package sqlite

import (
	"database/sql"

	_ "github.com/mattn/go-sqlite3"
	"github.com/mickael-menu/zk/util/errors"
)

// DB holds the connections to a SQLite database.
type DB struct {
	db *sql.DB
}

// Open creates a new DB instance for the SQLite database at the given path.
func Open(path string) (*DB, error) {
	return open("file:" + path)
}

// OpenInMemory creates a new in-memory DB instance.
func OpenInMemory() (*DB, error) {
	return open(":memory:")
}

func open(uri string) (*DB, error) {
	db, err := sql.Open("sqlite3", uri)
	if err != nil {
		return nil, errors.Wrap(err, "failed to open the database")
	}
	return &DB{db}, nil
}

// Close terminates the connections to the SQLite database.
func (db *DB) Close() error {
	err := db.db.Close()
	return errors.Wrap(err, "failed to close the database")
}

// Migrate upgrades the SQL schema of the database.
func (db *DB) Migrate() error {
	err := db.WithTransaction(func(tx Transaction) error {
		var version int
		err := tx.QueryRow("PRAGMA user_version").Scan(&version)
		if err != nil {
			return err
		}

		if version == 0 {
			err = tx.ExecStmts([]string{
				`CREATE TABLE IF NOT EXISTS notes (
					id INTEGER PRIMARY KEY AUTOINCREMENT NOT NULL,
					path TEXT NOT NULL,
					title TEXT DEFAULT('') NOT NULL,
					lead TEXT DEFAULT('') NOT NULL,
					body TEXT DEFAULT('') NOT NULL,
					raw_content TEXT DEFAULT('') NOT NULL,
					word_count INTEGER DEFAULT(0) NOT NULL,
					checksum TEXT NOT NULL,
					created DATETIME DEFAULT(CURRENT_TIMESTAMP) NOT NULL,
					modified DATETIME DEFAULT(CURRENT_TIMESTAMP) NOT NULL,
					UNIQUE(path)
				)`,
				`CREATE INDEX IF NOT EXISTS index_notes_checksum ON notes (checksum)`,
				`CREATE INDEX IF NOT EXISTS index_notes_path ON notes (path)`,
				`CREATE VIRTUAL TABLE IF NOT EXISTS notes_fts USING fts5(
					path, title, body,
					content = notes,
					content_rowid = id,
					tokenize = "porter unicode61 remove_diacritics 1 tokenchars '''&/'"
				)`,
				// Triggers to keep the FTS index up to date.
				`CREATE TRIGGER IF NOT EXISTS trigger_notes_ai AFTER INSERT ON notes BEGIN
					INSERT INTO notes_fts(rowid, path, title, body) VALUES (new.id, new.path, new.title, new.body);
				END`,
				`CREATE TRIGGER IF NOT EXISTS trigger_notes_ad AFTER DELETE ON notes BEGIN
					INSERT INTO notes_fts(notes_fts, rowid, path, title, body) VALUES('delete', old.id, old.path, old.title, old.body);
				END`,
				`CREATE TRIGGER IF NOT EXISTS trigger_notes_au AFTER UPDATE ON notes BEGIN
					INSERT INTO notes_fts(notes_fts, rowid, path, title, body) VALUES('delete', old.id, old.path, old.title, old.body);
					INSERT INTO notes_fts(rowid, path, title, body) VALUES (new.id, new.path, new.title, new.body);
				END`,
				`PRAGMA user_version = 1`,
			})

			if err != nil {
				return err
			}
		}

		return nil
	})

	return errors.Wrap(err, "database migration failed")
}