using System;

namespace IdleSpectator;

/// <summary>Builds target-aware happiness clauses from the authored catalog.</summary>
public static class ActivityHappinessProse
{
    public static string TaskKey(string effectId)
    {
        return "happiness:" + (effectId ?? "").Trim();
    }

    public static bool TryParseTaskKey(string key, out string effectId)
    {
        effectId = "";
        if (string.IsNullOrEmpty(key))
        {
            return false;
        }

        const string prefix = "happiness:";
        if (key.Length <= prefix.Length
            || !key.StartsWith(prefix, StringComparison.OrdinalIgnoreCase))
        {
            return false;
        }

        effectId = key.Substring(prefix.Length).Trim();
        return !string.IsNullOrEmpty(effectId);
    }

    public static string Clause(
        HappinessCatalogEntry entry,
        string relatedName,
        out bool usedRelated,
        out bool authored)
    {
        usedRelated = false;
        authored = entry != null && !entry.IsFallback && EventCatalog.Happiness.HasAuthored(entry.Id);
        if (entry == null)
        {
            return "feels a change in happiness";
        }

        bool hasRelated = !string.IsNullOrEmpty(relatedName);
        string[] variants = hasRelated && entry.VariantsWithRelated != null && entry.VariantsWithRelated.Length > 0
            ? entry.VariantsWithRelated
            : entry.VariantsWithoutRelated;
        if (variants == null || variants.Length == 0)
        {
            variants = entry.VariantsWithoutRelated;
        }

        if (variants == null || variants.Length == 0)
        {
            return "feels a change in happiness";
        }

        int idx = Math.Abs((entry.Id + (relatedName ?? "")).GetHashCode()) % variants.Length;
        string template = variants[idx] ?? "";
        usedRelated = hasRelated && template.IndexOf("{related}", StringComparison.Ordinal) >= 0;
        return ApplyTemplate(template, subjectName: "", relatedName: relatedName ?? "");
    }

    public static string ApplyTemplate(string template, string subjectName, string relatedName)
    {
        if (string.IsNullOrEmpty(template))
        {
            return "";
        }

        string result = template;
        if (!string.IsNullOrEmpty(subjectName))
        {
            result = result.Replace("{subject}", subjectName);
        }

        if (!string.IsNullOrEmpty(relatedName))
        {
            result = result.Replace("{related}", relatedName);
        }
        else
        {
            // Strip unresolved related placeholders defensively.
            result = result.Replace("{related}", "someone");
        }

        return result;
    }

    public static string FallbackClause(string effectId)
    {
        string id = string.IsNullOrEmpty(effectId) ? "unknown" : effectId.Replace('_', ' ');
        return "feels " + id;
    }
}