import {dbProvider} from "./db-provider";
import {value as createSql} from "./db-session-create_sql";
import {value as deleteSql} from "./db-session-delete_sql";
import {value as expireSql} from "./db-session-expire_sql";
import {value as updateSql} from "./db-session-update_sql";
import {value as verifySql} from "./db-session-verify_sql";
import debugCtor = require("debug");

const debug = debugCtor("db:session");

export function dbSessionCtor(dbProvider) {
  return {
    api: {
      /* return {sessionId:} */
      async create(): Promise<{ sessionId: string, data: object }> {
        const dbs = await dbProvider();
        const result = await dbs.write.one(createSql);
        debug(`create result: ${JSON.stringify(result)}`);
        if (!result || !result.id) {
          throw Error("could not create a new session.");
        }
        return {sessionId: result.id, data: result.data};
      },

      /* return {sessionId: userId:, data:} or null */
      async verify(sessionId: string): Promise<{ sessionId: string, data: object, userId: string } | null> {
        const dbs = await dbProvider();
        const result: { user_id: string, data: object } = await dbs.read.oneOrNone(
          verifySql,
          {
            sessionId,
          },
        );
        debug(`verify result: ${JSON.stringify(result)}`);
        if (result) {
          return {sessionId, userId: result.user_id, data: result.data};
        }
        return null;
      },

      /* data is persisted and expiry is extended by expiryInterval milliseconds */
      async update(sessionInfo: { sessionId: string, data: object, userId: string }, expiryInterval: number): Promise<void> {
        const dbs = await dbProvider();
        const result = await dbs.write.result(
          updateSql,
          {
            sessionId: sessionInfo.sessionId,
            userId: sessionInfo.userId,
            data: sessionInfo.data,
            expiryInterval,
          },
        );
        debug(`update result: ${JSON.stringify(result)}`);
      },

      /* expire old sessions */
      async expire(): Promise<void> {
        const dbs = await dbProvider();
        const result = await dbs.delete.result(expireSql);
        debug(`expire result: ${JSON.stringify(result)}`);
      },

      async delete(sessionId: string): Promise<void> {
        const dbs = await dbProvider();
        const result = await dbs.delete.result(deleteSql, {sessionId});
        debug(`delete result: ${JSON.stringify(result)}`);
      },
    },
    dbProvider,
  };
}

export const dbSession = dbSessionCtor(dbProvider).api;