package Database

import (
	"database/sql"
	"os"
	"path/filepath"
	"time"

	_ "github.com/mattn/go-sqlite3"
	bolt "go.etcd.io/bbolt"

	"PackageManager/Variables"
)

var (
	DB   *sql.DB
	FsDB *bolt.DB
)

func InitConfigDir() error {
	var (
		e error
	)
	_, e = os.Stat(Variables.ConfigDir)
	if os.IsNotExist(e) {
		return os.MkdirAll(Variables.ConfigDir, 0644)
	}
	return e
}

func InitDatabaseFiles() error {
	var e error
	// Initialise sqlite3 database for package versioning
	DB, e = sql.Open(
		"sqlite3",
		filepath.Join(Variables.ConfigDir, Variables.DatabaseName),
	)
	if e != nil {
		return e
	}

	// Initialise bolt db for filesystem hashing
	FsDB, e = bolt.Open(
		filepath.Join(Variables.ConfigDir, Variables.FsHashDatabaseName),
		0600,
		&bolt.Options{
			Timeout: 5 * time.Second,
		})
	return e

}

func init() {
	var e error
	e = InitConfigDir()
	if e != nil {
		panic(e)
	}
	e = InitDatabaseFiles()
	if e != nil {
		panic(e)
	}
}

func InitBoltDB() error {
	var (
		tx *bolt.Tx
		e  error
	)

	tx, e = FsDB.Begin(true)
	if e != nil {
		return e
	}
	defer tx.Rollback()

	_, e = tx.CreateBucketIfNotExists(Variables.FsHashIndexBucket)
	if e != nil {
		return e
	}

	_, e = tx.CreateBucketIfNotExists(Variables.FsHashPicksBucket)
	if e != nil {
		return e
	}

	e = tx.Commit()

	return e
}

func InitSqlite3DB() error {
	var (
		stmt *sql.Stmt
		e    error
	)

	stmt, e = DB.Prepare(`
CREATE TABLE IF NOT EXISTS installed_packages (
	id INTEGER PRIMARY KEY AUTOINCREMENT,
	name VARCHAR(64) NOT NULL,
	version VARCHAR(64) NOT NULL,
	installed_at INTEGER NOT NULL
)
`)
	if e != nil {
		return e
	}

	_, e = stmt.Exec()
	if e != nil {
		return e
	}

	stmt, e = DB.Prepare(`
CREATE TABLE IF NOT EXISTS dependancy_linker (
	id INTEGER PRIMARY KEY AUTOINCREMENT,
	package_id INTEGER,
	dependancy_id INTEGER,
	FOREIGN KEY(package_id) REFERENCES installed_packages(id),
	FOREIGN KEY(dependancy_id) REFERENCES installed_packages(id)
)
`)
	if e != nil {
		return e
	}

	_, e = stmt.Exec()
	return e
}

func InitDB() error {
	var e error
	e = InitBoltDB()
	if e != nil {
		return e
	}

	return InitSqlite3DB()
}