package llm

import (
	"context"
	"errors"
	"testing"

	"gitea.stevedudenhoeffer.com/steve/go-llm/v2/provider"
)

type testPerson struct {
	Name string `json:"name" description:"The person's name"`
	Age  int    `json:"age" description:"The person's age"`
}

func TestGenerate(t *testing.T) {
	mp := newMockProvider(provider.Response{
		ToolCalls: []provider.ToolCall{
			{
				ID:        "call_1",
				Name:      "structured_output",
				Arguments: `{"name":"Alice","age":30}`,
			},
		},
	})
	model := newMockModel(mp)

	result, err := Generate[testPerson](context.Background(), model, "Tell me about Alice")
	if err != nil {
		t.Fatalf("unexpected error: %v", err)
	}
	if result.Name != "Alice" {
		t.Errorf("expected name 'Alice', got %q", result.Name)
	}
	if result.Age != 30 {
		t.Errorf("expected age 30, got %d", result.Age)
	}

	// Verify the tool was sent in the request
	req := mp.lastRequest()
	if len(req.Tools) != 1 {
		t.Fatalf("expected 1 tool, got %d", len(req.Tools))
	}
	if req.Tools[0].Name != "structured_output" {
		t.Errorf("expected tool name 'structured_output', got %q", req.Tools[0].Name)
	}
}

func TestGenerateWith(t *testing.T) {
	mp := newMockProvider(provider.Response{
		ToolCalls: []provider.ToolCall{
			{
				ID:        "call_1",
				Name:      "structured_output",
				Arguments: `{"name":"Bob","age":25}`,
			},
		},
	})
	model := newMockModel(mp)

	messages := []Message{
		SystemMessage("You are helpful."),
		UserMessage("Tell me about Bob"),
	}

	result, err := GenerateWith[testPerson](context.Background(), model, messages)
	if err != nil {
		t.Fatalf("unexpected error: %v", err)
	}
	if result.Name != "Bob" {
		t.Errorf("expected name 'Bob', got %q", result.Name)
	}
	if result.Age != 25 {
		t.Errorf("expected age 25, got %d", result.Age)
	}

	// Verify messages were passed through
	req := mp.lastRequest()
	if len(req.Messages) != 2 {
		t.Fatalf("expected 2 messages, got %d", len(req.Messages))
	}
	if req.Messages[0].Role != "system" {
		t.Errorf("expected first message role 'system', got %q", req.Messages[0].Role)
	}
}

func TestGenerate_NoToolCall(t *testing.T) {
	mp := newMockProvider(provider.Response{
		Text: "I can't use tools right now.",
	})
	model := newMockModel(mp)

	_, err := Generate[testPerson](context.Background(), model, "Tell me about someone")
	if err == nil {
		t.Fatal("expected error, got nil")
	}
	if !errors.Is(err, ErrNoStructuredOutput) {
		t.Errorf("expected ErrNoStructuredOutput, got %v", err)
	}
}

func TestGenerate_InvalidJSON(t *testing.T) {
	mp := newMockProvider(provider.Response{
		ToolCalls: []provider.ToolCall{
			{
				ID:        "call_1",
				Name:      "structured_output",
				Arguments: `{not valid json}`,
			},
		},
	})
	model := newMockModel(mp)

	_, err := Generate[testPerson](context.Background(), model, "Tell me about someone")
	if err == nil {
		t.Fatal("expected error, got nil")
	}
	if errors.Is(err, ErrNoStructuredOutput) {
		t.Error("expected parse error, not ErrNoStructuredOutput")
	}
}

type testAddress struct {
	Street string `json:"street" description:"Street address"`
	City   string `json:"city" description:"City name"`
}

type testPersonWithAddress struct {
	Name    string      `json:"name" description:"The person's name"`
	Age     int         `json:"age" description:"The person's age"`
	Address testAddress `json:"address" description:"The person's address"`
}

func TestGenerate_NestedStruct(t *testing.T) {
	mp := newMockProvider(provider.Response{
		ToolCalls: []provider.ToolCall{
			{
				ID:        "call_1",
				Name:      "structured_output",
				Arguments: `{"name":"Carol","age":40,"address":{"street":"123 Main St","city":"Springfield"}}`,
			},
		},
	})
	model := newMockModel(mp)

	result, err := Generate[testPersonWithAddress](context.Background(), model, "Tell me about Carol")
	if err != nil {
		t.Fatalf("unexpected error: %v", err)
	}
	if result.Name != "Carol" {
		t.Errorf("expected name 'Carol', got %q", result.Name)
	}
	if result.Address.Street != "123 Main St" {
		t.Errorf("expected street '123 Main St', got %q", result.Address.Street)
	}
	if result.Address.City != "Springfield" {
		t.Errorf("expected city 'Springfield', got %q", result.Address.City)
	}
}

func TestGenerate_WithOptions(t *testing.T) {
	mp := newMockProvider(provider.Response{
		ToolCalls: []provider.ToolCall{
			{
				ID:        "call_1",
				Name:      "structured_output",
				Arguments: `{"name":"Dave","age":35}`,
			},
		},
	})
	model := newMockModel(mp)

	_, err := Generate[testPerson](context.Background(), model, "Tell me about Dave",
		WithTemperature(0.5),
		WithMaxTokens(200),
	)
	if err != nil {
		t.Fatalf("unexpected error: %v", err)
	}

	req := mp.lastRequest()
	if req.Temperature == nil || *req.Temperature != 0.5 {
		t.Errorf("expected temperature 0.5, got %v", req.Temperature)
	}
	if req.MaxTokens == nil || *req.MaxTokens != 200 {
		t.Errorf("expected maxTokens 200, got %v", req.MaxTokens)
	}
}

func TestGenerate_WithMiddleware(t *testing.T) {
	var middlewareCalled bool
	mw := func(next CompletionFunc) CompletionFunc {
		return func(ctx context.Context, model string, messages []Message, cfg *requestConfig) (Response, error) {
			middlewareCalled = true
			return next(ctx, model, messages, cfg)
		}
	}

	mp := newMockProvider(provider.Response{
		ToolCalls: []provider.ToolCall{
			{
				ID:        "call_1",
				Name:      "structured_output",
				Arguments: `{"name":"Eve","age":28}`,
			},
		},
	})
	model := newMockModel(mp).WithMiddleware(mw)

	result, err := Generate[testPerson](context.Background(), model, "Tell me about Eve")
	if err != nil {
		t.Fatalf("unexpected error: %v", err)
	}
	if !middlewareCalled {
		t.Error("middleware was not called")
	}
	if result.Name != "Eve" {
		t.Errorf("expected name 'Eve', got %q", result.Name)
	}
}

func TestGenerate_WrongToolName(t *testing.T) {
	mp := newMockProvider(provider.Response{
		ToolCalls: []provider.ToolCall{
			{
				ID:        "call_1",
				Name:      "some_other_tool",
				Arguments: `{"name":"Frank","age":50}`,
			},
		},
	})
	model := newMockModel(mp)

	_, err := Generate[testPerson](context.Background(), model, "Tell me about Frank")
	if err == nil {
		t.Fatal("expected error, got nil")
	}
	if !errors.Is(err, ErrNoStructuredOutput) {
		t.Errorf("expected ErrNoStructuredOutput, got %v", err)
	}
}