param(
    [switch]$DryRun
)

$ErrorActionPreference = "Continue"

$script:RepoRoot = [System.IO.Path]::GetFullPath((Join-Path $PSScriptRoot ".."))
$script:LogPath = Join-Path $script:RepoRoot ".git/graphify-hook.log"

function Write-HookLog {
    param([string]$Message)

    $timestamp = Get-Date -Format "yyyy-MM-dd HH:mm:ss"
    $line = "[$timestamp] $Message"
    Write-Host $line
    try {
        Add-Content -Path $script:LogPath -Value $line -Encoding UTF8
    }
    catch {
        Write-Host "[graphify hook] Unable to write log: $($_.Exception.Message)"
    }
}

function Test-GraphifyPython {
    param([string]$PythonPath)

    if ([string]::IsNullOrWhiteSpace($PythonPath)) {
        return $false
    }

    try {
        & $PythonPath -c "import graphify" *> $null
        return ($LASTEXITCODE -eq 0)
    }
    catch {
        return $false
    }
}

function Get-GraphifyPython {
    $candidates = @()

    foreach ($relative in @("Unity/graphify-out/.graphify_python", "graphify-out/.graphify_python")) {
        $path = Join-Path $script:RepoRoot $relative
        if (Test-Path $path) {
            $value = (Get-Content -Raw -Path $path -Encoding UTF8).Trim()
            if ($value) {
                $candidates += $value
            }
        }
    }

    foreach ($command in @("python", "py")) {
        $cmd = Get-Command $command -ErrorAction SilentlyContinue
        if ($cmd) {
            $candidates += $cmd.Source
        }
    }

    foreach ($candidate in $candidates | Select-Object -Unique) {
        if (Test-GraphifyPython $candidate) {
            return $candidate
        }
    }

    return $null
}

function Get-ChangedFiles {
    $fromEnv = $env:GRAPHIFY_CHANGED
    if (-not [string]::IsNullOrWhiteSpace($fromEnv)) {
        return $fromEnv -split "`r?`n" | Where-Object { -not [string]::IsNullOrWhiteSpace($_) }
    }

    $git = Get-Command git -ErrorAction SilentlyContinue
    if (-not $git) {
        return @()
    }

    Push-Location $script:RepoRoot
    try {
        $files = & git diff --name-only HEAD~1 HEAD 2>$null
        if (-not $files) {
            $files = & git diff --name-only HEAD 2>$null
        }
        return @($files | Where-Object { -not [string]::IsNullOrWhiteSpace($_) })
    }
    finally {
        Pop-Location
    }
}

function Test-GitPathLike {
    param(
        [string]$Path,
        [string[]]$Patterns
    )

    foreach ($pattern in $Patterns) {
        if ($Path -like $pattern) {
            return $true
        }
    }
    return $false
}

function Get-MatchingGitPaths {
    param(
        [string[]]$Paths,
        [string[]]$Patterns
    )

    return @($Paths | Where-Object { Test-GitPathLike -Path $_ -Patterns $Patterns })
}

function Set-GraphifyNeedsUpdate {
    param(
        [string]$RelativePath,
        [string]$Reason
    )

    $target = Join-Path $script:RepoRoot $RelativePath
    $out = Join-Path $target "graphify-out"
    if (-not (Test-Path $out)) {
        return
    }

    $flag = Join-Path $out "needs_update"
    $timestamp = Get-Date -Format "yyyy-MM-dd HH:mm:ss"
    Add-Content -Path $flag -Value "[$timestamp] $Reason" -Encoding UTF8
    Write-HookLog "Marked $RelativePath graph for manual semantic update: $Reason"
}

function Invoke-GraphifyRebuild {
    param(
        [string]$Label,
        [string]$RelativePath,
        [string]$PythonPath
    )

    $target = Join-Path $script:RepoRoot $RelativePath
    $graphPath = Join-Path $target "graphify-out/graph.json"

    if (-not (Test-Path $graphPath)) {
        Write-HookLog "Skipping ${Label}: no graphify-out/graph.json found."
        return
    }

    if ($DryRun) {
        Write-HookLog "Dry run: would rebuild $Label graph at $target."
        return
    }

