[CmdletBinding()]
param(
    [switch]$ValidateOnly
)

$ErrorActionPreference = "Stop"
$ProjectRoot = (Resolve-Path (Join-Path $PSScriptRoot "..")).Path
$FrozenExecutable = Join-Path $ProjectRoot "dist\DoctorWorkstation\DoctorWorkstation.exe"
$ProjectPython = Join-Path $ProjectRoot ".venv\Scripts\python.exe"
$ProjectUvCache = Join-Path $ProjectRoot ".uv-cache"
$SourceRoot = Join-Path $ProjectRoot "src"

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

    if (-not (Test-Path -LiteralPath $Candidate -PathType Leaf)) {
        return $false
    }
    try {
        & $Candidate -c "import sys, httpx, PySide6; raise SystemExit(0 if sys.version_info >= (3, 11) else 1)" 2>$null
        return $LASTEXITCODE -eq 0
    }
    catch {
        return $false
    }
}

function Find-Uv {
    $Command = Get-Command uv -CommandType Application -ErrorAction SilentlyContinue |
        Select-Object -First 1
    if ($Command) { return $Command.Source }
    return $null
}

try {
    if (Test-Path -LiteralPath $FrozenExecutable -PathType Leaf) {
        Write-Host "Using packaged application: $FrozenExecutable"
        if ($ValidateOnly) {
            Write-Host "Windows run entry validation passed."
            exit 0
        }
        & $FrozenExecutable
        $ApplicationExitCode = $LASTEXITCODE
        if ($null -eq $ApplicationExitCode) { $ApplicationExitCode = 0 }
        if ($ApplicationExitCode -ne 0) {
            Write-Host "DoctorWorkstation exited with code $ApplicationExitCode" -ForegroundColor Red
        }
        exit $ApplicationExitCode
    }

    $Python = $null
    if (Test-ProjectPython -Candidate $ProjectPython) {
        $Python = $ProjectPython
        Write-Host "Using existing project environment: $ProjectPython"
    }
    else {
        $Uv = Find-Uv
        if (-not $Uv) {
            throw "No packaged application or usable .venv was found, and uv is not installed."
        }
        if ($ValidateOnly) {
            Write-Host "Source fallback is available through uv: $Uv"
            Write-Host "Windows run entry validation passed."
            exit 0
        }
        Write-Host "Preparing the project environment with uv..."
        $PreviousProjectEnvironment = [Environment]::GetEnvironmentVariable(
            "UV_PROJECT_ENVIRONMENT",
            "Process"
        )
        $PreviousUvCache = [Environment]::GetEnvironmentVariable(
            "UV_CACHE_DIR",
            "Process"
        )
        New-Item -ItemType Directory -Path $ProjectUvCache -Force | Out-Null
        [Environment]::SetEnvironmentVariable(
            "UV_PROJECT_ENVIRONMENT",
            (Join-Path $ProjectRoot ".venv"),
            "Process"
        )
        [Environment]::SetEnvironmentVariable(
            "UV_CACHE_DIR",
            $ProjectUvCache,
            "Process"
        )
        Push-Location $ProjectRoot
        try {
            & $Uv sync --frozen
            if ($LASTEXITCODE -ne 0) {
                throw "uv sync failed with exit code $LASTEXITCODE"
            }
        }
        finally {
            Pop-Location
            [Environment]::SetEnvironmentVariable(
                "UV_PROJECT_ENVIRONMENT",
                $PreviousProjectEnvironment,
                "Process"
            )
            [Environment]::SetEnvironmentVariable(
                "UV_CACHE_DIR",
                $PreviousUvCache,
                "Process"
            )
        }
        if (-not (Test-ProjectPython -Candidate $ProjectPython)) {
            throw "uv completed, but the project Python is still unusable: $ProjectPython"
        }
        $Python = $ProjectPython
    }

    if ($ValidateOnly) {
        Write-Host "Windows run entry validation passed."
        exit 0
    }

    $PreviousPythonPath = [Environment]::GetEnvironmentVariable("PYTHONPATH", "Process")
    $env:PYTHONPATH = if ($PreviousPythonPath) {
        $SourceRoot + [System.IO.Path]::PathSeparator + $PreviousPythonPath
    }
    else {
        $SourceRoot
    }
    Push-Location $ProjectRoot
    try {
        & $Python -m doctor_workstation
        $ApplicationExitCode = $LASTEXITCODE
    }
    finally {
        Pop-Location
        [Environment]::SetEnvironmentVariable("PYTHONPATH", $PreviousPythonPath, "Process")
    }
    if ($null -eq $ApplicationExitCode) { $ApplicationExitCode = 0 }
    if ($ApplicationExitCode -ne 0) {
        Write-Host "DoctorWorkstation exited with code $ApplicationExitCode" -ForegroundColor Red
    }
    exit $ApplicationExitCode
}
catch {
    $FailureExitCode = if ($LASTEXITCODE -is [int] -and $LASTEXITCODE -ne 0) {
        $LASTEXITCODE
    }
    else {
        1
    }
    Write-Host "Unable to start DoctorWorkstation." -ForegroundColor Red
    Write-Host $_.Exception.Message -ForegroundColor Red
    exit $FailureExitCode
}