package service

import (
	"context"
	"errors"

	"github.com/gochat/gochat/internal/model"
	"github.com/gochat/gochat/internal/repository"
	applogger "github.com/gochat/gochat/pkg/logger"
	pkgvalidator "github.com/gochat/gochat/pkg/validator"
)

// InstallationConfigService implements business logic for InstallationConfig CRUD.
// Reference: Chatwoot app/controllers/api/v1/platform/installation_configs_controller.rb
type InstallationConfigService struct {
	repo *repository.InstallationConfigRepo
}

// NewInstallationConfigService creates a new InstallationConfig service.
func NewInstallationConfigService(repo *repository.InstallationConfigRepo) *InstallationConfigService {
	return &InstallationConfigService{repo: repo}
}

// --- DTOs for InstallationConfig CRUD ---

// CreateInstallationConfigRequest is the DTO for creating an installation config.
type CreateInstallationConfigRequest struct {
	Name  string `json:"name" validate:"required,min=1,max=100"`
	Value string `json:"value" validate:"required"`
}

// UpdateInstallationConfigRequest is the DTO for updating an installation config.
type UpdateInstallationConfigRequest struct {
	Name  string `json:"name,omitempty" validate:"omitempty,min=1,max=100"`
	Value string `json:"value,omitempty" validate:"omitempty,min=1"`
}

// --- Service methods ---

// Get retrieves an InstallationConfig by ID.
func (s *InstallationConfigService) Get(ctx context.Context, id uint) (*model.InstallationConfig, error) {
	cfg, err := s.repo.FindByID(ctx, id)
	if err != nil {
		applogger.L().Errorf("InstallationConfigService.Get error: %v", err)
		return nil, err
	}
	return cfg, nil
}

// GetByName retrieves an InstallationConfig by name.
func (s *InstallationConfigService) GetByName(ctx context.Context, name string) (*model.InstallationConfig, error) {
	cfg, err := s.repo.FindByName(ctx, name)
	if err != nil {
		applogger.L().Errorf("InstallationConfigService.GetByName error: %v", err)
		return nil, err
	}
	return cfg, nil
}

// List retrieves all installation configs with pagination.
func (s *InstallationConfigService) List(ctx context.Context, offset, limit int) ([]model.InstallationConfig, int64, error) {
	configs, total, err := s.repo.List(ctx, offset, limit)
	if err != nil {
		applogger.L().Errorf("InstallationConfigService.List error: %v", err)
		return nil, 0, err
	}
	return configs, total, nil
}

// Create creates a new installation config.
func (s *InstallationConfigService) Create(ctx context.Context, req *CreateInstallationConfigRequest) (*model.InstallationConfig, error) {
	if err := pkgvalidator.ValidateStruct(req); err != nil {
		return nil, errors.New("validation error: " + err.Error())
	}

	// Check for duplicate name
	existing, err := s.repo.FindByName(ctx, req.Name)
	if err == nil && existing != nil {
		return nil, errors.New("installation config with this name already exists")
	}

	cfg := &model.InstallationConfig{
		Name:  req.Name,
		Value: req.Value,
	}

	if err := s.repo.Create(ctx, cfg); err != nil {
		applogger.L().Errorf("InstallationConfigService.Create error: %v", err)
		return nil, err
	}
	return cfg, nil
}

// Update modifies an existing installation config.
func (s *InstallationConfigService) Update(ctx context.Context, id uint, req *UpdateInstallationConfigRequest) (*model.InstallationConfig, error) {
	if err := pkgvalidator.ValidateStruct(req); err != nil {
		return nil, errors.New("validation error: " + err.Error())
	}

	cfg, err := s.repo.FindByID(ctx, id)
	if err != nil {
		return nil, err
	}

	if req.Name != "" {
		cfg.Name = req.Name
	}
	if req.Value != "" {
		cfg.Value = req.Value
	}

	if err := s.repo.Update(ctx, cfg); err != nil {
		applogger.L().Errorf("InstallationConfigService.Update error: %v", err)
		return nil, err
	}
	return cfg, nil
}

// Delete removes an installation config by ID.
func (s *InstallationConfigService) Delete(ctx context.Context, id uint) error {
	if err := s.repo.Delete(ctx, id); err != nil {
		applogger.L().Errorf("InstallationConfigService.Delete error: %v", err)
		return err
	}
	return nil
}