using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading.Tasks;
using Erp.SqlQueryManager.Application.Contracts;
using Erp.SqlQueryManager.Domain.Entities;
using Erp.SqlQueryManager.Domain.Services;
using Erp.SqlQueryManager.Domain.Shared;
using Microsoft.AspNetCore.Mvc;
using Volo.Abp.Application.Services;
using Volo.Abp.Domain.Repositories;

namespace Erp.SqlQueryManager.Application;

/// <summary>
/// Unified service for SQL Object Explorer
/// Combines all SQL objects into a single endpoint
/// </summary>
public class SqlObjectManagerAppService : ApplicationService, ISqlObjectManagerAppService
{
    private readonly IRepository<SqlQuery, Guid> _queryRepository;
    private readonly IRepository<SqlStoredProcedure, Guid> _procedureRepository;
    private readonly IRepository<SqlView, Guid> _viewRepository;
    private readonly IRepository<SqlFunction, Guid> _functionRepository;
    private readonly ISqlExecutorService _sqlExecutorService;
    private readonly ISqlTemplateProvider _templateProvider;

    public SqlObjectManagerAppService(
        IRepository<SqlQuery, Guid> queryRepository,
        IRepository<SqlStoredProcedure, Guid> procedureRepository,
        IRepository<SqlView, Guid> viewRepository,
        IRepository<SqlFunction, Guid> functionRepository,
        ISqlExecutorService sqlExecutorService,
        ISqlTemplateProvider templateProvider)
    {
        _queryRepository = queryRepository;
        _procedureRepository = procedureRepository;
        _viewRepository = viewRepository;
        _functionRepository = functionRepository;
        _sqlExecutorService = sqlExecutorService;
        _templateProvider = templateProvider;
    }

    public async Task<SqlObjectExplorerDto> GetAllObjectsAsync(string dataSourceCode)
    {
        var result = new SqlObjectExplorerDto();

        // Get all queries for this data source
        var queries = await _queryRepository.GetListAsync();
        result.Queries = queries
            .Where(q => q.DataSourceCode == dataSourceCode)
            .Select(q => new SqlQueryDto
            {
                Id = q.Id,
                Code = q.Code,
                Name = q.Name,
                Description = q.Description,
                QueryText = q.QueryText,
                DataSourceCode = q.DataSourceCode,
                Status = q.Status,
                Category = q.Category,
                Tags = q.Tags,
                IsModifyingData = q.IsModifyingData,
                Parameters = q.Parameters,
                ExecutionCount = q.ExecutionCount,
                LastExecutedAt = q.LastExecutedAt
            })
            .ToList();

        // Get all stored procedures for this data source
        var procedures = await _procedureRepository.GetListAsync();
        result.StoredProcedures = procedures
            .Where(p => p.DataSourceCode == dataSourceCode)
            .Select(p => new SqlStoredProcedureDto
            {
                Id = p.Id,
                ProcedureName = p.ProcedureName,
                SchemaName = p.SchemaName,
                DisplayName = p.DisplayName,
                Description = p.Description,
                ProcedureBody = p.ProcedureBody,
                DataSourceCode = p.DataSourceCode,
                Category = p.Category,
                Parameters = p.Parameters,
                IsDeployed = p.IsDeployed,
                LastDeployedAt = p.LastDeployedAt
            })
            .ToList();

        // Get all views for this data source
        var views = await _viewRepository.GetListAsync();
        result.Views = views
            .Where(v => v.DataSourceCode == dataSourceCode)
            .Select(v => new SqlViewDto
            {
                Id = v.Id,
                ViewName = v.ViewName,
                SchemaName = v.SchemaName,
                DisplayName = v.DisplayName,
                Description = v.Description,
                ViewDefinition = v.ViewDefinition,
                DataSourceCode = v.DataSourceCode,
                Category = v.Category,
                WithSchemaBinding = v.WithSchemaBinding,
                IsDeployed = v.IsDeployed,
                LastDeployedAt = v.LastDeployedAt
            })
            .ToList();

        // Get all functions for this data source
        var functions = await _functionRepository.GetListAsync();
        result.Functions = functions
            .Where(f => f.DataSourceCode == dataSourceCode)
            .Select(f => new SqlFunctionDto
            {
                Id = f.Id,
                FunctionName = f.FunctionName,
                SchemaName = f.SchemaName,
                DisplayName = f.DisplayName,
                Description = f.Description,
                FunctionType = f.FunctionType,
                FunctionBody = f.FunctionBody,
                ReturnType = f.ReturnType,
                DataSourceCode = f.DataSourceCode,
                Category = f.Category,
                Parameters = f.Parameters,
                IsDeployed = f.IsDeployed,
                LastDeployedAt = f.LastDeployedAt
            })
            .ToList();

