package cache

import (
	"testing"

	. "github.com/smartystreets/goconvey/convey"
)

func Test_FirstContainsIndex(t *testing.T) {
	cases := []struct {
		title string
		arr   []*Range
		pos   int64
		want  int
	}{
		{
			"空数组",
			[]*Range{},
			100,
			-1,
		},
		{
			"只有一个元素，pos在范围内",
			[]*Range{{100, 100}},
			100,
			0,
		},
		{
			"区间不连续，但在范围内-奇数区间数",
			[]*Range{{100, 100}, {300, 100}, {500, 100}},
			350,
			1,
		},
		{
			"区间不连续，但在范围内-偶数区间数",
			[]*Range{{100, 100}, {300, 100}},
			350,
			1,
		},
		{
			"区间不连续，pos在最左边",
			[]*Range{{100, 100}, {300, 100}, {500, 100}},
			10,
			-1,
		},
		{
			"区间不连续，pos在靠左的第一个空洞中",
			[]*Range{{100, 100}, {300, 100}, {500, 100}},
			200,
			0,
		},
		{
			"区间不连续，pos在靠左的第一个空洞中-偶数区间数",
			[]*Range{{100, 100}, {300, 100}, {500, 100}, {700, 100}},
			200,
			0,
		},
		{
			"区间不连续，pos在最右边",
			[]*Range{{100, 100}, {300, 100}, {500, 100}},
			601,
			2,
		},
	}

	for _, c := range cases {
		Convey(c.title, t, func() {
			got := FirstContainsIndex(c.arr, c.pos)
			So(got, ShouldEqual, c.want)
		})
	}
}

func Test_AddRange(t *testing.T) {
	cases := []struct {
		title string
		arr   []*Range
		r     *Range
		want  []*Range
	}{
		{
			"空数组",
			[]*Range{},
			&Range{100, 100},
			[]*Range{{100, 100}},
		},
		{
			"单个区间，连接在左侧",
			[]*Range{{100, 100}},
			&Range{0, 100},
			[]*Range{{0, 200}},
		},
		{
			"单个区间，连接在右侧",
			[]*Range{{100, 100}},
			&Range{200, 100},
			[]*Range{{100, 200}},
		},
		{
			"单个区间，左边重叠了一部分",
			[]*Range{{100, 100}},
			&Range{50, 100},
			[]*Range{{50, 150}},
		},
		{
			"单个区间，右边重叠了一部分",
			[]*Range{{100, 100}},
			&Range{150, 100},
			[]*Range{{100, 150}},
		},
		{
			"单个区间，被新区间完全覆盖",
			[]*Range{{100, 100}},
			&Range{50, 150},
			[]*Range{{50, 150}},
		},
		{
			"单个区间，在左边但有空洞",
			[]*Range{{100, 100}},
			&Range{0, 50},
			[]*Range{{0, 50}, {100, 100}},
		},
		{
			"单个区间，在右边但有空洞",
			[]*Range{{100, 100}},
			&Range{250, 50},
			[]*Range{{100, 100}, {250, 50}},
		},
		{
			"恰好连接了两个区间",
			[]*Range{{100, 100}, {300, 100}},
			&Range{200, 100},
			[]*Range{{100, 300}},
		},
		{
			"连接了两个区间，但在左边有重叠",
			[]*Range{{100, 100}, {300, 100}},
			&Range{150, 150},
			[]*Range{{100, 300}},
		},
		{
			"连接了两个区间，但在右边有重叠",
			[]*Range{{100, 100}, {300, 100}},
			&Range{150, 200},
			[]*Range{{100, 300}},
		},
		{
			"覆盖了多个区间，但不是完全连接",
			[]*Range{{100, 100}, {300, 100}, {500, 100}, {700, 100}},
			&Range{150, 400},
			[]*Range{{100, 500}, {700, 100}},
		},
		{
			"完全覆盖所有区间",
			[]*Range{{100, 100}, {300, 100}, {500, 100}, {700, 100}},
			&Range{0, 900},
			[]*Range{{0, 900}},
		},
	}

