package redisactivity

import (
	"crypto/sha256"
	"encoding/hex"
	"strconv"
)

const redisKeyPrefix = "pp:{activity}:"

type keyspace struct {
	prefix         string
	records        string
	unique         string
	idkeys         string
	expiry         string
	available      string
	owners         string
	ownerExpiry    string
	epoch          string
	inventory      string
	stateInventory string
}

func newKeyspace(namespace string) keyspace {
	prefix := redisKeyPrefix + namespace
	return keyspace{
		prefix:         prefix,
		records:        prefix + ":records",
		unique:         prefix + ":unique",
		idkeys:         prefix + ":idkeys",
		expiry:         prefix + ":expiry",
		available:      prefix + ":available",
		owners:         prefix + ":owners",
		ownerExpiry:    prefix + ":owner-expiry",
		epoch:          prefix + ":epoch",
		inventory:      prefix + ":inventory",
		stateInventory: prefix + ":state-inventory",
	}
}

func stateInventoryField(upstreamID, state string) string {
	return strconv.Itoa(len(upstreamID)) + ":" + upstreamID + ":" + state
}

func (keys keyspace) idempotency(clientID, idempotencyKey string) string {
	return keys.prefix + ":idem:" + digestParts(clientID, idempotencyKey)
}

func (keys keyspace) operation(operationID string) string {
	return keys.prefix + ":op:" + digestToken(operationID)
}

func (keys keyspace) protocol(value string) string {
	return keys.facet("protocol", value)
}

func (keys keyspace) region(value string) string {
	return keys.facet("region", value)
}

func (keys keyspace) carrier(value string) string {
	return keys.facet("carrier", value)
}

func (keys keyspace) upstream(value string) string {
	return keys.facet("upstream", value)
}

func (keys keyspace) facet(name, value string) string {
	return keys.prefix + ":" + name + ":" + digestToken(value)
}

func digestToken(value string) string {
	return digestParts(value)
}

func digestParts(values ...string) string {
	digest := sha256.New()
	for _, value := range values {
		_, _ = digest.Write([]byte(strconv.Itoa(len(value))))
		_, _ = digest.Write([]byte{':'})
		_, _ = digest.Write([]byte(value))
	}
	return hex.EncodeToString(digest.Sum(nil))
}