package util

import (
	"bytes"
	"encoding/base64"
	"os"
	"path/filepath"
	"regexp"

	. "github.com/onsi/ginkgo"
	"github.com/onsi/ginkgo/extensions/table"
	. "github.com/onsi/gomega"

	"k8s.io/apimachinery/pkg/api/resource"
)

const (
	pattern       = "^[a-zA-Z0-9]+$"
	TestImagesDir = "../../tests/images"
)

var (
	fileDir, _ = filepath.Abs(TestImagesDir)
)

var _ = Describe("Util", func() {
	It("Should match RandAlphaNum", func() {
		got := RandAlphaNum(8)
		Expect(len(got)).To(Equal(8))
		Expect(regexp.MustCompile(pattern).Match([]byte(got))).To(BeTrue())
	})

	table.DescribeTable("Round down", func(input, multiple, expectedResult int64) {
		result := RoundDown(input, multiple)
		Expect(result).To(Equal(expectedResult))
	},
		table.Entry("Round down 513 to nearest multiple of 512", int64(513), int64(512), int64(512)),
		table.Entry("Round down 512 to nearest multiple of 512", int64(512), int64(512), int64(512)),
		table.Entry("Round down 510 to nearest multiple of 512", int64(510), int64(512), int64(0)),
		table.Entry("Round down 0 to nearest multiple of 512", int64(0), int64(512), int64(0)),
		table.Entry("Round down 513 to nearest multiple of 2", int64(513), int64(2), int64(512)),
		table.Entry("Round down 512 to nearest multiple of 2", int64(512), int64(2), int64(512)),
		table.Entry("Round down 510 to nearest multiple of 2", int64(510), int64(2), int64(510)),
	)

	table.DescribeTable("Round up", func(input, multiple, expectedResult int64) {
		result := RoundUp(input, multiple)
		Expect(result).To(Equal(expectedResult))
	},
		table.Entry("Round up 513 to nearest multiple of 512", int64(513), int64(512), int64(1024)),
		table.Entry("Round up 512 to nearest multiple of 512", int64(512), int64(512), int64(512)),
		table.Entry("Round up 510 to nearest multiple of 512", int64(510), int64(512), int64(512)),
		table.Entry("Round up 0 to nearest multiple of 512", int64(0), int64(512), int64(0)),
		table.Entry("Round up 513 to nearest multiple of 2", int64(513), int64(2), int64(514)),
		table.Entry("Round up 512 to nearest multiple of 2", int64(512), int64(2), int64(512)),
		table.Entry("Round up 510 to nearest multiple of 2", int64(510), int64(2), int64(510)),
	)

	table.DescribeTable("Find Namespace", func(inputFile, expectedResult string) {
		result := getNamespace(inputFile)
		Expect(result).To(Equal(expectedResult))
	},
		table.Entry("Valid namespace", filepath.Join(fileDir, "namespace.txt"), "test-namespace"),
		table.Entry("Invalid file", "doesnotexist", "cdi"),
	)
})

var _ = Describe("GetNameSpace", func() {
	It("Report default namespace outside container", func() {
		Expect("cdi").To(Equal(GetNamespace()))
	})
})

var _ = Describe("ParseEnv", func() {
	BeforeEach(func() {
		os.Setenv("value1", "value1")
		os.Setenv("value2", base64.StdEncoding.EncodeToString([]byte("value2")))
		os.Setenv("value3", "invalid --- *** &&&")
	})

	AfterEach(func() {
		os.Unsetenv("value1")
		os.Unsetenv("value2")
		os.Unsetenv("value3")
	})

	It("Parse environment unencoded variables", func() {
		result, err := ParseEnvVar("value1", false)
		Expect(result).To(Equal("value1"))
		Expect(err).ToNot(HaveOccurred())
		result, err = ParseEnvVar("value1", true)
		Expect(result).ToNot(Equal("value1"))
		Expect(err).To(HaveOccurred())

		result, err = ParseEnvVar("value2", false)
		Expect(result).ToNot(Equal("value2"))
		Expect(err).ToNot(HaveOccurred())
		result, err = ParseEnvVar("value2", true)
		Expect(result).To(Equal("value2"))
		Expect(err).ToNot(HaveOccurred())

