package openstack

import (
	"context"
	"fmt"
	"sync"
)

// MockClient is an in-memory FloatingIPClient used by unit tests and the
// offline end-to-end harness. Seed it with the pool of floating IPs the
// scenario expects to exist before use.
type MockClient struct {
	mu   sync.Mutex
	fips map[string]*FloatingIP // keyed by ID
	byIP map[string]string      // address -> ID

	// AssociateFailures/DisassociateFailures let tests force a failure for
	// a specific floating-IP ID on its next call, to exercise retry paths.
	AssociateFailures    map[string]error
	DisassociateFailures map[string]error
}

func NewMockClient() *MockClient {
	return &MockClient{
		fips: make(map[string]*FloatingIP),
		byIP: make(map[string]string),
	}
}

// Seed registers a floating IP as if pre-allocated in the service project.
func (m *MockClient) Seed(id, address, projectID string) {
	m.mu.Lock()
	defer m.mu.Unlock()
	m.fips[id] = &FloatingIP{ID: id, Address: address, ProjectID: projectID}
	m.byIP[address] = id
}

// SeedWithPort registers a floating IP as already associated to portID —
// for simulating a FIP that's occupied (e.g. by another VM's port) before a
// test's Tick runs.
func (m *MockClient) SeedWithPort(id, address, projectID, portID string) {
	m.mu.Lock()
	defer m.mu.Unlock()
	m.fips[id] = &FloatingIP{ID: id, Address: address, ProjectID: projectID, PortID: portID}
	m.byIP[address] = id
}

func (m *MockClient) GetFloatingIPByAddress(ctx context.Context, address string) (*FloatingIP, error) {
	m.mu.Lock()
	defer m.mu.Unlock()
	id, ok := m.byIP[address]
	if !ok {
		return nil, ErrNotFound(address)
	}
	f := *m.fips[id]
	return &f, nil
}

func (m *MockClient) AssociateFloatingIP(ctx context.Context, fipID, portID string) error {
	m.mu.Lock()
	defer m.mu.Unlock()
	if err := m.AssociateFailures[fipID]; err != nil {
		delete(m.AssociateFailures, fipID)
		return err
	}
	f, ok := m.fips[fipID]
	if !ok {
		return fmt.Errorf("mock openstack: unknown floating ip %q", fipID)
	}
	f.PortID = portID
	return nil
}

func (m *MockClient) DisassociateFloatingIP(ctx context.Context, fipID string) error {
	m.mu.Lock()
	defer m.mu.Unlock()
	if err := m.DisassociateFailures[fipID]; err != nil {
		delete(m.DisassociateFailures, fipID)
		return err
	}
	f, ok := m.fips[fipID]
	if !ok {
		return fmt.Errorf("mock openstack: unknown floating ip %q", fipID)
	}
	f.PortID = ""
	return nil
}