package cmd_test

// `kettle mirror` is the one command in the tree that has nothing to do with
// issues, and the one that must never fail a caller. Both are tested here.

import (
	"encoding/json"
	"os"
	"path/filepath"
	"strings"
	"testing"
)

func writeDoc(t *testing.T, dir, name, body string) {
	t.Helper()
	if err := os.MkdirAll(dir, 0o755); err != nil {
		t.Fatal(err)
	}
	if err := os.WriteFile(filepath.Join(dir, name), []byte(body), 0o644); err != nil {
		t.Fatal(err)
	}
}

func linkTarget(t *testing.T, path string) string {
	t.Helper()
	target, err := os.Readlink(path)
	if err != nil {
		t.Fatalf("%s is not a symlink: %v", path, err)
	}
	return target
}

// The tree it walks is the working directory, not a project: this must work in
// a directory that has never seen `kettle init`, because the convention it
// maintains has nothing to do with issues.
func TestMirrorNeedsNoProject(t *testing.T) {
	dir := t.TempDir()
	writeDoc(t, dir, "AGENTS.md", "root\n")
	writeDoc(t, filepath.Join(dir, "cli"), "AGENTS.md", "cli\n")

	r := mustRun(t, dir, "mirror")
	if strings.Contains(r.out(), ".kettle") {
		t.Errorf("mirror asked for a project:\n%s", r.out())
	}
	for _, sub := range []string{".", "cli"} {
		if got := linkTarget(t, filepath.Join(dir, sub, "CLAUDE.md")); got != "AGENTS.md" {
			t.Errorf("%s/CLAUDE.md points at %q, want a relative AGENTS.md", sub, got)
		}
	}

	// Idempotent, and it says so rather than printing nothing at all.
	again := mustRun(t, dir, "mirror")
	if !strings.Contains(again.stdout, "nothing to do") {
		t.Errorf("a canonical tree did not report itself clean:\n%s", again.out())
	}
}

func TestMirrorTakesADirectoryArgument(t *testing.T) {
	dir := t.TempDir()
	elsewhere := filepath.Join(dir, "elsewhere")
	writeDoc(t, elsewhere, "AGENTS.md", "there\n")

	mustRun(t, dir, "mirror", elsewhere)
	if _, err := os.Lstat(filepath.Join(elsewhere, "CLAUDE.md")); err != nil {
		t.Errorf("the named directory was not repaired: %v", err)
	}

	if r := run(t, dir, "mirror", filepath.Join(dir, "nowhere")); r.code == 0 {
		t.Errorf("a directory that is not there must be refused:\n%s", r.out())
	}
}

func TestMirrorCheckWritesNothingAndFailsLoudly(t *testing.T) {
	dir := t.TempDir()
	writeDoc(t, dir, "AGENTS.md", "root\n")

	r := run(t, dir, "mirror", "--check")
	if r.code != 1 {
		t.Fatalf("--check exited %d on a tree with work to do, want 1:\n%s", r.code, r.out())
	}
	if !strings.Contains(r.stdout, "would: ") {
		t.Errorf("--check did not say what it would do:\n%s", r.out())
	}
	if _, err := os.Lstat(filepath.Join(dir, "CLAUDE.md")); err == nil {
		t.Error("--check wrote to the tree it was asked about")
	}

	mustRun(t, dir, "mirror")
	if r := run(t, dir, "mirror", "--check"); r.code != 0 {
		t.Errorf("--check exited %d on a canonical tree:\n%s", r.code, r.out())
	}
}

// The refusal, end to end. One of these two files is somebody's writing and no
// rule in this binary knows which, so both survive and the operator is told.
func TestMirrorRefusesTwoDifferentRealFiles(t *testing.T) {
	dir := t.TempDir()
	writeDoc(t, dir, "AGENTS.md", "mine\n")
	writeDoc(t, dir, "CLAUDE.md", "theirs\n")

	r := mustRun(t, dir, "mirror")
	if !strings.Contains(r.stdout, "conflict:") || !strings.Contains(r.stdout, "merge manually") {
		t.Errorf("the conflict was not reported:\n%s", r.out())
	}
	if got := readFile(t, filepath.Join(dir, "AGENTS.md")); got != "mine\n" {
		t.Errorf("AGENTS.md was changed: %q", got)
	}
	if got := readFile(t, filepath.Join(dir, "CLAUDE.md")); got != "theirs\n" {
		t.Errorf("CLAUDE.md was changed: %q", got)
	}
	// A repair run reports the conflict and still exits 0 — the six branches it
	// could fix, it fixed. --check is the one that turns it into a failure.
	if r := run(t, dir, "mirror", "--check"); r.code != 1 {
		t.Errorf("--check exited %d on a conflict, want 1", r.code)
	}
}

