# tools-sync: mechanical sync of skills between Claude Code and Codex.
# Phase 1 — git sync of the primary checkout (~\.claude\skills): commit -> pull --rebase -> push.
# Phase 2 — junction reconciliation: every top-level skill dir in the primary gets a
#           directory junction of the same name in ~\.codex\skills, so both tools share
#           one physical copy and can never drift. Codex auto-registers any dir there
#           containing SKILL.md (new sessions only).
# Judgment calls (rebase conflicts, codex-local dirs worth keeping) are left to the caller.

param(
    [Parameter(Mandatory = $true)][string]$RepoUrl,
    [string]$ClaudeSkills = "$env:USERPROFILE\.claude\skills",
    [string]$CodexSkills = "$env:USERPROFILE\.codex\skills",
    [string]$Branch = "main",
    # A real (non-junction) dir in the codex side that shadows a primary skill blocks
    # linking; -Force deletes it and links (caller must have rescued unique content first).
    [switch]$Force,
    # Report what would happen without committing/pushing/linking.
    [switch]$DryRun
)

$ErrorActionPreference = "Stop"

function Invoke-Git {
    param([string]$Dir, [string[]]$GitArgs)
    # PS 5.1: git writes progress/warnings to stderr; 2>&1 wraps them in ErrorRecords
    # which terminate under EAP=Stop. Relax EAP locally and stringify every line.
    $prev = $ErrorActionPreference
    $ErrorActionPreference = "Continue"
    $out = & git -C $Dir @GitArgs 2>&1 | ForEach-Object { "$_" }
    $code = $LASTEXITCODE
    $ErrorActionPreference = $prev
    return @{ Code = $code; Out = (($out -join "`n")).Trim() }
}

function Fail([string]$Msg) { Write-Host "FAIL: $Msg"; exit 1 }

# ---------- Phase 1: primary checkout (~\.claude\skills) ----------
Write-Host "=== [1/2] primary git sync: $ClaudeSkills ==="
if (-not (Test-Path (Join-Path $ClaudeSkills ".git"))) {
    Fail "$ClaudeSkills is not a git repo. Clone $RepoUrl there first (new machine: git clone $RepoUrl `"$ClaudeSkills`")."
}

$st = Invoke-Git $ClaudeSkills @("status", "--porcelain")
if ($st.Out) {
    Write-Host "local changes:"; Write-Host $st.Out
    if ($DryRun) {
        Write-Host "(dry-run) would commit these changes"
    } else {
        Invoke-Git $ClaudeSkills @("add", "-A") | Out-Null
        $msg = "sync: $env:COMPUTERNAME $(Get-Date -Format yyyy-MM-dd)"
        $r = Invoke-Git $ClaudeSkills @("commit", "-m", $msg)
        if ($r.Code -ne 0) { Fail "commit failed:`n$($r.Out)" }
        Write-Host "committed: $msg"
    }
} else {
    Write-Host "working tree clean"
}

# The sync is only "done" when the remote branch actually points at our commit.
# ls-remote asks for refs only, so it keeps working even when the server's pack
# service is broken -- which is exactly the outage this gate exists to survive.
function Assert-RemoteInSync {
    param([string]$Dir, [string]$Branch)
    $local = Invoke-Git $Dir @("rev-parse", $Branch)
    if ($local.Code -ne 0) { Fail "cannot resolve local $Branch." }
    $ls = Invoke-Git $Dir @("ls-remote", "origin", "refs/heads/$Branch")
    if ($ls.Code -ne 0) {
        Write-Host $ls.Out
        Fail "ls-remote failed: cannot verify the push landed. Treat this run as NOT synced."
    }
    $remote = ($ls.Out -split "\s+")[0]
    if ($remote -ne $local.Out) {
        Write-Host "  local  $Branch = $($local.Out)"
        if (-not $remote) {
            # Empty ref: the counts below would silently be measured against HEAD.
            Fail "origin has no refs/heads/$Branch. Nothing on this machine is backed up by the server."
        }
        Write-Host "  remote $Branch = $remote"
        $ahead = Invoke-Git $Dir @("rev-list", "--count", "$remote..$($local.Out)")
        if ($ahead.Code -eq 0 -and [int]$ahead.Out -gt 0) {
            Write-Host "  $($ahead.Out) commit(s) STRANDED on this machine - they exist nowhere else."
        }
        $behind = Invoke-Git $Dir @("rev-list", "--count", "$($local.Out)..$remote")
        if ($behind.Code -eq 0 -and [int]$behind.Out -gt 0) {
            Write-Host "  $($behind.Out) commit(s) from other machines not merged here."
        }
        Fail "primary is NOT in sync with origin/$Branch. A server-side outage is a reason, never an outcome: do not report this run as synced."
    }
    Write-Host "verified: origin/$Branch = $remote (this machine's work is on the server)"
}

