package app

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

	"agentu/internal/agent"
	"agentu/internal/session"
	"agentu/pkg/config"
	"agentu/pkg/llm"
)

type startupProvider struct{}

func (p *startupProvider) ChatStream(ctx context.Context, req llm.ChatRequest, emit func(llm.StreamEvent) error) error {
	return emit(llm.StreamEvent{Content: "ok"})
}

func startupTestManager(t *testing.T) (*session.Manager, *agent.Agent) {
	t.Helper()
	cfg := &config.Config{
		Providers: map[string]config.ProviderConfig{
			"one": {
				Name:          "one",
				BaseURL:       "https://one.example.com",
				APIKey:        "sk-test",
				Model:         "model-a",
				Models:        []string{"model-a"},
				Thinking:      "none",
				ThinkingParam: "thinking",
			},
		},
	}
	assistant := agent.New(agent.Options{
		Provider:     &startupProvider{},
		ProviderName: "one",
		Model:        "model-a",
	})
	store, err := session.NewStore(filepath.Join(t.TempDir(), "sessions"))
	if err != nil {
		t.Fatal(err)
	}
	manager, err := session.NewManager(cfg, assistant, nil, store)
	if err != nil {
		t.Fatal(err)
	}
	return manager, assistant
}

func TestInitializeSessionStartsNewByDefault(t *testing.T) {
	manager, assistant := startupTestManager(t)
	if _, err := manager.NewSession(); err != nil {
		t.Fatalf("new session: %v", err)
	}
	savedID := manager.CurrentSessionID()
	assistant.SetMessages([]llm.Message{{Role: llm.RoleUser, Content: "old context"}})
	if err := manager.Save(); err != nil {
		t.Fatalf("save: %v", err)
	}

	if err := initializeSession(manager, ""); err != nil {
		t.Fatalf("initialize: %v", err)
	}
	if manager.CurrentSessionID() == savedID {
		t.Fatalf("default startup resumed latest session %s", savedID)
	}
	for _, msg := range assistant.Messages() {
		if msg.Content == "old context" {
			t.Fatal("default startup carried old context into new session")
		}
	}
}

func TestInitializeSessionResumesExplicitID(t *testing.T) {
	manager, assistant := startupTestManager(t)
	if _, err := manager.NewSession(); err != nil {
		t.Fatalf("new session: %v", err)
	}
	savedID := manager.CurrentSessionID()
	assistant.SetMessages([]llm.Message{{Role: llm.RoleUser, Content: "old context"}})
	if err := manager.Save(); err != nil {
		t.Fatalf("save: %v", err)
	}

	if err := initializeSession(manager, savedID); err != nil {
		t.Fatalf("initialize: %v", err)
	}
	if manager.CurrentSessionID() != savedID {
		t.Fatalf("expected resumed session %s, got %s", savedID, manager.CurrentSessionID())
	}
	found := false
	for _, msg := range assistant.Messages() {
		if msg.Content == "old context" {
			found = true
		}
	}
	if !found {
		t.Fatal("explicit resume did not restore saved context")
	}
}