package database

import (
	"database/sql"
	"fmt"

	_ "modernc.org/sqlite"
)

// DB wraps the sqlite connection used by the whole application.
type DB struct {
	*sql.DB
}

const schema = `
CREATE TABLE IF NOT EXISTS servers (
	id             INTEGER PRIMARY KEY AUTOINCREMENT,
	name           TEXT NOT NULL UNIQUE,
	interface_name TEXT NOT NULL UNIQUE,
	listen_port    INTEGER NOT NULL,
	private_key    TEXT NOT NULL,
	public_key     TEXT NOT NULL,
	address_range  TEXT NOT NULL,
	dns            TEXT DEFAULT '',
	mtu            INTEGER DEFAULT 1420,
	enabled        INTEGER NOT NULL DEFAULT 1,
	created_at     DATETIME NOT NULL DEFAULT CURRENT_TIMESTAMP,
	updated_at     DATETIME NOT NULL DEFAULT CURRENT_TIMESTAMP
);

CREATE TABLE IF NOT EXISTS peers (
	id                   INTEGER PRIMARY KEY AUTOINCREMENT,
	server_id            INTEGER NOT NULL REFERENCES servers(id) ON DELETE CASCADE,
	name                 TEXT NOT NULL,
	email                TEXT DEFAULT '',
	public_key           TEXT NOT NULL,
	private_key          TEXT DEFAULT '',
	preshared_key        TEXT DEFAULT '',
	allowed_ips          TEXT NOT NULL,
	endpoint             TEXT DEFAULT '',
	persistent_keepalive INTEGER DEFAULT 25,
	enabled              INTEGER NOT NULL DEFAULT 1,
	expires_at           DATETIME,
	created_at           DATETIME NOT NULL DEFAULT CURRENT_TIMESTAMP,
	updated_at           DATETIME NOT NULL DEFAULT CURRENT_TIMESTAMP
);

CREATE TABLE IF NOT EXISTS audit_log (
	id         INTEGER PRIMARY KEY AUTOINCREMENT,
	actor      TEXT NOT NULL,
	action     TEXT NOT NULL,
	target     TEXT NOT NULL,
	detail     TEXT DEFAULT '',
	created_at DATETIME NOT NULL DEFAULT CURRENT_TIMESTAMP
);

CREATE TABLE IF NOT EXISTS users (
	id            INTEGER PRIMARY KEY AUTOINCREMENT,
	username      TEXT NOT NULL UNIQUE,
	password_hash TEXT NOT NULL,
	created_at    DATETIME NOT NULL DEFAULT CURRENT_TIMESTAMP
);

CREATE INDEX IF NOT EXISTS idx_peers_server_id ON peers(server_id);
`

// Open opens (creating if needed) the sqlite database at path and applies schema.
func Open(path string) (*DB, error) {
	sqlDB, err := sql.Open("sqlite", path+"?_pragma=foreign_keys(1)")
	if err != nil {
		return nil, fmt.Errorf("open sqlite: %w", err)
	}
	if _, err := sqlDB.Exec(schema); err != nil {
		sqlDB.Close()
		return nil, fmt.Errorf("apply schema: %w", err)
	}
	return &DB{sqlDB}, nil
}

// LogAudit records an entry in the audit log.
func (db *DB) LogAudit(actor, action, target, detail string) error {
	_, err := db.Exec(`INSERT INTO audit_log (actor, action, target, detail) VALUES (?, ?, ?, ?)`,
		actor, action, target, detail)
	return err
}