package activity

import (
	"time"

	"verstak/internal/core/storage"
	"verstak/internal/core/util"
)

// Event types.
const (
	TypeNoteCreated  = "note_created"
	TypeNoteUpdated  = "note_updated"
	TypeFileAdded    = "file_added"
	TypeFileDeleted  = "file_deleted"
	TypeFileRenamed  = "file_renamed"
	TypeFileCopied   = "file_copied"
	TypeFileMoved    = "file_moved"
	TypeFolderAdded  = "folder_added"
	TypeFolderDeleted = "folder_deleted"
	TypeFolderRenamed = "folder_renamed"
	TypeNodeCreated  = "node_created"
	TypeNodeUpdated  = "node_updated"
)

// Event represents an activity event.
type Event struct {
	ID        string `json:"id"`
	NodeID    string `json:"node_id"`
	ParentID  string `json:"parent_id,omitempty"`
	EventType string `json:"event_type"`
	Title     string `json:"title"`
	Metadata  string `json:"metadata"`
	CreatedAt string `json:"created_at"`
}

// Service records and queries activity events.
type Service struct {
	db *storage.DB
}

func NewService(db *storage.DB) *Service {
	return &Service{db: db}
}

// Record inserts a new activity event.
func (s *Service) Record(nodeID, parentID, eventType, title, metadata string) error {
	id := util.UUID7()
	now := time.Now().UTC().Format(time.RFC3339)
	if metadata == "" {
		metadata = "{}"
	}
	if parentID != "" {
		_, err := s.db.Exec(
			`INSERT INTO activity_events(id,node_id,parent_id,event_type,title,metadata,created_at)
			 VALUES(?,?,?,?,?,?,?)`,
			id, nodeID, parentID, eventType, title, metadata, now)
		return err
	}
	_, err := s.db.Exec(
		`INSERT INTO activity_events(id,node_id,event_type,title,metadata,created_at)
		 VALUES(?,?,?,?,?,?)`,
		id, nodeID, eventType, title, metadata, now)
	return err
}

// todayBoundaries returns the current local day in UTC.
// TodayBoundaries returns the current local day in UTC as RFC3339 strings.
func TodayBoundaries() (string, string) {
	now := time.Now()
	y, m, d := now.Date()
	start := time.Date(y, m, d, 0, 0, 0, 0, now.Location())
	end := start.Add(24 * time.Hour)
	return start.UTC().Format(time.RFC3339), end.UTC().Format(time.RFC3339)
}

// ListTodayEvents returns all activity events from today.
func (s *Service) ListTodayEvents() ([]Event, error) {
	start, end := TodayBoundaries()
	rows, err := s.db.Query(
		`SELECT id,node_id,COALESCE(parent_id,''),event_type,title,metadata,created_at
		 FROM activity_events
		 WHERE created_at >= ? AND created_at < ?
		 ORDER BY created_at DESC`, start, end)
	if err != nil {
		return nil, err
	}
	defer rows.Close()
	var events []Event
	for rows.Next() {
		var e Event
		if err := rows.Scan(&e.ID, &e.NodeID, &e.ParentID, &e.EventType, &e.Title, &e.Metadata, &e.CreatedAt); err != nil {
			return nil, err
		}
		events = append(events, e)
	}
	return events, rows.Err()
}

// ListTodayEventsByParent returns activity events grouped by parent node.
func (s *Service) ListTodayEventsByParent() (map[string][]Event, error) {
	events, err := s.ListTodayEvents()
	if err != nil {
		return nil, err
	}
	grouped := make(map[string][]Event, 8)
	for _, e := range events {
		pid := e.ParentID
		if pid == "" {
			pid = e.NodeID
		}
		grouped[pid] = append(grouped[pid], e)
	}
	return grouped, nil
}