using System;
using System.Collections.Generic;
using static PKHeX.Core.EncounterServerDateCheck;

namespace PKHeX.Core;

/// <summary>
/// Provides indication that the encounter may or may not have a specific date range to consider.
/// </summary>
public interface IEncounterServerDate
{
    /// <summary>
    /// If true, the date range it may be acquired at is restricted to a specific date range.
    /// </summary>
    bool IsDateRestricted { get; }
}

/// <summary>
/// Enumeration indicating if a date range check is satisfied.
/// </summary>
public enum EncounterServerDateCheck
{
    /// <summary> No need to consider date range. </summary>
    None,
    /// <summary> Date does fall within the range it was available. </summary>
    Valid,
    /// <summary> Date does NOT fall within the range it was available. </summary>
    Invalid,
}

/// <summary>
/// Logic to check if a date obtained is within the date of availability.
/// </summary>
public static class EncounterServerDate
{
    private static bool IsValidDate(DateTime obtained, DateTime start) => obtained >= start && obtained <= DateTime.UtcNow;
    private static bool IsValidDate(DateTime obtained, DateTime start, DateTime end) => obtained >= start && obtained <= end;

    private static bool IsValidDate(DateTime obtained, (DateTime Start, DateTime? End) value)
    {
        var (start, end) = value;
        if (end is not { } x)
            return IsValidDate(obtained, start);
        return IsValidDate(obtained, start, x);
    }

    private static EncounterServerDateCheck Result(bool result) => result ? Valid : Invalid;

    public static EncounterServerDateCheck IsValidDate(this IEncounterServerDate enc, DateTime obtained) => enc switch
    {
        WC8 wc8 => Result(IsValidDateWC8(wc8.CardID, obtained)),
        WA8 wa8 => Result(IsValidDateWA8(wa8.CardID, obtained)),
        WB8 wb8 => Result(IsValidDateWB8(wb8.CardID, obtained)),
        _ => throw new ArgumentOutOfRangeException(nameof(enc)),
    };

    public static bool IsValidDateWC8(int cardID, DateTime obtained) => WC8Gifts.TryGetValue(cardID, out var time) && IsValidDate(obtained, time);
    public static bool IsValidDateWA8(int cardID, DateTime obtained) => WA8Gifts.TryGetValue(cardID, out var time) && IsValidDate(obtained, time);
    public static bool IsValidDateWB8(int cardID, DateTime obtained) => WB8Gifts.TryGetValue(cardID, out var time) && IsValidDate(obtained, time);

    /// <summary>
    /// Minimum date the gift can be received.
    /// </summary>
    public static readonly Dictionary<int, DateTime> WC8Gifts = new()
    {
        {9000, new DateTime(2020, 02, 12)}, // Bulbasaur
        {9001, new DateTime(2020, 02, 12)}, // Charmander
        {9002, new DateTime(2020, 02, 12)}, // Squirtle
        {9003, new DateTime(2020, 02, 12)}, // Pikachu
        {9004, new DateTime(2020, 02, 15)}, // Original Color Magearna
        {9005, new DateTime(2020, 02, 12)}, // Eevee
        {9006, new DateTime(2020, 02, 12)}, // Rotom
        {9007, new DateTime(2020, 02, 12)}, // Pichu
        {9008, new DateTime(2020, 06, 02)}, // Hidden Ability Grookey
        {9009, new DateTime(2020, 06, 02)}, // Hidden Ability Scorbunny
        {9010, new DateTime(2020, 06, 02)}, // Hidden Ability Sobble
        {9011, new DateTime(2020, 06, 30)}, // Shiny Zeraora
        {9012, new DateTime(2020, 11, 10)}, // Gigantamax Melmetal
        {9013, new DateTime(2021, 06, 17)}, // Gigantamax Bulbasaur
        {9014, new DateTime(2021, 06, 17)}, // Gigantamax Squirtle
    };

    private static readonly DateTime? Never = null;

    /// <summary>
    /// Minimum date the gift can be received.
    /// </summary>
    public static readonly Dictionary<int, (DateTime Start, DateTime? End)> WA8Gifts = new()
    {
        {0138, (new(2022, 01, 27), new(2023, 02, 01))}, // Poké Center Happiny
        {0301, (new(2022, 02, 04), new(2023, 03, 01))}, // プロポチャ Piplup
        {0801, (new(2022, 02, 25), new(2022, 06, 01))}, // Teresa Roca Hisuian Growlithe
        {1201, (new(2022, 05, 31), new(2022, 08, 01))}, // 전이마을 Regigigas
        {1202, (new(2022, 05, 31), new(2022, 08, 01))}, // 빛나's Piplup

        {9018, (new(2022, 05, 18), Never)}, // Hidden Ability Rowlet
        {9019, (new(2022, 05, 18), Never)}, // Hidden Ability Cyndaquil
        {9020, (new(2022, 05, 18), Never)}, // Hidden Ability Oshawott
    };

    /// <summary>
    /// Minimum date the gift can be received.
    /// </summary>
    public static readonly Dictionary<int, (DateTime Start, DateTime? End)> WB8Gifts = new()
    {
        {9015, (new(2022, 05, 18), Never)}, // Hidden Ability Turtwig
        {9016, (new(2022, 05, 18), Never)}, // Hidden Ability Chimchar
        {9017, (new(2022, 05, 18), Never)}, // Hidden Ability Piplup
    };
}