[CmdletBinding()]
param(
    [switch]$DebugMode
)

Set-StrictMode -Version Latest
$ErrorActionPreference = 'Stop'

function Get-YoungestTimestamp {
    param(
        [Parameter(Mandatory)] [string]$FolderPath
    )
    $files = Get-ChildItem -LiteralPath $FolderPath -Recurse -File -ErrorAction SilentlyContinue |
        Where-Object { $_.FullName -notlike '*\_archive\*' }
    $young = $files | Sort-Object LastWriteTime -Descending | Select-Object -First 1 -ExpandProperty LastWriteTime
    if (-not $young) { return [datetime]::Parse('1900-01-01') }
    return $young
}

try {
    $root = (Get-Location).ProviderPath
    $currentDir = Join-Path $root '_CURRENT'
    if (-not (Test-Path -LiteralPath $currentDir)) {
        New-Item -ItemType Directory -Path $currentDir -Force | Out-Null
    }

         $logFile = Join-Path $currentDir '_UpdateSequences.log'

    "[$(Get-Date -Format 'yyyy-MM-dd HH:mm:ss')] === UpdateSequences (ps1) started in '$root' ===" | Add-Content -LiteralPath $logFile

    $dailyDirs = Get-ChildItem -LiteralPath $root -Directory -Filter 'daily_*' | Where-Object { $_.Name -ne '_archive' }

    $mapDaily = @{}
    $dailiesScanned = 0
    foreach ($d in $dailyDirs) {
        $dailiesScanned++
        $seqDirs = @(Get-ChildItem -LiteralPath $d.FullName -Directory | Where-Object { $_.Name -ne '_archive' })
        if ($seqDirs.Count -eq 0) { $seqDirs = @($d) }
        foreach ($s in $seqDirs) {
            if (-not (Test-Path -LiteralPath $s.FullName)) { continue }
            $young = Get-YoungestTimestamp -FolderPath $s.FullName
            $filesCount = @(Get-ChildItem -LiteralPath $s.FullName -Recurse -File -ErrorAction SilentlyContinue | Where-Object { $_.FullName -notlike '*\_archive\*' }).Count
            $seqName = $s.Name
            $cand = [pscustomobject]@{
                Seq        = $seqName
                SrcFull    = $s.FullName
                Young      = $young
                FilesCount = $filesCount
            }
            if ($mapDaily.ContainsKey($seqName)) {
                if ($mapDaily[$seqName].Young -lt $young) { $mapDaily[$seqName] = $cand }
            } else {
                $mapDaily[$seqName] = $cand
            }
        }
    }

    $mapCurrent = @{}
    if (Test-Path -LiteralPath $currentDir) {
        foreach ($c in Get-ChildItem -LiteralPath $currentDir -Directory | Where-Object { $_.Name -ne '_archive' }) {
            $mapCurrent[$c.Name] = Get-YoungestTimestamp -FolderPath $c.FullName
        }
    }

    $lines = @()
    $lines += "[MAPCOUNT]|count=$($mapDaily.Count)"
    $total = 0
    $toCopy = 0
    foreach ($k in $mapDaily.Keys) {
        $total++
        $d = $mapDaily[$k]
        $curYoung = if ($mapCurrent.ContainsKey($k)) { $mapCurrent[$k] } else { [datetime]::Parse('1900-01-01') }
        if ($d.Young -gt $curYoung) {
            $toCopy++
            $lines += "[COPY]|$($d.SrcFull)|$($d.Seq)|files=$($d.FilesCount)|young=$($d.Young.ToString('s'))"
        } else {
            $lines += "[SKIP]|$($d.SrcFull)|$($d.Seq)|reason=notNewer|srcYoung=$($d.Young.ToString('s'))|curYoung=$($curYoung.ToString('s'))"
        }
    }
         $lines += "[META]|dailiesScanned=$dailiesScanned|sequencesTotal=$total|toCopy=$toCopy"
     
     # Print plan to console instead of writing to file
     Write-Host "=== UPDATE PLAN ===" -ForegroundColor Cyan
     foreach ($line in $lines) {
         if ($line -like '[COPY]*') {
             Write-Host $line -ForegroundColor Green
         } elseif ($line -like '[SKIP]*') {
             Write-Host $line -ForegroundColor Yellow
         } else {
             Write-Host $line -ForegroundColor White
         }
     }
     Write-Host "==================" -ForegroundColor Cyan

