package agent

import (
	"context"
	"encoding/json"
	"fmt"
	"net/http"
	"net/http/httptest"
	"os"
	"path/filepath"
	"testing"
	"time"

	"github.com/patriceckhart/zot/packages/provider"
)

func TestRefreshLlamaCPPModelsAddsOnlyLoadedModels(t *testing.T) {
	server := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		if r.URL.Path != "/models" {
			http.NotFound(w, r)
			return
		}
		fmt.Fprint(w, `{"data":[{"id":"loaded","status":{"value":"loaded"},"meta":{"n_ctx":32768}},{"id":"offline","status":{"value":"unloaded"}}]}`)
	}))
	defer server.Close()

	t.Setenv("ZOT_HOME", t.TempDir())
	t.Setenv("LLAMA_BASE_URL", "")
	if err := AuthStoreFor().SetEndpointCredential(provider.LlamaCPPProviderID, server.URL, ""); err != nil {
		t.Fatal(err)
	}
	provider.SetManagedModels(nil)
	t.Cleanup(func() { provider.SetManagedModels(nil) })

	if err := RefreshLlamaCPPModels(context.Background()); err != nil {
		t.Fatal(err)
	}
	loaded, err := provider.FindModel(provider.LlamaCPPProviderID, "loaded")
	if err != nil {
		t.Fatal(err)
	}
	if loaded.ContextWindow != 32768 || loaded.BaseURL != server.URL+"/v1" {
		t.Fatalf("loaded model = %+v", loaded)
	}
	if _, err := provider.FindModel(provider.LlamaCPPProviderID, "offline"); err == nil {
		t.Fatal("unloaded model must not be selectable")
	}
}

// TestValidateAndRepairConfig_MismatchedPair simulates the bug from a
// stale /model switch: provider=anthropic but model=kimi-for-coding
// (which belongs to provider=kimi). The validator should rewrite the
// model to anthropic's default and persist.
func TestValidateAndRepairConfig_MismatchedPair(t *testing.T) {
	home := t.TempDir()
	t.Setenv("ZOT_HOME", home)

	must := func(c Config) {
		t.Helper()
		b, _ := json.Marshal(c)
		if err := os.WriteFile(filepath.Join(home, "config.json"), b, 0o644); err != nil {
			t.Fatal(err)
		}
	}
	must(Config{Provider: "anthropic", Model: "kimi-for-coding"})

	ValidateAndRepairConfig()

	out, err := LoadConfig()
	if err != nil {
		t.Fatal(err)
	}
	if out.Provider != "anthropic" {
		t.Errorf("provider not preserved: %q", out.Provider)
	}
	if out.Model == "kimi-for-coding" {
		t.Errorf("model not repaired; still %q", out.Model)
	}
	if out.Model == "" {
		t.Errorf("model not set; expected anthropic default")
	}
}

// TestValidateAndRepairConfig_UnknownProvider resets to anthropic and
// clears the model when the saved provider id isn't recognised
// (e.g. user removed it from a previous build).
func TestValidateAndRepairConfig_UnknownProvider(t *testing.T) {
	home := t.TempDir()
	t.Setenv("ZOT_HOME", home)

	b, _ := json.Marshal(Config{Provider: "made-up-provider", Model: "some-model"})
	_ = os.WriteFile(filepath.Join(home, "config.json"), b, 0o644)

	ValidateAndRepairConfig()

	out, _ := LoadConfig()
	if out.Provider != "anthropic" {
		t.Errorf("provider not reset: %q", out.Provider)
	}
	if out.Model != "" {
		t.Errorf("model not cleared: %q", out.Model)
	}
}

// TestValidateAndRepairConfig_UnknownModel keeps the provider but
// snaps the model to that provider's default when the saved id is no
// longer in the catalog.
func TestValidateAndRepairConfig_UnknownModel(t *testing.T) {
	home := t.TempDir()
	t.Setenv("ZOT_HOME", home)

	b, _ := json.Marshal(Config{Provider: "anthropic", Model: "claude-deleted-model"})
	_ = os.WriteFile(filepath.Join(home, "config.json"), b, 0o644)

	ValidateAndRepairConfig()

	out, _ := LoadConfig()
	if out.Provider != "anthropic" {
		t.Errorf("provider changed: %q", out.Provider)
	}
	if out.Model == "" || out.Model == "claude-deleted-model" {
		t.Errorf("model not repaired: %q", out.Model)
	}
}

func TestValidateAndRepairConfig_DuplicateModelIDValidForConfiguredProvider(t *testing.T) {
	home := t.TempDir()
	t.Setenv("ZOT_HOME", home)

	b, _ := json.Marshal(Config{Provider: "openai-codex", Model: "gpt-5.5"})
	_ = os.WriteFile(filepath.Join(home, "config.json"), b, 0o644)

