using Microsoft.EntityFrameworkCore;
using CredentialManager.Data;
using CredentialManager.Models;
using System.Text.Json;

namespace CredentialManager.Services;

/// <summary>
/// Implementazione del servizio per la gestione dei profili Data Coupler
/// </summary>
public class DataCouplerProfileService : IDataCouplerProfileService
{
    private readonly CredentialDbContext _context;

    public DataCouplerProfileService(CredentialDbContext context)
    {
        _context = context;
    }

    /// <summary>
    /// Ottiene tutti i profili attivi
    /// </summary>
    public async Task<IEnumerable<DataCouplerProfile>> GetAllProfilesAsync()
    {
        return await _context.DataCouplerProfiles
            .Include(p => p.SourceCredential)
            .Include(p => p.DestinationCredential)
            .Where(p => p.IsActive)
            .OrderByDescending(p => p.LastUsedAt)
            .ThenByDescending(p => p.CreatedAt)
            .ToListAsync();
    }

    /// <summary>
    /// Ottiene tutti i profili per nome (inclusi quelli inattivi)
    /// </summary>
    public async Task<DataCouplerProfile?> GetProfileByNameIncludingInactiveAsync(string name)
    {
        return await _context.DataCouplerProfiles
            .Include(p => p.SourceCredential)
            .Include(p => p.DestinationCredential)
            .FirstOrDefaultAsync(p => p.Name.ToLower() == name.ToLower());
    }

    /// <summary>
    /// Ottiene un profilo per ID
    /// </summary>
    public async Task<DataCouplerProfile?> GetProfileByIdAsync(int id)
    {
        return await _context.DataCouplerProfiles
            .Include(p => p.SourceCredential)
            .Include(p => p.DestinationCredential)
            .FirstOrDefaultAsync(p => p.Id == id && p.IsActive);
    }

    /// <summary>
    /// Ottiene un profilo per nome
    /// </summary>
    public async Task<DataCouplerProfile?> GetProfileByNameAsync(string name)
    {
        return await _context.DataCouplerProfiles
            .Include(p => p.SourceCredential)
            .Include(p => p.DestinationCredential)
            .FirstOrDefaultAsync(p => p.Name == name && p.IsActive);
    }

    /// <summary>
    /// Salva un nuovo profilo
    /// </summary>
    public async Task<DataCouplerProfile> SaveProfileAsync(DataCouplerProfile profile)
    {
        profile.CreatedAt = DateTime.UtcNow;
        profile.IsActive = true;

        _context.DataCouplerProfiles.Add(profile);
        await _context.SaveChangesAsync();

        return profile;
    }

    /// <summary>
    /// Aggiorna un profilo esistente
    /// </summary>
    public async Task<DataCouplerProfile> UpdateProfileAsync(DataCouplerProfile profile)
    {
        var existingProfile = await _context.DataCouplerProfiles
            .FirstOrDefaultAsync(p => p.Id == profile.Id);

        if (existingProfile == null)
        {
            throw new InvalidOperationException($"Profilo con ID {profile.Id} non trovato");
        }

        // Aggiorna le proprietà (evita di aggiornare il nome se è uguale per evitare unique constraint)
        if (!string.Equals(existingProfile.Name, profile.Name, StringComparison.OrdinalIgnoreCase))
        {
            existingProfile.Name = profile.Name;
        }
        
        existingProfile.Description = profile.Description;
        existingProfile.SourceType = profile.SourceType;
        existingProfile.SourceCredentialId = profile.SourceCredentialId;
        existingProfile.SourceSchema = profile.SourceSchema;
        existingProfile.SourceTable = profile.SourceTable;
        existingProfile.SourceFilePath = profile.SourceFilePath;
        existingProfile.DestinationType = profile.DestinationType;
        existingProfile.DestinationCredentialId = profile.DestinationCredentialId;
        existingProfile.DestinationSchema = profile.DestinationSchema;
        existingProfile.DestinationTable = profile.DestinationTable;
        existingProfile.DestinationEndpoint = profile.DestinationEndpoint;
        existingProfile.FieldMappingJson = profile.FieldMappingJson;
        existingProfile.SourceKeyField = profile.SourceKeyField;
        existingProfile.UseRecordAssociations = profile.UseRecordAssociations;
        existingProfile.IsActive = profile.IsActive;

        await _context.SaveChangesAsync();
        return existingProfile;
    }

    /// <summary>
    /// Elimina un profilo (soft delete)
    /// </summary>
    public async Task<bool> DeleteProfileAsync(int id)
    {
        var profile = await _context.DataCouplerProfiles
            .FirstOrDefaultAsync(p => p.Id == id);

        if (profile == null)
        {
            return false;
        }

        profile.IsActive = false;
        await _context.SaveChangesAsync();
        return true;
    }

