Represent channels and messages using a split "History" and "Snapshot" model.

This separates the code that figures out what happened to an entity from the code that represents it to a user, and makes it easier to compute a snapshot at a point in time (for things like bootstrap). It also makes the internal logic a bit easier to follow, since it's easier to tell whether you're working with a point in time or with the whole recorded history.

This hefty.

11 files changed, 207 insertions, 187 deletions

diff --git a/.sqlx/query-74f0bad30dcec743d77309b8df33083c2da765dfda3023c78c25c06735670457.json b/.sqlx/query-1654b05159c27f74cb333586018161718e2a6788413bffffb252de3e1959f341.json
index b34443f..cc716ed 100644
--- a/.sqlx/query-74f0bad30dcec743d77309b8df33083c2da765dfda3023c78c25c06735670457.json
+++ b/.sqlx/query-1654b05159c27f74cb333586018161718e2a6788413bffffb252de3e1959f341.json
@@ -1,6 +1,6 @@
 {
   "db_name": "SQLite",
-  "query": "\n                select\n                    channel.id as \"id: Id\",\n                    channel.name,\n                    channel.created_at as \"created_at: DateTime\",\n                    channel.created_sequence as \"created_sequence: Sequence\"\n                from channel\n                    left join message\n                where created_at < $1\n                    and message.id is null\n            ",
+  "query": "\n                delete from channel\n                where id = $1\n                returning\n                    id as \"id: Id\",\n                    name,\n                    created_at as \"created_at: DateTime\",\n                    created_sequence as \"created_sequence: Sequence\"\n            ",
   "describe": {
     "columns": [
       {
@@ -34,5 +34,5 @@
       false
     ]
   },
-  "hash": "74f0bad30dcec743d77309b8df33083c2da765dfda3023c78c25c06735670457"
+  "hash": "1654b05159c27f74cb333586018161718e2a6788413bffffb252de3e1959f341"
 }
diff --git a/.sqlx/query-f5d5b3ec3554a80230e29676cdd9450fd1e8b4f2425cfda141d72fd94d3c39f9.json b/.sqlx/query-33f9a143409e6f436ed6b64abfbb9e06a5889460743202ca7956acabf006843e.json
index 7b1d2d8..1480953 100644
--- a/.sqlx/query-f5d5b3ec3554a80230e29676cdd9450fd1e8b4f2425cfda141d72fd94d3c39f9.json
+++ b/.sqlx/query-33f9a143409e6f436ed6b64abfbb9e06a5889460743202ca7956acabf006843e.json
@@ -1,10 +1,10 @@
 {
   "db_name": "SQLite",
-  "query": "\n                delete from message\n                where id = $1\n                returning 1 as \"row: i64\"\n            ",
+  "query": "\n                delete from message\n                where\n                    id = $1\n                returning 1 as \"deleted: i64\"\n            ",
   "describe": {
     "columns": [
       {
-        "name": "row: i64",
+        "name": "deleted: i64",
         "ordinal": 0,
         "type_info": "Null"
       }
@@ -16,5 +16,5 @@
       null
     ]
   },
-  "hash": "f5d5b3ec3554a80230e29676cdd9450fd1e8b4f2425cfda141d72fd94d3c39f9"
+  "hash": "33f9a143409e6f436ed6b64abfbb9e06a5889460743202ca7956acabf006843e"
 }
diff --git a/.sqlx/query-45449846ea98e892c6e58f2ba8e082c21c9e3d124e5340dec036edd341d94e0f.json b/.sqlx/query-45449846ea98e892c6e58f2ba8e082c21c9e3d124e5340dec036edd341d94e0f.json
new file mode 100644
index 0000000..2974cb0
--- /dev/null
+++ b/.sqlx/query-45449846ea98e892c6e58f2ba8e082c21c9e3d124e5340dec036edd341d94e0f.json
@@ -0,0 +1,26 @@
+{
+  "db_name": "SQLite",
+  "query": "\n\t\t\t\tinsert into message\n\t\t\t\t\t(id, channel, sender, sent_at, sent_sequence, body)\n\t\t\t\tvalues ($1, $2, $3, $4, $5, $6)\n\t\t\t\treturning\n\t\t\t\t\tid as \"id: Id\",\n\t\t\t\t\tbody\n\t\t\t",
