#Requires -Version 5.1
<#
.SYNOPSIS
    独立备份页面：点选磁盘/文件夹，不手输路径。只监听 127.0.0.1。
#>
$ErrorActionPreference = "Stop"
$RootDir = Split-Path -Parent $MyInvocation.MyCommand.Path
$HtmlFile = Join-Path $RootDir "backup-ui.html"
$BackupScript = Join-Path $RootDir "backup-db.ps1"
$Port = 18765
$Url = $null
$listener = $null

. (Join-Path $RootDir "db-config.ps1")

if (-not (Test-Path $HtmlFile)) { throw "找不到 backup-ui.html" }
if (-not (Test-Path $BackupScript)) { throw "找不到 backup-db.ps1" }

Add-Type -AssemblyName System.Windows.Forms
if (-not ("MesFolderPicker" -as [type])) {
    Add-Type -ReferencedAssemblies System.Windows.Forms,System.Drawing -TypeDefinition @"
using System;
using System.Runtime.InteropServices;
using System.Threading;
using System.Windows.Forms;

public static class MesFolderPicker {
    [DllImport("user32.dll")] static extern bool SetForegroundWindow(IntPtr hWnd);
    [DllImport("user32.dll")] static extern bool ShowWindow(IntPtr hWnd, int nCmdShow);
    [DllImport("user32.dll")] static extern IntPtr GetForegroundWindow();
    [DllImport("user32.dll")] static extern uint GetWindowThreadProcessId(IntPtr hWnd, IntPtr processId);
    [DllImport("kernel32.dll")] static extern uint GetCurrentThreadId();
    [DllImport("user32.dll")] static extern bool AttachThreadInput(uint idAttach, uint idAttachTo, bool fAttach);
    [DllImport("user32.dll")] static extern bool BringWindowToTop(IntPtr hWnd);

    public static string Pick(string description) {
        string selected = null;
        Thread t = new Thread(delegate() {
            Form form = new Form();
            form.Text = "MES Backup - Select Folder";
            form.TopMost = true;
            form.ShowInTaskbar = true;
            form.StartPosition = FormStartPosition.CenterScreen;
            form.Width = 420;
            form.Height = 90;
            form.FormBorderStyle = FormBorderStyle.FixedToolWindow;
            form.MinimizeBox = false;
            form.MaximizeBox = false;
            form.Show();
            form.WindowState = FormWindowState.Normal;
            form.Activate();
            ForceForeground(form.Handle);
            Application.DoEvents();

            FolderBrowserDialog dlg = new FolderBrowserDialog();
            dlg.Description = description;
            dlg.ShowNewFolderButton = true;
            dlg.RootFolder = Environment.SpecialFolder.MyComputer;
            DialogResult r = dlg.ShowDialog(form);
            if (r == DialogResult.OK) {
                selected = dlg.SelectedPath;
            }
            form.Close();
            form.Dispose();
        });
        t.SetApartmentState(ApartmentState.STA);
        t.Start();
        t.Join();
        return selected;
    }

    static void ForceForeground(IntPtr hwnd) {
        IntPtr fg = GetForegroundWindow();
        uint fgThread = GetWindowThreadProcessId(fg, IntPtr.Zero);
        uint thisThread = GetCurrentThreadId();
        if (fgThread != thisThread) {
            AttachThreadInput(thisThread, fgThread, true);
        }
        ShowWindow(hwnd, 9);
        BringWindowToTop(hwnd);
        SetForegroundWindow(hwnd);
        if (fgThread != thisThread) {
            AttachThreadInput(thisThread, fgThread, false);
        }
    }
}
"@
}

