#pragma once

/**
 * @file ConfigManager.h
 * @brief Persistent storage of application configuration using LittleFS + JSON.
 *
 * Responsibilities:
 *  - Load/save AppConfig (pages, tiles, WiFi credentials) to /config.json
 *  - Provide typed accessors for individual fields
 *  - Expose helpers for the web UI to read/write pages as JSON fragments
 */

#include "Config.h"
#include <ArduinoJson.h>

class ConfigManager {
public:
    /**
     * @brief Initialise LittleFS and load configuration from disk.
     *        Must be called before any other method.
     * @return true on success, false if LittleFS mount failed.
     */
    bool begin();

    /** @brief Access the live configuration object (read-only). */
    const AppConfig& config() const { return _cfg; }

    /** @brief Write a complete AppConfig and persist it immediately. */
    bool save(const AppConfig& cfg);

    /** @brief Persist the current in-memory config to disk. */
    bool persist();

    // ── Page helpers ──────────────────────────────────────────────────────────

    /** @brief Return the currently active page index. */
    uint8_t activePage() const { return _cfg.activePage; }

    /** @brief Switch active page; persists. */
    bool setActivePage(uint8_t index);

    /** @brief Advance to the next page (wraps around). */
    void nextPage();

    /** @brief Go back to the previous page (wraps around). */
    void prevPage();

    /** @brief Update a single tile in a given page; persists. */
    bool setTile(uint8_t page, uint8_t tile, DataField field, const char* label = nullptr);

    // ── JSON serialisation for the web UI ─────────────────────────────────────

    /**
     * @brief Serialise the full configuration to a JSON string.
     * @param[out] out   Destination String.
     */
    void toJson(String& out) const;

    /**
     * @brief Parse a JSON string produced by the web UI and merge it into
     *        the current config. Persists on success.
     * @return true if parsing and saving succeeded.
     */
    bool fromJson(const String& json);

    // ── Factory reset ─────────────────────────────────────────────────────────
    void resetToDefaults();

private:
    static constexpr const char* CONFIG_PATH = "/config.json";

    AppConfig _cfg;

    bool _load();
    bool _write();
    void _applyDefaults();
};

// Singleton accessor
extern ConfigManager configManager;