package cache

import (
	"fmt"
	"time"

	"github.com/apex/log"
	"github.com/sparetimecoders/goamqp"

	"gitlab.com/unboundsoftware/schemas/domain"
)

const subGraphKey = "%s<->%s"

type Cache struct {
	services   map[string]map[string]struct{}
	subGraphs  map[string]string
	lastUpdate map[string]string
	logger     log.Interface
}

func (c *Cache) Services(ref, lastUpdate string) ([]string, string) {
	var services []string
	if lastUpdate == "" || c.lastUpdate[ref] > lastUpdate {
		for k := range c.services[ref] {
			services = append(services, k)
		}
	}
	return services, c.lastUpdate[ref]
}

func (c *Cache) SubGraphId(ref, service string) string {
	return c.subGraphs[fmt.Sprintf(subGraphKey, ref, service)]
}

func (c *Cache) Update(msg any, _ goamqp.Headers) (any, error) {
	switch m := msg.(type) {
	case *domain.SubGraphUpdated:
		if _, exists := c.services[m.Ref]; !exists {
			c.services[m.Ref] = make(map[string]struct{})
		}
		c.services[m.Ref][m.ID.String()] = struct{}{}
		c.subGraphs[fmt.Sprintf(subGraphKey, m.Ref, m.Service)] = m.ID.String()
		c.lastUpdate[m.Ref] = m.Time.Format(time.RFC3339Nano)
	case *domain.SubGraph:
		if _, exists := c.services[m.Ref]; !exists {
			c.services[m.Ref] = make(map[string]struct{})
		}
		c.services[m.Ref][m.ID.String()] = struct{}{}
		c.subGraphs[fmt.Sprintf(subGraphKey, m.Ref, m.Service)] = m.ID.String()
		c.lastUpdate[m.Ref] = m.ChangedAt.Format(time.RFC3339Nano)
	default:
		c.logger.Warnf("unexpected message received: %+v", msg)
	}
	return nil, nil
}

func New(logger log.Interface) *Cache {
	return &Cache{
		subGraphs:  make(map[string]string),
		services:   make(map[string]map[string]struct{}),
		lastUpdate: make(map[string]string),
		logger:     logger,
	}
}