Paginate search results.

closes #16

frontend/package-lock.json

@@ -1383,6 +1383,18 @@
         "@babel/runtime": "^7.4.4"
       }
     },
+    "@material-ui/lab": {
+      "version": "4.0.0-alpha.56",
+      "resolved": "https://registry.npmjs.org/@material-ui/lab/-/lab-4.0.0-alpha.56.tgz",
+      "integrity": "sha512-xPlkK+z/6y/24ka4gVJgwPfoCF4RCh8dXb1BNE7MtF9bXEBLN/lBxNTK8VAa0qm3V2oinA6xtUIdcRh0aeRtVw==",
+      "requires": {
+        "@babel/runtime": "^7.4.4",
+        "@material-ui/utils": "^4.10.2",
+        "clsx": "^1.0.4",
+        "prop-types": "^15.7.2",
+        "react-is": "^16.8.0"
+      }
+    },
     "@material-ui/styles": {
       "version": "4.10.0",
       "resolved": "https://registry.npmjs.org/@material-ui/styles/-/styles-4.10.0.tgz",

frontend/package.json

@@ -6,6 +6,7 @@
   "dependencies": {
     "@material-ui/core": "^4.10.2",
     "@material-ui/icons": "^4.9.1",
+    "@material-ui/lab": "^4.0.0-alpha.56",
     "@testing-library/jest-dom": "^4.2.4",
     "@testing-library/react": "^9.5.0",
     "@testing-library/user-event": "^7.2.1",

frontend/src/SearchPage.js

@@ -5,8 +5,13 @@ import Paper from '@material-ui/core/Paper';
 import Typography from '@material-ui/core/Typography';
 import TextField from '@material-ui/core/TextField';
 import Container from '@material-ui/core/Container';
+import Pagination from '@material-ui/lab/Pagination';
 
 import { useSearch } from './utils/useSearch';
+import {
+  useLocationSearch,
+  useLocationSearchState
+} from './utils/routing';
 import { SearchHit } from './SearchHit';
 
 
@@ -22,11 +27,15 @@ const classes = makeStyles((theme) => ({
   },
 }));
 
-
 export const SearchPage = () => {
-  const [titleQuery, setTitleQuery] = useState("");
+  const pageSize = 20;
+  const [query, setQuery] = useLocationSearchState('query', '');
+  const [pageNumber, setPageNumber] = useLocationSearchState('page', 1, parseInt);
+  const [_, setLocationSearch] = useLocationSearch();
 
-  const [results, resultsAreLoading] =  useSearch(titleQuery);
+
+  const [results, numberOfHits, error, resultsAreLoading] =  useSearch(query, pageSize, pageNumber);
+  const totalPages = Math.ceil(numberOfHits/pageSize);
 
   let resultsDisplay="No rule found...";
   if (resultsAreLoading) {
@@ -36,6 +45,14 @@ export const SearchPage = () => {
     resultsDisplay = results.map(result => <SearchHit key={result.id} data={result}/>)
   }
 
+  function handleQueryUpdate(event) {
+    if (pageNumber > 1) {
+      setLocationSearch({query: event.target.value, page: 1});
+    } else {
+      setQuery(event.target.value, {push: false});
+    }
+  }
+ 
   return (
     <div>
     <Paper className={classes.languagesBar}>
@@ -52,15 +69,21 @@ export const SearchPage = () => {
             shrink: true,
           }}
           variant="outlined"
-          value={titleQuery}
-          onChange={e => setTitleQuery(e.target.value)}
+          value={query}
+          onChange={handleQueryUpdate}
+          error={error}
+          helperText={error}
       />
     </Container>
   </Paper>
-    <h1>Results</h1>
+      <Typography variant="h5" className={classes.searchBar}>Number of rules found: {numberOfHits}</Typography>
     <ul>
       {resultsDisplay}
     </ul>
+    <Pagination count={totalPages} page={pageNumber} siblingCount={2}
+      onChange={(event, value) => setPageNumber(value)}
+      />
+    <Paper/>
     </div>
   )
 }

