package store

import (
	"context"
	"time"
)

// Section is an announcement shown on every page and post of a blog.
type Section struct {
	ID        int64
	BlogID    int64
	Title     string
	BodyMD    string
	BodyHTML  string
	Placement string // above | below | sidebar
	Style     string // plain | note | warning
	Enabled   bool
	SortOrder int
	CreatedAt time.Time
	UpdatedAt time.Time
}

const sectionCols = `id, blog_id, title, body_md, body_html, placement, style, enabled, sort_order, created_at, updated_at`

func scanSection(row interface{ Scan(...any) error }) (*Section, error) {
	var s Section
	err := row.Scan(&s.ID, &s.BlogID, &s.Title, &s.BodyMD, &s.BodyHTML, &s.Placement, &s.Style, &s.Enabled, &s.SortOrder, &s.CreatedAt, &s.UpdatedAt)
	if err != nil {
		return nil, wrap(err)
	}
	return &s, nil
}

func (s *Store) collectSections(ctx context.Context, q string, args ...any) ([]Section, error) {
	rows, err := s.db.Query(ctx, q, args...)
	if err != nil {
		return nil, err
	}
	defer rows.Close()
	var out []Section
	for rows.Next() {
		sec, err := scanSection(rows)
		if err != nil {
			return nil, err
		}
		out = append(out, *sec)
	}
	return out, rows.Err()
}

func (s *Store) ListSections(ctx context.Context, blogID int64) ([]Section, error) {
	return s.collectSections(ctx, `SELECT `+sectionCols+` FROM sections WHERE blog_id=$1 ORDER BY sort_order, id`, blogID)
}

// EnabledSections is what the public blog renders.
func (s *Store) EnabledSections(ctx context.Context, blogID int64) ([]Section, error) {
	return s.collectSections(ctx, `SELECT `+sectionCols+` FROM sections WHERE blog_id=$1 AND enabled ORDER BY sort_order, id`, blogID)
}

func (s *Store) SectionByID(ctx context.Context, blogID, id int64) (*Section, error) {
	return scanSection(s.db.QueryRow(ctx, `SELECT `+sectionCols+` FROM sections WHERE blog_id=$1 AND id=$2`, blogID, id))
}

func (s *Store) CreateSection(ctx context.Context, sec *Section) (*Section, error) {
	return scanSection(s.db.QueryRow(ctx, `INSERT INTO sections (blog_id, title, body_md, body_html, placement, style, enabled, sort_order)
		VALUES ($1,$2,$3,$4,$5,$6,$7,(SELECT coalesce(max(sort_order),-1)+1 FROM sections WHERE blog_id=$1)) RETURNING `+sectionCols,
		sec.BlogID, sec.Title, sec.BodyMD, sec.BodyHTML, sec.Placement, sec.Style, sec.Enabled))
}

func (s *Store) UpdateSection(ctx context.Context, sec *Section) error {
	_, err := s.db.Exec(ctx, `UPDATE sections SET title=$3, body_md=$4, body_html=$5, placement=$6, style=$7, enabled=$8, updated_at=now() WHERE blog_id=$1 AND id=$2`,
		sec.BlogID, sec.ID, sec.Title, sec.BodyMD, sec.BodyHTML, sec.Placement, sec.Style, sec.Enabled)
	return wrap(err)
}

func (s *Store) SetSectionEnabled(ctx context.Context, blogID, id int64, on bool) error {
	_, err := s.db.Exec(ctx, `UPDATE sections SET enabled=$3, updated_at=now() WHERE blog_id=$1 AND id=$2`, blogID, id, on)
	return err
}

func (s *Store) DeleteSection(ctx context.Context, blogID, id int64) error {
	_, err := s.db.Exec(ctx, `DELETE FROM sections WHERE blog_id=$1 AND id=$2`, blogID, id)
	return err
}

// MoveSection swaps sort_order with the neighbouring section (dir = -1 up, +1 down).
func (s *Store) MoveSection(ctx context.Context, blogID, id int64, dir int) error {
	secs, err := s.ListSections(ctx, blogID)
	if err != nil {
		return err
	}
	idx := -1
	for i := range secs {
		if secs[i].ID == id {
			idx = i
		}
	}
	j := idx + dir
	if idx < 0 || j < 0 || j >= len(secs) {
		return nil
	}
	secs[idx], secs[j] = secs[j], secs[idx]
	tx, err := s.db.Begin(ctx)
	if err != nil {
		return err
	}
	defer tx.Rollback(ctx)
	for i, sec := range secs { // renumber everything; keeps orders dense
		if _, err := tx.Exec(ctx, `UPDATE sections SET sort_order=$3 WHERE blog_id=$1 AND id=$2`, blogID, sec.ID, i); err != nil {
			return err
		}
	}
	return tx.Commit(ctx)
}