	ValidateAndRepairConfig()

	out, _ := LoadConfig()
	if out.Provider != "openai-codex" {
		t.Errorf("provider mutated: %q", out.Provider)
	}
	if out.Model != "gpt-5.5" {
		t.Errorf("model mutated: %q", out.Model)
	}
}

func TestModelCacheFetchedAtPreservesCatalogFreshness(t *testing.T) {
	cachedAt := time.Date(2026, time.August, 30, 12, 0, 0, 0, time.UTC)
	now := cachedAt.Add(time.Hour)
	cached := provider.ModelCache{FetchedAt: cachedAt}

	if got := modelCacheFetchedAt(cached, false, now); !got.Equal(cachedAt) {
		t.Fatalf("fresh cache timestamp = %v; want %v", got, cachedAt)
	}
	if got := modelCacheFetchedAt(cached, true, now); !got.Equal(now) {
		t.Fatalf("refreshed cache timestamp = %v; want %v", got, now)
	}
}

func TestMergeOpenRouterPresetsReplacesCachedPresets(t *testing.T) {
	existing := []provider.Model{
		{Provider: "openrouter", ID: "deepseek/deepseek-v4-flash"},
		{Provider: "openrouter", ID: "@preset/old"},
		{Provider: "anthropic", ID: "claude-sonnet-4-5"},
	}
	presets := []provider.Model{
		{Provider: "openrouter", ID: "@preset/flash", DisplayName: "Flash (preset)", ContextWindow: 1000000},
	}
	out := mergeOpenRouterPresets(existing, presets)
	if len(out) != 3 {
		t.Fatalf("got %d models; want 3", len(out))
	}
	var ids []string
	for _, m := range out {
		ids = append(ids, m.Provider+"/"+m.ID)
	}
	want := []string{"openrouter/deepseek/deepseek-v4-flash", "anthropic/claude-sonnet-4-5", "openrouter/@preset/flash"}
	for i, id := range want {
		if ids[i] != id {
			t.Errorf("ids[%d] = %q; want %q", i, ids[i], id)
		}
	}
}

func TestValidateAndRepairConfig_OpenRouterPreservesRoutedModelID(t *testing.T) {
	home := t.TempDir()
	t.Setenv("ZOT_HOME", home)

	want := "deepseek/deepseek-v4-flash"
	b, _ := json.Marshal(Config{Provider: "openrouter", Model: want})
	_ = os.WriteFile(filepath.Join(home, "config.json"), b, 0o644)

	ValidateAndRepairConfig()

	out, _ := LoadConfig()
	if out.Provider != "openrouter" {
		t.Errorf("provider mutated: %q", out.Provider)
	}
	if out.Model != want {
		t.Errorf("routed model id mutated: got %q, want %q", out.Model, want)
	}
}

func TestValidateAndRepairConfig_GatewayPlainUnknownModelStillRepairs(t *testing.T) {
	home := t.TempDir()
	t.Setenv("ZOT_HOME", home)

	b, _ := json.Marshal(Config{Provider: "openrouter", Model: "not-a-routed-model"})
	_ = os.WriteFile(filepath.Join(home, "config.json"), b, 0o644)

	ValidateAndRepairConfig()

	out, _ := LoadConfig()
	if out.Provider != "openrouter" {
		t.Errorf("provider mutated: %q", out.Provider)
	}
	if out.Model == "not-a-routed-model" || out.Model == "" {
		t.Errorf("plain unknown gateway model was not repaired: %q", out.Model)
	}
}

// TestValidateAndRepairConfig_HappyPath leaves a valid config alone.
func TestValidateAndRepairConfig_HappyPath(t *testing.T) {
	home := t.TempDir()
	t.Setenv("ZOT_HOME", home)

	b, _ := json.Marshal(Config{Provider: "anthropic", Model: "claude-sonnet-4-5"})
	_ = os.WriteFile(filepath.Join(home, "config.json"), b, 0o644)

	ValidateAndRepairConfig()

	out, _ := LoadConfig()
	if out.Provider != "anthropic" {
		t.Errorf("provider mutated: %q", out.Provider)
	}
	if out.Model != "claude-sonnet-4-5" {
		t.Errorf("model mutated: %q", out.Model)
	}
}