From ec973e82d367735017dbcda32ce2df0b95aa853f Mon Sep 17 00:00:00 2001
From: Ned Palacios <npdoesmc@gmail.com>
Date: Wed, 13 Dec 2023 00:52:56 +0800
Subject: [PATCH] feat: support for Java.NotAStatementError error

---
 error_templates/java/java.go                  |  1 +
 error_templates/java/not_a_statement_error.go | 54 +++++++++++++++++++
 .../not_a_statement_error/NotAStatement.java  |  5 ++
 .../test_files/not_a_statement_error/test.txt | 42 +++++++++++++++
 4 files changed, 102 insertions(+)
 create mode 100644 error_templates/java/not_a_statement_error.go
 create mode 100644 error_templates/java/test_files/not_a_statement_error/NotAStatement.java

diff --git a/error_templates/java/java.go b/error_templates/java/java.go
index 7a25715..453416c 100644
--- a/error_templates/java/java.go
+++ b/error_templates/java/java.go
@@ -24,6 +24,7 @@ func LoadErrorTemplates(errorTemplates *lib.ErrorTemplates) {
 	errorTemplates.MustAdd(java.Language, UnclosedCharacterLiteralError)
 	errorTemplates.MustAdd(java.Language, OperatorCannotBeAppliedError)
 	errorTemplates.MustAdd(java.Language, PrecisionLossError)
+	errorTemplates.MustAdd(java.Language, NotAStatementError)
 }
 
 func runtimeErrorPattern(errorName string, pattern string) string {
diff --git a/error_templates/java/not_a_statement_error.go b/error_templates/java/not_a_statement_error.go
new file mode 100644
index 0000000..7ee0fd7
--- /dev/null
+++ b/error_templates/java/not_a_statement_error.go
@@ -0,0 +1,54 @@
+package java
+
+import (
+	"fmt"
+	"regexp"
+	"strings"
+
+	lib "github.com/nedpals/errgoengine"
+)
+
+func generateVarName(inputString string) string {
+	reg := regexp.MustCompile("[^a-zA-Z0-9_]")
+	processedString := reg.ReplaceAllString(inputString, "")
+	return strings.TrimSpace(processedString)
+}
+
+var NotAStatementError = lib.ErrorTemplate{
+	Name:              "NotAStatementError",
+	Pattern:           comptimeErrorPattern(`not a statement`),
+	StackTracePattern: comptimeStackTracePattern,
+	OnAnalyzeErrorFn: func(cd *lib.ContextData, m *lib.MainError) {
+		if m.Nearest.Type() == "expression_statement" {
+			m.Nearest = m.Nearest.NamedChild(0)
+		}
+	},
+	OnGenExplainFn: func(cd *lib.ContextData, gen *lib.ExplainGenerator) {
+		gen.Add("This error occurs when a line of code is written that is not a valid statement.")
+	},
+	OnGenBugFixFn: func(cd *lib.ContextData, gen *lib.BugFixGenerator) {
+		nodeType := cd.Analyzer.AnalyzeNode(cd.MainError.Nearest)
+
+		gen.Add(fmt.Sprintf("Convert the `%s` to a statement", nodeType.Name()), func(s *lib.BugFixSuggestion) {
+			s.AddStep(
+				"If you intended to use the `%s` as a statement, you can print it or use it in a valid statement.",
+				nodeType.Name(),
+			).AddFix(lib.FixSuggestion{
+				NewText:       fmt.Sprintf("System.out.println(%s)", cd.MainError.Nearest.Text()),
+				StartPosition: cd.MainError.Nearest.StartPosition(),
+				EndPosition:   cd.MainError.Nearest.EndPosition(),
+				Description:   "This change makes the string part of a valid statement by printing it to the console.",
+			})
+		})
+
+		gen.Add(fmt.Sprintf("Assign the `%s` to a variable", nodeType.Name()), func(s *lib.BugFixSuggestion) {
+			s.AddStep("Alternatively, you can assign the `%s` to a variable to make it a valid statement.", nodeType.Name()).
+				AddFix(lib.FixSuggestion{
+					NewText:       fmt.Sprintf("%s %s = %s", nodeType.Name(), generateVarName(cd.MainError.Nearest.Text()), cd.MainError.Nearest.Text()),
+					StartPosition: cd.MainError.Nearest.StartPosition(),
+					EndPosition:   cd.MainError.Nearest.EndPosition(),
+					Description:   "This way, the string is now part of a statement and can be used later in your code.",
+				})
+		})
+	},
+}
diff --git a/error_templates/java/test_files/not_a_statement_error/NotAStatement.java b/error_templates/java/test_files/not_a_statement_error/NotAStatement.java
new file mode 100644
index 0000000..c68dc8b
--- /dev/null
+++ b/error_templates/java/test_files/not_a_statement_error/NotAStatement.java
@@ -0,0 +1,5 @@
+public class NotAStatement {
+    public static void main(String[] args) {
+        "test";
+    }
+}
diff --git a/error_templates/java/test_files/not_a_statement_error/test.txt b/error_templates/java/test_files/not_a_statement_error/test.txt
index e69de29..d868bf0 100644
--- a/error_templates/java/test_files/not_a_statement_error/test.txt
+++ b/error_templates/java/test_files/not_a_statement_error/test.txt
@@ -0,0 +1,42 @@
+template: "Java.NotAStatementError"
+---
+NotAStatement.java:3: error: not a statement
+        "test";
+        ^
+1 error
+===
+template: "Java.NotAStatementError"
+---
+# NotAStatementError
+This error occurs when a line of code is written that is not a valid statement.
+```
+    public static void main(String[] args) {
+        "test";
+        ^^^^^^
+    }
+}
+```
+## Steps to fix
+### 1. Convert the `String` to a statement
+If you intended to use the `String` as a statement, you can print it or use it in a valid statement.
+```diff
+public class NotAStatement {
+    public static void main(String[] args) {
+-         "test";
++         System.out.println("test");
+    }
+}
+```
+This change makes the string part of a valid statement by printing it to the console.
+
+### 2. Assign the `String` to a variable
+Alternatively, you can assign the `String` to a variable to make it a valid statement.
+```diff
+public class NotAStatement {
+    public static void main(String[] args) {
+-         "test";
++         String test = "test";
+    }
+}
+```
+This way, the string is now part of a statement and can be used later in your code.