<#
.SYNOPSIS
    Crops video clips using ffmpeg.
.PARAMETER Source
    Source directory containing video files.
.PARAMETER Target
    Target directory for cropped video files.
.DESCRIPTION
    Crops video clips using ffmpeg.
    Supports -WhatIf and -Confirm for safe execution.
#>
[CmdletBinding(SupportsShouldProcess)]
param(
    [Parameter(Mandatory = $false)]
    [string]$Source = '.',

    [Parameter(Mandatory = $false)]
    [string]$Target = '.'
)

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

function Get-VideoInfo {
    param(
        [Parameter(Mandatory = $true)]
        [string]$Path
    )

    $json = & ffprobe -v error -print_format json -show_streams -show_format -- "$Path"
    if ($LASTEXITCODE -ne 0 -or -not $json) {
        throw "ffprobe failed for: $Path"
    }

    $info = $json | ConvertFrom-Json
    $videoStream = $info.streams | Where-Object { $_.codec_type -eq 'video' } | Select-Object -First 1
    if (-not $videoStream) {
        throw "No video stream found in: $Path"
    }

    $audioStream = $info.streams | Where-Object { $_.codec_type -eq 'audio' } | Select-Object -First 1

    # Safe property accessor: returns $null when the property is absent (strict-mode friendly).
    $get = { param($obj, $name) if ($obj -and ($obj.PSObject.Properties.Name -contains $name)) { $obj.$name } else { $null } }

    $rFrameRate = & $get $videoStream 'r_frame_rate'
    $fps = $null
    if ($rFrameRate -and $rFrameRate -match '^(\d+)/(\d+)$') {
        $num = [double]$Matches[1]
        $den = [double]$Matches[2]
        if ($den -ne 0) {
            $fps = $num / $den
        }
    }

    $videoBitRate = & $get $videoStream 'bit_rate'
    $formatBitRate = & $get $info.format 'bit_rate'
    $bitRate = if ($videoBitRate) { $videoBitRate } else { $formatBitRate }

    [pscustomobject]@{
        Path         = $Path
        FileName     = [System.IO.Path]::GetFileName($Path)
        Width        = [int]$videoStream.width
        Height       = [int]$videoStream.height
        Fps          = $fps
        BitRate      = $bitRate
        HasAudio     = [bool]$audioStream
        VideoBitRate = $videoBitRate
    }
}

function Format-Quality {
    param(
        [Parameter(Mandatory = $false)]
        $BitRate
    )

    if (-not $BitRate -or $BitRate -notmatch '^\d+$') {
        return 'unknown'
    }

    $kbps = [math]::Round(([double]$BitRate) / 1000.0)
    return "${kbps}kbps"
}

$sourceFull = (Resolve-Path -LiteralPath $Source).Path
$targetFull = (Resolve-Path -LiteralPath $Target).Path

$BackupRequired = ($sourceFull.TrimEnd('\') -ieq $targetFull.TrimEnd('\'))

$processedCount = 0

$videos = Get-ChildItem -LiteralPath $sourceFull -Filter '*.mp4' -File
foreach ($video in $videos) {
    if ($video.Name -like '*.bak.mp4' -or $video.Name -like '*.skip.mp4') {
        continue
    }

    $inputPath = $video.FullName

    $inInfo = $null
    try {
        $inInfo = Get-VideoInfo -Path $inputPath
    }
    catch {
        Write-Error $_
        throw
    }

    $inRes = "{0}x{1}" -f $inInfo.Width, $inInfo.Height
    $inFpsText = if ($inInfo.Fps) { "{0:0.###}" -f $inInfo.Fps } else { 'unknown' }
    $inQuality = Format-Quality -BitRate $inInfo.BitRate
    $inAudioText = if ($inInfo.HasAudio) { 'yes' } else { 'no' }

