// Copyright (c) 2017 Uber Technologies, Inc.
//
// 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 collection

import (
	"errors"
	"log"
	"os"
	"testing"

	"github.com/stretchr/testify/suite"
)

type (
	pagingIteratorSuite struct {
		suite.Suite
	}
)

func TestPagingIteratorSuite(t *testing.T) {
	s := new(pagingIteratorSuite)
	suite.Run(t, s)
}

func (s *pagingIteratorSuite) SetupSuite() {
	if testing.Verbose() {
		log.SetOutput(os.Stdout)
	}

}

func (s *pagingIteratorSuite) TearDownSuite() {

}

func (s *pagingIteratorSuite) SetupTest() {

}

func (s *pagingIteratorSuite) TearDownTest() {

}

func (s *pagingIteratorSuite) TestIteration_NoErr() {
	phase := 0
	outputs := [][]interface{}{
		[]interface{}{1, 2, 3, 4, 5},
		[]interface{}{},
		[]interface{}{6},
		[]interface{}{},
	}
	tokens := [][]byte{
		[]byte("some random token 1"),
		[]byte("some random token 2"),
		[]byte("some random token 3"),
		[]byte(nil),
	}
	pagingFn := func(token []byte) ([]interface{}, []byte, error) {
		switch phase {
		case 0:
			s.Equal(0, len(token))
			defer func() { phase++ }()
			return outputs[phase], tokens[phase], nil
		case 1:
			s.Equal(tokens[0], token)
			defer func() { phase++ }()
			return outputs[phase], tokens[phase], nil
		case 2:
			s.Equal(tokens[1], token)
			defer func() { phase++ }()
			return outputs[phase], tokens[phase], nil
		case 3:
			s.Equal(tokens[2], token)
			defer func() { phase++ }()
			return outputs[phase], tokens[phase], nil
		default:
			panic("should not reach here during test")
		}
	}

	result := []int{}
	ite := NewPagingIterator(pagingFn)
	for ite.HasNext() {
		item, err := ite.Next()
		s.Nil(err)
		num, ok := item.(int)
		s.True(ok)
		result = append(result, num)
	}
	s.Equal([]int{1, 2, 3, 4, 5, 6}, result)
}

func (s *pagingIteratorSuite) TestIteration_Err_Beginging() {
	phase := 0
	ite := NewPagingIterator(func(token []byte) ([]interface{}, []byte, error) {
		switch phase {
		case 0:
			defer func() { phase++ }()
			return nil, nil, errors.New("some random error")
		default:
			panic("should not reach here during test")
		}
	})

	s.True(ite.HasNext())
	item, err := ite.Next()
	s.Nil(item)
	s.NotNil(err)
	s.False(ite.HasNext())
}

func (s *pagingIteratorSuite) TestIteration_Err_NotBegining() {

	phase := 0
	outputs := [][]interface{}{
		[]interface{}{1, 2, 3, 4, 5},
	}
	tokens := [][]byte{
		[]byte("some random token 1"),
	}
	pagingFn := func(token []byte) ([]interface{}, []byte, error) {
		switch phase {
		case 0:
			s.Equal(0, len(token))
			defer func() { phase++ }()
			return outputs[phase], tokens[phase], nil
		case 1:
			s.Equal(tokens[0], token)
			defer func() { phase++ }()
			return nil, nil, errors.New("some random error")
		default:
			panic("should not reach here during test")
		}
	}

	result := []int{}
	ite := NewPagingIterator(pagingFn)
	for ite.HasNext() {
		item, err := ite.Next()
		if err != nil {
			break
		}
		num, ok := item.(int)
		s.True(ok)
		result = append(result, num)
	}
	s.Equal([]int{1, 2, 3, 4, 5}, result)
}
