package redisprovider

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

	controllerProvider "proxy-pool/internal/controller/provider"
)

type keyBuilder struct {
	namespace string
}

type upstreamKeys struct {
	generation string
	epoch      string
	leader     string
	next       string
	inflight   string
}

func (builder keyBuilder) forUpstream(upstreamID string) (upstreamKeys, error) {
	if strings.TrimSpace(upstreamID) != upstreamID || upstreamID == "" {
		return upstreamKeys{}, controllerProvider.ErrInvalidCoordination
	}
	digest := digestParts(upstreamID)
	prefix := "pp:" + builder.namespace + ":{provider:" + digest + "}"
	return upstreamKeys{
		generation: prefix + ":generation",
		epoch:      prefix + ":epoch",
		leader:     prefix + ":leader",
		next:       prefix + ":next-request",
		inflight:   prefix + ":inflight",
	}, nil
}

func (keys upstreamKeys) all() []string {
	return []string{keys.generation, keys.epoch, keys.leader, keys.next, keys.inflight}
}

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))
}