package scripts_test

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

type changelogGateRepo struct {
	root string
	gate string
	base string
}

const changelogGateBase = `# Changelog

## [Unreleased]

## [1.0.0] - 2026-07-01

### Added

- Initial release.
`

const changelogGateValidRelease = `# Changelog

## [Unreleased]

## [1.0.1-beta.1] - 2026-07-17

### Changed

- Valid release note.

## [1.0.0] - 2026-07-01

### Added

- Initial release.
`

func newChangelogGateRepo(t *testing.T) *changelogGateRepo {
	t.Helper()

	sourceRoot, err := filepath.Abs(filepath.Join("..", ".."))
	if err != nil {
		t.Fatalf("Abs(repo root) error = %v", err)
	}
	root := t.TempDir()

	for _, path := range []string{
		"LICENSE",
		"NOTICE",
		"README.md",
		"CONTRIBUTING.md",
		"SECURITY.md",
		"CODE_OF_CONDUCT.md",
		".env.example",
		".github/workflows/ci.yml",
		".github/PULL_REQUEST_TEMPLATE.md",
		"docs/architecture.md",
		"scripts/README.md",
		"build/README.md",
	} {
		changelogGateWrite(t, root, path, "fixture\n", 0o644)
	}
	for _, path := range []string{
		"scripts/policy/check-changelog-pr.sh",
		"scripts/policy/open-source-audit.sh",
		"scripts/release/release-lib.sh",
	} {
		data, err := os.ReadFile(filepath.Join(sourceRoot, path))
		if err != nil {
			t.Fatalf("ReadFile(%s) error = %v", path, err)
		}
		mode := os.FileMode(0o644)
		if strings.HasSuffix(path, ".sh") {
			mode = 0o755
		}
		changelogGateWrite(t, root, path, string(data), mode)
	}
	changelogGateWrite(t, root, "CHANGELOG.md", changelogGateBase, 0o644)

	changelogGateGit(t, root, "init", "-b", "main")
	changelogGateGit(t, root, "config", "user.name", "Changelog Gate Test")
	changelogGateGit(t, root, "config", "user.email", "changelog-gate@example.com")
	changelogGateGit(t, root, "add", ".")
	changelogGateGit(t, root, "commit", "-m", "seed repository")

	return &changelogGateRepo{
		root: root,
		gate: filepath.Join(root, "scripts", "policy", "check-changelog-pr.sh"),
		base: strings.TrimSpace(changelogGateGit(t, root, "rev-parse", "HEAD")),
	}
}

func changelogGateWrite(t *testing.T, root, path, content string, mode os.FileMode) {
	t.Helper()
	full := filepath.Join(root, path)
	if err := os.MkdirAll(filepath.Dir(full), 0o755); err != nil {
		t.Fatalf("MkdirAll(%s) error = %v", filepath.Dir(full), err)
	}
	if err := os.WriteFile(full, []byte(content), mode); err != nil {
		t.Fatalf("WriteFile(%s) error = %v", full, err)
	}
}

func changelogGateGit(t *testing.T, root string, args ...string) string {
	t.Helper()
	cmd := exec.Command("git", args...)
	cmd.Dir = root
	output, err := cmd.CombinedOutput()
	if err != nil {
		t.Fatalf("git %s error = %v\noutput:\n%s", strings.Join(args, " "), err, output)
	}
	return string(output)
}

func (r *changelogGateRepo) commit(t *testing.T, message string) {
	t.Helper()
	changelogGateGit(t, r.root, "add", "-A")
	changelogGateGit(t, r.root, "commit", "-m", message)
}

func (r *changelogGateRepo) run(t *testing.T) (string, error) {
	t.Helper()
	return r.runMode(t, "--fast-path")
}

func (r *changelogGateRepo) runMode(t *testing.T, mode string) (string, error) {
	t.Helper()
	return r.runRefs(t, mode, r.base, "HEAD")
}

func (r *changelogGateRepo) runRefs(t *testing.T, mode, base, head string) (string, error) {
	t.Helper()
	cmd := exec.Command("sh", r.gate, mode, base, head)
	cmd.Dir = r.root
	output, err := cmd.CombinedOutput()
	return string(output), err
}

func TestChangelogPRGateAcceptsTargetedChanges(t *testing.T) {
	tests := []struct {
		name      string
		changelog string
	}{
		{
			name: "new release section with lowercase todo product",
			changelog: `# Changelog

## [Unreleased]

## [1.0.1-beta.1] - 2026-07-17

### Changed

- Improve the lowercase todo command family without leaving a placeholder.

