package vociferate_test

import (
	"os"
	"os/exec"
	"path/filepath"
	"strings"
	"testing"

	"git.hrafn.xyz/aether/vociferate/internal/vociferate"
	"github.com/stretchr/testify/require"
	"github.com/stretchr/testify/suite"
)

type PrepareSuite struct {
	suite.Suite
	rootDir string
}

func TestPrepareSuite(t *testing.T) {
	suite.Run(t, new(PrepareSuite))
}

func (s *PrepareSuite) SetupTest() {
	s.rootDir = s.T().TempDir()
	s.T().Setenv("GITHUB_SERVER_URL", "")
	s.T().Setenv("GITHUB_REPOSITORY", "")

	runGit(s.T(), s.rootDir, "init")
	runGit(s.T(), s.rootDir, "config", "user.name", "Vociferate Tests")
	runGit(s.T(), s.rootDir, "config", "user.email", "vociferate-tests@example.com")
	require.NoError(s.T(), os.WriteFile(filepath.Join(s.rootDir, ".gitkeep"), []byte("\n"), 0o644))
	runGit(s.T(), s.rootDir, "add", ".gitkeep")
	runGit(s.T(), s.rootDir, "commit", "-m", "chore: initial test commit")
	runGit(s.T(), s.rootDir, "remote", "add", "origin", "git@git.hrafn.xyz:aether/vociferate.git")

	require.NoError(s.T(), os.WriteFile(
		filepath.Join(s.rootDir, "release-version"),
		[]byte("1.1.6\n"),
		0o644,
	))

	require.NoError(s.T(), os.WriteFile(
		filepath.Join(s.rootDir, "CHANGELOG.md"),
		[]byte("# Changelog\n\n## [Unreleased]\n\n### Breaking\n\n### Added\n\n- New thing.\n\n### Fixed\n\n- Old thing.\n\n## [1.1.6] - 2017-12-20\n\n### Fixed\n\n- Historical note.\n"),
		0o644,
	))
}

func runGit(t *testing.T, rootDir string, args ...string) string {
	t.Helper()

	command := exec.Command("git", append([]string{"-C", rootDir}, args...)...)
	output, err := command.CombinedOutput()
	require.NoError(t, err, "git %s failed:\n%s", strings.Join(args, " "), string(output))

	return strings.TrimSpace(string(output))
}

func firstCommitShortHash(t *testing.T, rootDir string) string {
	t.Helper()

	return runGit(t, rootDir, "rev-list", "--max-parents=0", "--abbrev-commit", "HEAD")
}

func (s *PrepareSuite) TestPrepare_UpdatesVersionAndPromotesUnreleasedNotes() {
	err := vociferate.Prepare(s.rootDir, "v1.1.7", "2026-03-20", vociferate.Options{})

	require.NoError(s.T(), err)

	versionBytes, err := os.ReadFile(filepath.Join(s.rootDir, "release-version"))
	require.NoError(s.T(), err)
	require.Equal(s.T(), "1.1.7\n", string(versionBytes))

	changelogBytes, err := os.ReadFile(filepath.Join(s.rootDir, "CHANGELOG.md"))
	require.NoError(s.T(), err)
	firstCommit := firstCommitShortHash(s.T(), s.rootDir)
	require.Equal(s.T(), "# Changelog\n\n## [Unreleased]\n\n### Breaking\n\n### Added\n\n### Changed\n\n### Removed\n\n### Fixed\n\n## [1.1.7] - 2026-03-20\n\n### Breaking\n\n### Added\n\n- New thing.\n\n### Fixed\n\n- Old thing.\n\n## [1.1.6] - 2017-12-20\n\n### Fixed\n\n- Historical note.\n\n[Unreleased]: https://git.hrafn.xyz/aether/vociferate/compare/v1.1.7...main\n[1.1.7]: https://git.hrafn.xyz/aether/vociferate/compare/v1.1.6...v1.1.7\n[1.1.6]: https://git.hrafn.xyz/aether/vociferate/compare/"+firstCommit+"...v1.1.6\n", string(changelogBytes))
}

func (s *PrepareSuite) TestPrepare_ReturnsErrorWhenUnreleasedSectionMissing() {
	require.NoError(s.T(), os.WriteFile(
		filepath.Join(s.rootDir, "CHANGELOG.md"),
		[]byte("# Changelog\n\n## [1.1.6] - 2017-12-20\n"),
		0o644,
	))

