using System.Data.Common;
using System.Data.OleDb;
using System.Runtime.Versioning;
using Campaign_Tracker.Server.LegacyData.Models;

namespace Campaign_Tracker.Server.LegacyData;

/// <summary>
/// Read-only OleDb implementation for legacy Access-derived data.
/// All SQL is parameterized and validated as SELECT-only before execution.
/// </summary>
[SupportedOSPlatform("windows")]
public sealed class OleDbLegacyDataAccess : ILegacyDataAccess
{
    private readonly string _connectionString;

    public OleDbLegacyDataAccess(string connectionString)
    {
        if (string.IsNullOrWhiteSpace(connectionString))
        {
            throw new ArgumentException("Legacy database connection string is required.", nameof(connectionString));
        }

        _connectionString = connectionString;
    }

    public async Task<LegacyJurisdiction?> GetJurisdictionAsync(
        string jCode,
        CancellationToken cancellationToken = default)
    {
        const string sql = """
            SELECT JCode, Name, MailingAddress, CityStateZip, Phone, Email
            FROM Jurisdiction
            WHERE JCode = ?
            """;

        var results = await QueryAsync(sql, [jCode], MapJurisdiction, cancellationToken);
        return results.FirstOrDefault();
    }

    public Task<IReadOnlyList<LegacyJurisdiction>> GetAllJurisdictionsAsync(
        CancellationToken cancellationToken = default)
    {
        const string sql = """
            SELECT JCode, Name, MailingAddress, CityStateZip, Phone, Email
            FROM Jurisdiction
            ORDER BY JCode
            """;

        return QueryAsync(sql, [], MapJurisdiction, cancellationToken);
    }

    public async Task<LegacyContact?> GetContactByIdAsync(
        int id,
        CancellationToken cancellationToken = default)
    {
        const string sql = """
            SELECT ID, JURISCODE, ContactName, Title, Email, Phone1, Phone2,
                   MailingAddress, MailingAddress2, MailingAddress3,
                   BusinessAddress, BusinessAddress2, BusinessAddress3,
                   TownshipName, TownshipNum
            FROM Contacts
            WHERE ID = ?
            """;

        var results = await QueryAsync(sql, [id], MapContact, cancellationToken);
        return results.FirstOrDefault();
    }

    public Task<IReadOnlyList<LegacyContact>> GetContactsByJurisdictionAsync(
        string jCode,
        CancellationToken cancellationToken = default)
    {
        const string sql = """
            SELECT ID, JURISCODE, ContactName, Title, Email, Phone1, Phone2,
                   MailingAddress, MailingAddress2, MailingAddress3,
                   BusinessAddress, BusinessAddress2, BusinessAddress3,
                   TownshipName, TownshipNum
            FROM Contacts
            WHERE JURISCODE = ?
            ORDER BY ID
            """;

        return QueryAsync(sql, [jCode], MapContact, cancellationToken);
    }

    public async Task<LegacyKit?> GetKitByIdAsync(
        int id,
        CancellationToken cancellationToken = default)
    {
        const string sql = """
            SELECT ID, Jcode, JobNumber, JobType, Status, Filename, Cass, InkJetJob,
                   CreatedOn, ExportedToSnailWorks, LabelsPrinted, OfficeCopiesAmount,
                   InboundStid, OutboundStid
            FROM Kit
            WHERE ID = ?
            """;

        var results = await QueryAsync(sql, [id], MapKit, cancellationToken);
        return results.FirstOrDefault();
    }

    public Task<IReadOnlyList<LegacyKit>> GetKitsByJurisdictionAsync(
        string jCode,
        CancellationToken cancellationToken = default)
    {
        const string sql = """
            SELECT ID, Jcode, JobNumber, JobType, Status, Filename, Cass, InkJetJob,
                   CreatedOn, ExportedToSnailWorks, LabelsPrinted, OfficeCopiesAmount,
                   InboundStid, OutboundStid
            FROM Kit
            WHERE Jcode = ?
            ORDER BY ID
            """;

        return QueryAsync(sql, [jCode], MapKit, cancellationToken);
    }

    public Task<IReadOnlyList<LegacyKitLabel>> GetKitLabelsByKitAsync(
        int kitId,
        CancellationToken cancellationToken = default)
    {
        const string sql = """
            SELECT ID, KitID, InBoundImb, InBoundImbDigits, InBoundSerial,
                   OutboundImb, OutboundImbDigits, OutboundSerial, SetNumber
            FROM KitLabels
            WHERE KitID = ?
            ORDER BY ID
            """;

        return QueryAsync(sql, [kitId], MapKitLabel, cancellationToken);
    }

    private async Task<IReadOnlyList<T>> QueryAsync<T>(
        string sql,
        IReadOnlyList<object> parameters,
        Func<DbDataReader, T> map,
        CancellationToken cancellationToken)
    {
        ReadOnlyCommandGuard.Validate(sql);

