[CmdletBinding()]
param(
    [string]$BackendBindAddress = "0.0.0.0",
    [int]$BackendPort = 8000,
    [string]$FrontendBindAddress = "0.0.0.0",
    [int]$FrontendPort = 5173,
    [string]$ApiBaseUrl = "",
    [switch]$SkipFrontend,
    [switch]$NoBrowser
)

$ErrorActionPreference = "Stop"

$ProjectRoot = Split-Path -Parent $MyInvocation.MyCommand.Path
$RuntimeDir = Join-Path $ProjectRoot ".runtime"
$LogDir = Join-Path $RuntimeDir "logs"
$StatePath = Join-Path $RuntimeDir "processes.json"
$PythonPath = Join-Path $ProjectRoot ".venv\Scripts\python.exe"
$BackendDir = Join-Path $ProjectRoot "backend"
$FrontendDir = Join-Path $ProjectRoot "frontend"
$NodeModulesDir = Join-Path $FrontendDir "node_modules"

function Get-ListeningProcessId {
    param([int]$Port)

    $connection = Get-NetTCPConnection -LocalPort $Port -State Listen -ErrorAction SilentlyContinue |
        Select-Object -First 1
    if ($null -eq $connection) {
        return $null
    }
    return [int]$connection.OwningProcess
}

function Wait-ForPort {
    param(
        [int]$Port,
        [System.Diagnostics.Process]$Launcher,
        [int]$TimeoutSeconds = 30
    )

    $deadline = (Get-Date).AddSeconds($TimeoutSeconds)
    while ((Get-Date) -lt $deadline) {
        $listenerPid = Get-ListeningProcessId -Port $Port
        if ($null -ne $listenerPid) {
            return $listenerPid
        }
        if ($Launcher.HasExited) {
            throw "启动进程已退出，退出码：$($Launcher.ExitCode)"
        }
        Start-Sleep -Milliseconds 300
        $Launcher.Refresh()
    }
    throw "等待端口 $Port 监听超时（${TimeoutSeconds} 秒）"
}

function Stop-ProcessTree {
    param([int]$RootProcessId)

    if ($RootProcessId -le 0) {
        return
    }

    # 先结束子进程，避免 npm/cmd 退出后留下独立的 Vite 进程。
    $pending = [System.Collections.Generic.List[int]]::new()
    $pending.Add($RootProcessId)
    $allProcessIds = [System.Collections.Generic.List[int]]::new()
    while ($pending.Count -gt 0) {
        $currentProcessId = $pending[0]
        $pending.RemoveAt(0)
        $allProcessIds.Add($currentProcessId)
        Get-CimInstance Win32_Process -Filter "ParentProcessId = $currentProcessId" -ErrorAction SilentlyContinue |
            ForEach-Object { $pending.Add([int]$_.ProcessId) }
    }

    $orderedProcessIds = @($allProcessIds)
    [array]::Reverse($orderedProcessIds)
    foreach ($processId in $orderedProcessIds) {
        Stop-Process -Id $processId -Force -ErrorAction SilentlyContinue
    }
}

if (-not (Test-Path -LiteralPath $PythonPath -PathType Leaf)) {
    throw "未找到 Python 虚拟环境：$PythonPath。请先执行 python -m venv .venv 并安装后端依赖。"
}
if (-not (Test-Path -LiteralPath $BackendDir -PathType Container)) {
    throw "未找到后端目录：$BackendDir"
}
if (-not $SkipFrontend) {
    if (-not (Get-Command npm.cmd -ErrorAction SilentlyContinue)) {
        throw "未找到 npm.cmd，请先安装 Node.js 并确认 npm 已加入 PATH。"
    }
    if (-not (Test-Path -LiteralPath $NodeModulesDir -PathType Container)) {
        throw "未找到前端依赖目录：$NodeModulesDir。请先在 frontend 目录执行 npm install。"
    }
}

$portsToCheck = @($BackendPort)
if (-not $SkipFrontend) {
    $portsToCheck += $FrontendPort
}
foreach ($port in $portsToCheck) {
    if ($null -ne (Get-ListeningProcessId -Port $port)) {
        throw "端口 $port 已被占用。请先关闭占用进程，或通过参数指定其他端口。"
    }
}

