From dd98ae492bfd7701c8a87356c39ff29539dfadcc Mon Sep 17 00:00:00 2001
From: bouncepaw <bouncepaw2@ya.ru>
Date: Sun, 31 Jan 2021 00:25:18 +0500
Subject: [PATCH] Start moving universal link-related stuff to a separate
 module

---
 link/link.go   | 107 +++++++++++++++++++++++++++++++++++++++++++++++++
 markup/link.go |  39 ++++--------------
 2 files changed, 114 insertions(+), 32 deletions(-)
 create mode 100644 link/link.go

diff --git a/link/link.go b/link/link.go
new file mode 100644
index 0000000..3f9b9c4
--- /dev/null
+++ b/link/link.go
@@ -0,0 +1,107 @@
+package link
+
+import (
+	"fmt"
+	"path"
+	"strings"
+
+	"github.com/bouncepaw/mycorrhiza/util"
+)
+
+// LinkType tells what type the given link is.
+type LinkType int
+
+const (
+	LinkInavild LinkType = iota
+	// LinkLocalRoot is a link like "/list", "/user-list", etc.
+	LinkLocalRoot
+	// LinkLocalHypha is a link like "test", "../test", etc.
+	LinkLocalHypha
+	// LinkExternal is an external link with specified protocol.
+	LinkExternal
+	// LinkInterwiki is currently unused.
+	LinkInterwiki
+)
+
+// Link is an abstraction for universal representation of links, be they links in mycomarkup links or whatever.
+type Link struct {
+	// Address is what the link points to.
+	Address string
+	// Display is what gets nested into the <a> tag.
+	Display            string
+	Kind               LinkType
+	DestinationUnknown bool
+
+	Protocol string
+	// How the link address looked originally in source text.
+	SrcAddress string
+	// How the link display text looked originally in source text. May be empty.
+	SrcDisplay string
+	// RelativeTo is hypha name to which the link is relative to.
+	RelativeTo string
+}
+
+// Classes returns CSS class string for given link.
+func (l *Link) Classes() string {
+	if l.Kind == LinkExternal {
+		return fmt.Sprintf("wikilink wikilink_external wikilink_%s", l.Protocol)
+	}
+	classes := "wikilink wikilink_internal"
+	if l.DestinationUnknown {
+		classes += " wikilink_new"
+	}
+	return classes
+}
+
+// Href returns content for the href attrubite. You should always use it.
+func (l *Link) Href() string {
+	switch l.Kind {
+	case LinkExternal, LinkLocalRoot:
+		return l.Address
+	default:
+		return "/hypha/" + l.Address
+	}
+}
+
+// From returns a Link object given these `address` and `display` on relative to given `hyphaName`.
+func From(address, display, hyphaName string) *Link {
+	link := Link{
+		SrcAddress: address,
+		SrcDisplay: display,
+		RelativeTo: hyphaName,
+	}
+
+	if display == "" {
+		link.Display = address
+	} else {
+		link.Display = strings.TrimSpace(display)
+	}
+
+	switch {
+	case strings.ContainsRune(address, ':'):
+		pos := strings.IndexRune(address, ':')
+		link.Protocol = address[:pos]
+		link.Kind = LinkExternal
+
+		if display == "" {
+			link.Display = address[pos+1:]
+			if strings.HasPrefix(link.Display, "//") && len(link.Display) > 2 {
+				link.Display = link.Display[2:]
+			}
+		}
+		link.Address = address
+	case strings.HasPrefix(address, "/"):
+		link.Address = address
+		link.Kind = LinkLocalRoot
+	case strings.HasPrefix(address, "./"):
+		link.Kind = LinkLocalHypha
+		link.Address = util.CanonicalName(path.Join(hyphaName, address[2:]))
+	case strings.HasPrefix(address, "../"):
+		link.Kind = LinkLocalHypha
+		link.Address = util.CanonicalName(path.Join(path.Dir(hyphaName), address[3:]))
+	default:
+		link.Address = util.CanonicalName(address)
+	}
+
+	return &link
+}
diff --git a/markup/link.go b/markup/link.go
index af3e51c..9243fca 100644
--- a/markup/link.go
+++ b/markup/link.go
@@ -1,47 +1,22 @@
 package markup
 
 import (
-	"fmt"
-	"path"
 	"strings"
+
+	"github.com/bouncepaw/mycorrhiza/link"
 )
 
 // LinkParts determines what href, text and class should resulting <a> have based on mycomarkup's addr, display and hypha name.
 //
 // => addr display
 // [[addr|display]]
+// TODO: deprecate
 func LinkParts(addr, display, hyphaName string) (href, text, class string) {
-	if display == "" {
-		text = addr
-	} else {
-		text = strings.TrimSpace(display)
+	l := link.From(addr, display, hyphaName)
+	if l.Kind == link.LinkLocalHypha && !HyphaExists(l.Address) {
+		l.DestinationUnknown = true
 	}
-	class = "wikilink wikilink_internal"
-
-	switch {
-	case strings.ContainsRune(addr, ':'):
-		pos := strings.IndexRune(addr, ':')
-		destination := addr[:pos]
-		if display == "" {
-			text = addr[pos+1:]
-			if strings.HasPrefix(text, "//") && len(text) > 2 {
-				text = text[2:]
-			}
-		}
-		return addr, text, fmt.Sprintf("wikilink wikilink_external wikilink_%s", destination)
-	case strings.HasPrefix(addr, "/"):
-		return addr, text, class
-	case strings.HasPrefix(addr, "./"):
-		hyphaName = canonicalName(path.Join(hyphaName, addr[2:]))
-	case strings.HasPrefix(addr, "../"):
-		hyphaName = canonicalName(path.Join(path.Dir(hyphaName), addr[3:]))
-	default:
-		hyphaName = canonicalName(addr)
-	}
-	if !HyphaExists(hyphaName) {
-		class += " wikilink_new"
-	}
-	return "/page/" + hyphaName, text, class
+	return l.Href(), l.Display, l.Classes()
 }
 
 // Parse markup line starting with "=>" according to wikilink rules.