<#
.SYNOPSIS
  Non-blocking server management script for local-mcp.

.DESCRIPTION
  Manages the local-mcp server process without blocking the terminal.
  The server runs as a detached background process; stdout/stderr are
  written to logs/server.log.

.USAGE
  .\server.ps1 start        # Start (no-op if already running)
  .\server.ps1 stop         # Kill the running server
  .\server.ps1 restart      # Stop then start
  .\server.ps1 status       # Show PID, port state, and tail 20 log lines
  .\server.ps1 logs [N]     # Tail last N lines of the log (default 40)
  .\server.ps1 logs -f      # Follow log live (Ctrl-C to quit)
#>

param(
    [Parameter(Position = 0)]
    [ValidateSet("start", "stop", "restart", "status", "logs")]
    [string]$Command = "status",

    [Parameter(Position = 1)]
    [string]$Arg = ""
)

# ── Paths ─────────────────────────────────────────────────────────────────

$Root     = $PSScriptRoot
$Python   = Join-Path $Root ".venv\Scripts\python.exe"
$Entry    = Join-Path $Root "main.py"
$LogDir   = Join-Path $Root "logs"
$LogOut   = Join-Path $LogDir "server.log"
$LogErr   = Join-Path $LogDir "server.err.log"
$PidFile  = Join-Path $LogDir "server.pid"
$Port     = 8000

# ── Helpers ───────────────────────────────────────────────────────────────

function EnsureLogDir {
    if (-not (Test-Path $LogDir)) {
        New-Item -ItemType Directory -Path $LogDir | Out-Null
    }
}

function GetServerPid {
    # Trust the PID file first; verify the process is actually alive
    if (Test-Path $PidFile) {
        $stored = Get-Content $PidFile -ErrorAction SilentlyContinue
        if ($stored -match '^\d+$') {
            $proc = Get-Process -Id ([int]$stored) -ErrorAction SilentlyContinue
            if ($proc) { return [int]$stored }
        }
        Remove-Item $PidFile -ErrorAction SilentlyContinue
    }

    # Fallback: find python process listening on the port
    $conn = Get-NetTCPConnection -LocalPort $Port -State Listen -ErrorAction SilentlyContinue |
            Select-Object -First 1
    if ($conn) { return $conn.OwningProcess }

    return $null
}

function IsRunning {
    return $null -ne (GetServerPid)
}

function WriteLog([string]$msg, [string]$color = "White") {
    Write-Host $msg -ForegroundColor $color
}

function MergedLogTail([int]$n) {
    # Merge stdout + stderr logs sorted by content order and tail n lines
    $lines = @()
    if (Test-Path $LogOut) { $lines += Get-Content $LogOut -Tail ($n * 2) }
    if (Test-Path $LogErr) { $lines += Get-Content $LogErr -Tail ($n * 2) }
    # Return last $n lines (simple approach — interleaving is approximate)
    $lines | Select-Object -Last $n
}

# ── Commands ──────────────────────────────────────────────────────────────

function Start-Server {
    if (IsRunning) {
        $pid_ = GetServerPid
        WriteLog "Server already running  (PID $pid_  http://localhost:$Port)" "Green"
        return
    }

    if (-not (Test-Path $Python)) {
        WriteLog "ERROR: Python venv not found at $Python" "Red"
        WriteLog "Run: python -m venv .venv && .venv\Scripts\pip install -r requirements.txt" "Yellow"
        exit 1
    }

    EnsureLogDir
    # Stamp both log files so they exist and have a separator
    $stamp = "$(Get-Date -Format 'yyyy-MM-dd HH:mm:ss')  [server.ps1] ---- starting ----"
    Add-Content $LogOut $stamp
    Add-Content $LogErr $stamp

    # Start python with stdout -> LogOut, stderr -> LogErr (separate files required on Windows)
    $proc = Start-Process `
        -FilePath        $Python `
        -ArgumentList    "-u `"$Entry`"" `
        -WorkingDirectory $Root `
        -RedirectStandardOutput $LogOut `
        -RedirectStandardError  $LogErr `
        -WindowStyle     Hidden `
        -PassThru

