using Dapper;
using JdeScoping.DataAccess.Interfaces;
using JdeScoping.Domain.Models;
using Microsoft.Extensions.Logging;

namespace JdeScoping.DataAccess.Services;

/// <summary>
/// Service implementation for managing manual data sync requests.
/// </summary>
public sealed class ManualSyncRequestService : IManualSyncRequestService
{
    private readonly IDbConnectionFactory _connectionFactory;
    private readonly ILogger<ManualSyncRequestService> _logger;

    /// <summary>
    /// Initializes a new instance of the <see cref="ManualSyncRequestService"/> class.
    /// </summary>
    /// <param name="connectionFactory">The database connection factory.</param>
    /// <param name="logger">The logger instance.</param>
    public ManualSyncRequestService(
        IDbConnectionFactory connectionFactory,
        ILogger<ManualSyncRequestService> logger)
    {
        _connectionFactory = connectionFactory ?? throw new ArgumentNullException(nameof(connectionFactory));
        _logger = logger ?? throw new ArgumentNullException(nameof(logger));
    }

    /// <inheritdoc/>
    public async Task<IReadOnlyList<ManualSyncRequest>> GetRequestsAsync(
        bool pendingOnly = false,
        CancellationToken ct = default)
    {
        _logger.LogDebug("Getting manual sync requests (pendingOnly: {PendingOnly})", pendingOnly);

        const string sqlAll = """
            SELECT ID, PipelineName, SyncType, RequestDT, RequestedBy,
                   CompletedDT, CancelDT, CancelledBy, RowVersion
            FROM dbo.ManualSyncRequest
            ORDER BY RequestDT DESC
            """;

        const string sqlPending = """
            SELECT ID, PipelineName, SyncType, RequestDT, RequestedBy,
                   CompletedDT, CancelDT, CancelledBy, RowVersion
            FROM dbo.ManualSyncRequest
            WHERE CompletedDT IS NULL AND CancelDT IS NULL
            ORDER BY RequestDT ASC
            """;

        await using var connection = await _connectionFactory.CreateLotFinderConnectionAsync(ct);
        var results = await connection.QueryAsync<ManualSyncRequest>(
            pendingOnly ? sqlPending : sqlAll);

        var list = results.ToList();
        _logger.LogDebug("Retrieved {Count} manual sync requests", list.Count);
        return list;
    }

    /// <inheritdoc/>
    public async Task<ManualSyncRequest?> GetNextPendingRequestAsync(CancellationToken ct = default)
    {
        _logger.LogDebug("Getting next pending manual sync request");

        const string sql = """
            SELECT TOP 1 ID, PipelineName, SyncType, RequestDT, RequestedBy,
                         CompletedDT, CancelDT, CancelledBy, RowVersion
            FROM dbo.ManualSyncRequest
            WHERE CompletedDT IS NULL AND CancelDT IS NULL
            ORDER BY RequestDT ASC
            """;

        await using var connection = await _connectionFactory.CreateLotFinderConnectionAsync(ct);
        var result = await connection.QueryFirstOrDefaultAsync<ManualSyncRequest>(sql);

        if (result != null)
        {
            _logger.LogDebug("Found pending request ID {Id} for pipeline {Pipeline}",
                result.Id, result.PipelineName);
        }
        else
        {
            _logger.LogDebug("No pending manual sync requests found");
        }

        return result;
    }

    /// <inheritdoc/>
    public async Task<ManualSyncRequest> CreateRequestAsync(
        string pipelineName,
        string syncType,
        string requestedBy,
        CancellationToken ct = default)
    {
        _logger.LogInformation(
            "Creating manual sync request for pipeline {Pipeline}, type {SyncType}, by {User}",
            pipelineName, syncType, requestedBy);

        const string sql = """
            INSERT INTO dbo.ManualSyncRequest (PipelineName, SyncType, RequestedBy)
            OUTPUT INSERTED.ID, INSERTED.PipelineName, INSERTED.SyncType,
                   INSERTED.RequestDT, INSERTED.RequestedBy,
                   INSERTED.CompletedDT, INSERTED.CancelDT, INSERTED.CancelledBy,
                   INSERTED.RowVersion
            VALUES (@PipelineName, @SyncType, @RequestedBy)
            """;

        await using var connection = await _connectionFactory.CreateLotFinderConnectionAsync(ct);
        var result = await connection.QuerySingleAsync<ManualSyncRequest>(sql, new
        {
            PipelineName = pipelineName,
            SyncType = syncType,
            RequestedBy = requestedBy
        });

        _logger.LogInformation("Created manual sync request with ID {Id}", result.Id);
        return result;
    }

    /// <inheritdoc/>
    public async Task<bool> CancelRequestAsync(
        int id,
        string cancelledBy,
        byte[] rowVersion,
        CancellationToken ct = default)
    {
        _logger.LogInformation(
            "Cancelling manual sync request ID {Id} by {User}",
            id, cancelledBy);

        const string sql = """
            UPDATE dbo.ManualSyncRequest
            SET CancelDT = @CancelDT, CancelledBy = @CancelledBy
            WHERE ID = @Id AND RowVersion = @RowVersion
              AND CompletedDT IS NULL AND CancelDT IS NULL
            """;

        await using var connection = await _connectionFactory.CreateLotFinderConnectionAsync(ct);
        var affectedRows = await connection.ExecuteAsync(sql, new
        {
            Id = id,
            CancelDT = DateTime.UtcNow,
            CancelledBy = cancelledBy,
            RowVersion = rowVersion
        });

        var success = affectedRows > 0;

        if (success)
        {
            _logger.LogInformation("Successfully cancelled manual sync request ID {Id}", id);
        }
        else
        {
            _logger.LogWarning(
                "Failed to cancel manual sync request ID {Id} - already completed/cancelled or version mismatch",
                id);
        }

        return success;
    }

    /// <inheritdoc/>
    public async Task<bool> CompleteRequestAsync(
        int id,
        byte[] rowVersion,
        CancellationToken ct = default)
    {
        _logger.LogInformation("Completing manual sync request ID {Id}", id);

        const string sql = """
            UPDATE dbo.ManualSyncRequest
            SET CompletedDT = @CompletedDT
            WHERE ID = @Id AND RowVersion = @RowVersion
              AND CompletedDT IS NULL AND CancelDT IS NULL
            """;

        await using var connection = await _connectionFactory.CreateLotFinderConnectionAsync(ct);
        var affectedRows = await connection.ExecuteAsync(sql, new
        {
            Id = id,
            CompletedDT = DateTime.UtcNow,
            RowVersion = rowVersion
        });

        var success = affectedRows > 0;

        if (success)
        {
            _logger.LogInformation("Successfully completed manual sync request ID {Id}", id);
        }
        else
        {
            _logger.LogWarning(
                "Failed to complete manual sync request ID {Id} - already completed/cancelled or version mismatch",
                id);
        }

        return success;
    }
}