<#
    MidgardPlus installer  -  Odin the Red
    https://midgardplus.odinthered.dev

    Installs BepInEx (Valheim pack), Jotunn and MidgardPlus into your Valheim folder.

    Run:
        irm https://midgardplus.odinthered.dev/install.ps1 | iex

    Nothing here runs as admin, nothing touches the registry, and nothing is uninstalled.
    Every file it writes lives inside your Valheim folder. To undo it, delete BepInEx,
    winhttp.dll, doorstop_config.ini and doorstop_libs from that folder.

    Prefer a window with proper controls for all 29 settings? There is a launcher:
        https://midgardplus.odinthered.dev/MidgardPlusLauncher.exe
#>

$ErrorActionPreference = 'Stop'
[Net.ServicePointManager]::SecurityProtocol = [Net.SecurityProtocolType]::Tls12

$BepInEx = 'https://thunderstore.io/package/download/denikson/BepInExPack_Valheim/5.4.2350/'
$Jotunn  = 'https://thunderstore.io/package/download/ValheimModding/Jotunn/2.30.0/'

# Resolved from Thunderstore at run time rather than pinned, so this script cannot go stale
# and start handing out an old build the way a hardcoded URL does.
$ModApi      = 'https://thunderstore.io/api/experimental/package/OdinTheRed/MidgardPlus/'
$ModFallback = 'https://thunderstore.io/package/download/OdinTheRed/MidgardPlus/'

function Say($msg, $colour = 'Gray') { Write-Host $msg -ForegroundColor $colour }

Say ''
Say '  MidgardPlus installer' Yellow
Say '  by Odin the Red' DarkYellow
Say ''

# ---------------------------------------------------------------- find Valheim
function Find-Valheim {
    # The usual place first.
    $guess = Join-Path ${env:ProgramFiles(x86)} 'Steam\steamapps\common\Valheim'
    if (Test-Path (Join-Path $guess 'valheim.exe')) { return $guess }

    # Otherwise ask Steam where its libraries are.
    $steam = $null
    foreach ($key in @('HKCU:\Software\Valve\Steam', 'HKLM:\SOFTWARE\WOW6432Node\Valve\Steam')) {
        try {
            $p = (Get-ItemProperty -Path $key -ErrorAction Stop).SteamPath
            if ($p) { $steam = $p.Replace('/', '\'); break }
        } catch { }
    }
    if (-not $steam) { return $null }

    $candidates = @(Join-Path $steam 'steamapps\common\Valheim')

    $vdf = Join-Path $steam 'steamapps\libraryfolders.vdf'
    if (Test-Path $vdf) {
        foreach ($line in Get-Content $vdf) {
            if ($line -match '"path"\s+"(.+?)"') {
                $lib = $matches[1].Replace('\\', '\')
                $candidates += (Join-Path $lib 'steamapps\common\Valheim')
            }
        }
    }

    foreach ($c in $candidates) {
        if (Test-Path (Join-Path $c 'valheim.exe')) { return $c }
    }
    return $null
}

$game = Find-Valheim

if (-not $game) {
    Say '  Could not find Valheim automatically.' Red
    Say ''
    $game = Read-Host '  Paste the folder containing valheim.exe'
    $game = $game.Trim('"').Trim()
    if (-not (Test-Path (Join-Path $game 'valheim.exe'))) {
        Say '  No valheim.exe in that folder. Nothing was changed.' Red
        return
    }
}

Say "  Valheim: $game" Green
Say ''

# ---------------------------------------------------------------- helpers
$work = Join-Path $env:TEMP ("midgardplus-" + [Guid]::NewGuid().ToString('N').Substring(0, 8))
New-Item -ItemType Directory -Path $work -Force | Out-Null

function Fetch($url, $name) {
    $out = Join-Path $work $name
    Say "  Downloading $name ..."
    Invoke-WebRequest -Uri $url -OutFile $out -UseBasicParsing
    return $out
}

# Extracts a zip, turning any "\" in an entry name into "/".
#
# A Thunderstore package built on Windows can store paths with backslashes, which the ZIP
# spec does not allow. Left alone that yields one file literally named "plugins\Mod.dll"
# instead of a plugins folder, and nothing ever loads.
function Unpack($zip, $name) {
    Add-Type -AssemblyName System.IO.Compression.FileSystem
    $dir = Join-Path $work ($name + '-x')
    New-Item -ItemType Directory -Path $dir -Force | Out-Null

