package releasekit_test

import (
	"context"
	"errors"
	"os"
	"os/exec"
	"path/filepath"
	"testing"

	releasekit "gitea.maximumdirect.net/eric/ReleaseKit"
)

func TestPrepareTaggedCheckoutFetchesExpectedCommitAndDetaches(t *testing.T) {
	repository := newTaggedDeliveryConsumer(t)
	tagCommit := publishPreparationTag(t, repository)
	advancePreparationCheckout(t, repository, "later local commit")

	if err := releasekit.PrepareTaggedCheckout(context.Background(), releasekit.TaggedCheckoutRequest{
		RepositoryDir:  repository,
		Version:        "v1.2.3",
		ExpectedCommit: tagCommit,
	}); err != nil {
		t.Fatal(err)
	}
	if head := buildGit(t, repository, "rev-parse", "HEAD"); head != tagCommit {
		t.Fatalf("prepared HEAD = %s, want %s", head, tagCommit)
	}
	if branch := buildGit(t, repository, "rev-parse", "--abbrev-ref", "HEAD"); branch != "HEAD" {
		t.Fatalf("prepared checkout branch = %q, want detached HEAD", branch)
	}
}

func TestPrepareTaggedCheckoutRejectsWrongCommitBeforeCheckout(t *testing.T) {
	repository := newTaggedDeliveryConsumer(t)
	tagCommit := publishPreparationTag(t, repository)
	currentCommit := advancePreparationCheckout(t, repository, "later local commit")
	remote := buildGit(t, repository, "remote", "get-url", "origin")
	buildGit(t, repository, "remote", "add", "candidate", remote)

	err := releasekit.PrepareTaggedCheckout(context.Background(), releasekit.TaggedCheckoutRequest{
		RepositoryDir:  repository,
		Version:        "v1.2.3",
		Remote:         "candidate",
		ExpectedCommit: currentCommit,
	})
	if err == nil {
		t.Fatal("PrepareTaggedCheckout() succeeded for a tag that resolves to another commit")
	}
	if head := buildGit(t, repository, "rev-parse", "HEAD"); head != currentCommit {
		t.Fatalf("wrong-tag rejection changed HEAD to %s, want %s (tag commit %s)", head, currentCommit, tagCommit)
	}
	if branch := buildGit(t, repository, "rev-parse", "--abbrev-ref", "HEAD"); branch == "HEAD" {
		t.Fatal("wrong-tag rejection detached the checkout")
	}
}

func TestPrepareTaggedCheckoutReportsLocalCheckoutConflict(t *testing.T) {
	repository := newTaggedDeliveryConsumer(t)
	tagCommit := publishPreparationTag(t, repository)
	advancePreparationCheckout(t, repository, "later committed content")
	path := filepath.Join(repository, "cmd/app/main.go")
	if err := os.WriteFile(path, []byte("uncommitted conflicting content"), 0o600); err != nil {
		t.Fatal(err)
	}
	currentCommit := buildGit(t, repository, "rev-parse", "HEAD")

	err := releasekit.PrepareTaggedCheckout(context.Background(), releasekit.TaggedCheckoutRequest{
		RepositoryDir:  repository,
		Version:        "v1.2.3",
		ExpectedCommit: tagCommit,
	})
	if err == nil {
		t.Fatal("PrepareTaggedCheckout() succeeded despite a conflicting local edit")
	}
	if head := buildGit(t, repository, "rev-parse", "HEAD"); head != currentCommit {
		t.Fatalf("conflicting checkout changed HEAD to %s, want %s", head, currentCommit)
	}
	contents, err := os.ReadFile(path)
	if err != nil || string(contents) != "uncommitted conflicting content" {
		t.Fatalf("conflicting local file = %q, %v", contents, err)
	}
}

func TestPrepareTaggedCheckoutReportsConflictingLocalTag(t *testing.T) {
	repository := newTaggedDeliveryConsumer(t)
	publishPreparationTag(t, repository)
	currentCommit := advancePreparationCheckout(t, repository, "later local commit")
	buildGit(t, repository, "tag", "v1.2.3")