## [1.0.0] - 2026-07-01

### Added

- Initial release.
`,
		},
		{
			name: "unreleased note",
			changelog: `# Changelog

## [Unreleased]

### Changed

- Document the next release candidate.

## [1.0.0] - 2026-07-01

### Added

- Initial release.
`,
		},
	}

	for _, test := range tests {
		t.Run(test.name, func(t *testing.T) {
			repo := newChangelogGateRepo(t)
			changelogGateWrite(t, repo.root, "CHANGELOG.md", test.changelog, 0o644)
			repo.commit(t, test.name)

			output, err := repo.run(t)
			if err != nil {
				t.Fatalf("gate error = %v\noutput:\n%s", err, output)
			}
			if !strings.Contains(output, "CHANGELOG PR check: ok") {
				t.Fatalf("gate output missing success marker:\n%s", output)
			}
		})
	}
}

func TestChangelogPRContentOnlyAllowsOtherFiles(t *testing.T) {
	repo := newChangelogGateRepo(t)
	changelogGateWrite(t, repo.root, "CHANGELOG.md", changelogGateValidRelease, 0o644)
	changelogGateWrite(t, repo.root, "internal/change.go", "package internal\n", 0o644)
	repo.commit(t, "change code with release notes")

	output, err := repo.runMode(t, "--content-only")
	if err != nil {
		t.Fatalf("content-only gate error = %v\noutput:\n%s", err, output)
	}
	if !strings.Contains(output, "CHANGELOG PR check: ok (mode=content-only") {
		t.Fatalf("content-only gate output missing success marker:\n%s", output)
	}
}

func TestChangelogPRContentOnlyStillValidatesContentWithOtherFiles(t *testing.T) {
	tests := []struct {
		name       string
		changelog  string
		wantOutput string
	}{
		{
			name: "invalid calendar date",
			changelog: strings.Replace(
				changelogGateValidRelease,
				"2026-07-17",
				"2026-02-30",
				1,
			),
			wantOutput: "invalid calendar date",
		},
		{
			name: "placeholder",
			changelog: strings.Replace(
				changelogGateValidRelease,
				"- Valid release note.",
				"- TODO: write release notes.",
				1,
			),
			wantOutput: "must not contain TODO/TBD",
		},
	}

	for _, test := range tests {
		t.Run(test.name, func(t *testing.T) {
			repo := newChangelogGateRepo(t)
			changelogGateWrite(t, repo.root, "CHANGELOG.md", test.changelog, 0o644)
			changelogGateWrite(t, repo.root, "internal/change.go", "package internal\n", 0o644)
			repo.commit(t, test.name)

			output, err := repo.runMode(t, "--content-only")
			if err == nil {
				t.Fatalf("unsafe content-only change unexpectedly passed:\n%s", output)
			}
			if !strings.Contains(output, test.wantOutput) {
				t.Fatalf("content-only gate output missing %q:\n%s", test.wantOutput, output)
			}
		})
	}
}

func TestChangelogPRGateValidatesSyntheticMergeTree(t *testing.T) {
	repo := newChangelogGateRepo(t)
	commonChangelog := `# Changelog

## [Unreleased]

## [1.0.0] - 2026-07-01

### Added

- Initial release.

## [0.9.0] - 2026-06-01

### Added

- Earlier release.
`
	changelogGateWrite(t, repo.root, "CHANGELOG.md", commonChangelog, 0o644)
	repo.commit(t, "expand changelog history")
	common := strings.TrimSpace(changelogGateGit(t, repo.root, "rev-parse", "HEAD"))
	repo.base = common

	changelogGateGit(t, repo.root, "switch", "-c", "feature")
	featureChangelog := strings.Replace(
		commonChangelog,
		"## [1.0.0] - 2026-07-01",
		`## [1.0.1-beta.1] - 2026-07-17

### Changed

- Feature branch release note.

