package service

import (
	"context"
	"encoding/json"
	"fmt"

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

// CaptainScenarioService implements business logic for CaptainScenario operations.
// Reference: Chatwoot enterprise/app/controllers/api/v1/captain/scenarios_controller.rb
type CaptainScenarioService struct {
	scenarioRepo  *repository.CaptainScenarioRepo
	assistantRepo *repository.CaptainAssistantRepo
}

// NewCaptainScenarioService creates a new CaptainScenarioService.
func NewCaptainScenarioService(scenarioRepo *repository.CaptainScenarioRepo, assistantRepo ...*repository.CaptainAssistantRepo) *CaptainScenarioService {
	s := &CaptainScenarioService{scenarioRepo: scenarioRepo}
	if len(assistantRepo) > 0 {
		s.assistantRepo = assistantRepo[0]
	}
	return s
}

// --- Request DTOs ---

// CreateScenarioRequest is the DTO for creating a scenario.
type CreateScenarioRequest struct {
	Title       string          `json:"title" validate:"required"`
	Description string          `json:"description"`
	Instruction string          `json:"instruction"`
	Enabled     *bool           `json:"enabled"`
	Tools       json.RawMessage `json:"tools"`
}

// UpdateScenarioRequest is the DTO for updating a scenario.
type UpdateScenarioRequest struct {
	Title       string          `json:"title"`
	Description string          `json:"description"`
	Instruction string          `json:"instruction"`
	Enabled     *bool           `json:"enabled"`
	Tools       json.RawMessage `json:"tools"`
}

// --- Service methods ---

// Create creates a new scenario for an assistant.
func (s *CaptainScenarioService) Create(ctx context.Context, accountID, assistantID uint, req *CreateScenarioRequest) (*model.CaptainScenario, error) {
	if s.assistantRepo != nil {
		if _, err := s.assistantRepo.GetByAccountAndID(ctx, accountID, assistantID); err != nil {
			return nil, fmt.Errorf("assistant not found: %w", err)
		}
	}
	enabled := true
	if req.Enabled != nil {
		enabled = *req.Enabled
	}
	scenario := &model.CaptainScenario{
		AccountID:   accountID,
		AssistantID: assistantID,
		Title:       req.Title,
		Description: req.Description,
		Instruction: req.Instruction,
		Enabled:     enabled,
		Tools:       req.Tools,
	}

	if err := s.scenarioRepo.Create(ctx, scenario); err != nil {
		applogger.L().Errorf("Create captain scenario: %v", err)
		return nil, fmt.Errorf("create scenario: %w", err)
	}
	if created, err := s.scenarioRepo.GetByAccountAssistantAndID(ctx, accountID, assistantID, scenario.ID); err == nil {
		return created, nil
	}
	return scenario, nil
}

func (s *CaptainScenarioService) Get(ctx context.Context, accountID, assistantID, id uint) (*model.CaptainScenario, error) {
	scenario, err := s.scenarioRepo.GetByAccountAssistantAndID(ctx, accountID, assistantID, id)
	if err != nil {
		applogger.L().Errorf("Get captain scenario: %v", err)
		return nil, fmt.Errorf("get scenario: %w", err)
	}
	return scenario, nil
}

// GetByID retrieves a scenario by ID.
func (s *CaptainScenarioService) GetByID(ctx context.Context, id uint) (*model.CaptainScenario, error) {
	scenario, err := s.scenarioRepo.GetByID(ctx, id)
	if err != nil {
		applogger.L().Errorf("Get captain scenario: %v", err)
		return nil, fmt.Errorf("get scenario: %w", err)
	}
	return scenario, nil
}

