// Copyright © 2019 Ettore Di Giacinto <mudler@gentoo.org>
//
// This program is free software; you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation; either version 2 of the License, or
// (at your option) any later version.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License along
// with this program; if not, see <http://www.gnu.org/licenses/>.

package compiler

import (
	"archive/tar"
	"bufio"
	"io"
	"io/ioutil"
	"os"
	"path"
	"path/filepath"
	"regexp"

	gzip "github.com/klauspost/pgzip"

	//"strconv"
	"strings"
	"sync"

	"github.com/mudler/luet/pkg/helpers"
	. "github.com/mudler/luet/pkg/logger"
	"github.com/mudler/luet/pkg/solver"
	"github.com/pkg/errors"
	yaml "gopkg.in/yaml.v2"
)

type CompressionImplementation string

const (
	None CompressionImplementation = "none" // e.g. tar for standard packages
	GZip CompressionImplementation = "gzip"
)

type ArtifactIndex []Artifact

func (i ArtifactIndex) CleanPath() ArtifactIndex {
	newIndex := ArtifactIndex{}
	for _, n := range i {
		art := n.(*PackageArtifact)
		// FIXME: This is a dup and makes difficult to add attributes to artifacts
		newIndex = append(newIndex, &PackageArtifact{
			Path:            path.Base(n.GetPath()),
			SourceAssertion: art.SourceAssertion,
			CompileSpec:     art.CompileSpec,
			Dependencies:    art.Dependencies,
			CompressionType: art.CompressionType,
			Checksums:       art.Checksums,
		})
	}
	return newIndex
	//Update if exists, otherwise just create
}

//  When compiling, we write also a fingerprint.metadata.yaml file with PackageArtifact. In this way we can have another command to create the repository
// which will consist in just of an repository.yaml which is just the repository structure with the list of package artifact.
// In this way a generic client can fetch the packages and, after unpacking the tree, performing queries to install packages.
type PackageArtifact struct {
	Path string `json:"path"`

	Dependencies    []*PackageArtifact        `json:"dependencies"`
	CompileSpec     *LuetCompilationSpec      `json:"compilationspec"`
	Checksums       Checksums                 `json:"checksums"`
	SourceAssertion solver.PackagesAssertions `json:"-"`
	CompressionType CompressionImplementation `json:"compressiontype"`
}

func NewPackageArtifact(path string) Artifact {
	return &PackageArtifact{Path: path, Dependencies: []*PackageArtifact{}, Checksums: Checksums{}, CompressionType: None}
}

func NewPackageArtifactFromYaml(data []byte) (Artifact, error) {
	p := &PackageArtifact{Checksums: Checksums{}}
	err := yaml.Unmarshal(data, &p)
	if err != nil {
		return p, err
	}

	return p, err
}

func LoadArtifactFromYaml(spec CompilationSpec) (Artifact, error) {

	metaFile := spec.GetPackage().GetFingerPrint() + ".metadata.yaml"
	dat, err := ioutil.ReadFile(spec.Rel(metaFile))
	if err != nil {
		return nil, errors.Wrap(err, "Error reading file "+metaFile)
	}

	return NewPackageArtifactFromYaml(dat)
}

func (a *PackageArtifact) SetCompressionType(t CompressionImplementation) {
	a.CompressionType = t
}

func (a *PackageArtifact) Hash() error {
	return a.Checksums.Generate(a)
}

func (a *PackageArtifact) Verify() error {
	sum := Checksums{}
	err := sum.Generate(a)
	if err != nil {
		return err
	}
	err = sum.Compare(a.Checksums)
	if err != nil {
		return err
	}
	return nil
}

func (a *PackageArtifact) WriteYaml(dst string) error {
	// First compute checksum of artifact. When we write the yaml we want to write up-to-date informations.
	err := a.Hash()
	if err != nil {
		return errors.Wrap(err, "Failed generating checksums for artifact")
	}

	//p := a.CompileSpec.GetPackage().GetPath()

