using System.Text.Json;

namespace CareFix.Core;

public sealed record QueryResult(IReadOnlyList<string> Columns, List<object?[]> Rows, bool Truncated, int DurationMs);
public sealed record StepChange(string Table, string PkColumn, string PkValue, string Column, string? ExpectedOld, string? NewValue);
public sealed record ValueRead(int Rows, string? Value);
public sealed record SchemaColumn(string SchemaName, string TableName, string ColumnName, string DataType, bool IsNullable, bool IsPk);
public sealed record SqlLimits(int MaxRowsPerSelect, int SelectTimeoutSeconds, int LockTimeoutMs);

/// <summary>An error whose message is safe to show to users. Status follows HTTP codes.</summary>
public sealed class OpsException(int status, string message) : Exception(message)
{
    public int Status { get; } = status;
}

/// <summary>Wire protocol between the CareFix server and the on-prem agent.</summary>
public static class AgentProtocol
{
    public const string HospitalHeader = "X-CareFix-Hospital";
    public const string KeyHeader = "X-CareFix-Agent-Key";

    public static readonly JsonSerializerOptions Json = new(JsonSerializerDefaults.Web);

    public static class Kinds
    {
        public const string Select = "select";
        public const string AnyRows = "anyRows";
        public const string GetValue = "getValue";
        public const string GetRow = "getRow";
        public const string ApplySteps = "applySteps";
        public const string ReadSchema = "readSchema";
        public const string Test = "test";
    }

    /// <summary>Converts JSON values that came over the wire back to plain CLR values (string, long, decimal, bool, null).</summary>
    public static object? ToPlain(JsonElement e) => e.ValueKind switch
    {
        JsonValueKind.Null or JsonValueKind.Undefined => null,
        JsonValueKind.String => e.GetString(),
        JsonValueKind.True => true,
        JsonValueKind.False => false,
        JsonValueKind.Number => e.TryGetInt64(out var l) ? l : e.TryGetDecimal(out var d) ? d : e.GetDouble(),
        _ => e.GetRawText(),
    };
}

public sealed record AgentPoll(string Version, string MachineName);
public sealed record AgentJob(long JobId, string Kind, JsonElement Payload);
public sealed record AgentResult(bool Ok, JsonElement? Result, int? ErrorStatus, string? Error);

public sealed record SelectPayload(string Sql);
public sealed record AnyRowsPayload(string Sql, string PkValue);
public sealed record ValuePayload(string Table, string PkColumn, string PkValue, string Column);
public sealed record RowPayload(string Table, string PkColumn, string PkValue);
public sealed record ApplyPayload(List<StepChange> Steps, string TicketRef);
public sealed record SelectResultDto(List<string> Columns, List<JsonElement[]> Rows, bool Truncated, int DurationMs);