package automation

import (
	"context"
	"fmt"
	"time"

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

// DBProvider provides database access — implemented by app.App to break the import cycle.
type DBProvider interface {
	DB() *gorm.DB
}

// AutomationRuleService provides CRUD + condition matching + action execution for automation rules.
// Reference: Chatwoot AutomationRules::ActionService + ConditionsFilterService pattern
type AutomationRuleService struct {
	db DBProvider
}

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

// GetByID retrieves an automation rule by ID.
func (s *AutomationRuleService) GetByID(ctx context.Context, id uint) (*AutomationRule, error) {
	var rule AutomationRule
	if err := s.db.DB().WithContext(ctx).First(&rule, id).Error; err != nil {
		return nil, err
	}
	return &rule, nil
}

// ListByAccount retrieves all automation rules for an account.
func (s *AutomationRuleService) ListByAccount(ctx context.Context, accountID uint) ([]AutomationRule, error) {
	var rules []AutomationRule
	if err := s.db.DB().WithContext(ctx).
		Where("account_id = ?", accountID).
		Order("id ASC").
		Find(&rules).Error; err != nil {
		return nil, err
	}
	return rules, nil
}

// ListActiveByAccountAndEvent retrieves active automation rules for a given account and event.
// Reference: Chatwoot AutomationRuleListener loads rules matching event_name
func (s *AutomationRuleService) ListActiveByAccountAndEvent(ctx context.Context, accountID uint, eventName string) ([]AutomationRule, error) {
	var rules []AutomationRule
	if err := s.db.DB().WithContext(ctx).
		Where("account_id = ? AND event_name = ? AND active = ?", accountID, eventName, true).
		Order("id ASC").
		Find(&rules).Error; err != nil {
		return nil, err
	}
	return rules, nil
}

// Create creates a new automation rule.
// New rules default to active unless explicitly set to inactive.
func (s *AutomationRuleService) Create(ctx context.Context, rule *AutomationRule) error {
	// Validate conditions before saving
	if err := ValidateConditions(rule.Conditions); err != nil {
		return fmt.Errorf("invalid conditions: %w", err)
	}
	// Validate actions before saving
	if err := ValidateActions(rule.Actions); err != nil {
		return fmt.Errorf("invalid actions: %w", err)
	}
	// Use Select to force all fields including zero-value bool Active=false
	// Without Select, GORM skips zero-value fields and uses column defaults.
	return s.db.DB().WithContext(ctx).Select(
		"AccountID", "EventName", "Name", "Description",
		"Conditions", "Actions", "Active",
	).Create(rule).Error
}

// Update updates an existing automation rule.
func (s *AutomationRuleService) Update(ctx context.Context, rule *AutomationRule) error {
	// Validate conditions before saving
	if err := ValidateConditions(rule.Conditions); err != nil {
		return fmt.Errorf("invalid conditions: %w", err)
	}
	// Validate actions before saving
	if err := ValidateActions(rule.Actions); err != nil {
		return fmt.Errorf("invalid actions: %w", err)
	}
	return s.db.DB().WithContext(ctx).Save(rule).Error
}

// Delete soft-deletes an automation rule.
func (s *AutomationRuleService) Delete(ctx context.Context, id uint) error {
	return s.db.DB().WithContext(ctx).Delete(&AutomationRule{}, id).Error
}

// Clone duplicates an automation rule, creating a new copy with "(copy)" suffix and Active=false.
// Reference: Chatwoot AutomationRulesController#clone
func (s *AutomationRuleService) Clone(ctx context.Context, id uint) (*AutomationRule, error) {
	original, err := s.GetByID(ctx, id)
	if err != nil {
		return nil, err
	}

	cloned := &AutomationRule{
		AccountID:   original.AccountID,
		EventName:   original.EventName,
		Name:        original.Name + " (copy)",
		Description: original.Description,
		Conditions:  original.Conditions,
		Actions:     original.Actions,
		Active:      false,
	}

	if err := s.db.DB().WithContext(ctx).Create(cloned).Error; err != nil {
		return nil, err
	}

	return cloned, nil
}

// ToggleActive toggles the active state of an automation rule and sets the corresponding timestamp.
func (s *AutomationRuleService) ToggleActive(ctx context.Context, id uint, active bool) error {
	now := time.Now()
	updates := map[string]interface{}{
		"active": active,
	}
	if active {
		updates["active_at"] = &now
		updates["inactive_at"] = nil
	} else {
		updates["inactive_at"] = &now
		updates["active_at"] = nil
	}
	return s.db.DB().WithContext(ctx).
		Model(&AutomationRule{}).
		Where("id = ?", id).
		Updates(updates).Error
}

