package redis

import (
	"context"
	"time"

	"forge.cadoles.com/cadoles/bouncer/internal/store"
	"github.com/pkg/errors"
	"github.com/redis/go-redis/v9"
)

const (
	keyPrefixLayer = "layer"
)

type LayerRepository struct {
	client redis.UniversalClient
}

// CreateLayer implements store.LayerRepository
func (r *LayerRepository) CreateLayer(ctx context.Context, proxyName store.ProxyName, layerName store.LayerName, layerType store.LayerType, options store.LayerOptions) (*store.Layer, error) {
	now := time.Now().UTC()
	key := layerKey(proxyName, layerName)

	layerItem := &layerItem{
		layerHeaderItem: layerHeaderItem{
			Proxy:   string(proxyName),
			Name:    string(layerName),
			Type:    string(layerType),
			Weight:  0,
			Enabled: false,
		},

		CreatedAt: wrap(now),
		UpdatedAt: wrap(now),
		Options:   wrap(map[string]any{}),
	}

	txf := func(tx *redis.Tx) error {
		exists, err := tx.Exists(ctx, key).Uint64()
		if err != nil {
			return errors.WithStack(err)
		}

		if exists > 0 {
			return errors.WithStack(store.ErrAlreadyExist)
		}

		_, err = tx.TxPipelined(ctx, func(p redis.Pipeliner) error {
			p.HMSet(ctx, key, &layerItem.layerHeaderItem)
			p.HMSet(ctx, key, layerItem)

			return nil
		})

		if err != nil {
			return errors.WithStack(err)
		}

		return nil
	}

	err := r.client.Watch(ctx, txf, key)
	if err != nil {
		return nil, errors.WithStack(err)
	}

	return &store.Layer{
		LayerHeader: store.LayerHeader{
			Name:    layerName,
			Proxy:   proxyName,
			Type:    layerType,
			Weight:  0,
			Enabled: false,
		},

		CreatedAt: now,
		UpdatedAt: now,
		Options:   map[string]any{},
	}, nil
}

// DeleteLayer implements store.LayerRepository
func (r *LayerRepository) DeleteLayer(ctx context.Context, proxyName store.ProxyName, layerName store.LayerName) error {
	key := layerKey(proxyName, layerName)

	if cmd := r.client.Del(ctx, key); cmd.Err() != nil {
		return errors.WithStack(cmd.Err())
	}

	return nil
}

// GetLayer implements store.LayerRepository
func (r *LayerRepository) GetLayer(ctx context.Context, proxyName store.ProxyName, layerName store.LayerName) (*store.Layer, error) {
	key := layerKey(proxyName, layerName)

	layerItem := &layerItem{}

	cmd := r.client.Exists(ctx, key)
	if err := cmd.Err(); err != nil {
		return nil, errors.WithStack(err)
	}

	if count := cmd.Val(); count == 0 {
		return nil, errors.WithStack(store.ErrNotFound)
	}

	if err := r.client.HGetAll(ctx, key).Scan(&layerItem.layerHeaderItem); err != nil {
		return nil, errors.WithStack(err)
	}

	if err := r.client.HGetAll(ctx, key).Scan(layerItem); err != nil {
		return nil, errors.WithStack(err)
	}

	layer, err := layerItem.ToLayer()
	if err != nil {
		return nil, errors.WithStack(err)
	}

	return layer, nil
}

// QueryLayers implements store.LayerRepository
func (r *LayerRepository) QueryLayers(ctx context.Context, proxyName store.ProxyName, funcs ...store.QueryLayerOptionFunc) ([]*store.LayerHeader, error) {
	opts := store.DefaultQueryLayerOptions()
	for _, fn := range funcs {
		fn(opts)
	}

	keyParts := []string{keyPrefixLayer, string(proxyName)}

	if opts.Name != nil {
		keyParts = append(keyParts, string(*opts.Name))
	} else {
		keyParts = append(keyParts, "*")
	}

	key := key(keyParts...)

	iter := r.client.Scan(ctx, uint64(*opts.Offset), key, int64(*opts.Limit)).Iterator()

	headers := make([]*store.LayerHeader, 0)

	for iter.Next(ctx) {
		key := iter.Val()

		layerHeaderItem := &layerHeaderItem{}

		if err := r.client.HGetAll(ctx, key).Scan(layerHeaderItem); err != nil {
			return nil, errors.WithStack(err)
		}

		layerHeader, err := layerHeaderItem.ToLayerHeader()
		if err != nil {
			return nil, errors.WithStack(err)
		}

		headers = append(headers, layerHeader)
	}

	if err := iter.Err(); err != nil {
		return nil, errors.WithStack(err)
	}

	return headers, nil
}

// UpdateLayer implements store.LayerRepository
func (r *LayerRepository) UpdateLayer(ctx context.Context, proxyName store.ProxyName, layerName store.LayerName, options store.LayerOptions) error {
	panic("unimplemented")
}

func NewLayerRepository(client redis.UniversalClient) *LayerRepository {
	return &LayerRepository{
		client: client,
	}
}

var _ store.LayerRepository = &LayerRepository{}

func layerKey(proxyName store.ProxyName, layerName store.LayerName) string {
	return key(keyPrefixLayer, string(proxyName), string(layerName))
}