#Requires -Version 5.1
<#
.SYNOPSIS
    Create .venv inside the repo and install mcm-toolkit in editable mode.

.DESCRIPTION
    Uses --system-site-packages so the venv reuses the scientific stack already
    installed in Anaconda base. That makes the whole step OFFLINE: no package is
    downloaded, yet numpy / scipy / pandas / matplotlib / sklearn / statsmodels /
    networkx / sympy are all importable.

    The editable install uses --no-deps --no-build-isolation: dependencies are
    already provided by base, and pip must not go online for a build backend.

    NOTE: this file is intentionally pure ASCII and UTF-8 without BOM.
    Windows PowerShell 5.1 parses .ps1 as ANSI when there is no BOM, so non-ASCII
    characters (e.g. Chinese) turn into illegal bytes and cause syntax errors.

.PARAMETER Python
    Interpreter used to create the venv. Default: D:\anaconda\python.exe

.PARAMETER Recreate
    Delete and recreate .venv if it already exists.

.EXAMPLE
    .\scripts\setup-venv.ps1
#>
[CmdletBinding()]
param(
    [string]$Python = 'D:\anaconda\python.exe',
    [switch]$Recreate
)

$ErrorActionPreference = 'Stop'
$repoRoot = Split-Path -Parent $PSScriptRoot
$venvDir = Join-Path $repoRoot '.venv'

if (-not (Test-Path -LiteralPath $Python)) {
    $cmd = Get-Command python -ErrorAction SilentlyContinue
    if (-not $cmd) { throw "Python interpreter not found: $Python" }
    $Python = $cmd.Source
    Write-Host "Using python from PATH: $Python" -ForegroundColor Yellow
}

if (Test-Path -LiteralPath $venvDir) {
    if (-not $Recreate) {
        Write-Host '.venv already exists. Use -Recreate to rebuild.' -ForegroundColor Yellow
    } else {
        Write-Host 'Removing existing .venv ...'
        Remove-Item -LiteralPath $venvDir -Recurse -Force
    }
}

if (-not (Test-Path -LiteralPath $venvDir)) {
    Write-Host '[1/4] creating .venv (--system-site-packages, reuses Anaconda base) ...'
    & $Python -m venv --system-site-packages --prompt 'mcm-toolkit' $venvDir
    if ($LASTEXITCODE -ne 0) { throw 'venv creation failed' }
}

$venvPy = Join-Path $venvDir 'Scripts\python.exe'
$venvSitePackages = Join-Path $venvDir 'Lib\site-packages'

Write-Host '[2/4] linking base site-packages for static analyzers (.pth) ...'
# pyright / Pylance do NOT honour "include-system-site-packages" in pyvenv.cfg,
# but they DO read *.pth files found in site-packages. Without this file they see
# only .venv\Lib\site-packages (which holds just pip), so every "import numpy"
# in the editor is reported as unresolved even though the interpreter is right.
$baseSitePackages = (& $Python -c "import sysconfig; print(sysconfig.get_paths()['purelib'])").Trim()
if (-not (Test-Path -LiteralPath $baseSitePackages)) { throw "base site-packages not found: $baseSitePackages" }
Set-Content -LiteralPath (Join-Path $venvSitePackages '_mcm_base_site_packages.pth') -Value $baseSitePackages -Encoding ASCII
Write-Host "    -> $baseSitePackages"

Write-Host '[3/4] editable install of mcm-toolkit (--no-deps --no-build-isolation) ...'
& $venvPy -m pip install -e $repoRoot --no-deps --no-build-isolation --disable-pip-version-check
if ($LASTEXITCODE -ne 0) { throw 'pip install -e failed' }

Write-Host '[4/4] verifying ...'
& $venvPy -c "import mcm_toolkit, numpy, scipy, pandas, matplotlib; print('mcm_toolkit', mcm_toolkit.__version__); print('numpy', numpy.__version__)"

Write-Host ''
Write-Host 'Done. Activate with:' -ForegroundColor Green
Write-Host '    .\.venv\Scripts\Activate.ps1'