package deb

import (
	"bytes"
	"fmt"
	"io"
	"os"
	"path/filepath"
	"sort"
	"strings"
	"sync"
	"text/template"

	"github.com/aptly-dev/aptly/aptly"
	"github.com/aptly-dev/aptly/pgp"
	"github.com/aptly-dev/aptly/utils"
	"github.com/saracen/walker"
)

// Changes is a result of .changes file parsing
type Changes struct {
	Changes               string
	Distribution          string
	Files                 PackageFiles
	BasePath, ChangesName string
	TempDir               string
	Source                string
	Binary                []string
	Architectures         []string
	Stanza                Stanza
	SignatureKeys         []pgp.Key
}

// NewChanges moves .changes file into temporary directory and creates Changes structure
func NewChanges(path string) (*Changes, error) {
	var err error

	c := &Changes{
		BasePath:    filepath.Dir(path),
		ChangesName: filepath.Base(path),
	}

	c.TempDir, err = os.MkdirTemp(os.TempDir(), "aptly")
	if err != nil {
		return nil, err
	}

	// copy .changes file into temporary directory
	err = utils.CopyFile(filepath.Join(c.BasePath, c.ChangesName), filepath.Join(c.TempDir, c.ChangesName))
	if err != nil {
		return nil, err
	}

	return c, nil
}

// VerifyAndParse does optional signature verification and parses changes files
func (c *Changes) VerifyAndParse(acceptUnsigned, ignoreSignature bool, verifier pgp.Verifier) error {
	input, err := os.Open(filepath.Join(c.TempDir, c.ChangesName))
	if err != nil {
		return err
	}
	defer func() { _ = input.Close() }()

	isClearSigned, err := verifier.IsClearSigned(input)
	if err != nil {
		return err
	}

	_, _ = input.Seek(0, 0)

	if !isClearSigned && !acceptUnsigned {
		return fmt.Errorf(".changes file is not signed and unsigned processing hasn't been enabled")
	}

	if isClearSigned && !ignoreSignature {
		var keyInfo *pgp.KeyInfo
		keyInfo, err = verifier.VerifyClearsigned(input, false)
		if err != nil {
			return err
		}
		_, _ = input.Seek(0, 0)

		c.SignatureKeys = keyInfo.GoodKeys
	}

	var text io.ReadCloser

	if isClearSigned {
		text, err = verifier.ExtractClearsigned(input)
		if err != nil {
			return err
		}
		defer func() { _ = text.Close() }()
	} else {
		text = input
	}

	reader := NewControlFileReader(text, false, false)
	c.Stanza, err = reader.ReadStanza()
	if err != nil {
		return err
	}

	c.Distribution = c.Stanza["Distribution"]
	c.Changes = c.Stanza["Changes"]
	c.Source = c.Stanza["Source"]
	c.Binary = strings.Fields(c.Stanza["Binary"])
	c.Architectures = strings.Fields(c.Stanza["Architecture"])

	c.Files, err = c.Files.ParseSumFields(c.Stanza)
	return err
}

// Prepare creates temporary directory, copies file there and verifies checksums
func (c *Changes) Prepare() error {
	var err error

	for _, file := range c.Files {
		if filepath.Dir(file.Filename) != "." {
			return fmt.Errorf("file is not in the same folder as .changes file: %s", file.Filename)
		}

		file.Filename = filepath.Base(file.Filename)

		err = utils.CopyFile(filepath.Join(c.BasePath, file.Filename), filepath.Join(c.TempDir, file.Filename))
		if err != nil {
			return err
		}
	}

	for _, file := range c.Files {
		var info utils.ChecksumInfo

		info, err = utils.ChecksumsForFile(filepath.Join(c.TempDir, file.Filename))
		if err != nil {
			return err
		}

		if info.Size != file.Checksums.Size {
			return fmt.Errorf("size mismatch: expected %v != obtained %v", file.Checksums.Size, info.Size)
		}

		if info.MD5 != file.Checksums.MD5 {
			return fmt.Errorf("checksum mismatch MD5: expected %v != obtained %v", file.Checksums.MD5, info.MD5)
		}

		if info.SHA1 != file.Checksums.SHA1 {
			return fmt.Errorf("checksum mismatch SHA1: expected %v != obtained %v", file.Checksums.SHA1, info.SHA1)
		}

		if info.SHA256 != file.Checksums.SHA256 {
			return fmt.Errorf("checksum mismatch SHA256 expected %v != obtained %v", file.Checksums.SHA256, info.SHA256)
		}
	}

	return nil
}

// Cleanup removes all temporary files
func (c *Changes) Cleanup() error {
	if c.TempDir == "" {
		return nil
	}

	return os.RemoveAll(c.TempDir)
}

// PackageQuery returns query that every package should match to be included
func (c *Changes) PackageQuery() PackageQuery {
	var archQuery PackageQuery = &FieldQuery{Field: "$Architecture", Relation: VersionEqual, Value: ""}
	for _, arch := range c.Architectures {
		archQuery = &OrQuery{L: &FieldQuery{Field: "$Architecture", Relation: VersionEqual, Value: arch}, R: archQuery}
	}

