package llamaswap

import (
	"context"
	"encoding/json"
	"errors"
	"net/http"
	"net/http/httptest"
	"testing"

	"gitea.stevedudenhoeffer.com/steve/majordomo/imagegen"
	"gitea.stevedudenhoeffer.com/steve/majordomo/llm"
)

// 1x1 transparent PNG, base64 (used to assert image decoding end-to-end).
const onePixelPNG = "iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAQAAAC1HAwCAAAAC0lEQVR42mNk+M9QDwADhgGAWjR9awAAAABJRU5ErkJggg=="

func TestChatDelegatesToOpenAI(t *testing.T) {
	var gotPath, gotAuth string
	var gotBody map[string]any
	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		gotPath = r.URL.Path
		gotAuth = r.Header.Get("Authorization")
		_ = json.NewDecoder(r.Body).Decode(&gotBody)
		w.Header().Set("Content-Type", "application/json")
		_, _ = w.Write([]byte(`{"choices":[{"message":{"role":"assistant","content":"hi"},"finish_reason":"stop"}]}`))
	}))
	defer srv.Close()

	p := New(WithBaseURL(srv.URL), WithToken("test-token"), WithHTTPClient(srv.Client()))
	m, err := p.Model("qwen3:14b")
	if err != nil {
		t.Fatalf("Model: %v", err)
	}
	resp, err := m.Generate(context.Background(), llm.Request{
		Messages:  []llm.Message{llm.UserText("hello")},
		MaxTokens: 64,
	})
	if err != nil {
		t.Fatalf("Generate: %v", err)
	}
	if resp.Text() != "hi" {
		t.Errorf("Text = %q, want %q", resp.Text(), "hi")
	}
	if gotPath != "/v1/chat/completions" {
		t.Errorf("path = %q, want /v1/chat/completions", gotPath)
	}
	if gotAuth != "Bearer test-token" {
		t.Errorf("auth = %q, want Bearer test-token", gotAuth)
	}
	// llama.cpp's OpenAI shim wants the legacy max_tokens field.
	if _, ok := gotBody["max_tokens"]; !ok {
		t.Errorf("request missing max_tokens (legacy); body=%v", gotBody)
	}
	if _, ok := gotBody["max_completion_tokens"]; ok {
		t.Errorf("request used max_completion_tokens; want legacy max_tokens")
	}
}

func TestChatNoTokenSendsPlaceholder(t *testing.T) {
	var gotAuth string
	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		gotAuth = r.Header.Get("Authorization")
		_, _ = w.Write([]byte(`{"choices":[{"message":{"content":"ok"},"finish_reason":"stop"}]}`))
	}))
	defer srv.Close()

	p := New(WithBaseURL(srv.URL), WithHTTPClient(srv.Client())) // no token
	m, _ := p.Model("m")
	if _, err := m.Generate(context.Background(), llm.Request{Messages: []llm.Message{llm.UserText("x")}}); err != nil {
		t.Fatalf("Generate: %v", err)
	}
	// Keyless local llama-swap: a placeholder bearer it ignores, never a blank
	// that the openai client would reject as a synthetic 401.
	if gotAuth != "Bearer no-key" {
		t.Errorf("auth = %q, want Bearer no-key", gotAuth)
	}
}

func TestModelNoBaseURL(t *testing.T) {
	if _, err := New().Model("m"); err == nil {
		t.Fatal("expected error for missing base URL")
	}
	if _, err := New().ImageModel("m"); err == nil {
		t.Fatal("expected error for missing base URL (image)")
	}
}

func TestListModels(t *testing.T) {
	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		if r.URL.Path != "/v1/models" {
			t.Errorf("path = %q", r.URL.Path)
		}
		_, _ = w.Write([]byte(`{"object":"list","data":[{"id":"qwen3:14b","object":"model","owned_by":"llama-swap"},{"id":"sd","object":"model"}]}`))
	}))
	defer srv.Close()

	p := New(WithBaseURL(srv.URL), WithHTTPClient(srv.Client()))
	models, err := p.ListModels(context.Background())
	if err != nil {
		t.Fatalf("ListModels: %v", err)
	}
	if len(models) != 2 || models[0].ID != "qwen3:14b" {
		t.Fatalf("models = %+v", models)
	}
}

func TestUnload(t *testing.T) {
	var gotPath, gotMethod string
	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		gotPath, gotMethod = r.URL.Path, r.Method
		w.WriteHeader(http.StatusOK)
	}))
	defer srv.Close()

	p := New(WithBaseURL(srv.URL), WithHTTPClient(srv.Client()))
	if err := p.Unload(context.Background(), "qwen3:14b"); err != nil {
		t.Fatalf("Unload: %v", err)
	}
	if gotMethod != http.MethodPost || gotPath != "/api/models/unload/qwen3:14b" {
		t.Errorf("got %s %s", gotMethod, gotPath)
	}

	if err := p.Unload(context.Background(), ""); err != nil {
		t.Fatalf("Unload all: %v", err)
	}
	if gotPath != "/api/models/unload" {
		t.Errorf("unload-all path = %q", gotPath)
	}

