using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace StellaOps.Provcache;

public sealed partial class DecisionDigestBuilder
{
    /// <summary>
    /// Sets the verdict hash directly.
    /// </summary>
    public DecisionDigestBuilder WithVerdictHash(string verdictHash)
    {
        _verdictHash = verdictHash ?? throw new ArgumentNullException(nameof(verdictHash));
        return this;
    }

    /// <summary>
    /// Computes verdict hash from sorted dispositions.
    /// Dispositions are sorted by key for deterministic hashing.
    /// </summary>
    /// <param name="dispositions">Dictionary of finding ID to disposition.</param>
    public DecisionDigestBuilder WithDispositions(IReadOnlyDictionary<string, string> dispositions)
    {
        ArgumentNullException.ThrowIfNull(dispositions);

        var sorted = dispositions
            .OrderBy(kvp => kvp.Key, StringComparer.Ordinal)
            .ToList();

        if (sorted.Count == 0)
        {
            _verdictHash = ComputeHash(Encoding.UTF8.GetBytes("empty-verdict"));
            return this;
        }

        var sb = new StringBuilder();
        foreach (var (key, value) in sorted)
        {
            if (sb.Length > 0) sb.Append('|');
            sb.Append(key);
            sb.Append('=');
            sb.Append(value);
        }

        _verdictHash = ComputeHash(Encoding.UTF8.GetBytes(sb.ToString()));
        return this;
    }
}