	// if c.Source is empty, this would never match
	sourceQuery := &AndQuery{
		L: &FieldQuery{Field: "$PackageType", Relation: VersionEqual, Value: ArchitectureSource},
		R: &FieldQuery{Field: "Name", Relation: VersionEqual, Value: c.Source},
	}

	var binaryQuery PackageQuery
	if len(c.Binary) > 0 {
		binaryQuery = &FieldQuery{Field: "Name", Relation: VersionEqual, Value: c.Binary[0]}
		// matching debug ddeb packages, they're not present in the Binary field
		var ddebQuery PackageQuery = &FieldQuery{Field: "Name", Relation: VersionEqual, Value: fmt.Sprintf("%s-dbgsym", c.Binary[0])}

		for _, binary := range c.Binary[1:] {
			binaryQuery = &OrQuery{
				L: &FieldQuery{Field: "Name", Relation: VersionEqual, Value: binary},
				R: binaryQuery,
			}
			ddebQuery = &OrQuery{
				L: &FieldQuery{Field: "Name", Relation: VersionEqual, Value: fmt.Sprintf("%s-dbgsym", binary)},
				R: ddebQuery,
			}
		}

		binaryQuery = &OrQuery{
			L: binaryQuery,
			R: ddebQuery,
		}

		binaryQuery = &AndQuery{
			L: &NotQuery{Q: &FieldQuery{Field: "$PackageType", Relation: VersionEqual, Value: ArchitectureSource}},
			R: binaryQuery}
	}

	var nameQuery PackageQuery
	if binaryQuery == nil {
		nameQuery = sourceQuery
	} else {
		nameQuery = &OrQuery{L: sourceQuery, R: binaryQuery}
	}

	return &AndQuery{L: archQuery, R: nameQuery}
}

// GetField implements PackageLike interface
func (c *Changes) GetField(field string) string {
	return c.Stanza[field]
}

// MatchesDependency implements PackageLike interface
func (c *Changes) MatchesDependency(_ Dependency) bool {
	return false
}

// MatchesArchitecture implements PackageLike interface
func (c *Changes) MatchesArchitecture(_ string) bool {
	return false
}

// GetName implements PackageLike interface
func (c *Changes) GetName() string {
	return ""
}

// GetVersion implements PackageLike interface
func (c *Changes) GetVersion() string {
	return ""

}

// GetArchitecture implements PackageLike interface
func (c *Changes) GetArchitecture() string {
	return ""
}

// CollectChangesFiles walks filesystem collecting all .changes files
func CollectChangesFiles(locations []string, reporter aptly.ResultReporter) (changesFiles, failedFiles []string) {
	changesFilesLock := &sync.Mutex{}

	for _, location := range locations {
		info, err2 := os.Stat(location)
		if err2 != nil {
			reporter.Warning("Unable to process %s: %s", location, err2)
			failedFiles = append(failedFiles, location)
			continue
		}
		if info.IsDir() {
			err2 = walker.Walk(location, func(path string, info os.FileInfo) error {
				if info.IsDir() {
					return nil
				}

				if strings.HasSuffix(info.Name(), ".changes") {
					changesFilesLock.Lock()
					defer changesFilesLock.Unlock()
					changesFiles = append(changesFiles, path)
				}

				return nil
			})

			if err2 != nil {
				reporter.Warning("Unable to process %s: %s", location, err2)
				failedFiles = append(failedFiles, location)
				continue
			}
		} else if strings.HasSuffix(info.Name(), ".changes") {
			changesFiles = append(changesFiles, location)
		}
	}

	sort.Strings(changesFiles)

