<#

.SYNOPSIS
This is a Powershell script to bootstrap a Cake build.

.DESCRIPTION
This Powershell script will download NuGet if missing, restore NuGet tools (including Cake)
and execute your Cake build script with the parameters you provide.

.PARAMETER Script
The build script to execute.
.PARAMETER Target
The build script target to run.
.PARAMETER Verbosity
Specifies the amount of information to be displayed.
.PARAMETER Experimental
Tells Cake to use the latest Roslyn release.
.PARAMETER WhatIf
Performs a dry run of the build script.
No tasks will be executed.
.PARAMETER Mono
Tells Cake to use the Mono scripting engine.
.PARAMETER SkipToolPackageRestore
Skips restoring of packages.
.PARAMETER ScriptArgs
Remaining arguments are added here.

.LINK
http://cakebuild.net

#>

[CmdletBinding()]
Param(
    [string]$Script = "build.cake",
    [string]$Target = "Default",
    [ValidateSet("Quiet", "Minimal", "Normal", "Verbose", "Diagnostic")]
    [string]$Verbosity = "Verbose",
    [switch]$Experimental,
    [Alias("DryRun","Noop")]
    [switch]$WhatIf,
    [switch]$Mono,
    [switch]$SkipToolPackageRestore,
    [Parameter(Position=0,Mandatory=$false,ValueFromRemainingArguments=$true)]
    [string[]]$ScriptArgs
)

[Reflection.Assembly]::LoadWithPartialName("System.Security") | Out-Null
function MD5HashFile([string] $filePath)
{
    if ([string]::IsNullOrEmpty($filePath) -or !(Test-Path $filePath -PathType Leaf))
    {
        return $null
    }

    [System.IO.Stream] $file = $null;
    [System.Security.Cryptography.MD5] $md5 = $null;
    try
    {
        $md5 = [System.Security.Cryptography.MD5]::Create()
        $file = [System.IO.File]::OpenRead($filePath)
        return [System.BitConverter]::ToString($md5.ComputeHash($file))
    }
    finally
    {
        if ($file -ne $null)
        {
            $file.Dispose()
        }
    }
}

Write-Host "Preparing to run build script..."

if(!$PSScriptRoot){
    $PSScriptRoot = Split-Path $MyInvocation.MyCommand.Path -Parent
}

$TOOLS_DIR = Join-Path $PSScriptRoot "tools"
$NUGET_EXE = Join-Path $TOOLS_DIR "nuget.exe"
$CAKE_EXE = Join-Path $TOOLS_DIR "Cake/Cake.exe"
$NUGET_URL = "https://dist.nuget.org/win-x86-commandline/latest/nuget.exe"
$PACKAGES_CONFIG = Join-Path $TOOLS_DIR "packages.config"
$PACKAGES_CONFIG_MD5 = Join-Path $TOOLS_DIR "packages.config.md5sum"

$UseMono = "";
if($Mono.IsPresent) {
    Write-Verbose -Message "Using the Mono based scripting engine."
    $UseMono = "-mono"
}

$UseExperimental = "";
if($Experimental.IsPresent -and !($Mono.IsPresent)) {
    Write-Verbose -Message "Using experimental version of Roslyn."
    $UseExperimental = "-experimental"
}

$UseDryRun = "";
if($WhatIf.IsPresent) {
    $UseDryRun = "-dryrun"
}

if ((Test-Path $PSScriptRoot) -and !(Test-Path $TOOLS_DIR)) {
    Write-Verbose -Message "Creating tools directory..."
    New-Item -Path $TOOLS_DIR -Type directory | out-null
}

if (!(Test-Path $PACKAGES_CONFIG)) {
    Write-Verbose -Message "Downloading packages.config..."
    try { (New-Object System.Net.WebClient).DownloadFile("http://cakebuild.net/download/bootstrapper/packages", $PACKAGES_CONFIG) } catch {
        Throw "Could not download packages.config."
    }
}

if (!(Test-Path $NUGET_EXE)) {
    Write-Verbose -Message "Trying to find nuget.exe in PATH..."
    $existingPaths = $Env:Path -Split ';' | Where-Object { (![string]::IsNullOrEmpty($_)) -and (Test-Path $_) }
    $NUGET_EXE_IN_PATH = Get-ChildItem -Path $existingPaths -Filter "nuget.exe" | Select -First 1
    if ($NUGET_EXE_IN_PATH -ne $null -and (Test-Path $NUGET_EXE_IN_PATH.FullName)) {
        Write-Verbose -Message "Found in PATH at $($NUGET_EXE_IN_PATH.FullName)."
        $NUGET_EXE = $NUGET_EXE_IN_PATH.FullName
    }
}

if (!(Test-Path $NUGET_EXE)) {
    Write-Verbose -Message "Downloading NuGet.exe..."
    try {
        (New-Object System.Net.WebClient).DownloadFile($NUGET_URL, $NUGET_EXE)
    } catch {
        Throw "Could not download NuGet.exe."
    }
}

$ENV:NUGET_EXE = $NUGET_EXE

if(-Not $SkipToolPackageRestore.IsPresent) {
    Push-Location
    Set-Location $TOOLS_DIR

    [string] $md5Hash = MD5HashFile($PACKAGES_CONFIG)
    if((!(Test-Path $PACKAGES_CONFIG_MD5)) -Or
      ($md5Hash -ne (Get-Content $PACKAGES_CONFIG_MD5 ))) {
        Write-Verbose -Message "Missing or changed package.config hash..."
        Remove-Item * -Recurse -Exclude packages.config,nuget.exe
    }

    Write-Verbose -Message "Restoring tools from NuGet..."
    $NuGetOutput = Invoke-Expression "&`"$NUGET_EXE`" install -ExcludeVersion -OutputDirectory `"$TOOLS_DIR`""

    if ($LASTEXITCODE -ne 0) {
        Throw "An error occured while restoring NuGet tools."
    }
    else
    {
        $md5Hash | Out-File $PACKAGES_CONFIG_MD5 -Encoding "ASCII"
    }
    Write-Verbose -Message ($NuGetOutput | out-string)
    Pop-Location
}

if (!(Test-Path $CAKE_EXE)) {
    Throw "Could not find Cake.exe at $CAKE_EXE"
}

Write-Host "Running build script..."
Invoke-Expression "& `"$CAKE_EXE`" `"$Script`" -target=`"$Target`" -verbosity=`"$Verbosity`" $UseMono $UseDryRun $UseExperimental $ScriptArgs"
exit $LASTEXITCODE