filters, sort orders, beginning of data structure

asymptome.lua

@@ -2,6 +2,17 @@
 local json = require "lib.dkjson"
 math.randomseed(os.time())
 
+local default_file = "books.json"
+
+local path_exists = function(path_name)
+  local file = io.open(path_name, "r")
+  if file then
+    file:close()
+    return true
+  end
+  return false
+end
+
 local load_json = function(file_name)
   local file, error_message = io.open(file_name, "r")
   assert(file, error_message)
@@ -18,7 +29,7 @@ local save_json = function(file_name, data)
   file:close()
 end
 
-local random_order = function(array)
+local get_random_order = function(array)
   local temporary, order = {}, {}
   for i = 1, #array do
     temporary[i] = i
@@ -28,3 +39,67 @@ local random_order = function(array)
   end
   return order
 end
+
+local filters = {
+  unread = function(book)
+    if book.progress == 0 then
+      return true
+    end
+    return false
+  end,
+  read = function(book)
+    if book.progress == 1 then
+      return true
+    end
+    return false
+  end,
+  in_progress = function(book)
+    if book.progress > 0 and book.progress < 1 then
+      return true
+    end
+    return false
+  end,
+}
+
+local sort_orders
+sort_orders = {
+  most_progress = function(A, B)
+    return A.progress > B.progress
+  end,
+  least_progress = function(A, B)
+    return A.progress < B.progress
+  end,
+  highest_priority = function(A, B)
+    return A.priority > B.priority
+  end,
+  lowest_priority = function(A, B)
+    return A.priority < B.priority
+  end,
+  most_pages_remaining = function(A, B)
+    if not (A.pages and B.pages) then -- if pages is unknown for both, fallback to percentage
+      return A.progress > B.progress
+    end
+    local average_page_count = data.total_pages / #data.books
+    local a = (A.pages or average_page_count) - (A.pages or average_page_count) * A.progress
+    local b = (B.pages or average_page_count) - (B.pages or average_page_count) * B.progress
+    return a > b
+  end,
+  fewest_pages_remaining = function(A, B)
+    return not sort_orders.most_pages_remaining(A, B)
+  end,
+}
+
+local data
+if path_exists(default_file) then
+  data = load_json(default_file)
+  -- TODO verify data structure
+else
+  data = {
+    books = {},
+    elo = {
+      distance_constant = 5,
+      maximum_change = 2.5,
+    },
+    total_pages = 0,
+  }
+end