Created Turnpike, event attendee and volunteer management

Built after prototype, Traverse, an attendee and volunteer list
maintainer.

handle_import.go

@@ -0,0 +1,158 @@
+package main
+
+import (
+	"encoding/csv"
+	"fmt"
+	"io"
+	"net/http"
+	"strings"
+)
+
+type ImportResult struct {
+	Inserted int      `json:"inserted"`
+	Grouped  int      `json:"grouped"`
+	Skipped  int      `json:"skipped"`
+	Errors   []string `json:"errors"`
+}
+
+func (app *App) handleImport(w http.ResponseWriter, r *http.Request) {
+	if err := r.ParseMultipartForm(10 << 20); err != nil {
+		writeError(w, "invalid form", http.StatusBadRequest)
+		return
+	}
+	file, _, err := r.FormFile("csv")
+	if err != nil {
+		writeError(w, "csv file required", http.StatusBadRequest)
+		return
+	}
+	defer file.Close()
+
+	result, err := app.importCSV(file)
+	if err != nil {
+		writeError(w, err.Error(), http.StatusBadRequest)
+		return
+	}
+	if result.Errors == nil {
+		result.Errors = []string{}
+	}
+	writeJSON(w, result)
+}
+
+func (app *App) importCSV(r io.Reader) (ImportResult, error) {
+	reader := csv.NewReader(r)
+	reader.TrimLeadingSpace = true
+	reader.LazyQuotes = true
+
+	header, err := reader.Read()
+	if err != nil {
+		return ImportResult{}, fmt.Errorf("reading header: %w", err)
+	}
+	if len(header) > 0 {
+		header[0] = strings.TrimPrefix(header[0], "\xef\xbb\xbf") // strip BOM
+	}
+
+	colIndex := make(map[string]int)
+	for i, h := range header {
+		colIndex[strings.ToLower(strings.TrimSpace(h))] = i
+	}
+
+	var (
+		nameIdx, emailIdx, ticketIDIdx, ticketTypeIdx, noteIdx int
+		hasEmail, hasTicketID, hasTicketType, hasNote          bool
+	)
+
+	if idx, ok := colIndex["patron name"]; ok {
+		// CrowdWork / ticketing platform format
+		nameIdx = idx
+		if idx, ok := colIndex["patron email"]; ok {
+			emailIdx, hasEmail = idx, true
+		}
+		if idx, ok := colIndex["tier name"]; ok {
+			ticketTypeIdx, hasTicketType = idx, true
+		}
+		if idx, ok := colIndex["order number"]; ok {
+			ticketIDIdx, hasTicketID = idx, true
+		}
+	} else if idx, ok := colIndex["name"]; ok {
+		// Generic format
+		nameIdx = idx
+		if idx, ok := colIndex["email"]; ok {
+			emailIdx, hasEmail = idx, true
+		}
+		if idx, ok := colIndex["ticket_id"]; ok {
+			ticketIDIdx, hasTicketID = idx, true
+		}
+		if idx, ok := colIndex["ticket_type"]; ok {
+			ticketTypeIdx, hasTicketType = idx, true
+		}
+		if idx, ok := colIndex["note"]; ok {
+			noteIdx, hasNote = idx, true
+		}
+	} else {
+		return ImportResult{}, fmt.Errorf("CSV must have a 'name' or 'patron name' column")
+	}
+
+	var result ImportResult
+	lineNum := 1
+
+	for {
+		record, err := reader.Read()
+		if err == io.EOF {
+			break
+		}
+		lineNum++
+		if err != nil {
+			result.Errors = append(result.Errors, fmt.Sprintf("line %d: %v", lineNum, err))
+			continue
+		}
+
+		name := strings.TrimSpace(csvGet(record, nameIdx))
+		if name == "" {
+			continue
+		}
+
+		a := Attendee{Name: name}
+		if hasEmail {
+			a.Email = strings.TrimSpace(csvGet(record, emailIdx))
+		}
+		if hasTicketID {
+			a.TicketID = strings.TrimSpace(csvGet(record, ticketIDIdx))
+		}
+		if hasTicketType {
+			a.TicketType = strings.TrimSpace(csvGet(record, ticketTypeIdx))
+		}
+		if hasNote {
+			a.Note = strings.TrimSpace(csvGet(record, noteIdx))
+		}
+
+		_, err = app.createAttendee(a)
+		if err != nil {
+			if strings.Contains(err.Error(), "UNIQUE constraint failed") {
+				// CrowdWork exports one row per ticket under the purchaser's name.
+				// If we have a ticket_id and the same (name, ticket_id) already exists,
+				// increment party_size instead of skipping.
+				if hasTicketID && a.TicketID != "" {
+					merged, mergeErr := app.incrementPartySize(a.Name, a.TicketID)
+					if mergeErr == nil && merged {
+						result.Grouped++
+						continue
+					}
+				}
+				result.Skipped++
+			} else {
+				result.Errors = append(result.Errors, fmt.Sprintf("line %d (%s): %v", lineNum, name, err))
+			}
+			continue
+		}
+		result.Inserted++
+	}
+
+	return result, nil
+}
+
+func csvGet(record []string, idx int) string {
+	if idx < len(record) {
+		return record[idx]
+	}
+	return ""
+}