import type { EnglishTutorSettings } from "./settings.ts";
import type { ExtensionContext } from "@earendil-works/pi-coding-agent";
import type { Model } from "@earendil-works/pi-ai";

export interface ModelAuth {
	apiKey: string;
	headers?: Record<string, string>;
	env?: Record<string, string>;
}

export type ResolveModelResult = { ok: true; model: Model<any>; auth: ModelAuth } | { ok: false; error: string };

/** Resolves the configured correction model and its credentials, or a single human-readable failure reason. */
export async function resolveCorrectionModel(
	ctx: ExtensionContext,
	settings: EnglishTutorSettings,
): Promise<ResolveModelResult> {
	const model = ctx.modelRegistry.find(settings.correctionProvider, settings.correctionModel);
	if (!model) {
		return { ok: false, error: `Correction model not found: ${settings.correctionProvider}/${settings.correctionModel}` };
	}

	const auth = await ctx.modelRegistry.getApiKeyAndHeaders(model);
	if (!auth.ok) return { ok: false, error: auth.error };
	if (!auth.apiKey) return { ok: false, error: `No API key configured for ${settings.correctionProvider}` };

	return { ok: true, model, auth: { apiKey: auth.apiKey, headers: auth.headers, env: auth.env } };
}