// The hook form's whole contract: it cannot fail a Bash call. Every one of these
// is a payload or a state that could plausibly arrive, and every one exits 0.
func TestMirrorHookAlwaysExitsZero(t *testing.T) {
	cases := []struct {
		name  string
		stdin string
		setup func(t *testing.T, dir string)
	}{
		{name: "no payload at all", stdin: ""},
		{name: "a payload that is not JSON", stdin: "not json at all"},
		{name: "an empty object", stdin: "{}"},
		{name: "a payload with keys it does not know", stdin: `{"cwd":".","tool_name":"Bash","future":{"x":1}}`},
		{
			name:  "a tree it cannot resolve",
			stdin: `{"cwd":"/nowhere/at/all"}`,
			setup: func(t *testing.T, dir string) { writeDoc(t, dir, "AGENTS.md", "root\n") },
		},
		{
			name:  "a conflict it must not resolve",
			stdin: `{}`,
			setup: func(t *testing.T, dir string) {
				writeDoc(t, dir, "AGENTS.md", "mine\n")
				writeDoc(t, dir, "CLAUDE.md", "theirs\n")
			},
		},
	}

	for _, tc := range cases {
		t.Run(tc.name, func(t *testing.T) {
			dir := t.TempDir()
			if tc.setup != nil {
				tc.setup(t, dir)
			}
			r := runWith(t, dir, nil, tc.stdin, "mirror", "--hook")
			if r.code != 0 {
				t.Errorf("exited %d — a documentation helper may not break a Bash call:\n%s", r.code, r.out())
			}
		})
	}
}

// What it says when it did something, and what it says when it did not.
func TestMirrorHookReportsOnlyWhenThereIsSomethingToSay(t *testing.T) {
	dir := t.TempDir()
	writeDoc(t, dir, "AGENTS.md", "root\n")

	r := runWith(t, dir, nil, "{}", "mirror", "--hook")
	var out struct {
		HookSpecificOutput struct {
			HookEventName     string `json:"hookEventName"`
			AdditionalContext string `json:"additionalContext"`
		} `json:"hookSpecificOutput"`
	}
	if err := json.Unmarshal([]byte(r.stdout), &out); err != nil {
		t.Fatalf("the hook did not emit JSON: %v\n%s", err, r.out())
	}
	if out.HookSpecificOutput.HookEventName != "PreToolUse" {
		t.Errorf("hookEventName is %q", out.HookSpecificOutput.HookEventName)
	}
	if !strings.Contains(out.HookSpecificOutput.AdditionalContext, "CLAUDE.md") {
		t.Errorf("the report says nothing about what it did:\n%s", out.HookSpecificOutput.AdditionalContext)
	}

	// Silence means the tree was already canonical. A hook that spoke on every
	// Bash call would be noise in every transcript.
	quiet := runWith(t, dir, nil, "{}", "mirror", "--hook")
	if strings.TrimSpace(quiet.stdout) != "" {
		t.Errorf("a canonical tree still produced output:\n%s", quiet.stdout)
	}
}

// CLAUDE_PROJECT_DIR is the harness's own answer to "which tree", and it wins
// over the payload's cwd — a Bash call made from a subdirectory must still
// repair the whole project rather than the corner it was made in.
func TestMirrorHookPrefersTheProjectDirectory(t *testing.T) {
	dir := t.TempDir()
	sub := filepath.Join(dir, "deep", "inside")
	writeDoc(t, dir, "AGENTS.md", "root\n")
	writeDoc(t, sub, "AGENTS.md", "inside\n")

	r := runWith(t, sub, []string{"CLAUDE_PROJECT_DIR=" + dir}, `{"cwd":"`+sub+`"}`, "mirror", "--hook")
	if r.code != 0 {
		t.Fatalf("exited %d:\n%s", r.code, r.out())
	}
	if _, err := os.Lstat(filepath.Join(dir, "CLAUDE.md")); err != nil {
		t.Errorf("the project root was not repaired: %v", err)
	}
}