package main_test

import (
	"fmt"
	"io"
	"io/ioutil"
	"os"
	"os/exec"
	"path/filepath"
	"testing"
	"time"

	"github.com/github/git-sizer/counts"
	"github.com/github/git-sizer/git"
	"github.com/github/git-sizer/sizes"

	"github.com/stretchr/testify/assert"
	"github.com/stretchr/testify/require"
)

// Smoke test that the program runs.
func TestExec(t *testing.T) {
	cmd := exec.Command("bin/git-sizer")
	output, err := cmd.CombinedOutput()
	assert.NoErrorf(t, err, "command failed; output: %#v", string(output))
}

func gitCommand(t *testing.T, repo *git.Repository, args ...string) *exec.Cmd {
	cmd := exec.Command("git", args...)
	cmd.Env = append(os.Environ(), "GIT_DIR="+repo.Path())
	return cmd
}

func addFile(t *testing.T, repoPath string, repo *git.Repository, relativePath, contents string) {
	dirPath := filepath.Dir(relativePath)
	if dirPath != "." {
		require.NoError(t, os.MkdirAll(filepath.Join(repoPath, dirPath), 0777), "creating subdir")
	}

	filename := filepath.Join(repoPath, relativePath)
	f, err := os.Create(filename)
	require.NoErrorf(t, err, "creating file %q", filename)
	_, err = f.WriteString(contents)
	require.NoErrorf(t, err, "writing to file %q", filename)
	require.NoErrorf(t, f.Close(), "closing file %q", filename)

	cmd := gitCommand(t, repo, "add", relativePath)
	cmd.Dir = repoPath
	require.NoErrorf(t, cmd.Run(), "adding file %q", relativePath)
}

func addAuthorInfo(cmd *exec.Cmd, timestamp *time.Time) {
	cmd.Env = append(cmd.Env,
		"GIT_AUTHOR_NAME=Arthur",
		"GIT_AUTHOR_EMAIL=arthur@example.com",
		fmt.Sprintf("GIT_AUTHOR_DATE=%d -0700", timestamp.Unix()),
		"GIT_COMMITTER_NAME=Constance",
		"GIT_COMMITTER_EMAIL=constance@example.com",
		fmt.Sprintf("GIT_COMMITTER_DATE=%d -0700", timestamp.Unix()),
	)
	*timestamp = timestamp.Add(60 * time.Second)
}

func newGitBomb(
	repoName string, depth, breadth int, body string,
) (repo *git.Repository, err error) {
	path, err := ioutil.TempDir("", repoName)
	if err != nil {
		return nil, err
	}

	defer func() {
		if err != nil {
			os.RemoveAll(path)
		}
	}()

	cmd := exec.Command("git", "init", "--bare", path)
	err = cmd.Run()
	if err != nil {
		return nil, err
	}

	repo, err = git.NewRepository(path)
	if err != nil {
		return nil, err
	}

	oid, err := repo.CreateObject("blob", func(w io.Writer) error {
		_, err := io.WriteString(w, body)
		return err
	})

	digits := len(fmt.Sprintf("%d", breadth-1))

	mode := "100644"
	prefix := "f"

	for ; depth > 0; depth-- {
		oid, err = repo.CreateObject("tree", func(w io.Writer) error {
			for i := 0; i < breadth; i++ {
				_, err = fmt.Fprintf(
					w, "%s %s%0*d\x00%s",
					mode, prefix, digits, i, oid.Bytes(),
				)
				if err != nil {
					return err
				}
			}
			return nil
		})
		if err != nil {
			return nil, err
		}

		mode = "40000"
		prefix = "d"
	}

	oid, err = repo.CreateObject("commit", func(w io.Writer) error {
		_, err := fmt.Fprintf(
			w,
			"tree %s\n"+
				"author Example <example@example.com> 1112911993 -0700\n"+
				"committer Example <example@example.com> 1112911993 -0700\n"+
				"\n"+
				"Mwahahaha!\n",
			oid,
		)
		return err
	})
	if err != nil {
		return nil, err
	}

	err = repo.UpdateRef("refs/heads/master", oid)
	if err != nil {
		return nil, err
	}

	return repo, nil
}

func pow(x uint64, n int) uint64 {
	p := uint64(1)
	for ; n > 0; n-- {
		p *= x
	}
	return p
}

func TestBomb(t *testing.T) {
	t.Parallel()
	assert := assert.New(t)

	repo, err := newGitBomb("bomb", 10, 10, "boom!\n")
	if err != nil {
		t.Errorf("failed to create bomb: %s", err)
	}
	defer os.RemoveAll(repo.Path())

	h, err := sizes.ScanRepositoryUsingGraph(
		repo, git.AllReferencesFilter, sizes.NameStyleFull, false,
	)
	if !assert.NoError(err) {
		return
	}