// Update updates an existing scenario.
func (s *CaptainScenarioService) Update(ctx context.Context, id uint, req *UpdateScenarioRequest) (*model.CaptainScenario, error) {
	scenario, err := s.scenarioRepo.GetByID(ctx, id)
	if err != nil {
		return nil, fmt.Errorf("scenario not found: %w", err)
	}

	if req.Title != "" {
		scenario.Title = req.Title
	}
	if req.Description != "" {
		scenario.Description = req.Description
	}
	if req.Instruction != "" {
		scenario.Instruction = req.Instruction
	}
	if req.Enabled != nil {
		scenario.Enabled = *req.Enabled
	}
	if len(req.Tools) > 0 && string(req.Tools) != "null" {
		scenario.Tools = req.Tools
	}

	if err := s.scenarioRepo.Update(ctx, scenario); err != nil {
		applogger.L().Errorf("Update captain scenario: %v", err)
		return nil, fmt.Errorf("update scenario: %w", err)
	}
	return scenario, nil
}

func (s *CaptainScenarioService) UpdateScoped(ctx context.Context, accountID, assistantID, id uint, req *UpdateScenarioRequest) (*model.CaptainScenario, error) {
	scenario, err := s.scenarioRepo.GetByAccountAssistantAndID(ctx, accountID, assistantID, id)
	if err != nil {
		return nil, fmt.Errorf("scenario not found: %w", err)
	}

	if req.Title != "" {
		scenario.Title = req.Title
	}
	if req.Description != "" {
		scenario.Description = req.Description
	}
	if req.Instruction != "" {
		scenario.Instruction = req.Instruction
	}
	if req.Enabled != nil {
		scenario.Enabled = *req.Enabled
	}
	if len(req.Tools) > 0 && string(req.Tools) != "null" {
		scenario.Tools = req.Tools
	}

	if err := s.scenarioRepo.Update(ctx, scenario); err != nil {
		applogger.L().Errorf("Update captain scenario: %v", err)
		return nil, fmt.Errorf("update scenario: %w", err)
	}
	return scenario, nil
}

// Delete deletes a scenario by ID.
func (s *CaptainScenarioService) Delete(ctx context.Context, id uint) error {
	if err := s.scenarioRepo.Delete(ctx, id); err != nil {
		applogger.L().Errorf("Delete captain scenario: %v", err)
		return fmt.Errorf("delete scenario: %w", err)
	}
	return nil
}

func (s *CaptainScenarioService) DeleteScoped(ctx context.Context, accountID, assistantID, id uint) error {
	if _, err := s.scenarioRepo.GetByAccountAssistantAndID(ctx, accountID, assistantID, id); err != nil {
		return fmt.Errorf("scenario not found: %w", err)
	}
	if err := s.scenarioRepo.DeleteByAccountAssistant(ctx, accountID, assistantID, id); err != nil {
		applogger.L().Errorf("Delete captain scenario: %v", err)
		return fmt.Errorf("delete scenario: %w", err)
	}
	return nil
}

// ListByAssistant retrieves scenarios for an assistant with pagination.
func (s *CaptainScenarioService) ListByAssistant(ctx context.Context, assistantID uint, offset, limit int) ([]model.CaptainScenario, int64, error) {
	scenarios, count, err := s.scenarioRepo.ListByAssistant(ctx, assistantID, offset, limit)
	if err != nil {
		applogger.L().Errorf("List captain scenarios: %v", err)
		return nil, 0, fmt.Errorf("list scenarios: %w", err)
	}
	return scenarios, count, nil
}

func (s *CaptainScenarioService) ListByAccountAssistant(ctx context.Context, accountID, assistantID uint) ([]model.CaptainScenario, int64, error) {
	if s.assistantRepo != nil {
		if _, err := s.assistantRepo.GetByAccountAndID(ctx, accountID, assistantID); err != nil {
			return nil, 0, fmt.Errorf("assistant not found: %w", err)
		}
	}
	scenarios, count, err := s.scenarioRepo.ListEnabledByAccountAssistant(ctx, accountID, assistantID)
	if err != nil {
		applogger.L().Errorf("List captain scenarios: %v", err)
		return nil, 0, fmt.Errorf("list scenarios: %w", err)
	}
	return scenarios, count, nil
}