import test from 'node:test';
import assert from 'node:assert/strict';
import fs from 'node:fs';
import { join } from 'node:path';
import { tmpdir } from 'node:os';
import { connect } from 'node:net';
import * as runner from '../src/runner.mjs';
import { callTool } from '../src/tools.mjs';

const turn = () => new Promise(resolve => setImmediate(resolve));
test('a running instance is a wait: repeated launch calls are delayed, independently per instance', async t => {
  const guard = runner.launchBackoff ?? (send => send);
  const dir = fs.mkdtempSync(join(tmpdir(),'backoff797-'));
  t.after(() => fs.rmSync(dir, {recursive:true,force:true}));
  const calls=[], delays=[]; let now=0;
  const launch = guard(async ({instance}) => {
    calls.push(instance);
    if (instance === 'pm') throw Object.assign(new Error('instance-running'), {code:'instance-running'});
    return {run:'other-run'};
  }, {now:()=>now, wait:ms=>new Promise(resolve=>delays.push({ms,resolve}))});
  const path=join(dir,'tools.sock');
  const server=await runner.toolServer({path,tools:[{name:'launch',verb:'launch'}],client:{},local:{launch}});
  t.after(()=>new Promise(resolve=>server.close(resolve)));
  await assert.rejects(callTool(path,'launch',{instance:'pm'}),/instance-running.*already running.*waiting messages.*claims.*must not launch.*relay/i);
  const second=callTool(path,'launch',{instance:'pm'});
  for(let n=0;n<100 && !delays.length;n++) await new Promise(resolve=>setTimeout(resolve,2));
  assert.deepEqual(calls,['pm']);
  assert.equal(delays.length,1); assert.ok(delays[0].ms >= 30000);
  assert.deepEqual(await callTool(path,'launch',{instance:'coder'}),{run:'other-run'});
  now += delays[0].ms; delays[0].resolve();
  await assert.rejects(second,/instance-running.*already running.*waiting messages.*claims.*must not launch.*relay/i);
  assert.deepEqual(calls,['pm','coder','pm']);
});

test('a success clears the instance-running delay', async () => {
  const guard = runner.launchBackoff ?? (send => send);
  let now=0, calls=0, refusal=true; const waits=[];
  const launch=guard(async () => {calls++; if(refusal) throw Object.assign(new Error('instance-running'),{code:'instance-running'}); return {run:'r1'};},
    {now:()=>now,wait:async ms=>{waits.push(ms);now+=ms;}});
  await assert.rejects(launch({instance:'coder'}),{code:'instance-running'});
  refusal=false;
  assert.deepEqual(await launch({instance:'coder'}),{run:'r1'});
  assert.deepEqual(waits,[30000]);
  assert.deepEqual(await launch({instance:'coder'}),{run:'r1'});
  assert.deepEqual(waits,[30000]); assert.equal(calls,3);
});

test('no-route fails fast and starts no cooldown after the route is set', async () => {
  let calls=0, routed=false; const waits=[];
  const launch=runner.launchBackoff(async () => {
    calls++;
    if (!routed) throw Object.assign(new Error('no-route'), {code:'no-route'});
    return {run:'r1'};
  }, {now:()=>0, wait:async ms=>waits.push(ms)});
  await assert.rejects(launch({instance:'coder'}), {code:'no-route'});
  routed=true;
  assert.deepEqual(await launch({instance:'coder'}), {run:'r1'});
  assert.deepEqual(waits, []);
  assert.equal(calls, 2);
});

test('disconnecting a delayed launch cancels it before it can reach the host', async () => {
  const guard = runner.launchBackoff ?? (send => send);
  let calls=0; const controller=new AbortController();
  const launch=guard(async () => {calls++; throw Object.assign(new Error('instance-running'),{code:'instance-running'});},
    {now:()=>0,wait:(ms,signal)=>new Promise((resolve,reject)=>signal.addEventListener('abort',()=>reject(Object.assign(new Error('cancelled'),{code:'cancelled'})),{once:true}))});
  await assert.rejects(launch({instance:'pm'}),{code:'instance-running'});
  const waiting=launch({instance:'pm'},{signal:controller.signal}).catch(e=>e);
  await turn(); assert.equal(calls,1,'no second host call before the waiting period');
  controller.abort(); await waiting;
  assert.equal(calls,1,'a disconnected caller cannot trigger a later launch');
});

test('simultaneous calls for one instance cannot bypass a refusal', async () => {
  const guard = runner.launchBackoff ?? (send => send);
  let calls=0, finish; const waits=[];
  const launch=guard(async () => {
    calls++;
    if (calls === 1) await new Promise(resolve => { finish=resolve; });
    throw Object.assign(new Error('instance-running'),{code:'instance-running'});
  }, {now:()=>0,wait:ms=>new Promise(resolve=>waits.push({ms,resolve}))});
  const first=launch({instance:'pm'}).catch(e=>e);
  await turn();
  const second=launch({instance:'pm'}).catch(e=>e);
  await turn(); assert.equal(calls,1);
  finish(); await first; await turn();
  assert.equal(calls,1); assert.equal(waits.length,1);
  waits[0].resolve(); await second; assert.equal(calls,2);
});

test('a disconnected tool socket cancels a launch waiting for backoff', async t => {
  const guard = runner.launchBackoff ?? (send => send);
  const dir=fs.mkdtempSync(join(tmpdir(),'backoff797-socket-'));
  t.after(()=>fs.rmSync(dir,{recursive:true,force:true}));
  let calls=0, waiting;
  const launch=guard(async ()=>{calls++;throw Object.assign(new Error('instance-running'),{code:'instance-running'});},
    {now:()=>0,wait:(ms,signal)=>new Promise((resolve,reject)=>{waiting={resolve,signal};signal.addEventListener('abort',()=>reject(new Error('cancelled')),{once:true});})});
  const path=join(dir,'tools.sock');
  const server=await runner.toolServer({path,tools:[{name:'launch',verb:'launch'}],client:{},local:{launch}});
  await assert.rejects(callTool(path,'launch',{instance:'pm'}));
  const socket=connect(path);
  t.after(()=>{ socket.destroy(); return new Promise(resolve=>server.close(resolve)); });
  socket.on('error',()=>{});
  socket.write(JSON.stringify({tool:'launch',args:{instance:'pm'}})+'\n');
  for(let n=0;n<100 && !waiting;n++) await new Promise(resolve=>setTimeout(resolve,2));
  assert.ok(waiting); socket.destroy();
  for(let n=0;n<100 && !waiting.signal.aborted;n++) await new Promise(resolve=>setTimeout(resolve,2));
  assert.equal(waiting.signal.aborted,true);
  waiting.resolve(); await turn(); assert.equal(calls,1);
});