#Requires -Version 5.1
<#
.SYNOPSIS
    Installs OpenCode (open-source AI coding agent) on Windows.

.DESCRIPTION
    Auto-detects the latest release from https://github.com/anomalyco/opencode/releases,
    downloads the zip file matching your Windows architecture, extracts opencode.exe
    to $env:USERPROFILE\.local\bin, and adds the directory to your User PATH.

    Supported architectures:
      - x64  (AMD64 / Intel 64-bit)
      - ARM64 (Qualcomm Snapdragon, ARM 64-bit)

.PARAMETER InstallDir
    Directory to install opencode.exe. Default: $env:USERPROFILE\.local\bin

.PARAMETER AddToPath
    Whether to permanently add InstallDir to user PATH. Default: $true

.EXAMPLE
    .\install-opencode.ps1

    # One-liner install from remote (works on Windows 10+):
    powershell -ExecutionPolicy Bypass -c "[Net.ServicePointManager]::SecurityProtocol=[Net.SecurityProtocolType]::Tls12; $t=\"$env:TEMP\install-opencode.ps1\"; iwr -useb 'https://gl.isitsoft.kr/publicproj/install-sh/-/raw/main/install-opencode.ps1' -OutFile $t; & $t"

.NOTES
    If execution policy error occurs:
      Set-ExecutionPolicy -ExecutionPolicy RemoteSigned -Scope CurrentUser
#>

[CmdletBinding()]
param(
    [string] $InstallDir = "$env:USERPROFILE\.local\bin",
    [bool]   $AddToPath  = $true
)

Set-StrictMode -Version Latest
$ErrorActionPreference = 'Stop'

# Enforce TLS 1.2+ for HTTPS downloads (required on Windows 10 / PowerShell 5.1)
[Net.ServicePointManager]::SecurityProtocol = [Net.SecurityProtocolType]::Tls12

# ────────────────────────────────────────────
# Constants
# ────────────────────────────────────────────
$REPO = "anomalyco/opencode"
$API_URL = "https://api.github.com/repos/$REPO/releases/latest"
$FALLBACK_TAG = "v1.18.35"

# ────────────────────────────────────────────
# Utility functions (English only to prevent Windows console encoding issues)
# ────────────────────────────────────────────
function Info    { Write-Host "[INFO]  $args" -ForegroundColor Cyan }
function Warn    { Write-Host "[WARN]  $args" -ForegroundColor Yellow }
function Success { Write-Host "[OK]    $args" -ForegroundColor Green }
function ErrExit { Write-Host "[ERROR] $args" -ForegroundColor Red; exit 1 }

# ────────────────────────────────────────────
# Platform detection
# ────────────────────────────────────────────
function Get-Platform {
    $arch = $env:PROCESSOR_ARCHITEW6432
    if (-not $arch) { $arch = $env:PROCESSOR_ARCHITECTURE }

    switch -Regex ($arch) {
        '^(AMD64|x64)$' { return 'windows-x64' }
        '^(ARM64)$'     { return 'windows-arm64' }
        default {
            ErrExit "Unsupported CPU architecture: '$arch'. Supported: x64, ARM64."
        }
    }
}

# ────────────────────────────────────────────
# Fetch latest release tag and asset URL
# ────────────────────────────────────────────
function Get-ReleaseInfo {
    param([string]$Platform)

    Info "Fetching latest OpenCode release from GitHub..."
    $tag = $FALLBACK_TAG
    $assetUrl = $null
    $targetPattern = "opencode-${Platform}.zip"

    try {
        $headers = @{ 'User-Agent' = 'install-opencode-ps1' }
        $release = Invoke-RestMethod -Uri $API_URL -Headers $headers -TimeoutSec 10 -UseBasicParsing
        if ($release -and $release.tag_name) {
            $tag = $release.tag_name
            $asset = $release.assets | Where-Object { $_.name -like "*${Platform}.zip" } | Select-Object -First 1
            if ($asset -and $asset.browser_download_url) {
                $assetUrl = $asset.browser_download_url
            }
        }
    } catch {
        Warn "GitHub API lookup failed: $_"
        Warn "Using fallback release tag: $FALLBACK_TAG"
    }

    if (-not $assetUrl) {
        $cleanTag = $tag.TrimStart('v')
        $assetUrl = "https://github.com/$REPO/releases/download/$tag/opencode-$Platform.zip"
    }

    return @{
        Tag = $tag
        Url = $assetUrl
    }
}

# ────────────────────────────────────────────
# Download and install binary
# ────────────────────────────────────────────
function Install-OpenCode {
    param(
        [string]$Url,
        [string]$TargetDir
    )

    if (-not (Test-Path $TargetDir)) {
        New-Item -ItemType Directory -Path $TargetDir -Force | Out-Null
    }

