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

$siteRoot = $PSScriptRoot
$configPath = $null
$localArchive = $null
$remoteArchive = $null
$remoteArchiveMayExist = $false
$deploymentSucceeded = $false
$failureMessage = $null
$locationPushed = $false
$nativeCommands = @{}
$sshOptions = @("-o", "BatchMode=yes", "-o", "ConnectTimeout=10")

function Get-NativeCommandPath {
    param(
        [Parameter(Mandatory)]
        [string]$Name
    )

    $command = Get-Command -Name $Name -CommandType Application -ErrorAction Stop
    return $command.Source
}

function Invoke-CheckedNativeCommand {
    param(
        [Parameter(Mandatory)]
        [string]$Command,

        [Parameter()]
        [string[]]$Arguments = @(),

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

    & $Command @Arguments
    $exitCode = $LASTEXITCODE
    if ($exitCode -ne 0) {
        throw "$Operation failed with exit code $exitCode."
    }
}

function Invoke-CheckedSshScript {
    param(
        [Parameter(Mandatory)]
        [string]$Command,

        [Parameter(Mandatory)]
        [string[]]$Options,

        [Parameter(Mandatory)]
        [string]$Target,

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

    $Script | & $Command @Options $Target "sh -s"
    $exitCode = $LASTEXITCODE
    if ($exitCode -ne 0) {
        throw "Remote release activation failed with exit code $exitCode."
    }
}

try {
    if ($args.Count -gt 0) {
        throw "deploy.ps1 does not accept arguments. Edit deploy.config.psd1 instead."
    }

    if ([string]::IsNullOrWhiteSpace($siteRoot)) {
        throw "Unable to determine the site root. Run deploy.ps1 from a saved file."
    }

    $siteRoot = (Resolve-Path -LiteralPath $siteRoot).Path
    if (-not (Test-Path -LiteralPath (Join-Path $siteRoot "zola.toml") -PathType Leaf)) {
        throw "zola.toml was not found next to deploy.ps1."
    }

    $configPath = Join-Path $siteRoot "deploy.config.psd1"
    if (-not (Test-Path -LiteralPath $configPath -PathType Leaf)) {
        throw (
            "deploy.config.psd1 was not found. " +
            "Copy deploy.config.example.psd1 and enter the local deployment settings."
        )
    }

    $deployConfig = Import-PowerShellDataFile -LiteralPath $configPath
    if ($deployConfig -isnot [System.Collections.IDictionary]) {
        throw "deploy.config.psd1 must contain a PowerShell data hashtable."
    }

    $requiredConfigKeys = @(
        "DeployHost",
        "DeployUser",
        "RemoteBase",
        "IdentityFile",
        "SiteUrl"
    )
    foreach ($key in $requiredConfigKeys) {
        if (-not $deployConfig.Contains($key)) {
            throw "deploy.config.psd1 is missing the required key: $key"
        }
    }

    $DeployHost = ([string]$deployConfig["DeployHost"]).Trim()
    $DeployUser = ([string]$deployConfig["DeployUser"]).Trim()
    $RemoteBase = ([string]$deployConfig["RemoteBase"]).Trim()
    $IdentityFile = ([string]$deployConfig["IdentityFile"]).Trim()
    $siteUrl = ([string]$deployConfig["SiteUrl"]).Trim()

    if ($DeployHost -notmatch '^[A-Za-z0-9._-]+$') {
        throw "DeployHost contains unsupported characters."
    }
    if ($DeployUser -notmatch '^[A-Za-z_][A-Za-z0-9_-]*$') {
        throw "DeployUser contains unsupported characters."
    }

    $RemoteBase = $RemoteBase.TrimEnd('/')
    if (
        $RemoteBase.Length -le 1 -or
        $RemoteBase -notmatch '^/[A-Za-z0-9._/-]+$' -or
        $RemoteBase -match '(^|/)\.\.?(/|$)' -or
        $RemoteBase.Contains('//')
    ) {
        throw "RemoteBase must be a normalized absolute Unix path other than '/'."
    }
    if (-not $RemoteBase.StartsWith('/srv/www/', [System.StringComparison]::Ordinal)) {
        throw "RemoteBase must be located below /srv/www/."
    }

    $parsedSiteUrl = $null
    if (
        -not [System.Uri]::TryCreate(
            $siteUrl,
            [System.UriKind]::Absolute,
            [ref]$parsedSiteUrl
        ) -or
        $parsedSiteUrl.Scheme -ne "https"
    ) {
        throw "SiteUrl must be an absolute HTTPS URL."
    }

    if (-not [string]::IsNullOrWhiteSpace($IdentityFile)) {
        $identityCandidate = $IdentityFile
        if (-not [System.IO.Path]::IsPathRooted($identityCandidate)) {
            $identityCandidate = Join-Path $siteRoot $identityCandidate
        }
        $identityPath = (Resolve-Path -LiteralPath $identityCandidate -ErrorAction Stop).Path
        if (-not (Test-Path -LiteralPath $identityPath -PathType Leaf)) {
            throw "IdentityFile must point to a file."
        }
        $sshOptions += @("-i", $identityPath)
    }

    foreach ($name in @("zola", "tar", "ssh", "scp")) {
        $nativeCommands[$name] = Get-NativeCommandPath -Name $name
    }