if ($DryRun) {
    # Read-only, but still worth running: silent drift is what this gate is for.
    Assert-RemoteInSync $ClaudeSkills $Branch
} else {
    $r = Invoke-Git $ClaudeSkills @("pull", "--rebase", "origin", $Branch)
    if ($r.Code -ne 0) {
        Write-Host $r.Out
        $stranded = Invoke-Git $ClaudeSkills @("rev-list", "--count", "origin/$Branch..$Branch")
        if ($stranded.Code -eq 0 -and [int]$stranded.Out -gt 0) {
            Write-Host "NOTE: $($stranded.Out) local commit(s) cannot reach the server until this is fixed."
        }
        Fail "pull --rebase failed on primary. Resolve conflicts (or 'git rebase --abort') then re-run. If the transport itself is broken (see skill Phase 1), fix the server -- do not leave commits stranded."
    }
    Write-Host $r.Out
    $r = Invoke-Git $ClaudeSkills @("push", "origin", $Branch)
    if ($r.Code -ne 0) { Write-Host $r.Out; Fail "push failed (auth? see skill Phase 1)." }
    Assert-RemoteInSync $ClaudeSkills $Branch
}

# ---------- Phase 2: junction reconciliation (~\.codex\skills) ----------
Write-Host "=== [2/2] codex junctions: $CodexSkills ==="
if (-not (Test-Path $CodexSkills)) { New-Item -ItemType Directory -Force $CodexSkills | Out-Null }

# Left over from the older mirror-checkout approach; junctions need no repo here.
if (Test-Path (Join-Path $CodexSkills ".git")) {
    Write-Host "removing stale .git from codex dir (junction model needs no second checkout)"
    if (-not $DryRun) { Remove-Item -Recurse -Force (Join-Path $CodexSkills ".git") }
}

$primarySkills = Get-ChildItem $ClaudeSkills -Directory | Where-Object { $_.Name -notlike ".*" }
$blocked = @()
foreach ($d in $primarySkills) {
    $link = Join-Path $CodexSkills $d.Name
    if (Test-Path $link) {
        $item = Get-Item $link
        if ($item.LinkType -eq "Junction") { continue }
        # A real dir shadows the primary skill; its content may be unique.
        if ($Force) {
            if ($DryRun) { Write-Host "(dry-run) would replace real dir with junction: $($d.Name)" ; continue }
            Remove-Item -Recurse -Force $link
            New-Item -ItemType Junction -Path $link -Target $d.FullName | Out-Null
            Write-Host "replaced real dir with junction: $($d.Name)"
        } else {
            $blocked += $d.Name
        }
    } else {
        if ($DryRun) { Write-Host "(dry-run) would link: $($d.Name)"; continue }
        New-Item -ItemType Junction -Path $link -Target $d.FullName | Out-Null
        Write-Host "linked: $($d.Name)"
    }
}

# Junctions whose primary target is gone (skill deleted/renamed upstream) confuse Codex.
foreach ($item in Get-ChildItem $CodexSkills -Directory | Where-Object { $_.LinkType -eq "Junction" }) {
    $target = ($item.Target | Select-Object -First 1)
    if ($target -and $target.StartsWith($ClaudeSkills) -and -not (Test-Path $target)) {
        if ($DryRun) { Write-Host "(dry-run) would remove stale junction: $($item.Name)"; continue }
        # A junction is just a link — removing it never touches target content.
        $item.Delete()
        Write-Host "removed stale junction: $($item.Name)"
    }
}

if ($blocked) {
    Write-Host "these codex dirs are REAL directories shadowing primary skills (not linked):"
    $blocked | ForEach-Object { Write-Host "  $_" }
    Fail "rescue any unique content into the primary checkout, then re-run with -Force."
}

# Registration sanity: every linked skill must expose a SKILL.md for Codex to register it.
$missing = $primarySkills | Where-Object { -not (Test-Path (Join-Path $CodexSkills "$($_.Name)\SKILL.md")) }
if ($missing) {
    Write-Host "WARNING: no SKILL.md visible through these links (Codex will ignore them):"
    $missing | ForEach-Object { Write-Host "  $($_.Name)" }
}

Write-Host "=== sync_repos done (Codex picks up changes on its next new session) ==="