// Copyright 2020 Douyu
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

package conf

import (
	"io"

	"github.com/davecgh/go-spew/spew"
)

// DataSource ...
type DataSource interface {
	ReadConfig() ([]byte, error)
	IsConfigChanged() <-chan struct{}
	io.Closer
}

// Unmarshaller ...
type Unmarshaller = func([]byte, interface{}) error

var defaultConfiguration = New()

// OnChange 注册change回调函数
func OnChange(fn func(*Configuration)) {
	defaultConfiguration.OnChange(fn)
}

// LoadFromDataSource load configuration from data source
// if data source supports dynamic config, a monitor goroutinue
// would be
func LoadFromDataSource(ds DataSource, unmarshaller Unmarshaller) error {
	return defaultConfiguration.LoadFromDataSource(ds, unmarshaller)
}

// Load loads configuration from provided provider with default defaultConfiguration.
func LoadFromReader(r io.Reader, unmarshaller Unmarshaller) error {
	return defaultConfiguration.LoadFromReader(r, unmarshaller)
}

// Apply ...
func Apply(conf map[string]interface{}) error {
	return defaultConfiguration.apply(conf)
}

// Reset resets all to default settings.
func Reset() {
	defaultConfiguration = New()
}

// Traverse ...
func Traverse(sep string) map[string]interface{} {
	return defaultConfiguration.traverse(sep)
}

// Debug ...
func Debug(sep string) {
	spew.Dump("Debug", Traverse(sep))
}

// Get returns an interface. For a specific value use one of the Get____ methods.
func Get(key string) interface{} {
	return defaultConfiguration.Get(key)
}

// Set set config value for key
func Set(key string, val interface{}) {
	defaultConfiguration.Set(key, val)
}