## [1.0.0] - 2026-07-01`,
		1,
	)
	changelogGateWrite(t, repo.root, "CHANGELOG.md", featureChangelog, 0o644)
	repo.commit(t, "add feature release note")
	featureHead := strings.TrimSpace(changelogGateGit(t, repo.root, "rev-parse", "HEAD"))
	if output, err := repo.runRefs(t, "--fast-path", common, featureHead); err != nil {
		t.Fatalf("feature head should be valid before merging: %v\n%s", err, output)
	}

	changelogGateGit(t, repo.root, "switch", "main")
	mainChangelog := strings.Replace(
		commonChangelog,
		"## [0.9.0] - 2026-06-01",
		`## [1.0.1-beta.1] - 2026-07-17

### Changed

- Main branch release note.

## [0.9.0] - 2026-06-01`,
		1,
	)
	changelogGateWrite(t, repo.root, "CHANGELOG.md", mainChangelog, 0o644)
	repo.commit(t, "add main release note")
	mergeBase := strings.TrimSpace(changelogGateGit(t, repo.root, "rev-parse", "HEAD"))
	changelogGateGit(t, repo.root, "merge", "--no-ff", "feature", "-m", "merge feature")
	mergeHead := strings.TrimSpace(changelogGateGit(t, repo.root, "rev-parse", "HEAD"))

	output, err := repo.runRefs(t, "--fast-path", mergeBase, mergeHead)
	if err == nil {
		t.Fatalf("synthetic merge with duplicate release heading unexpectedly passed:\n%s", output)
	}
	if !strings.Contains(output, "exactly one well-formed section") {
		t.Fatalf("synthetic merge rejection missing duplicate-section evidence:\n%s", output)
	}
}

func TestChangelogPRGateRejectsExecutableModeInBothModes(t *testing.T) {
	for _, mode := range []string{"--fast-path", "--content-only"} {
		t.Run(strings.TrimPrefix(mode, "--"), func(t *testing.T) {
			repo := newChangelogGateRepo(t)
			changelogGateWrite(t, repo.root, "CHANGELOG.md", changelogGateValidRelease, 0o644)
			changelogGateGit(t, repo.root, "add", "CHANGELOG.md")
			changelogGateGit(t, repo.root, "update-index", "--chmod=+x", "CHANGELOG.md")
			changelogGateGit(t, repo.root, "commit", "-m", "make changelog executable")

			output, err := repo.runMode(t, mode)
			if err == nil {
				t.Fatalf("executable CHANGELOG unexpectedly passed:\n%s", output)
			}
			if !strings.Contains(output, "regular 100644 blob at head") {
				t.Fatalf("gate output missing regular-file rejection:\n%s", output)
			}
		})
	}
}

func TestReleaseChangelogExtractionAllowsLowercaseTodoProductName(t *testing.T) {
	sourceRoot, err := filepath.Abs(filepath.Join("..", ".."))
	if err != nil {
		t.Fatalf("Abs(repo root) error = %v", err)
	}
	changelog := filepath.Join(t.TempDir(), "CHANGELOG.md")
	changelogGateWrite(t, filepath.Dir(changelog), filepath.Base(changelog), `# Changelog

## [1.0.1-beta.1] - 2026-07-17

### Changed

- Improve the lowercase todo command family.
`, 0o644)

	cmd := exec.Command(
		"sh",
		"-c",
		`. "$1"; release_extract_changelog "$2" 1.0.1-beta.1 -`,
		"sh",
		filepath.Join(sourceRoot, "scripts", "release", "release-lib.sh"),
		changelog,
	)
	output, err := cmd.CombinedOutput()
	if err != nil {
		t.Fatalf("release_extract_changelog error = %v\noutput:\n%s", err, output)
	}
}

func TestChangelogPRFastPathWorkflowContract(t *testing.T) {
	root, err := filepath.Abs(filepath.Join("..", ".."))
	if err != nil {
		t.Fatalf("Abs(repo root) error = %v", err)
	}

