Some serious layout changes

controllers/filter_controller.go

@@ -140,12 +140,80 @@ func GetQuickFilter(kgpz *xmlmodels.Library) fiber.Handler {
 			return strings.Compare(a.ID, b.ID)
 		})
 
+		// Get all categories with their first available year
+		categories := make([]CategorySummary, 0)
+		categoryYears := make(map[string][]int) // categoryID -> list of years
+
+		// First pass: collect all years for each category
+		for _, piece := range kgpz.Pieces.Array {
+			// Get years for this piece
+			pieceYears := make(map[int]bool)
+			for _, issueRef := range piece.IssueRefs {
+				if issueRef.When.Year > 0 {
+					pieceYears[issueRef.When.Year] = true
+				}
+			}
+
+			// Process CategoryRefs
+			for _, catRef := range piece.CategoryRefs {
+				if catRef.Ref != "" {
+					for year := range pieceYears {
+						categoryYears[catRef.Ref] = append(categoryYears[catRef.Ref], year)
+					}
+				}
+			}
+
+			// Process WorkRefs with categories (rezension)
+			for _, workRef := range piece.WorkRefs {
+				categoryID := workRef.Category
+				if categoryID == "" {
+					categoryID = "rezension" // Default category for WorkRefs
+				}
+				for year := range pieceYears {
+					categoryYears[categoryID] = append(categoryYears[categoryID], year)
+				}
+			}
+		}
+
+		// Build categories list with first year for each
+		kgpz.Categories.Lock()
+		for _, category := range kgpz.Categories.Array {
+			if yearsList, exists := categoryYears[category.ID]; exists && len(yearsList) > 0 {
+				// Find the earliest year for this category
+				slices.Sort(yearsList)
+				firstYear := yearsList[0]
+
+				// Get the primary name (first name in the list)
+				var name string
+				if len(category.Names) > 0 {
+					name = category.Names[0]
+				} else {
+					name = category.ID // fallback to ID if no names
+				}
+
+				categorySummary := CategorySummary{
+					ID:        category.ID,
+					Name:      name,
+					FirstYear: firstYear,
+				}
+
+				categories = append(categories, categorySummary)
+			}
+		}
+		kgpz.Categories.Unlock()
+
+		// Sort categories list by name
+		slices.SortFunc(categories, func(a, b CategorySummary) int {
+			return strings.Compare(a.Name, b.Name)
+		})
+
 		// Prepare data for the filter template
 		data := fiber.Map{
 			"AvailableYears":    availableYears,
 			"Persons":           persons,
 			"Authors":           authors,
 			"Places":            places,
+			"Categories":        categories,
 			"IssuesByYearJSON":  string(issuesByYearJSON),
 		}
 
@@ -168,6 +236,13 @@ type PlaceSummary struct {
 	Geo  string
 }
 
+// CategorySummary represents a simplified category for the filter list
+type CategorySummary struct {
+	ID        string
+	Name      string
+	FirstYear int
+}
+
 // IssueSummary represents an issue for the Jahr/Ausgabe filter
 type IssueSummary struct {
 	Number int    `json:"number"`

controllers/kategorie_controller.go

@@ -1,12 +1,111 @@
 package controllers
 
 import (
+	"slices"
+	"strconv"
+	"strings"
+
+	"github.com/Theodor-Springmann-Stiftung/kgpz_web/helpers/logging"
+	"github.com/Theodor-Springmann-Stiftung/kgpz_web/viewmodels"
 	"github.com/Theodor-Springmann-Stiftung/kgpz_web/xmlmodels"
 	"github.com/gofiber/fiber/v2"
 )
 
+const (
+	DEFAULT_CATEGORY = ""
+)
+
 func GetCategory(kgpz *xmlmodels.Library) fiber.Handler {
 	return func(c *fiber.Ctx) error {
-		return c.Render("/kategorie/", nil)
+		categoryID := c.Params("category", DEFAULT_CATEGORY)
+		categoryID = strings.ToLower(categoryID)
+		yearParam := c.Params("year", "")
+
+		// Case 1: No category specified - show categories list with years
+		if categoryID == "" {
+			categories := viewmodels.CategoriesView(kgpz)
+			if len(categories.Categories) == 0 {
+				logging.Error(nil, "No categories found")
+				return c.SendStatus(fiber.StatusNotFound)
+			}
+			return c.Render("/kategorie/list/", fiber.Map{
+				"model": categories,
+			})
+		}
+
+		// Case 2: Both category and year specified - show pieces
+		if yearParam != "" {
+			year, err := strconv.Atoi(yearParam)
+			if err != nil {
+				logging.Error(err, "Invalid year parameter: "+yearParam)
+				return c.SendStatus(fiber.StatusBadRequest)
+			}
+
+			categoryPieces := viewmodels.NewCategoryPiecesView(categoryID, year, kgpz)
+			if categoryPieces == nil {
+				logging.Error(nil, "Category not found: "+categoryID)
+				return c.SendStatus(fiber.StatusNotFound)
+			}
+
+			return c.Render("/kategorie/pieces/", fiber.Map{
+				"model": categoryPieces,
+			})
+		}
+
+		// Case 3: Category specified but no year - find first available year and redirect
+		firstYear := findFirstYearForCategory(categoryID, kgpz)
+		if firstYear == 0 {
+			// Category exists but has no pieces, redirect to category list
+			logging.Error(nil, "Category has no pieces: "+categoryID)
+			return c.Redirect("/kategorie/")
+		}
+
+		// Redirect to category with first available year
+		return c.Redirect("/kategorie/" + categoryID + "/" + strconv.Itoa(firstYear))
 	}
 }
+
+// findFirstYearForCategory finds the earliest year that has pieces for the given category
+func findFirstYearForCategory(categoryID string, kgpz *xmlmodels.Library) int {
+	categoryYears := make([]int, 0)
+
+	for _, piece := range kgpz.Pieces.Array {
+		matchesCategory := false
+
+		// Check direct CategoryRefs
+		for _, catRef := range piece.CategoryRefs {
+			if catRef.Ref == categoryID {
+				matchesCategory = true
+				break
+			}
+		}
+
+		// Check WorkRefs with categories if not found in direct refs
+		if !matchesCategory {
+			for _, workRef := range piece.WorkRefs {
+				if workRef.Category == categoryID || (workRef.Category == "" && categoryID == "rezension") {
+					matchesCategory = true
+					break
+				}
+			}
+		}
+
+		if matchesCategory {
+			// Extract years from IssueRefs
+			for _, issueRef := range piece.IssueRefs {
+				year := issueRef.When.Year
+				if year > 0 {
+					categoryYears = append(categoryYears, year)
+				}
+			}
+		}
+	}
+
+	if len(categoryYears) == 0 {
+		return 0 // No pieces found for this category
+	}
+
+	// Find the earliest year
+	slices.Sort(categoryYears)
+	return categoryYears[0]
+}