require('dotenv').config();

const config = {
    bus: {
        url: process.env.BUS_URL,
        mpiUrl: process.env.MPI_URL || process.env.BUS_URL,
        documentRegistryUrl: process.env.DOCUMENT_REGISTRY_URL || process.env.BUS_URL,
        jwtSecret: process.env.BUS_JWT_SECRET,
        issuer: process.env.BUS_ISSUER,
        mpiScope: process.env.MPI_SCOPE,
        documentRegistryScope: process.env.DOCUMENT_REGISTRY_SCOPE,
    },
    fhir: {
        url: process.env.FHIR_URL,
    },
    logging: {
        enabled: true,
        level: 'debug',
        depthLimit: 5,
        edgeLimit: 100,
        msgPrefix: undefined,
        crlf: false,
        messageKey: 'msg',
        errorKey: 'err',
        nestedKey: null,
    },
    vhl: {
        // Path to an EC P-256 private key in PEM format for signing CWTs.
        // If omitted, an ephemeral key is generated at startup (lost on restart).
        privateKeyFile: process.env.VHL_PRIVATE_KEY_FILE,
        // URI identifying this gateway as the CWT issuer (iss claim).
        // Defaults to BUS_ISSUER so no extra variable is needed in most deployments.
        issuer: process.env.VHL_ISSUER || process.env.BUS_ISSUER,
        // Public base URL of this gateway, used to build manifest and document URLs.
        // Required when the VHL endpoints are used.
        baseUrl: process.env.VHL_BASE_URL,
        // VHL token and document TTL in seconds (default: 7 days).
        ttl: parseInt(process.env.VHL_TOKEN_TTL || '604800', 10),
    },
    baseURL: process.env.NODO_BASE_URL || 'http://localhost',
    debug: process.env.BUS_DEBUG === 'true',
};

const required = [
    ['BUS_URL', config.bus.url],
    ['BUS_JWT_SECRET', config.bus.jwtSecret],
    ['BUS_ISSUER', config.bus.issuer],
    ['MPI_SCOPE', config.bus.mpiScope],
    ['DOCUMENT_REGISTRY_SCOPE', config.bus.documentRegistryScope],
    ['FHIR_URL', config.fhir.url],
];

const missing = required.filter(([, val]) => !val).map(([key]) => key);
if (missing.length > 0) {
    throw new Error(`Missing required environment variables: ${missing.join(', ')}`);
}

module.exports = config;