	readWorkflow := func(path string) string {
		t.Helper()
		data, readErr := os.ReadFile(filepath.Join(root, path))
		if readErr != nil {
			t.Fatalf("ReadFile(%s) error = %v", path, readErr)
		}
		return string(data)
	}

	admission := readWorkflow(".github/workflows/ci.yml")
	for _, want := range []string{
		"name: CI",
		"files.length === 1",
		"files[0].filename === 'CHANGELOG.md'",
		"files[0].status === 'modified'",
		"!files[0].previous_filename",
		"pre-classification",
		"post-classification",
		"before.changed_files !== files.length",
		"after.changed_files !== files.length",
		`test "$(git rev-parse HEAD^1)" = "$PR_BASE_SHA"`,
		`test "$(git rev-parse HEAD^2)" = "$PR_HEAD_SHA"`,
		"Files API and synthetic merge tree disagree on CHANGELOG scope",
		"mode=--content-only",
		"mode=--fast-path",
		`"$mode" "$PR_BASE_SHA" HEAD`,
		"needs.lint.outputs.platform_sensitive == 'true'",
		`COVERAGE_TARGET: "100"`,
		`COVERAGE_ENFORCE_OVERALL: "false"`,
		`COVERAGE_OVERALL_TOLERANCE: "0"`,
		`COVERAGE_ADDITIONAL_DIFF_PROFILE=coverage-shortcut.txt`,
		"run: make test-plan",
		"run: make format-check",
		"./scripts/ci/test-packages.sh list",
		`package_output="$(./scripts/ci/test-packages.sh list`,
	} {
		if !strings.Contains(admission, want) {
			t.Errorf("Code Admission workflow missing contract %q", want)
		}
	}
	for _, context := range []string{
		"Lint",
		"Test",
		"Coverage",
		"Policy",
		"Edition",
		"Interface Integrity",
		"CLI Smoke",
		"Mock MCP",
	} {
		if !strings.Contains(admission, "\n    name: "+context+"\n") {
			t.Errorf("Code Admission workflow missing exact context %q", context)
		}
	}
	for _, forbidden := range []string{
		"name: CI Gate",
		"name: Changelog Check",
		"name: Policy Check",
		"name: Edition Contract Tests",
		"name: Mock MCP Smoke",
	} {
		if strings.Contains(admission, forbidden) {
			t.Errorf("Code Admission workflow retains legacy context %q", forbidden)
		}
	}
	if strings.Contains(admission, "paths-ignore:") {
		t.Error("Code Admission must not suppress required contexts with paths-ignore")
	}

	notification := readWorkflow(".github/workflows/notify-wukong.yml")
	if !strings.Contains(notification, "- CI") {
		t.Error("Wukong notification must follow the renamed CI workflow")
	}
	if strings.Contains(notification, "Code Admission — PR 合入门禁") {
		t.Error("Wukong notification still follows the retired workflow display name")
	}

	coverageGate := readWorkflow("scripts/policy/check-coverage-gate.sh")
	if !strings.Contains(coverageGate, `TARGET="${COVERAGE_TARGET:-100}"`) {
		t.Error("coverage gate must default to 100% changed-code coverage")
	}
	if !strings.Contains(coverageGate, `OVERALL_TOLERANCE="${COVERAGE_OVERALL_TOLERANCE:-0}"`) {
		t.Error("coverage gate must reject any reported overall regression")
	}
	if !strings.Contains(coverageGate, `--baseline-profile "$BASELINE_PROFILE"`) {
		t.Error("coverage gate must evaluate the merge-base profile with the candidate checker")
	}
	if strings.Contains(coverageGate, `--overall-profile "$ADDITIONAL_DIFF_PROFILE"`) {
		t.Error("supporting changed-code coverage must not inflate candidate overall coverage")
	}
	if strings.Contains(coverageGate, `go tool cover -func="$BASELINE_PROFILE"`) {
		t.Error("coverage baseline must not use a different coverage calculator")
	}

