// ------------------------------------------------------------------------
//   Project atila
//   Active Thing (activething.com) git.activething.com/go
//
//   File name  pool.go
//   Created by DEV
//   Modified   17/01/2024
//
//   Copyright 2024 activething.com
// ------------------------------------------------------------------------
// 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 pools

import (
	"opts"
	"sync"
	"sync/atomic"
)

type (

	GPool[T any] struct {
		PoolStatsInfo

		inner sync.Pool

		cap int32
		len int32

		createFn func() *T
	}
)

func NewGPool[T any](ops ...opts.GOptionFnc[GPool[T]]) *GPool[T] {
	return opts.GApply(&GPool[T]{}, ops...) }


func (p *GPool[T]) Len() int32 {
	return atomic.LoadInt32(&p.len) }


func (p *GPool[T]) Cap() int32 {
	return atomic.LoadInt32(&p.cap) }


func (p *GPool[T]) Get() *T {
	o := p.inner.Get()
	if o != nil {
		p.AddAcquired()
		if p.Len() > 0 {
			atomic.AddInt32(&p.len, -1)
		}
		return o.(*T)
	}
	if o = p.createFn(); o != nil {
		p.AddCreated()
	}
	return o.(*T)
}


func (p *GPool[T]) Put(obj *T) {
	if obj == nil {
		return
	}
	c := p.Cap()
	p.AddReleased()
	if c == -1 || c >= p.Len() {
		atomic.AddInt32(&p.len, 1)
		p.inner.Put(obj)
	}
}


func (p *GPool[T]) Empty() {
	for p.Len() > 0 {
		_ = p.Get()
	}
}




func WithNew[T any](nfn func() *T) opts.GOptionFnc[GPool[T]] {
	return func(p *GPool[T]) {
		p.createFn = nfn
	}
}


func WithCap[T any](cap int32) opts.GOptionFnc[GPool[T]] {
	return func(p *GPool[T]) {
		atomic.StoreInt32(&p.cap, cap)
	}
}


func WithLen[T any](len int32) opts.GOptionFnc[GPool[T]] {
	return func(p *GPool[T]) {
		if p.createFn == nil {
			return
		}
		c := p.Cap()
		if c != -1 && len > c {
			len = c
		}
		for i := int32(0); i < len; i++ {
			p.Put(p.createFn())
		}
	}
}


func WithSet[T any](els ...*T) opts.GOptionFnc[GPool[T]] {
	return func(p *GPool[T]) {
		for _, e := range els {
			if e != nil {
				p.Put(e)
			}
		}
	}
}