/**
 * One-time migration of provider credentials from Pi (~/.pi/agent/auth.json)
 * into SF's auth storage. Runs when SF has no LLM providers configured,
 * so users with an existing Pi install skip re-authentication.
 */

import { existsSync, readFileSync } from "node:fs";
import { homedir } from "node:os";
import { join } from "node:path";
import type {
	AuthCredential,
	AuthStorage,
} from "@singularity-forge/pi-coding-agent";

const PI_AUTH_PATH = join(homedir(), ".pi", "agent", "auth.json");
const PI_SETTINGS_PATH = join(homedir(), ".pi", "agent", "settings.json");

const LLM_PROVIDER_IDS = [
	"anthropic",
	"openai",
	"github-copilot",
	"openai-codex",
	"google-gemini-cli",
	"google",
	"groq",
	"xai",
	"openrouter",
	"mistral",
];

/**
 * Migrate provider credentials from Pi's auth.json into SF's AuthStorage.
 *
 * Only runs when SF has no LLM provider configured and Pi's auth.json exists.
 * Copies any credentials SF doesn't already have. Returns true if an LLM
 * provider was migrated (so onboarding can be skipped).
 */
export function migratePiCredentials(authStorage: AuthStorage): boolean {
	try {
		const existing = authStorage.list();
		const hasLlm = existing.some((id) => LLM_PROVIDER_IDS.includes(id));
		if (hasLlm) return false;

		if (!existsSync(PI_AUTH_PATH)) return false;

		const raw = readFileSync(PI_AUTH_PATH, "utf-8");
		const piData = JSON.parse(raw) as Record<string, AuthCredential>;

		let migratedLlm = false;
		for (const [providerId, credential] of Object.entries(piData)) {
			if (authStorage.has(providerId)) continue;
			authStorage.set(providerId, credential);
			const isLlm = LLM_PROVIDER_IDS.includes(providerId);
			if (isLlm) migratedLlm = true;
			process.stderr.write(
				`[forge] Migrated ${isLlm ? "LLM provider" : "credential"}: ${providerId} (from Pi)\n`,
			);
		}

		return migratedLlm;
	} catch {
		return false;
	}
}

export function getPiDefaultModelAndProvider(): {
	provider: string;
	model: string;
} | null {
	try {
		if (!existsSync(PI_SETTINGS_PATH)) return null;

		const raw = readFileSync(PI_SETTINGS_PATH, "utf-8");
		const data = JSON.parse(raw) as {
			defaultProvider?: unknown;
			defaultModel?: unknown;
		};
		if (
			typeof data.defaultProvider !== "string" ||
			typeof data.defaultModel !== "string"
		) {
			return null;
		}

		return {
			provider: data.defaultProvider,
			model: data.defaultModel,
		};
	} catch {
		return null;
	}
}