	//a.CompileSpec.GetPackage().SetPath("")
	//	for _, ass := range a.CompileSpec.GetSourceAssertion() {
	//		ass.Package.SetPath("")
	//	}
	data, err := yaml.Marshal(a)
	if err != nil {
		return errors.Wrap(err, "While marshalling for PackageArtifact YAML")
	}

	mangle, err := NewPackageArtifactFromYaml(data)
	if err != nil {
		return errors.Wrap(err, "Generated invalid artifact")
	}
	//p := a.CompileSpec.GetPackage().GetPath()

	mangle.GetCompileSpec().GetPackage().SetPath("")
	for _, ass := range mangle.GetCompileSpec().GetSourceAssertion() {
		ass.Package.SetPath("")
	}

	data, err = yaml.Marshal(mangle)
	if err != nil {
		return errors.Wrap(err, "While marshalling for PackageArtifact YAML")
	}

	err = ioutil.WriteFile(filepath.Join(dst, a.GetCompileSpec().GetPackage().GetFingerPrint()+".metadata.yaml"), data, os.ModePerm)
	if err != nil {
		return errors.Wrap(err, "While writing PackageArtifact YAML")
	}
	//a.CompileSpec.GetPackage().SetPath(p)

	return nil
}

func (a *PackageArtifact) GetSourceAssertion() solver.PackagesAssertions {
	return a.SourceAssertion
}

func (a *PackageArtifact) SetCompileSpec(as CompilationSpec) {
	a.CompileSpec = as.(*LuetCompilationSpec)
}

func (a *PackageArtifact) GetCompileSpec() CompilationSpec {
	return a.CompileSpec
}

func (a *PackageArtifact) SetSourceAssertion(as solver.PackagesAssertions) {
	a.SourceAssertion = as
}

func (a *PackageArtifact) GetDependencies() []Artifact {
	ret := []Artifact{}
	for _, d := range a.Dependencies {
		ret = append(ret, d)
	}
	return ret
}

func (a *PackageArtifact) SetDependencies(d []Artifact) {
	ret := []*PackageArtifact{}
	for _, dd := range d {
		ret = append(ret, dd.(*PackageArtifact))
	}
	a.Dependencies = ret
}

func (a *PackageArtifact) GetPath() string {
	return a.Path
}

func (a *PackageArtifact) SetPath(p string) {
	a.Path = p
}

// Compress Archives and compress (TODO) to the artifact path
func (a *PackageArtifact) Compress(src string, concurrency int) error {
	switch a.CompressionType {
	case GZip:
		err := helpers.Tar(src, a.Path)
		if err != nil {
			return err
		}
		original, err := os.Open(a.Path)
		if err != nil {
			return err
		}
		defer original.Close()

		gzipfile := a.Path + ".gz"
		bufferedReader := bufio.NewReader(original)

		// Open a file for writing.
		dst, err := os.Create(gzipfile)
		if err != nil {
			return err
		}
		// Create gzip writer.
		w := gzip.NewWriter(dst)
		w.SetConcurrency(concurrency, 10)
		defer w.Close()
		defer dst.Close()
		_, err = io.Copy(w, bufferedReader)
		if err != nil {
			return err
		}
		w.Close()
		os.RemoveAll(a.Path) // Remove original
		//	a.CompressedPath = gzipfile
		a.Path = gzipfile
		return nil
		//a.Path = gzipfile

	// Defaults to tar only (covers when "none" is supplied)
	default:
		return helpers.Tar(src, a.Path)

	}
	return errors.New("Compression type must be supplied")
}

// Unpack Untar and decompress (TODO) to the given path
func (a *PackageArtifact) Unpack(dst string, keepPerms bool) error {
	switch a.CompressionType {
	case GZip:
		// Create the uncompressed archive
		archive, err := os.Create(a.GetPath() + ".uncompressed")
		if err != nil {
			return err
		}
		defer os.RemoveAll(a.GetPath() + ".uncompressed")
		defer archive.Close()

		original, err := os.Open(a.Path)
		if err != nil {
			return errors.Wrap(err, "Cannot open "+a.Path)
		}
		defer original.Close()

		bufferedReader := bufio.NewReader(original)
		r, err := gzip.NewReader(bufferedReader)
		if err != nil {
			return err
		}
		defer r.Close()

		_, err = io.Copy(archive, r)
		if err != nil {
			return errors.Wrap(err, "Cannot copy to "+a.GetPath()+".uncompressed")
		}

		err = helpers.Untar(a.GetPath()+".uncompressed", dst, keepPerms)
		if err != nil {
			return err
		}
		return nil
	// Defaults to tar only (covers when "none" is supplied)
	default:
		return helpers.Untar(a.GetPath(), dst, keepPerms)
	}
	return errors.New("Compression type must be supplied")
}

func (a *PackageArtifact) FileList() ([]string, error) {
	var tr *tar.Reader
	switch a.CompressionType {
	case GZip:
		// Create the uncompressed archive
		archive, err := os.Create(a.GetPath() + ".uncompressed")
		if err != nil {
			return []string{}, err
		}
		defer os.RemoveAll(a.GetPath() + ".uncompressed")
		defer archive.Close()

		original, err := os.Open(a.Path)
		if err != nil {
			return []string{}, errors.Wrap(err, "Cannot open "+a.Path)
		}
		defer original.Close()

		bufferedReader := bufio.NewReader(original)
		r, err := gzip.NewReader(bufferedReader)
		if err != nil {
			return []string{}, err
		}
		defer r.Close()
		tr = tar.NewReader(r)

