# Modules\SqlService.ps1
# Microsoft SQL Server Management Service Module (.NET System.Data.SqlClient Live & Fallback)

function Build-SqlConnectionString {
    param(
        [string]$Server,
        [string]$AuthType = "Integrated",
        [string]$Username = "",
        [string]$Password = "",
        [string]$DefaultDatabase = "master",
        [int]$Timeout = 10
    )

    $builder = New-Object System.Data.SqlClient.SqlConnectionStringBuilder
    $builder["Data Source"] = $Server
    $builder["Initial Catalog"] = if ([string]::IsNullOrWhiteSpace($DefaultDatabase)) { "master" } else { $DefaultDatabase }
    $builder["Connect Timeout"] = $Timeout
    $builder["Application Name"] = "EnterpriseAdminStudio"

    if ($AuthType -eq "Integrated" -or [string]::IsNullOrWhiteSpace($Username)) {
        $builder["Integrated Security"] = $true
    } else {
        $builder["Integrated Security"] = $false
        $builder["User ID"] = $Username
        $builder["Password"] = $Password
    }

    return $builder.ConnectionString
}

function Test-SqlConnection {
    param(
        [string]$Server,
        [string]$AuthType = "Integrated",
        [string]$Username = "",
        [string]$Password = "",
        [int]$Timeout = 5
    )

    $connStr = Build-SqlConnectionString -Server $Server -AuthType $AuthType -Username $Username -Password $Password -Timeout $Timeout
    $conn = New-Object System.Data.SqlClient.SqlConnection($connStr)

    try {
        $conn.Open()
        $cmd = $conn.CreateCommand()
        $cmd.CommandText = "SELECT @@VERSION AS [Version], SERVERPROPERTY('ProductVersion') AS [ProductVersion], SERVERPROPERTY('Edition') AS [Edition]"
        $reader = $cmd.ExecuteReader()
        if ($reader.Read()) {
            $ver = $reader["ProductVersion"].ToString()
            $edition = $reader["Edition"].ToString()
            return [PSCustomObject]@{
                Success = $true
                Message = "SQL Server 연결 성공 - 버전: $ver ($edition)"
                Version = "$ver ($edition)"
            }
        }
        return [PSCustomObject]@{ Success = $true; Message = "SQL Server 연결 성공" }
    } catch {
        return [PSCustomObject]@{
            Success = $false
            Message = "SQL Server 연결 실패: $($_.Exception.Message)"
        }
    } finally {
        if ($conn.State -eq [System.Data.ConnectionState]::Open) {
            $conn.Close()
        }
        $conn.Dispose()
    }
}

function Get-SqlDatabases {
    param(
        [string]$Filter = "",
        [object]$Config = $null
    )

    $useLive = if ($Config -and $Config.MsSql) { [bool]$Config.MsSql.UseLive } else { $false }

    if ($useLive) {
        $server = $Config.MsSql.Server
        $auth = $Config.MsSql.AuthType
        $user = $Config.MsSql.Username
        $pass = $Config.MsSql.Password
        $timeout = if ($Config.MsSql.ConnectionTimeout) { [int]$Config.MsSql.ConnectionTimeout } else { 10 }

        $connStr = Build-SqlConnectionString -Server $server -AuthType $auth -Username $user -Password $pass -Timeout $timeout
        $conn = New-Object System.Data.SqlClient.SqlConnection($connStr)

        try {
            $conn.Open()
            $cmd = $conn.CreateCommand()
            $cmd.CommandText = @"
SELECT 
    d.name AS DatabaseName,
    d.state_desc AS StateDesc,
    d.recovery_model_desc AS RecoveryModel,
    d.collation_name AS CollationName,
    CAST(ROUND(SUM(CAST(mf.size AS bigint)) * 8.0 / 1024, 1) AS varchar(30)) + ' MB' AS TotalSizeMB,
    ISNULL(CONVERT(varchar(20), MAX(b.backup_finish_date), 120) + ' (' + b.type + ')', '백업 없음') AS LastBackupDate
FROM sys.databases d
LEFT JOIN sys.master_files mf ON d.database_id = mf.database_id
LEFT JOIN msdb.dbo.backupset b ON d.name = b.database_name AND b.type = 'D'
GROUP BY d.name, d.state_desc, d.recovery_model_desc, d.collation_name, b.type
ORDER BY d.name;
"@
            $adapter = New-Object System.Data.SqlClient.SqlDataAdapter($cmd)
            $table = New-Object System.Data.DataTable
            $adapter.Fill($table) | Out-Null

