UCSBGradeHistoryServiceImpl.java

package edu.ucsb.cs156.courses.services;

 import java.io.Reader;
 import java.io.StringReader;
 import java.util.ArrayList;
 import java.util.List;
 import java.util.Map;
 import java.util.stream.Collectors;

 import com.fasterxml.jackson.databind.ObjectMapper;
 import com.opencsv.CSVReader;

 import edu.ucsb.cs156.courses.entities.GradeHistory;
 import edu.ucsb.cs156.courses.models.Quarter;
 import edu.ucsb.cs156.courses.models.github.ApiResult;
 import edu.ucsb.cs156.courses.models.github.TreeElement;

 import org.springframework.web.client.RestTemplate;

 import lombok.extern.slf4j.Slf4j;

 import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.boot.web.client.RestTemplateBuilder;
 import org.springframework.http.HttpEntity;
 import org.springframework.http.HttpHeaders;
 import org.springframework.http.HttpMethod;
 import org.springframework.http.MediaType;
 import org.springframework.http.ResponseEntity;
 import org.springframework.stereotype.Service;

 @Service("UCSBGradeHistoryService")
 @Slf4j
 public class UCSBGradeHistoryServiceImpl implements UCSBGradeHistoryService {

     private final RestTemplate restTemplate;

     public UCSBGradeHistoryServiceImpl(RestTemplateBuilder restTemplateBuilder) {
         restTemplate = restTemplateBuilder.build();
     }

     @Autowired
     ObjectMapper mapper;

     public static final String REPO_OWNER_AND_NAME = "ucsb-cs156/UCSB_Grades";
     public static final String API_ENDPOINT = "https://api.github.com/repos/"
             + REPO_OWNER_AND_NAME +
             "/git/trees/main?recursive=1";

     @Override
     public List<String> getUrls() throws Exception {

         log.info("getting data from {}", API_ENDPOINT);

         HttpHeaders headers = new HttpHeaders();
         headers.setAccept(List.of(MediaType.APPLICATION_JSON));
         headers.setContentType(MediaType.APPLICATION_JSON);

         HttpEntity<String> entity = new HttpEntity<>(headers);
         Map<String, String> uriVariables = Map.of("recursive", "1");

         ResponseEntity<String> re = restTemplate.exchange(API_ENDPOINT, HttpMethod.GET, entity, String.class,
                 uriVariables);

         ApiResult apiResult = mapper.readValue(re.getBody(), ApiResult.class);

         List<TreeElement> treeElements = apiResult.getTree();
         List<String> urls = treeElements.stream().map(treeElement -> treeElement.getPath())
                 .filter(path -> (path.startsWith("quarters/") && path.endsWith(".csv"))).collect(Collectors.toList());
         List<String> rawUrls = urls.stream()
                 .map(url -> "https://raw.githubusercontent.com/" + REPO_OWNER_AND_NAME + "/main/" + url)
                 .collect(Collectors.toList());
         return rawUrls;
     }

     @Override
     public List<GradeHistory> getGradeData(String url) throws Exception {
         log.info("getting data from {}", url);
         HttpHeaders headers = new HttpHeaders();
         headers.setAccept(List.of(MediaType.APPLICATION_JSON));
         headers.setContentType(MediaType.APPLICATION_JSON);

         HttpEntity<String> entity = new HttpEntity<>(headers);
         ResponseEntity<String> re = restTemplate.exchange(url, HttpMethod.GET, entity, String.class);
         String csvData = re.getBody();
         return parse(new StringReader(csvData));
     }

     @Override
     public List<GradeHistory> parse(Reader reader) throws Exception {
         List<GradeHistory> gradeHistoryList = new ArrayList<GradeHistory>();
         log.info("Parsing CSV file with grade history... ");
         CSVReader csvReader = new CSVReader(reader);
         csvReader.skip(1);
         List<String[]> myEntries = csvReader.readAll();
         for (String[] row : myEntries) {
             String yyyyq = Integer.toString(Quarter.qyyToyyyyQ(row[0]));
             GradeHistory gradeHistory = GradeHistory.builder()
                     .yyyyq(yyyyq)
                     .course(row[2])
                     .instructor(row[3])
                     .grade(row[4])
                     .count(Integer.parseInt(row[5]))
                     .build();
             log.info("Parsed: " + gradeHistory.toString());
             gradeHistoryList.add(gradeHistory);
         }
         csvReader.close();
         return gradeHistoryList;
     }
 }