+  "describe": {
+    "columns": [
+      {
+        "name": "id: Id",
+        "ordinal": 0,
+        "type_info": "Text"
+      },
+      {
+        "name": "body",
+        "ordinal": 1,
+        "type_info": "Text"
+      }
+    ],
+    "parameters": {
+      "Right": 6
+    },
+    "nullable": [
+      false,
+      false
+    ]
+  },
+  "hash": "45449846ea98e892c6e58f2ba8e082c21c9e3d124e5340dec036edd341d94e0f"
+}
diff --git a/.sqlx/query-4715007e2395ad30433b7405a144db4901c302bbcd3e76da6c61742ac44345c9.json b/.sqlx/query-4715007e2395ad30433b7405a144db4901c302bbcd3e76da6c61742ac44345c9.json
deleted file mode 100644
index 494e1db..0000000
--- a/.sqlx/query-4715007e2395ad30433b7405a144db4901c302bbcd3e76da6c61742ac44345c9.json
+++ /dev/null
@@ -1,44 +0,0 @@
-{
-  "db_name": "SQLite",
-  "query": "\n\t\t\t\tinsert into message\n\t\t\t\t\t(id, channel, sender, sent_at, sent_sequence, body)\n\t\t\t\tvalues ($1, $2, $3, $4, $5, $6)\n\t\t\t\treturning\n\t\t\t\t\tid as \"id: message::Id\",\n\t\t\t\t\tsender as \"sender: login::Id\",\n                    sent_at as \"sent_at: DateTime\",\n                    sent_sequence as \"sent_sequence: Sequence\",\n\t\t\t\t\tbody\n\t\t\t",
-  "describe": {
-    "columns": [
-      {
-        "name": "id: message::Id",
-        "ordinal": 0,
-        "type_info": "Text"
-      },
-      {
-        "name": "sender: login::Id",
-        "ordinal": 1,
-        "type_info": "Text"
-      },
-      {
-        "name": "sent_at: DateTime",
-        "ordinal": 2,
-        "type_info": "Text"
-      },
-      {
-        "name": "sent_sequence: Sequence",
-        "ordinal": 3,
-        "type_info": "Integer"
-      },
-      {
-        "name": "body",
-        "ordinal": 4,
-        "type_info": "Text"
-      }
-    ],
-    "parameters": {
-      "Right": 6
-    },
-    "nullable": [
-      false,
-      false,
-      false,
-      false,
-      false
-    ]
-  },
-  "hash": "4715007e2395ad30433b7405a144db4901c302bbcd3e76da6c61742ac44345c9"
-}
diff --git a/.sqlx/query-4d4dce1b034f4a540f49490b1a8433a8ca334f1d666b104823e3fb0c08efb2cc.json b/.sqlx/query-4d4dce1b034f4a540f49490b1a8433a8ca334f1d666b104823e3fb0c08efb2cc.json
new file mode 100644
index 0000000..fb5f94b
--- /dev/null
+++ b/.sqlx/query-4d4dce1b034f4a540f49490b1a8433a8ca334f1d666b104823e3fb0c08efb2cc.json
@@ -0,0 +1,32 @@
+{
+  "db_name": "SQLite",
+  "query": "\n                select\n                    channel.id as \"channel_id: channel::Id\",\n                    channel.name as \"channel_name\",\n                    message.id as \"message: Id\"\n                from message\n                    join channel on message.channel = channel.id\n                where sent_at < $1\n            ",
+  "describe": {
+    "columns": [
+      {
+        "name": "channel_id: channel::Id",
+        "ordinal": 0,
+        "type_info": "Text"
+      },
+      {
+        "name": "channel_name",
+        "ordinal": 1,
+        "type_info": "Text"
+      },
+      {
+        "name": "message: Id",
+        "ordinal": 2,
+        "type_info": "Text"
+      }
+    ],
+    "parameters": {
+      "Right": 1
+    },
+    "nullable": [
+      false,
+      false,
+      false
+    ]
+  },
+  "hash": "4d4dce1b034f4a540f49490b1a8433a8ca334f1d666b104823e3fb0c08efb2cc"
+}
diff --git a/.sqlx/query-5244f04bc270fc8d3cd4116854398e2151ba2dba10c03a9d2d93184141f1425c.json b/.sqlx/query-5244f04bc270fc8d3cd4116854398e2151ba2dba10c03a9d2d93184141f1425c.json
