const fs = require("fs/promises");
const path = require("path");
const { loadEnv } = require("./env");

let cached = null;

function parseNumber(value) {
    const parsed = Number(value);
    return Number.isFinite(parsed) ? parsed : null;
}

function applyEnvOverrides(config = {}) {
    const merged = { ...config };

    merged.rebrickable = { ...(config.rebrickable || {}) };
    if (process.env.REBRICKABLE_API_KEY) {
        merged.rebrickable.apiKey = process.env.REBRICKABLE_API_KEY;
    }

    const weather = config.weather || {};
    const providers = weather.providers || {};

    merged.weather = { ...weather, providers: { ...providers } };
    merged.weather.providers.influxdb = { ...(providers.influxdb || {}) };
    merged.weather.providers.openMeteo = { ...(providers.openMeteo || {}) };

    if (process.env.WEATHER_INFLUXDB_URL) {
        merged.weather.providers.influxdb.url = process.env.WEATHER_INFLUXDB_URL;
    }
    if (process.env.WEATHER_INFLUXDB_TOKEN) {
        merged.weather.providers.influxdb.token = process.env.WEATHER_INFLUXDB_TOKEN;
    }

    const envLatitude = parseNumber(process.env.WEATHER_OPEN_METEO_LATITUDE);
    if (envLatitude !== null) {
        merged.weather.providers.openMeteo.latitude = envLatitude;
    }

    const envLongitude = parseNumber(process.env.WEATHER_OPEN_METEO_LONGITUDE);
    if (envLongitude !== null) {
        merged.weather.providers.openMeteo.longitude = envLongitude;
    }

    merged.goaccess = { ...(config.goaccess || {}) };
    if (process.env.GOACCESS_URL) {
        merged.goaccess.url = process.env.GOACCESS_URL;
    }

    return merged;
}

async function loadToolsConfig(configPath = "tools/config/config.json") {
    const resolved = path.resolve(configPath);
    if (cached && cached.path === resolved) {
        return cached.data;
    }

    loadEnv();
    const raw = await fs.readFile(resolved, "utf8");
    const data = applyEnvOverrides(JSON.parse(raw));
    cached = { path: resolved, data };
    return data;
}

module.exports = {
    applyEnvOverrides,
    loadToolsConfig,
};