package notes

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

// newBrain lays out a tree shaped like the live one: a git dir, note dirs,
// and the non-note areas that must never be reachable.
func newBrain(t *testing.T) string {
	t.Helper()
	dir := t.TempDir()
	for _, d := range []string{
		".git/hooks", "knowledge", "wiki/homelab/facts", "archive/claude-sessions/koala",
		"sessions", "raw", ".obsidian",
	} {
		if err := os.MkdirAll(filepath.Join(dir, d), 0o755); err != nil {
			t.Fatal(err)
		}
	}
	write := func(p, s string) {
		t.Helper()
		if err := os.WriteFile(filepath.Join(dir, p), []byte(s), 0o644); err != nil {
			t.Fatal(err)
		}
	}
	write("CLAUDE.md", "# instructions\n")
	write("log.md", "ignored scratch\n")
	write("knowledge/note.md", "# note\n")
	write("wiki/homelab/facts/f.md", "# fact\n")
	write("wiki/homelab/_index.md", "# index\n")
	write("archive/claude-sessions/koala/session-1.md", "verbatim transcript\n")
	write("sessions/s.jsonl", "{}\n")
	write(".git/hooks/post-commit", "#!/bin/sh\n")
	return dir
}

func TestResolve_AcceptsNotePaths(t *testing.T) {
	dir := newBrain(t)
	for _, p := range []string{"knowledge/note.md", "wiki/homelab/facts/f.md"} {
		got, err := Resolve(dir, p, ScopeNotes)
		if err != nil {
			t.Errorf("Resolve(%q): %v", p, err)
			continue
		}
		if !strings.HasPrefix(got.Abs, dir) {
			t.Errorf("Resolve(%q).Abs = %q, want inside %q", p, got.Abs, dir)
		}
	}
}

func TestResolve_RefusesEscapesAndNonNoteAreas(t *testing.T) {
	dir := newBrain(t)

	// Canonicalisation must happen BEFORE the allowlist check. A prefix test
	// on the raw argument accepts every one of these: "knowledge/..%2f" style
	// inputs collapse to .git, and .git/hooks/post-commit is executed by
	// brain-sync inside a pod holding the Gitea push credentials.
	refuse := []string{
		"knowledge/../.git/hooks/post-commit",
		"wiki/../.git/config",
		"./knowledge/../.git/config",
		"knowledge//../.git/config",
		"../../etc/passwd",
		"/etc/passwd",
		".git/config",
		"archive/claude-sessions/koala/session-1.md", // verbatim transcripts
		"sessions/s.jsonl",
		"raw/x.md",
		".obsidian/workspace.json",
		"log.md",                 // gitignored: an edit here would never sync (brain#2)
		"wiki/homelab/_index.md", // generated; brain-sync resolves it in origin's favour
		"knowledge/note.txt",     // not markdown
		"CLAUDE.md",              // root file — not reachable in the notes scope
	}
	for _, p := range refuse {
		if _, err := Resolve(dir, p, ScopeNotes); err == nil {
			t.Errorf("Resolve(%q) = nil error, want refusal", p)
		}
	}
}

func TestResolve_RootScopeAdmitsOnlyNamedFiles(t *testing.T) {
	dir := newBrain(t)

	if _, err := Resolve(dir, "CLAUDE.md", ScopeRoot); err != nil {
		t.Errorf("Resolve(CLAUDE.md, ScopeRoot): %v", err)
	}
	// log.md is the reason this is an exact-name list and not "root *.md":
	// it is gitignored, so an edit would apply locally and never reach gitea.
	for _, p := range []string{"log.md", "AGENTS.md", "knowledge/note.md", ".git/config"} {
		if _, err := Resolve(dir, p, ScopeRoot); err == nil {
			t.Errorf("Resolve(%q, ScopeRoot) = nil error, want refusal", p)
		}
	}
}

func TestResolve_RefusesSymlinkedTargets(t *testing.T) {
	dir := newBrain(t)
	outside := filepath.Join(t.TempDir(), "secret.md")
	if err := os.WriteFile(outside, []byte("secret\n"), 0o644); err != nil {
		t.Fatal(err)
	}
	// The tree is Syncthing-managed, so a symlink can appear without anyone
	// adding one deliberately. Containment must survive it.
	if err := os.Symlink(outside, filepath.Join(dir, "knowledge/link.md")); err != nil {
		t.Skipf("symlinks unavailable: %v", err)
	}
	if _, err := Resolve(dir, "knowledge/link.md", ScopeNotes); err == nil {
		t.Error("Resolve followed a symlink out of the brain dir")
	}

	if err := os.Symlink(filepath.Dir(outside), filepath.Join(dir, "wiki/escape")); err != nil {
		t.Skipf("symlinks unavailable: %v", err)
	}
	if _, err := Resolve(dir, "wiki/escape/secret.md", ScopeNotes); err == nil {
		t.Error("Resolve followed a symlinked directory out of the brain dir")
	}
}

func TestResolve_RefusesWhenTheTreeIsNotTheSyncSource(t *testing.T) {
	// brain#2 was "wrote to a directory the sync does not commit from". No
	// code review prevents that recurring — a wrong INGEST_BRAIN_DIR in a
	// future manifest reintroduces it and every unit test still passes. So
	// assert the property at runtime, the way brain-sync itself does.
	dir := t.TempDir()
	if err := os.MkdirAll(filepath.Join(dir, "knowledge"), 0o755); err != nil {
		t.Fatal(err)
	}
	if err := os.WriteFile(filepath.Join(dir, "knowledge/note.md"), []byte("x"), 0o644); err != nil {
		t.Fatal(err)
	}
	// Reads are fine anywhere; the guard belongs to writes.
	if _, err := Resolve(dir, "knowledge/note.md", ScopeNotes); err != nil {
		t.Fatalf("Resolve should not require .git for a read: %v", err)
	}
	_, err := Edit(dir, "knowledge/note.md", "x", "y", ScopeNotes)
	if err == nil {
		t.Fatal("Edit accepted a tree with no .git — the write would never be committed")
	}
	if !strings.Contains(err.Error(), "sync source") {
		t.Errorf("error should name the cause, got %v", err)
	}
}