	aiBehavior := readWorkflow(".github/workflows/ai-behavior-check.yml")
	for _, want := range []string{
		"name: Code Admission — AI Behavior",
		"\n    name: AI Behavior\n",
		"context: 'AI Behavior'",
		"pull_request_target:",
		"pull.head.sha !== expectedHead",
		"pull.base.sha !== expectedBase",
	} {
		if !strings.Contains(aiBehavior, want) {
			t.Errorf("AI Behavior workflow missing contract %q", want)
		}
	}

	integration := readWorkflow(".github/workflows/multi-profile-e2e.yml")
	for _, want := range []string{
		"name: Main Integration — 主干集成",
		"\n    name: Multi-profile E2E\n",
		"branches:",
		"- main",
		"workflow_dispatch:",
	} {
		if !strings.Contains(integration, want) {
			t.Errorf("main integration workflow missing contract %q", want)
		}
	}
	if strings.Contains(integration, "pull_request:") {
		t.Error("complete Multi-profile E2E must not run as a pull-request admission context")
	}
}

func TestChangelogPRGateRejectsUnsafeChanges(t *testing.T) {
	validRelease := `# Changelog

## [Unreleased]

## [1.0.1-beta.1] - 2026-07-17

### Changed

- Valid release note.

## [1.0.0] - 2026-07-01

### Added

- Initial release.
`
	tests := []struct {
		name       string
		changelog  string
		mutate     func(*testing.T, *changelogGateRepo)
		wantOutput string
	}{
		{
			name:      "second changed file",
			changelog: validRelease,
			mutate: func(t *testing.T, repo *changelogGateRepo) {
				changelogGateWrite(t, repo.root, "extra.txt", "extra\n", 0o644)
			},
			wantOutput: "exactly one in-place modification",
		},
		{
			name: "invalid calendar date",
			changelog: strings.Replace(
				validRelease,
				"2026-07-17",
				"2026-02-30",
				1,
			),
			wantOutput: "invalid calendar date",
		},
		{
			name: "duplicate release heading",
			changelog: strings.Replace(
				validRelease,
				"## [1.0.0] - 2026-07-01",
				"## [1.0.1-beta.1] - 2026-07-17\n\n- Duplicate.\n\n## [1.0.0] - 2026-07-01",
				1,
			),
			wantOutput: "exactly one well-formed section",
		},
		{
			name: "missing bullet",
			changelog: strings.Replace(
				validRelease,
				"- Valid release note.",
				"Valid release note.",
				1,
			),
			wantOutput: "at least one bullet",
		},
		{
			name: "placeholder",
			changelog: strings.Replace(
				validRelease,
				"- Valid release note.",
				"- TODO: write release notes.",
				1,
			),
			wantOutput: "must not contain TODO/TBD",
		},
		{
			name: "malformed duplicate unreleased heading",
			changelog: strings.Replace(
				validRelease,
				"## [Unreleased]",
				"## [Unreleased]\n\n## [Unreleased] junk",
				1,
			),
			wantOutput: "exactly one heading",
		},
		{
			name: "preamble change",
			changelog: strings.Replace(
				validRelease,
				"# Changelog",
				"# Release history",
				1,
			),
			wantOutput: "only permits notes inside",
		},
		{
			name:      "rename changelog",
			changelog: changelogGateBase,
			mutate: func(t *testing.T, repo *changelogGateRepo) {
				if err := os.Rename(
					filepath.Join(repo.root, "CHANGELOG.md"),
					filepath.Join(repo.root, "CHANGES.md"),
				); err != nil {
					t.Fatalf("Rename CHANGELOG.md error = %v", err)
				}
			},
			wantOutput: "regular 100644 blob at head",
		},
	}

	for _, test := range tests {
		t.Run(test.name, func(t *testing.T) {
			repo := newChangelogGateRepo(t)
			changelogGateWrite(t, repo.root, "CHANGELOG.md", test.changelog, 0o644)
			if test.mutate != nil {
				test.mutate(t, repo)
			}
			repo.commit(t, test.name)

			output, err := repo.run(t)
			if err == nil {
				t.Fatalf("unsafe change unexpectedly passed:\n%s", output)
			}
			if !strings.Contains(output, test.wantOutput) {
				t.Fatalf("gate output missing %q:\n%s", test.wantOutput, output)
			}
		})
	}
}