New-Item -ItemType Directory -Path $LogDir -Force | Out-Null
if (Test-Path -LiteralPath $StatePath) {
    Remove-Item -LiteralPath $StatePath -Force
}

$backendProcess = $null
$frontendProcess = $null
try {
    Write-Host "正在启动后端：http://127.0.0.1:$BackendPort" -ForegroundColor Cyan
    $backendProcess = Start-Process `
        -FilePath $PythonPath `
        -ArgumentList @("-m", "uvicorn", "app.main:app", "--host", $BackendBindAddress, "--port", $BackendPort) `
        -WorkingDirectory $BackendDir `
        -WindowStyle Hidden `
        -RedirectStandardOutput (Join-Path $LogDir "backend.out.log") `
        -RedirectStandardError (Join-Path $LogDir "backend.err.log") `
        -PassThru
    $backendListenerPid = Wait-ForPort -Port $BackendPort -Launcher $backendProcess

    $frontendListenerPid = $null
    if (-not $SkipFrontend) {
        Write-Host "正在启动前端：http://127.0.0.1:$FrontendPort" -ForegroundColor Cyan
        $originalApiBaseUrl = $env:VITE_API_BASE
        try {
            if (-not [string]::IsNullOrWhiteSpace($ApiBaseUrl)) {
                $env:VITE_API_BASE = $ApiBaseUrl.TrimEnd("/")
            } elseif ($BackendPort -ne 8000) {
                # 自定义后端端口时，为本机访问自动同步前端 API 地址。
                $env:VITE_API_BASE = "http://127.0.0.1:$BackendPort"
            }
            $frontendProcess = Start-Process `
                -FilePath "npm.cmd" `
                -ArgumentList @("run", "dev", "--", "--host", $FrontendBindAddress, "--port", $FrontendPort) `
                -WorkingDirectory $FrontendDir `
                -WindowStyle Hidden `
                -RedirectStandardOutput (Join-Path $LogDir "frontend.out.log") `
                -RedirectStandardError (Join-Path $LogDir "frontend.err.log") `
                -PassThru
        } finally {
            if ($null -eq $originalApiBaseUrl) {
                Remove-Item Env:VITE_API_BASE -ErrorAction SilentlyContinue
            } else {
                $env:VITE_API_BASE = $originalApiBaseUrl
            }
        }
        $frontendListenerPid = Wait-ForPort -Port $FrontendPort -Launcher $frontendProcess
    }

    $state = [ordered]@{
        started_at = (Get-Date).ToString("o")
        project_root = $ProjectRoot
        backend = [ordered]@{
            launcher_pid = $backendProcess.Id
            listener_pid = $backendListenerPid
            bind_address = $BackendBindAddress
            port = $BackendPort
        }
        frontend = if ($SkipFrontend) {
            $null
        } else {
            [ordered]@{
                launcher_pid = $frontendProcess.Id
                listener_pid = $frontendListenerPid
                bind_address = $FrontendBindAddress
                port = $FrontendPort
                api_base_url = if (-not [string]::IsNullOrWhiteSpace($ApiBaseUrl)) {
                    $ApiBaseUrl.TrimEnd("/")
                } elseif ($BackendPort -ne 8000) {
                    "http://127.0.0.1:$BackendPort"
                } else {
                    $null
                }
            }
        }
    }
    $state | ConvertTo-Json -Depth 5 | Set-Content -LiteralPath $StatePath -Encoding UTF8

    Write-Host "项目启动成功。" -ForegroundColor Green
    Write-Host "后端：http://127.0.0.1:$BackendPort"
    if (-not $SkipFrontend) {
        $frontendUrl = "http://127.0.0.1:$FrontendPort"
        Write-Host "前端：$frontendUrl"
        if (-not $NoBrowser) {
            Start-Process $frontendUrl
        }
    }
    Write-Host "日志目录：$LogDir"
    Write-Host "关闭项目：.\stop.ps1"
} catch {
    Write-Host "启动失败：$($_.Exception.Message)" -ForegroundColor Red
    if ($null -ne $frontendProcess) {
        Stop-ProcessTree -RootProcessId $frontendProcess.Id
    }
    if ($null -ne $backendProcess) {
        Stop-ProcessTree -RootProcessId $backendProcess.Id
    }
    Remove-Item -LiteralPath $StatePath -Force -ErrorAction SilentlyContinue
    throw
}