	assert.Equal(counts.Count32(1), h.UniqueCommitCount, "unique commit count")
	assert.Equal(counts.Count64(169), h.UniqueCommitSize, "unique commit size")
	assert.Equal(counts.Count32(169), h.MaxCommitSize, "max commit size")
	assert.Equal("refs/heads/master", h.MaxCommitSizeCommit.Path(), "max commit size commit")
	assert.Equal(counts.Count32(1), h.MaxHistoryDepth, "max history depth")
	assert.Equal(counts.Count32(0), h.MaxParentCount, "max parent count")
	assert.Equal("refs/heads/master", h.MaxParentCountCommit.Path(), "max parent count commit")

	assert.Equal(counts.Count32(10), h.UniqueTreeCount, "unique tree count")
	assert.Equal(counts.Count64(2910), h.UniqueTreeSize, "unique tree size")
	assert.Equal(counts.Count64(100), h.UniqueTreeEntries, "unique tree entries")
	assert.Equal(counts.Count32(10), h.MaxTreeEntries, "max tree entries")
	assert.Equal("refs/heads/master:d0/d0/d0/d0/d0/d0/d0/d0/d0", h.MaxTreeEntriesTree.Path(), "max tree entries tree")

	assert.Equal(counts.Count32(1), h.UniqueBlobCount, "unique blob count")
	assert.Equal(counts.Count64(6), h.UniqueBlobSize, "unique blob size")
	assert.Equal(counts.Count32(6), h.MaxBlobSize, "max blob size")
	assert.Equal("refs/heads/master:d0/d0/d0/d0/d0/d0/d0/d0/d0/f0", h.MaxBlobSizeBlob.Path(), "max blob size blob")

	assert.Equal(counts.Count32(0), h.UniqueTagCount, "unique tag count")
	assert.Equal(counts.Count32(0), h.MaxTagDepth, "max tag depth")

	assert.Equal(counts.Count32(1), h.ReferenceCount, "reference count")

	assert.Equal(counts.Count32(10), h.MaxPathDepth, "max path depth")
	assert.Equal("refs/heads/master^{tree}", h.MaxPathDepthTree.Path(), "max path depth tree")
	assert.Equal(counts.Count32(29), h.MaxPathLength, "max path length")
	assert.Equal("refs/heads/master^{tree}", h.MaxPathLengthTree.Path(), "max path length tree")

	assert.Equal(counts.Count32((pow(10, 10)-1)/(10-1)), h.MaxExpandedTreeCount, "max expanded tree count")
	assert.Equal("refs/heads/master^{tree}", h.MaxExpandedTreeCountTree.Path(), "max expanded tree count tree")
	assert.Equal(counts.Count32(0xffffffff), h.MaxExpandedBlobCount, "max expanded blob count")
	assert.Equal("refs/heads/master^{tree}", h.MaxExpandedBlobCountTree.Path(), "max expanded blob count tree")
	assert.Equal(counts.Count64(6*pow(10, 10)), h.MaxExpandedBlobSize, "max expanded blob size")
	assert.Equal("refs/heads/master^{tree}", h.MaxExpandedBlobSizeTree.Path(), "max expanded blob size tree")
	assert.Equal(counts.Count32(0), h.MaxExpandedLinkCount, "max expanded link count")
	assert.Nil(h.MaxExpandedLinkCountTree, "max expanded link count tree")
	assert.Equal(counts.Count32(0), h.MaxExpandedSubmoduleCount, "max expanded submodule count")
	assert.Nil(h.MaxExpandedSubmoduleCountTree, "max expanded submodule count tree")
}

func TestTaggedTags(t *testing.T) {
	t.Parallel()
	path, err := ioutil.TempDir("", "tagged-tags")
	require.NoError(t, err, "creating temporary directory")

	defer func() {
		os.RemoveAll(path)
	}()

	cmd := exec.Command("git", "init", path)
	require.NoError(t, cmd.Run(), "initializing repo")
	repo, err := git.NewRepository(path)
	require.NoError(t, err, "initializing Repository object")

	timestamp := time.Unix(1112911993, 0)

	cmd = gitCommand(t, repo, "commit", "-m", "initial", "--allow-empty")
	addAuthorInfo(cmd, &timestamp)
	require.NoError(t, cmd.Run(), "creating commit")

