builder for file collections

core/src/main/groovy/com/muwire/core/collections/FileCollectionBuilder.groovy

@@ -0,0 +1,96 @@
+package com.muwire.core.collections
+
+import java.nio.file.Path
+import java.nio.file.Paths
+
+import com.muwire.core.InfoHash
+import com.muwire.core.Persona
+import com.muwire.core.SharedFile
+import com.muwire.core.files.FileTree
+
+import net.i2p.data.SigningPrivateKey
+
+class FileCollectionBuilder {
+    private long timestamp
+    private String root
+    private Persona author
+    private String comment = ""
+    private final Set<SharedFile> sharedFiles = new LinkedHashSet<>()
+    private SigningPrivateKey spk
+
+    public FileCollectionBuilder setRoot(String root) {
+        this.root = root
+        this
+    }
+    
+    public FileCollectionBuilder setTimestamp(long timestamp) {
+        this.timestamp = timestamp
+        this
+    }
+    
+    public FileCollectionBuilder setAuthor(Persona author) {
+        this.author = author
+        this
+    }
+    
+    public FileCollectionBuilder setComment(String comment) {
+        this.comment = comment
+        this
+    }
+    
+    public FileCollectionBuilder setSPK(SigningPrivateKey spk) {
+        this.spk = spk
+        this
+    }
+    
+    public FileCollectionBuilder addFile(SharedFile sf) {
+        this.sharedFiles.add(sf)
+        this
+    }
+        
+    public FileCollection build() {
+        // TODO: check constraints
+        if (root == null || timestamp == 0 || author == null || comment == null || spk == null || sharedFiles.isEmpty())
+            throw new InvalidCollectionException()
+            
+        FileTree<Void> tree = new FileTree<>()
+        for(SharedFile sf : sharedFiles) 
+            tree.add(sf.file, null)
+        File common = tree.commonAncestor()
+
+        Map<SharedFile, Path> sfPaths = new LinkedHashMap<>()
+        for(SharedFile sf : sharedFiles) {
+            Path path = sf.file.toPath()
+            sfPaths.put(sf, path)
+        }
+        
+        if (common != null) {
+            Path commonPath = common.toPath()
+            for (SharedFile sf : sfPaths.keySet()) 
+                sfPaths.put(sf, commonPath.relativize(sfPaths.get(sf)))
+        }
+        
+        Map<SharedFile, LinkedList<String>> sfPathElements = new HashMap<>()
+        for (SharedFile sf : sfPaths.keySet()) {
+            LinkedList elements = new LinkedList()
+            for (Path p : sfPaths.get(sf))
+                elements.add(p.toString())
+            elements.addFirst(root)
+            sfPathElements.put(sf, elements)
+        }
+            
+        Set<FileCollectionItem> files = new LinkedHashSet<>()
+        for (SharedFile sf : sfPathElements.keySet()) {
+            String comment = sf.getComment() // TODO: check comment encoding
+            if (comment == null)
+                comment = ""
+            def item = new FileCollectionItem(new InfoHash(sf.root), comment, sfPathElements.get(sf))
+            files.add(item)
+        } 
+        
+        def rv = new FileCollection(timestamp, author, comment, files, spk)
+        rv
+    }
+    
+
+}