# ==============================================================================
# AI Skills Bundle Installer for Windows PowerShell
# The Agentic Engineering Spine for AI Agents
# https://dmg-skills.pages.dev
# ==============================================================================

[CmdletBinding()]
param(
    [switch]$Local,
    [string]$TargetDir = "",
    [string]$Version = "latest",
    [switch]$Force,
    [switch]$DryRun,
    [switch]$Uninstall,
    [switch]$Help
)

$ErrorActionPreference = 'Stop'
$InstallerVersion = "1.0.0"
$BaseUrl = "https://dmg-skills.pages.dev"

if ($env:SKILLS_BASE_URL) {
    $BaseUrl = $env:SKILLS_BASE_URL
}

if ($Help) {
    Write-Host @"
AI Skills Bundle Installer for Windows (PowerShell)

Usage:
  irm https://dmg-skills.pages.dev/install.ps1 | iex
  powershell -ExecutionPolicy Bypass -File install.ps1 [OPTIONS]

Parameters:
  -Local               Install into .\.agents\skills in current folder
  -TargetDir <String>  Install into custom target directory
  -Version <String>    Install specific version (Default: latest)
  -Force               Overwrite existing skill files without prompting
  -DryRun              Simulate installation without making changes
  -Uninstall           Remove the installed skills bundle
  -Help                Display this help message

Examples:
  irm https://dmg-skills.pages.dev/install.ps1 | iex
  & { [scriptblock]::Create((irm https://dmg-skills.pages.dev/install.ps1)) } -Local
  & { [scriptblock]::Create((irm https://dmg-skills.pages.dev/install.ps1)) } -DryRun
"@
    exit 0
}

Write-Host " ___    ____     _____ __   _ ____     " -ForegroundColor Cyan
Write-Host " /   |  /  _/    / ___// /__(_) / /____ " -ForegroundColor Cyan
Write-Host "/ /| |  / /      \__ \/ //_/ / / / ___/ " -ForegroundColor Cyan
Write-Host "/ ___ |_/ /      ___/ / ,< / / / (__  )  " -ForegroundColor Cyan
Write-Host "/_/  |_/___/     /____/_/|_/_/_/_/____/   " -ForegroundColor Cyan
Write-Host " The Agentic Engineering Spine for AI Agents (v$InstallerVersion)" -ForegroundColor DarkGray
Write-Host " https://dmg-skills.pages.dev`n" -ForegroundColor DarkGray

function Select-InstallScope {
    param(
        [string]$WorkspacePath
    )

    $options = @(
        @{ Label = "Global  (~/.agents/skills)"; Desc = "Recommended (available across all projects)"; Value = "Global" },
        @{ Label = "Local   (./.agents/skills)"; Desc = "Current workspace only ($WorkspacePath\.agents\skills)"; Value = "Local" }
    )

    $selected = 0

    try {
        if (-not [Environment]::UserInteractive -or [Console]::IsInputRedirected) {
            return "Global"
        }
    } catch {
        return "Global"
    }

    try {
        [Console]::CursorVisible = $false
    } catch {}

    Write-Host "? Select installation target scope (Use [Up/Down] arrows, press [Enter]):" -ForegroundColor Cyan

    $startTop = [Console]::CursorTop
    $done = $false

    while (-not $done) {
        for ($i = 0; $i -lt $options.Count; $i++) {
            $opt = $options[$i]
            if ($i -eq $selected) {
                Write-Host "  > " -ForegroundColor Green -NoNewline
                Write-Host "$($opt.Label)" -ForegroundColor Green -NoNewline
                Write-Host "  - $($opt.Desc)" -ForegroundColor DarkGray
            } else {
                Write-Host "    $($opt.Label)  - $($opt.Desc)" -ForegroundColor Gray
            }
        }

        try {
            $key = [Console]::ReadKey($true)

            if ($key.Key -eq [ConsoleKey]::UpArrow) {
                $selected = ($selected - 1 + $options.Count) % $options.Count
            } elseif ($key.Key -eq [ConsoleKey]::DownArrow) {
                $selected = ($selected + 1) % $options.Count
            } elseif ($key.Key -eq [ConsoleKey]::Enter) {
                $done = $true
            } elseif ($key.KeyChar -eq '1') {
                $selected = 0
                $done = $true
            } elseif ($key.KeyChar -eq '2') {
                $selected = 1
                $done = $true
            }
        } catch {
            $done = $true
        }

        if (-not $done) {
            try {
                [Console]::SetCursorPosition(0, $startTop)
            } catch {
                $done = $true
            }
        }
    }

    try {
        [Console]::CursorVisible = $true
    } catch {}

    Write-Host ""
    return $options[$selected].Value
}

if (-not $Local -and $TargetDir -eq "" -and -not $env:SKILLS_DIR -and -not $Uninstall -and -not $DryRun -and -not $Force) {
    $currentLoc = (Get-Location).Path
    $chosenScope = Select-InstallScope -WorkspacePath $currentLoc
    if ($chosenScope -eq "Local") {
        $Local = $true
    }
}

