package app_test

import (
	"errors"
	"io"
	"os"
	"path/filepath"
	"strings"
	"sync"
	"testing"

	"proxyctl/internal/app"
	"proxyctl/internal/profile"
)

func TestProfileConfigurationUsesIsolatedXDGPathOwnerOnlyAndAtomicReplacement(t *testing.T) {
	xdg := t.TempDir()
	t.Setenv("XDG_CONFIG_HOME", xdg)
	path, err := profile.ConfigPath()
	if err != nil {
		t.Fatalf("resolve XDG configuration: %v", err)
	}
	wantPath := filepath.Join(xdg, "proxyctl", "profiles.json")
	if path != wantPath {
		t.Fatalf("configuration path = %q, want %q", path, wantPath)
	}
	application, err := app.New(profile.NewFileStore(path))
	if err != nil {
		t.Fatal(err)
	}
	created := application.Dispatch(app.Intent{Kind: app.CreateProfile, Profile: profile.Profile{
		Name: "private", Mode: profile.SingleMode, SingleURL: "http://alice:secret@proxy.example:8080",
	}})
	if created.Err != nil {
		t.Fatal(created.Err)
	}
	assertMode(t, filepath.Dir(path), 0o700)
	assertMode(t, path, 0o600)
	data, err := os.ReadFile(path)
	if err != nil {
		t.Fatal(err)
	}
	if !strings.Contains(string(data), "\n  \"profiles\"") {
		t.Fatalf("Profile configuration is not human-readable JSON:\n%s", data)
	}

	oldFile, err := os.Open(path)
	if err != nil {
		t.Fatal(err)
	}
	defer oldFile.Close()
	updated := application.Dispatch(app.Intent{Kind: app.UpdateProfile, Name: "private", Profile: profile.Profile{
		Name: "renamed", Mode: profile.SingleMode, SingleURL: "http://alice:new-secret@proxy.example:8080",
	}})
	if updated.Err != nil {
		t.Fatal(updated.Err)
	}
	oldData, err := io.ReadAll(oldFile)
	if err != nil {
		t.Fatal(err)
	}
	newData, err := os.ReadFile(path)
	if err != nil {
		t.Fatal(err)
	}
	if !strings.Contains(string(oldData), `"name": "private"`) || !strings.Contains(string(newData), `"name": "renamed"`) {
		t.Fatalf("configuration was not atomically replaced; old=%s new=%s", oldData, newData)
	}
	matches, err := filepath.Glob(filepath.Join(filepath.Dir(path), ".profiles-*"))
	if err != nil || len(matches) != 0 {
		t.Fatalf("temporary Profile files left behind: %v (%v)", matches, err)
	}
}

type committedErrorStore struct {
	state     profile.State
	loadCalls int
}

func (s *committedErrorStore) Load() (profile.State, error) {
	s.loadCalls++
	return s.state, nil
}

func (s *committedErrorStore) Mutate(change func(profile.State) (profile.State, error)) (profile.State, error) {
	next, err := change(s.state)
	if err != nil {
		return s.state, err
	}
	s.state = next
	return next, &profile.CommitError{Err: errors.New("injected directory sync failure")}
}

func TestApplicationReloadsStateAfterCommittedDurabilityError(t *testing.T) {
	store := &committedErrorStore{}
	application, err := app.New(store)
	if err != nil {
		t.Fatal(err)
	}
	result := application.Dispatch(app.Intent{Kind: app.CreateProfile, Profile: profile.Profile{
		Name: "committed", Mode: profile.SingleMode, SingleURL: "http://proxy.example:8080",
	}})
	var committed *profile.CommitError
	if !errors.As(result.Err, &committed) {
		t.Fatalf("mutation error = %v, want committed durability error", result.Err)
	}
	if store.loadCalls != 3 {
		t.Fatalf("Load calls = %d, want startup, pre-mutation, and post-commit reloads", store.loadCalls)
	}
	if len(result.Snapshot.Profiles) != 1 || result.Snapshot.Profiles[0].Name != "committed" {
		t.Fatalf("Application snapshot after committed error = %#v", result.Snapshot)
	}
}

func TestConcurrentApplicationsMutateLatestStateWithoutLostUpdates(t *testing.T) {
	path := filepath.Join(t.TempDir(), "proxyctl", "profiles.json")
	first, err := app.New(profile.NewFileStore(path))
	if err != nil {
		t.Fatal(err)
	}
	second, err := app.New(profile.NewFileStore(path))
	if err != nil {
		t.Fatal(err)
	}

	start := make(chan struct{})
	results := make(chan app.Result, 2)
	var workers sync.WaitGroup
	for application, name := range map[*app.Application]string{first: "home", second: "office"} {
		workers.Add(1)
		go func() {
			defer workers.Done()
			<-start
			results <- application.Dispatch(app.Intent{Kind: app.CreateProfile, Profile: profile.Profile{
				Name: name, Mode: profile.SingleMode, SingleURL: "http://proxy.example:8080",
			}})
		}()
	}
	close(start)
	workers.Wait()
	close(results)
	for result := range results {
		if result.Err != nil {
			t.Fatalf("concurrent mutation: %v", result.Err)
		}
	}

	reloaded, err := app.New(profile.NewFileStore(path))
	if err != nil {
		t.Fatal(err)
	}
	if got := len(reloaded.Snapshot().Profiles); got != 2 {
		t.Fatalf("persisted Profiles = %d, want both concurrent updates", got)
	}
	assertMode(t, path+".lock", 0o600)
}

func TestLoadSecuresExistingSecretBearingConfiguration(t *testing.T) {
	path := filepath.Join(t.TempDir(), "proxyctl", "profiles.json")
	if err := os.MkdirAll(filepath.Dir(path), 0o700); err != nil {
		t.Fatal(err)
	}
	contents := `{"profiles":[{"name":"private","mode":"single","singleUrl":"http://alice:secret@proxy.example:8080"}]}`
	if err := os.WriteFile(path, []byte(contents), 0o644); err != nil {
		t.Fatal(err)
	}
	if _, err := app.New(profile.NewFileStore(path)); err != nil {
		t.Fatalf("load existing configuration: %v", err)
	}
	assertMode(t, path, 0o600)
	if _, err := os.Lstat(path + ".lock"); !errors.Is(err, os.ErrNotExist) {
		t.Fatalf("view-only Load unexpectedly created a lock: %v", err)
	}
}

func assertMode(t *testing.T, path string, want os.FileMode) {
	t.Helper()
	info, err := os.Stat(path)
	if err != nil {
		t.Fatal(err)
	}
	if got := info.Mode().Perm(); got != want {
		t.Fatalf("mode for %s = %#o, want %#o", path, got, want)
	}
}