$State = [hashtable]::Synchronized(@{
    Running   = $false
    Log       = New-Object System.Collections.ArrayList
    Result    = ""
    Error     = ""
    Path      = ""
    StartedAt = ""
    EndedAt   = ""
    Proc      = $null
    OutFile   = ""
    DbBytes   = 0
})

function Add-UiLog {
    param([string]$Text)
    if ([string]::IsNullOrWhiteSpace($Text)) { return }
    [void]$State.Log.Add($Text)
    if ($State.Log.Count -gt 800) {
        $State.Log.RemoveRange(0, 200)
    }
}

function Get-SafePath {
    param([string]$Path)
    if ([string]::IsNullOrWhiteSpace($Path)) { throw "请先选择保存位置" }
    $p = $Path.Trim().Trim('"')
    if ($p -notmatch '^[A-Za-z]:\\') { throw "只允许本机磁盘路径" }
    $full = [System.IO.Path]::GetFullPath($p)
    if ($full -match '^[A-Za-z]:\\?$') {
        return ($full.Substring(0, 1).ToUpper() + ":\")
    }
    return $full.TrimEnd("\")
}

$script:MysqlToolCache = @{}

function Find-MysqlTool {
    param([string]$Name)
    if ($script:MysqlToolCache.ContainsKey($Name)) { return $script:MysqlToolCache[$Name] }
    $cmd = Get-Command $Name -ErrorAction SilentlyContinue
    if ($cmd -and $cmd.Source) {
        $script:MysqlToolCache[$Name] = $cmd.Source
        return $cmd.Source
    }
    $candidates = New-Object System.Collections.Generic.List[string]
    foreach ($root in @(
        "C:\Program Files\MySQL",
        "C:\Program Files (x86)\MySQL",
        "C:\mysql",
        "D:\MySQL",
        "E:\MySQL",
        "C:\Program Files\MariaDB"
    )) {
        if (-not (Test-Path $root)) { continue }
        Get-ChildItem -Path $root -Directory -ErrorAction SilentlyContinue | ForEach-Object {
            $direct = Join-Path $_.FullName ("bin\{0}.exe" -f $Name)
            $candidates.Add($direct)
            Get-ChildItem -Path $_.FullName -Directory -ErrorAction SilentlyContinue | ForEach-Object {
                $candidates.Add((Join-Path $_.FullName ("bin\{0}.exe" -f $Name)))
            }
        }
    }
    foreach ($p in $candidates) {
        if (Test-Path -LiteralPath $p) {
            $script:MysqlToolCache[$Name] = $p
            return $p
        }
    }
    return $null
}

function Get-DbSizeBytes {
    try {
        $cfg = Read-MesDbConfig
        $mysql = Find-MysqlTool "mysql"
        if (-not $mysql) { return 0 }
        $cnf = Join-Path $env:TEMP ("mes_ui_size_{0}.cnf" -f $PID)
        Write-MesMysqlCnf -Config $cfg -CnfPath $cnf
        $sql = "SELECT IFNULL(SUM(data_length+index_length),0) FROM information_schema.tables WHERE table_schema='$($cfg.database)'"
        $out = & $mysql "--defaults-extra-file=$cnf" "--connect-timeout=3" -N -s -e $sql 2>$null
        Remove-Item $cnf -Force -ErrorAction SilentlyContinue
        $n = 0
        [void][int64]::TryParse(($out | Out-String).Trim(), [ref]$n)
        return $n
    } catch {
        return 0
    }
}

function Test-MesMysqlConn {
    param($Config)
    $cfg = ConvertTo-MesDbConfig -InputObject $Config
    $mysql = Find-MysqlTool "mysql"
    if (-not $mysql) { throw "找不到 mysql.exe，请安装 MySQL 客户端" }
    $cnf = Join-Path $env:TEMP ("mes_ui_test_{0}.cnf" -f $PID)
    Write-MesMysqlCnf -Config $cfg -CnfPath $cnf
    try {
        $out = & $mysql "--defaults-extra-file=$cnf" "--connect-timeout=5" -N -s -e "SELECT 1" 2>&1
        if ($LASTEXITCODE -ne 0) {
            throw ("连接失败: {0}" -f ($out | Out-String).Trim())
        }
    } finally {
        Remove-Item $cnf -Force -ErrorAction SilentlyContinue
    }
    return $cfg
}

function Get-DriveList {
    $list = New-Object System.Collections.Generic.List[object]
    foreach ($root in [System.IO.Directory]::GetLogicalDrives()) {
        if ($root -match '^[AB]:\\$') { continue }
        $letter = $root.Substring(0, 2).ToUpper()
        $list.Add([ordered]@{
            letter     = $letter
            path       = $root
            name       = $letter
            type       = "磁盘"
            removable  = $false
            ready      = $true
            sizeGB     = 0
            freeGB     = 0
            freeBytes  = 0
        })
    }
    return $list
}

