[CmdletBinding()]
param(
    [string]$Source,
    [string]$Dest,
    [string]$SkillsDir,
    [string]$Agent = $(if ($env:HTSY_SKILL_AGENT) { $env:HTSY_SKILL_AGENT } else { "" }),
    [string]$Repo = $(if ($env:HTSY_SKILL_REPO_URL) { $env:HTSY_SKILL_REPO_URL } else { "https://git.ikuban.com/server/htsy-skill.git" })
)

$ErrorActionPreference = "Stop"

function Resolve-Dest {
    param(
        [string]$ExactDest,
        [string]$ParentSkillsDir,
        [string]$TargetAgent
    )

    if ($ExactDest) {
        return $ExactDest
    }

    if ($env:HTSY_SKILL_DEST) {
        return $env:HTSY_SKILL_DEST
    }

    if (-not $ParentSkillsDir -and $env:AGENT_SKILLS_DIR) {
        $ParentSkillsDir = $env:AGENT_SKILLS_DIR
    }

    if ($ParentSkillsDir) {
        return Join-Path $ParentSkillsDir "htsy"
    }

    switch ($TargetAgent) {
        "claude" {
            $claudeHome = $env:CLAUDE_HOME
            if (-not $claudeHome) {
                $claudeHome = Join-Path $HOME ".claude"
            }
            return Join-Path (Join-Path $claudeHome "skills") "htsy"
        }
        "claude-user" {
            $claudeHome = $env:CLAUDE_HOME
            if (-not $claudeHome) {
                $claudeHome = Join-Path $HOME ".claude"
            }
            return Join-Path (Join-Path $claudeHome "skills") "htsy"
        }
        "claude-project" {
            return Join-Path (Join-Path (Join-Path (Get-Location).Path ".claude") "skills") "htsy"
        }
        "codex" {
            $codexHome = $env:CODEX_HOME
            if (-not $codexHome) {
                $codexHome = Join-Path $HOME ".codex"
            }
            return Join-Path (Join-Path $codexHome "skills") "htsy"
        }
        "" {
            throw "Specify -Agent claude|claude-project|codex, -SkillsDir, or -Dest."
        }
        default {
            throw "Unknown agent: $TargetAgent"
        }
    }
}

function Copy-Skill {
    param(
        [Parameter(Mandatory = $true)][string]$From,
        [Parameter(Mandatory = $true)][string]$To
    )

    if (-not (Test-Path (Join-Path $From "SKILL.md"))) {
        throw "Invalid source: $From does not contain SKILL.md"
    }

    $destParent = Split-Path -Parent $To
    if (-not (Test-Path $destParent)) {
        New-Item -ItemType Directory -Force $destParent | Out-Null
    }

    $tmpDest = Join-Path $destParent (".htsy-install-{0}" -f ([guid]::NewGuid().ToString("N")))
    New-Item -ItemType Directory -Force $tmpDest | Out-Null

    try {
        Get-ChildItem -LiteralPath $From -Force | Copy-Item -Destination $tmpDest -Recurse -Force

        if (Test-Path $To) {
            Remove-Item -Path $To -Recurse -Force
        }

        Move-Item -Path $tmpDest -Destination $To
    }
    catch {
        if (Test-Path $tmpDest) {
            Remove-Item -Path $tmpDest -Recurse -Force
        }
        throw
    }
}

$Dest = Resolve-Dest -ExactDest $Dest -ParentSkillsDir $SkillsDir -TargetAgent $Agent

$scriptDir = Split-Path -Parent $MyInvocation.MyCommand.Path
$repoRoot = (Resolve-Path (Join-Path $scriptDir "..")).Path
$tempRoot = $null

try {
    if (-not $Source) {
        $localSkill = Join-Path $repoRoot "htsy"
        if (Test-Path (Join-Path $localSkill "SKILL.md")) {
            $Source = $localSkill
        }
        else {
            if (-not (Get-Command git -ErrorAction SilentlyContinue)) {
                throw "git is required when the local htsy/ directory is unavailable."
            }

            $tempRoot = Join-Path ([System.IO.Path]::GetTempPath()) ("htsy-skill-{0}" -f ([guid]::NewGuid().ToString("N")))
            git clone --depth 1 $Repo $tempRoot
            $Source = Join-Path $tempRoot "htsy"
        }
    }

    Copy-Skill -From $Source -To $Dest

    Write-Host "Installed htsy skill to: $Dest"
    Write-Host "Verify: $(Join-Path $Dest 'SKILL.md')"
}
finally {
    if ($tempRoot -and (Test-Path $tempRoot)) {
        Remove-Item -Path $tempRoot -Recurse -Force
    }
}