            $list = [System.Collections.Generic.List[PSCustomObject]]::new()
            foreach ($row in $table.Rows) {
                $dbName = $row["DatabaseName"]
                if ([string]::IsNullOrWhiteSpace($Filter) -or $dbName -like "*$Filter*") {
                    $list.Add([PSCustomObject]@{
                        DatabaseName   = $dbName
                        StateDesc      = $row["StateDesc"]
                        TotalSizeMB    = $row["TotalSizeMB"]
                        FreeSpaceMB    = "실시간 계산"
                        RecoveryModel  = $row["RecoveryModel"]
                        CollationName  = $row["CollationName"]
                        LastBackupDate = $row["LastBackupDate"]
                        IsLive         = $true
                    })
                }
            }
            return $list.ToArray()
        } catch {
            Write-Warning "실제 SQL Server 조회 실패: $($_.Exception.Message) (Mock 데이터로 전환합니다)"
        } finally {
            if ($conn.State -eq [System.Data.ConnectionState]::Open) { $conn.Close() }
            $conn.Dispose()
        }
    }

    return Get-SqlSampleDatabases -Filter $Filter
}

function Invoke-SqlBackupAction {
    param(
        [string]$DatabaseName,
        [string]$BackupType = "FULL",
        [object]$Config = $null
    )

    $useLive = if ($Config -and $Config.MsSql) { [bool]$Config.MsSql.UseLive } else { $false }

    if ($useLive) {
        $server = $Config.MsSql.Server
        $auth = $Config.MsSql.AuthType
        $user = $Config.MsSql.Username
        $pass = $Config.MsSql.Password
        $backupDir = if ($Config.MsSql.BackupDirectory) { $Config.MsSql.BackupDirectory } else { "C:\Backups" }

        if (-not (Test-Path $backupDir)) {
            New-Item -ItemType Directory -Path $backupDir -Force | Out-Null
        }

        $timeStamp = (Get-Date).ToString("yyyyMMdd_HHmmss")
        $fileName = "$DatabaseName`_$timeStamp.bak"
        $targetPath = Join-Path $backupDir $fileName

        $connStr = Build-SqlConnectionString -Server $server -AuthType $auth -Username $user -Password $pass -Timeout 30
        $conn = New-Object System.Data.SqlClient.SqlConnection($connStr)

        try {
            $conn.Open()
            $cmd = $conn.CreateCommand()
            $cmd.CommandTimeout = 300 # 백업은 5분 타임아웃
            $cmd.CommandText = "BACKUP DATABASE [$DatabaseName] TO DISK = N'$targetPath' WITH INIT, STATS = 10, NAME = N'$DatabaseName-Full Backup'"
            $cmd.ExecuteNonQuery() | Out-Null

            return [PSCustomObject]@{
                Success = $true
                Database = $DatabaseName
                BackupPath = $targetPath
                Message = "실제 SQL Server 데이터베이스 [$DatabaseName] 백업이 완료되었습니다.`n저장 경로: $targetPath"
            }
        } catch {
            return [PSCustomObject]@{
                Success = $false
                Database = $DatabaseName
                Message = "SQL 백업 실패: $($_.Exception.Message)"
            }
        } finally {
            if ($conn.State -eq [System.Data.ConnectionState]::Open) { $conn.Close() }
            $conn.Dispose()
        }
    }

    return [PSCustomObject]@{
        Success = $true
        Database = $DatabaseName
        BackupPath = "\\backup-nas.corp.local\sqlbackups\$DatabaseName-$((Get-Date).ToString('yyyyMMdd_HHmmss')).bak"
        Message = "[데모 모드] 데이터베이스 [$DatabaseName]의 $BackupType 백업이 가상 완료되었습니다."
    }
}

function Invoke-SqlQuerySnippet {
    param(
        [string]$Query,
        [object]$Config = $null
    )

    $useLive = if ($Config -and $Config.MsSql) { [bool]$Config.MsSql.UseLive } else { $false }

    if ($useLive) {
        $server = $Config.MsSql.Server
        $auth = $Config.MsSql.AuthType
        $user = $Config.MsSql.Username
        $pass = $Config.MsSql.Password