	return
}

// ImportChangesFiles imports referenced files in changes files into local repository
func ImportChangesFiles(changesFiles []string, reporter aptly.ResultReporter, acceptUnsigned, ignoreSignatures, forceReplace, noRemoveFiles bool,
	verifier pgp.Verifier, repoTemplate *template.Template, progress aptly.Progress, localRepoCollection *LocalRepoCollection, packageCollection *PackageCollection,
	pool aptly.PackagePool, checksumStorageProvider aptly.ChecksumStorageProvider, uploaders *Uploaders, parseQuery parseQuery) (processedFiles []string, failedFiles []string, err error) {

	for _, path := range changesFiles {
		var changes *Changes

		changes, err = NewChanges(path)
		if err != nil {
			failedFiles = append(failedFiles, path)
			reporter.Warning("unable to process file %s: %s", path, err)
			continue
		}

		err = changes.VerifyAndParse(acceptUnsigned, ignoreSignatures, verifier)
		if err != nil {
			failedFiles = append(failedFiles, path)
			reporter.Warning("unable to process file %s: %s", changes.ChangesName, err)
			_ = changes.Cleanup()
			continue
		}

		err = changes.Prepare()
		if err != nil {
			failedFiles = append(failedFiles, path)
			reporter.Warning("unable to process file %s: %s", changes.ChangesName, err)
			_ = changes.Cleanup()
			continue
		}

		repoName := &bytes.Buffer{}
		err = repoTemplate.Execute(repoName, changes.Stanza)
		if err != nil {
			return nil, nil, fmt.Errorf("error applying template to repo: %s", err)
		}

		if progress != nil {
			progress.Printf("Loading repository %s for changes file %s...\n", repoName.String(), changes.ChangesName)
		}

		var repo *LocalRepo
		repo, err = localRepoCollection.ByName(repoName.String())
		if err != nil {
			failedFiles = append(failedFiles, path)
			reporter.Warning("unable to process file %s: %s", changes.ChangesName, err)
			_ = changes.Cleanup()
			continue
		}

		currentUploaders := uploaders
		if repo.Uploaders != nil {
			currentUploaders = repo.Uploaders
			for i := range currentUploaders.Rules {
				currentUploaders.Rules[i].CompiledCondition, err = parseQuery(currentUploaders.Rules[i].Condition)
				if err != nil {
					return nil, nil, fmt.Errorf("error parsing query %s: %s", currentUploaders.Rules[i].Condition, err)
				}
			}
		}

		if currentUploaders != nil {
			if err = currentUploaders.IsAllowed(changes); err != nil {
				failedFiles = append(failedFiles, path)
				reporter.Warning("changes file skipped due to uploaders config: %s, keys %#v: %s",
					changes.ChangesName, changes.SignatureKeys, err)
				_ = changes.Cleanup()
				continue
			}
		}

		err = localRepoCollection.LoadComplete(repo)
		if err != nil {
			return nil, nil, fmt.Errorf("unable to load repo: %s", err)
		}

		var list *PackageList
		list, err = NewPackageListFromRefList(repo.RefList(), packageCollection, progress)
		if err != nil {
			return nil, nil, fmt.Errorf("unable to load packages: %s", err)
		}

		packageFiles, otherFiles, _ := CollectPackageFiles([]string{changes.TempDir}, reporter)

		restriction := changes.PackageQuery()
		var processedFiles2, failedFiles2 []string

		processedFiles2, failedFiles2, err = ImportPackageFiles(list, packageFiles, forceReplace, verifier, pool,
			packageCollection, reporter, restriction, checksumStorageProvider)

		if err != nil {
			return nil, nil, fmt.Errorf("unable to import package files: %s", err)
		}

		repo.UpdateRefList(NewPackageRefListFromPackageList(list))

		err = localRepoCollection.Update(repo)
		if err != nil {
			return nil, nil, fmt.Errorf("unable to save: %s", err)
		}

		err = changes.Cleanup()
		if err != nil {
			return nil, nil, err
		}

		for _, file := range failedFiles2 {
			failedFiles = append(failedFiles, filepath.Join(changes.BasePath, filepath.Base(file)))
		}

		for _, file := range processedFiles2 {
			processedFiles = append(processedFiles, filepath.Join(changes.BasePath, filepath.Base(file)))
		}

		for _, file := range otherFiles {
			processedFiles = append(processedFiles, filepath.Join(changes.BasePath, filepath.Base(file)))
		}

		processedFiles = append(processedFiles, path)
	}

	if !noRemoveFiles {
		processedFiles = utils.StrSliceDeduplicate(processedFiles)

		for _, file := range processedFiles {
			err = os.Remove(file)
			if err != nil {
				return nil, nil, fmt.Errorf("unable to remove file: %s", err)
			}
		}
	}

	return processedFiles, failedFiles, nil
}