	err := vociferate.Prepare(s.rootDir, "1.1.7", "2026-03-20", vociferate.Options{})

	require.ErrorContains(s.T(), err, "unreleased section")
}

func (s *PrepareSuite) TestPrepare_ReturnsErrorWhenUnreleasedSectionIsEmpty() {
	require.NoError(s.T(), os.WriteFile(
		filepath.Join(s.rootDir, "CHANGELOG.md"),
		[]byte("# Changelog\n\n## [Unreleased]\n\n## [1.1.6] - 2017-12-20\n"),
		0o644,
	))

	err := vociferate.Prepare(s.rootDir, "1.1.7", "2026-03-20", vociferate.Options{})

	require.ErrorContains(s.T(), err, "unreleased section is empty")
}

func (s *PrepareSuite) TestRecommendedTag_UsesMinorBumpWhenBreakingHeadingIsEmpty() {
	tag, err := vociferate.RecommendedTag(s.rootDir, vociferate.Options{})

	require.NoError(s.T(), err)
	require.Equal(s.T(), "v1.2.0", tag)
}

func (s *PrepareSuite) TestUnreleasedBody_ReturnsStructuredPendingReleaseNotes() {
	body, err := vociferate.UnreleasedBody(s.rootDir, vociferate.Options{})

	require.NoError(s.T(), err)
	require.Equal(s.T(), "### Breaking\n\n### Added\n\n- New thing.\n\n### Fixed\n\n- Old thing.\n", body)
}

func (s *PrepareSuite) TestUnreleasedBody_ReturnsErrorWhenUnreleasedSectionMissing() {
	require.NoError(s.T(), os.WriteFile(
		filepath.Join(s.rootDir, "CHANGELOG.md"),
		[]byte("# Changelog\n\n## [1.1.6] - 2017-12-20\n"),
		0o644,
	))

	_, err := vociferate.UnreleasedBody(s.rootDir, vociferate.Options{})

	require.ErrorContains(s.T(), err, "unreleased section")
}

func (s *PrepareSuite) TestReleaseNotes_ReturnsReleaseSectionForVersion() {
	notes, err := vociferate.ReleaseNotes(s.rootDir, "1.1.6", vociferate.Options{})

	require.NoError(s.T(), err)
	require.Equal(s.T(), "## [1.1.6] - 2017-12-20\n\n### Fixed\n\n- Historical note.\n", notes)
}

func (s *PrepareSuite) TestReleaseNotes_ReturnsErrorWhenVersionSectionMissing() {
	_, err := vociferate.ReleaseNotes(s.rootDir, "9.9.9", vociferate.Options{})

	require.ErrorContains(s.T(), err, "release notes section")
}

func (s *PrepareSuite) TestRecommendedTag_ReturnsErrorWhenUnreleasedHasOnlyTemplateHeadings() {
	require.NoError(s.T(), os.WriteFile(
		filepath.Join(s.rootDir, "CHANGELOG.md"),
		[]byte("# Changelog\n\n## [Unreleased]\n\n### Breaking\n\n### Added\n\n### Changed\n\n### Removed\n\n### Fixed\n\n## [1.1.6] - 2017-12-20\n"),
		0o644,
	))

	_, err := vociferate.RecommendedTag(s.rootDir, vociferate.Options{})

	require.ErrorContains(s.T(), err, "unreleased section is empty")
}

func (s *PrepareSuite) TestRecommendedTag_UsesPatchBumpForFixOnlyChanges() {
	require.NoError(s.T(), os.WriteFile(
		filepath.Join(s.rootDir, "CHANGELOG.md"),
		[]byte("# Changelog\n\n## [Unreleased]\n\n### Fixed\n\n- Patch note.\n\n## [1.1.6] - 2017-12-20\n"),
		0o644,
	))

	tag, err := vociferate.RecommendedTag(s.rootDir, vociferate.Options{})

	require.NoError(s.T(), err)
	require.Equal(s.T(), "v1.1.7", tag)
}

func (s *PrepareSuite) TestRecommendedTag_UsesMajorBumpWhenRemovedEntriesExist() {
	require.NoError(s.T(), os.WriteFile(
		filepath.Join(s.rootDir, "CHANGELOG.md"),
		[]byte("# Changelog\n\n## [Unreleased]\n\n### Removed\n\n- Breaking removal.\n\n## [1.1.6] - 2017-12-20\n"),
		0o644,
	))