// MatchAndExecute checks all active rules for the given event and account,
// runs condition filters for each rule, and executes actions for matching rules.
// Reference: Chatwoot AutomationRuleListener — loads rules, runs ConditionsFilterService, then ActionService
func (s *AutomationRuleService) MatchAndExecute(ctx context.Context, accountID uint, eventName string, conversationID uint, eventData map[string]interface{}) error {
	rules, err := s.ListActiveByAccountAndEvent(ctx, accountID, eventName)
	if err != nil {
		return fmt.Errorf("failed to load automation rules: %w", err)
	}

	if len(rules) == 0 {
		applogger.L().Debugf("no active automation rules for account %d event %s", accountID, eventName)
		return nil
	}

	// Load the conversation for condition matching
	conversation, err := s.loadConversation(ctx, conversationID)
	if err != nil {
		return fmt.Errorf("failed to load conversation %d: %w", conversationID, err)
	}

	actionSvc := NewActionService(s.db)

	for _, rule := range rules {
		matched, err := MatchConditions(ctx, s.db.DB(), rule.Conditions, conversation, eventData)
		if err != nil {
			applogger.L().Errorf("condition matching failed for rule %d: %v", rule.ID, err)
			continue
		}
		if !matched {
			applogger.L().Debugf("rule %d did not match conditions for conversation %d", rule.ID, conversationID)
			continue
		}

		applogger.L().Infof("automation rule %d matched for conversation %d, executing %d actions", rule.ID, conversationID, len(rule.Actions))

		// Stamp automation_rule_id on actions for audit trail
		// Reference: Chatwoot AutomationRules::ActionService stamps automation_rule_id
		actionsExecuted := 0
		actionsFailed := 0
		var firstErrorMsg string
		for _, action := range rule.Actions {
			if err := actionSvc.Execute(ctx, accountID, conversationID, action, ActionSourceAutomation, rule.ID); err != nil {
				applogger.L().Errorf("action %s failed for rule %d on conversation %d: %v", action.ActionName, rule.ID, conversationID, err)
				actionsFailed++
				if firstErrorMsg == "" {
					firstErrorMsg = err.Error()
				}
				// Continue executing remaining actions (Chatwoot pattern)
			} else {
				actionsExecuted++
			}
		}

		// Log execution for audit trail
		logSvc := NewExecutionLogService(s.db)
		status := ExecutionStatusSuccess
		if actionsFailed > 0 && actionsExecuted > 0 {
			status = ExecutionStatusPartial
		} else if actionsFailed > 0 && actionsExecuted == 0 {
			status = ExecutionStatusFailed
		}
		if logErr := logSvc.LogRuleExecution(ctx, accountID, rule.ID, conversationID, status, actionsExecuted, actionsFailed, firstErrorMsg); logErr != nil {
			applogger.L().Warnf("failed to log automation execution for rule %d: %v", rule.ID, logErr)
		}
	}

	return nil
}

// loadConversation loads a conversation from the database.
func (s *AutomationRuleService) loadConversation(ctx context.Context, conversationID uint) (*ConversationForFilter, error) {
	var conv ConversationForFilter
	if err := s.db.DB().WithContext(ctx).
		Table("conversations").
		Where("id = ?", conversationID).
		First(&conv).Error; err != nil {
		return nil, err
	}
	return &conv, nil
}

// ConversationForFilter is a lightweight struct used for condition matching.
// It mirrors the conversation model fields needed by ConditionsFilterService.
type ConversationForFilter struct {
	ID            uint
	AccountID     uint
	InboxID       uint
	ContactID     uint
	AssigneeID    *uint
	Status        string
	Priority      string
	ChannelType   string
	LastMessageAt *int64
	Labels        []string `gorm:"type:text;serializer:json"` // populated from conversation_labels join if needed
}

// TableName overrides for GORM queries.
func (ConversationForFilter) TableName() string { return "conversations" }