deleted file mode 100644
index 820b43f..0000000
--- a/.sqlx/query-5244f04bc270fc8d3cd4116854398e2151ba2dba10c03a9d2d93184141f1425c.json
+++ /dev/null
@@ -1,44 +0,0 @@
-{
-  "db_name": "SQLite",
-  "query": "\n                select\n                    channel.id as \"channel_id: channel::Id\",\n                    channel.name as \"channel_name\",\n                    channel.created_at as \"channel_created_at: DateTime\",\n                    channel.created_sequence as \"channel_created_sequence: Sequence\",\n                    message.id as \"message: message::Id\"\n                from message\n                    join channel on message.channel = channel.id\n                    join login as sender on message.sender = sender.id\n                where sent_at < $1\n            ",
-  "describe": {
-    "columns": [
-      {
-        "name": "channel_id: channel::Id",
-        "ordinal": 0,
-        "type_info": "Text"
-      },
-      {
-        "name": "channel_name",
-        "ordinal": 1,
-        "type_info": "Text"
-      },
-      {
-        "name": "channel_created_at: DateTime",
-        "ordinal": 2,
-        "type_info": "Text"
-      },
-      {
-        "name": "channel_created_sequence: Sequence",
-        "ordinal": 3,
-        "type_info": "Integer"
-      },
-      {
-        "name": "message: message::Id",
-        "ordinal": 4,
-        "type_info": "Text"
-      }
-    ],
-    "parameters": {
-      "Right": 1
-    },
-    "nullable": [
-      false,
-      false,
-      false,
-      false,
-      false
-    ]
-  },
-  "hash": "5244f04bc270fc8d3cd4116854398e2151ba2dba10c03a9d2d93184141f1425c"
-}
diff --git a/.sqlx/query-5c53579fa431b6e184faf94eedb8229360ba78f2607d25e7e2ee5db5c759a5a3.json b/.sqlx/query-5c53579fa431b6e184faf94eedb8229360ba78f2607d25e7e2ee5db5c759a5a3.json
new file mode 100644
index 0000000..4ca6786
--- /dev/null
+++ b/.sqlx/query-5c53579fa431b6e184faf94eedb8229360ba78f2607d25e7e2ee5db5c759a5a3.json
@@ -0,0 +1,62 @@
+{
+  "db_name": "SQLite",
+  "query": "\n                select\n                    channel.id as \"channel_id: channel::Id\",\n                    channel.name as \"channel_name\",\n                    sender.id as \"sender_id: login::Id\",\n                    sender.name as \"sender_name\",\n                    message.id as \"id: Id\",\n                    message.body,\n                    sent_at as \"sent_at: DateTime\",\n                    sent_sequence as \"sent_sequence: Sequence\"\n                from message\n                    join channel on message.channel = channel.id\n                    join login as sender on message.sender = sender.id\n                where coalesce(message.sent_sequence > $1, true)\n            ",
+  "describe": {
+    "columns": [
+      {
+        "name": "channel_id: channel::Id",
+        "ordinal": 0,
+        "type_info": "Text"
+      },
+      {
+        "name": "channel_name",
+        "ordinal": 1,
+        "type_info": "Text"
+      },
+      {
+        "name": "sender_id: login::Id",
+        "ordinal": 2,
+        "type_info": "Text"
+      },
+      {
+        "name": "sender_name",
+        "ordinal": 3,
+        "type_info": "Text"
+      },
+      {
+        "name": "id: Id",
+        "ordinal": 4,
+        "type_info": "Text"
+      },
+      {
+        "name": "body",
+        "ordinal": 5,
+        "type_info": "Text"
+      },
+      {
+        "name": "sent_at: DateTime",
+        "ordinal": 6,
+        "type_info": "Text"
+      },
+      {
+        "name": "sent_sequence: Sequence",
