// SPDX-License-Identifier: MPL-2.0

package cmssqlite

import (
	"context"
	"database/sql"
	"encoding/json"
	"gamertan.com/web/cms"
)

// PutRevision appends once. Unknown terms are rejected; retired terms remain
// usable when copying historical revisions. Editors decide whether to admit new
// retired-term assignments. Link targets are validated by the application: they
// can live in a different content/catalog store. A link grants no authority.
func PutRevision(ctx context.Context, tx *sql.Tx, scope string, ref cms.Reference, revision int64, a cms.Associations) error {
	if !cms.ValidID(scope) || revision < 1 || a.Validate(ref) != nil {
		return cms.ErrInvalid
	}
	for _, id := range a.Terms {
		var count int
		if err := tx.QueryRowContext(ctx, `SELECT COUNT(*) FROM gwf_cms_terms WHERE scope=? AND id=?`, scope, id).Scan(&count); err != nil {
			return err
		}
		if count != 1 {
			return cms.ErrNotFound
		}
	}
	b, err := json.Marshal(a)
	if err != nil {
		return err
	}
	if _, err = tx.ExecContext(ctx, `INSERT INTO gwf_cms_resources(scope,kind,id) VALUES(?,?,?) ON CONFLICT DO NOTHING`, scope, ref.Kind, ref.ID); err != nil {
		return err
	}
	result, err := tx.ExecContext(ctx, `INSERT INTO gwf_cms_associations(scope,kind,id,revision,document) VALUES(?,?,?,?,?) ON CONFLICT DO NOTHING`, scope, ref.Kind, ref.ID, revision, string(b))
	if err = oneRow(result, err); err != nil {
		return err
	}
	for _, id := range a.Terms {
		if _, err = tx.ExecContext(ctx, `INSERT INTO gwf_cms_memberships(scope,kind,id,revision,term_id) VALUES(?,?,?,?,?)`, scope, ref.Kind, ref.ID, revision, id); err != nil {
			return err
		}
	}
	for _, target := range a.Links {
		if _, err = tx.ExecContext(ctx, `INSERT INTO gwf_cms_links(scope,kind,id,revision,target_kind,target_id) VALUES(?,?,?,?,?,?)`, scope, ref.Kind, ref.ID, revision, target.Kind, target.ID); err != nil {
			return err
		}
	}
	return nil
}

// SetPublished selects an exact revision or zero to unpublish. Call inside the
// same transaction as the application's publication transition and audit. Draft
// saves do not call this function. Product availability is also checked by the
// consuming application; publication is not entitlement or payment authority.
func SetPublished(ctx context.Context, tx *sql.Tx, scope string, ref cms.Reference, revision int64) error {
	if !cms.ValidID(scope) || ref.Validate() != nil || revision < 0 {
		return cms.ErrInvalid
	}
	if revision > 0 {
		var count int
		if err := tx.QueryRowContext(ctx, `SELECT COUNT(*) FROM gwf_cms_associations WHERE scope=? AND kind=? AND id=? AND revision=?`, scope, ref.Kind, ref.ID, revision).Scan(&count); err != nil {
			return err
		}
		if count != 1 {
			return cms.ErrNotFound
		}
	}
	result, err := tx.ExecContext(ctx, `UPDATE gwf_cms_resources SET published_revision=? WHERE scope=? AND kind=? AND id=?`, revision, scope, ref.Kind, ref.ID)
	return oneRow(result, err)
}

func (r *Reader) Revision(ctx context.Context, ref cms.Reference, revision int64) (cms.Associations, error) {
	if ref.Validate() != nil || revision < 1 {
		return cms.Associations{}, cms.ErrInvalid
	}
	var raw string
	err := r.db.QueryRowContext(ctx, `SELECT document FROM gwf_cms_associations WHERE scope=? AND kind=? AND id=? AND revision=?`, r.scope, ref.Kind, ref.ID, revision).Scan(&raw)
	if err != nil {
		return cms.Associations{}, notFound(err)
	}
	var a cms.Associations
	if len(raw) > 16384 || json.Unmarshal([]byte(raw), &a) != nil || a.Validate(ref) != nil {
		return cms.Associations{}, cms.ErrInvalid
	}
	return a, nil
}
func (r *Reader) LatestRevision(ctx context.Context, ref cms.Reference) (int64, error) {
	if ref.Validate() != nil {
		return 0, cms.ErrInvalid
	}
	var revision sql.NullInt64
	err := r.db.QueryRowContext(ctx, `SELECT MAX(revision) FROM gwf_cms_associations WHERE scope=? AND kind=? AND id=?`, r.scope, ref.Kind, ref.ID).Scan(&revision)
	if err != nil {
		return 0, err
	}
	if !revision.Valid {
		return 0, cms.ErrNotFound
	}
	return revision.Int64, nil
}
func (r *Reader) PublishedRevision(ctx context.Context, ref cms.Reference) (int64, error) {
	if ref.Validate() != nil {
		return 0, cms.ErrInvalid
	}
	var revision int64
	err := r.db.QueryRowContext(ctx, `SELECT published_revision FROM gwf_cms_resources WHERE scope=? AND kind=? AND id=? AND published_revision>0`, r.scope, ref.Kind, ref.ID).Scan(&revision)
	return revision, notFound(err)
}

