import { describe, expect, test } from "bun:test"

import { promises as fs } from "fs"

import path from "path"

import os from "os"

import {

CODEX_AGENTS_BLOCK_END,

CODEX_AGENTS_BLOCK_START,

ensureCodexAgentsFile,

} from "../src/utils/codex-agents"

async function readFile(filePath: string): Promise<string> {

return fs.readFile(filePath, "utf8")

}

describe("ensureCodexAgentsFile", () => {

test("creates AGENTS.md with managed block when missing", async () => {

const tempRoot = await fs.mkdtemp(path.join(os.tmpdir(), "codex-agents-"))

await ensureCodexAgentsFile(tempRoot)

const agentsPath = path.join(tempRoot, "AGENTS.md")

const content = await readFile(agentsPath)

expect(content).toContain(CODEX_AGENTS_BLOCK_START)

expect(content).toContain("Tool mapping")

expect(content).toContain(CODEX_AGENTS_BLOCK_END)

})

test("appends block without touching existing content", async () => {

const tempRoot = await fs.mkdtemp(path.join(os.tmpdir(), "codex-agents-existing-"))

const agentsPath = path.join(tempRoot, "AGENTS.md")

await fs.writeFile(agentsPath, "# My Rules\n\nKeep this.")

await ensureCodexAgentsFile(tempRoot)

const content = await readFile(agentsPath)

expect(content).toContain("# My Rules")

expect(content).toContain("Keep this.")

expect(content).toContain(CODEX_AGENTS_BLOCK_START)

expect(content).toContain(CODEX_AGENTS_BLOCK_END)

})

test("replaces only the managed block when present", async () => {

const tempRoot = await fs.mkdtemp(path.join(os.tmpdir(), "codex-agents-update-"))

const agentsPath = path.join(tempRoot, "AGENTS.md")

const seed = [

"Intro text",

CODEX_AGENTS_BLOCK_START,

"old content",

CODEX_AGENTS_BLOCK_END,

"Footer text",

].join("\n")

await fs.writeFile(agentsPath, seed)

await ensureCodexAgentsFile(tempRoot)

const content = await readFile(agentsPath)

expect(content).toContain("Intro text")

expect(content).toContain("Footer text")

expect(content).not.toContain("old content")

expect(content).toContain(CODEX_AGENTS_BLOCK_START)

expect(content).toContain(CODEX_AGENTS_BLOCK_END)

})

})