function Get-FolderList {
    param([string]$Path)
    $full = Get-SafePath $Path
    if (-not (Test-Path -LiteralPath $full)) { throw "路径不存在，请确认已插入磁盘" }
    $parent = [System.IO.Path]::GetDirectoryName($full)
    $folders = New-Object System.Collections.Generic.List[object]
    Get-ChildItem -LiteralPath $full -Directory -Force -ErrorAction SilentlyContinue |
        Select-Object -First 80 |
        ForEach-Object {
            $folders.Add([ordered]@{ name = $_.Name; path = $_.FullName })
        }
    $pathOut = $full
    if (-not $pathOut.EndsWith("\")) { $pathOut += "\" }
    return [ordered]@{
        path    = $pathOut
        parent  = $parent
        folders = $folders
    }
}

function Get-FreeBytes {
    param([string]$Path)
    try {
        $full = Get-SafePath $Path
        $root = [System.IO.Path]::GetPathRoot($full)
        $di = New-Object System.IO.DriveInfo ($root)
        if ($di.IsReady) { return [int64]$di.AvailableFreeSpace }
    } catch { }
    return 0
}

function Show-FolderPicker {
    return [MesFolderPicker]::Pick("选择备份文件保存位置（可选手动插入的 U 盘或移动硬盘）")
}

function Get-WrittenBackup {
    $info = [ordered]@{ bytes = 0; name = ""; doneBytes = 0 }
    $dir = $State.Path
    if (-not $dir -or -not (Test-Path -LiteralPath $dir)) { return $info }
    $files = @(Get-ChildItem -LiteralPath $dir -File -ErrorAction SilentlyContinue |
        Where-Object { $_.Name -like "mes_cloud_*.sql.gz*" } |
        Sort-Object LastWriteTime -Descending)
    if ($files.Count -gt 0) {
        $final = @($files | Where-Object { $_.Name -notlike "*.tmp" }) | Select-Object -First 1
        $pick = if ($final) { $final } else { $files[0] }
        $info.name = $pick.Name
        $info.bytes = [int64]$pick.Length
        if ($pick.Name -notlike "*.tmp") {
            $info.doneBytes = [int64]$pick.Length
        }
    }
    return $info
}

function Read-JsonBody {
    param($Request)
    $reader = New-Object System.IO.StreamReader($Request.InputStream, [System.Text.Encoding]::UTF8)
    try {
        $raw = $reader.ReadToEnd()
    } finally {
        $reader.Dispose()
    }
    if ([string]::IsNullOrWhiteSpace($raw)) { return $null }
    return $raw | ConvertFrom-Json
}

function Send-Bytes {
    param($Response, [byte[]]$Bytes, [string]$ContentType, [int]$Status = 200)
    $Response.StatusCode = $Status
    $Response.ContentType = $ContentType
    $Response.Headers["Cache-Control"] = "no-store"
    $Response.ContentLength64 = $Bytes.Length
    $Response.OutputStream.Write($Bytes, 0, $Bytes.Length)
    $Response.OutputStream.Close()
}

function Send-Json {
    param($Response, $Object, [int]$Status = 200)
    $json = $Object | ConvertTo-Json -Depth 8 -Compress
    $bytes = [System.Text.Encoding]::UTF8.GetBytes($json)
    Send-Bytes -Response $Response -Bytes $bytes -ContentType "application/json; charset=utf-8" -Status $Status
}

function Send-Html {
    param($Response)
    $bytes = [System.IO.File]::ReadAllBytes($HtmlFile)
    Send-Bytes -Response $Response -Bytes $bytes -ContentType "text/html; charset=utf-8"
}