    $archive = [IO.Compression.ZipFile]::OpenRead($zip)
    try {
        foreach ($entry in $archive.Entries) {
            $rel = $entry.FullName.Replace('\', '/').TrimStart('/')
            if (-not $rel) { continue }

            $full = Join-Path $dir ($rel -replace '/', '\')

            if ($rel.EndsWith('/') -or -not $entry.Name) {
                New-Item -ItemType Directory -Path $full -Force | Out-Null
                continue
            }

            $parent = Split-Path $full -Parent
            if ($parent) { New-Item -ItemType Directory -Path $parent -Force | Out-Null }
            [IO.Compression.ZipFileExtensions]::ExtractToFile($entry, $full, $true)
        }
    }
    finally {
        $archive.Dispose()
    }

    return $dir
}

try {
    # ------------------------------------------------------------ newest version
    $midUrl = $ModFallback
    $midVer = 'latest'
    try {
        $meta = Invoke-RestMethod -Uri $ModApi -UseBasicParsing
        if ($meta.latest.download_url) {
            $midUrl = $meta.latest.download_url
            $midVer = $meta.latest.version_number
        }
    } catch {
        Say '  Could not reach the Thunderstore API; taking the newest release instead.' DarkGray
    }

    $bepZip = Fetch $BepInEx 'BepInExPack_Valheim.zip'
    $jotZip = Fetch $Jotunn  'Jotunn.zip'
    $midZip = Fetch $midUrl  'MidgardPlus.zip'

    Say ''
    Say '  Installing ...'

    # --- BepInEx: the pack nests everything under BepInExPack_Valheim\
    $bepDir = Unpack $bepZip 'bep'
    $inner  = Join-Path $bepDir 'BepInExPack_Valheim'
    $src    = if (Test-Path $inner) { $inner } else { $bepDir }
    Copy-Item -Path (Join-Path $src '*') -Destination $game -Recurse -Force
    Say '    BepInEx' DarkGray

    $plugins = Join-Path $game 'BepInEx\plugins'
    New-Item -ItemType Directory -Path $plugins -Force | Out-Null

    # --- Jotunn: plugins\Jotunn.dll
    $jotDir = Unpack $jotZip 'jot'
    $jotDll = Get-ChildItem -Path $jotDir -Filter 'Jotunn.dll' -Recurse | Select-Object -First 1
    if (-not $jotDll) { throw 'Jotunn.dll was not in the download.' }
    Copy-Item $jotDll.FullName -Destination $plugins -Force
    Say '    Jotunn' DarkGray

    # --- MidgardPlus: its own folder, so uninstalling is one delete
    $midDir = Unpack $midZip 'mid'
    $midDll = Get-ChildItem -Path $midDir -Filter 'MidgardPlus.dll' -Recurse | Select-Object -First 1
    if (-not $midDll) { throw 'MidgardPlus.dll was not in the download.' }
    $target = Join-Path $plugins 'MidgardPlus'
    New-Item -ItemType Directory -Path $target -Force | Out-Null
    Copy-Item $midDll.FullName -Destination $target -Force
    Say "    MidgardPlus $midVer" DarkGray

    Say ''
    Say '  Done.' Green
    Say ''
    Say '  Start Valheim once, then edit your settings here:' Gray
    Say "    $game\BepInEx\config\midgardplus.cfg" Yellow
    Say ''
    Say '  Or use the launcher, which gives every setting a proper control:' Gray
    Say '    https://midgardplus.odinthered.dev/MidgardPlusLauncher.exe' Yellow
    Say ''
    Say '  Everything starts at vanilla, so nothing changes until you turn it on.' DarkGray
    Say ''
}
catch {
    Say ''
    Say "  Install failed: $($_.Exception.Message)" Red
    Say '  Nothing was left half-written outside your Valheim folder.' DarkGray
    Say '  Manual download: https://midgardplus.odinthered.dev' Gray
    Say ''
}
finally {
    Remove-Item $work -Recurse -Force -ErrorAction SilentlyContinue
}