package automation

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

	"github.com/gochat/gochat/internal/model"
	"github.com/gochat/gochat/internal/worker"
	applogger "github.com/gochat/gochat/pkg/logger"
	"gorm.io/gorm"
)

// MacroService provides CRUD + execution for macros.
// Reference: Chatwoot Macros::ExecutionService — same action handler pattern as AutomationRule,
// but user-originated (supports 'self' assign). stamps user info.
type MacroService struct {
	db     DBProvider
	worker *worker.WorkerPool
}

const TaskTypeMacroExecution = "automation:macro_execution"

// NewMacroService creates a new MacroService.
func NewMacroService(db DBProvider) *MacroService {
	return &MacroService{db: db}
}

func NewMacroServiceWithWorker(db DBProvider, wp *worker.WorkerPool) *MacroService {
	s := NewMacroService(db)
	s.SetWorkerPool(wp)
	return s
}

func (s *MacroService) SetWorkerPool(wp *worker.WorkerPool) {
	s.worker = wp
	RegisterActionDeliveryJobs(wp, s.db)
	RegisterMacroExecutionJobs(wp, s.db)
}

// GetByID retrieves a macro by ID.
func (s *MacroService) GetByID(ctx context.Context, id uint) (*Macro, error) {
	var macro Macro
	if err := s.db.DB().WithContext(ctx).Preload("CreatedBy").Preload("UpdatedBy").First(&macro, id).Error; err != nil {
		return nil, err
	}
	_ = s.hydrateMacroFiles(ctx, &macro)
	return &macro, nil
}

// GetByIDForAccount retrieves a macro scoped to an account.
func (s *MacroService) GetByIDForAccount(ctx context.Context, accountID, id uint) (*Macro, error) {
	var macro Macro
	if err := s.db.DB().WithContext(ctx).
		Preload("CreatedBy").Preload("UpdatedBy").
		Where("account_id = ?", accountID).
		First(&macro, id).Error; err != nil {
		return nil, err
	}
	_ = s.hydrateMacroFiles(ctx, &macro)
	return &macro, nil
}

// ListByAccount retrieves all macros for an account, respecting visibility.
// Personal macros are only visible to their creator; global macros are visible to all.
func (s *MacroService) ListByAccount(ctx context.Context, accountID uint, userID uint) ([]Macro, error) {
	var macros []Macro
	query := s.db.DB().WithContext(ctx).
		Where("account_id = ?", accountID)

	// Filter by visibility: show global macros + personal macros owned by this user
	query = query.Where("visibility = ? OR (visibility = ? AND created_by_id = ?)",
		MacroVisibilityGlobal, MacroVisibilityPersonal, userID)

	if err := query.Preload("CreatedBy").Preload("UpdatedBy").Order("id ASC").Find(&macros).Error; err != nil {
		return nil, err
	}
	for i := range macros {
		_ = s.hydrateMacroFiles(ctx, &macros[i])
	}
	return macros, nil
}

// Create creates a new macro.
func (s *MacroService) Create(ctx context.Context, macro *Macro) error {
	if strings.TrimSpace(macro.Name) == "" {
		return fmt.Errorf("name is required")
	}
	if macro.Actions == nil {
		macro.Actions = Actions{}
	}
	if err := s.normalizeMacroAttachmentActions(ctx, macro.AccountID, &macro.Actions); err != nil {
		return err
	}
	macro.Active = true
	// Use Select to force all fields including zero-value bool Active=false.
	// Without Select, GORM skips zero-value fields and uses column defaults.
	// Callers should explicitly set Active=true when creating new macros.
	if err := s.db.DB().WithContext(ctx).Select(
		"AccountID", "Name", "Actions", "Visibility", "Active",
		"CreatedByID", "UpdatedByID",
	).Create(macro).Error; err != nil {
		return err
	}
	if err := s.db.DB().WithContext(ctx).Preload("CreatedBy").Preload("UpdatedBy").First(macro, macro.ID).Error; err != nil {
		return err
	}
	return s.hydrateMacroFiles(ctx, macro)
}

// Update updates an existing macro.
func (s *MacroService) Update(ctx context.Context, macro *Macro) error {
	return s.db.DB().WithContext(ctx).Save(macro).Error
}

