using NeonSprawl.Server.Game.Items;
using NeonSprawl.Server.Game.Mastery;
using NeonSprawl.Server.Game.PositionState;
using NeonSprawl.Server.Game.Rewards;
using NeonSprawl.Server.Game.Skills;

namespace NeonSprawl.Server.Game.Quests;

/// <summary>Maps <c>GET /game/players/{{id}}/quest-progress</c> (NEO-119).</summary>
public static class QuestProgressApi
{
    public const string StatusNotStarted = "not_started";
    public const string StatusActive = "active";
    public const string StatusCompleted = "completed";

    public static WebApplication MapQuestProgressApi(this WebApplication app)
    {
        app.MapGet(
            "/game/players/{id}/quest-progress",
            (string id, IPositionStateStore positions, IQuestDefinitionRegistry questRegistry,
                IPlayerQuestStateStore progressStore, IPlayerInventoryStore inventoryStore,
                IItemDefinitionRegistry itemRegistry, ISkillDefinitionRegistry skillRegistry,
                IPlayerSkillProgressionStore skillProgressionStore, ISkillLevelCurve levelCurve,
                PerkUnlockEngine perkUnlockEngine, IPlayerPerkStateStore perkStore,
                IRewardDeliveryStore deliveryStore, TimeProvider timeProvider, ILogger<Program>? logger) =>
            {
                var trimmedId = id.Trim();
                if (trimmedId.Length == 0 || !positions.TryGetPosition(trimmedId, out _))
                {
                    return Results.NotFound();
                }

                QuestObjectiveWiring.TryRefreshInventoryProgressForPlayer(
                    trimmedId,
                    questRegistry,
                    progressStore,
                    inventoryStore,
                    itemRegistry,
                    skillRegistry,
                    skillProgressionStore,
                    levelCurve,
                    perkUnlockEngine,
                    perkStore,
                    deliveryStore,
                    timeProvider,
                    logger);

                return Results.Json(BuildSnapshot(trimmedId, questRegistry, progressStore, deliveryStore));
            });

        return app;
    }

    internal static QuestProgressListResponse BuildSnapshot(
        string playerId,
        IQuestDefinitionRegistry questRegistry,
        IPlayerQuestStateStore progressStore,
        IRewardDeliveryStore deliveryStore)
    {
        var defs = questRegistry.GetDefinitionsInIdOrder();
        var rows = new List<QuestProgressRowJson>(defs.Count);
        foreach (var def in defs)
        {
            rows.Add(MapQuestProgressRow(playerId, def.Id, progressStore, deliveryStore));
        }

        return new QuestProgressListResponse
        {
            PlayerId = playerId,
            Quests = rows,
            SchemaVersion = QuestProgressListResponse.CurrentSchemaVersion,
        };
    }

    internal static QuestProgressRowJson MapQuestProgressRow(
        string playerId,
        string questId,
        IPlayerQuestStateStore progressStore,
        IRewardDeliveryStore deliveryStore)
    {
        if (!progressStore.TryGetProgress(playerId, questId, out var snapshot))
        {
            return NotStartedRow(questId);
        }

        return MapQuestProgressRow(playerId, snapshot, deliveryStore);
    }

    internal static QuestProgressRowJson MapQuestProgressRow(
        string playerId,
        QuestStepState snapshot,
        IRewardDeliveryStore deliveryStore)
    {
        var counters = new Dictionary<string, int>(snapshot.ObjectiveCounters, StringComparer.Ordinal);
        return snapshot.Status switch
        {
            QuestProgressStatus.Active => new QuestProgressRowJson
            {
                QuestId = snapshot.QuestId,
                Status = StatusActive,
                CurrentStepIndex = snapshot.CurrentStepIndex,
                ObjectiveCounters = counters,
            },
            QuestProgressStatus.Completed => new QuestProgressRowJson
            {
                QuestId = snapshot.QuestId,
                Status = StatusCompleted,
                CurrentStepIndex = snapshot.CurrentStepIndex,
                ObjectiveCounters = counters,
                CompletedAt = snapshot.CompletedAt,
                CompletionRewardSummary = MapCompletionRewardSummary(playerId, snapshot.QuestId, deliveryStore),
            },
            _ => throw new InvalidOperationException($"Unknown quest progress status '{snapshot.Status}'."),
        };
    }

    private static QuestCompletionRewardSummaryJson? MapCompletionRewardSummary(
        string playerId,
        string questId,
        IRewardDeliveryStore deliveryStore)
    {
        if (!deliveryStore.TryGet(playerId, questId, out var deliveryEvent))
        {
            return null;
        }

        return new QuestCompletionRewardSummaryJson
        {
            ItemGrants = MapItemGrants(deliveryEvent.GrantedItems),
            SkillXpGrants = MapSkillXpGrants(deliveryEvent.GrantedSkillXp),
        };
    }

    /// <summary>Preserves commit-time grant order from <see cref="RewardDeliveryEvent.GrantedItems"/>.</summary>
    private static List<QuestItemGrantJson> MapItemGrants(IReadOnlyList<RewardItemGrantApplied> grants)
    {
        var summary = new List<QuestItemGrantJson>(grants.Count);
        foreach (var grant in grants)
        {
            summary.Add(
                new QuestItemGrantJson
                {
                    ItemId = grant.ItemId,
                    Quantity = grant.Quantity,
                });
        }

        return summary;
    }

    /// <summary>Preserves commit-time grant order from <see cref="RewardDeliveryEvent.GrantedSkillXp"/>.</summary>
    private static List<QuestSkillXpGrantJson> MapSkillXpGrants(IReadOnlyList<RewardSkillXpGrantApplied> grants)
    {
        var summary = new List<QuestSkillXpGrantJson>(grants.Count);
        foreach (var grant in grants)
        {
            summary.Add(
                new QuestSkillXpGrantJson
                {
                    SkillId = grant.SkillId,
                    Amount = grant.Amount,
                });
        }

        return summary;
    }

    private static QuestProgressRowJson NotStartedRow(string questId) =>
        new()
        {
            QuestId = questId,
            Status = StatusNotStarted,
            CurrentStepIndex = 0,
            ObjectiveCounters = new Dictionary<string, int>(StringComparer.Ordinal),
        };
}