	// The lexicographical order of these tags is important, hence
	// their strange names.
	cmd = gitCommand(t, repo, "tag", "-m", "tag 1", "tag", "master")
	addAuthorInfo(cmd, &timestamp)
	require.NoError(t, cmd.Run(), "creating tag 1")

	cmd = gitCommand(t, repo, "tag", "-m", "tag 2", "bag", "tag")
	addAuthorInfo(cmd, &timestamp)
	require.NoError(t, cmd.Run(), "creating tag 2")

	cmd = gitCommand(t, repo, "tag", "-m", "tag 3", "wag", "bag")
	addAuthorInfo(cmd, &timestamp)
	require.NoError(t, cmd.Run(), "creating tag 3")

	h, err := sizes.ScanRepositoryUsingGraph(
		repo, git.AllReferencesFilter, sizes.NameStyleNone, false,
	)
	require.NoError(t, err, "scanning repository")
	assert.Equal(t, counts.Count32(3), h.MaxTagDepth, "tag depth")
}

func TestFromSubdir(t *testing.T) {
	t.Parallel()
	path, err := ioutil.TempDir("", "subdir")
	require.NoError(t, err, "creating temporary directory")

	defer func() {
		os.RemoveAll(path)
	}()

	cmd := exec.Command("git", "init", path)
	require.NoError(t, cmd.Run(), "initializing repo")
	repo, err := git.NewRepository(path)
	require.NoError(t, err, "initializing Repository object")

	timestamp := time.Unix(1112911993, 0)

	addFile(t, path, repo, "subdir/file.txt", "Hello, world!\n")

	cmd = gitCommand(t, repo, "commit", "-m", "initial")
	addAuthorInfo(cmd, &timestamp)
	require.NoError(t, cmd.Run(), "creating commit")

	repo2, err := git.NewRepository(filepath.Join(path, "subdir"))
	require.NoError(t, err, "creating Repository object in subdirectory")
	h, err := sizes.ScanRepositoryUsingGraph(
		repo2, git.AllReferencesFilter, sizes.NameStyleNone, false,
	)
	require.NoError(t, err, "scanning repository")
	assert.Equal(t, counts.Count32(2), h.MaxPathDepth, "max path depth")
}

func TestSubmodule(t *testing.T) {
	t.Parallel()
	path, err := ioutil.TempDir("", "submodule")
	require.NoError(t, err, "creating temporary directory")

	defer func() {
		os.RemoveAll(path)
	}()

	timestamp := time.Unix(1112911993, 0)

	submPath := filepath.Join(path, "subm")
	cmd := exec.Command("git", "init", submPath)
	require.NoError(t, cmd.Run(), "initializing subm repo")
	submRepo, err := git.NewRepository(submPath)
	require.NoError(t, err, "initializing subm Repository object")
	addFile(t, submPath, submRepo, "submfile1.txt", "Hello, submodule!\n")
	addFile(t, submPath, submRepo, "submfile2.txt", "Hello again, submodule!\n")
	addFile(t, submPath, submRepo, "submfile3.txt", "Hello again, submodule!\n")

	cmd = gitCommand(t, submRepo, "commit", "-m", "subm initial")
	addAuthorInfo(cmd, &timestamp)
	require.NoError(t, cmd.Run(), "creating subm commit")

	mainPath := filepath.Join(path, "main")
	cmd = exec.Command("git", "init", mainPath)
	require.NoError(t, cmd.Run(), "initializing main repo")
	mainRepo, err := git.NewRepository(mainPath)
	require.NoError(t, err, "initializing main Repository object")
	addFile(t, mainPath, mainRepo, "mainfile.txt", "Hello, main!\n")

	cmd = gitCommand(t, mainRepo, "commit", "-m", "main initial")
	addAuthorInfo(cmd, &timestamp)
	require.NoError(t, cmd.Run(), "creating main commit")

	// Make subm a submodule of main:
	cmd = gitCommand(t, mainRepo, "submodule", "add", submPath, "sub")
	cmd.Dir = mainPath
	require.NoError(t, cmd.Run(), "adding submodule")

	cmd = gitCommand(t, mainRepo, "commit", "-m", "add submodule")
	addAuthorInfo(cmd, &timestamp)
	require.NoError(t, cmd.Run(), "committing submodule to main")

	// Analyze the main repo:
	h, err := sizes.ScanRepositoryUsingGraph(
		mainRepo, git.AllReferencesFilter, sizes.NameStyleNone, false,
	)
	require.NoError(t, err, "scanning repository")
	assert.Equal(t, counts.Count32(2), h.UniqueBlobCount, "unique blob count")
	assert.Equal(t, counts.Count32(2), h.MaxExpandedBlobCount, "max expanded blob count")
	assert.Equal(t, counts.Count32(1), h.MaxExpandedSubmoduleCount, "max expanded submodule count")

	// Analyze the submodule:
	submRepo2, err := git.NewRepository(filepath.Join(mainPath, "sub"))
	require.NoError(t, err, "creating Repository object in submodule")
	h, err = sizes.ScanRepositoryUsingGraph(
		submRepo2, git.AllReferencesFilter, sizes.NameStyleNone, false,
	)
	require.NoError(t, err, "scanning repository")
	assert.Equal(t, counts.Count32(2), h.UniqueBlobCount, "unique blob count")
	assert.Equal(t, counts.Count32(3), h.MaxExpandedBlobCount, "max expanded blob count")
}