changed default user agent to "Firefox" to fix google/youtube pages not working

README.md

@@ -65,6 +65,7 @@ Here are the details of each parameter used in the patching system:
   1. **`standard`:** Standard patching type that follows the `+` (add) and `-` (remove) syntax.
 
      - Used for general file modifications.
+     - Supports multi-line block matching: the entire `-` block must be present to be replaced by the `+` block.
      - **Example:**
        ```patch
        i: /browser/branding/official/configure.sh
@@ -73,6 +74,21 @@ Here are the details of each parameter used in the patching system:
        -MOZ_APP_DISPLAYNAME=Firefox
        +MOZ_APP_DISPLAYNAME=Spitfire
        ```
+      - **Multi-line example:**
+       ```patch
+        -project_flag(
+        -    env="MOZ_APP_UA_NAME",
+        -    default="",
+        -    nargs=1,
+        -    help="application name in the User Agent string",
+        -)
+        +project_flag(
+        +    env="MOZ_APP_UA_NAME",
+        +    default="Firefox",
+        +    nargs=1,
+        +    help="application name in the User Agent string",
+        +)
+      ```
 
      Note: *Type will fallback to t:standard when no type is specified.*
   2. **`pref`:** Indicates that the patch is modifying preference settings (e.g., Firefox `prefs.js`).

pre-compile-patches/user-agent.patch

@@ -0,0 +1,16 @@
+t: standard
+i: /toolkit/moz.configure
+o: /toolkit/moz.configure
+
+-project_flag(
+-    env="MOZ_APP_UA_NAME",
+-    default="",
+-    nargs=1,
+-    help="Application name in the User Agent string",
+-)
++project_flag(
++    env="MOZ_APP_UA_NAME",
++    default="Firefox",
++    nargs=1,
++    help="application name in the User Agent string",
++)

standard.go

@@ -1,102 +1,75 @@
 package main
 
 import (
-	"bufio"
 	"fmt"
 	"os"
 	"strings"
 )
 
 // applyStandardModifications handles `standard` type patches
-func applyStandardModifications(targetFilePath string, modifications []string) error {
-	fmt.Printf("Applying standard modifications to file: %s\n", targetFilePath)
-
-	// Open the target file for reading and writing
-	file, err := os.OpenFile(targetFilePath, os.O_RDWR, 0644)
+func applyStandardModifications(filePath string, modifications []string) error {
+	contentBytes, err := os.ReadFile(filePath)
 	if err != nil {
-		return fmt.Errorf("failed to open target file '%s': %v", targetFilePath, err)
+		return fmt.Errorf("failed to read file: %v", err)
 	}
-	defer file.Close()
+	lines := strings.Split(string(contentBytes), "\n")
 
-	scanner := bufio.NewScanner(file)
-	targetLines := []string{}
-
-	// Read all lines from the target file
-	for scanner.Scan() {
-		targetLines = append(targetLines, scanner.Text())
-	}
-	if err := scanner.Err(); err != nil {
-		return fmt.Errorf("failed to read target file '%s': %v", targetFilePath, err)
+	var delBlock []string
+	var addBlock []string
+	var patchBlocks []struct {
+		del []string
+		add []string
 	}
 
-	modifiedLines := map[string]bool{}
-	modMap := parseModifications(modifications)
+	// Group lines into delete and add blocks
+	for _, line := range modifications {
+		if strings.HasPrefix(line, "-") {
+			delBlock = append(delBlock, strings.TrimPrefix(line, "-"))
+		} else if strings.HasPrefix(line, "+") {
+			addBlock = append(addBlock, strings.TrimPrefix(line, "+"))
+		} else if line == "" && len(delBlock) > 0 {
+			patchBlocks = append(patchBlocks, struct {
+				del []string
+				add []string
+			}{append([]string{}, delBlock...), append([]string{}, addBlock...)})
+			delBlock = nil
+			addBlock = nil
+		}
+	}
+	if len(delBlock) > 0 || len(addBlock) > 0 {
+		patchBlocks = append(patchBlocks, struct {
+			del []string
+			add []string
+		}{delBlock, addBlock})
+	}
 
-	var updatedContent strings.Builder
-
-	// Apply modifications to the target lines
-	for _, line := range targetLines {
-		lineModified := false
-
-		for key, mod := range modMap {
-			if strings.Contains(line, key) && !modifiedLines[key] {
-				fmt.Printf("Replacing line in file '%s': %s -> %s\n", targetFilePath, line, mod)
-				updatedContent.WriteString(mod + "\n")
-				modifiedLines[key] = true
-				lineModified = true
+	// Apply each block
+	for _, patch := range patchBlocks {
+		matchIndex := -1
+		for i := 0; i <= len(lines)-len(patch.del); i++ {
+			matched := true
+			for j := range patch.del {
+				if strings.TrimSpace(lines[i+j]) != strings.TrimSpace(patch.del[j]) {
+					matched = false
+					break
+				}
+			}
+			if matched {
+				matchIndex = i
 				break
 			}
 		}
-
-		// Write the original line if no modification matches
-		if !lineModified {
-			updatedContent.WriteString(line + "\n")
+		if matchIndex == -1 {
+			return fmt.Errorf("patch block not found in file: %v", patch.del)
 		}
+
+		// Replace matched block
+		newLines := append([]string{}, lines[:matchIndex]...)
+		newLines = append(newLines, patch.add...)
+		newLines = append(newLines, lines[matchIndex+len(patch.del):]...)
+		lines = newLines
 	}
 
-	// Append any remaining modifications that were not applied
-	for key, mod := range modMap {
-		if !modifiedLines[key] {
-			fmt.Printf("Adding new line to file '%s': %s\n", targetFilePath, mod)
-			updatedContent.WriteString(mod + "\n")
-		}
-	}
-
-	// Truncate and rewrite the file with updated content
-	if err := file.Truncate(0); err != nil {
-		return fmt.Errorf("failed to truncate file '%s': %v", targetFilePath, err)
-	}
-	if _, err := file.Seek(0, 0); err != nil {
-		return fmt.Errorf("failed to reset file pointer for '%s': %v", targetFilePath, err)
-	}
-	if _, err := file.WriteString(updatedContent.String()); err != nil {
-		return fmt.Errorf("failed to write updated content to file '%s': %v", targetFilePath, err)
-	}
-
-	fmt.Printf("Standard modifications successfully applied to file: %s\n", targetFilePath)
-	return nil
-}
-
-// parseModifications converts a list of modification strings into a map for processing
-func parseModifications(modifications []string) map[string]string {
-	modMap := map[string]string{}
-	for _, mod := range modifications {
-		if strings.HasPrefix(mod, "+") || strings.HasPrefix(mod, "-") {
-			trimmed := strings.TrimSpace(strings.TrimPrefix(mod, "+"))
-			trimmed = strings.TrimPrefix(trimmed, "-")
-			key := extractKey(trimmed)
-			modMap[key] = trimmed
-		}
-	}
-	return modMap
-}
-
-// extractKey extracts the key from a modification string
-func extractKey(line string) string {
-	start := strings.Index(line, "(")
-	end := strings.LastIndex(line, ")")
-	if start > 0 && end > start {
-		return strings.TrimSpace(line[start+1 : end])
-	}
-	return line // Fallback: return the full line
+	// Write updated file
+	return os.WriteFile(filePath, []byte(strings.Join(lines, "\n")), 0644)
 }