page numbering engine

model/page/numbering.go

@@ -0,0 +1,74 @@
+// Copyright 2016 Documize Inc. <legal@documize.com>. All rights reserved.
+//
+// This software (Documize Community Edition) is licensed under
+// GNU AGPL v3 http://www.gnu.org/licenses/agpl-3.0.en.html
+//
+// You can operate outside the AGPL restrictions by purchasing
+// Documize Enterprise Edition and obtaining a commercial license
+// by contacting <sales@documize.com>.
+//
+// https://documize.com
+
+package page
+
+import (
+	"fmt"
+)
+
+// Numberize calculates numbers for pages, e.g. 1, 1.1, 2.2.1
+// that form a document's Table of Contents.
+//
+func Numberize(pages []Page) {
+	// index := 1
+	var prevPageLevel uint64
+	parts := []int{1} // we store 1, 1, 2, and then generate numbering as "1.1.2"
+
+	for i, p := range pages {
+		// handle bad data
+		if p.Level == 0 {
+			p.Level = 1
+		}
+
+		// increment level numbers each time we encounter age level of 1
+		// if p.Level == 1 {
+		// 	index++
+		// 	parts = []int{index}
+		// } else if p.Level == prevPageLevel {
+		// 	parts[len(parts)-1]++
+		// }
+
+		if i != 0 {
+			// we ...
+			if p.Level > prevPageLevel {
+				parts = append(parts, 1)
+			}
+
+			if p.Level == prevPageLevel {
+				parts[len(parts)-1]++
+			}
+
+			if p.Level < prevPageLevel {
+				end := (prevPageLevel - p.Level)
+				if int(end) > len(parts) {
+					end = uint64(len(parts))
+				}
+				parts = parts[0 : len(parts)-int(end)]
+				parts[len(parts)-1]++
+			}
+		}
+
+		// generate numbering for page using parts array
+		numbering := ""
+		for i, v := range parts {
+			dot := ""
+			if i != len(parts)-1 {
+				dot = "."
+			}
+			numbering = fmt.Sprintf("%s%d%s", numbering, v, dot)
+		}
+		pages[i].Numbering = numbering
+
+		// update state
+		prevPageLevel = p.Level
+	}
+}