	// A model id with a path separator is rejected before any request.
	if err := p.Unload(context.Background(), "../admin"); err == nil {
		t.Error("expected error for model id with path separator")
	}
}

func TestManagementNoBaseURL(t *testing.T) {
	p := New() // no base URL
	if _, err := p.ListModels(context.Background()); err == nil {
		t.Error("ListModels: expected error for missing base URL")
	}
	if _, err := p.Running(context.Background()); err == nil {
		t.Error("Running: expected error for missing base URL")
	}
	if err := p.Unload(context.Background(), "m"); err == nil {
		t.Error("Unload: expected error for missing base URL")
	}
}

func TestRunningRaw(t *testing.T) {
	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		_, _ = w.Write([]byte(`{"running":["qwen3:14b"]}`))
	}))
	defer srv.Close()

	p := New(WithBaseURL(srv.URL), WithHTTPClient(srv.Client()))
	raw, err := p.Running(context.Background())
	if err != nil {
		t.Fatalf("Running: %v", err)
	}
	if string(raw) != `{"running":["qwen3:14b"]}` {
		t.Errorf("raw = %s", raw)
	}
}

func TestImageGenerate(t *testing.T) {
	var gotBody map[string]any
	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		if r.URL.Path != "/v1/images/generations" {
			t.Errorf("path = %q", r.URL.Path)
		}
		_ = json.NewDecoder(r.Body).Decode(&gotBody)
		_, _ = w.Write([]byte(`{"created":1,"data":[{"b64_json":"` + onePixelPNG + `"}]}`))
	}))
	defer srv.Close()

	p := New(WithBaseURL(srv.URL), WithHTTPClient(srv.Client()))
	im, err := p.ImageModel("sd")
	if err != nil {
		t.Fatalf("ImageModel: %v", err)
	}
	res, err := im.Generate(context.Background(), imagegen.Request{Prompt: "a red bicycle"}, imagegen.WithSize("512x512"))
	if err != nil {
		t.Fatalf("Generate: %v", err)
	}
	if len(res.Images) != 1 {
		t.Fatalf("images = %d, want 1", len(res.Images))
	}
	if res.Images[0].MIME != "image/png" {
		t.Errorf("MIME = %q, want image/png", res.Images[0].MIME)
	}
	if len(res.Images[0].Data) == 0 {
		t.Error("decoded image has no bytes")
	}
	// response_format must be forced to b64_json, and options applied.
	if gotBody["response_format"] != "b64_json" {
		t.Errorf("response_format = %v, want b64_json", gotBody["response_format"])
	}
	if gotBody["size"] != "512x512" {
		t.Errorf("size = %v, want 512x512", gotBody["size"])
	}
}

func TestImageGenerateEmptyPrompt(t *testing.T) {
	p := New(WithBaseURL("http://example.invalid"))
	im, _ := p.ImageModel("sd")
	_, err := im.Generate(context.Background(), imagegen.Request{Prompt: "  "})
	if !errors.Is(err, llm.ErrUnsupported) {
		t.Errorf("err = %v, want ErrUnsupported", err)
	}
}

func TestAPIErrorClassifies(t *testing.T) {
	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		w.WriteHeader(http.StatusTooManyRequests)
		_, _ = w.Write([]byte(`{"error":{"message":"slow down","code":"rate_limited"}}`))
	}))
	defer srv.Close()

	p := New(WithBaseURL(srv.URL), WithHTTPClient(srv.Client()))
	_, err := p.ListModels(context.Background())
	if err == nil {
		t.Fatal("expected error")
	}
	var apiErr *llm.APIError
	if !errors.As(err, &apiErr) {
		t.Fatalf("err type = %T, want *llm.APIError", err)
	}
	if apiErr.Status != http.StatusTooManyRequests || apiErr.Code != "rate_limited" {
		t.Errorf("apiErr = %+v", apiErr)
	}
	if llm.Classify(err) != llm.ClassTransient {
		t.Errorf("429 should classify transient")
	}
}