    Write-HookLog "Rebuilding $Label graph at $target."
    Push-Location $target
    try {
        & $PythonPath -c "from pathlib import Path; from graphify.watch import _rebuild_code; _rebuild_code(Path('.'))" *> $null
        if ($LASTEXITCODE -eq 0) {
            Write-HookLog "Rebuilt $Label graph."
        }
        else {
            Write-HookLog "Rebuild failed for $Label with exit code $LASTEXITCODE."
        }
    }
    catch {
        Write-HookLog "Rebuild failed for ${Label}: $($_.Exception.Message)"
    }
    finally {
        Pop-Location
    }
}

function Invoke-HookMain {
Set-Location $script:RepoRoot

$changedFiles = @(
    Get-ChangedFiles |
        ForEach-Object { $_ -replace '\\', '/' } |
        Where-Object {
            -not [string]::IsNullOrWhiteSpace($_) -and
            $_ -notlike "graphify-out/*" -and
            $_ -notlike "Unity/graphify-out/*"
        }
)
if ($changedFiles.Count -eq 0) {
    Write-HookLog "No changed files detected; nothing to rebuild."
    return 0
}

$codeExtensions = @(
    ".cs", ".asmdef", ".shader", ".hlsl", ".cginc",
    ".py", ".js", ".ts", ".ps1", ".json", ".toml", ".yaml", ".yml"
)

$changedCode = @(
    $changedFiles | Where-Object {
        $ext = [System.IO.Path]::GetExtension($_).ToLowerInvariant()
        $codeExtensions -contains $ext
    }
)

$rootCodePatterns = @(
    "Unity/Assets/Scripts/*",
    "Tools/*.ps1",
    "Tools/*.py",
    "Tools/*.js",
    "Tools/OSS/*",
    "Tools/Dashboard/*.py",
    "ExcelExport/*"
)

$unityCodePatterns = @(
    "Unity/Assets/Scripts/*"
)

$graphifyConfigPatterns = @(
    ".graphifyignore",
    ".gitignore",
    "AGENTS.md",
    "Unity/.graphifyignore",
    "Tools/GraphifyPostCommit.ps1",
    "Tools/InstallGraphifyHook.ps1"
)

$semanticDocPatterns = @(
    "MD/GameMDFramework/*.md",
    "MD/GameMDFramework/*/*.md"
)

$rootChangedCode = @(Get-MatchingGitPaths -Paths $changedCode -Patterns $rootCodePatterns)
$unityChangedCode = @(Get-MatchingGitPaths -Paths $changedCode -Patterns $unityCodePatterns)
$changedGraphifyConfig = @(Get-MatchingGitPaths -Paths $changedFiles -Patterns $graphifyConfigPatterns)
$changedSemanticDocs = @(Get-MatchingGitPaths -Paths $changedFiles -Patterns $semanticDocPatterns)

if ($changedSemanticDocs.Count -gt 0) {
    Set-GraphifyNeedsUpdate -RelativePath "." -Reason "Architecture docs changed; run graphify update manually for semantic edges."
}

$shouldRebuildRoot = ($rootChangedCode.Count -gt 0 -or $changedGraphifyConfig.Count -gt 0)
$shouldRebuildUnity = ($unityChangedCode.Count -gt 0 -or ($changedGraphifyConfig | Where-Object { $_ -eq "Unity/.graphifyignore" }).Count -gt 0)

if (-not $shouldRebuildRoot -and -not $shouldRebuildUnity) {
    Write-HookLog "$($changedFiles.Count) changed file(s), but none are in the narrowed graphify AST scopes."
    return 0
}

$python = Get-GraphifyPython
if (-not $python) {
    Write-HookLog "No Python interpreter with graphify installed was found."
    return 0
}

Write-HookLog "$($changedFiles.Count) changed file(s); root scope: $($rootChangedCode.Count), Unity scope: $($unityChangedCode.Count), graphify config: $($changedGraphifyConfig.Count). Using Python: $python"

if ($shouldRebuildRoot) {
    Invoke-GraphifyRebuild -Label "root" -RelativePath "." -PythonPath $python
}
else {
    Write-HookLog "Skipping root graph: no narrowed root-scope code/config changed."
}

if ($shouldRebuildUnity) {
    Invoke-GraphifyRebuild -Label "Unity" -RelativePath "Unity" -PythonPath $python
}
else {
    Write-HookLog "Skipping Unity graph: no narrowed Unity-scope code/config changed."
}

return 0
}

$mutexName = "Local\TH1-GraphifyPostCommit"
$mutex = $null
$hasLock = $false

try {
    $mutex = [System.Threading.Mutex]::new($false, $mutexName)
    $hasLock = $mutex.WaitOne(0)
    if (-not $hasLock) {
        Write-HookLog "Another graphify rebuild is already running; skipping this post-commit run."
        exit 0
    }

    $exitCode = Invoke-HookMain
    exit $exitCode
}
catch {
    Write-HookLog "Graphify hook failed: $($_.Exception.Message)"
    exit 1
}
finally {
    if ($hasLock -and $mutex) {
        try {
            $mutex.ReleaseMutex() | Out-Null
        }
        catch {
        }
    }

    if ($mutex) {
        $mutex.Dispose()
    }
}