	tag, err := vociferate.RecommendedTag(s.rootDir, vociferate.Options{})

	require.NoError(s.T(), err)
	require.Equal(s.T(), "v2.0.0", tag)
}

func (s *PrepareSuite) TestRecommendedTag_UsesMajorBumpWhenBreakingEntriesExist() {
	require.NoError(s.T(), os.WriteFile(
		filepath.Join(s.rootDir, "CHANGELOG.md"),
		[]byte("# Changelog\n\n## [Unreleased]\n\n### Breaking\n\n- Changed API contract.\n\n### Changed\n\n- Updated defaults.\n\n## [1.1.6] - 2017-12-20\n"),
		0o644,
	))

	tag, err := vociferate.RecommendedTag(s.rootDir, vociferate.Options{})

	require.NoError(s.T(), err)
	require.Equal(s.T(), "v2.0.0", tag)
}

func (s *PrepareSuite) TestPrepare_UsesCustomVersionFileAndPattern() {
	customVersionFile := filepath.Join("custom", "VERSION.txt")
	require.NoError(s.T(), os.MkdirAll(filepath.Join(s.rootDir, "custom"), 0o755))
	require.NoError(s.T(), os.WriteFile(
		filepath.Join(s.rootDir, customVersionFile),
		[]byte("VERSION=1.1.6\n"),
		0o644,
	))

	err := vociferate.Prepare(s.rootDir, "1.1.8", "2026-03-20", vociferate.Options{
		VersionFile:    customVersionFile,
		VersionPattern: `VERSION=([^\n]+)`,
	})

	require.NoError(s.T(), err)

	versionBytes, err := os.ReadFile(filepath.Join(s.rootDir, customVersionFile))
	require.NoError(s.T(), err)
	require.Equal(s.T(), "VERSION=1.1.8\n", string(versionBytes))
}

func (s *PrepareSuite) TestPrepare_AllowsUnchangedVersionValue() {
	require.NoError(s.T(), os.WriteFile(
		filepath.Join(s.rootDir, "release-version"),
		[]byte("1.1.6\n"),
		0o644,
	))

	err := vociferate.Prepare(s.rootDir, "1.1.6", "2026-03-20", vociferate.Options{})

	require.NoError(s.T(), err)

	versionBytes, readErr := os.ReadFile(filepath.Join(s.rootDir, "release-version"))
	require.NoError(s.T(), readErr)
	require.Equal(s.T(), "1.1.6\n", string(versionBytes))
}

func (s *PrepareSuite) TestRecommendedTag_UsesChangelogVersionWhenNoVersionFileConfigured() {
	// The default release-version file is present from SetupTest but should be ignored;
	// the current version must be read from the changelog, not the file.
	require.NoError(s.T(), os.WriteFile(
		filepath.Join(s.rootDir, "release-version"),
		[]byte("99.99.99\n"), // deliberately wrong value
		0o644,
	))
	require.NoError(s.T(), os.WriteFile(
		filepath.Join(s.rootDir, "CHANGELOG.md"),
		[]byte("# Changelog\n\n## [Unreleased]\n\n### Fixed\n\n- A fix.\n\n## [3.0.0] - 2026-01-01\n\n### Fixed\n\n- Historical.\n"),
		0o644,
	))

	tag, err := vociferate.RecommendedTag(s.rootDir, vociferate.Options{})

	require.NoError(s.T(), err)
	require.Equal(s.T(), "v3.0.1", tag)
}

func (s *PrepareSuite) TestRecommendedTag_DefaultsToV1WhenNoPriorReleasesInChangelog() {
	require.NoError(s.T(), os.Remove(filepath.Join(s.rootDir, "release-version")))
	require.NoError(s.T(), os.WriteFile(
		filepath.Join(s.rootDir, "CHANGELOG.md"),
		[]byte("# Changelog\n\n## [Unreleased]\n\n### Breaking\n\n### Added\n\n- First feature.\n"),
		0o644,
	))

	tag, err := vociferate.RecommendedTag(s.rootDir, vociferate.Options{})

	require.NoError(s.T(), err)
	require.Equal(s.T(), "v1.0.0", tag)
}

func (s *PrepareSuite) TestPrepare_CreatesVersionFileWhenNotPresent() {
	require.NoError(s.T(), os.Remove(filepath.Join(s.rootDir, "release-version")))

	err := vociferate.Prepare(s.rootDir, "2.0.0", "2026-03-20", vociferate.Options{})