		_, err = ParseEnvVar("value3", true)
		Expect(err).To(HaveOccurred())
	})
})

var _ = Describe("Compare quantities", func() {
	It("Should properly compare quantities", func() {
		small := resource.NewScaledQuantity(int64(1000), 0)
		big := resource.NewScaledQuantity(int64(10000), 0)
		result := MinQuantity(small, big)
		Expect(result).To(Equal(*small))
		result = MinQuantity(big, small)
		Expect(result).To(Equal(*small))
	})
})

var _ = Describe("Copy files", func() {
	var destTmp string
	var err error

	BeforeEach(func() {
		destTmp, err = os.MkdirTemp("", "dest")
		Expect(err).NotTo(HaveOccurred())
	})

	AfterEach(func() {
		err = os.RemoveAll(destTmp)
		Expect(err).NotTo(HaveOccurred())
		os.Remove("test.txt")
	})

	It("Should copy file from source to dest, with valid source and dest", func() {
		err = CopyFile(filepath.Join(TestImagesDir, "content.tar"), filepath.Join(destTmp, "target.tar"))
		Expect(err).ToNot(HaveOccurred())
		sourceMd5, err := Md5sum(filepath.Join(TestImagesDir, "content.tar"))
		Expect(err).ToNot(HaveOccurred())
		targetMd5, err := Md5sum(filepath.Join(destTmp, "target.tar"))
		Expect(err).ToNot(HaveOccurred())
		Expect(sourceMd5).Should(Equal(targetMd5))
	})

	It("Should not copy file from source to dest, with invalid source", func() {
		err = CopyFile(filepath.Join(TestImagesDir, "content.tar22"), filepath.Join(destTmp, "target.tar"))
		Expect(err).To(HaveOccurred())
	})

	It("Should not copy file from source to dest, with invalid target", func() {
		err = CopyFile(filepath.Join(TestImagesDir, "content.tar"), filepath.Join("/invalidpath", "target.tar"))
		Expect(err).To(HaveOccurred())
	})
})

var _ = Describe("Zero out ranges in files", func() {
	var testFile *os.File
	var testData []byte
	testData = append(testData, bytes.Repeat([]byte{0x55}, 1024)...)
	testData = append(testData, bytes.Repeat([]byte{0xAA}, 1024)...)
	testData = append(testData, bytes.Repeat([]byte{0xFF}, 1024)...)

	BeforeEach(func() {
		var err error

		testFile, err = os.CreateTemp("", "test")
		Expect(err).ToNot(HaveOccurred())
		written, err := testFile.Write(testData)
		Expect(err).ToNot(HaveOccurred())
		Expect(written).To(Equal(len(testData)))
	})

	AfterEach(func() {
		testFile.Close()
		os.Remove(testFile.Name())
	})

	It("Should successfully zero a range with fallocate", func() {
		start := 512
		length := 100
		end := start + length
		err := PunchHole(testFile, int64(start), int64(length))
		Expect(err).ToNot(HaveOccurred())
		err = testFile.Sync()
		Expect(err).ToNot(HaveOccurred())
		err = testFile.Close()
		Expect(err).ToNot(HaveOccurred())
		data, err := os.ReadFile(testFile.Name())
		Expect(err).ToNot(HaveOccurred())
		Expect(len(data)).To(Equal(len(testData)))
		comparison := bytes.Compare(data[start:end], bytes.Repeat([]byte{0}, length))
		Expect(comparison).To(Equal(0))
		comparison = bytes.Compare(data[0:start], testData[0:start])
		Expect(comparison).To(Equal(0))
		comparison = bytes.Compare(data[end:], testData[end:])
		Expect(comparison).To(Equal(0))
	})

