namespace WxAgent.Core;

public sealed record UiAccountIdentity(string? WechatId, string? Nickname);
public sealed record DatabaseAccountIdentity(string AccountId, string? WechatId, string? Nickname);
public sealed record AccountMatch(string? AccountId, string Strategy, bool IsUnique)
{
    public bool IsMatched => AccountId is not null && IsUnique;
}

public static class AccountBindingMatcher
{
    public static AccountMatch Match(UiAccountIdentity ui, IReadOnlyList<DatabaseAccountIdentity> accounts)
    {
        ArgumentNullException.ThrowIfNull(ui);
        ArgumentNullException.ThrowIfNull(accounts);
        var wechatId = Normalize(ui.WechatId);
        if (wechatId is not null)
        {
            var matches = accounts.Where(a => string.Equals(Normalize(a.WechatId), wechatId, StringComparison.OrdinalIgnoreCase)).ToArray();
            if (matches.Length == 1) return new AccountMatch(matches[0].AccountId, "wechatId", true);
            if (matches.Length > 1) return new AccountMatch(null, "wechatId", false);
        }

        var nickname = Normalize(ui.Nickname);
        if (nickname is null) return new AccountMatch(null, "none", false);
        var nicknameMatches = accounts.Where(a => string.Equals(Normalize(a.Nickname), nickname, StringComparison.Ordinal)).ToArray();
        return nicknameMatches.Length == 1
            ? new AccountMatch(nicknameMatches[0].AccountId, "nickname", true)
            : new AccountMatch(null, nicknameMatches.Length == 0 ? "none" : "nickname", false);
    }

    private static string? Normalize(string? value) => string.IsNullOrWhiteSpace(value) ? null : value.Trim();
}