using System.Collections.Generic;
using System.Collections.ObjectModel;
using HC_APTBS.Models;

namespace HC_APTBS.Services
{
    /// <summary>
    /// Provides read/write access to persisted application configuration.
    /// Configuration files live under <c>%UserProfile%\.HC_APTBS\config\</c>.
    /// </summary>
    public interface IConfigurationService
    {
        // ── Settings ──────────────────────────────────────────────────────────────

        /// <summary>Application-wide settings (temperature limits, PID, refresh rates, etc.).</summary>
        AppSettings Settings { get; }

        /// <summary>Persists <see cref="Settings"/> to <c>config.xml</c>.</summary>
        void SaveSettings();

        // ── Bench configuration ───────────────────────────────────────────────────

        /// <summary>
        /// Current bench CAN parameter map and relay definitions.
        /// Loaded from <c>bench.xml</c> on first access.
        /// </summary>
        BenchConfiguration Bench { get; }

        /// <summary>Persists <see cref="Bench"/> to <c>bench.xml</c>.</summary>
        void SaveBench();

        // ── Pump database ─────────────────────────────────────────────────────────

        /// <summary>Returns all known pump IDs from the pump database.</summary>
        IReadOnlyList<string> GetPumpIds();

        /// <summary>
        /// Loads the full <see cref="PumpDefinition"/> for the pump with the given ID,
        /// including its CAN parameter map and test list.
        /// </summary>
        PumpDefinition? LoadPump(string pumpId);

        /// <summary>Persists a pump definition back to the database.</summary>
        void SavePump(PumpDefinition pump);

        // ── Clients ───────────────────────────────────────────────────────────────

        /// <summary>Sorted client name → contact info dictionary.</summary>
        SortedDictionary<string, string> Clients { get; }

        /// <summary>Persists the client list to <c>clients.xml</c>.</summary>
        void SaveClients();

        // ── Pump status definitions ───────────────────────────────────────────────

        /// <summary>
        /// Loads the <see cref="PumpStatusDefinition"/> for the given status ID.
        /// Definitions are cached after first load.  Returns null if the ID is not found.
        /// </summary>
        PumpStatusDefinition? LoadPumpStatus(int statusId);

        // ── Alarms ────────────────────────────────────────────────────────────────

        /// <summary>Persists alarm definitions to <c>alarms.xml</c>.</summary>
        void SaveAlarms();

        // ── Sensors ───────────────────────────────────────────────────────────────

        /// <summary>Saves updated sensor calibration data to <c>sensors.xml</c>.</summary>
        void SaveSensors();

        // ── Users ─────────────────────────────────────────────────────────────────

        /// <summary>Validates a username/password pair against stored credentials.</summary>
        bool ValidateUser(string username, string password);

        /// <summary>Returns all stored usernames (passwords are never exposed).</summary>
        IReadOnlyList<string> GetUsers();

        /// <summary>Replaces all stored user credentials and persists them.</summary>
        void UpdateUsers(Dictionary<string, string> users);

        /// <summary>
        /// Adds a new user with the given plaintext password.
        /// Returns false if the username already exists, if either field is empty/whitespace,
        /// or if the username contains the reserved separator characters <c>':'</c> or <c>','</c>.
        /// Hashes of existing users are preserved.
        /// </summary>
        bool AddUser(string username, string password);

        /// <summary>
        /// Removes the user with the given username.
        /// Returns false if the user does not exist or if this would remove the last remaining user.
        /// Hashes of other users are preserved.
        /// </summary>
        bool RemoveUser(string username);

        /// <summary>
        /// Replaces the stored password for an existing user.
        /// Returns false if the user does not exist or the password is empty.
        /// Hashes of other users are preserved.
        /// </summary>
        bool ChangeUserPassword(string username, string newPassword);
    }
}