// UpdateForAccount updates an existing macro within account scope while preserving ownership.
func (s *MacroService) UpdateForAccount(ctx context.Context, accountID uint, macro *Macro) (*Macro, error) {
	existing, err := s.GetByIDForAccount(ctx, accountID, macro.ID)
	if err != nil {
		return nil, err
	}
	existing.Name = macro.Name
	if macro.Actions != nil {
		if err := s.normalizeMacroAttachmentActions(ctx, accountID, &macro.Actions); err != nil {
			return nil, err
		}
		existing.Actions = macro.Actions
	}
	existing.Visibility = macro.Visibility
	existing.UpdatedByID = macro.UpdatedByID
	if err := s.Update(ctx, existing); err != nil {
		return nil, err
	}
	return s.GetByIDForAccount(ctx, accountID, existing.ID)
}

func (s *MacroService) normalizeMacroAttachmentActions(ctx context.Context, accountID uint, actions *Actions) error {
	if actions == nil {
		return nil
	}
	for i := range *actions {
		action := &(*actions)[i]
		if action.ActionName != "send_attachment" {
			continue
		}
		if action.ActionParams == nil {
			return fmt.Errorf("invalid attachment")
		}
		blobID := firstMacroBlobID(action.ActionParams)
		upload, err := s.findMacroUpload(ctx, accountID, blobID)
		if err != nil {
			return fmt.Errorf("invalid attachment")
		}
		action.ActionParams["blob_id"] = upload.ID
		delete(action.ActionParams, "attachment_url")
	}
	return nil
}

func firstMacroBlobID(params map[string]interface{}) interface{} {
	if value := params["blob_id"]; value != nil {
		return value
	}
	return params["attachment_url"]
}

func (s *MacroService) findMacroUpload(ctx context.Context, accountID uint, value interface{}) (*model.DirectUpload, error) {
	switch v := value.(type) {
	case string:
		if parsed, err := strconv.ParseUint(v, 10, 64); err == nil {
			return s.findMacroUploadByID(ctx, accountID, uint(parsed))
		}
		var upload model.DirectUpload
		if err := s.db.DB().WithContext(ctx).Where("account_id = ? AND upload_uuid = ?", accountID, v).First(&upload).Error; err != nil {
			return nil, err
		}
		return &upload, nil
	case float64:
		return s.findMacroUploadByID(ctx, accountID, uint(v))
	case int:
		return s.findMacroUploadByID(ctx, accountID, uint(v))
	case uint:
		return s.findMacroUploadByID(ctx, accountID, v)
	case json.Number:
		parsed, err := strconv.ParseUint(string(v), 10, 64)
		if err != nil {
			return nil, err
		}
		return s.findMacroUploadByID(ctx, accountID, uint(parsed))
	default:
		return nil, gorm.ErrRecordNotFound
	}
}

func (s *MacroService) findMacroUploadByID(ctx context.Context, accountID, id uint) (*model.DirectUpload, error) {
	var upload model.DirectUpload
	if err := s.db.DB().WithContext(ctx).Where("account_id = ? AND id = ?", accountID, id).First(&upload).Error; err != nil {
		return nil, err
	}
	return &upload, nil
}

func (s *MacroService) hydrateMacroFiles(ctx context.Context, macro *Macro) error {
	ids := macroAttachmentBlobIDs(macro.Actions)
	if len(ids) == 0 {
		macro.Files = nil
		return nil
	}
	var uploads []model.DirectUpload
	if err := s.db.DB().WithContext(ctx).Where("account_id = ? AND id IN ?", macro.AccountID, ids).Order("id ASC").Find(&uploads).Error; err != nil {
		return err
	}
	files := make([]MacroFile, 0, len(uploads))
	for _, upload := range uploads {
		files = append(files, MacroFile{ID: upload.ID, MacroID: macro.ID, FileType: upload.MimeType, AccountID: upload.AccountID, FileURL: upload.FileURL, BlobID: upload.ID, Filename: upload.OriginalName})
	}
	macro.Files = files
	return nil
}

func macroAttachmentBlobIDs(actions Actions) []uint {
	seen := map[uint]bool{}
	ids := []uint{}
	for _, action := range actions {
		if action.ActionName != "send_attachment" {
			continue
		}
		id := macroBlobIDAsUint(action.ActionParams["blob_id"])
		if id == 0 || seen[id] {
			continue
		}
		seen[id] = true
		ids = append(ids, id)
	}
	return ids
}

func macroBlobIDAsUint(value interface{}) uint {
	switch v := value.(type) {
	case uint:
		return v
	case int:
		return uint(v)
	case float64:
		return uint(v)
	case string:
		parsed, _ := strconv.ParseUint(v, 10, 64)
		return uint(parsed)
	case json.Number:
		parsed, _ := strconv.ParseUint(string(v), 10, 64)
		return uint(parsed)
	default:
		return 0
	}
}