$ResolvedDir = "$HOME\.agents\skills"
$Mode = "Global"

if ($Local) {
    $ResolvedDir = Join-Path (Get-Location) ".agents\skills"
    $Mode = "Local"
} elseif ($TargetDir -ne "") {
    $ResolvedDir = $TargetDir
    $Mode = "Custom"
} elseif ($env:SKILLS_DIR) {
    $ResolvedDir = $env:SKILLS_DIR
    $Mode = "Custom (env)"
}

if ($Uninstall) {
    Write-Host "==> Uninstall requested for target: $ResolvedDir" -ForegroundColor Cyan
    if (Test-Path $ResolvedDir) {
        if ($DryRun) {
            Write-Host "[DRY-RUN] Would remove folder: $ResolvedDir" -ForegroundColor Yellow
        } else {
            Remove-Item -Path $ResolvedDir -Recurse -Force
            Write-Host "  [OK] Skills bundle removed successfully from $ResolvedDir" -ForegroundColor Green
        }
    } else {
        Write-Host "  [!] Target folder does not exist: $ResolvedDir" -ForegroundColor Yellow
    }
    exit 0
}

Write-Host "==> Target installation directory: $ResolvedDir ($Mode)" -ForegroundColor Cyan
Write-Host "==> Fetching skills release bundle..." -ForegroundColor Cyan

if ($DryRun) {
    Write-Host "[DRY-RUN] Dry run mode enabled. No changes will be written to disk." -ForegroundColor Yellow
}

$TempDir = Join-Path ([System.IO.Path]::GetTempPath()) ("skills-install-" + [System.Guid]::NewGuid().ToString("N"))
New-Item -ItemType Directory -Path $TempDir -Force | Out-Null

try {
    $ZipUrl = "$BaseUrl/skills-bundle.zip"
    $ZipFile = Join-Path $TempDir "skills-bundle.zip"

    Write-Host "==> Downloading $ZipUrl..." -ForegroundColor DarkGray
    Invoke-WebRequest -Uri $ZipUrl -OutFile $ZipFile -UseBasicParsing

    if (-not (Test-Path $ZipFile) -or (Get-Item $ZipFile).Length -eq 0) {
        throw "Downloaded archive is empty or invalid."
    }

    $StageDir = Join-Path $TempDir "staged"
    Expand-Archive -Path $ZipFile -DestinationPath $StageDir -Force

    $SourceDir = Join-Path $StageDir "skills"
    if (-not (Test-Path $SourceDir)) {
        $SourceDir = $StageDir
    }

    $SkillFolders = Get-ChildItem -Path $SourceDir -Directory
    $SkillCount = $SkillFolders.Count

    Write-Host "==> Discovered $SkillCount AI skills in bundle." -ForegroundColor Cyan

    if ($DryRun) {
        Write-Host "`nSkills that would be installed:" -ForegroundColor Cyan
        foreach ($folder in $SkillFolders) {
            Write-Host "  + $($folder.Name) (to $ResolvedDir\$($folder.Name))" -ForegroundColor Green
        }
        Write-Host "`n[OK] [DRY-RUN] Simulation completed successfully." -ForegroundColor Green
        return
    }

    if (-not (Test-Path $ResolvedDir)) {
        New-Item -ItemType Directory -Path $ResolvedDir -Force | Out-Null
    }

    foreach ($item in (Get-ChildItem -Path $SourceDir)) {
        $destPath = Join-Path $ResolvedDir $item.Name
        if ($item.PSIsContainer) {
            if (Test-Path $destPath) {
                Remove-Item -Path $destPath -Recurse -Force
            }
            Copy-Item -Path $item.FullName -Destination $destPath -Recurse -Force
            Write-Host "  [OK] Installed $($item.Name)" -ForegroundColor Green
        } else {
            Copy-Item -Path $item.FullName -Destination $destPath -Force
            Write-Host "  [OK] Installed $($item.Name)" -ForegroundColor DarkGray
        }
    }

    Write-Host "`n* Installation Complete!" -ForegroundColor Green
    Write-Host "Installed $SkillCount skills to $ResolvedDir`n" -ForegroundColor White

    Write-Host "Quick Start Guide:" -ForegroundColor Cyan
    Write-Host "  1. Initialize repository settings:   /init-skills" -ForegroundColor Yellow
    Write-Host "  2. Shape an idea or architecture:   /grill-with-docs" -ForegroundColor Yellow
    Write-Host "  3. Generate formal specification:   /to-spec" -ForegroundColor Yellow
    Write-Host "  4. Break down tracer tickets:       /to-tickets" -ForegroundColor Yellow
    Write-Host "  5. Implement with TDD seams:        /implement" -ForegroundColor Yellow
    Write-Host "  6. Multi-axis code review:          /code-review" -ForegroundColor Yellow
    Write-Host "`nFor documentation and guides, visit: https://dmg-skills.pages.dev" -ForegroundColor DarkGray
}
finally {
    if (Test-Path $TempDir) {
        Remove-Item -Path $TempDir -Recurse -Force -ErrorAction SilentlyContinue
    }
}