    $proc.Id | Set-Content $PidFile

    # Wait up to 6 s for the port to open
    $deadline = (Get-Date).AddSeconds(6)
    $ready    = $false
    while ((Get-Date) -lt $deadline) {
        Start-Sleep -Milliseconds 400
        $conn = Get-NetTCPConnection -LocalPort $Port -State Listen -ErrorAction SilentlyContinue
        if ($conn) { $ready = $true; break }
    }

    if ($ready) {
        WriteLog "Server started  (PID $($proc.Id)  http://localhost:$Port)" "Green"
    } else {
        WriteLog "Server process launched (PID $($proc.Id)) but port $Port not yet open." "Yellow"
        WriteLog "Check logs:  .\server.ps1 logs" "Yellow"
    }
}

function Stop-Server {
    $pid_ = GetServerPid
    if (-not $pid_) {
        WriteLog "Server is not running." "Yellow"
        return
    }

    Stop-Process -Id $pid_ -Force -ErrorAction SilentlyContinue
    Remove-Item $PidFile -ErrorAction SilentlyContinue

    # Wait up to 4 s for the port to free
    $deadline = (Get-Date).AddSeconds(4)
    while ((Get-Date) -lt $deadline) {
        Start-Sleep -Milliseconds 300
        $conn = Get-NetTCPConnection -LocalPort $Port -State Listen -ErrorAction SilentlyContinue
        if (-not $conn) { break }
    }

    WriteLog "Server stopped  (was PID $pid_)" "Yellow"
}

function Restart-Server {
    Stop-Server
    Start-Sleep -Milliseconds 500
    Start-Server
}

function Show-Status {
    $pid_ = GetServerPid
    if ($pid_) {
        $proc = Get-Process -Id $pid_ -ErrorAction SilentlyContinue
        $mem  = if ($proc) { "{0:N0} MB" -f ($proc.WorkingSet64 / 1MB) } else { "?" }
        WriteLog ""
        WriteLog "  Status  : RUNNING" "Green"
        WriteLog "  PID     : $pid_"
        WriteLog "  Memory  : $mem"
        WriteLog "  URL     : http://localhost:$Port"
        WriteLog "  Logs    : $LogOut"
        WriteLog "            $LogErr"
    } else {
        WriteLog ""
        WriteLog "  Status  : STOPPED" "Red"
    }

    WriteLog ""
    WriteLog "--- Last 20 log lines (stdout) ---" "DarkGray"
    if (Test-Path $LogOut) {
        Get-Content $LogOut -Tail 20 | ForEach-Object { WriteLog $_ "DarkGray" }
    } else {
        WriteLog "  (no log file yet)" "DarkGray"
    }

    if (Test-Path $LogErr) {
        $errLines = Get-Content $LogErr -Tail 5 | Where-Object { $_ -match "ERROR|Exception|Traceback" }
        if ($errLines) {
            WriteLog ""
            WriteLog "--- Recent errors (stderr) ---" "Red"
            $errLines | ForEach-Object { WriteLog $_ "Red" }
        }
    }
    WriteLog ""
}

function Tail-Logs {
    EnsureLogDir

    if ($Arg -eq "-f") {
        if (-not (Test-Path $LogOut)) {
            WriteLog "No log file yet. Start the server first." "Yellow"
            return
        }
        WriteLog "Following $LogOut  (Ctrl-C to stop)" "Cyan"
        Get-Content $LogOut -Wait -Tail 30
    } else {
        $n = if ($Arg -match '^\d+$') { [int]$Arg } else { 40 }
        WriteLog "--- stdout (last $n lines) ---" "Cyan"
        if (Test-Path $LogOut) { Get-Content $LogOut -Tail $n } else { WriteLog "  (empty)" "DarkGray" }
        WriteLog ""
        WriteLog "--- stderr (last 20 lines) ---" "Yellow"
        if (Test-Path $LogErr) { Get-Content $LogErr -Tail 20 } else { WriteLog "  (empty)" "DarkGray" }
    }
}

# ── Dispatch ──────────────────────────────────────────────────────────────

switch ($Command) {
    "start"   { Start-Server   }
    "stop"    { Stop-Server    }
    "restart" { Restart-Server }
    "status"  { Show-Status    }
    "logs"    { Tail-Logs      }
}