import React, { useState, useEffect, useContext } from "react";
import { Box, Text } from "theme-ui";

import Banner from "../components/Banner";

import { getDatabase } from "../database";

const DatabaseContext = React.createContext();

export function DatabaseProvider({ children }) {
  const [database, setDatabase] = useState();
  const [databaseStatus, setDatabaseStatus] = useState("loading");
  const [databaseError, setDatabaseError] = useState();

  useEffect(() => {
    // Create a test database and open it to see if indexedDB is enabled
    let testDBRequest = window.indexedDB.open("__test");
    testDBRequest.onsuccess = async function () {
      testDBRequest.result.close();
      let db = getDatabase({ autoOpen: false });
      setDatabase(db);
      db.on("ready", () => {
        setDatabaseStatus("loaded");
      });
      await db.open();
      window.indexedDB.deleteDatabase("__test");
    };
    // If indexedb disabled create an in memory database
    testDBRequest.onerror = async function () {
      console.warn("Database is disabled, no state will be saved");
      const indexedDB = await import("fake-indexeddb");
      const IDBKeyRange = await import("fake-indexeddb/lib/FDBKeyRange");
      let db = getDatabase({ indexedDB, IDBKeyRange, autoOpen: false });
      setDatabase(db);
      db.on("ready", () => {
        setDatabaseStatus("disabled");
      });
      await db.open();
      window.indexedDB.deleteDatabase("__test");
    };

    function handleDatabaseError(event) {
      if (event.reason.name === "QuotaExceededError") {
        event.preventDefault();
        setDatabaseError({
          name: event.reason.name,
          message: "Storage Quota Exceeded Please Clear Space and Try Again.",
        });
      }
    }
    window.addEventListener("unhandledrejection", handleDatabaseError);

    return () => {
      window.removeEventListener("unhandledrejection", handleDatabaseError);
    };
  }, []);

  const value = {
    database,
    databaseStatus,
    databaseError,
  };
  return (
    <DatabaseContext.Provider value={value}>
      <>
        {children}
        <Banner
          isOpen={!!databaseError}
          onRequestClose={() => setDatabaseError()}
        >
          <Box p={1}>
            <Text as="p" variant="body2">
              {databaseError && databaseError.message}
            </Text>
          </Box>
        </Banner>
      </>
    </DatabaseContext.Provider>
  );
}

export function useDatabase() {
  const context = useContext(DatabaseContext);
  if (context === undefined) {
    throw new Error("useDatabase must be used within a DatabaseProvider");
  }
  return context;
}

export default DatabaseContext;