package db

import (
	"database/sql"

	_ "modernc.org/sqlite"
)

type SearchDB struct {
	db *sql.DB
}

type SearchPage struct {
	Path    string
	Title   string
	Content string
}

type SearchResult struct {
	Path    string
	Title   string
	Snippet string
}

func OpenSearch(path string) (*SearchDB, error) {
	db, err := sql.Open("sqlite3", path)
	if err != nil {
		return nil, err
	}
	_, err = db.Exec(`
		CREATE TABLE IF NOT EXISTS indexed_pages (
			path       TEXT NOT NULL PRIMARY KEY,
			updated_at DATETIME DEFAULT CURRENT_TIMESTAMP
		);
		CREATE VIRTUAL TABLE IF NOT EXISTS pages_fts USING fts5(
			path      UNINDEXED,
			title,
			content,
			tokenize = 'porter unicode61'
		);
	`)
	if err != nil {
		return nil, err
	}
	return &SearchDB{db: db}, nil
}

func (s *SearchDB) Close() error { return s.db.Close() }

func (s *SearchDB) IndexPage(p SearchPage) error {
	tx, err := s.db.Begin()
	if err != nil {
		return err
	}
	defer tx.Rollback()

	if _, err = tx.Exec(`DELETE FROM pages_fts WHERE path = ?`, p.Path); err != nil {
		return err
	}
	if _, err = tx.Exec(
		`INSERT INTO pages_fts (path, title, content) VALUES (?, ?, ?)`,
		p.Path, p.Title, p.Content,
	); err != nil {
		return err
	}
	if _, err = tx.Exec(`
		INSERT INTO indexed_pages (path, updated_at) VALUES (?, CURRENT_TIMESTAMP)
		ON CONFLICT(path) DO UPDATE SET updated_at = CURRENT_TIMESTAMP
	`, p.Path); err != nil {
		return err
	}
	return tx.Commit()
}

func (s *SearchDB) DeletePage(path string) error {
	tx, err := s.db.Begin()
	if err != nil {
		return err
	}
	defer tx.Rollback()
	if _, err = tx.Exec(`DELETE FROM pages_fts WHERE path = ?`, path); err != nil {
		return err
	}
	if _, err = tx.Exec(`DELETE FROM indexed_pages WHERE path = ?`, path); err != nil {
		return err
	}
	return tx.Commit()
}

// Search runs a full-text query and returns up to 20 results with snippets.
func (s *SearchDB) Search(query string) ([]SearchResult, error) {
	rows, err := s.db.Query(`
		SELECT path, title,
			snippet(pages_fts, 2, '<mark>', '</mark>', '...', 20)
		FROM pages_fts
		WHERE pages_fts MATCH ?
		ORDER BY rank
		LIMIT 20
	`, query)
	if err != nil {
		return nil, err
	}
	defer rows.Close()
	var results []SearchResult
	for rows.Next() {
		var r SearchResult
		if err := rows.Scan(&r.Path, &r.Title, &r.Snippet); err != nil {
			return nil, err
		}
		results = append(results, r)
	}
	return results, rows.Err()
}