export type CoordinateSpace = "pixels" | "normalized_1000";

export function readCoordinateSpace(value = "pixels"): CoordinateSpace {
    if (value !== "pixels" && value !== "normalized_1000") {
        throw new Error("DESKTOP_COORDINATE_SPACE must be pixels or normalized_1000.");
    }
    return value;
}

export interface Config {
    llamaCppOrigin: string;
    modelId: string;
    databasePath: string;
    coordinateSpace: CoordinateSpace;
}

export function readConfig(environment: NodeJS.ProcessEnv = process.env): Config {
    const origin = environment.LLAMA_CPP_ORIGIN?.trim();
    const modelId = environment.LLAMA_CPP_MODEL_ID?.trim();
    if (!origin || !modelId) {
        throw new Error("Set LLAMA_CPP_ORIGIN and LLAMA_CPP_MODEL_ID in .env (see .env.example).");
    }
    const url = new URL(origin);
    if (!["http:", "https:"].includes(url.protocol) || url.username || url.password
        || url.pathname !== "/" || url.search || url.hash) {
        throw new Error("LLAMA_CPP_ORIGIN must be an HTTP(S) origin without credentials, path, query, or fragment.");
    }
    return {
        coordinateSpace: readCoordinateSpace(environment.DESKTOP_COORDINATE_SPACE),
        llamaCppOrigin: url.origin,
        modelId,
        databasePath: environment.DATABASE_PATH?.trim() || "./data/token.sqlite",
    };
}