frontend/src/utils/routing.js

@@ -0,0 +1,53 @@
+import React, { useState } from "react";
+import { useLocation, useHistory } from "react-router-dom";
+
+
+export function useLocationSearch() {
+  const location = useLocation();
+  const history = useHistory();
+
+  function setLocationSearch(searchParams, push=true) {
+    const search = new URLSearchParams(location.search);
+
+    for (const [key, value] of Object.entries(searchParams)) {
+      search.set(key, value);
+    }
+    
+    if (push) {
+      history.push(`${location.pathname}?${search.toString()}`);
+    } else {
+      history.replace(`${location.pathname}?${search.toString()}`);
+    }
+  }
+
+  return [new URLSearchParams(location.search), setLocationSearch];
+}
+
+export function useLocationSearchState(name, defaultValue, convert=value=>value) {
+  const [state, setState] = useState(defaultValue);
+  const location = useLocation();
+  const history = useHistory();
+
+  React.useEffect(() => {
+    const search = new URLSearchParams(location.search);
+    if (search.has(name) && search.get(name) != state) {
+      setState(convert(search.get(name)));
+    } else if (!search.has(name) && state != defaultValue) {
+      setState(defaultValue);
+    }
+  }, [location, history]);
+
+  function setSearchParam(value, {push=true, skipURI=false} = {}) {
+    const search = new URLSearchParams(location.search);
+
+    search.set(name, value);
+    setState(value);
+    if (push) {
+      history.push(`${location.pathname}?${search.toString()}`);
+    } else {
+      history.replace(`${location.pathname}?${search.toString()}`);
+    }
+  }
+
+  return [state, setSearchParam];
+}

frontend/src/utils/useSearch.js

@@ -4,7 +4,7 @@ import * as lunr from 'lunr'
 
 import { useFetch } from './useFetch';
 
-export function useSearch(query) {
+export function useSearch(query, pageSize, pageNumber) {
   let indexDataUrl = `${process.env.PUBLIC_URL}/rules/rule-index.json`;
   let storeDataUrl = `${process.env.PUBLIC_URL}/rules/rule-index-store.json`;
 
@@ -12,6 +12,8 @@ export function useSearch(query) {
   const [storeData, storeDataError, storeDataIsLoading] = useFetch(storeDataUrl);
 
   const [results, setResults] = useState([]);
+  const [numberOfHits, setNumberOfHits] = useState(null);
+  const [error, setError] = useState(null);
   const [resultsAreloading, setResultsAreLoading] = useState(true);
 
   React.useEffect(() => {
@@ -23,11 +25,25 @@ export function useSearch(query) {
       if (query) {
         finalQuery = `titles:${query}`
       }
-      const hits = index.search(finalQuery);
-      setResults(hits.map(({ ref }) => storeData[ref]));
+
+      let hits = []
+      setError(null);
+      try {
+        hits = index.search(finalQuery);
+      } catch (exception) {
+        if (exception instanceof lunr.QueryParseError) {
+          setError(exception.message);
+        } else {
+          throw exception;
+        }
+      }
+      setNumberOfHits(hits.length)
+      // const pageResults = hits;
+      const pageResults = hits.slice(pageSize*(pageNumber - 1), pageSize*(pageNumber));
+      setResults(pageResults.map(({ ref }) => storeData[ref]));
       setResultsAreLoading(false);
     }
-  }, [query, indexData, storeData, indexDataError, storeDataError, indexDataIsLoading, storeDataIsLoading]);
+  }, [query, pageSize, pageNumber, error, indexData, storeData, indexDataError, storeDataError, indexDataIsLoading, storeDataIsLoading]);
 
-  return [results, resultsAreloading];
+  return [results, numberOfHits, error, resultsAreloading];
 }