package todos

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

const fixture = `{
  "id": "deadbeef",
  "title": "A brace } and quote \"",
  "tags": ["qa", "pi"],
  "status": "in_progress",
  "created_at": "2026-01-25T17:00:00.000Z",
  "assigned_to_session": "session.json"
}

## Details

Keep {braces} in the body.
`

func TestParseAndSerializePiFixture(t *testing.T) {
	todo, err := Parse("deadbeef", []byte(fixture))
	if err != nil {
		t.Fatal(err)
	}
	if todo.ID != "deadbeef" || todo.Title != `A brace } and quote "` || todo.Status != "in_progress" || todo.AssignedToSession != "session.json" || !strings.Contains(todo.Body, "{braces}") {
		t.Fatalf("unexpected parsed todo: %+v", todo)
	}
	data, err := Serialize(todo)
	if err != nil {
		t.Fatal(err)
	}
	again, err := Parse(todo.ID, data)
	if err != nil || again.Title != todo.Title || again.Status != todo.Status || again.Body != todo.Body {
		t.Fatalf("round trip mismatch: %+v, %v", again, err)
	}
}

func TestCreateUpdateAndList(t *testing.T) {
	dir := filepath.Join(t.TempDir(), ".pi", "todos")
	if items, err := List(dir); err != nil || len(items) != 0 {
		t.Fatalf("missing directory should be empty: %v, %v", items, err)
	}
	created, err := Create(dir, Todo{Title: "First", Body: "hello\n"})
	if err != nil || !idPattern.MatchString(created.ID) || created.Status != "open" || created.CreatedAt == "" {
		t.Fatalf("unexpected create: %+v, %v", created, err)
	}
	loaded, err := Read(dir, created.ID)
	if err != nil || loaded.Title != "First" || loaded.Body != "hello\n" {
		t.Fatalf("unexpected read: %+v, %v", loaded, err)
	}
	loaded.Title = "Changed"
	loaded.Status = "blocked" // Pi supports statuses besides open/closed
	loaded.Tags = []string{"test"}
	loaded.AssignedToSession = "session.json"
	if err := Update(dir, loaded); err != nil {
		t.Fatal(err)
	}
	items, err := List(dir)
	if err != nil || len(items) != 1 || items[0].Title != "Changed" || items[0].Status != "blocked" || items[0].CreatedAt != created.CreatedAt || items[0].AssignedToSession != "" {
		t.Fatalf("unexpected update: %+v, %v", items, err)
	}
	if _, err := os.Stat(filepath.Join(dir, created.ID+".lock")); !errors.Is(err, os.ErrNotExist) {
		t.Fatalf("lock left behind: %v", err)
	}
}

func TestLockedFileUnchanged(t *testing.T) {
	dir := t.TempDir()
	path := filepath.Join(dir, "deadbeef.md")
	if err := os.WriteFile(path, []byte(fixture), 0600); err != nil {
		t.Fatal(err)
	}
	if err := os.WriteFile(filepath.Join(dir, "deadbeef.lock"), []byte(`{"session":"other"}`), 0600); err != nil {
		t.Fatal(err)
	}
	err := Update(dir, Todo{ID: "deadbeef", Title: "Changed"})
	if !errors.Is(err, ErrLocked) {
		t.Fatalf("expected lock error: %v", err)
	}
	content, _ := os.ReadFile(path)
	if string(content) != fixture {
		t.Fatal("locked file was changed")
	}
}

func TestUpdatePreservesAssignment(t *testing.T) {
	dir := t.TempDir()
	if err := os.WriteFile(filepath.Join(dir, "deadbeef.md"), []byte(fixture), 0600); err != nil {
		t.Fatal(err)
	}
	if err := Update(dir, Todo{ID: "deadbeef", Title: "Edited", Body: "text"}); err != nil {
		t.Fatal(err)
	}
	result, err := Read(dir, "deadbeef")
	if err != nil || result.AssignedToSession != "session.json" || result.CreatedAt != "2026-01-25T17:00:00.000Z" || result.Status != "in_progress" || len(result.Tags) != 2 {
		t.Fatalf("metadata lost: %+v, %v", result, err)
	}
}

func TestSerializePreservesBodyIndentation(t *testing.T) {
	data, err := Serialize(Todo{ID: "deadbeef", Body: "\n  indented text\n"})
	if err != nil || !strings.HasSuffix(string(data), "\n\n  indented text\n") {
		t.Fatalf("indentation lost: %s, %v", data, err)
	}
}

func TestMalformedAndUnsafeIDs(t *testing.T) {
	if _, err := Parse("../bad", []byte(fixture)); err == nil {
		t.Fatal("unsafe ID accepted")
	}
	if _, err := Parse("deadbeef", []byte(`{bad`)); err == nil {
		t.Fatal("bad JSON accepted")
	}
	if _, err := Parse("deadbeef", []byte(`{"id":"cafebabe"}`)); err == nil {
		t.Fatal("mismatched ID accepted")
	}
	dir := t.TempDir()
	if err := os.WriteFile(filepath.Join(dir, "deadbeef.md"), []byte(`{bad`), 0600); err != nil {
		t.Fatal(err)
	}
	if _, err := List(dir); err == nil {
		t.Fatal("malformed file silently ignored")
	}
}