package kv

import (
	"fmt"

	endure "github.com/spiral/endure/pkg/container"
	"github.com/spiral/errors"
	"github.com/spiral/roadrunner/v2/common/kv"
	"github.com/spiral/roadrunner/v2/plugins/config"
	"github.com/spiral/roadrunner/v2/plugins/logger"
)

// PluginName linked to the memory, boltdb, memcached, redis plugins. DO NOT change w/o sync.
const PluginName string = "kv"

const (
	// driver is the mandatory field which should present in every storage
	driver string = "driver"
)

// Plugin for the unified storage
type Plugin struct {
	log logger.Logger
	// constructors contains general storage constructors, such as boltdb, memory, memcached, redis.
	constructors map[string]kv.Constructor
	// storages contains user-defined storages, such as boltdb-north, memcached-us and so on.
	storages map[string]kv.Storage
	// KV configuration
	cfg       Config
	cfgPlugin config.Configurer
}

func (p *Plugin) Init(cfg config.Configurer, log logger.Logger) error {
	const op = errors.Op("kv_plugin_init")
	if !cfg.Has(PluginName) {
		return errors.E(errors.Disabled)
	}

	err := cfg.UnmarshalKey(PluginName, &p.cfg.Data)
	if err != nil {
		return errors.E(op, err)
	}
	p.constructors = make(map[string]kv.Constructor, 5)
	p.storages = make(map[string]kv.Storage, 5)
	p.log = log
	p.cfgPlugin = cfg
	return nil
}

func (p *Plugin) Serve() chan error {
	errCh := make(chan error, 1)
	const op = errors.Op("kv_plugin_serve")
	// key - storage name in the config
	// value - storage
	// For this config we should have 3 constructors: memory, boltdb and memcached but 4 KVs: default, boltdb-south, boltdb-north and memcached
	// when user requests for example boltdb-south, we should provide that particular preconfigured storage

	for k, v := range p.cfg.Data {
		// for example if the key not properly formatted (yaml)
		if v == nil {
			continue
		}

		// check type of the v
		// should be a map[string]interface{}
		switch t := v.(type) {
		// correct type
		case map[string]interface{}:
			if _, ok := t[driver]; !ok {
				errCh <- errors.E(op, errors.Errorf("could not find mandatory driver field in the %s storage", k))
				return errCh
			}
		default:
			p.log.Warn("wrong type detected in the configuration, please, check yaml indentation")
			continue
		}

		// config key for the particular sub-driver kv.memcached
		configKey := fmt.Sprintf("%s.%s", PluginName, k)
		// at this point we know, that driver field present in the configuration
		drName := v.(map[string]interface{})[driver]

		// driver name should be a string
		if drStr, ok := drName.(string); ok {
			if _, ok := p.constructors[drStr]; !ok {
				p.log.Warn("no constructors registered", "requested constructor", drStr, "registered", p.constructors)
				continue
			}

			storage, err := p.constructors[drStr].KVConstruct(configKey)
			if err != nil {
				errCh <- errors.E(op, err)
				return errCh
			}

			// save the storage
			p.storages[k] = storage
		}

		continue
	}

	return errCh
}

func (p *Plugin) Stop() error {
	return nil
}

// Collects will get all plugins which implement Storage interface
func (p *Plugin) Collects() []interface{} {
	return []interface{}{
		p.GetAllStorageDrivers,
	}
}

func (p *Plugin) GetAllStorageDrivers(name endure.Named, constructor kv.Constructor) {
	// save the storage constructor
	p.constructors[name.Name()] = constructor
}

// RPC returns associated rpc service.
func (p *Plugin) RPC() interface{} {
	return &rpc{srv: p, log: p.log, storages: p.storages}
}

func (p *Plugin) Name() string {
	return PluginName
}

// Available interface implementation
func (p *Plugin) Available() {}