1 files changed, 94 insertions, 0 deletions

diff --git a/packages/turbo-codemod/src/runner/FileTransform.ts b/packages/turbo-codemod/src/runner/FileTransform.ts
new file mode 100644
index 0000000..3b23f73
--- /dev/null
+++ b/packages/turbo-codemod/src/runner/FileTransform.ts
@@ -0,0 +1,94 @@
+import chalk from "chalk";
+import { diffLines, Change, diffJson } from "diff";
+import fs from "fs-extra";
+import os from "os";
+import path from "path";
+
+import type { FileTransformArgs, LogFileArgs } from "./types";
+
+export default class FileTransform {
+  filePath: string;
+  rootPath: string;
+  before: string | object;
+  after?: string | object;
+  error?: Error;
+  changes: Array<Change> = [];
+
+  constructor(args: FileTransformArgs) {
+    this.filePath = args.filePath;
+    this.rootPath = args.rootPath;
+    this.after = args.after;
+    this.error = args.error;
+
+    // load original file for comparison
+    if (args.before === undefined) {
+      try {
+        if (path.extname(args.filePath) === ".json") {
+          this.before = fs.readJsonSync(args.filePath);
+        } else {
+          this.before = fs.readFileSync(args.filePath);
+        }
+      } catch (err) {
+        this.before = "";
+      }
+    } else if (args.before === null) {
+      this.before = "";
+    } else {
+      this.before = args.before;
+    }
+
+    // determine diff
+    if (args.after) {
+      if (typeof this.before === "object" || typeof args.after === "object") {
+        this.changes = diffJson(this.before, args.after);
+      } else {
+        this.changes = diffLines(this.before, args.after);
+      }
+    } else {
+      this.changes = [];
+    }
+  }
+
+  fileName(): string {
+    return path.relative(this.rootPath, this.filePath);
+  }
+
+  write(): void {
+    if (this.after) {
+      if (typeof this.after === "object") {
+        fs.writeJsonSync(this.filePath, this.after, { spaces: 2 });
+      } else {
+        fs.writeFileSync(this.filePath, this.after);
+      }
+    }
+  }
+
+  additions(): number {
+    return this.changes.filter((c) => c.added).length;
+  }
+
+  deletions(): number {
+    return this.changes.filter((c) => c.removed).length;
+  }
+
+  hasChanges(): boolean {
+    return this.additions() > 0 || this.deletions() > 0;
+  }
+
+  log(args: LogFileArgs): void {
+    if (args.diff) {
+      this.changes.forEach((part) => {
+        if (part.added) {
+          process.stdout.write(chalk.green(part.value));
+        } else if (part.removed) {
+          process.stdout.write(chalk.red(part.value));
+        } else {
+          process.stdout.write(chalk.dim(part.value));
+        }
+      });
+      console.log(os.EOL);
+    } else {
+      console.log(this.after);
+    }
+  }
+}