#!/usr/bin/env pwsh
<#
.SYNOPSIS
    Windows equivalent of ./link-dotfiles (the GNU stow script).

.DESCRIPTION
    stow can't run natively on Windows, so this mirrors what it does:
      home_root/*    ->  ~\<name>           (e.g. ~\.zshrc)
      home_config/*  ->  ~\.config\<name>   (e.g. ~\.config\nvim)

    Directories are linked with junctions and files with symlinks/hardlinks,
    none of which need administrator rights (junctions and hardlinks never do;
    symlinks are attempted first in case Developer Mode is on, then we fall
    back). Re-running is safe: correct links are skipped, and any real file or
    directory that would be clobbered is moved aside to <name>.bak first.

.EXAMPLE
    pwsh -File .\link-dotfiles.ps1
#>
[CmdletBinding()]
param(
    # Print what would happen without changing anything.
    [switch]$DryRun
)

$ErrorActionPreference = 'Stop'
$repo = $PSScriptRoot
$home_ = $HOME

# stow metadata files we must never link into the home tree.
$skip = @('.stow-local-ignore', '.stow-global-ignore')

function Get-LinkTarget {
    param([string]$Path)
    $item = Get-Item -LiteralPath $Path -Force -ErrorAction SilentlyContinue
    if ($item -and $item.LinkType) { return $item.Target }
    return $null
}

function Link-Item {
    param(
        [string]$Source,   # absolute path inside the repo
        [string]$Dest      # absolute path under the home tree
    )

    $isDir = (Get-Item -LiteralPath $Source -Force).PSIsContainer

    # Already linked to the right place? Nothing to do.
    $existingTarget = Get-LinkTarget $Dest
    if ($existingTarget -and ($existingTarget -ieq $Source)) {
        Write-Host "  ok    $Dest" -ForegroundColor DarkGray
        return
    }

    if (Test-Path -LiteralPath $Dest) {
        if ($existingTarget) {
            # A link, but pointing elsewhere -> replace it.
            if ($DryRun) { Write-Host "  relink $Dest (was -> $existingTarget)" -ForegroundColor Yellow; return }
            Remove-Item -LiteralPath $Dest -Force -Recurse
        } else {
            # A real file/dir -> back it up rather than destroy it.
            $bak = "$Dest.bak"
            Write-Host "  backup $Dest -> $bak" -ForegroundColor Yellow
            if (-not $DryRun) { Move-Item -LiteralPath $Dest -Destination $bak -Force }
        }
    }

    if ($DryRun) { Write-Host "  link  $Dest -> $Source" -ForegroundColor Cyan; return }

    $parent = Split-Path $Dest -Parent
    if (-not (Test-Path $parent)) { New-Item -ItemType Directory -Path $parent -Force | Out-Null }

    if ($isDir) {
        New-Item -ItemType Junction -Path $Dest -Target $Source | Out-Null
        Write-Host "  junc  $Dest -> $Source" -ForegroundColor Green
    } else {
        # Prefer a real symlink (needs admin or Developer Mode); fall back to a
        # hardlink (same volume, no admin); finally just copy.
        try {
            New-Item -ItemType SymbolicLink -Path $Dest -Target $Source -ErrorAction Stop | Out-Null
            Write-Host "  link  $Dest -> $Source" -ForegroundColor Green
        } catch {
            try {
                New-Item -ItemType HardLink -Path $Dest -Target $Source -ErrorAction Stop | Out-Null
                Write-Host "  hard  $Dest -> $Source" -ForegroundColor Green
            } catch {
                Copy-Item -LiteralPath $Source -Destination $Dest -Force
                Write-Host "  copy  $Dest (could not link; copied)" -ForegroundColor Magenta
            }
        }
    }
}

Write-Host "home_root -> $home_"
Get-ChildItem -LiteralPath (Join-Path $repo 'home_root') -Force |
    Where-Object { $skip -notcontains $_.Name } |
    ForEach-Object { Link-Item $_.FullName (Join-Path $home_ $_.Name) }

$configDir = Join-Path $home_ '.config'
Write-Host "home_config -> $configDir"
Get-ChildItem -LiteralPath (Join-Path $repo 'home_config') -Force |
    Where-Object { $skip -notcontains $_.Name } |
    ForEach-Object { Link-Item $_.FullName (Join-Path $configDir $_.Name) }

# Windows Terminal lives in a package folder outside the stow tree, so link its
# settings.json explicitly. Skipped silently if Terminal isn't installed.
$wtPkg = Get-ChildItem (Join-Path $env:LOCALAPPDATA 'Packages') -Filter 'Microsoft.WindowsTerminal_*' -Directory -ErrorAction SilentlyContinue |
    Select-Object -First 1
$wtSrc = Join-Path $repo 'windows\windows-terminal\settings.json'
if ($wtPkg -and (Test-Path $wtSrc)) {
    $wtDest = Join-Path $wtPkg.FullName 'LocalState\settings.json'
    Write-Host "windows-terminal -> $wtDest"
    Link-Item $wtSrc $wtDest
}

Write-Host "Done." -ForegroundColor Green