From 8c4423fcd32336f8d61fac7aa1d7098329aac6e9 Mon Sep 17 00:00:00 2001
From: Mitchell Hanberg <mitch@mitchellhanberg.com>
Date: Sat, 5 Aug 2023 11:21:59 -0400
Subject: [PATCH] feat: go to definition when aliases modules

---
 lib/next_ls.ex                           |  7 ++-
 lib/next_ls/definition.ex                | 68 +++++++++++++++++-------
 lib/next_ls/runtime/sidecar.ex           |  4 ++
 priv/monkey/_next_ls_private_compiler.ex | 11 +++-
 4 files changed, 68 insertions(+), 22 deletions(-)

diff --git a/lib/next_ls.ex b/lib/next_ls.ex
index 4ce70445..cf040803 100644
--- a/lib/next_ls.ex
+++ b/lib/next_ls.ex
@@ -129,7 +129,12 @@ defmodule NextLS do
     result =
       dispatch(lsp.assigns.registry, :databases, fn entries ->
         for {pid, _} <- entries do
-          case Definition.fetch(URI.parse(uri).path, {position.line + 1, position.character + 1}, pid) do
+          case Definition.fetch(
+                 URI.parse(uri).path,
+                 {position.line + 1, position.character + 1},
+                 pid,
+                 Enum.join(lsp.assigns.documents[uri], "\n")
+               ) do
             nil ->
               nil
 
diff --git a/lib/next_ls/definition.ex b/lib/next_ls/definition.ex
index 4dc304f0..e86af354 100644
--- a/lib/next_ls/definition.ex
+++ b/lib/next_ls/definition.ex
@@ -4,24 +4,16 @@ defmodule NextLS.Definition do
 
   alias NextLS.DB
 
-  def fetch(file, {line, col}, db) do
-    with [[_pk, identifier, _arity, _file, type, module, _start_l, _start_c, _end_l, _end_c | _]] <-
-           DB.query(
-             db,
-             ~Q"""
-             SELECT
-                 *
-             FROM
-                 'references' AS refs
-             WHERE
-                 refs.file = ?
-                 AND ? BETWEEN refs.start_line AND refs.end_line
-                 AND ? BETWEEN refs.start_column AND refs.end_column
-             ORDER BY refs.id asc
-             LIMIT 1;
-             """,
-             [file, line, col]
-           ) do
+  def fetch(file, {line, col}, db, text) do
+    reference =
+      with nil <- fetch_from_db(db, {file, line, col}),
+           nil <- fetch_from_context(text, {line, col}) do
+        nil
+      end
+
+    dbg(reference)
+
+    with %{identifier: identifier, type: type, module: module} <- reference do
       query =
         ~Q"""
         SELECT
@@ -50,7 +42,45 @@ defmodule NextLS.Definition do
       else
         nil
       end
-    else
+    end
+  end
+
+  defp fetch_from_db(db, {file, line, col}) do
+    rows =
+      DB.query(
+        db,
+        ~Q"""
+        SELECT
+            *
+        FROM
+            'references' AS refs
+        WHERE
+            refs.file = ?
+            AND refs.start_line <= ?
+            AND ? <= refs.end_line
+            AND refs.start_column <= ?
+            AND ? <= refs.end_column
+        ORDER BY refs.id asc
+        LIMIT 1;
+        """,
+        [file, line, line, col, col]
+      )
+
+    case rows do
+      [[_pk, identifier, _arity, _file, type, module, _start_l, _start_c, _end_l, _end_c | _]] ->
+        %{identifier: identifier, type: type, module: module}
+
+      [] ->
+        nil
+    end
+  end
+
+  defp fetch_from_context(text, {line, col}) do
+    case Code.Fragment.surround_context(text, {line, col}) do
+      %{context: {:alias, alias}} ->
+        module = to_string(alias)
+        %{identifier: module, type: "alias", module: module}
+
       _ ->
         nil
     end
diff --git a/lib/next_ls/runtime/sidecar.ex b/lib/next_ls/runtime/sidecar.ex
index 64ec9626..b6b88ad2 100644
--- a/lib/next_ls/runtime/sidecar.ex
+++ b/lib/next_ls/runtime/sidecar.ex
@@ -28,7 +28,11 @@ defmodule NextLS.Runtime.Sidecar do
 
   def handle_info({{:tracer, :start}, filename}, state) do
     DB.clean_references(state.db, filename)
+    {:noreply, state}
+  end
 
+  def handle_info({{:tracer, :dbg}, payload}, state) do
+    dbg(payload)
     {:noreply, state}
   end
 end
diff --git a/priv/monkey/_next_ls_private_compiler.ex b/priv/monkey/_next_ls_private_compiler.ex
index e382a96e..fe784e47 100644
--- a/priv/monkey/_next_ls_private_compiler.ex
+++ b/priv/monkey/_next_ls_private_compiler.ex
@@ -84,7 +84,8 @@ defmodule NextLSPrivate.Tracer do
     :ok
   end
 
-  def trace({type, meta, module, func, arity}, env) when type in [:remote_function, :remote_macro, :imported_macro] do
+  def trace({type, meta, module, func, arity} = it, env)
+      when type in [:remote_function, :remote_macro, :imported_macro] do
     parent = parent_pid()
 
     if type == :remote_macro && meta[:closing][:line] != meta[:line] do
@@ -111,7 +112,7 @@ defmodule NextLSPrivate.Tracer do
     :ok
   end
 
-  def trace({type, meta, func, arity}, env) when type in [:local_function, :local_macro] do
+  def trace({type, meta, func, arity} = it, env) when type in [:local_function, :local_macro] do
     parent = parent_pid()
 
     Process.send(
@@ -163,6 +164,12 @@ defmodule NextLSPrivate.Tracer do
     :ok
   end
 
+  def trace(it, env) do
+    parent = parent_pid()
+    Process.send(parent, {{:tracer, :dbg}, {it, env.aliases}}, [])
+    :ok
+  end
+
   def trace(_event, _env) do
     :ok
   end