package policer

import (
	"context"
	"time"

	"git.frostfs.info/TrueCloudLab/frostfs-node/pkg/core/container"
	"git.frostfs.info/TrueCloudLab/frostfs-node/pkg/core/netmap"
	objectcore "git.frostfs.info/TrueCloudLab/frostfs-node/pkg/core/object"
	"git.frostfs.info/TrueCloudLab/frostfs-node/pkg/services/object_manager/placement"
	"git.frostfs.info/TrueCloudLab/frostfs-node/pkg/services/replicator"
	"git.frostfs.info/TrueCloudLab/frostfs-node/pkg/util/logger"
	netmapSDK "git.frostfs.info/TrueCloudLab/frostfs-sdk-go/netmap"
	objectSDK "git.frostfs.info/TrueCloudLab/frostfs-sdk-go/object"
	oid "git.frostfs.info/TrueCloudLab/frostfs-sdk-go/object/id"
	"github.com/panjf2000/ants/v2"
	"go.uber.org/zap"
)

// KeySpaceIterator is the interface that allows iterating over the key space
// of local storage.
// Note that the underlying implementation might be circular: i.e. it can restart
// when the end of the key space is reached.
type KeySpaceIterator interface {
	Next(context.Context, uint32) ([]objectcore.AddressWithType, error)
	Rewind()
}

// RedundantCopyCallback is a callback to pass
// the redundant local copy of the object.
type RedundantCopyCallback func(context.Context, oid.Address)

// BuryFunc is the function to bury (i.e. inhume) an object.
type BuryFunc func(context.Context, oid.Address) error

// Replicator is the interface to a consumer of replication tasks.
type Replicator interface {
	HandleTask(ctx context.Context, task replicator.Task, res replicator.TaskResult)
}

// RemoteObjectHeaderFunc is the function to obtain HEAD info from a specific remote node.
type RemoteObjectHeaderFunc func(context.Context, netmapSDK.NodeInfo, oid.Address) (*objectSDK.Object, error)

type cfg struct {
	headTimeout time.Duration

	log *logger.Logger

	keySpaceIterator KeySpaceIterator

	buryFn BuryFunc

	cnrSrc container.Source

	placementBuilder placement.Builder

	remoteHeader RemoteObjectHeaderFunc

	netmapKeys netmap.AnnouncedKeys

	replicator Replicator

	cbRedundantCopy RedundantCopyCallback

	taskPool *ants.Pool

	batchSize, cacheSize uint32

	rebalanceFreq, evictDuration, sleepDuration time.Duration

	metrics MetricsRegister
}

func defaultCfg() *cfg {
	return &cfg{
		log:           &logger.Logger{Logger: zap.L()},
		batchSize:     10,
		cacheSize:     1024, // 1024 * address size = 1024 * 64 = 64 MiB
		rebalanceFreq: 1 * time.Second,
		sleepDuration: 1 * time.Second,
		evictDuration: 30 * time.Second,
		metrics:       noopMetrics{},
	}
}

// Option is an option for Policer constructor.
type Option func(*cfg)

// WithHeadTimeout returns option to set Head timeout of Policer.
func WithHeadTimeout(v time.Duration) Option {
	return func(c *cfg) {
		c.headTimeout = v
	}
}

// WithLogger returns option to set Logger of Policer.
func WithLogger(v *logger.Logger) Option {
	return func(c *cfg) {
		c.log = v
	}
}

func WithKeySpaceIterator(it KeySpaceIterator) Option {
	return func(c *cfg) {
		c.keySpaceIterator = it
	}
}

func WithBuryFunc(f BuryFunc) Option {
	return func(c *cfg) {
		c.buryFn = f
	}
}

// WithContainerSource returns option to set container source of Policer.
func WithContainerSource(v container.Source) Option {
	return func(c *cfg) {
		c.cnrSrc = v
	}
}

// WithPlacementBuilder returns option to set object placement builder of Policer.
func WithPlacementBuilder(v placement.Builder) Option {
	return func(c *cfg) {
		c.placementBuilder = v
	}
}

// WithRemoteObjectHeader returns option to set object header receiver of Policer.
func WithRemoteObjectHeaderFunc(v RemoteObjectHeaderFunc) Option {
	return func(c *cfg) {
		c.remoteHeader = v
	}
}

// WithNetmapKeys returns option to set tool to work with announced public keys.
func WithNetmapKeys(v netmap.AnnouncedKeys) Option {
	return func(c *cfg) {
		c.netmapKeys = v
	}
}

// WithReplicator returns option to set object replicator of Policer.
func WithReplicator(v Replicator) Option {
	return func(c *cfg) {
		c.replicator = v
	}
}

// WithRedundantCopyCallback returns option to set
// callback to pass redundant local object copies
// detected by Policer.
func WithRedundantCopyCallback(cb RedundantCopyCallback) Option {
	return func(c *cfg) {
		c.cbRedundantCopy = cb
	}
}

// WithPool returns option to set pool for
// policy and replication operations.
func WithPool(p *ants.Pool) Option {
	return func(c *cfg) {
		c.taskPool = p
	}
}

// WithMetrics returns option to set metrics.
func WithMetrics(m MetricsRegister) Option {
	return func(c *cfg) {
		c.metrics = m
	}
}