        // Get all database tables
        result.Tables = await GetTablesAsync(dataSourceCode);

        // Get all templates
        result.Templates = _templateProvider.GetAvailableQueryTemplates()
            .Select(t => new SqlTemplateDto
            {
                Type = t.Type,
                Name = t.Name,
                Description = t.Description,
                Template = _templateProvider.GetQueryTemplate(t.Type)
            })
            .ToList();

        return result;
    }

    private async Task<List<DatabaseTableDto>> GetTablesAsync(string dataSourceCode)
    {
        var query = @"
            SELECT 
                SCHEMA_NAME(t.schema_id) AS SchemaName,
                t.name AS TableName
            FROM 
                sys.tables t
            WHERE 
                t.is_ms_shipped = 0
            ORDER BY 
                SCHEMA_NAME(t.schema_id), t.name";

        var result = await _sqlExecutorService.ExecuteQueryAsync(query, dataSourceCode);
        
        var tables = new List<DatabaseTableDto>();
        if (result.Success && result.Data != null)
        {
            foreach (var row in result.Data)
            {
                var dict = row as System.Collections.Generic.IDictionary<string, object>;
                if (dict != null)
                {
                    tables.Add(new DatabaseTableDto
                    {
                        SchemaName = dict["SchemaName"]?.ToString() ?? "dbo",
                        TableName = dict["TableName"]?.ToString() ?? ""
                    });
                }
            }
        }

        return tables;
    }

    #region Query Operations

    public async Task<SqlQueryDto> CreateQueryAsync(CreateSqlQueryDto input)
    {
        var query = ObjectMapper.Map<CreateSqlQueryDto, SqlQuery>(input);
        query.Status = SqlQueryStatus.Draft;

        var created = await _queryRepository.InsertAsync(query, autoSave: true);
        return ObjectMapper.Map<SqlQuery, SqlQueryDto>(created);
    }

    public async Task<SqlQueryDto> UpdateQueryAsync(Guid id, UpdateSqlQueryDto input)
    {
        var query = await _queryRepository.GetAsync(id);
        
        query.Name = input.Name;
        query.Description = input.Description;
        query.QueryText = input.QueryText;
        query.Category = input.Category;
        query.Tags = input.Tags;

        var updated = await _queryRepository.UpdateAsync(query, autoSave: true);
        return ObjectMapper.Map<SqlQuery, SqlQueryDto>(updated);
    }

    public async Task DeleteQueryAsync(Guid id)
    {
        await _queryRepository.DeleteAsync(id);
    }

    public async Task<SqlQueryExecutionResultDto> ExecuteQueryAsync(ExecuteSqlQueryDto input)
    {
        var result = await _sqlExecutorService.ExecuteQueryAsync(input.QueryText, input.DataSourceCode);
        return MapExecutionResult(result);
    }

    public async Task<SqlQueryExecutionResultDto> ExecuteSavedQueryAsync(Guid id)
    {
        var query = await _queryRepository.GetAsync(id);
        var result = await _sqlExecutorService.ExecuteQueryAsync(query.QueryText, query.DataSourceCode);
        
        // Update execution statistics
        query.ExecutionCount++;
        query.LastExecutedAt = DateTime.UtcNow;
        await _queryRepository.UpdateAsync(query, autoSave: true);
        
        return MapExecutionResult(result);
    }

    #endregion

    #region Stored Procedure Operations

    public async Task<SqlStoredProcedureDto> UpdateStoredProcedureAsync(Guid id, UpdateSqlStoredProcedureDto input)
    {
        var procedure = await _procedureRepository.GetAsync(id);
        
        procedure.DisplayName = input.DisplayName;
        procedure.Description = input.Description;
        procedure.ProcedureBody = input.ProcedureBody;
        procedure.Category = input.Category;

        var updated = await _procedureRepository.UpdateAsync(procedure, autoSave: true);
        return ObjectMapper.Map<SqlStoredProcedure, SqlStoredProcedureDto>(updated);
    }

    public async Task DeleteStoredProcedureAsync(Guid id)
    {
        await _procedureRepository.DeleteAsync(id);
    }

    public async Task<SqlQueryExecutionResultDto> DeployStoredProcedureAsync(DeployStoredProcedureDto input)
    {
        var procedure = await _procedureRepository.GetAsync(input.Id);
        var result = await _sqlExecutorService.DeployStoredProcedureAsync(
            procedure.ProcedureBody,
            procedure.DataSourceCode
        );

