require 'spec_helper'

# Couchbase-backed replacements for common Redis uses: atomic counters, a Rails
# cache store, and a distributed lock — all on the same cluster as the models.
RSpec.describe 'Redis replacements' do
  describe SimplyBased::Counter do
    subject(:counter) { described_class.new }

    it 'atomically increments with Redis INCR semantics (first INCR of a missing key returns the delta)' do
      expect(counter.increment('c:hits')).to eq(1)
      expect(counter.increment('c:hits')).to eq(2)
      expect(counter.increment('c:hits', 5)).to eq(7)
      expect(counter.get('c:hits')).to eq(7)
    end

    it 'seeds at an explicit initial value when given' do
      expect(counter.increment('c:seeded', 1, initial: 100)).to eq(100)
      expect(counter.increment('c:seeded')).to eq(101)
    end

    it 'decrements and resets' do
      counter.increment('c:n', 0, initial: 10)
      expect(counter.decrement('c:n', 3)).to eq(7)
      expect(counter.reset('c:n', 0)).to eq(0)
      expect(counter.get('c:n')).to eq(0)
    end

    it 'clamps decrement at zero (unsigned Couchbase counters; Redis would go negative)' do
      counter.reset('c:clamp', 1)
      expect(counter.decrement('c:clamp', 5)).to eq(0)
    end
  end

  describe SimplyBased::Cache do
    subject(:cache) { described_class.new(namespace: 'test') }

    it 'works as an ActiveSupport::Cache::Store (read/write/fetch/delete)' do
      cache.write('k', { 'a' => 1 })
      expect(cache.read('k')).to eq({ 'a' => 1 })
      expect(cache.fetch('k2') { [1, 2, 3] }).to eq([1, 2, 3])
      expect(cache.read('k2')).to eq([1, 2, 3])
      cache.delete('k')
      expect(cache.read('k')).to be_nil
    end
  end

  describe SimplyBased::Lock do
    subject(:lock) { described_class.new }

    it 'grants the lock to one holder and blocks a second acquire' do
      handle = lock.acquire('job:1', ttl: 30)
      expect(handle).not_to be_nil
      expect(lock.acquire('job:1', ttl: 30)).to be_nil # already held
      lock.release('job:1', handle)
      expect(lock.acquire('job:1', ttl: 30)).not_to be_nil # released → free
    end

    it 'refuses to release without the CAS handle' do
      lock.acquire('job:guard', ttl: 30)
      expect { lock.release('job:guard', nil) }.to raise_error(ArgumentError)
      expect(lock.acquire('job:guard', ttl: 30)).to be_nil # still held
      lock.force_release!('job:guard')
      expect(lock.acquire('job:guard', ttl: 30)).not_to be_nil
    end

    it 'rejects a missing/zero ttl (a crashed holder must never leave an immortal lock)' do
      expect { lock.acquire('job:immortal', ttl: nil) }.to raise_error(ArgumentError)
      expect { lock.acquire('job:immortal', ttl: 0) }.to raise_error(ArgumentError)
    end

    it 'runs a critical section with with_lock' do
      ran = false
      lock.with_lock('job:2') { ran = true }
      expect(ran).to be(true)
      # lock auto-released after the block → re-acquirable
      expect(lock.acquire('job:2')).not_to be_nil
    end
  end
end