TODO: Create message index

dist/pigeon.rb

@@ -39,6 +39,9 @@ module Pigeon
   IDENTITY_SIGIL = "@"
   STRING_SIGIL = "\""
   BLOB_FOOTER = ".sha256"
+
+  # Error messages
+  PREV_REQUIRES_SAVE = "Can't fetch `prev` on unsaved messages"
 end
 
 require_relative File.join("pigeon", "key_pair.rb")

dist/pigeon/message.rb

@@ -2,22 +2,19 @@ require "digest"
 
 module Pigeon
   class Message
-    attr_reader :author, :kind, :prev, :body, :signature
+    attr_reader :author, :kind, :body, :signature
 
-    def self.create(kind:, prev: nil, body: {})
+    def self.create(kind:, body: {})
       self.new(author: KeyPair.current.public_key,
                kind: kind,
-               prev: prev,
                body: body).save
     end
 
-    def initialize(author:, kind:, prev: nil, body: {})
+    def initialize(author:, kind:, body: {})
       @author = author
       @kind = kind
-      @prev = prev
       @body = body
       @depth = nil # Set at save time
-      @prev = previous_message ? previous_message.signature : EMPTY_MESSAGE
     end
 
     def append(key, value)
@@ -51,6 +48,7 @@ module Pigeon
     def sign
       @signature = calculate_signature
       @depth = Pigeon::Storage.current.message_count
+      @saved = true
       self.freeze
       Pigeon::Storage.current.save_message(self)
       Pigeon::Message.reset_current
@@ -65,6 +63,18 @@ module Pigeon
       calculate_depth
     end
 
+    def prev
+      if @saved
+        previous_message
+      else
+        raise Pigeon::PREV_REQUIRES_SAVE
+      end
+    end
+
+    def saved?
+      @saved == true
+    end
+
     private
 
     def calculate_signature
@@ -74,6 +84,8 @@ module Pigeon
     end
 
     def previous_message
+      raise "TODO - I need to create a `Pigeon::Index` class or something. " \
+            "need a way to index messages by: signature, depth"
       # if @depth.nil?
       #   raise "Could not load @depth"
       # end
@@ -91,6 +103,7 @@ module Pigeon
     end
 
     def calculate_depth
+      raise "Don't do this- read from the index. Also, crash if message is not saved."
       @depth || Pigeon::Storage.current.message_count
     end
 

dist/pigeon/template.rb

@@ -25,7 +25,7 @@ module Pigeon
       body = message.body
       kind = message.kind
       depth = message.depth || "NONE"
-      prev = message.prev || "NONE"
+      prev = message.saved? ? message.prev : "NONE"
       signature = message.signature || "NONE"
 
       ERB.new(template).result(binding)

spec/pigeon/message_spec.rb

@@ -20,6 +20,7 @@ RSpec.describe Pigeon::Message do
 
     expect(message2.author).to eq(Pigeon::KeyPair.current.public_key)
     expect(message2.kind).to eq("unit_test")
+    binding.pry
     expect(message2.prev).to eq(m1)
     expect(message2.body).to eq("expected_sequence" => "1")
     expect(message2.depth).to eq(1)
@@ -65,6 +66,8 @@ RSpec.describe Pigeon::Message do
     expect(message.kind).to eq("unit_test")
     expect(message.body).to eq(expectations.fetch(:body))
     expect(message.depth).to eq(0)
+    message.sign
+    binding.pry
     expect(message.prev).to eq(Pigeon::EMPTY_MESSAGE)
     expectations.map do |k, v|
       expect(Pigeon::Message.current.send(k)).to eq(v)

spec/pigeon/template_spec.rb

@@ -1,7 +1,8 @@
 require "spec_helper"
 
 RSpec.describe Pigeon::Template do
-  MessageShim = Struct.new(:author, :body, :kind, :depth, :prev, :signature)
+  SHIM_ATTRS = [:author, :body, :kind, :depth, :prev, :signature, :saved?]
+  MessageShim = Struct.new(*SHIM_ATTRS)
   TOP_HALF = ["author FAKE_AUTHOR",
               "\nkind FAKE_KIND",
               "\nprev NONE",
@@ -16,7 +17,8 @@ RSpec.describe Pigeon::Template do
             "FAKE_KIND",
             23,
             nil,
-            "XYZ.sig.sha256"]
+            "XYZ.sig.sha256",
+            false]
     message = MessageShim.new(*args)
     template = Pigeon::Template.new(message)
     expect(template.render).to eq(EXPECTED_DRAFT)