        try
        {
            await using var connection = new OleDbConnection(_connectionString);
            await connection.OpenAsync(cancellationToken);

            await using var command = connection.CreateCommand();
            command.CommandText = sql;
            foreach (var parameter in parameters)
            {
                command.Parameters.AddWithValue(string.Empty, parameter);
            }

            var results = new List<T>();
            await using var reader = await command.ExecuteReaderAsync(cancellationToken);
            while (await reader.ReadAsync(cancellationToken))
            {
                results.Add(map(reader));
            }

            return results;
        }
        catch (LegacyDataAccessException)
        {
            throw;
        }
        catch (Exception ex)
        {
            throw new LegacyDataAccessException("Legacy read operation failed.", ex);
        }
    }

    private static LegacyJurisdiction MapJurisdiction(DbDataReader reader) =>
        new(
            GetRequiredString(reader, "JCode"),
            GetString(reader, "Name"),
            GetString(reader, "MailingAddress"),
            GetString(reader, "CityStateZip"),
            GetString(reader, "Phone"),
            GetString(reader, "Email"));

    private static LegacyContact MapContact(DbDataReader reader) =>
        new(
            GetRequiredInt(reader, "ID"),
            GetRequiredString(reader, "JURISCODE"),
            GetString(reader, "ContactName"),
            GetString(reader, "Title"),
            GetString(reader, "Email"),
            GetString(reader, "Phone1"),
            GetString(reader, "Phone2"),
            GetString(reader, "MailingAddress"),
            GetString(reader, "MailingAddress2"),
            GetString(reader, "MailingAddress3"),
            GetString(reader, "BusinessAddress"),
            GetString(reader, "BusinessAddress2"),
            GetString(reader, "BusinessAddress3"),
            GetString(reader, "TownshipName"),
            GetString(reader, "TownshipNum"));

    private static LegacyKit MapKit(DbDataReader reader) =>
        new(
            GetRequiredInt(reader, "ID"),
            GetRequiredString(reader, "Jcode"),
            GetString(reader, "JobNumber"),
            GetString(reader, "JobType"),
            GetString(reader, "Status"),
            GetString(reader, "Filename"),
            GetBool(reader, "Cass"),
            GetBool(reader, "InkJetJob"),
            GetDateTime(reader, "CreatedOn"),
            GetDateTime(reader, "ExportedToSnailWorks"),
            GetDateTime(reader, "LabelsPrinted"),
            GetInt(reader, "OfficeCopiesAmount"),
            GetString(reader, "InboundStid"),
            GetString(reader, "OutboundStid"));

    private static LegacyKitLabel MapKitLabel(DbDataReader reader) =>
        new(
            GetRequiredInt(reader, "ID"),
            GetRequiredInt(reader, "KitID"),
            GetString(reader, "InBoundImb"),
            GetString(reader, "InBoundImbDigits"),
            GetString(reader, "InBoundSerial"),
            GetString(reader, "OutboundImb"),
            GetString(reader, "OutboundImbDigits"),
            GetString(reader, "OutboundSerial"),
            GetDouble(reader, "SetNumber"));

    private static string GetRequiredString(DbDataReader reader, string name)
    {
        var value = GetString(reader, name);
        return string.IsNullOrWhiteSpace(value)
            ? throw new LegacyDataAccessException($"Required legacy join key {name} was null or empty.")
            : value;
    }

    private static int GetRequiredInt(DbDataReader reader, string name) =>
        GetInt(reader, name)
        ?? throw new LegacyDataAccessException($"Required legacy join key {name} was null.");

    private static string? GetString(DbDataReader reader, string name)
    {
        var value = GetValue(reader, name);
        return value is null ? null : Convert.ToString(value);
    }

    private static int? GetInt(DbDataReader reader, string name)
    {
        var value = GetValue(reader, name);
        return value is null ? null : Convert.ToInt32(value);
    }

    private static double? GetDouble(DbDataReader reader, string name)
    {
        var value = GetValue(reader, name);
        return value is null ? null : Convert.ToDouble(value);
    }

    private static bool GetBool(DbDataReader reader, string name)
    {
        var value = GetValue(reader, name);
        return value is not null && Convert.ToBoolean(value);
    }

    private static DateTime? GetDateTime(DbDataReader reader, string name)
    {
        var value = GetValue(reader, name);
        return value is null ? null : Convert.ToDateTime(value);
    }

    private static object? GetValue(DbDataReader reader, string name)
    {
        var ordinal = reader.GetOrdinal(name);
        return reader.IsDBNull(ordinal) ? null : reader.GetValue(ordinal);
    }
}