refactor: switched cache size calculation from SQL to MBTiles file metrics

 - removed `SUM(length(tile_data))` from `ViewHelpers#get_tiles_size`; size is now computed via route_storage_files`
 - added `DB_SIDECAR_SUFFIXES`, `mbtiles_related_paths`, `resolve_mbtiles_path`, `progress_json_path`, and `format_bytes` to handle `.mbtiles`, `-wal`, `-shm`, and `.progress.json`
 - updated "Cache Size" in `database.slim` to use `format_bytes(get_tiles_size(@route))`
 - added a `Storage Files` section in `database.slim` showing file list, `exists/missing` status, and per-file size
 - switched progress JSON lookup in `database.slim` to `progress_json_path(@route)` with support for both absolute and relative `mbtiles_file` paths

Author: Efreh

src/view_helpers.rb

@@ -3,9 +3,39 @@
 require_relative 'geometry_tile_calculator'
 
 module ViewHelpers
-  def get_tiles_size(route)
-    db = route[:db]
-    db.table_exists?(:tiles) ? (db[:tiles].sum(Sequel.function(:length, :tile_data)) || 0) : 0
+  DB_SIDECAR_SUFFIXES = ['-wal', '-shm'].freeze
+
+  def get_tiles_size(route) = route_storage_files(route).sum { _1[:size] }
+
+  def route_storage_files(route)
+    mbtiles_related_paths(route[:mbtiles_file]).map do |path|
+      exists = File.exist?(path)
+      {
+        path: path,
+        name: File.basename(path),
+        exists: exists,
+        size: exists ? File.size(path) : 0
+      }
+    end
+  end
+
+  def progress_json_path(route)
+    mbtiles_path = resolve_mbtiles_path(route[:mbtiles_file])
+    mbtiles_path&.end_with?('.mbtiles') ? mbtiles_path.sub(/\.mbtiles$/, '.progress.json') : nil
+  end
+
+  def format_bytes(bytes)
+    units = %w[B KB MB GB TB]
+    size = bytes.to_f
+    unit_index = 0
+
+    while size >= 1024 && unit_index < units.length - 1
+      size /= 1024.0
+      unit_index += 1
+    end
+
+    precision = unit_index.zero? ? 0 : 2
+    "#{size.round(precision)} #{units[unit_index]}"
   end
 
   def tiles_per_zoom(z, route = nil)
@@ -305,4 +335,24 @@ def generate_single_source_style(route, source_name, debug_mode = false)
 
     style.to_json
   end
+
+  private
+
+  def mbtiles_related_paths(mbtiles_file)
+    mbtiles_path = resolve_mbtiles_path(mbtiles_file)
+    return [] unless mbtiles_path
+    return [mbtiles_path] unless mbtiles_path.end_with?('.mbtiles')
+
+    [mbtiles_path, *DB_SIDECAR_SUFFIXES.map { "#{mbtiles_path}#{_1}" }, mbtiles_path.sub(/\.mbtiles$/, '.progress.json')]
+  end
+
+  def resolve_mbtiles_path(mbtiles_file)
+    return nil if mbtiles_file.nil? || mbtiles_file.to_s.strip.empty?
+
+    path = mbtiles_file.to_s
+    return path if path.start_with?('/')
+
+    candidates = [File.expand_path(path, Dir.pwd), File.expand_path(path, __dir__)].uniq
+    candidates.find { |candidate| File.exist?(candidate) } || candidates.first
+  end
 end

src/views/database.slim

@@ -134,6 +134,7 @@ html
 
       .section
         .section-title Statistics
+        - storage_files = route_storage_files(@route)
         .stats-grid
           .stat-box
             .stat-number = @route[:db][:tiles].count
@@ -142,9 +143,30 @@ html
             .stat-number = @route[:db][:misses].count
             .stat-desc Cache Misses
           .stat-box
-            .stat-number = "#{((@route[:db][:tiles].sum(Sequel.function(:length, :tile_data)) || 0) / 1024.0 / 1024.0).round(2)} MB"
+            .stat-number = format_bytes(get_tiles_size(@route))
             .stat-desc Cache Size
 
+      .section
+        .section-title Storage Files
+        - if storage_files.empty?
+          .json-missing mbtiles_file is not configured.
+        - else
+          .table-container
+            table
+              thead
+                tr
+                  th File
+                  th Path
+                  th Size
+                  th Status
+              tbody
+                - storage_files.each do |file|
+                  tr
+                    td = file[:name]
+                    td = file[:path]
+                    td = format_bytes(file[:size])
+                    td = file[:exists] ? 'exists' : 'missing'
+
       .main-layout
         .sidebar
           .table-list
@@ -187,7 +209,7 @@ html
                 - if page < total_pages
                   a.pagination-btn href=url_for("/db?source=#{@source}&table=#{current_table}&page=#{page+1}") Next →
 
-      - json_path = @route[:mbtiles_file]&.sub(/\.mbtiles$/, '.progress.json')
+      - json_path = progress_json_path(@route)
       - json_content = json_path && File.exist?(json_path) ? File.read(json_path) : nil
       .section
         .section-title Progress JSON