[CmdletBinding()]
param()

Set-StrictMode -Version Latest
$ErrorActionPreference = 'Stop'

$root = $PSScriptRoot
$binPath = Join-Path $root 'bin'
$shellScript = Join-Path $root 'shell\MS.Open.ps1'

if (-not (Test-Path -LiteralPath $binPath -PathType Container)) {
    throw "Missing bin directory: $binPath"
}

if (-not (Test-Path -LiteralPath $shellScript -PathType Leaf)) {
    throw "Missing shell integration script: $shellScript"
}

function Normalize-PathEntry {
    param([string]$Value)

    if ([string]::IsNullOrWhiteSpace($Value)) {
        return ''
    }

    return $Value.Trim().TrimEnd('\')
}

function Add-UserPath {
    param([string]$PathToAdd)

    $current = [Environment]::GetEnvironmentVariable('Path', 'User')
    $entries = @(
        $current -split ';' |
        ForEach-Object { Normalize-PathEntry $_ } |
        Where-Object { $_ }
    )

    $normalizedTarget = Normalize-PathEntry $PathToAdd
    $alreadyPresent = $entries | Where-Object {
        $_.Equals($normalizedTarget, [StringComparison]::OrdinalIgnoreCase)
    }

    if (-not $alreadyPresent) {
        $newPath = (@($entries) + $normalizedTarget) -join ';'
        [Environment]::SetEnvironmentVariable('Path', $newPath, 'User')
        Write-Host "Added to user PATH: $PathToAdd"
    }
    else {
        Write-Host "Already in user PATH: $PathToAdd"
    }

    $processEntries = @($env:Path -split ';')
    $inCurrentProcess = $processEntries | Where-Object {
        (Normalize-PathEntry $_).Equals($normalizedTarget, [StringComparison]::OrdinalIgnoreCase)
    }

    if (-not $inCurrentProcess) {
        $env:Path = "$env:Path;$PathToAdd"
    }
}

function Update-PowerShellProfile {
    param(
        [Parameter(Mandatory)]
        [string]$ProfilePath,

        [Parameter(Mandatory)]
        [string]$IntegrationScript
    )

    $directory = Split-Path -Parent $ProfilePath
    New-Item -ItemType Directory -Path $directory -Force | Out-Null

    $beginMarker = '# >>> MS.Open >>>'
    $endMarker = '# <<< MS.Open <<<'
    $escapedScript = $IntegrationScript.Replace("'", "''")

    $block = @"
$beginMarker
`$msOpenShell = '$escapedScript'
if (Test-Path -LiteralPath `$msOpenShell) {
    . `$msOpenShell
}
$endMarker
"@

    $content = ''
    if (Test-Path -LiteralPath $ProfilePath) {
        $content = Get-Content -LiteralPath $ProfilePath -Raw
        $timestamp = Get-Date -Format 'yyyyMMdd-HHmmss'
        Copy-Item -LiteralPath $ProfilePath -Destination "$ProfilePath.msopen-backup-$timestamp"
    }

    $pattern = "(?ms)^$([regex]::Escape($beginMarker)).*?^$([regex]::Escape($endMarker))\s*"
    $cleaned = [regex]::Replace($content, $pattern, '').TrimEnd()

    if ($cleaned) {
        $newContent = "$cleaned`r`n`r`n$block`r`n"
    }
    else {
        $newContent = "$block`r`n"
    }

    Set-Content -LiteralPath $ProfilePath -Value $newContent -Encoding UTF8
    Write-Host "Configured PowerShell profile: $ProfilePath"
}

Add-UserPath -PathToAdd $binPath

$documents = [Environment]::GetFolderPath('MyDocuments')
$profiles = @(
    (Join-Path $documents 'WindowsPowerShell\Microsoft.PowerShell_profile.ps1'),
    (Join-Path $documents 'PowerShell\Microsoft.PowerShell_profile.ps1')
) | Select-Object -Unique

foreach ($profilePath in $profiles) {
    Update-PowerShellProfile -ProfilePath $profilePath -IntegrationScript $shellScript
}

Write-Host ''
Write-Host 'MS.Open is installed.'
Write-Host 'Restart your terminal, then try:'
Write-Host '  open .'
Write-Host '  mkcd test-folder'
Write-Host '  paths'