function Start-BackupJob {
    param([string]$TargetDir, [int]$KeepDays)
    if ($State.Running) { throw "已有备份正在进行" }
    $dir = Get-SafePath $TargetDir
    $free = Get-FreeBytes -Path $dir
    $dbBytes = Get-DbSizeBytes
    $State.DbBytes = $dbBytes
    # gzip 后通常小于库文件，但 SQL 文本可能接近库大小；预留 1.2 倍库容量
    if ($dbBytes -gt 0 -and $free -gt 0 -and $free -lt [int64]($dbBytes * 1.2)) {
        $needGB = [math]::Round($dbBytes * 1.2 / 1GB, 2)
        $freeGB = [math]::Round($free / 1GB, 2)
        throw ("目标盘剩余空间不足：约需 {0} GB，当前剩余 {1} GB。请换更大的 U 盘/硬盘。" -f $needGB, $freeGB)
    }
    if (-not (Test-Path -LiteralPath $dir)) {
        New-Item -ItemType Directory -Path $dir -Force | Out-Null
    }
    $outFile = Join-Path $env:TEMP ("mes_backup_ui_{0}.log" -f (Get-Date -Format "yyyyMMddHHmmss"))
    $errFile = $outFile + ".err"
    if (Test-Path $outFile) { Remove-Item $outFile -Force }
    if (Test-Path $errFile) { Remove-Item $errFile -Force }

    $arg = '-NoProfile -ExecutionPolicy Bypass -File "{0}" -BackupDir "{1}" -KeepDaysParam {2}' -f $BackupScript, $dir, $KeepDays
    $proc = Start-Process -FilePath "powershell.exe" -ArgumentList $arg -PassThru -WindowStyle Hidden `
        -RedirectStandardOutput $outFile -RedirectStandardError $errFile

    $State.Running = $true
    $State.Result = ""
    $State.Error = ""
    $State.Path = $dir
    $State.StartedAt = (Get-Date -Format "yyyy-MM-dd HH:mm:ss")
    $State.EndedAt = ""
    $State.Proc = $proc
    $State.OutFile = $outFile
    $State.Log.Clear()
    Add-UiLog ("开始备份到: {0}" -f $dir)
    if ($dbBytes -gt 0) {
        Add-UiLog ("库数据约 {0} GB，采用边导出边压缩，请耐心等待，勿拔盘" -f ([math]::Round($dbBytes / 1GB, 2)))
    }
}

function Read-LogFiles {
    $lines = New-Object System.Collections.ArrayList
    foreach ($f in @($State.OutFile, ($State.OutFile + ".err"))) {
        if (-not $f -or -not (Test-Path $f)) { continue }
        $text = $null
        foreach ($encName in @("UTF8", "Default")) {
            try {
                $enc = [System.Text.Encoding]::$encName
                $text = [System.IO.File]::ReadAllText($f, $enc)
                if ($text -and $text.IndexOf([char]0xFFFD) -lt 0) { break }
            } catch { }
        }
        if ($text) {
            foreach ($line in ($text -split "`r?`n")) {
                if ($line.Trim() -ne "") { [void]$lines.Add($line) }
            }
        }
    }
    return $lines
}

function Test-BackupFileOk {
    $dir = $State.Path
    if (-not $dir -or -not (Test-Path -LiteralPath $dir)) { return $false }
    $started = $null
    try {
        if ($State.StartedAt) { $started = [datetime]::Parse($State.StartedAt) }
    } catch { }
    $gz = Get-ChildItem -LiteralPath $dir -File -Filter "mes_cloud_*.sql.gz" -ErrorAction SilentlyContinue |
        Sort-Object LastWriteTime -Descending |
        Select-Object -First 1
    if ($null -eq $gz -or $gz.Length -le 100) { return $false }
    if ($started -and $gz.LastWriteTime -lt $started.AddMinutes(-2)) { return $false }
    return $true
}