// Members returns published members of an active term and taxonomy. Pagination
// happens after publication filtering, with stable kind/ID cursors.
func (r *Reader) Members(ctx context.Context, termID string, after *cms.Reference, limit int) (cms.Page, error) {
	if !cms.ValidID(termID) {
		return cms.Page{}, cms.ErrInvalid
	}
	query := `SELECT DISTINCT r.kind,r.id,r.published_revision FROM gwf_cms_memberships m JOIN gwf_cms_resources r ON r.scope=m.scope AND r.kind=m.kind AND r.id=m.id AND r.published_revision=m.revision JOIN gwf_cms_terms t ON t.scope=m.scope AND t.id=m.term_id JOIN gwf_cms_taxonomies x ON x.scope=t.scope AND x.id=t.taxonomy_id WHERE m.scope=? AND m.term_id=? AND r.published_revision>0 AND t.active=1 AND x.active=1`
	return r.page(ctx, query, []any{r.scope, termID}, after, limit)
}

// Related returns both directions of explicit relationships between published
// revisions. Shared taxonomy membership alone does not assert a relationship.
func (r *Reader) Related(ctx context.Context, ref cms.Reference, after *cms.Reference, limit int) (cms.Page, error) {
	if ref.Validate() != nil {
		return cms.Page{}, cms.ErrInvalid
	}
	query := `WITH edges AS (
 SELECT l.target_kind AS kind,l.target_id AS id FROM gwf_cms_links l JOIN gwf_cms_resources s ON s.scope=l.scope AND s.kind=l.kind AND s.id=l.id AND s.published_revision=l.revision WHERE l.scope=? AND l.kind=? AND l.id=? AND s.published_revision>0
 UNION
 SELECT l.kind,l.id FROM gwf_cms_links l JOIN gwf_cms_resources s ON s.scope=l.scope AND s.kind=l.kind AND s.id=l.id AND s.published_revision=l.revision WHERE l.scope=? AND l.target_kind=? AND l.target_id=? AND s.published_revision>0
 ) SELECT r.kind,r.id,r.published_revision FROM edges e JOIN gwf_cms_resources r ON r.kind=e.kind AND r.id=e.id WHERE r.scope=? AND r.published_revision>0 AND NOT(r.kind=? AND r.id=?) AND EXISTS(SELECT 1 FROM gwf_cms_resources origin WHERE origin.scope=? AND origin.kind=? AND origin.id=? AND origin.published_revision>0)`
	return r.page(ctx, query, []any{r.scope, ref.Kind, ref.ID, r.scope, ref.Kind, ref.ID, r.scope, ref.Kind, ref.ID, r.scope, ref.Kind, ref.ID}, after, limit)
}

func (r *Reader) page(ctx context.Context, query string, args []any, after *cms.Reference, limit int) (cms.Page, error) {
	if limit < 1 || limit > 100 || (after != nil && after.Validate() != nil) {
		return cms.Page{}, cms.ErrInvalid
	}
	if after != nil {
		query += ` AND (r.kind>? OR (r.kind=? AND r.id>?))`
		args = append(args, after.Kind, after.Kind, after.ID)
	}
	query += ` ORDER BY r.kind,r.id LIMIT ?`
	args = append(args, limit+1)
	rows, err := r.db.QueryContext(ctx, query, args...)
	if err != nil {
		return cms.Page{}, err
	}
	defer rows.Close()
	p := cms.Page{Items: []cms.ResourceVersion{}}
	for rows.Next() {
		var v cms.ResourceVersion
		if err := rows.Scan(&v.Kind, &v.ID, &v.Revision); err != nil {
			return cms.Page{}, err
		}
		p.Items = append(p.Items, v)
	}
	if err := rows.Err(); err != nil {
		return cms.Page{}, err
	}
	if len(p.Items) > limit {
		p.Items = p.Items[:limit]
		ref := p.Items[limit-1].Reference
		p.Next = &ref
	}
	return p, nil
}