// Copyright (C) 2022 The OKit Authors
//
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in all
// copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
// EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
// IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
// DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
// OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE
// OR OTHER DEALINGS IN THE SOFTWARE.

package okit

import (
	"context"
)

var (
	global chan Client
)

func init() {
	global = make(chan Client, 1)
	global <- NewClient()
}

// Replace updates the default Client to be the provided one.
func Replace(c Client) {
	<-global
	global <- c
}

// C returns a copy of the current default Client.
func C() Client {
	c := <-global
	global <- c

	return c
}

// ContextKey is a holder structure that allows data to be attached to contexts.
type ContextKey string

// SpanKey identifies a span on a given context.
var SpanKey = ContextKey("okit.span")

// With returns a client containing additional tags.
func With(tags ...Tag) Client {
	return C().With(tags...)
}

// Emit emits an event with the provided tags.
func Emit(event string, tags ...Tag) {
	C().WithCallerSkip(3).Emit(event, tags...)
}

// Observe reports a metric value with the provided tags.
func Observe(metric string, value float64, tags ...Tag) {
	C().WithCallerSkip(3).Observe(metric, value, tags...)
}

// Trace traces a function call. It implements distributed tracing and bookend events.
func Trace(ctxp *context.Context, tags ...Tag) ActiveTrace {
	return C().WithCallerSkip(3).Trace(ctxp, tags...)
}

// Debug writes a message at a debug level.
func Debug(msg string, tags ...Tag) {
	C().WithCallerSkip(3).Debug(msg, tags...)
}

// Info writes a message at a informational level.
func Info(msg string, tags ...Tag) {
	C().WithCallerSkip(3).Info(msg, tags...)
}

// Warn writes a message at a warning level.
func Warn(msg string, tags ...Tag) {
	C().WithCallerSkip(3).Warn(msg, tags...)
}

// Error writes a message at a error level.
func Error(msg string, tags ...Tag) {
	C().WithCallerSkip(3).Error(msg, tags...)
}