    $tmpDir = Join-Path $env:TEMP "opencode_install_$(Get-Random)"
    New-Item -ItemType Directory -Path $tmpDir -Force | Out-Null
    $zipPath = Join-Path $tmpDir "opencode.zip"

    try {
        Info "Downloading OpenCode archive..."
        Info "URL: $Url"
        $ProgressPreference = 'SilentlyContinue'
        Invoke-WebRequest -Uri $Url -OutFile $zipPath -UseBasicParsing
        $ProgressPreference = 'Continue'

        if (-not (Test-Path $zipPath)) {
            ErrExit "Failed to download OpenCode archive from $Url"
        }

        Info "Extracting opencode.exe to $TargetDir..."
        Add-Type -AssemblyName System.IO.Compression.FileSystem
        $archive = [System.IO.Compression.ZipFile]::OpenRead($zipPath)
        $extracted = $false

        foreach ($entry in $archive.Entries) {
            if ($entry.Name -eq "opencode.exe") {
                $destFile = Join-Path $TargetDir "opencode.exe"
                [System.IO.Compression.ZipFileExtensions]::ExtractToFile($entry, $destFile, $true)
                $extracted = $true
                break
            }
        }
        $archive.Dispose()

        if (-not $extracted) {
            ErrExit "opencode.exe was not found inside the downloaded archive."
        }

        Success "opencode.exe installed successfully into $TargetDir"
    } finally {
        if (Test-Path $tmpDir) {
            Remove-Item -Path $tmpDir -Recurse -Force -ErrorAction SilentlyContinue
        }
    }
}

# ────────────────────────────────────────────
# Register PATH environment variable
# ────────────────────────────────────────────
function Update-PathEnvironment {
    param([string]$Dir)

    $normalizedDir = $Dir.TrimEnd('\')

    # Current session PATH
    if ($env:Path -notlike "*$normalizedDir*") {
        $env:Path = "$normalizedDir;$env:Path"
        Info "Added $normalizedDir to current session PATH."
    }

    # Permanent User PATH in Windows Registry
    $userPath = [System.Environment]::GetEnvironmentVariable('Path', 'User')
    if (-not $userPath) { $userPath = '' }
    $pathParts = $userPath -split ';' | Where-Object { $_ -ne '' }

    $alreadyInPath = $false
    foreach ($p in $pathParts) {
        if ($p.Trim().TrimEnd('\') -eq $normalizedDir) {
            $alreadyInPath = $true
            break
        }
    }

    if (-not $alreadyInPath) {
        $newUserPath = if ($userPath) { "$normalizedDir;$userPath" } else { $normalizedDir }
        [System.Environment]::SetEnvironmentVariable('Path', $newUserPath, 'User')
        Success "Added $normalizedDir to User PATH permanently."
        Warn "Please open a new terminal window for PATH changes to take full effect."
    } else {
        Info "$normalizedDir is already present in User PATH."
    }
}

# ────────────────────────────────────────────
# Main Entry Point
# ────────────────────────────────────────────
function Main {
    Info "===== OpenCode install script (Windows PowerShell) ====="
    Info "Target install directory: $InstallDir"

    $platform = Get-Platform
    Info "Detected platform: $platform"

    $releaseInfo = Get-ReleaseInfo -Platform $platform
    Info "Release version: $($releaseInfo.Tag)"

    Install-OpenCode -Url $releaseInfo.Url -TargetDir $InstallDir

    if ($AddToPath) {
        Update-PathEnvironment -Dir $InstallDir
    } else {
        Warn "Skipping PATH environment update as requested (-AddToPath `$false)."
    }

    Success "OpenCode installation completed successfully!"
    Info ""
    Info "How to run:"
    Info "  opencode             - Launch interactive TUI coding session"
    Info "  opencode auth login  - Configure AI model provider accounts"
    Info "  opencode --help      - Show help and available commands"
    Info ""
}

Main