<#
.SYNOPSIS
    Links the extension sources into VS Code's extensions folder for development.

.DESCRIPTION
    Packaging is the wrong loop while you are actually changing code. VS Code loads any
    folder under %USERPROFILE%\.vscode\extensions that has a package.json, so linking the
    source there reduces the edit cycle to "npm run compile" plus a window reload.

    The link is a directory junction rather than a symlink because junctions need no
    elevation and no Developer Mode on Windows, and VS Code cannot tell the difference.

    Run -Unlink before install.ps1: a linked source and an installed .vsix are two copies
    of the same extension id, and VS Code will load one of them arbitrarily.

.PARAMETER Only
    Restrict to these extension ids.

.PARAMETER Unlink
    Remove the links.

.PARAMETER Compile
    Run npm run compile in each extension first.

.EXAMPLE
    .\scripts\dev-link.ps1 -Compile
    .\scripts\dev-link.ps1 -Unlink
#>
[CmdletBinding()]
param(
    [string[]] $Only,
    [switch] $Unlink,
    [switch] $Compile
)

Set-StrictMode -Version Latest
$ErrorActionPreference = 'Stop'
. (Join-Path $PSScriptRoot 'common.ps1')

$config = Get-SetupConfig
$extensionsDir = Join-Path (Get-HomeDir) '.vscode/extensions'
if (-not (Test-Path $extensionsDir)) {
    New-Item -ItemType Directory -Path $extensionsDir -Force | Out-Null
}

$extensions = $config.extensions
if ($Only) {
    $extensions = $extensions | Where-Object { $Only -contains $_.id }
    $missing = $Only | Where-Object { $config.extensions.id -notcontains $_ }
    if ($missing) { throw "not in config.json: $($missing -join ', ')" }
}

foreach ($extension in $extensions) {
    $source = Get-ExtensionPath $extension
    $manifestPath = Join-Path $source 'package.json'
    if (-not (Test-Path $manifestPath)) {
        Write-Warning "no package.json in $source, skipping $($extension.id)"
        continue
    }
    $manifest = Get-Content $manifestPath -Raw | ConvertFrom-Json
    $linkName = "$($manifest.publisher).$($manifest.name)-$($manifest.version)"
    $link = Join-Path $extensionsDir $linkName

    if ($Unlink) {
        if (Test-Path $link) {
            # Remove-Item on a junction deletes the link, not the target -- but only
            # without -Recurse, which would walk into the source and delete the files.
            [System.IO.Directory]::Delete($link)
            Write-Host "unlinked $linkName" -ForegroundColor Green
        } else {
            Write-Host "$linkName was not linked" -ForegroundColor DarkGray
        }
        continue
    }

    if ($Compile) {
        Push-Location $source
        try {
            Write-Host "compiling $($extension.id)..." -ForegroundColor DarkGray
            if (-not (Test-Path (Join-Path $source 'node_modules'))) {
                & npm install --silent --no-audit --no-fund
                if ($LASTEXITCODE -ne 0) { throw "npm install failed for $($extension.id)" }
            }
            & npm run compile --silent
            if ($LASTEXITCODE -ne 0) { throw "compile failed for $($extension.id)" }
        } finally { Pop-Location }
    }

    $main = $manifest.main -replace '^\./', ''
    if (-not (Test-Path (Join-Path $source $main))) {
        Write-Warning ("$($extension.id) has no built output at $main -- it will fail to " +
                       "activate. Pass -Compile.")
    }

    if (Test-Path $link) {
        $item = Get-Item $link -Force
        $target = $item.Target
        if ($target -and @($target)[0] -eq $source) {
            Write-Host "$linkName already linked" -ForegroundColor DarkGray
            continue
        }
        throw ("$link already exists and does not point at $source. Remove it by hand " +
               "(it may be a real installed copy).")
    }

    # A junction needs no privilege on Windows; elsewhere a plain symlink does the same job.
    $linkType = if (Test-IsWindows) { 'Junction' } else { 'SymbolicLink' }
    New-Item -ItemType $linkType -Path $link -Target $source | Out-Null
    Write-Host "linked $linkName -> $source" -ForegroundColor Green
}

Write-Host ''
Write-Host 'Reload the window (Developer: Reload Window) to pick this up.' -ForegroundColor Cyan