1 files changed, 199 insertions, 0 deletions
diff --git a/endpoint_export_choices.go b/endpoint_export_choices.go
new file mode 100644
index 0000000..890f170
--- /dev/null
+++ b/endpoint_export_choices.go
@@ -0,0 +1,199 @@
+/*
+ * Staff page
+ *
+ * Copyright (C) 2024  Runxi Yu <https://runxiyu.org>
+ * SPDX-License-Identifier: AGPL-3.0-or-later
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+package main
+
+import (
+	"encoding/csv"
+	"fmt"
+	"net/http"
+	"strings"
+)
+
+func handleExportChoices(w http.ResponseWriter, req *http.Request) {
+	_, _, department, err := getUserInfoFromRequest(req)
+	if err != nil {
+		wstr(
+			w,
+			http.StatusInternalServerError,
+			fmt.Sprintf("Error: %v", err),
+		)
+	}
+	if department != staffDepartment {
+		wstr(
+			w,
+			http.StatusForbidden,
+			"You are not authorized to view this page",
+		)
+		return
+	}
+
+	type userCacheT struct {
+		Name       string
+		StudentID  string
+		Department string
+	}
+	userCacheMap := make(map[string]userCacheT)
+
+	rows, err := db.Query(req.Context(), "SELECT userid, courseid FROM choices")
+	if err != nil {
+		wstr(
+			w,
+			http.StatusInternalServerError,
+			"Unexpected database error",
+		)
+		return
+	}
+	output := make([][]string, 0)
+	for {
+		if !rows.Next() {
+			err := rows.Err()
+			if err != nil {
+				wstr(
+					w,
+					http.StatusInternalServerError,
+					"Unexpected database error",
+				)
+				return
+			}
+			break
+		}
+		var currentUserID, currentUserName, currentStudentID, currentDepartment string
+		var currentCourseID int
+		err := rows.Scan(&currentUserID, &currentCourseID)
+		if err != nil {
+			wstr(
+				w,
+				http.StatusInternalServerError,
+				"Unexpected database error",
+			)
+			return
+		}
+		currentUserCache, ok := userCacheMap[currentUserID]
+		if ok {
+			currentUserName = currentUserCache.Name
+			currentDepartment = currentUserCache.Department
+			currentStudentID = currentUserCache.StudentID
+		} else {
+			var currentUserEmail string
+			err := db.QueryRow(
+				req.Context(),
+				"SELECT name, email, department FROM users WHERE id = $1",
+				currentUserID,
+			).Scan(
+				&currentUserName,
+				&currentUserEmail,
+				&currentDepartment,
+			)
+			if err != nil {
+				wstr(
+					w,
+					http.StatusInternalServerError,
+					"Unexpected database error",
+				)
+				return
+			}
+			before, _, found := strings.Cut(currentUserEmail, "@")
+			if found {
+				currentStudentID, _ = strings.CutPrefix(before, "s")
+			} else {
+				currentStudentID = currentUserEmail
+			}
+			userCacheMap[currentUserID] = userCacheT{
+				Name:       currentUserName,
+				StudentID:  currentStudentID,
+				Department: currentDepartment,
+			}
+		}
+
+		_course, ok := courses.Load(currentCourseID)
+		if !ok {
+			wstr(
+				w,
+				http.StatusInternalServerError,
+				"Reference to non-existent course",
+			)
+			return
+		}
+		course, ok := _course.(*courseT)
+		if !ok {
+			panic("courses map has non-\"*courseT\" items")
+		}
+		if course == nil {
+			wstr(
+				w,
+				http.StatusInternalServerError,
+				"Course is nil",
+			)
+			return
+		}
+		output = append(
+			output,
+			[]string{
+				currentUserName,
+				currentStudentID,
+				currentDepartment,
+				course.Title,
+				course.Group,
+				course.SectionID,
+				course.CourseID,
+			},
+		)
+	}
+
+	w.Header().Set("Content-Type", "text/csv; charset=utf-8")
+	w.Header().Set("Content-Disposition", "attachment;filename=cca_choices.csv")
+	csvWriter := csv.NewWriter(w)
+	err = csvWriter.Write([]string{
+		"Student Name",
+		"Student ID",
+		"Grade/Year",
+		"Group/Activity",
+		"Container",
+		"Section ID",
+		"Course ID",
+	})
+	if err != nil {
+		wstr(
+			w,
+			http.StatusInternalServerError,
+			"Error writing output",
+		)
+		return
+	}
+	err = csvWriter.WriteAll(output)
+	if err != nil {
+		wstr(
+			w,
+			http.StatusInternalServerError,
+			"Error writing output",
+		)
+		return
+	}
+	csvWriter.Flush()
+	if csvWriter.Error() != nil {
+		wstr(
+			w,
+			http.StatusInternalServerError,
+			"Error occurred flushing output",
+		)
+		return
+	}
+}