[CmdletBinding()]
param()

$ErrorActionPreference = "Stop"
$ProjectRoot = (Resolve-Path (Join-Path $PSScriptRoot "..")).Path
$ToolVersion = "6.7.3"
$ToolRoot = Join-Path $ProjectRoot ".build-tools\inno-setup-$ToolVersion"
$Compiler = Join-Path $ToolRoot "ISCC.exe"
$DownloadRoot = Join-Path $ProjectRoot ".build-tools\downloads"
$Installer = Join-Path $DownloadRoot "innosetup-$ToolVersion.exe"
$InstallerUrl = (
    "https://github.com/jrsoftware/issrc/releases/download/" +
    "is-6_7_3/innosetup-$ToolVersion.exe"
)
$InstallerSha256 = "9C73C3BAE7ED48D44112A0F48E66742C00090BDB5BEF71D9D3C056C66E97B732"
$LanguageRoot = Join-Path $ProjectRoot ".build-tools\inno-languages"
$ChineseMessages = Join-Path $LanguageRoot "ChineseSimplified.isl"
$ChineseMessagesUrl = (
    "https://raw.githubusercontent.com/jrsoftware/issrc/" +
    "6ef32198ef1f7b7b375cd4b6b90896c2a58eb4c2/Files/Languages/ChineseSimplified.isl"
)
$ChineseMessagesSha256 = "E0B0B350E2245F3C5E65586DFE43D574F6E7F06F2261149ABA284954B3FC9A8D"

function Test-Compiler {
    param([Parameter(Mandatory = $true)][string]$Candidate)

    if (-not (Test-Path -LiteralPath $Candidate -PathType Leaf)) {
        return $false
    }
    $ReleaseNotes = Join-Path (Split-Path -Parent $Candidate) "whatsnew.htm"
    if (-not (Test-Path -LiteralPath $ReleaseNotes -PathType Leaf)) {
        return $false
    }
    $ReleaseText = [System.IO.File]::ReadAllText($ReleaseNotes)
    $VersionMatch = [regex]::Match($ReleaseText, '<span class="ver">([0-9.]+)')
    return $VersionMatch.Success -and $VersionMatch.Groups[1].Value -eq $ToolVersion
}

New-Item -ItemType Directory -Path $LanguageRoot -Force | Out-Null
if (Test-Path -LiteralPath $ChineseMessages -PathType Leaf) {
    $ExistingLanguageHash = (Get-FileHash -LiteralPath $ChineseMessages -Algorithm SHA256).Hash
    if ($ExistingLanguageHash -ne $ChineseMessagesSha256) {
        Remove-Item -LiteralPath $ChineseMessages -Force
    }
}
if (-not (Test-Path -LiteralPath $ChineseMessages -PathType Leaf)) {
    Write-Host "Downloading the pinned Simplified Chinese installer messages..."
    Invoke-WebRequest -Uri $ChineseMessagesUrl -OutFile $ChineseMessages -UseBasicParsing
}
$ActualLanguageHash = (Get-FileHash -LiteralPath $ChineseMessages -Algorithm SHA256).Hash
if ($ActualLanguageHash -ne $ChineseMessagesSha256) {
    throw "Inno Setup language checksum mismatch. Expected $ChineseMessagesSha256; found $ActualLanguageHash"
}

foreach ($Candidate in @(
    $Compiler,
    (Join-Path ${env:ProgramFiles(x86)} "Inno Setup 6\ISCC.exe"),
    (Join-Path $env:LOCALAPPDATA "Programs\Inno Setup 6\ISCC.exe")
)) {
    if ($Candidate -and (Test-Compiler -Candidate $Candidate)) {
        Write-Output (Resolve-Path -LiteralPath $Candidate).Path
        exit 0
    }
}

New-Item -ItemType Directory -Path $DownloadRoot -Force | Out-Null
if (Test-Path -LiteralPath $Installer -PathType Leaf) {
    $ExistingHash = (Get-FileHash -LiteralPath $Installer -Algorithm SHA256).Hash
    if ($ExistingHash -ne $InstallerSha256) {
        Remove-Item -LiteralPath $Installer -Force
    }
}

if (-not (Test-Path -LiteralPath $Installer -PathType Leaf)) {
    Write-Host "Downloading pinned Inno Setup $ToolVersion compiler..."
    Invoke-WebRequest -Uri $InstallerUrl -OutFile $Installer -UseBasicParsing
}

$ActualHash = (Get-FileHash -LiteralPath $Installer -Algorithm SHA256).Hash
if ($ActualHash -ne $InstallerSha256) {
    throw "Inno Setup download checksum mismatch. Expected $InstallerSha256; found $ActualHash"
}
$Signature = Get-AuthenticodeSignature -LiteralPath $Installer
if ($Signature.Status -ne [System.Management.Automation.SignatureStatus]::Valid) {
    throw "Inno Setup download does not have a valid Authenticode signature: $($Signature.Status)"
}
if (-not $Signature.SignerCertificate -or
    $Signature.SignerCertificate.Subject -notmatch "O=Pyrsys B\.V\.") {
    throw "Inno Setup download has an unexpected signer"
}

New-Item -ItemType Directory -Path $ToolRoot -Force | Out-Null
Write-Host "Installing the pinned Inno Setup compiler into $ToolRoot ..."
& $Installer /VERYSILENT /SUPPRESSMSGBOXES /NORESTART /CURRENTUSER "/DIR=$ToolRoot"
if ($LASTEXITCODE -ne 0) {
    throw "Inno Setup compiler installation failed with exit code $LASTEXITCODE"
}
if (-not (Test-Compiler -Candidate $Compiler)) {
    throw "Inno Setup installation completed without ISCC.exe: $Compiler"
}

Write-Output $Compiler