        $connStr = Build-SqlConnectionString -Server $server -AuthType $auth -Username $user -Password $pass -Timeout 15
        $conn = New-Object System.Data.SqlClient.SqlConnection($connStr)

        try {
            $conn.Open()
            $cmd = $conn.CreateCommand()
            $cmd.CommandText = $Query
            $adapter = New-Object System.Data.SqlClient.SqlDataAdapter($cmd)
            $table = New-Object System.Data.DataTable
            $adapter.Fill($table) | Out-Null

            $sw = [System.IO.StringWriter]::new()
            $table | Format-Table -AutoSize | Out-String | ForEach-Object { $sw.WriteLine($_) }
            
            return [PSCustomObject]@{
                Success = $true
                RowCount = $table.Rows.Count
                Output = "(성공: $($table.Rows.Count)개 행 반환됨 - $((Get-Date).ToString('HH:mm:ss')))`n$($sw.ToString())"
            }
        } catch {
            return [PSCustomObject]@{
                Success = $false
                RowCount = 0
                Output = "(오류 발생)`n$($_.Exception.Message)"
            }
        } finally {
            if ($conn.State -eq [System.Data.ConnectionState]::Open) { $conn.Close() }
            $conn.Dispose()
        }
    }

    return [PSCustomObject]@{
        Success = $true
        RowCount = 10
        Output = "(데모 모드 성공: 10개 행 반환됨 - $((Get-Date).ToString('HH:mm:ss')))`n1. tbl_Users (Row: 14,200)`n2. tbl_AuditLogs (Row: 240,119)`n3. tbl_Orders (Row: 82,900)"
    }
}

function Get-SqlSampleDatabases {
    param([string]$Filter = "")

    $databases = @(
        [PSCustomObject]@{
            DatabaseName   = "ERP_PRODUCTION"
            StateDesc      = "ONLINE"
            TotalSizeMB    = "56,370 MB"
            FreeSpaceMB    = "6,410 MB"
            RecoveryModel  = "FULL"
            CollationName  = "Korean_Wansung_CI_AS"
            LastBackupDate = "2026-10-20 02:00:15 (Full)"
            IsLive         = $false
        },
        [PSCustomObject]@{
            DatabaseName   = "HR_PORTAL_DB"
            StateDesc      = "ONLINE"
            TotalSizeMB    = "12,450 MB"
            FreeSpaceMB    = "2,120 MB"
            RecoveryModel  = "FULL"
            CollationName  = "Korean_Wansung_CI_AS"
            LastBackupDate = "2026-10-20 02:30:00 (Full)"
            IsLive         = $false
        },
        [PSCustomObject]@{
            DatabaseName   = "WAREHOUSE_ANALYTICS"
            StateDesc      = "ONLINE"
            TotalSizeMB    = "184,000 MB"
            FreeSpaceMB    = "18,900 MB"
            RecoveryModel  = "SIMPLE"
            CollationName  = "Korean_Wansung_CI_AS"
            LastBackupDate = "2026-10-19 23:00:12 (Full)"
            IsLive         = $false
        },
        [PSCustomObject]@{
            DatabaseName   = "DEV_STAGING_TEST"
            StateDesc      = "ONLINE"
            TotalSizeMB    = "4,200 MB"
            FreeSpaceMB    = "850 MB"
            RecoveryModel  = "SIMPLE"
            CollationName  = "Korean_Wansung_CI_AS"
            LastBackupDate = "2026-10-18 10:15:00 (Full)"
            IsLive         = $false
        },
        [PSCustomObject]@{
            DatabaseName   = "ARCHIVE_2025"
            StateDesc      = "READ_ONLY"
            TotalSizeMB    = "92,500 MB"
            FreeSpaceMB    = "45 MB"
            RecoveryModel  = "SIMPLE"
            CollationName  = "Korean_Wansung_CI_AS"
            LastBackupDate = "2026-01-01 00:00:00 (Full)"
            IsLive         = $false
        }
    )

    if ([string]::IsNullOrWhiteSpace($Filter)) {
        return $databases
    } else {
        return @($databases | Where-Object {
            $_.DatabaseName -like "*$Filter*" -or
            $_.StateDesc -like "*$Filter*"
        })
    }
}