ax/service/node_service_impl.go

package service

import (
	"axolotl/models"
	"axolotl/store"
	"fmt"
	"maps"
	"regexp"
	"slices"
	"time"
)

type nodeServiceImpl struct {
	store  store.Store
	userID string
}

var mentionRegex = regexp.MustCompile(`@([a-z0-9_]+)`)

func mentions(t string) []string {
	seen := make(map[string]bool)
	for _, m := range mentionRegex.FindAllStringSubmatch(t, -1) {
		seen[m[1]] = true
	}
	return slices.Collect(maps.Keys(seen))
}

// --- Query ---

func (s *nodeServiceImpl) GetByID(id string) (*models.Node, error) {
	return s.store.GetNode(id)
}

func (s *nodeServiceImpl) List(filter ListFilter) ([]*models.Node, error) {
	// Build tag prefixes from both semantic fields and raw tags.
	tagPrefixes := append([]string{}, filter.Tags...)
	if filter.Status != "" {
		tagPrefixes = append(tagPrefixes, "_status::"+filter.Status)
	}
	if filter.Priority != "" {
		tagPrefixes = append(tagPrefixes, "_prio::"+filter.Priority)
	}
	if filter.Type != "" {
		tagPrefixes = append(tagPrefixes, "_type::"+filter.Type)
	}

	// Build rel filters, resolving names to node IDs (read-only, no auto-creation).
	type relEntry struct {
		relType models.RelType
		name    string
	}
	namedRels := []relEntry{
		{models.RelAssignee, filter.Assignee},
		{models.RelInNamespace, filter.Namespace},
		{models.RelMentions, filter.Mention},
	}
	var relFilters []*models.Rel
	for _, e := range namedRels {
		if e.name == "" {
			continue
		}
		id, ok := s.lookupRelTarget(e.relType, e.name)
		if !ok {
			return nil, nil // named target doesn't exist; no nodes can match
		}
		relFilters = append(relFilters, &models.Rel{Type: e.relType, Target: id})
	}
	for _, ri := range filter.Rels {
		id, ok := s.lookupRelTarget(ri.Type, ri.Target)
		if !ok {
			return nil, nil
		}
		relFilters = append(relFilters, &models.Rel{Type: ri.Type, Target: id})
	}

	return s.store.FindNodes(tagPrefixes, relFilters)
}

// --- Lifecycle ---

func (s *nodeServiceImpl) Add(input AddInput) (*models.Node, error) {
	// Apply defaults.
	nodeType := input.Type
	if nodeType == "" {
		nodeType = "issue"
	}
	status := input.Status
	if status == "" && nodeType == "issue" {
		status = "open"
	}

	// Build initial tag set from semantic fields.
	tags := []string{"_type::" + nodeType}
	if status != "" {
		tags = append(tags, "_status::"+status)
	}
	if input.Priority != "" {
		tags = append(tags, "_prio::"+input.Priority)
	}
	tags = append(tags, input.Tags...)

	// Build initial relation map from semantic fields.
	rels := make(map[models.RelType][]string)
	if input.Namespace != "" {
		rels[models.RelInNamespace] = []string{input.Namespace}
	} else {
		rels[models.RelInNamespace] = []string{s.userID} // default: creator's namespace
	}
	if input.Assignee != "" {
		rels[models.RelAssignee] = []string{input.Assignee}
	}
	for _, ri := range input.Rels {
		rels[ri.Type] = append(rels[ri.Type], ri.Target)
	}

	id, err := s.store.GenerateID()
	if err != nil {
		return nil, err
	}

	err = s.store.Transaction(func(st store.Store) error {
		now := time.Now().UTC().Format(time.RFC3339)
		if err := st.AddNode(id, input.Title, input.Content, input.DueDate, now, now); err != nil {
			return err
		}

		for _, m := range mentions(input.Title + " " + input.Content) {
			userID, err := s.resolveUserRef(st, m)
			if err != nil {
				return err
			}
			if err := st.AddEdge(id, userID, models.RelMentions); err != nil {
				return err
			}
		}

		for _, t := range tags {
			if err := st.AddTag(id, t); err != nil {
				return err
			}
		}

		hasCreated := false
		for rt, tgts := range rels {
			for _, tgt := range tgts {
				if rt == models.RelCreated {
					hasCreated = true
				}
				resolved, err := s.resolveRelTarget(st, RelInput{Type: rt, Target: tgt})
				if err != nil {
					return err
				}
				if err := st.AddEdge(id, resolved, rt); err != nil {
					return err
				}
			}
		}

		if !hasCreated {
			userID, err := s.resolveUserRef(st, s.userID)
			if err != nil {
				return err
			}
			if err := st.AddEdge(id, userID, models.RelCreated); err != nil {
				return err
			}
		}

		return nil
	})
	if err != nil {
		return nil, err
	}
	return s.store.GetNode(id)
}

func (s *nodeServiceImpl) Update(id string, input UpdateInput) (*models.Node, error) {
	// Enforce blocking constraint before allowing status=done.
	if input.Status != nil && *input.Status == "done" {
		if err := s.checkBlockers(id); err != nil {
			return nil, err
		}
	}

	err := s.store.Transaction(func(st store.Store) error {
		current, err := st.GetNode(id)
		if err != nil {
			return err
		}

