// Test helpers for Hexai CLI tests (stdin swapping and fake LLM clients/streamers).
package hexaicli

import (
	"context"
	"os"
	"path/filepath"
	"testing"

	"codeberg.org/snonux/hexai/internal/llm"
)

func TestMain(m *testing.M) {
	cacheDir, err := os.MkdirTemp("", "hexai-cli-cache-*")
	if err != nil {
		panic(err)
	}
	oldCacheHome := os.Getenv("XDG_CACHE_HOME")
	_ = os.Setenv("XDG_CACHE_HOME", cacheDir)
	code := m.Run()
	if oldCacheHome == "" {
		_ = os.Unsetenv("XDG_CACHE_HOME")
	} else {
		_ = os.Setenv("XDG_CACHE_HOME", oldCacheHome)
	}
	_ = os.RemoveAll(cacheDir)
	os.Exit(code)
}

// setStdin sets os.Stdin from a string and returns a restore func and reader.
func setStdin(t *testing.T, content string) (func(), *os.File) {
	t.Helper()
	tmpDir := t.TempDir()
	fpath := filepath.Join(tmpDir, "stdin.txt")
	if err := os.WriteFile(fpath, []byte(content), 0o600); err != nil {
		t.Fatalf("write temp stdin: %v", err)
	}
	f, err := os.Open(fpath)
	if err != nil {
		t.Fatalf("open temp stdin: %v", err)
	}
	old := os.Stdin
	os.Stdin = f
	restore := func() {
		if err := f.Close(); err != nil {
			t.Errorf("failed to close temp stdin file: %v", err)
		}
		os.Stdin = old
	}
	return restore, f
}

// fakeClient implements llm.Client for tests.
type fakeClient struct {
	name    string
	model   string
	resp    string
	gotMsgs []llm.Message
}

func (f *fakeClient) Chat(ctx context.Context, messages []llm.Message, opts ...llm.RequestOption) (string, error) {
	f.gotMsgs = append([]llm.Message{}, messages...)
	return f.resp, nil
}
func (f fakeClient) Name() string         { return f.name }
func (f fakeClient) DefaultModel() string { return f.model }

// fakeStreamer implements llm.Streamer over fakeClient.
type fakeStreamer struct {
	fakeClient
	chunks []string
	sMsgs  []llm.Message
}

func (s *fakeStreamer) ChatStream(ctx context.Context, messages []llm.Message, onDelta func(string), opts ...llm.RequestOption) error {
	s.sMsgs = append([]llm.Message{}, messages...)
	for _, c := range s.chunks {
		onDelta(c)
	}
	return nil
}

func writeConfigString(t *testing.T, path string, contents string) {
	t.Helper()
	if err := os.MkdirAll(filepath.Dir(path), 0o755); err != nil {
		t.Fatalf("mkdir: %v", err)
	}
	if err := os.WriteFile(path, []byte(contents), 0o644); err != nil {
		t.Fatalf("write: %v", err)
	}
}

func testingTempDir(t *testing.T) string { t.Helper(); return t.TempDir() }