    /// <summary>
    /// Aggiorna la data di ultimo utilizzo di un profilo
    /// </summary>
    public async Task UpdateLastUsedAsync(int id)
    {
        var profile = await _context.DataCouplerProfiles
            .FirstOrDefaultAsync(p => p.Id == id);

        if (profile != null)
        {
            profile.LastUsedAt = DateTime.UtcNow;
            await _context.SaveChangesAsync();
        }
    }

    /// <summary>
    /// Verifica se esiste un profilo con il nome specificato
    /// </summary>
    public async Task<bool> ProfileExistsAsync(string name, int? excludeId = null)
    {
        var query = _context.DataCouplerProfiles
            .Where(p => p.Name == name && p.IsActive);

        if (excludeId.HasValue)
        {
            query = query.Where(p => p.Id != excludeId.Value);
        }

        return await query.AnyAsync();
    }

    /// <summary>
    /// Serializza la lista di mapping dei campi in JSON
    /// </summary>
    public string SerializeFieldMappings(List<FieldMappingDto>? mappings)
    {
        if (mappings == null || !mappings.Any())
            return string.Empty;

        return JsonSerializer.Serialize(mappings, new JsonSerializerOptions 
        { 
            PropertyNamingPolicy = JsonNamingPolicy.CamelCase 
        });
    }

    /// <summary>
    /// Deserializza il JSON dei mapping dei campi
    /// </summary>
    public List<FieldMappingDto> DeserializeFieldMappings(string? json)
    {
        if (string.IsNullOrWhiteSpace(json))
            return new List<FieldMappingDto>();

        try
        {
            return JsonSerializer.Deserialize<List<FieldMappingDto>>(json, new JsonSerializerOptions 
            { 
                PropertyNamingPolicy = JsonNamingPolicy.CamelCase 
            }) ?? new List<FieldMappingDto>();
        }
        catch
        {
            return new List<FieldMappingDto>();
        }
    }

    /// <summary>
    /// Converte un DataCouplerProfile in DTO
    /// </summary>
    public DataCouplerProfileDto ToDto(DataCouplerProfile profile)
    {
        return new DataCouplerProfileDto
        {
            Id = profile.Id,
            Name = profile.Name,
            Description = profile.Description,
            SourceType = profile.SourceType,
            SourceCredentialId = profile.SourceCredentialId,
            SourceCredentialName = profile.SourceCredential?.Name,
            SourceDatabaseName = profile.SourceDatabaseName,
            SourceSchema = profile.SourceSchema,
            SourceTable = profile.SourceTable,
            SourceFilePath = profile.SourceFilePath,
            DestinationType = profile.DestinationType,
            DestinationCredentialId = profile.DestinationCredentialId,
            DestinationCredentialName = profile.DestinationCredential?.Name,
            DestinationSchema = profile.DestinationSchema,
            DestinationTable = profile.DestinationTable,
            DestinationEndpoint = profile.DestinationEndpoint,
            FieldMappings = DeserializeFieldMappings(profile.FieldMappingJson),
            SourceKeyField = profile.SourceKeyField,
            UseRecordAssociations = profile.UseRecordAssociations
        };
    }

    /// <summary>
    /// Converte un DTO in DataCouplerProfile
    /// </summary>
    public DataCouplerProfile FromDto(DataCouplerProfileDto dto, string? createdBy = null)
    {
        return new DataCouplerProfile
        {
            Id = dto.Id ?? 0,
            Name = dto.Name,
            Description = dto.Description,
            SourceType = dto.SourceType,
            SourceCredentialId = dto.SourceCredentialId,
            SourceDatabaseName = dto.SourceDatabaseName,
            SourceSchema = dto.SourceSchema,
            SourceTable = dto.SourceTable,
            SourceFilePath = dto.SourceFilePath,
            DestinationType = dto.DestinationType,
            DestinationCredentialId = dto.DestinationCredentialId,
            DestinationSchema = dto.DestinationSchema,
            DestinationTable = dto.DestinationTable,
            DestinationEndpoint = dto.DestinationEndpoint,
            FieldMappingJson = SerializeFieldMappings(dto.FieldMappings),
            SourceKeyField = dto.SourceKeyField,
            UseRecordAssociations = dto.UseRecordAssociations,
            CreatedBy = createdBy
        };
    }
}