# Install Codex skills from this Playbook snapshot into CODEX_HOME.
# - Source: <snapshot>\codex\skills\<skill-name>\
# - Dest:   $env:CODEX_HOME\skills\<skill-name>\  (default CODEX_HOME=$HOME\.codex)
#
# Usage:
#   powershell -File scripts/install_codex_skills.ps1
#   powershell -File scripts/install_codex_skills.ps1 style-cleanup commit-message
#   powershell -File scripts/install_codex_skills.ps1 -Local
#
# Notes:
# - Codex loads skills at startup; restart `codex` after installation.
# - Existing destination skill dirs are backed up with a timestamp suffix.

[CmdletBinding()]
param(
  [Alias('h', '?')]
  [switch]$Help,

  [switch]$Local,
  [switch]$All,
  [Parameter(Mandatory = $false)]
  [string[]]$Skills
)

$ErrorActionPreference = "Stop"

if ($Help) {
  Write-Host "Usage:"
  Write-Host "  powershell -File scripts/install_codex_skills.ps1 -All"
  Write-Host "  powershell -File scripts/install_codex_skills.ps1 -Skills style-cleanup,commit-message"
  Write-Host ""
  Write-Host "Options:"
  Write-Host "  -Local          Install to ./.codex (or CODEX_HOME if set)."
  Write-Host "  -Skills         Comma/space-separated skill names."
  Write-Host "  -All            Install all skills."
  Write-Host "  -Help           Show this help."
  Write-Host ""
  Write-Host "Env:"
  Write-Host "  CODEX_HOME      Target Codex home (default: ~/.codex)."
  exit 0
}

if ($All -and $Skills -and $Skills.Count -gt 0) {
  throw "Use either -All or -Skills, not both."
}
if (-not $All -and (-not $Skills -or $Skills.Count -eq 0)) {
  throw "Missing -All or -Skills. Use -Help for usage."
}
$ScriptDir = Split-Path -Parent $MyInvocation.MyCommand.Path
$Src = (Resolve-Path (Join-Path $ScriptDir "..")).Path
$SkillsSrcRoot = Join-Path $Src "codex/skills"

if (-not (Test-Path $SkillsSrcRoot)) {
  throw "Skills source dir not found: $SkillsSrcRoot"
}

$CodexHome = $env:CODEX_HOME
if ($Local) {
  $localHome = Join-Path (Get-Location) ".codex"
  if (-not $CodexHome) { $CodexHome = $localHome }
}
if (-not $CodexHome) {
  $homeDir = $HOME
  if (-not $homeDir) { $homeDir = $env:USERPROFILE }
  $CodexHome = (Join-Path $homeDir ".codex")
}
$SkillsDstRoot = Join-Path $CodexHome "skills"
New-Item -ItemType Directory -Path $SkillsDstRoot -Force | Out-Null

$timestamp = Get-Date -Format "yyyyMMddHHmmss"

function Install-One([string]$Name) {
  $srcDir = Join-Path $SkillsSrcRoot $Name
  $dstDir = Join-Path $SkillsDstRoot $Name

  if (-not (Test-Path $srcDir)) {
    throw "Skill not found: $Name ($srcDir)"
  }

  if (Test-Path $dstDir) {
    $bak = Join-Path $SkillsDstRoot "$Name.bak.$timestamp"
    Move-Item $dstDir $bak
    Write-Host "Backed up existing skill: $Name -> $(Split-Path -Leaf $bak)"
  }

  Copy-Item $srcDir $dstDir -Recurse -Force
  Write-Host "Installed: $Name"
}

if ($All) {
  foreach ($dir in (Get-ChildItem -Path $SkillsSrcRoot -Directory)) {
    if ($dir.Name.StartsWith(".")) { continue }
    Install-One $dir.Name
  }
} else {
  foreach ($item in $Skills) {
    if (-not $item) { continue }
    foreach ($part in $item.Split(@(',', ' '), [System.StringSplitOptions]::RemoveEmptyEntries)) {
      if (-not $part) { continue }
      Install-One $part
    }
  }
}

Write-Host "Done. Skills installed to: $SkillsDstRoot"