using System.Security.Cryptography;
using System.Text;

namespace WxAgent.Core;

public enum KeyBindingConfidence
{
    PageHmacVerified
}

public sealed record DatabaseKeyEvidence(
    string RelativePath,
    string Salt,
    string EncKey,
    int SourceProcessId,
    DateTimeOffset VerifiedAt,
    KeyBindingConfidence Confidence);

public sealed record AccountKeySet(
    string AccountRootFingerprint,
    string AccountRootPath,
    string? WechatVersion,
    DateTimeOffset LastSeenAt,
    IReadOnlyList<DatabaseKeyEvidence> Databases);

public static class AccountKeySetMerge
{
    public static IReadOnlyList<AccountKeySet> Merge(
        IReadOnlyList<AccountKeySet> existing,
        IReadOnlyList<AccountKeySet> incoming)
    {
        var accounts = existing.ToDictionary(account => account.AccountRootFingerprint, StringComparer.OrdinalIgnoreCase);
        foreach (var current in incoming)
        {
            if (!accounts.TryGetValue(current.AccountRootFingerprint, out var previous))
            {
                accounts[current.AccountRootFingerprint] = current;
                continue;
            }

            var databases = previous.Databases.ToDictionary(database => database.RelativePath, StringComparer.OrdinalIgnoreCase);
            foreach (var database in current.Databases)
            {
                databases[database.RelativePath] = database;
            }

            accounts[current.AccountRootFingerprint] = current with
            {
                WechatVersion = current.WechatVersion ?? previous.WechatVersion,
                Databases = databases.Values.OrderBy(database => database.RelativePath, StringComparer.OrdinalIgnoreCase).ToArray()
            };
        }

        return accounts.Values.OrderBy(account => account.AccountRootFingerprint, StringComparer.OrdinalIgnoreCase).ToArray();
    }
}

public static class AccountRootFingerprint
{
    public static string Create(string accountRootPath)
    {
        ArgumentException.ThrowIfNullOrWhiteSpace(accountRootPath);
        var normalized = accountRootPath.Replace('/', '\\').TrimEnd('\\').ToUpperInvariant();
        return Convert.ToHexString(SHA256.HashData(Encoding.UTF8.GetBytes(normalized))).ToLowerInvariant();
    }
}