function Update-BackupState {
    if (-not $State.Running) { return }
    $proc = $State.Proc
    $lines = Read-LogFiles
    if ($lines.Count -gt 0) {
        $State.Log.Clear()
        foreach ($line in $lines) { [void]$State.Log.Add($line) }
    }
    if ($null -eq $proc) { return }
    try { $proc.Refresh() } catch { }
    try { $exited = $proc.HasExited } catch { $exited = $true }
    if (-not $exited) { return }
    try { $proc.WaitForExit(1000) } catch { }
    $code = $null
    try { $code = $proc.ExitCode } catch { $code = $null }
    $State.Running = $false
    $State.EndedAt = (Get-Date -Format "yyyy-MM-dd HH:mm:ss")
    $State.Proc = $null
    $fileOk = Test-BackupFileOk
    # Start-Process 有时读不到 ExitCode（界面显示「退出码」后面空白）；有新生成的 .gz 即视为成功
    $success = ($code -eq 0) -or $fileOk
    if ($success) {
        $State.Result = "ok"
        $State.Error = ""
        Add-UiLog "备份完成"
    } else {
        $State.Result = "error"
        $codeText = if ($null -eq $code) { "未知" } else { [string]$code }
        $State.Error = "备份失败，退出码 $codeText"
        Add-UiLog $State.Error
    }
}

$listener = $null
$started = $false
$lastError = $null
foreach ($tryPort in 18765..18785) {
    $tryUrl = "http://127.0.0.1:{0}/" -f $tryPort
    $tryListener = New-Object System.Net.HttpListener
    try {
        $tryListener.Prefixes.Add($tryUrl)
        $tryListener.Start()
        $listener = $tryListener
        $Port = $tryPort
        $Url = $tryUrl
        $started = $true
        break
    } catch {
        $lastError = $_.Exception.Message
        try { $tryListener.Close() } catch { }
    }
}
if (-not $started) {
    throw ("无法启动本机页面，18765-18785 端口都被占用。请先关掉之前打开的备份窗口后再试。详情: {0}" -f $lastError)
}

Write-Host ""
Write-Host ("数据库备份页面已启动（仅本机）: {0}" -f $Url)
if ($Port -ne 18765) {
    Write-Host ("原端口 18765 已被占用，已自动改用 {0}。请先关掉旧的备份窗口，避免开两个。" -f $Port)
}
Write-Host "请在网页点「浏览文件夹」选择 U 盘/硬盘目录，不要手输路径。"
Write-Host "关闭本窗口即停止页面。"
Write-Host ""
Start-Process $Url

try {
while ($listener.IsListening) {
    $ctx = $null
    try {
        $ctx = $listener.GetContext()
        $req = $ctx.Request
        $res = $ctx.Response
        $path = $req.Url.AbsolutePath.TrimEnd("/")
        if ([string]::IsNullOrEmpty($path)) { $path = "/" }