    $vf = $null
    if ($inInfo.Width -eq 1920 -and $inInfo.Height -eq 1088) {
        $vf = 'crop=1920:1080:0:4'
    }
    elseif ($inInfo.Width -eq 1280 -and $inInfo.Height -eq 704) {
        $vf = 'scale=-2:720,crop=1280:720:(in_w-1280)/2:(in_h-720)/2'
    }
    elseif ($inInfo.Width -eq 1088 -and $inInfo.Height -eq 1920) {
        $vf = 'crop=1080:1920:4:0'
    }
    elseif ($inInfo.Width -eq 704 -and $inInfo.Height -eq 1280) {
        $vf = 'scale=720:-2,crop=720:1280:(in_w-720)/2:(in_h-1280)/2'
    }
    elseif ($inInfo.Width -eq 832 -and $inInfo.Height -eq 448) {
        $vf = 'scale=-2:480,crop=854:480:(in_w-854)/2:(in_h-480)/2'
    }
    elseif ($inInfo.Width -eq 448 -and $inInfo.Height -eq 832) {
        $vf = 'scale=480:-2,crop=480:854:(in_w-480)/2:(in_h-854)/2'
    }

    if (-not $vf) {
        Write-Host "Skipping: $($inInfo.FileName) (resolution $inRes)"
        continue
    }

    Write-Host "Input : Filename=$($inInfo.FileName) Resolution=$inRes FPS=$inFpsText Quality=$inQuality Audio=$inAudioText"

    if ($BackupRequired) {
        $backupPath = Join-Path $video.DirectoryName ($video.BaseName + '.bak' + $video.Extension)
        if ($PSCmdlet.ShouldProcess($backupPath, 'Create backup of original video')) {
            Copy-Item -LiteralPath $inputPath -Destination $backupPath -Force
        }
    }

    $outCropPath = Join-Path $targetFull ($video.BaseName + '.crop.mp4')
    $outFinalPath = Join-Path $targetFull $video.Name

    $ffArgs = @(
        '-y',
        '-i', $inputPath,
        '-vf', $vf
    )

    if ($inInfo.HasAudio) {
        $ffArgs += @('-c:a', 'copy')
    }
    else {
        $ffArgs += @('-an')
    }

    if ($inInfo.VideoBitRate -and $inInfo.VideoBitRate -match '^\d+$') {
        $ffArgs += @('-b:v', $inInfo.VideoBitRate)
    }
    else {
        $ffArgs += @('-crf', '8', '-preset', 'slow')
    }

    $ffArgs += @($outCropPath)

    if ($PSCmdlet.ShouldProcess($outCropPath, 'Crop video with ffmpeg')) {
        $ffmpegOutput = & ffmpeg @ffArgs 2>&1
        $ffmpegExit = $LASTEXITCODE

        if ($ffmpegExit -ne 0) {
            if (Test-Path -LiteralPath $outCropPath) {
                Remove-Item -LiteralPath $outCropPath -Force -ErrorAction SilentlyContinue
            }

            $ffmpegOutput | ForEach-Object { Write-Error $_ }
            Write-Error "ffmpeg failed while cropping: $($inInfo.FileName)"
            Write-Host "ffmpeg $($ffArgs -join ' ')"
            exit 1
        }

        if (($BackupRequired) -and ($PSCmdlet.ShouldProcess($inputPath, 'Remove original video after backup'))) {
            Remove-Item -LiteralPath $inputPath -Force
        }

        if ((Test-Path -LiteralPath $outFinalPath) -and ($PSCmdlet.ShouldProcess($outFinalPath, 'Remove existing output file'))) {
            Remove-Item -LiteralPath $outFinalPath -Force
        }
        if ($PSCmdlet.ShouldProcess("$outCropPath -> $outFinalPath", 'Move cropped video to final location')) {
            Move-Item -LiteralPath $outCropPath -Destination $outFinalPath -Force
        }
    } else {
        $formattedArgs = $ffArgs | ForEach-Object { if ($_ -match '\s') { "`"$_`"" } else { $_ } }
        Write-Host "WhatIf: Would crop video with ffmpeg $($formattedArgs -join ' ')"
    }

    $outInfo = Get-VideoInfo -Path $outFinalPath
    $outRes = "{0}x{1}" -f $outInfo.Width, $outInfo.Height
    $outFpsText = if ($outInfo.Fps) { "{0:0.###}" -f $outInfo.Fps } else { 'unknown' }
    $outQuality = Format-Quality -BitRate $outInfo.BitRate
    $outAudioText = if ($outInfo.HasAudio) { 'yes' } else { 'no' }

    Write-Host "Output: Filename=$($outInfo.FileName) Resolution=$outRes FPS=$outFpsText Quality=$outQuality Audio=$outAudioText"

    $processedCount++
}

Write-Host "Processed (cropped) videos: $processedCount"