// The entry point's contract with core (MODULE_API.md §2.2).
//
// Slice 0 registers nothing, so there is very little behaviour to assert — and
// the rules that DO apply are the ones that would otherwise be discovered on an
// operator's install: registering synchronously, never awaiting, never touching
// a database, never mutating what it was handed. Those hold for every slice
// after this one too, which is why they are tested against the entry point
// rather than against whatever it happens to register today.

const test = require('node:test')
const assert = require('node:assert')

const register = require('../index')
const { fakeCtx, fakeApi } = require('./_fakes')

test('exports a single register function', () => {
  assert.strictEqual(typeof register, 'function')
})

test('registers synchronously and returns nothing to await', () => {
  const result = register(fakeCtx(), fakeApi())
  // Not `assert.strictEqual(result, undefined)` alone: a module that returned a
  // promise would be a module whose registration core silently never waits for.
  assert.ok(!result || typeof result.then !== 'function', 'register() must not return a thenable')
})

test('touches no database at registration time', () => {
  const ctx = fakeCtx()
  register(ctx, fakeApi())
  assert.deepStrictEqual(ctx.db.query.calls, [], 'register() queried the database')
})

test('registers nothing in slice 0', () => {
  const api = fakeApi()
  register(fakeCtx(), api)
  assert.strictEqual(api.record.routes, null)
  assert.strictEqual(api.record.streams, null)
  assert.deepStrictEqual(api.record.extensions, [])
  assert.deepStrictEqual(api.record.legs, [])
  assert.deepStrictEqual(api.record.hooks, {})
})

test('takes a frozen ctx and does not try to write to it', () => {
  const ctx = fakeCtx()
  assert.ok(Object.isFrozen(ctx))
  // Core freezes one level deep; a module that assigned to ctx would throw here
  // in strict mode and fail silently outside it. Either way it must not.
  assert.doesNotThrow(() => register(ctx, fakeApi()))
})

test('logs through ctx.log, never through console', () => {
  const ctx = fakeCtx()
  register(ctx, fakeApi())
  assert.strictEqual(ctx.logs.length, 1, 'expected exactly one logger to be taken')
  const { log } = ctx.logs[0]
  assert.strictEqual(log.info.calls.length, 1)
  assert.strictEqual(log.info.calls[0][0], 'registered')
})

test('carries no hidden state between calls', () => {
  // Core calls register() exactly once, and the `once()` guard that enforces
  // that lives in core's `api` — not here. What this asserts is the module's
  // own half of it: registering into a second `api` produces the same result as
  // the first, so nothing is memoised at file scope where a re-register would
  // silently do less than it appears to.
  const first = fakeApi()
  const second = fakeApi()
  register(fakeCtx(), first)
  register(fakeCtx(), second)
  assert.deepStrictEqual(second.record, first.record)
})