package hexaicli

import (
	"bytes"
	"context"
	"io"
	"path/filepath"
	"strings"
	"testing"

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

type failingReader struct{ err error }

func (f failingReader) Read([]byte) (int, error) { return 0, f.err }

func TestReadInput_Combinations(t *testing.T) {
	// stdin + arg
	restore, f := setStdin(t, "from-stdin")
	defer restore()
	s, err := readInput(f, []string{"from-arg"})
	if err != nil || !strings.HasPrefix(s, "from-arg:\n\nfrom-stdin") {
		t.Fatalf("stdin+arg failed: %q %v", s, err)
	}
	// stdin only
	restore2, f2 := setStdin(t, "from-stdin")
	defer restore2()
	s, err = readInput(f2, nil)
	if err != nil || s != "from-stdin" {
		t.Fatalf("stdin only failed: %q %v", s, err)
	}
	// arg only
	s, err = readInput(strings.NewReader(""), []string{"arg1", "arg2"})
	if err != nil || s != "arg1 arg2" {
		t.Fatalf("arg only failed: %q %v", s, err)
	}
	// no input
	restore3, f3 := setStdin(t, "")
	defer restore3()
	_, err = readInput(f3, nil)
	if err == nil {
		t.Fatalf("expected error for no input")
	}
}

func TestReadInput_PropagatesStdinError(t *testing.T) {
	restore, _ := setStdin(t, "ignored")
	defer restore()
	bad := failingReader{err: io.ErrUnexpectedEOF}
	if _, err := readInput(bad, nil); err == nil || !strings.Contains(err.Error(), "failed to read stdin") {
		t.Fatalf("expected stdin read error, got %v", err)
	}
}

func TestBuildMessages_Explain(t *testing.T) {
	msgs := buildMessages("please explain this")
	if len(msgs) != 2 || msgs[0].Role != "system" || !strings.Contains(strings.ToLower(msgs[0].Content), "explanation") {
		t.Fatalf("unexpected system prompt: %#v", msgs)
	}
}

func TestBuildMessages_Default(t *testing.T) {
	msgs := buildMessages("just do it")
	if len(msgs) != 2 || msgs[0].Role != "system" || strings.Contains(msgs[0].Content, "requested an explanation") {
		t.Fatalf("unexpected system prompt: %#v", msgs)
	}
}

func TestRunChat_StreamAndNonStream(t *testing.T) {
	// stream path
	fc := &fakeStreamer{fakeClient: fakeClient{name: "p", model: "m"}, chunks: []string{"H", "i", "!"}}
	var out, errb bytes.Buffer
	if err := runChat(context.Background(), fc, buildMessages("hello"), "hello", &out, &errb); err != nil {
		t.Fatalf("stream: %v", err)
	}
	if out.String() != "Hi!" || !strings.Contains(errb.String(), "provider=p model=m") {
		t.Fatalf("bad output or summary: %q %q", out.String(), errb.String())
	}
	// non-stream path
	fc2 := &fakeClient{name: "p2", model: "m2", resp: "Yo"}
	out.Reset()
	errb.Reset()
	if err := runChat(context.Background(), fc2, buildMessages("hello"), "hello", &out, &errb); err != nil {
		t.Fatalf("non-stream: %v", err)
	}
	if out.String() != "Yo" || !strings.Contains(errb.String(), "provider=p2 model=m2") {
		t.Fatalf("bad output or summary (non-stream)")
	}
}

type clientErr struct{ name, model string }

func (c clientErr) Chat(context.Context, []llm.Message, ...llm.RequestOption) (string, error) {
	return "", io.EOF
}
func (c clientErr) Name() string         { return c.name }
func (c clientErr) DefaultModel() string { return c.model }

func TestRunChat_ErrorPaths(t *testing.T) {
	ctx := context.Background()
	out, errb := &bytes.Buffer{}, &bytes.Buffer{}
	if err := runChat(ctx, clientErr{"p", "m"}, buildMessages("hi"), "hi", out, errb); err == nil {
		t.Fatalf("expected error from Chat")
	}
}

func TestRunWithClient_ErrorPrint(t *testing.T) {
	var out, errb bytes.Buffer
	err := RunWithClient(context.Background(), []string{"hi"}, strings.NewReader(""), &out, &errb, clientErr{"p", "m"})
	if err == nil {
		t.Fatalf("expected error")
	}
	if !strings.Contains(errb.String(), "hexai: error:") {
		t.Fatalf("expected error line, got %q", errb.String())
	}
}

func TestRun_OpenAI_NoKey_ShowsError(t *testing.T) {
	dir := testingTempDir(t)
	// write config with provider=openai
	writeTOML(t, filepath.Join(dir, "hexai", "config.toml"), map[string]string{"provider": "openai", "openai_model": "gpt-x"})
	t.Setenv("XDG_CONFIG_HOME", dir)
	// Ensure no OpenAI API key is present in environment
	t.Setenv("HEXAI_OPENAI_API_KEY", "")
	t.Setenv("OPENAI_API_KEY", "")
	var out, errb bytes.Buffer
	// Run expects parsed flags; here args irrelevant
	err := Run(context.Background(), []string{"hello"}, strings.NewReader(""), &out, &errb)
	if err == nil {
		t.Fatalf("expected error due to missing API key")
	}
	// Accept either explicit "LLM disabled" or a generic provider error emitted by Run.
	if !(strings.Contains(errb.String(), "LLM disabled") || strings.Contains(errb.String(), "openai error") || strings.Contains(errb.String(), "hexai: error:")) {
		t.Fatalf("expected disabled-or-error message, got %q", errb.String())
	}
}

func TestPrintProviderInfo(t *testing.T) {
	var b bytes.Buffer
	printProviderInfo(&b, &fakeClient{name: "x", model: "y"})
	if !strings.Contains(b.String(), "provider=x model=y") {
		t.Fatalf("missing provider line: %q", b.String())
	}
}

func TestNewClientFromConfig_Ollama(t *testing.T) {
	cfg := appconfig.App{Provider: "ollama", OllamaBaseURL: "http://x", OllamaModel: "m"}
	c, err := newClientFromConfig(cfg)
	if err != nil || c == nil {
		t.Fatalf("expected client: %v %v", c, err)
	}
}

func TestNewClientFromConfig_OpenAI_MissingKey(t *testing.T) {
	cfg := appconfig.App{Provider: "openai", OpenAIBaseURL: "https://api", OpenAIModel: "gpt"}
	t.Setenv("HEXAI_OPENAI_API_KEY", "")
	t.Setenv("OPENAI_API_KEY", "")
	if _, err := newClientFromConfig(cfg); err == nil {
		t.Fatalf("expected error for missing openai key")
	}
}