUMS, 46, current_beat + beat + 0.75, 0.1, 70)

    current_beat += 4  # One bar = 4 beats

# ==============================
# Track 4: Piano Melody (GM Patch 1)
# Simple pentatonic melody in A minor
# ==============================
track_piano = 4
midi.addProgramChange(track_piano, 0, 0, 1)

# Melody notes: (beat, pitch, duration, velocity)
melody_notes = [
    # Verse melody - A minor pentatonic
    (0, 69, 0.5, 95),   # E4, half beat
    (0.5, 72, 0.5, 90), # F4
    (1.0, 69, 0.5, 85), # E4
    (1.5, 67, 0.5, 90), # D4
    
    (2.0, 65, 0.5, 95), # C4
    (2.5, 67, 0.5, 90), # D4
    (3.0, 69, 1.0, 85), # E4, whole beat
    
    # Repeat with variation
    (4.0, 69, 0.5, 95), # E4
    (4.5, 72, 0.5, 90), # F4
    (5.0, 74, 0.5, 95), # G4
    (5.5, 72, 0.5, 90), # F4
    
    (6.0, 69, 1.0, 85), # E4
    (7.0, 67, 0.5, 80), # D4
    (7.5, 65, 1.0, 75), # C4, whole beat
]

for beat, pitch, duration, vol in melody_notes:
    midi.addNote(track_piano, 0, pitch, beat, duration, vol)

# ==============================
# Write to Disk
# ==============================
with open("90s-dance-track.mid", "wb") as output_file:
    midi.writeFile(output_file)

print("Written: 90s-dance-track.mid")
print(f"  Tracks: {len(CHORD_PROGRESSION)} chord bars at {BPM} BPM")