	for _, c := range cases {
		Convey(c.title, t, func() {
			got := AddRange(c.arr, c.r)
			So(got, ShouldResemble, c.want)
		})
	}
}

func Test_MergeRanges(t *testing.T) {
	cases := []struct {
		title string
		arr1  []*Range
		arr2  []*Range
		want  []*Range
	}{
		{
			"两个都是空数组",
			[]*Range{},
			[]*Range{},
			nil,
		},
		{
			"其中一个是空数组",
			[]*Range{{100, 100}},
			[]*Range{},
			[]*Range{{100, 100}},
		},
		{
			"两个都是单个区间，没有重叠",
			[]*Range{{100, 100}},
			[]*Range{{300, 100}},
			[]*Range{{100, 100}, {300, 100}},
		},
		{
			"两个都是单个区间，恰好连接",
			[]*Range{{100, 100}},
			[]*Range{{200, 100}},
			[]*Range{{100, 200}},
		},
		{
			"两个都是单个区间，有重叠",
			[]*Range{{100, 100}},
			[]*Range{{150, 100}},
			[]*Range{{100, 150}},
		},
		{
			"多区间恰好连接",
			[]*Range{{100, 100}, {300, 100}, {500, 100}},
			[]*Range{{200, 100}, {400, 100}},
			[]*Range{{100, 500}},
		},
		{
			"多区间各种情况",
			[]*Range{{100, 100}, {300, 100}, {500, 100}, {700, 100}},
			[]*Range{{150, 100}, {260, 90}, {400, 100}, {550, 250}},
			[]*Range{{100, 150}, {260, 540}},
		},
	}

	for _, c := range cases {
		Convey(c.title, t, func() {
			got := MergeRanges(c.arr1, c.arr2)
			So(got, ShouldResemble, c.want)
		})
	}
}

func Test_TruncateRange(t *testing.T) {
	cases := []struct {
		title string
		arr   []*Range
		pos   int64
		want  []*Range
	}{
		{
			"空数组",
			[]*Range{},
			100,
			[]*Range{},
		},
		{
			"截断的长度比现有长",
			[]*Range{{100, 100}},
			300,
			[]*Range{{100, 100}},
		},
		{
			"截断的长度等于现有长",
			[]*Range{{100, 100}},
			200,
			[]*Range{{100, 100}},
		},
		{
			"截断的长度小于现有长",
			[]*Range{{100, 100}, {300, 100}},
			150,
			[]*Range{{100, 50}},
		},
		{
			"截断了所有",
			[]*Range{{100, 100}, {300, 100}},
			0,
			[]*Range{},
		},
		{
			"截断的位置在空洞内",
			[]*Range{{100, 100}, {300, 100}},
			250,
			[]*Range{{100, 100}},
		},
	}

	for _, c := range cases {
		Convey(c.title, t, func() {
			got := TruncateRange(c.arr, c.pos)
			So(got, ShouldResemble, c.want)
		})
	}
}

func Test_DifferentRange(t *testing.T) {
	cases := []struct {
		title string
		rng   *Range
		arr   []*Range
		want  *Range
	}{
		{
			"空数组",
			&Range{100, 100},
			[]*Range{},
			&Range{100, 100},
		},
		{
			"区间的右边被截断",
			&Range{50, 150},
			[]*Range{{100, 100}, {300, 100}},
			&Range{50, 50},
		},
		{
			"区间的左边被截断",
			&Range{150, 150},
			[]*Range{{100, 100}, {300, 100}},
			&Range{200, 100},
		},
		{
			"区间被彻底截断",
			&Range{100, 100},
			[]*Range{{100, 100}, {300, 100}},
			&Range{200, 0},
		},
		{
			"区间被截断成多份1",
			&Range{0, 400},
			[]*Range{{100, 100}, {300, 100}},
			&Range{0, 100},
		},
		{
			"区间被截断成多份2",
			&Range{100, 300},
			[]*Range{{100, 100}, {300, 100}},
			&Range{200, 100},
		},
	}

	for _, c := range cases {
		Convey(c.title, t, func() {
			DifferentRange(c.rng, c.arr)
			So(c.rng, ShouldResemble, c.want)
		})
	}
}