    $sequencesMirrored = 0
    $mirrorFailures = 0
    foreach ($line in $lines) {
        if ($line.StartsWith('[COPY]')) {
            $parts = $line -split '\|'
            $srcFull = $parts[1]
            $seqName = $parts[2]
            $dstAbs = Join-Path $currentDir $seqName
            if (-not (Test-Path -LiteralPath $dstAbs)) { New-Item -ItemType Directory -Path $dstAbs -Force | Out-Null }
            "[$(Get-Date -Format 'yyyy-MM-dd HH:mm:ss')] Mirror: '$srcFull' -> '$dstAbs'" | Add-Content -LiteralPath $logFile
            $args = @(
                $srcFull,
                $dstAbs,
                '/MIR','/MT:8','/R:1','/W:1','/COPY:DAT','/DCOPY:DAT','/FFT','/NFL','/NDL','/NP','/NJH','/NJS','/XD','_archive'
            )
            $null = & robocopy @args 2>&1 | Add-Content -LiteralPath $logFile
            $rc = $LASTEXITCODE
            if ($rc -lt 8) {
                $sequencesMirrored++
                "[$(Get-Date -Format 'yyyy-MM-dd HH:mm:ss')]   OK rc=$rc" | Add-Content -LiteralPath $logFile
            } else {
                $mirrorFailures++
                "[$(Get-Date -Format 'yyyy-MM-dd HH:mm:ss')]   ERROR rc=$rc" | Add-Content -LiteralPath $logFile
            }
        }
    }

         # Print summary report to console
     Write-Host "=== SUMMARY REPORT ===" -ForegroundColor Magenta
     Write-Host "Dailies scanned: $dailiesScanned" -ForegroundColor White
     Write-Host "Sequences found: $total" -ForegroundColor White
     Write-Host "Planned copies: $toCopy" -ForegroundColor Green
     Write-Host "Completed OK: $sequencesMirrored" -ForegroundColor Green
     Write-Host "Completed FAIL: $mirrorFailures" -ForegroundColor Red
     
     # Summarize skipped sequences
     $skippedLines = @()
     foreach ($line in $lines) {
         if ($line.StartsWith('[SKIP]')) {
             $skippedLines += $line
         }
     }
     if ($skippedLines.Count -gt 0) {
         Write-Host "`n=== SKIPPED SEQUENCES ===" -ForegroundColor Yellow
         $skippedByReason = @{}
         foreach ($skip in $skippedLines) {
             $parts = $skip -split '\|'
             $reason = $parts[3]
             $seqName = $parts[2]
             if (-not $skippedByReason.ContainsKey($reason)) {
                 $skippedByReason[$reason] = @()
             }
             $skippedByReason[$reason] += $seqName
         }
         
         foreach ($reason in $skippedByReason.Keys) {
             $seqs = $skippedByReason[$reason]
             Write-Host "$reason ($($seqs.Count) sequences):" -ForegroundColor Yellow
             foreach ($seq in $seqs | Sort-Object) {
                 Write-Host "  - $seq" -ForegroundColor White
             }
         }
         Write-Host "========================" -ForegroundColor Yellow
     }
     Write-Host "=====================" -ForegroundColor Magenta

    "[$(Get-Date -Format 'yyyy-MM-dd HH:mm:ss')] === UpdateSequences (ps1) completed (d=$dailiesScanned seq=$total ok=$sequencesMirrored fail=$mirrorFailures) ===" | Add-Content -LiteralPath $logFile

         Write-Host "@$logFile"
    exit 0
}
catch {
    $root = (Get-Location).ProviderPath
    $currentDir = Join-Path $root '_CURRENT'
    if (-not (Test-Path -LiteralPath $currentDir)) {
        New-Item -ItemType Directory -Path $currentDir -Force | Out-Null
    }
    $planFile = Join-Path $currentDir '_UpdatePlan.txt'
    ($_.Exception | Out-String) | Set-Content -LiteralPath ($planFile + '.error.txt') -Encoding ASCII
    Write-Host "ERROR: $_"
    exit 1
}