using DigitalData.TaskFlow.Application.Common.Interfaces;
using DigitalData.TaskFlow.Domain.Closing;
using DigitalData.TaskFlow.Domain.Workflows;
using DigitalData.TaskFlow.Infrastructure.Options;
using DigitalData.TaskFlow.Infrastructure.Persistence;
using DigitalData.TaskFlow.Infrastructure.Persistence.Models;
using Microsoft.Data.SqlClient;
using Microsoft.EntityFrameworkCore;
using Microsoft.Extensions.Options;
using System.Text.Json;

namespace DigitalData.TaskFlow.Infrastructure.Repositories;

/// <summary>
/// Workflow repository implementation for reading workflow listing data and applying close operations.
/// </summary>
public sealed class WorkflowRepository(TaskFlowDbContext dbContext, IOptions<DatabaseOptions> databaseOptions) : IWorkflowRepository
{
    /// <summary>
    /// Retrieves grouped workflow data for a user.
    /// </summary>
    /// <param name="wisagId">WISAG user identifier.</param>
    /// <param name="cancellationToken">Cancellation token.</param>
    /// <returns>Grouped workflow response.</returns>
    public async Task<WorkflowSourcesResponse> GetAsync(int wisagId, CancellationToken cancellationToken)
    {
        var objectType = string.IsNullOrWhiteSpace(databaseOptions.Value.WorkflowListingObjectType)
            ? "Ferdinand"
            : databaseOptions.Value.WorkflowListingObjectType;

        var jsonPayload = await ExecuteListingJsonAsync(wisagId, objectType, cancellationToken);
        if (string.IsNullOrWhiteSpace(jsonPayload))
        {
            return new WorkflowSourcesResponse { Sources = [] };
        }

        using var document = JsonDocument.Parse(jsonPayload);
        if (!document.RootElement.TryGetProperty("response", out var responseElement))
        {
            return new WorkflowSourcesResponse { Sources = [] };
        }

        if (TryReadMetaCode(responseElement) == 2)
        {
            return new WorkflowSourcesResponse { Sources = [] };
        }

        var sources = new List<SourceBlock>();
        if (!responseElement.TryGetProperty("sources", out var sourcesElement) || sourcesElement.ValueKind != JsonValueKind.Array)
        {
            return new WorkflowSourcesResponse { Sources = sources };
        }

        foreach (var sourceElement in sourcesElement.EnumerateArray())
        {
            if (!sourceElement.TryGetProperty("source", out var sourceNameElement))
            {
                continue;
            }

            var sourceName = sourceNameElement.GetString();
            if (string.Equals(sourceName, "Ferdinand", StringComparison.OrdinalIgnoreCase))
            {
                sources.Add(new FerdinandSourceBlock
                {
                    Source = "Ferdinand",
                    Profile = ReadArray(sourceElement, "profile"),
                    Listing = ReadArray(sourceElement, "Listing"),
                    Approvals = ReadArray(sourceElement, "approvals"),
                    Document = ReadArray(sourceElement, "document"),
                    ClosingMethod = ReadArray(sourceElement, "closing_method"),
                    RejectionReason = ReadArray(sourceElement, "rejection_reason")
                });

                continue;
            }

            if (string.Equals(sourceName, "Contracts", StringComparison.OrdinalIgnoreCase))
            {
                sources.Add(new ContractsSourceBlock
                {
                    Source = "Contracts",
                    Profile = ReadArray(sourceElement, "profile"),
                    Listing = ReadArray(sourceElement, "Listing"),
                    Approvals = ReadArray(sourceElement, "approvals"),
                    Document = ReadArray(sourceElement, "document"),
                    ClosingMethod = ReadArray(sourceElement, "closing_method")
                });
            }
        }

        return new WorkflowSourcesResponse { Sources = sources };
    }

    /// <summary>
    /// Applies a closing decision to a workflow item.
    /// </summary>
    /// <param name="wisagId">WISAG user identifier.</param>
    /// <param name="source">Source system name.</param>
    /// <param name="processId">Process identifier.</param>
    /// <param name="decision">Closing decision payload.</param>
    /// <param name="cancellationToken">Cancellation token.</param>
    /// <returns>Result of the close operation.</returns>
    public Task<CloseWorkflowResult> CloseAsync(
        int wisagId,
        string source,
        int processId,
        CloseWorkflowDecision decision,
        CancellationToken cancellationToken)
    {
        _ = decision;