	table.DescribeTable("Should successfully append zeroes to a file", func(appendFunction func(f *os.File, start, length int64) error) {
		length := 1024
		err := appendFunction(testFile, int64(len(testData)), int64(length))
		Expect(err).ToNot(HaveOccurred())
		err = testFile.Sync()
		Expect(err).ToNot(HaveOccurred())
		err = testFile.Close()
		Expect(err).ToNot(HaveOccurred())
		data, err := os.ReadFile(testFile.Name())
		Expect(err).ToNot(HaveOccurred())
		Expect(len(data)).To(Equal(len(testData) + length))
		comparison := bytes.Compare(data[:len(testData)], testData)
		Expect(comparison).To(Equal(0))
		comparison = bytes.Compare(data[len(testData):], bytes.Repeat([]byte{0}, length))
		Expect(comparison).To(Equal(0))
	},
		table.Entry("using truncate", AppendZeroWithTruncate),
		table.Entry("using write", AppendZeroWithWrite),
	)

	table.DescribeTable("Should fail to append zeroes to a file using seek if it already has data at the specified starting index", func(appendFunction func(f *os.File, start, length int64) error) {
		length := 1024
		err := appendFunction(testFile, 0, int64(length))
		Expect(err).To(HaveOccurred())
		Expect(err.Error()).Should(MatchRegexp(".*cannot safely append.*"))
	},
		table.Entry("using truncate", AppendZeroWithTruncate),
		table.Entry("using write", AppendZeroWithWrite),
	)
})
var _ = Describe("Usable Space calculation", func() {

	const (
		Mi              = int64(1024 * 1024)
		Gi              = 1024 * Mi
		noOverhead      = float64(0)
		defaultOverhead = float64(0.055)
		largeOverhead   = float64(0.75)
	)
	table.DescribeTable("getusablespace should return properly aligned sizes,", func(virtualSize int64, overhead float64) {
		for i := int64(virtualSize - 1024); i < virtualSize+1024; i++ {
			// Requested space is virtualSize rounded up to 1Mi alignment / (1 - overhead) rounded up
			requestedSpace := int64(float64(RoundUp(i, DefaultAlignBlockSize)+1) / float64(1-overhead))
			if i <= virtualSize {
				Expect(GetUsableSpace(overhead, requestedSpace)).To(Equal(virtualSize))
			} else {
				Expect(GetUsableSpace(overhead, requestedSpace)).To(Equal(virtualSize + Mi))
			}
		}
	},
		table.Entry("1Mi virtual size, 0 overhead to be 1Mi if <= 1Mi and 2Mi if > 1Mi", Mi, noOverhead),
		table.Entry("1Mi virtual size, default overhead to be 1Mi if <= 1Mi and 2Mi if > 1Mi", Mi, defaultOverhead),
		table.Entry("1Mi virtual size, large overhead to be 1Mi if <= 1Mi and 2Mi if > 1Mi", Mi, largeOverhead),
		table.Entry("40Mi virtual size, 0 overhead to be 40Mi if <= 1Mi and 41Mi if > 40Mi", 40*Mi, noOverhead),
		table.Entry("40Mi virtual size, default overhead to be 40Mi if <= 1Mi and 41Mi if > 40Mi", 40*Mi, defaultOverhead),
		table.Entry("40Mi virtual size, large overhead to be 40Mi if <= 40Mi and 41Mi if > 40Mi", 40*Mi, largeOverhead),
		table.Entry("1Gi virtual size, 0 overhead to be 1Gi if <= 1Gi and 2Gi if > 1Gi", Gi, noOverhead),
		table.Entry("1Gi virtual size, default overhead to be 1Gi if <= 1Gi and 2Gi if > 1Gi", Gi, defaultOverhead),
		table.Entry("1Gi virtual size, large overhead to be 1Gi if <= 1Gi and 2Gi if > 1Gi", Gi, largeOverhead),
		table.Entry("40Gi virtual size, 0 overhead to be 40Gi if <= 1Gi and 41Gi if > 40Gi", 40*Gi, noOverhead),
		table.Entry("40Gi virtual size, default overhead to be 40Gi if <= 1Gi and 41Gi if > 40Gi", 40*Gi, defaultOverhead),
		table.Entry("40Gi virtual size, large overhead to be 40Gi if <= 40Gi and 41Gi if > 40Gi", 40*Gi, largeOverhead),
	)
})