// Delete deletes a macro by ID.
func (s *MacroService) Delete(ctx context.Context, id uint) error {
	return s.db.DB().WithContext(ctx).Delete(&Macro{}, id).Error
}

// DeleteForAccount deletes a macro within account scope.
func (s *MacroService) DeleteForAccount(ctx context.Context, accountID, id uint) error {
	macro, err := s.GetByIDForAccount(ctx, accountID, id)
	if err != nil {
		return err
	}
	return s.db.DB().WithContext(ctx).Delete(macro).Error
}

// Clone creates a copy of a macro with "(copy)" appended to the name.
// Reference: Chatwoot Macro clone — duplicates actions, resets ID, stamps creator.
func (s *MacroService) Clone(ctx context.Context, id uint) (*Macro, error) {
	original, err := s.GetByID(ctx, id)
	if err != nil {
		return nil, fmt.Errorf("failed to load macro %d for clone: %w", id, err)
	}

	cloned := &Macro{
		AccountID:   original.AccountID,
		Name:        original.Name + " (copy)",
		Actions:     original.Actions,
		Visibility:  original.Visibility,
		Active:      original.Active,
		CreatedByID: original.CreatedByID,
		UpdatedByID: original.UpdatedByID,
	}

	if err := s.Create(ctx, cloned); err != nil {
		return nil, fmt.Errorf("failed to create cloned macro: %w", err)
	}
	return cloned, nil
}

// ToggleActive flips the active state of a macro.
func (s *MacroService) ToggleActive(ctx context.Context, id uint, active bool) error {
	return s.db.DB().WithContext(ctx).
		Model(&Macro{}).
		Where("id = ?", id).
		Update("active", active).Error
}

// Execute runs a macro's actions on a conversation.
// Reference: Chatwoot Macros::ExecutionService stamps user info (executed_by)
// and supports 'self' assignment (assign to the user running the macro).
// Template variables in action params (e.g. {{contact.name}}) are resolved
// by ActionService before execution — the macro layer injects _source_user_id
// for 'self' assignment support and delegates execution to ActionService.
func (s *MacroService) Execute(ctx context.Context, accountID uint, conversationID uint, macroID uint, userID uint) error {
	macro, err := s.GetByID(ctx, macroID)
	if err != nil {
		return fmt.Errorf("failed to load macro %d: %w", macroID, err)
	}

	applogger.L().Infof("executing macro %d (%s) on conversation %d by user %d", macro.ID, macro.Name, conversationID, userID)

	actionSvc := NewActionServiceWithWorker(s.db, s.worker)

	for _, action := range macro.Actions {
		// Inject _source_user_id for "self" assignment support
		params := action.ActionParams
		if params == nil {
			params = map[string]interface{}{}
		}
		params["_source_user_id"] = userID

		resolvedAction := Action{
			ActionName:   action.ActionName,
			ActionParams: params,
		}

		// ActionService.Execute resolves template variables internally
		// ({{contact.name}}, {{conversation.status}}, etc.) before running the action.
		if err := actionSvc.Execute(ctx, accountID, conversationID, resolvedAction, ActionSourceMacro, userID); err != nil {
			applogger.L().Errorf("macro action %s failed for macro %d on conversation %d: %v", action.ActionName, macroID, conversationID, err)
			// Continue executing remaining actions (Chatwoot pattern)
		}
	}

	// Stamp execution record for audit trail
	// Reference: Chatwoot stamps user info (executed_by_id)
	return s.recordExecution(ctx, macroID, conversationID, userID)
}

