# Ensure web frontend: npm install + optional dist build for Docker nginx.
# Called automatically by start.ps1 / start-host.ps1 (no manual npm).
param(
    [switch]$BuildDist
)

$ErrorActionPreference = "Stop"
$Root = Split-Path -Parent $PSScriptRoot
if (-not (Test-Path (Join-Path $Root "web\package.json"))) {
    throw "web/package.json not found under repo root"
}
$WebDir = Join-Path $Root "web"

$npmCmd = Get-Command npm.cmd -ErrorAction SilentlyContinue
if (-not $npmCmd) { $npmCmd = Get-Command npm -ErrorAction SilentlyContinue }
if (-not $npmCmd) { throw "npm not found" }

Push-Location $WebDir
try {
    if (-not (Test-Path "node_modules")) {
        Write-Host "  npm install (web) ..." -ForegroundColor DarkGray
        & $npmCmd.Source install
        if ($LASTEXITCODE -ne 0) { throw "npm install failed" }
    }

    if (-not $BuildDist) {
        # Clear stale native exit code left by caller (e.g. docker compose failure)
        $global:LASTEXITCODE = 0
        return
    }

    $distIndex = Join-Path $WebDir "dist\index.html"
    $needBuild = -not (Test-Path $distIndex)
    if (-not $needBuild) {
        $distTime = (Get-Item $distIndex).LastWriteTime
        $newer = Get-ChildItem -Path (Join-Path $WebDir "src") -Recurse -File -ErrorAction SilentlyContinue |
            Where-Object { $_.LastWriteTime -gt $distTime } |
            Select-Object -First 1
        if ($newer) { $needBuild = $true }
        $cfgNewer = Get-ChildItem -Path $WebDir -File -ErrorAction SilentlyContinue |
            Where-Object { $_.Name -match '^(vite\.config|index\.html|package\.json)' -and $_.LastWriteTime -gt $distTime } |
            Select-Object -First 1
        if ($cfgNewer) { $needBuild = $true }
    }
    if ($needBuild) {
        Write-Host "  npm run build (web dist, includes /#/preview) ..." -ForegroundColor DarkGray
        & $npmCmd.Source run build
        if ($LASTEXITCODE -ne 0) { throw "npm run build failed" }
        if (-not (Test-Path $distIndex)) { throw "web/dist/index.html missing after build" }
        Write-Host "  OK  web/dist ready" -ForegroundColor DarkGray
    } else {
        Write-Host "  OK  web/dist up to date" -ForegroundColor DarkGray
    }
    $global:LASTEXITCODE = 0
} finally {
    Pop-Location
}