From 8a5b585ba57f712dd7ad2372da3355e3ad9628c4 Mon Sep 17 00:00:00 2001
From: Ned Palacios <npdoesmc@gmail.com>
Date: Wed, 29 Nov 2023 19:30:12 +0800
Subject: [PATCH] fix: make support for Java.ParseEndOfFileError work

---
 .../java/parse_end_of_file_error.go           | 59 ++++++++++++++++++-
 .../parse_end_of_file_error/test.txt          | 29 +++++----
 2 files changed, 70 insertions(+), 18 deletions(-)

diff --git a/error_templates/java/parse_end_of_file_error.go b/error_templates/java/parse_end_of_file_error.go
index 900d033..94de308 100644
--- a/error_templates/java/parse_end_of_file_error.go
+++ b/error_templates/java/parse_end_of_file_error.go
@@ -2,10 +2,12 @@ package java
 
 import (
 	lib "github.com/nedpals/errgoengine"
+	sitter "github.com/smacker/go-tree-sitter"
 )
 
 type parseEofErrorCtx struct {
-	missingSymStack []string
+	missingSymStack  []string
+	missingCharacter string
 }
 
 var ParseEndOfFileError = lib.ErrorTemplate{
@@ -13,12 +15,63 @@ var ParseEndOfFileError = lib.ErrorTemplate{
 	Pattern:           comptimeErrorPattern("reached end of file while parsing"),
 	StackTracePattern: comptimeStackTracePattern,
 	OnAnalyzeErrorFn: func(cd *lib.ContextData, m *lib.MainError) {
+		ctx := parseEofErrorCtx{}
 
+		// traverse the tree and get the nearest "missing" node
+		rootNode := m.Document.Tree.RootNode()
+		cursor := sitter.NewTreeCursor(rootNode)
+		rawNearestMissingNode := nearestMissingNodeFromPos(cursor, m.ErrorNode.StartPos)
+		nearestMissingNode := lib.WrapNode(m.Document, rawNearestMissingNode)
+		m.Nearest = nearestMissingNode
+		nearestStr := m.Nearest.String()
+		prefix := "(MISSING \""
+		ctx.missingCharacter = nearestStr[len(prefix) : len(prefix)+1]
+		m.Context = ctx
 	},
 	OnGenExplainFn: func(cd *lib.ContextData, gen *lib.ExplainGenerator) {
-		gen.Add("The compiler was not able to compile your program because one or more closing brackets were missing in the program.")
+		gen.Add("This error occurs when the compiler expects more code but encounters the end of the file.")
 	},
 	OnGenBugFixFn: func(cd *lib.ContextData, gen *lib.BugFixGenerator) {
-		// TODO:
+		ctx := cd.MainError.Context.(parseEofErrorCtx)
+
+		gen.Add("Complete the code", func(s *lib.BugFixSuggestion) {
+			endPos := cd.MainError.Nearest.EndPosition()
+
+			s.AddStep("Add the missing `%s` in line %d", ctx.missingCharacter, endPos.Line+1).
+				AddFix(lib.FixSuggestion{
+					NewText:       "\n" + ctx.missingCharacter,
+					StartPosition: endPos,
+					EndPosition:   endPos,
+				})
+		})
 	},
 }
+
+func nearestMissingNodeFromPos(cursor *sitter.TreeCursor, pos lib.Position) *sitter.Node {
+	defer cursor.GoToParent()
+
+	// hope it executes to avoid stack overflow
+	if !cursor.GoToFirstChild() {
+		return nil
+	}
+
+	for {
+		currentNode := cursor.CurrentNode()
+		pointA := currentNode.StartPoint()
+		pointB := currentNode.EndPoint()
+
+		if uint32(pos.Line) >= pointA.Row+1 && uint32(pos.Line) <= pointB.Row+1 {
+			if currentNode.IsMissing() {
+				return currentNode
+			} else if currentNode.ChildCount() != 0 {
+				if gotNode := nearestMissingNodeFromPos(cursor, pos); gotNode != nil {
+					return gotNode
+				}
+			}
+		}
+
+		if !cursor.GoToNextSibling() {
+			return nil
+		}
+	}
+}
diff --git a/error_templates/java/test_files/parse_end_of_file_error/test.txt b/error_templates/java/test_files/parse_end_of_file_error/test.txt
index e178c85..f88fc8d 100644
--- a/error_templates/java/test_files/parse_end_of_file_error/test.txt
+++ b/error_templates/java/test_files/parse_end_of_file_error/test.txt
@@ -8,22 +8,21 @@ EOF.java:4: error: reached end of file while parsing
 template: "Java.ParseEndOfFileError"
 ---
 # ParseEndOfFileError
-This error indicates that the compiler reached the end of the file unexpectedly while it was expecting something more in the code.
-
-## Explanation local to the file
-The error occurred due to an incomplete block of code in the `EOF.java` file. The compiler was expecting more code or the completion of a block but encountered the end of the file prematurely.
+This error occurs when the compiler expects more code but encounters the end of the file.
+```
+        System.out.println("This is a sample program.");
+    }
+     ^
 
+```
 ## Steps to fix
-1. Ensure that all opening braces `{` have their corresponding closing braces `}` to complete the code blocks.
-
+### Complete the code
+Add the missing `}` in line 4
 ```diff
-   public class EOF {
-       public static void main(String[] args) {
-           System.out.println("This is a sample program.");
-+      }
-   }
-```
+    public static void main(String[] args) {
+        System.out.println("This is a sample program.");
+-     }
++     }
++ }
 
-This fix completes the `main` method by adding the closing curly brace `}`.
-
-2. If the error persists, check the entire file for missing or misplaced braces, ensuring they are correctly matched and closed. Double-check that each opening brace has a corresponding closing brace to resolve this issue.
+```