        if (!string.Equals(source, "Ferdinand", StringComparison.OrdinalIgnoreCase))
        {
            return Task.FromResult(new CloseWorkflowResult
            {
                ProcessId = processId,
                IsClosed = false,
                Outcome = CloseWorkflowOutcome.NotFound
            });
        }

        return EvaluateCloseOutcomeAsync(wisagId, source, processId, cancellationToken);
    }

    private async Task<CloseWorkflowResult> EvaluateCloseOutcomeAsync(
        int wisagId,
        string source,
        int processId,
        CancellationToken cancellationToken)
    {
        var rows = await ExecuteListingTableAsync(wisagId, source, cancellationToken);
        if (rows.Any(row => row.ProcessId == processId))
        {
            return new CloseWorkflowResult
            {
                ProcessId = processId,
                IsClosed = true,
                Outcome = CloseWorkflowOutcome.Closed
            };
        }

        var metaCode = await TryGetWorkflowMetaCodeAsync(wisagId, source, cancellationToken);
        if (metaCode == 2)
        {
            return new CloseWorkflowResult
            {
                ProcessId = processId,
                IsClosed = false,
                Outcome = CloseWorkflowOutcome.NoAccess
            };
        }

        return new CloseWorkflowResult
        {
            ProcessId = 0,
            IsClosed = false,
            Outcome = CloseWorkflowOutcome.NotFound
        };
    }

    private async Task<int?> TryGetWorkflowMetaCodeAsync(int wisagId, string objectType, CancellationToken cancellationToken)
    {
        var jsonPayload = await ExecuteListingJsonAsync(wisagId, objectType, cancellationToken);

        if (string.IsNullOrWhiteSpace(jsonPayload))
        {
            return null;
        }

        try
        {
            using var document = JsonDocument.Parse(jsonPayload);

            return document.RootElement.TryGetProperty("response", out var responseElement)
                ? TryReadMetaCode(responseElement)
                : null;
        }
        catch (JsonException)
        {
            return null;
        }
    }

    private async Task<IReadOnlyList<WorkflowListingReadModel>> ExecuteListingTableAsync(
        int wisagId,
        string objectType,
        CancellationToken cancellationToken)
    {
        const string resultType = "table";

        return await dbContext
            .WorkflowListingReadModels
            .FromSqlInterpolated($"EXEC dbo.PRCUST_F19_GET_LISTING_DATA @pUSER_ID={wisagId}, @pRESULT_TYPE={resultType}, @pOBJECT_TYPE={objectType}")
            .AsNoTracking()
            .ToListAsync(cancellationToken);
    }

    private async Task<string?> ExecuteListingJsonAsync(int wisagId, string objectType, CancellationToken cancellationToken)
    {
        const string commandText = "EXEC dbo.PRCUST_F19_GET_LISTING_DATA @pUSER_ID, @pRESULT_TYPE, @pOBJECT_TYPE";
        const string resultType = "json";

        await using var command = dbContext.Database.GetDbConnection().CreateCommand();
        command.CommandText = commandText;

        command.Parameters.Add(new SqlParameter("@pUSER_ID", wisagId));
        command.Parameters.Add(new SqlParameter("@pRESULT_TYPE", resultType));
        command.Parameters.Add(new SqlParameter("@pOBJECT_TYPE", objectType));

        if (command.Connection is null)
        {
            return null;
        }

        if (command.Connection.State != System.Data.ConnectionState.Open)
        {
            await command.Connection.OpenAsync(cancellationToken);
        }

        await using var reader = await command.ExecuteReaderAsync(cancellationToken);
        if (!await reader.ReadAsync(cancellationToken) || reader.FieldCount == 0 || reader.IsDBNull(0))
        {
            return null;
        }

        return reader.GetString(0);
    }

    private static int? TryReadMetaCode(JsonElement responseElement)
    {
        if (!responseElement.TryGetProperty("meta", out var metaElement) || metaElement.ValueKind != JsonValueKind.Array)
        {
            return null;
        }

        if (metaElement.GetArrayLength() == 0 || !metaElement[0].TryGetProperty("code", out var codeElement))
        {
            return null;
        }

        return codeElement.GetInt32();
    }

    private static IReadOnlyList<JsonElement> ReadArray(JsonElement sourceElement, string propertyName)
    {
        if (!sourceElement.TryGetProperty(propertyName, out var propertyElement) || propertyElement.ValueKind != JsonValueKind.Array)
        {
            return [];
        }

        return propertyElement.EnumerateArray().Select(item => item.Clone()).ToList();
    }
}