	// Defaults to tar only (covers when "none" is supplied)
	default:
		tarFile, err := os.Open(a.GetPath())
		if err != nil {
			return []string{}, errors.Wrap(err, "Could not open package archive")
		}
		defer tarFile.Close()
		tr = tar.NewReader(tarFile)

	}

	var files []string
	// untar each segment
	for {
		hdr, err := tr.Next()
		if err == io.EOF {
			break
		}
		if err != nil {
			return []string{}, err
		}
		// determine proper file path info
		finfo := hdr.FileInfo()
		fileName := hdr.Name
		if finfo.Mode().IsDir() {
			continue
		}
		files = append(files, fileName)

		// if a dir, create it, then go to next segment
	}
	return files, nil
}

type CopyJob struct {
	Src, Dst string
	Artifact string
}

func worker(i int, wg *sync.WaitGroup, s <-chan CopyJob) {
	defer wg.Done()

	for job := range s {
		//Info("#"+strconv.Itoa(i), "copying", job.Src, "to", job.Dst)
		// if dir, err := helpers.IsDirectory(job.Src); err == nil && dir {
		// 	err = helpers.CopyDir(job.Src, job.Dst)
		// 	if err != nil {
		// 		Warning("Error copying dir", job, err)
		// 	}
		// 	continue
		// }

		if !helpers.Exists(job.Dst) {
			if err := helpers.CopyFile(job.Src, job.Dst); err != nil {
				Warning("Error copying", job, err)
			}
		}
	}
}

// ExtractArtifactFromDelta extracts deltas from ArtifactLayer from an image in tar format
func ExtractArtifactFromDelta(src, dst string, layers []ArtifactLayer, concurrency int, keepPerms bool, includes []string, t CompressionImplementation) (Artifact, error) {

	archive, err := ioutil.TempDir(os.TempDir(), "archive")
	if err != nil {
		return nil, errors.Wrap(err, "Error met while creating tempdir for archive")
	}
	defer os.RemoveAll(archive) // clean up

	if strings.HasSuffix(src, ".tar") {
		rootfs, err := ioutil.TempDir(os.TempDir(), "rootfs")
		if err != nil {
			return nil, errors.Wrap(err, "Error met while creating tempdir for rootfs")
		}
		defer os.RemoveAll(rootfs) // clean up
		err = helpers.Untar(src, rootfs, keepPerms)
		if err != nil {
			return nil, errors.Wrap(err, "Error met while unpacking rootfs")
		}
		src = rootfs
	}

	toCopy := make(chan CopyJob)

	var wg = new(sync.WaitGroup)
	for i := 0; i < concurrency; i++ {
		wg.Add(1)
		go worker(i, wg, toCopy)
	}

	// Handle includes in spec. If specified they filter what gets in the package
	if len(includes) > 0 {
		var includeRegexp []*regexp.Regexp
		for _, i := range includes {
			r, e := regexp.Compile(i)
			if e != nil {
				Warning("Failed compiling regex:", e)
				continue
			}
			includeRegexp = append(includeRegexp, r)
		}
		for _, l := range layers {
			// Consider d.Additions (and d.Changes? - warn at least) only
		ADDS:
			for _, a := range l.Diffs.Additions {
				for _, i := range includeRegexp {
					if i.MatchString(a.Name) {
						toCopy <- CopyJob{Src: filepath.Join(src, a.Name), Dst: filepath.Join(archive, a.Name), Artifact: a.Name}
						continue ADDS
					}
				}
			}
		}
	} else {
		// Otherwise just grab all
		for _, l := range layers {
			// Consider d.Additions (and d.Changes? - warn at least) only
			for _, a := range l.Diffs.Additions {
				toCopy <- CopyJob{Src: filepath.Join(src, a.Name), Dst: filepath.Join(archive, a.Name), Artifact: a.Name}
			}
		}
	}

	close(toCopy)
	wg.Wait()
	a := NewPackageArtifact(dst)
	a.SetCompressionType(t)
	err = a.Compress(archive, concurrency)
	if err != nil {
		return nil, errors.Wrap(err, "Error met while creating package archive")
	}
	return a, nil
}