// ExecuteForDisplayIDs runs a macro against account-scoped conversation display IDs.
// Reference: Chatwoot MacrosExecutionJob resolves account.conversations by display_id.
func (s *MacroService) ExecuteForDisplayIDs(ctx context.Context, accountID uint, macroID uint, displayIDs []uint, userID uint) error {
	if s.worker != nil {
		return s.enqueueExecuteForDisplayIDs(ctx, accountID, macroID, displayIDs, userID)
	}
	return s.executeForDisplayIDsNow(ctx, accountID, macroID, displayIDs, userID)
}

func (s *MacroService) enqueueExecuteForDisplayIDs(ctx context.Context, accountID uint, macroID uint, displayIDs []uint, userID uint) error {
	if len(displayIDs) == 0 {
		return nil
	}
	_, err := s.GetByIDForAccount(ctx, accountID, macroID)
	if err != nil {
		return err
	}
	_, err = s.worker.Enqueue(ctx, TaskTypeMacroExecution, macroExecutionJob{
		AccountID:       accountID,
		MacroID:         macroID,
		ConversationIDs: displayIDs,
		UserID:          userID,
	}, worker.WithQueue("medium"), worker.WithMaxAttempts(3))
	return err
}

func (s *MacroService) executeForDisplayIDsNow(ctx context.Context, accountID uint, macroID uint, displayIDs []uint, userID uint) error {
	macro, err := s.GetByIDForAccount(ctx, accountID, macroID)
	if err != nil {
		return err
	}
	if len(displayIDs) == 0 {
		return nil
	}

	var conversations []model.Conversation
	if err := s.db.DB().WithContext(ctx).
		Where("account_id = ? AND display_id IN ?", accountID, displayIDs).
		Find(&conversations).Error; err != nil {
		return err
	}
	if len(conversations) == 0 {
		return nil
	}

	actionSvc := NewActionServiceWithWorker(s.db, s.worker)
	for _, conversation := range conversations {
		applogger.L().Infof("executing macro %d (%s) on conversation %d by user %d", macro.ID, macro.Name, conversation.ID, userID)
		for _, action := range macro.Actions {
			params := map[string]interface{}{}
			for key, value := range action.ActionParams {
				params[key] = value
			}
			params["_source_user_id"] = userID
			resolvedAction := Action{ActionName: action.ActionName, ActionParams: params}
			if err := actionSvc.Execute(ctx, accountID, conversation.ID, resolvedAction, ActionSourceMacro, userID); err != nil {
				applogger.L().Errorf("macro action %s failed for macro %d on conversation %d: %v", action.ActionName, macroID, conversation.ID, err)
			}
		}
		if err := s.recordExecution(ctx, macroID, conversation.ID, userID); err != nil && err != gorm.ErrRecordNotFound {
			applogger.L().Warnf("failed to record macro %d execution for conversation %d: %v", macroID, conversation.ID, err)
		}
	}
	return nil
}

// CanAccess matches Chatwoot MacroPolicy for show/update/destroy/execute.
func (s *MacroService) CanAccess(macro *Macro, userID uint, role string, action string) bool {
	if macro == nil {
		return false
	}
	if action == "show" || action == "execute" {
		return macro.Visibility == MacroVisibilityGlobal || macro.CreatedByID == userID
	}
	if action == "update" || action == "destroy" {
		if macro.Visibility == MacroVisibilityGlobal {
			return role == "administrator" || role == "super_admin"
		}
		return macro.CreatedByID == userID
	}
	return false
}

// recordExecution logs that a macro was executed on a conversation by a user.
func (s *MacroService) recordExecution(ctx context.Context, macroID, conversationID, userID uint) error {
	record := &MacroExecution{
		MacroID:        macroID,
		ConversationID: conversationID,
		ExecutedByID:   userID,
	}
	return s.db.DB().WithContext(ctx).Create(record).Error
}

// MacroExecution records a macro execution event for audit trail.
type MacroExecution struct {
	ID             uint `gorm:"primaryKey;autoIncrement" json:"id"`
	MacroID        uint `gorm:"index;not null" json:"macro_id"`
	ConversationID uint `gorm:"index;not null" json:"conversation_id"`
	ExecutedByID   uint `gorm:"index;not null" json:"executed_by_id"`
}

func (MacroExecution) TableName() string { return "macro_executions" }