# 构建缓存管理脚本
# 功能：保存和恢复 node_modules 缓存，加速 Docker 构建
# 状态：旧构建缓存方案，不是当前 Git 增量部署的默认前置步骤

param(
    [ValidateSet('save', 'check', 'clean')]
    [string]$Action = 'check'
)

$CacheDir = ".build-cache"
$CacheFile = "$CacheDir/node_modules.tar.gz"
$HashFile = "$CacheDir/package-lock.json.hash"

# 确保缓存目录存在
if (-not (Test-Path $CacheDir)) {
    New-Item -ItemType Directory -Path $CacheDir -Force | Out-Null
}

# 计算 package-lock.json 的哈希值
function Get-PackageLockHash {
    if (Test-Path "package-lock.json") {
        $hash = Get-FileHash "package-lock.json" -Algorithm MD5
        return $hash.Hash
    }
    return $null
}

# 检查缓存是否有效
function Test-CacheValid {
    if (-not (Test-Path $CacheFile)) {
        return $false
    }
    
    if (-not (Test-Path $HashFile)) {
        return $false
    }
    
    $currentHash = Get-PackageLockHash
    $cachedHash = Get-Content $HashFile -Raw
    
    return $currentHash -eq $cachedHash.Trim()
}

# 保存缓存
function Save-Cache {
    Write-Host "📦 保存 node_modules 缓存..." -ForegroundColor Cyan
    
    if (-not (Test-Path "node_modules")) {
        Write-Host "❌ node_modules 不存在，无法保存缓存" -ForegroundColor Red
        return
    }
    
    # 保存哈希值
    $hash = Get-PackageLockHash
    $hash | Out-File $HashFile -Encoding UTF8 -NoNewline
    
    # 压缩 node_modules
    Write-Host "   压缩中（这可能需要 1-2 分钟）..." -ForegroundColor Yellow
    tar -czf $CacheFile node_modules 2>&1 | Out-Null
    
    if ($LASTEXITCODE -eq 0) {
        $size = (Get-Item $CacheFile).Length / 1MB
        Write-Host "✅ 缓存已保存：$([Math]::Round($size, 2)) MB" -ForegroundColor Green
        Write-Host "   哈希值：$hash" -ForegroundColor Gray
    } else {
        Write-Host "❌ 缓存保存失败" -ForegroundColor Red
    }
}

# 检查缓存状态
function Check-Cache {
    Write-Host "🔍 检查构建缓存状态" -ForegroundColor Cyan
    Write-Host ""
    
    $currentHash = Get-PackageLockHash
    Write-Host "当前 package-lock.json 哈希：$currentHash" -ForegroundColor Gray
    
    if (Test-Path $HashFile) {
        $cachedHash = Get-Content $HashFile -Raw
        Write-Host "缓存 package-lock.json 哈希：$($cachedHash.Trim())" -ForegroundColor Gray
    } else {
        Write-Host "缓存 package-lock.json 哈希：不存在" -ForegroundColor Gray
    }
    
    Write-Host ""
    
    if (Test-CacheValid) {
        $size = (Get-Item $CacheFile).Length / 1MB
        Write-Host "✅ 缓存有效（$([Math]::Round($size, 2)) MB）" -ForegroundColor Green
        Write-Host "   构建时将使用缓存，预计时间：10-20 秒" -ForegroundColor Green
    } else {
        if (Test-Path $CacheFile) {
            Write-Host "⚠️  缓存已过期（package-lock.json 已变化）" -ForegroundColor Yellow
        } else {
            Write-Host "⚠️  缓存不存在" -ForegroundColor Yellow
        }
        Write-Host "   构建时将重新下载依赖，预计时间：60-90 秒" -ForegroundColor Yellow
    }
}

# 清理缓存
function Clean-Cache {
    Write-Host "🧹 清理构建缓存" -ForegroundColor Cyan
    
    if (Test-Path $CacheFile) {
        Remove-Item $CacheFile -Force
        Write-Host "✅ 已删除：$CacheFile" -ForegroundColor Green
    }
    
    if (Test-Path $HashFile) {
        Remove-Item $HashFile -Force
        Write-Host "✅ 已删除：$HashFile" -ForegroundColor Green
    }
    
    Write-Host "✅ 缓存已清理" -ForegroundColor Green
}

# 执行操作
switch ($Action) {
    'save' { Save-Cache }
    'check' { Check-Cache }
    'clean' { Clean-Cache }
}