        if (result.Success)
        {
            procedure.IsDeployed = true;
            procedure.LastDeployedAt = DateTime.UtcNow;
            await _procedureRepository.UpdateAsync(procedure, autoSave: true);
        }

        return MapExecutionResult(result);
    }

    #endregion

    #region View Operations

    public async Task<SqlViewDto> UpdateViewAsync(Guid id, UpdateSqlViewDto input)
    {
        var view = await _viewRepository.GetAsync(id);
        
        view.DisplayName = input.DisplayName;
        view.Description = input.Description;
        view.ViewDefinition = input.ViewDefinition;
        view.Category = input.Category;

        var updated = await _viewRepository.UpdateAsync(view, autoSave: true);
        return ObjectMapper.Map<SqlView, SqlViewDto>(updated);
    }

    public async Task DeleteViewAsync(Guid id)
    {
        await _viewRepository.DeleteAsync(id);
    }

    public async Task<SqlQueryExecutionResultDto> DeployViewAsync(DeployViewDto input)
    {
        var view = await _viewRepository.GetAsync(input.Id);
        var result = await _sqlExecutorService.DeployViewAsync(
            view.ViewDefinition,
            view.DataSourceCode
        );

        if (result.Success)
        {
            view.IsDeployed = true;
            view.LastDeployedAt = DateTime.UtcNow;
            await _viewRepository.UpdateAsync(view, autoSave: true);
        }

        return MapExecutionResult(result);
    }

    #endregion

    #region Function Operations

    public async Task<SqlFunctionDto> UpdateFunctionAsync(Guid id, UpdateSqlFunctionDto input)
    {
        var function = await _functionRepository.GetAsync(id);
        
        function.DisplayName = input.DisplayName;
        function.Description = input.Description;
        function.FunctionBody = input.FunctionBody;
        function.Category = input.Category;

        var updated = await _functionRepository.UpdateAsync(function, autoSave: true);
        return ObjectMapper.Map<SqlFunction, SqlFunctionDto>(updated);
    }

    public async Task DeleteFunctionAsync(Guid id)
    {
        await _functionRepository.DeleteAsync(id);
    }

    public async Task<SqlQueryExecutionResultDto> DeployFunctionAsync(DeployFunctionDto input)
    {
        var function = await _functionRepository.GetAsync(input.Id);
        var result = await _sqlExecutorService.DeployFunctionAsync(
            function.FunctionBody,
            function.DataSourceCode
        );

        if (result.Success)
        {
            function.IsDeployed = true;
            function.LastDeployedAt = DateTime.UtcNow;
            await _functionRepository.UpdateAsync(function, autoSave: true);
        }

        return MapExecutionResult(result);
    }

    #endregion

    #region Database Metadata Operations

    public async Task<List<DatabaseColumnDto>> GetTableColumnsAsync(string dataSourceCode, string schemaName, string tableName)
    {
        var query = $@"
            SELECT 
                c.name AS ColumnName,
                TYPE_NAME(c.user_type_id) AS DataType,
                c.is_nullable AS IsNullable,
                c.max_length AS MaxLength
            FROM 
                sys.columns c
                INNER JOIN sys.tables t ON c.object_id = t.object_id
                INNER JOIN sys.schemas s ON t.schema_id = s.schema_id
            WHERE 
                s.name = '{schemaName}'
                AND t.name = '{tableName}'
            ORDER BY 
                c.column_id";

        var result = await _sqlExecutorService.ExecuteQueryAsync(query, dataSourceCode);
        
        var columns = new List<DatabaseColumnDto>();
        if (result.Success && result.Data != null)
        {
            foreach (var row in result.Data)
            {
                var dict = row as System.Collections.Generic.IDictionary<string, object>;
                if (dict != null)
                {
                    columns.Add(new DatabaseColumnDto
                    {
                        ColumnName = dict["ColumnName"]?.ToString() ?? "",
                        DataType = dict["DataType"]?.ToString() ?? "",
                        IsNullable = dict["IsNullable"] is bool b && b,
                        MaxLength = dict["MaxLength"] != null ? int.Parse(dict["MaxLength"].ToString()) : null
                    });
                }
            }
        }

        return columns;
    }

    #endregion

    #region Helper Methods

    private SqlQueryExecutionResultDto MapExecutionResult(SqlExecutionResult result)
    {
        return new SqlQueryExecutionResultDto
        {
            Success = result.Success,
            Message = result.Message,
            Data = result.Data,
            RowsAffected = result.RowsAffected,
            ExecutionTimeMs = result.ExecutionTimeMs,
            Metadata = result.Metadata
        };
    }

    #endregion
}