		// Determine final scalar values.
		title, content, dueDate := current.Title, current.Content, current.DueDate
		if input.Title != nil {
			title = *input.Title
		}
		if input.Content != nil {
			content = *input.Content
		}
		if input.DueDate != nil {
			dueDate = *input.DueDate
		}

		now := time.Now().UTC().Format(time.RFC3339)
		if err := st.UpdateNode(id, title, content, dueDate, now); err != nil {
			return err
		}

		// Compute new tag set using the model's AddTag/RemoveTag to preserve
		// property-prefix replacement semantics.
		tmp := models.NewNode()
		for _, t := range current.Tags() {
			tmp.AddTag(t)
		}
		if input.Type != nil {
			tmp.AddTag("_type::" + *input.Type)
		}
		if input.Status != nil {
			tmp.AddTag("_status::" + *input.Status)
		}
		if input.Priority != nil {
			tmp.AddTag("_prio::" + *input.Priority)
		}
		for _, t := range input.AddTags {
			tmp.AddTag(t)
		}
		for _, t := range input.RemoveTags {
			tmp.RemoveTag(t) //nolint: the error is only for _type:: removal, which is intentionally prevented
		}

		// Sync tags to store.
		currentTags, newTags := current.Tags(), tmp.Tags()
		for _, t := range currentTags {
			if !slices.Contains(newTags, t) {
				if err := st.RemoveTag(id, t); err != nil {
					return err
				}
			}
		}
		for _, t := range newTags {
			if !slices.Contains(currentTags, t) {
				if err := st.AddTag(id, t); err != nil {
					return err
				}
			}
		}

		// Sync mention edges when title or content changed.
		if input.Title != nil || input.Content != nil {
			if err := s.syncMentions(st, id, current, title, content); err != nil {
				return err
			}
		}

		// Build relation additions, including structured fields.
		var addRels []RelInput
		if input.Namespace != nil {
			addRels = append(addRels, RelInput{Type: models.RelInNamespace, Target: *input.Namespace})
		}
		if input.Assignee != nil {
			addRels = append(addRels, RelInput{Type: models.RelAssignee, Target: *input.Assignee})
		}
		addRels = append(addRels, input.AddRels...)

		currentRels := current.Relations()
		for _, ri := range addRels {
			resolved, err := s.resolveRelTarget(st, ri)
			if err != nil {
				return err
			}
			// Single-value relations replace the previous target.
			if ri.Type == models.RelAssignee || ri.Type == models.RelInNamespace {
				for _, oldTgt := range currentRels[string(ri.Type)] {
					if err := st.RemoveEdge(id, oldTgt, ri.Type); err != nil {
						return err
					}
				}
			}
			if err := st.AddEdge(id, resolved, ri.Type); err != nil {
				return err
			}
		}

		for _, ri := range input.RemoveRels {
			resolved, err := s.resolveRelTarget(st, ri)
			if err != nil {
				return err
			}
			if err := st.RemoveEdge(id, resolved, ri.Type); err != nil {
				return err
			}
		}

		return nil
	})
	if err != nil {
		return nil, err
	}
	return s.store.GetNode(id)
}

func (s *nodeServiceImpl) Delete(id string) error {
	return s.store.DeleteNode(id)
}

// --- User management ---

func (s *nodeServiceImpl) AddUser(name string) (*models.Node, error) {
	var id string
	err := s.store.Transaction(func(st store.Store) error {
		var err error
		id, err = s.ensureUser(st, name)
		return err
	})
	if err != nil {
		return nil, err
	}
	return s.store.GetNode(id)
}

func (s *nodeServiceImpl) ListUsers() ([]*models.Node, error) {
	return s.store.FindNodes([]string{"_type::user"}, nil)
}

