param(
    [Parameter(Mandatory)][string]$FirstPath,
    [Parameter(Mandatory)][string]$SecondPath,
    [Parameter(Mandatory)][string]$OutputPath,
    [string]$CecilPath = (Join-Path $env:APPDATA 'XIVLauncher\addon\Hooks\dev\Mono.Cecil.dll')
)
$ErrorActionPreference = 'Stop'
Add-Type -Path $CecilPath
function Get-IcTypes($Types) {
    foreach ($icType in $Types) {
        $icType
        Get-IcTypes $icType.NestedTypes
    }
}
function Get-IcMetadata([string]$Path) {
    $icFile = Get-Item -LiteralPath $Path
    $icAsm = [Mono.Cecil.AssemblyDefinition]::ReadAssembly($icFile.FullName)
    try {
        $icAllTypes = @(Get-IcTypes $icAsm.MainModule.Types)
        $icNamedTypes = @($icAllTypes | Where-Object { $_.FullName -match '^[\x20-\x7E]+$' })
        $icShapes = [ordered]@{}
        foreach ($icType in $icNamedTypes) {
            $icShapes[$icType.FullName] = @(
                "TYPE $($icType.Attributes) SIZE $($icType.ClassSize) PACK $($icType.PackingSize) BASE $($icType.BaseType.FullName)"
                $icType.Interfaces | ForEach-Object { "INTERFACE $($_.InterfaceType.FullName)" }
                $icType.Fields | ForEach-Object { "FIELD $($_.FullName) OFFSET $($_.Offset) FLAGS $($_.Attributes)" }
                $icType.Methods | ForEach-Object { "METHOD $($_.FullName) FLAGS $($_.Attributes) IMPL $($_.ImplAttributes)" }
            ) | Sort-Object
        }
        [ordered]@{
            File=$icFile.Name
            Size=$icFile.Length
            SHA256=(Get-FileHash -LiteralPath $icFile.FullName).Hash
            Assembly=$icAsm.Name.FullName
            MVID=$icAsm.MainModule.Mvid.ToString()
            Architecture=$icAsm.MainModule.Architecture.ToString()
            Attributes=@($icAsm.CustomAttributes | Where-Object {
                $_.AttributeType.Name -match '^TargetFrameworkAttribute$|^Assembly(File|Informational)VersionAttribute$'
            } | ForEach-Object {
                [ordered]@{Type=$_.AttributeType.FullName; Values=@($_.ConstructorArguments | ForEach-Object { [string]$_.Value })}
            })
            References=@($icAsm.MainModule.AssemblyReferences | ForEach-Object { "$($_.Name) $($_.Version)" })
            Resources=@($icAsm.MainModule.Resources | ForEach-Object { "$($_.ResourceType) $($_.Name)" })
            TopLevelTypeCount=$icAsm.MainModule.Types.Count
            TotalTypeCount=$icAllTypes.Count
            AsciiNamedTypeCount=$icNamedTypes.Count
            TypeShapes=$icShapes
        }
    } finally { $icAsm.Dispose() }
}
$icFirst = Get-IcMetadata $FirstPath
$icSecond = Get-IcMetadata $SecondPath
$icOnlyFirst = @($icFirst.TypeShapes.Keys | Where-Object { !$icSecond.TypeShapes.Contains($_) })
$icOnlySecond = @($icSecond.TypeShapes.Keys | Where-Object { !$icFirst.TypeShapes.Contains($_) })
$icChanges = foreach ($icName in $icFirst.TypeShapes.Keys) {
    if (!$icSecond.TypeShapes.Contains($icName)) { continue }
    $icDiff = @(Compare-Object $icFirst.TypeShapes[$icName] $icSecond.TypeShapes[$icName])
    if ($icDiff.Count -gt 0) {
        [ordered]@{Type=$icName; Differences=@($icDiff | ForEach-Object {
            [ordered]@{OnlyIn=if ($_.SideIndicator -eq '=>') {'Second'} else {'First'}; Declaration=$_.InputObject}
        })}
    }
}
$icOutput = [ordered]@{
    First=$icFirst
    Second=$icSecond
    AsciiTypesOnlyInFirst=$icOnlyFirst
    AsciiTypesOnlyInSecond=$icOnlySecond
    CommonTypeMetadataChanges=@($icChanges)
    Limitation='Static declarations only; equal metadata does not establish equal method bodies or behavior. No target assembly was executed.'
}
$icOutput | ConvertTo-Json -Depth 12 | Set-Content -LiteralPath $OutputPath -Encoding utf8
"Saved comparison: $OutputPath"