// Package store defines MCP Nexus's persistence interfaces (ARCHITECTURE §8)
// and an in-memory implementation used for Phase 1 and tests. A SQLite-backed
// implementation lands in a later brick behind the same interfaces.
package store

import (
	"context"
	"sort"
	"sync"

	"gitea.thetempleofdoom.com/drjones/mcp-gateway-nexus/internal/domain"
)

// InstanceStore persists MCP instances (the observed/desired state the
// reconciler manages).
type InstanceStore interface {
	PutInstance(ctx context.Context, inst domain.MCPInstance) error
	GetInstance(ctx context.Context, id string) (domain.MCPInstance, bool, error)
	ListInstances(ctx context.Context) ([]domain.MCPInstance, error)
	DeleteInstance(ctx context.Context, id string) error
}

// Store aggregates all persistence surfaces. It will grow as later modules
// (registry, identity, secrets, audit) come online.
type Store interface {
	InstanceStore
}

// Memory is a thread-safe in-memory Store.
type Memory struct {
	mu        sync.RWMutex
	instances map[string]domain.MCPInstance
}

// NewMemory creates an empty in-memory store.
func NewMemory() *Memory {
	return &Memory{instances: make(map[string]domain.MCPInstance)}
}

func (m *Memory) PutInstance(_ context.Context, inst domain.MCPInstance) error {
	m.mu.Lock()
	defer m.mu.Unlock()
	m.instances[inst.ID] = inst
	return nil
}

func (m *Memory) GetInstance(_ context.Context, id string) (domain.MCPInstance, bool, error) {
	m.mu.RLock()
	defer m.mu.RUnlock()
	inst, ok := m.instances[id]
	return inst, ok, nil
}

func (m *Memory) ListInstances(_ context.Context) ([]domain.MCPInstance, error) {
	m.mu.RLock()
	defer m.mu.RUnlock()
	out := make([]domain.MCPInstance, 0, len(m.instances))
	for _, inst := range m.instances {
		out = append(out, inst)
	}
	sort.Slice(out, func(i, j int) bool { return out[i].ID < out[j].ID })
	return out, nil
}

func (m *Memory) DeleteInstance(_ context.Context, id string) error {
	m.mu.Lock()
	defer m.mu.Unlock()
	delete(m.instances, id)
	return nil
}

var _ Store = (*Memory)(nil)