// --- Internal helpers ---

func (s *nodeServiceImpl) checkBlockers(id string) error {
	// Find all nodes that declare a blocks → id relation (i.e., open blockers).
	blockers, err := s.store.FindNodes(nil, []*models.Rel{{Type: models.RelBlocks, Target: id}})
	if err != nil {
		return err
	}
	var blocking []string
	for _, b := range blockers {
		if b.GetProperty("status") == "open" {
			blocking = append(blocking, b.ID)
		}
	}
	if len(blocking) > 0 {
		return fmt.Errorf("cannot close: blocked by %v", blocking)
	}
	return nil
}

func (s *nodeServiceImpl) syncMentions(st store.Store, id string, current *models.Node, newTitle, newContent string) error {
	existingMentionIDs := make(map[string]bool)
	for _, uid := range current.Relations()[string(models.RelMentions)] {
		existingMentionIDs[uid] = true
	}
	mentionedUserIDs := make(map[string]bool)
	for _, m := range mentions(newTitle + " " + newContent) {
		userID, err := s.resolveUserRef(st, m)
		if err != nil {
			return err
		}
		mentionedUserIDs[userID] = true
		if !existingMentionIDs[userID] {
			if err := st.AddEdge(id, userID, models.RelMentions); err != nil {
				return err
			}
		}
	}
	for uid := range existingMentionIDs {
		if !mentionedUserIDs[uid] {
			if err := st.RemoveEdge(id, uid, models.RelMentions); err != nil {
				return err
			}
		}
	}
	return nil
}

// resolveRelTarget resolves a RelInput target to a node ID, auto-creating users
// and namespaces as needed. Use only inside a transaction.
func (s *nodeServiceImpl) resolveRelTarget(st store.Store, ri RelInput) (string, error) {
	switch ri.Type {
	case models.RelAssignee, models.RelCreated, models.RelMentions:
		return s.resolveUserRef(st, ri.Target)
	case models.RelInNamespace:
		return s.resolveNamespaceRef(st, ri.Target)
	default:
		return ri.Target, nil // blocks/subtask/related expect raw node IDs
	}
}

// lookupRelTarget resolves a filter target to a node ID without creating anything.
// Returns ("", false) when the target doesn't exist.
func (s *nodeServiceImpl) lookupRelTarget(relType models.RelType, target string) (string, bool) {
	if exists, _ := s.store.NodeExists(target); exists {
		return target, true
	}
	var nodeType string
	switch relType {
	case models.RelAssignee, models.RelCreated, models.RelMentions:
		nodeType = "user"
	case models.RelInNamespace:
		nodeType = "namespace"
	default:
		return target, true
	}
	id, err := s.resolveIDByNameAndType(s.store, target, nodeType)
	if err != nil || id == "" {
		return "", false
	}
	return id, true
}

// resolveIDByNameAndType finds a node by title and _type tag without creating it.
func (s *nodeServiceImpl) resolveIDByNameAndType(st store.Store, title, nodeType string) (string, error) {
	nodes, err := st.FindNodes([]string{"_type::" + nodeType}, nil)
	if err != nil {
		return "", err
	}
	for _, n := range nodes {
		if n.Title == title {
			return n.ID, nil
		}
	}
	return "", nil
}

func (s *nodeServiceImpl) resolveUserRef(st store.Store, ref string) (string, error) {
	if exists, _ := st.NodeExists(ref); exists {
		return ref, nil
	}
	return s.ensureUser(st, ref)
}

func (s *nodeServiceImpl) ensureUser(st store.Store, username string) (string, error) {
	userID, err := s.resolveIDByNameAndType(st, username, "user")
	if err != nil {
		return "", err
	}
	if userID != "" {
		return userID, nil
	}
	id, err := st.GenerateID()
	if err != nil {
		return "", err
	}
	now := time.Now().UTC().Format(time.RFC3339)
	if err := st.AddNode(id, username, "", "", now, now); err != nil {
		return "", err
	}
	if err := st.AddTag(id, "_type::user"); err != nil {
		return "", err
	}
	return id, nil
}

func (s *nodeServiceImpl) resolveNamespaceRef(st store.Store, ref string) (string, error) {
	if exists, _ := st.NodeExists(ref); exists {
		return ref, nil
	}
	return s.ensureNamespace(st, ref)
}

func (s *nodeServiceImpl) ensureNamespace(st store.Store, name string) (string, error) {
	nsID, err := s.resolveIDByNameAndType(st, name, "namespace")
	if err != nil {
		return "", err
	}
	if nsID != "" {
		return nsID, nil
	}
	id, err := st.GenerateID()
	if err != nil {
		return "", err
	}
	now := time.Now().UTC().Format(time.RFC3339)
	if err := st.AddNode(id, name, "", "", now, now); err != nil {
		return "", err
	}
	if err := st.AddTag(id, "_type::namespace"); err != nil {
		return "", err
	}
	if err := st.AddEdge(id, id, models.RelInNamespace); err != nil {
		return "", err
	}
	userID, err := s.resolveUserRef(st, s.userID)
	if err != nil {
		return "", err
	}
	if err := st.AddEdge(id, userID, models.RelCreated); err != nil {
		return "", err
	}
	return id, nil
}