	err := releasekit.PrepareTaggedCheckout(context.Background(), releasekit.TaggedCheckoutRequest{
		RepositoryDir:  repository,
		Version:        "v1.2.3",
		ExpectedCommit: buildGit(t, repository, "rev-parse", "HEAD~1"),
	})
	if err == nil {
		t.Fatal("PrepareTaggedCheckout() replaced a conflicting local tag")
	}
	if head := buildGit(t, repository, "rev-parse", "HEAD"); head != currentCommit {
		t.Fatalf("conflicting tag fetch changed HEAD to %s, want %s", head, currentCommit)
	}
	if tagCommit := buildGit(t, repository, "rev-parse", "refs/tags/v1.2.3^{commit}"); tagCommit != currentCommit {
		t.Fatalf("conflicting local tag changed to %s, want %s", tagCommit, currentCommit)
	}
}

func TestPrepareTaggedCheckoutValidatesInputsBeforeFetching(t *testing.T) {
	repository := newTaggedDeliveryConsumer(t)
	publishPreparationTag(t, repository)
	for _, request := range []releasekit.TaggedCheckoutRequest{
		{RepositoryDir: repository, Version: "not-a-version", ExpectedCommit: buildGit(t, repository, "rev-parse", "HEAD")},
		{RepositoryDir: repository, Version: "v1.2.3"},
		{RepositoryDir: repository, Version: "v1.2.3", ExpectedCommit: "not-an-object-id"},
	} {
		err := releasekit.PrepareTaggedCheckout(context.Background(), request)
		if err == nil {
			t.Fatalf("PrepareTaggedCheckout(%#v) succeeded", request)
		}
		if _, err := buildGitOutput(repository, "show-ref", "--verify", "refs/tags/v1.2.3"); err == nil {
			t.Fatal("input validation fetched the tag before rejecting the request")
		}
	}
	if err := releasekit.PrepareTaggedCheckout(context.Background(), releasekit.TaggedCheckoutRequest{
		RepositoryDir: repository, Version: "invalid", ExpectedCommit: "bad",
	}); !errors.Is(err, releasekit.ErrInvalidVersion) {
		t.Fatalf("invalid-version error = %v, want ErrInvalidVersion", err)
	}
}

func TestPrepareBuildDependenciesRequiresRepositoryDirectory(t *testing.T) {
	if err := releasekit.PrepareBuildDependencies(context.Background(), " "); err == nil {
		t.Fatal("PrepareBuildDependencies() accepted an empty repository directory")
	}
}

func publishPreparationTag(t *testing.T, repository string) string {
	t.Helper()
	remoteDir := t.TempDir()
	remote := filepath.Join(remoteDir, "origin.git")
	buildGit(t, remoteDir, "init", "--bare", remote)
	buildGit(t, repository, "remote", "add", "origin", remote)
	commit := buildGit(t, repository, "rev-parse", "refs/tags/v1.2.3^{commit}")
	buildGit(t, repository, "push", "origin", "refs/tags/v1.2.3")
	buildGit(t, repository, "tag", "-d", "v1.2.3")
	return commit
}

func advancePreparationCheckout(t *testing.T, repository, source string) string {
	t.Helper()
	path := filepath.Join(repository, "cmd/app/main.go")
	if err := os.WriteFile(path, []byte("package main\n// "+source+"\nfunc main() {}\n"), 0o600); err != nil {
		t.Fatal(err)
	}
	buildGit(t, repository, "add", "cmd/app/main.go")
	buildGit(t, repository, "commit", "-m", source)
	return buildGit(t, repository, "rev-parse", "HEAD")
}

func buildGitOutput(repository string, args ...string) ([]byte, error) {
	command := exec.Command("git", args...)
	command.Dir = repository
	return command.Output()
}