+        "ordinal": 7,
+        "type_info": "Integer"
+      }
+    ],
+    "parameters": {
+      "Right": 1
+    },
+    "nullable": [
+      false,
+      false,
+      false,
+      false,
+      false,
+      false,
+      false,
+      false
+    ]
+  },
+  "hash": "5c53579fa431b6e184faf94eedb8229360ba78f2607d25e7e2ee5db5c759a5a3"
+}
diff --git a/.sqlx/query-7e816ede017bc2635c11ab72b18b7af92ac1f1faed9df41df90f57cb596cfe7c.json b/.sqlx/query-7e816ede017bc2635c11ab72b18b7af92ac1f1faed9df41df90f57cb596cfe7c.json
deleted file mode 100644
index f546438..0000000
--- a/.sqlx/query-7e816ede017bc2635c11ab72b18b7af92ac1f1faed9df41df90f57cb596cfe7c.json
+++ /dev/null
@@ -1,74 +0,0 @@
-{
-  "db_name": "SQLite",
-  "query": "\n\t\t\t\tselect\n\t\t\t\t\tmessage.id as \"id: message::Id\",\n                    channel.id as \"channel_id: channel::Id\",\n                    channel.name as \"channel_name\",\n                    channel.created_at as \"channel_created_at: DateTime\",\n                    channel.created_sequence as \"channel_created_sequence: Sequence\",\n\t\t\t\t\tsender.id as \"sender_id: login::Id\",\n\t\t\t\t\tsender.name as sender_name,\n                    message.sent_at as \"sent_at: DateTime\",\n                    message.sent_sequence as \"sent_sequence: Sequence\",\n                    message.body\n\t\t\t\tfrom message\n                    join channel on message.channel = channel.id\n\t\t\t\t\tjoin login as sender on message.sender = sender.id\n\t\t\t\twhere coalesce(message.sent_sequence > $1, true)\n\t\t\t\torder by sent_sequence asc\n\t\t\t",
-  "describe": {
-    "columns": [
-      {
-        "name": "id: message::Id",
-        "ordinal": 0,
-        "type_info": "Text"
-      },
-      {
-        "name": "channel_id: channel::Id",
-        "ordinal": 1,
-        "type_info": "Text"
-      },
-      {
-        "name": "channel_name",
-        "ordinal": 2,
-        "type_info": "Text"
-      },
-      {
-        "name": "channel_created_at: DateTime",
-        "ordinal": 3,
-        "type_info": "Text"
-      },
-      {
-        "name": "channel_created_sequence: Sequence",
-        "ordinal": 4,
-        "type_info": "Integer"
-      },
-      {
-        "name": "sender_id: login::Id",
-        "ordinal": 5,
-        "type_info": "Text"
-      },
-      {
-        "name": "sender_name",
-        "ordinal": 6,
-        "type_info": "Text"
-      },
-      {
-        "name": "sent_at: DateTime",
-        "ordinal": 7,
-        "type_info": "Text"
-      },
-      {
-        "name": "sent_sequence: Sequence",
-        "ordinal": 8,
-        "type_info": "Integer"
-      },
-      {
-        "name": "body",
-        "ordinal": 9,
-        "type_info": "Text"
-      }
-    ],
-    "parameters": {
-      "Right": 1
-    },
-    "nullable": [
-      false,
-      false,
-      false,
-      false,
-      false,
-      false,
-      false,
-      false,
-      false,
-      false
-    ]
-  },
-  "hash": "7e816ede017bc2635c11ab72b18b7af92ac1f1faed9df41df90f57cb596cfe7c"
-}
diff --git a/.sqlx/query-b7e05e2b2eb5484c954bcedf5de8c7d9ad11bb09a0d0d243181d97c79d771071.json b/.sqlx/query-b7e05e2b2eb5484c954bcedf5de8c7d9ad11bb09a0d0d243181d97c79d771071.json
new file mode 100644
index 0000000..b82727f
--- /dev/null
+++ b/.sqlx/query-b7e05e2b2eb5484c954bcedf5de8c7d9ad11bb09a0d0d243181d97c79d771071.json
@@ -0,0 +1,20 @@
+{
+  "db_name": "SQLite",
