fengling-activity/src/Fengling.Activity.Domain/Strategies/Actions/LotteryAction.cs

namespace Fengling.Activity.Domain.Strategies.Actions;

using Fengling.Activity.Domain.ValueObjects;

public class LotteryAction : IActionStrategy
{
    public string StrategyType => "Lottery";

    public Task<ActionResult> ExecuteAsync(CampaignContext context, ActionConfig config, CancellationToken cancellationToken = default)
    {
        var lotteryPoolId = config.GetParameter<string>("LotteryPoolId");

        var random = new Random();
        var prizes = context.AdditionalData.TryGetValue("LotteryPrizes", out var prizesObj)
            ? prizesObj is List<Dictionary<string, object>> list ? list : null
            : null;

        Dictionary<string, object>? selectedPrize = null;

        if (prizes != null && prizes.Count > 0)
        {
            var totalWeight = prizes.Sum(p => p.TryGetValue("Weight", out var w) && w is int weight ? weight : 1);
            var randomValue = random.Next(totalWeight);
            var currentWeight = 0;

            foreach (var prize in prizes)
            {
                var weight = prize.TryGetValue("Weight", out var w) && w is int i ? i : 1;
                currentWeight += weight;
                if (randomValue < currentWeight)
                {
                    selectedPrize = prize;
                    break;
                }
            }
        }

        var rewards = new Dictionary<string, object?>
        {
            { "LotteryPoolId", lotteryPoolId ?? "" },
            { "CampaignId", context.CampaignId.ToString() },
            { "GrantedAt", DateTime.UtcNow }
        };

        if (selectedPrize != null)
        {
            rewards["Prize"] = selectedPrize;
            var name = selectedPrize.TryGetValue("Name", out var n) ? n?.ToString() : null;
            rewards["Message"] = $"Congratulations! You won: {name ?? "a prize"}";
        }
        else
        {
            rewards["Message"] = "Better luck next time!";
        }

        return Task.FromResult(ActionResult.Success(rewards));
    }
}