package llm_test

import (
	"context"
	"encoding/json"
	"testing"

	openai "github.com/sashabaranov/go-openai"

	"qbank/internal/llm"
)

// mockChat implements llm.ChatClient for testing.
type mockChat struct{ body string }

func (m *mockChat) CreateChatCompletion(_ context.Context, _ openai.ChatCompletionRequest) (openai.ChatCompletionResponse, error) {
	return openai.ChatCompletionResponse{
		Choices: []openai.ChatCompletionChoice{
			{Message: openai.ChatCompletionMessage{Content: m.body}},
		},
	}, nil
}

func mockClient(t *testing.T, questions []map[string]any) *llm.Client {
	t.Helper()
	body, err := json.Marshal(map[string]any{"questions": questions})
	if err != nil {
		t.Fatal(err)
	}
	return llm.NewWithClient(&mockChat{body: string(body)}, "test-model")
}

func TestExtractQuestions_HappyPath(t *testing.T) {
	qs, err := mockClient(t, []map[string]any{
		{
			"question": "What is 2+2?",
			"answers": []map[string]any{
				{"text": "3", "correct": false},
				{"text": "4", "correct": true},
				{"text": "5", "correct": false},
			},
		},
	}).ExtractQuestions(context.Background(), "text")

	if err != nil {
		t.Fatalf("ExtractQuestions: %v", err)
	}
	if len(qs) != 1 {
		t.Fatalf("want 1 question, got %d", len(qs))
	}
	if qs[0].Question != "What is 2+2?" {
		t.Errorf("wrong question text: %q", qs[0].Question)
	}
	if len(qs[0].Answers) != 3 {
		t.Errorf("want 3 answers, got %d", len(qs[0].Answers))
	}
}

func TestExtractQuestions_DropsInvalid(t *testing.T) {
	qs, err := mockClient(t, []map[string]any{
		{
			"question": "Two correct — should drop",
			"answers": []map[string]any{
				{"text": "A", "correct": true},
				{"text": "B", "correct": true},
			},
		},
		{
			"question": "Zero correct — should drop",
			"answers": []map[string]any{
				{"text": "A", "correct": false},
				{"text": "B", "correct": false},
			},
		},
		{
			"question": "Valid question",
			"answers": []map[string]any{
				{"text": "Wrong", "correct": false},
				{"text": "Right", "correct": true},
			},
		},
	}).ExtractQuestions(context.Background(), "text")

	if err != nil {
		t.Fatalf("ExtractQuestions: %v", err)
	}
	if len(qs) != 1 {
		t.Fatalf("want 1 question after dropping invalid, got %d", len(qs))
	}
	if qs[0].Question != "Valid question" {
		t.Errorf("wrong question kept: %q", qs[0].Question)
	}
}

func TestExtractQuestions_Dedup(t *testing.T) {
	qs, err := mockClient(t, []map[string]any{
		{
			"question": "Duplicate?",
			"answers": []map[string]any{
				{"text": "Yes", "correct": true},
				{"text": "No", "correct": false},
			},
		},
		{
			"question": "Duplicate?",
			"answers": []map[string]any{
				{"text": "Yes", "correct": true},
				{"text": "No", "correct": false},
			},
		},
	}).ExtractQuestions(context.Background(), "text")

	if err != nil {
		t.Fatalf("ExtractQuestions: %v", err)
	}
	if len(qs) != 1 {
		t.Errorf("want 1 unique question after dedup, got %d", len(qs))
	}
}

func TestExtractQuestions_EmptyResponse(t *testing.T) {
	qs, err := mockClient(t, []map[string]any{}).ExtractQuestions(context.Background(), "text")
	if err != nil {
		t.Fatalf("unexpected error: %v", err)
	}
	if len(qs) != 0 {
		t.Errorf("want 0 questions for empty response, got %d", len(qs))
	}
}