+  "query": "\n                select\n                    channel.id as \"id: Id\"\n                from channel\n                    left join message\n                where created_at < $1\n                    and message.id is null\n            ",
+  "describe": {
+    "columns": [
+      {
+        "name": "id: Id",
+        "ordinal": 0,
+        "type_info": "Text"
+      }
+    ],
+    "parameters": {
+      "Right": 1
+    },
+    "nullable": [
+      false
+    ]
+  },
+  "hash": "b7e05e2b2eb5484c954bcedf5de8c7d9ad11bb09a0d0d243181d97c79d771071"
+}
diff --git a/.sqlx/query-d382215ac9e9d8d2c9b5eb6f1c2744bdb7a93c39ebcf15087c89bba6be71f7cb.json b/.sqlx/query-d382215ac9e9d8d2c9b5eb6f1c2744bdb7a93c39ebcf15087c89bba6be71f7cb.json
deleted file mode 100644
index 1d448d4..0000000
--- a/.sqlx/query-d382215ac9e9d8d2c9b5eb6f1c2744bdb7a93c39ebcf15087c89bba6be71f7cb.json
+++ /dev/null
@@ -1,20 +0,0 @@
-{
-  "db_name": "SQLite",
-  "query": "\n                delete from channel\n                where id = $1\n                returning 1 as \"row: i64\"\n            ",
-  "describe": {
-    "columns": [
-      {
-        "name": "row: i64",
-        "ordinal": 0,
-        "type_info": "Null"
-      }
-    ],
-    "parameters": {
-      "Right": 1
-    },
-    "nullable": [
-      null
-    ]
-  },
-  "hash": "d382215ac9e9d8d2c9b5eb6f1c2744bdb7a93c39ebcf15087c89bba6be71f7cb"
-}
diff --git a/.sqlx/query-e93702ad922c7ce802499e99e837106c799e84015425286b79f42e4001d8a4c7.json b/.sqlx/query-e93702ad922c7ce802499e99e837106c799e84015425286b79f42e4001d8a4c7.json
new file mode 100644
index 0000000..288a657
--- /dev/null
+++ b/.sqlx/query-e93702ad922c7ce802499e99e837106c799e84015425286b79f42e4001d8a4c7.json
@@ -0,0 +1,62 @@
+{
+  "db_name": "SQLite",
+  "query": "\n                select\n                    channel.id as \"channel_id: channel::Id\",\n                    channel.name as \"channel_name\",\n                    sender.id as \"sender_id: login::Id\",\n                    sender.name as \"sender_name\",\n                    message.id as \"id: Id\",\n                    message.body,\n                    sent_at as \"sent_at: DateTime\",\n                    sent_sequence as \"sent_sequence: Sequence\"\n                from message\n                    join channel on message.channel = channel.id\n                    join login as sender on message.sender = sender.id\n                where message.id = $1\n                    and message.channel = $2\n            ",
+  "describe": {
+    "columns": [
+      {
+        "name": "channel_id: channel::Id",
+        "ordinal": 0,
+        "type_info": "Text"
+      },
+      {
+        "name": "channel_name",
+        "ordinal": 1,
+        "type_info": "Text"
+      },
+      {
+        "name": "sender_id: login::Id",
+        "ordinal": 2,
+        "type_info": "Text"
+      },
+      {
+        "name": "sender_name",
+        "ordinal": 3,
+        "type_info": "Text"
+      },
+      {
+        "name": "id: Id",
+        "ordinal": 4,
+        "type_info": "Text"
+      },
+      {
+        "name": "body",
+        "ordinal": 5,
+        "type_info": "Text"
+      },
+      {
+        "name": "sent_at: DateTime",
+        "ordinal": 6,
+        "type_info": "Text"
+      },
+      {
+        "name": "sent_sequence: Sequence",
+        "ordinal": 7,
+        "type_info": "Integer"
+      }
+    ],
+    "parameters": {
+      "Right": 2
+    },
+    "nullable": [
+      false,
+      false,
+      false,
+      false,
+      false,
+      false,
+      false,
+      false
+    ]
+  },
+  "hash": "e93702ad922c7ce802499e99e837106c799e84015425286b79f42e4001d8a4c7"
+}