package buscompose

import (
	"time"

	"github.com/nats-io/nats.go/jetstream"
)

// The streams a manifest declares, as the server is asked to create them (novox/hq ADR 0547 §5, issue 1790): the
// grants part creates each one the bus does not hold yet, with what the controller asserts at its start, so the two
// make the same stream. Pure. Only a create is ever asked with these: a stream the bus holds is never updated by the
// grants part (CreateStreamGrants grants no update).

// BucketStreamConfig is a module's bucket as the stream the controller's CreateOrUpdateKeyValue makes of its options
// (mesh-controller internal/broker BucketConfig, with no marker age held): the client library's key-value shape
// (rollup, no delete, direct reads, discard new, a duplicate window of two minutes or the age when shorter) with the
// mesh's caps, file storage and one replica.
func BucketStreamConfig(b Bucket) jetstream.StreamConfig {
	history := b.History
	if history < 1 {
		history = 1
	}
	age := time.Duration(b.TTLSeconds) * time.Second
	dupes := 2 * time.Minute
	if age > 0 && age < dupes {
		dupes = age
	}
	cfg := jetstream.StreamConfig{
		Name:              "KV_" + b.Bucket(),
		Description:       b.Why(),
		Subjects:          []string{"$KV." + b.Bucket() + ".>"},
		MaxMsgsPerSubject: int64(history),
		MaxBytes:          StateMaxBytes,
		MaxAge:            age,
		MaxMsgSize:        StateMaxValueBytes,
		Storage:           jetstream.FileStorage,
		Replicas:          1,
		AllowRollup:       true,
		DenyDelete:        true,
		Duplicates:        dupes,
		MaxMsgs:           -1,
		MaxConsumers:      -1,
		AllowDirect:       true,
		Discard:           jetstream.DiscardNew,
	}
	if b.KeyTTL {
		cfg.AllowMsgTTL, cfg.SubjectDeleteMarkerTTL = true, KeyTTLMarkerTTL
	}
	return cfg
}

// ModuleStreamConfig is a module's own stream as the controller asserts it (mesh-controller internal/broker
// StreamConfigFor of ModuleStream.Stream).
func ModuleStreamConfig(m ModuleStream) jetstream.StreamConfig {
	s := m.Stream()
	cfg := jetstream.StreamConfig{
		Name:              s.Name,
		Subjects:          s.Subjects,
		Retention:         jetstream.LimitsPolicy,
		MaxAge:            time.Duration(s.MaxAge) * time.Second,
		MaxMsgsPerSubject: int64(s.MaxMsgsPerSubject),
		Description:       s.Why,
		AllowDirect:       s.Direct,
		AllowMsgTTL:       s.AllowMsgTTL,
	}
	if s.Retention == RetentionWorkQueue {
		cfg.Retention = jetstream.WorkQueuePolicy
	}
	if s.Restricted || s.WorkQueue {
		cfg.Metadata = map[string]string{}
		if s.Restricted {
			cfg.Metadata[RestrictedMetadata] = "true"
		}
		if s.WorkQueue {
			cfg.Metadata[WorkQueueMetadata] = "true"
		}
	}
	if s.MaxBytes > 0 {
		cfg.MaxBytes = s.MaxBytes
	}
	if s.DiscardNew {
		cfg.Discard = jetstream.DiscardNew
	}
	if s.DuplicatesSeconds > 0 {
		cfg.Duplicates = time.Duration(s.DuplicatesSeconds) * time.Second
	}
	return cfg
}