import type { PwshNativeConfig } from "./config.ts";

export const UTF8_PREFIX = [
	"$__pi_utf8 = [System.Text.UTF8Encoding]::new($false)",
	"[Console]::InputEncoding = $__pi_utf8",
	"[Console]::OutputEncoding = $__pi_utf8",
	"$OutputEncoding = $__pi_utf8",
	"$PSStyle.OutputRendering = 'PlainText'",
	"$global:LASTEXITCODE = $null",
].join("; ") + "; ";

/**
 * Report the final command's status. A successful final command wins over a
 * stale LASTEXITCODE; a failed final native command retains its real code;
 * other PowerShell failures map to 1.
 *
 * The leading newline detaches the epilogue from a trailing line comment. The
 * leading semicolon also prevents a trailing backtick from joining the
 * epilogue to the user's final command.
 */
export const EXIT_EPILOGUE =
	"\n; $__pi_ok = $?; if ($__pi_ok) { exit 0 } elseif ($null -ne $global:LASTEXITCODE -and $global:LASTEXITCODE -ne 0) { exit $global:LASTEXITCODE } else { exit 1 }";

export function buildPowerShellSource(command: string, config: PwshNativeConfig): string {
	const strict = config.strictMode ? "$ErrorActionPreference = 'Stop'; " : "";
	return `${UTF8_PREFIX}${strict}${command}${EXIT_EPILOGUE}`;
}

export const SOURCE_BOOTSTRAP =
	"$__pi_source = [System.Text.Encoding]::UTF8.GetString([System.Convert]::FromBase64String([Console]::In.ReadToEnd())); & ([ScriptBlock]::Create($__pi_source))";

export function buildPowerShellArguments(config: PwshNativeConfig): string[] {
	const args = ["-NoLogo"];
	if (!config.loadProfile) args.push("-NoProfile");
	args.push("-NonInteractive");
	if (config.executionPolicy) args.push("-ExecutionPolicy", config.executionPolicy);
	// PowerShell decodes `-Command -` input with the console code page before a
	// UTF-8 prelude can run. Transporting UTF-8 source as base64 over stdin keeps
	// the bootstrap ASCII-only, preserves Unicode, and avoids command-line limits.
	args.push("-Command", SOURCE_BOOTSTRAP);
	return args;
}