using System;
using System.Collections.Generic;
using UnityEngine;

/// <summary>
/// Keep track of all users
/// </summary>
public static class UserList
{
    /// <summary>
    /// List of possible avatar sprites
    /// </summary>
    public static List<Sprite> AVATARS = new List<Sprite>();

    /// <summary>
    /// Create a new user and save (add to list)
    /// </summary>
    /// <param name="username">The username of the new user</param>
    /// <param name="avatar">Reference to the user avatar</param>
    /// <returns>A newly created user</returns>
    public static User AddUser(string username, Sprite avatar)
    {
        PersistentDataController pdc = PersistentDataController.GetInstance();
        PersistentDataController.SavedUserData data = new PersistentDataController.SavedUserData();
        data.username = username;
        data.playtime = 0.0;
        data.avatarIndex = AVATARS.IndexOf(avatar);

        pdc.AddUser(data);
        return new User(data);
    }

    /// <summary>
    /// Get a user by username
    /// </summary>
    /// <param name="username">The username of the user</param>
    /// <returns><c>User</c>-object if a user with such username was found, <c>null</c> otherwise</returns>
    public static User GetUserByUsername(string username)
    {
        foreach (User user in GetUsers())
            if (user.GetUsername() == username) return user;

        return null;
    }

    /// <summary>
    /// Get a user by index
    /// </summary>
    /// <param name="index">The index of the user</param>
    /// <returns>User object</returns>
    /// <exception cref="IndexOutOfRangeException"></exception>
    public static User GetUserByIndex(int index)
    {
        List<User> users = GetUsers();
        if (index < 0 || users.Count <= index)
            throw new IndexOutOfRangeException();

        return users[index];
    }

    /// <summary>
    /// Get a list of all users currently stored
    /// </summary>
    /// <returns>A list of all users</returns>
    public static List<User> GetUsers()
    {
        PersistentDataController pdc = PersistentDataController.GetInstance();
        return pdc.GetUsers().ConvertAll((d) => new User(d));
    }

    /// <summary>
    /// Get the current logged in user
    /// </summary>
    /// <returns>The current logged in user</returns>
    public static User GetCurrentUser()
    {
        List<User> users = GetUsers();
        if (users.Count == 0)
            return null;
        return users[PersistentDataController.GetInstance().GetCurrentUser()];
    }

    /// <summary>
    /// Get the index in the userlist of a user
    /// </summary>
    /// <returns></returns>
    public static int IndexOf(string username)
    {
        int idx = GetUsers().FindIndex((e) => e.GetUsername() == username);
        if (idx < 0)
            throw new KeyNotFoundException();
        return idx;
    }

    /// <summary>
    /// Change the current user
    /// </summary>
    /// <param name="index">Index of the user in the userlist</param>
    /// <exception cref="IndexOutOfRangeException"></exception>
    public static void ChangeCurrentUser(int index)
    {
        if (index < 0 || GetUsers().Count <= index)
            throw new IndexOutOfRangeException();

        PersistentDataController.GetInstance().SetCurrentUser(index, true);
    }


    /// <summary>
    /// Change the current user
    /// </summary>
    /// <param name="index">Username of the user</param>
    /// <exception cref="KeyNotFoundException"></exception>
    public static void ChangeCurrentUser(string username)
    {
        int index = GetUsers().FindIndex((e) => e.GetUsername() == username);
        try { ChangeCurrentUser(index); }
        catch (IndexOutOfRangeException) { throw new KeyNotFoundException(); }
    }

    /// <summary>
    /// I am inevitable, *snap*
    /// </summary>
    /// <param name="index">The index of the user in the userlist</param>
    /// <returns>true if the user was successful removed, false otherwise</returns>
    /// <exception cref="IndexOutOfRangeException"></exception>
    public static bool DeleteUser(int index)
    {
        List<User> users = GetUsers();
        if (index < 0 || users.Count <= index)
            throw new IndexOutOfRangeException();

        if (1 < users.Count)
        {
            PersistentDataController.GetInstance().DeleteUser(index);
            return true;
        }
        return false;
    }

    /// <summary>
    /// Delete a user from the userliset
    /// </summary>
    /// <param name="username">Username of the user</param>
    /// <returns>true if the user was successful removed, false otherwise</returns>
    /// <exception cref="KeyNotFoundException"></exception>
    public static bool DeleteUser(string username)
    {
        int index = GetUsers().FindIndex((e) => e.GetUsername() == username);

        try { return DeleteUser(index); }
        catch (IndexOutOfRangeException) { throw new KeyNotFoundException(); }
    }

    /// <summary>
    /// Save the current UserList
    /// </summary>
    public static void Save()
    {
        PersistentDataController.GetInstance().Save();
    }
}