<#
    MIDI Grid installer.

    Registers the scripts as Reaper actions and binds them, by editing
    reaper-kb.ini directly. This is done rather than via "Import key map"
    because Reaper's importer silently converts unresolved script bindings
    into "No-op (no action)" entries -- see README, Installation notes.

    REAPER MUST BE CLOSED. It rewrites reaper-kb.ini on exit and will
    discard anything written while it is running.

    Usage:   powershell -ExecutionPolicy Bypass -File install.ps1
             powershell -ExecutionPolicy Bypass -File install.ps1 -Uninstall
#>
[CmdletBinding()]
param(
    [string] $ScriptDir = $PSScriptRoot,
    [string] $ResourcePath = "$env:APPDATA\REAPER",
    [switch] $Uninstall
)

$ErrorActionPreference = 'Stop'

$kb = Join-Path $ResourcePath 'reaper-kb.ini'
if (-not (Test-Path $kb)) { throw "reaper-kb.ini not found at $kb" }

if (Get-Process reaper* -ErrorAction SilentlyContinue) {
    throw "REAPER is running. Close it completely and run this again."
}

# id, section, description, script filename
$actions = @(
    @('RSmidigrid_open',   0,     'MIDI Grid: Open selected item in grid mode', 'MidiGrid_OpenInGrid.lua'),
    @('RSmidigrid_daemon', 0,     'MIDI Grid: Preview daemon (auto-started)',   'MidiGrid_Daemon.lua'),
    @('RSmidigrid_mode',   32060, 'MIDI Grid: Toggle grid mode',                'MidiGrid_ToggleMode.lua'),
    @('RSmidigrid_left',   32060, 'MIDI Grid: Cursor left one cell',            'MidiGrid_Left.lua'),
    @('RSmidigrid_right',  32060, 'MIDI Grid: Cursor right one cell',           'MidiGrid_Right.lua'),
    @('RSmidigrid_up',     32060, 'MIDI Grid: Pitch up one scale degree',       'MidiGrid_Up.lua'),
    @('RSmidigrid_down',   32060, 'MIDI Grid: Pitch down one scale degree',     'MidiGrid_Down.lua'),
    @('RSmidigrid_cell',   32060, 'MIDI Grid: Toggle note at cursor cell',      'MidiGrid_ToggleCell.lua'),
    @('RSmidigrid_hold',   32060, 'MIDI Grid: Toggle hold mode',                'MidiGrid_ToggleHold.lua'),
    @('RSmidigrid_audit',  32060, 'MIDI Grid: Repeat current cell',             'MidiGrid_AuditionCell.lua'),
    @('RSmidigrid_scale',  32060, 'MIDI Grid: Set root and scale',              'MidiGrid_SetScale.lua')
)

# flags, keycode, section, id
#   flags: 1 base, +4 Shift, +8 Ctrl, +16 Alt
#   section: 0 = Main, 32060 = MIDI Editor
$keys = @(
    @(21, 71,    0,     'RSmidigrid_open'),
    @(17, 71,    32060, 'RSmidigrid_mode'),
    @(1,  32805, 32060, 'RSmidigrid_left'),
    @(1,  32807, 32060, 'RSmidigrid_right'),
    @(1,  32806, 32060, 'RSmidigrid_up'),
    @(1,  32808, 32060, 'RSmidigrid_down'),
    @(1,  13,    32060, 'RSmidigrid_cell'),
    @(17, 72,    32060, 'RSmidigrid_hold'),
    @(17, 65,    32060, 'RSmidigrid_audit'),
    @(17, 83,    32060, 'RSmidigrid_scale')
)

$backup = "$kb.midigrid-backup"
if (-not (Test-Path $backup)) {
    Copy-Item $kb $backup
    Write-Host "Backed up original to $backup"
}

$lines = [System.Collections.Generic.List[string]]::new()
$lines.AddRange([System.IO.File]::ReadAllLines($kb))

# Drop any previous MIDI Grid lines so re-running is idempotent.
for ($i = $lines.Count - 1; $i -ge 0; $i--) {
    if ($lines[$i] -match '(?i)RSmidigrid') { $lines.RemoveAt($i) }
}

if ($Uninstall) {
    [System.IO.File]::WriteAllLines($kb, $lines, (New-Object System.Text.UTF8Encoding($false)))
    Write-Host "Removed MIDI Grid actions and bindings."
    Write-Host "Note: keys it had taken over (arrows, Enter) are now unbound in the"
    Write-Host "MIDI editor. Rebind them, or restore $backup."
    return
}

foreach ($a in $actions) {
    $path = Join-Path $ScriptDir $a[3]
    if (-not (Test-Path $path)) { throw "Missing script: $path" }
    $lines.Insert(0, ('SCR 4 {0} {1} "{2}" {3}' -f $a[1], $a[0], $a[2], $path))
}

# KEY lines reference the *named command*, which is the SCR id with a
# leading underscore. Without it Reaper cannot resolve the binding and the
# key silently does nothing.
foreach ($k in $keys) {
    $new = 'KEY {0} {1} _{3} {2}' -f $k[0], $k[1], $k[2], $k[3]
    $pat = '^KEY {0} {1} \S+ {2}(\s|$)' -f $k[0], $k[1], $k[2]
    $found = $false
    for ($i = 0; $i -lt $lines.Count; $i++) {
        if ($lines[$i] -match $pat) { $lines[$i] = $new; $found = $true; break }
    }
    if (-not $found) { $lines.Add($new) }
}

[System.IO.File]::WriteAllLines($kb, $lines, (New-Object System.Text.UTF8Encoding($false)))

Write-Host "Installed $($actions.Count) actions and $($keys.Count) key bindings."
Write-Host "Start REAPER, select a MIDI item, and press Alt+Shift+G."