From 69b48de0af1e5799d3eb7eb7d3de96b3cc2e408a Mon Sep 17 00:00:00 2001
From: Andrey Smirnov <Smirnov.Andrey@gmail.com>
Date: Sun, 19 Jan 2014 12:57:15 +0400
Subject: [PATCH] Command aptly snapshot merge.

---
 cmd_snapshot.go | 65 +++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 65 insertions(+)

diff --git a/cmd_snapshot.go b/cmd_snapshot.go
index fd6862f0..fd4fac64 100644
--- a/cmd_snapshot.go
+++ b/cmd_snapshot.go
@@ -427,6 +427,54 @@ func aptlySnapshotDiff(cmd *commander.Command, args []string) error {
 	return err
 }
 
+func aptlySnapshotMerge(cmd *commander.Command, args []string) error {
+	var err error
+	if len(args) < 2 {
+		cmd.Usage()
+		return err
+	}
+
+	snapshotCollection := debian.NewSnapshotCollection(context.database)
+
+	sources := make([]*debian.Snapshot, len(args)-1)
+
+	for i := 0; i < len(args)-1; i++ {
+		sources[i], err = snapshotCollection.ByName(args[i+1])
+		if err != nil {
+			return fmt.Errorf("unable to load snapshot: %s", err)
+		}
+
+		err = snapshotCollection.LoadComplete(sources[i])
+		if err != nil {
+			return fmt.Errorf("unable to load snapshot: %s", err)
+		}
+	}
+
+	result := sources[0].RefList()
+
+	for i := 1; i < len(sources); i++ {
+		result = result.Merge(sources[i].RefList())
+	}
+
+	sourceDescription := make([]string, len(sources))
+	for i, s := range sources {
+		sourceDescription[i] = fmt.Sprintf("'%s'", s.Name)
+	}
+
+	// Create <destination> snapshot
+	destination := debian.NewSnapshotFromRefList(args[0], sources, result,
+		fmt.Sprintf("Merged from sources: %s", strings.Join(sourceDescription, ", ")))
+
+	err = snapshotCollection.Add(destination)
+	if err != nil {
+		return fmt.Errorf("unable to create snapshot: %s", err)
+	}
+
+	fmt.Printf("\nSnapshot %s successfully created.\nYou can run 'aptly publish snapshot %s' to publish snapshot as Debian repository.\n", destination.Name, destination.Name)
+
+	return err
+}
+
 func makeCmdSnapshotCreate() *commander.Command {
 	cmd := &commander.Command{
 		Run:       aptlySnapshotCreate,
@@ -524,6 +572,22 @@ Displays list of missing and new packages, difference in package versions betwee
 	return cmd
 }
 
+func makeCmdSnapshotMerge() *commander.Command {
+	cmd := &commander.Command{
+		Run:       aptlySnapshotMerge,
+		UsageLine: "merge <destination> <source> [<source>...]",
+		Short:     "merges snapshots into one, replacing matching packages",
+		Long: `
+Merge merges several snapshots into one. Merge happens from left to right. Packages with the same
+name-architecture pair are replaced during merge (package from latest snapshot on the list wins).
+If specified with only one snapshot, merge copies source into destination.
+`,
+		Flag: *flag.NewFlagSet("aptly-snapshot-merge", flag.ExitOnError),
+	}
+
+	return cmd
+}
+
 func makeCmdSnapshot() *commander.Command {
 	return &commander.Command{
 		UsageLine: "snapshot",
@@ -535,6 +599,7 @@ func makeCmdSnapshot() *commander.Command {
 			makeCmdSnapshotVerify(),
 			makeCmdSnapshotPull(),
 			makeCmdSnapshotDiff(),
+			makeCmdSnapshotMerge(),
 			//makeCmdSnapshotDestroy(),
 		},
 		Flag: *flag.NewFlagSet("aptly-snapshot", flag.ExitOnError),