lazy load formatters

packages/opencode/src/file/index.ts

@@ -0,0 +1,13 @@
+import { z } from "zod"
+import { Bus } from "../bus"
+
+export namespace File {
+  export const Event = {
+    Edited: Bus.event(
+      "file.edited",
+      z.object({
+        file: z.string(),
+      }),
+    ),
+  }
+}

packages/opencode/src/file/time.ts

@@ -0,0 +1,38 @@
+import { App } from "../app/app"
+
+export namespace FileTime {
+  export const state = App.state("tool.filetimes", () => {
+    const read: {
+      [sessionID: string]: {
+        [path: string]: Date | undefined
+      }
+    } = {}
+    return {
+      read,
+    }
+  })
+
+  export function read(sessionID: string, file: string) {
+    const { read } = state()
+    read[sessionID] = read[sessionID] || {}
+    read[sessionID][file] = new Date()
+  }
+
+  export function get(sessionID: string, file: string) {
+    return state().read[sessionID]?.[file]
+  }
+
+  export async function assert(sessionID: string, filepath: string) {
+    const time = get(sessionID, filepath)
+    if (!time)
+      throw new Error(
+        `You must read the file ${filepath} before overwriting it. Use the Read tool first`,
+      )
+    const stats = await Bun.file(filepath).stat()
+    if (stats.mtime.getTime() > time.getTime()) {
+      throw new Error(
+        `File ${filepath} has been modified since it was last read.\nLast modification: ${stats.mtime.toISOString()}\nLast read: ${time.toISOString()}\n\nPlease read the file again before modifying it.`,
+      )
+    }
+  }
+}