    Push-Location -LiteralPath $siteRoot
    $locationPushed = $true

    Write-Host "[1/6] Checking site..."
    Invoke-CheckedNativeCommand `
        -Command $nativeCommands["zola"] `
        -Arguments @("check") `
        -Operation "zola check"

    Write-Host "[2/6] Building site..."
    Invoke-CheckedNativeCommand `
        -Command $nativeCommands["zola"] `
        -Arguments @("build") `
        -Operation "zola build"

    $publicDir = Join-Path $siteRoot "public"
    $publicIndex = Join-Path $publicDir "index.html"
    if (-not (Test-Path -LiteralPath $publicIndex -PathType Leaf)) {
        throw "Build validation failed: public/index.html was not generated."
    }

    $resolvedPublicDir = (Resolve-Path -LiteralPath $publicDir).Path
    $siteRootPrefix = $siteRoot.TrimEnd(
        [System.IO.Path]::DirectorySeparatorChar,
        [System.IO.Path]::AltDirectorySeparatorChar
    ) + [System.IO.Path]::DirectorySeparatorChar
    if (-not $resolvedPublicDir.StartsWith(
        $siteRootPrefix,
        [System.StringComparison]::OrdinalIgnoreCase
    )) {
        throw "Resolved public directory is outside the site root."
    }

    $releaseId = Get-Date -Format "yyyyMMdd-HHmmss"
    $archiveNonce = [System.Guid]::NewGuid().ToString("N")
    $archiveName = "takashi-2521-$releaseId-$archiveNonce.tar.gz"
    $localArchive = Join-Path ([System.IO.Path]::GetTempPath()) $archiveName
    $remoteArchive = "/tmp/$archiveName"
    $remoteTarget = "$DeployUser@$DeployHost"

    Write-Host "[3/6] Creating archive..."
    Invoke-CheckedNativeCommand `
        -Command $nativeCommands["tar"] `
        -Arguments @("-czf", $localArchive, "-C", $resolvedPublicDir, ".") `
        -Operation "tar archive creation"

    if (
        -not (Test-Path -LiteralPath $localArchive -PathType Leaf) -or
        (Get-Item -LiteralPath $localArchive).Length -le 0
    ) {
        throw "Archive validation failed: the local archive is missing or empty."
    }

    Write-Host "[4/6] Uploading release..."
    $scpArguments = @($sshOptions) + @(
        $localArchive,
        "${remoteTarget}:$remoteArchive"
    )
    $remoteArchiveMayExist = $true
    Invoke-CheckedNativeCommand `
        -Command $nativeCommands["scp"] `
        -Arguments $scpArguments `
        -Operation "SCP upload"

    $remoteScript = @'
set -eu
umask 022

base='__REMOTE_BASE__'
release_id='__RELEASE_ID__'
archive='__REMOTE_ARCHIVE__'
release="$base/releases/$release_id"
new_link="$base/current.new"
release_created=0

cleanup() {
    status=$?
    trap - 0
    rm -f -- "$archive" || true
    rm -f -- "$new_link" || true
    if [ "$status" -ne 0 ] && [ "$release_created" -eq 1 ]; then
        rm -rf -- "$release" || true
    fi
    exit "$status"
}
trap cleanup 0

test -d "$base/releases"
test -L "$base/current"
test -f "$base/current/index.html"
test -f "$archive"

if [ -e "$release" ] || [ -L "$release" ]; then
    echo "Release already exists: $release_id" >&2
    exit 1
fi

if [ -e "$new_link" ] || [ -L "$new_link" ]; then
    rm -f -- "$new_link"
fi

mkdir -- "$release"
release_created=1
tar -xzf "$archive" -C "$release"
test -f "$release/index.html"

ln -s "releases/$release_id" "$new_link"
mv -Tf "$new_link" "$base/current"
release_created=0
'@
    $remoteScript = $remoteScript.Replace("__REMOTE_BASE__", $RemoteBase)
    $remoteScript = $remoteScript.Replace("__RELEASE_ID__", $releaseId)
    $remoteScript = $remoteScript.Replace("__REMOTE_ARCHIVE__", $remoteArchive)

    Write-Host "[5/6] Switching release..."
    Invoke-CheckedSshScript `
        -Command $nativeCommands["ssh"] `
        -Options $sshOptions `
        -Target $remoteTarget `
        -Script $remoteScript

    $deploymentSucceeded = $true
}
catch {
    $failureMessage = $_.Exception.Message
}
finally {
    if ($locationPushed) {
        Pop-Location
    }

    if ($null -ne $localArchive -and (Test-Path -LiteralPath $localArchive)) {
        Remove-Item -LiteralPath $localArchive -Force -ErrorAction SilentlyContinue
    }

    if (
        $remoteArchiveMayExist -and
        -not $deploymentSucceeded -and
        $null -ne $remoteArchive
    ) {
        $cleanupCommand = "rm -f -- '$remoteArchive'"
        & $nativeCommands["ssh"] @sshOptions $remoteTarget $cleanupCommand 2>$null | Out-Null
    }
}

if (-not $deploymentSucceeded) {
    [System.Console]::Error.WriteLine("Deployment failed: $failureMessage")
    exit 1
}

Write-Host "[6/6] Done."
Write-Host ""
Write-Host "Release: $releaseId"
Write-Host "URL: $siteUrl"
exit 0