<#
.SYNOPSIS
  Downloads the AI workspace ZIP from Ka-Note and extracts it to work/.

.PARAMETER Prod
  Target production server instead of dev (localhost:3001).

.PARAMETER Token
  Bearer token for prod auth. Falls back to $env:KA_NOTE_TOKEN.

.PARAMETER Force
  Skip the work-directory cleanup confirmation prompt.

.EXAMPLE
  .\download.ps1
  .\download.ps1 -Prod -Token eyJ...
  .\download.ps1 -Force
#>
param(
  [switch]$Prod,
  [string]$Token,
  [switch]$Force
)

$ErrorActionPreference = 'Stop'

# --- Helpers -----------------------------------------------------------------

function Write-Header([string]$Text) {
  Write-Host ""
  Write-Host "  $Text" -ForegroundColor White
  Write-Host ("  " + ("-" * $Text.Length)) -ForegroundColor DarkGray
}

function Write-KV([string]$Key, [string]$Value, [string]$Color = "Gray") {
  Write-Host ("  {0,-14} " -f $Key) -NoNewline -ForegroundColor DarkGray
  Write-Host $Value -ForegroundColor $Color
}

function Write-Ok([string]$Msg)   { Write-Host "  [OK] $Msg" -ForegroundColor Green }
function Write-Err([string]$Msg)  { Write-Host "  [!!] $Msg" -ForegroundColor Red }
function Write-Hint([string]$Msg) { Write-Host "    -> $Msg" -ForegroundColor DarkCyan }

# --- Paths -------------------------------------------------------------------

$RepoRoot = Resolve-Path "$PSScriptRoot\..\.."
$WorkDir  = Join-Path $RepoRoot "work"
$ZipPath  = Join-Path $WorkDir "workspace.zip"

# --- Clean work directory ----------------------------------------------------

Write-Header "Ka-Note AI Download"

if (Test-Path $WorkDir) {
  $ExistingItems = @(Get-ChildItem -Path $WorkDir)
  if ($ExistingItems.Count -gt 0) {
    Write-KV "work dir"  $WorkDir
    Write-Host ""
    Write-Host "  The work directory contains $($ExistingItems.Count) item(s)." -ForegroundColor DarkGray
    Write-Host ""

    if (-not $Force) {
      $Answer = Read-Host "  Delete all contents and proceed? [y/N]"
      if ($Answer -notmatch '^[yY]$') {
        Write-Host "  Aborted." -ForegroundColor Yellow
        Write-Host ""
        exit 0
      }
    }

    Remove-Item -Path "$WorkDir\*" -Recurse -Force
    Write-Ok "Work directory cleared."
  }
} else {
  New-Item -ItemType Directory -Path $WorkDir | Out-Null
  Write-Ok "Created work directory: $WorkDir"
}

# --- Server ------------------------------------------------------------------

if ($Prod) {
  $BaseUrl     = "https://ka-note.azurewebsites.net"
  $BearerToken = if ($Token) { $Token } elseif ($env:KA_NOTE_TOKEN) { $env:KA_NOTE_TOKEN } else {
    Write-Host "  Acquiring token via MSAL..." -ForegroundColor DarkGray
    & "$PSScriptRoot\get-token.ps1"
  }
  if (-not $BearerToken) {
    Write-Err "Failed to acquire a Bearer token."
    exit 1
  }
  $Headers = @{ Authorization = "Bearer $BearerToken" }
  $Env = "prod"
} else {
  $BaseUrl = "http://localhost:3001"
  $Headers = @{}
  $Env = "dev"
}

Write-KV "server"  $BaseUrl  $(if ($Prod) { "Yellow" } else { "Cyan" })
Write-KV "mode"    $Env
Write-KV "work"    $WorkDir
Write-Host ""
Write-Host "  Downloading workspace.zip..." -ForegroundColor DarkGray

# --- Download ----------------------------------------------------------------

try {
  Invoke-WebRequest -Uri "$BaseUrl/api/ai/download" `
    -Method GET -Headers $Headers -OutFile $ZipPath -UseBasicParsing
} catch {
  $Code = $_.Exception.Response.StatusCode.value__
  Write-Err "HTTP $Code - $($_.Exception.Message)"
  exit 1
}

$LockToken = $null
# Lock token also in ZIP manifest (read after extract)

# --- Extract -----------------------------------------------------------------

Write-Host "  Extracting..." -ForegroundColor DarkGray
Expand-Archive -Path $ZipPath -DestinationPath $WorkDir -Force
Remove-Item -Path $ZipPath -Force

# --- Stats -------------------------------------------------------------------

$ManifestPath = Join-Path $WorkDir "manifest.json"
$Manifest     = Get-Content $ManifestPath -Raw -Encoding UTF8 | ConvertFrom-Json
$LockToken    = $Manifest.lockToken

$HistoryCount = @(Get-ChildItem -Path (Join-Path $WorkDir "history") -Filter "*.md" -ErrorAction SilentlyContinue).Count
$ImageCount   = @(Get-ChildItem -Path (Join-Path $WorkDir "images") -ErrorAction SilentlyContinue).Count

$CtxJson  = Get-Content (Join-Path $WorkDir "contexts.json") -Raw -Encoding UTF8 | ConvertFrom-Json
$TopJson  = Get-Content (Join-Path $WorkDir "topics.json")   -Raw -Encoding UTF8 | ConvertFrom-Json
$RatJson  = Get-Content (Join-Path $WorkDir "ratings.json")  -Raw -Encoding UTF8 | ConvertFrom-Json

Write-Header "Result"
Write-KV "contexts" @($CtxJson).Count
Write-KV "topics"   @($TopJson).Count
Write-KV "history"  $HistoryCount
Write-KV "ratings"  @($RatJson).Count
Write-KV "images"   $ImageCount
Write-KV "lock"     $LockToken               "Yellow"
Write-KV "expires"  $Manifest.expiresAt

Write-Host ""
Write-Ok "Workspace extracted to work/. Lock acquired - sync is paused."
Write-Host ""
Write-Host "  Next steps:" -ForegroundColor DarkGray
Write-Hint "Edit work/history/*.md with your AI tool"
Write-Hint ".\upload.ps1$(if ($Prod) { ' -Prod' })    - upload changes + release lock"
Write-Hint ".\unlock.ps1$(if ($Prod) { ' -Prod' })    - discard changes, release lock only"
Write-Host ""