        if ($req.HttpMethod -eq "OPTIONS") {
            $res.StatusCode = 204
            $res.AddHeader("Access-Control-Allow-Origin", "*")
            $res.AddHeader("Access-Control-Allow-Methods", "GET, POST, OPTIONS")
            $res.AddHeader("Access-Control-Allow-Headers", "Content-Type")
            $res.ContentLength64 = 0
            $res.Close()
            continue
        }
        if ($req.HttpMethod -eq "GET" -and ($path -eq "/" -or $path -eq "/index.html")) {
            Send-Html -Response $res
            continue
        }
        if ($req.HttpMethod -eq "GET" -and $path -eq "/api/drives") {
            Send-Json -Response $res -Object ([ordered]@{
                ok     = $true
                drives = @(Get-DriveList)
            })
            continue
        }
        if ($req.HttpMethod -eq "GET" -and $path -eq "/api/dbsize") {
            Send-Json -Response $res -Object ([ordered]@{
                ok      = $true
                dbBytes = [int64](Get-DbSizeBytes)
            })
            continue
        }
        if ($req.HttpMethod -eq "GET" -and $path -eq "/api/folders") {
            $folderPath = ""
            $query = $req.Url.Query.TrimStart("?")
            if ($query) {
                foreach ($pair in $query.Split([char]38)) {
                    $kv = $pair.Split("=", 2)
                    if ($kv.Count -ge 2 -and [uri]::UnescapeDataString($kv[0]) -eq "path") {
                        $folderPath = [uri]::UnescapeDataString(($kv[1] -replace "\+", " "))
                    }
                }
            }
            Send-Json -Response $res -Object ([ordered]@{ ok = $true; data = (Get-FolderList -Path $folderPath) })
            continue
        }
        if ($req.HttpMethod -eq "POST" -and $path -eq "/api/browse") {
            $picked = Show-FolderPicker
            if ([string]::IsNullOrWhiteSpace($picked)) {
                Send-Json -Response $res -Object ([ordered]@{ ok = $true; cancelled = $true })
            } else {
                Send-Json -Response $res -Object ([ordered]@{
                    ok       = $true
                    cancelled = $false
                    path     = $picked
                    freeBytes = [int64](Get-FreeBytes -Path $picked)
                })
            }
            continue
        }
        if ($req.HttpMethod -eq "GET" -and $path -eq "/api/status") {
            Update-BackupState
            $written = Get-WrittenBackup
            Send-Json -Response $res -Object ([ordered]@{
                ok         = $true
                running    = [bool]$State.Running
                result     = $State.Result
                error      = $State.Error
                path       = $State.Path
                startedAt  = $State.StartedAt
                endedAt    = $State.EndedAt
                log        = @($State.Log)
                dbBytes    = [int64]$State.DbBytes
                writtenBytes = [int64]$written.bytes
                fileName   = $written.name
            })
            continue
        }
        if ($req.HttpMethod -eq "GET" -and $path -eq "/api/config") {
            try {
                $cfg = Read-MesDbConfig
            } catch {
                $cfg = Get-DefaultMesDbConfig
            }
            Send-Json -Response $res -Object ([ordered]@{
                ok       = $true
                engine   = "mysql"
                host     = [string]$cfg.host
                port     = [int]$cfg.port
                database = [string]$cfg.database
                user     = [string]$cfg.user
                password = [string]$cfg.password
            })
            continue
        }
        if ($req.HttpMethod -eq "POST" -and $path -eq "/api/config") {
            $body = Read-JsonBody -Request $req
            $cfg = Save-MesDbConfig -Config $body
            Send-Json -Response $res -Object ([ordered]@{
                ok       = $true
                message  = "已保存 MySQL 配置"
                host     = [string]$cfg.host
                port     = [int]$cfg.port
                database = [string]$cfg.database
                user     = [string]$cfg.user
            })
            continue
        }
        if (($req.HttpMethod -eq "GET" -or $req.HttpMethod -eq "POST") -and $path -eq "/api/test") {
            $body = $null
            if ($req.HttpMethod -eq "POST") {
                $body = Read-JsonBody -Request $req
            }
            if ($null -eq $body) {
                $q = $req.Url.Query.TrimStart("?")
                $map = @{}
                if ($q) {
                    foreach ($pair in $q.Split([char]38)) {
                        $kv = $pair.Split("=", 2)
                        if ($kv.Count -ge 2) {
                            $map[[uri]::UnescapeDataString($kv[0])] = [uri]::UnescapeDataString(($kv[1] -replace "\+", " "))
                        }
                    }
                }
                $body = [pscustomobject]@{
                    engine   = "mysql"
                    host     = $map["host"]
                    port     = $map["port"]
                    database = $map["database"]
                    user     = $map["user"]
                    password = $map["password"]
                }
            }
            $cfg = Test-MesMysqlConn -Config $body
            Send-Json -Response $res -Object ([ordered]@{
                ok      = $true
                message = ("MySQL 连接成功: {0}:{1} / {2}" -f $cfg.host, $cfg.port, $cfg.database)
            })
            continue
        }
        if ($req.HttpMethod -eq "POST" -and $path -eq "/api/backup") {
            $body = Read-JsonBody -Request $req
            if ($body -and $body.host) {
                Save-MesDbConfig -Config $body | Out-Null
            }
            $keep = 0
            if ($body -and $null -ne $body.keepDays) { $keep = [int]$body.keepDays }
            Start-BackupJob -TargetDir $body.path -KeepDays $keep
            Send-Json -Response $res -Object ([ordered]@{ ok = $true; message = "已开始备份" })
            continue
        }
        Send-Json -Response $res -Object ([ordered]@{ ok = $false; message = "未找到接口" }) -Status 404
    } catch {
        if ($null -ne $ctx) {
            try {
                Send-Json -Response $ctx.Response -Object ([ordered]@{ ok = $false; message = $_.Exception.Message }) -Status 500
            } catch { }
        }
    }
}
} finally {
    if ($listener) {
        try { $listener.Stop() } catch { }
        try { $listener.Close() } catch { }
    }
}