	require.NoError(s.T(), err)

	versionBytes, readErr := os.ReadFile(filepath.Join(s.rootDir, "release-version"))
	require.NoError(s.T(), readErr)
	require.Equal(s.T(), "2.0.0\n", string(versionBytes))
}

func (s *PrepareSuite) TestRecommendedTag_UsesCustomVersionFileAndPattern() {
	customVersionFile := filepath.Join("custom", "VERSION.txt")
	require.NoError(s.T(), os.MkdirAll(filepath.Join(s.rootDir, "custom"), 0o755))
	require.NoError(s.T(), os.WriteFile(
		filepath.Join(s.rootDir, customVersionFile),
		[]byte("VERSION=2.3.4\n"),
		0o644,
	))
	require.NoError(s.T(), os.WriteFile(
		filepath.Join(s.rootDir, "CHANGELOG.md"),
		[]byte("# Changelog\n\n## [Unreleased]\n\n### Added\n\n- Feature.\n\n## [2.3.4] - 2026-03-10\n"),
		0o644,
	))

	tag, err := vociferate.RecommendedTag(s.rootDir, vociferate.Options{
		VersionFile:    customVersionFile,
		VersionPattern: `VERSION=([^\n]+)`,
	})

	require.NoError(s.T(), err)
	require.Equal(s.T(), "v2.4.0", tag)
}

func (s *PrepareSuite) TestPrepare_UsesGitHrafnXYZEnvironmentForChangelogLinks() {
	s.T().Setenv("GITHUB_SERVER_URL", "https://git.hrafn.xyz")
	s.T().Setenv("GITHUB_REPOSITORY", "aether/vociferate")

	err := vociferate.Prepare(s.rootDir, "1.1.7", "2026-03-20", vociferate.Options{})
	require.NoError(s.T(), err)

	changelogBytes, readErr := os.ReadFile(filepath.Join(s.rootDir, "CHANGELOG.md"))
	require.NoError(s.T(), readErr)
	changelog := string(changelogBytes)
	firstCommit := firstCommitShortHash(s.T(), s.rootDir)

	require.Contains(s.T(), changelog, "## [Unreleased]\n")
	require.Contains(s.T(), changelog, "### Changed\n")
	require.Contains(s.T(), changelog, "### Removed\n")
	require.Contains(s.T(), changelog, "## [1.1.7] - 2026-03-20")
	require.Contains(s.T(), changelog, "## [1.1.6] - 2017-12-20")
	require.Contains(s.T(), changelog, "[Unreleased]: https://git.hrafn.xyz/aether/vociferate/compare/v1.1.7...main")
	require.Contains(s.T(), changelog, "[1.1.7]: https://git.hrafn.xyz/aether/vociferate/compare/v1.1.6...v1.1.7")
	require.Contains(s.T(), changelog, "[1.1.6]: https://git.hrafn.xyz/aether/vociferate/compare/"+firstCommit+"...v1.1.6")
}

func (s *PrepareSuite) TestPrepare_UsesGitHubEnvironmentForChangelogLinks() {
	s.T().Setenv("GITHUB_SERVER_URL", "https://github.com")
	s.T().Setenv("GITHUB_REPOSITORY", "aether/vociferate")

	err := vociferate.Prepare(s.rootDir, "1.1.7", "2026-03-20", vociferate.Options{})
	require.NoError(s.T(), err)

	changelogBytes, readErr := os.ReadFile(filepath.Join(s.rootDir, "CHANGELOG.md"))
	require.NoError(s.T(), readErr)
	changelog := string(changelogBytes)
	firstCommit := firstCommitShortHash(s.T(), s.rootDir)

	require.Contains(s.T(), changelog, "## [Unreleased]\n")
	require.Contains(s.T(), changelog, "### Changed\n")
	require.Contains(s.T(), changelog, "### Removed\n")
	require.Contains(s.T(), changelog, "## [1.1.7] - 2026-03-20")
	require.Contains(s.T(), changelog, "## [1.1.6] - 2017-12-20")
	require.Contains(s.T(), changelog, "[Unreleased]: https://github.com/aether/vociferate/compare/v1.1.7...main")
	require.Contains(s.T(), changelog, "[1.1.7]: https://github.com/aether/vociferate/compare/v1.1.6...v1.1.7")
	require.Contains(s.T(), changelog, "[1.1.6]: https://github.com/aether/vociferate/compare/"+firstCommit+"...v1.1.6")
}