package service

import (
	"context"
	"encoding/json"
	"errors"
	"fmt"
	"testing"
	"time"

	"github.com/gochat/gochat/internal/model"
	"github.com/gochat/gochat/internal/repository"
	"github.com/gochat/gochat/internal/worker"
	"github.com/stretchr/testify/assert"
	"github.com/stretchr/testify/require"
	"gorm.io/driver/sqlite"
	"gorm.io/gorm"
)

func setupCopilotResponseWorkerTest(t *testing.T) (*gorm.DB, *CopilotService, *model.Account, *model.User, *model.CaptainAssistant) {
	t.Helper()
	dbName := fmt.Sprintf("file:%s?mode=memory&cache=private", t.Name())
	db, err := gorm.Open(sqlite.Open(dbName), &gorm.Config{})
	require.NoError(t, err)
	require.NoError(t, db.AutoMigrate(&model.Account{}, &model.User{}, &model.CaptainAssistant{}, &model.CopilotThread{}, &model.CopilotMessage{}, &model.CopilotSuggestionMessage{}, &model.BackgroundJob{}))
	t.Cleanup(func() {
		sqlDB, _ := db.DB()
		sqlDB.Close()
	})
	account := &model.Account{Name: "Copilot Org", Active: true}
	require.NoError(t, db.Create(account).Error)
	user := &model.User{AccountID: account.ID, Name: "Agent", Email: "agent@example.com", Password: "secret", Active: true}
	require.NoError(t, db.Create(user).Error)
	assistant := &model.CaptainAssistant{AccountID: account.ID, Name: "Helper", Config: json.RawMessage(`{}`), Status: model.AssistantStatusActive}
	require.NoError(t, db.Create(assistant).Error)
	svc := NewCopilotService(repository.NewCopilotThreadRepo(db), repository.NewCopilotMessageRepo(db), repository.NewCopilotSuggestionRepo(db), nil, repository.NewCaptainAssistantRepo(db))
	return db, svc, account, user, assistant
}

func TestCopilotResponseJobQueuesAndPersistsAssistantReply(t *testing.T) {
	db, svc, account, user, assistant := setupCopilotResponseWorkerTest(t)
	svc.SetResponseBackend(&fakeCopilotResponseBackend{messages: []CopilotGeneratedMessage{{MessageType: model.CopilotMessageTypeAssistant, Message: map[string]any{"content": "Here is the answer"}}}})
	wp := worker.NewWorkerPool(db)
	svc.SetWorkerPool(wp)

	thread, err := svc.CreateThread(context.Background(), account.ID, user.ID, &CreateThreadRequest{Message: "Need help", AssistantID: assistant.ID, ConversationID: 123})
	require.NoError(t, err)
	require.NotNil(t, thread)

	var count int64
	require.NoError(t, db.Model(&model.CopilotMessage{}).Where("copilot_thread_id = ?", thread.ID).Count(&count).Error)
	assert.Equal(t, int64(1), count)
	require.NoError(t, db.Model(&model.BackgroundJob{}).Where("job_type = ? AND status = ?", TaskTypeCaptainCopilotResponse, model.BackgroundJobStatusQueued).Count(&count).Error)
	assert.Equal(t, int64(1), count)

	processed, err := wp.ProcessOne(context.Background())
	require.NoError(t, err)
	assert.True(t, processed)

	var messages []model.CopilotMessage
	require.NoError(t, db.Where("copilot_thread_id = ?", thread.ID).Order("id ASC").Find(&messages).Error)
	require.Len(t, messages, 2)
	assert.Equal(t, model.CopilotMessageTypeUser, messages[0].MessageType)
	assert.Equal(t, model.CopilotMessageTypeAssistant, messages[1].MessageType)
	assert.Equal(t, "Here is the answer", messages[1].GetMessageContent())
}

func TestCopilotResponseJobUsesDisabledFallbackWithoutProvider(t *testing.T) {
	db, svc, account, user, assistant := setupCopilotResponseWorkerTest(t)
	wp := worker.NewWorkerPool(db)
	svc.SetWorkerPool(wp)

	thread, err := svc.CreateThread(context.Background(), account.ID, user.ID, &CreateThreadRequest{Message: "Need help", AssistantID: assistant.ID})
	require.NoError(t, err)
	processed, err := wp.ProcessOne(context.Background())
	require.NoError(t, err)
	assert.True(t, processed)

	var assistantMsg model.CopilotMessage
	require.NoError(t, db.Where("copilot_thread_id = ? AND message_type = ?", thread.ID, model.CopilotMessageTypeAssistant).First(&assistantMsg).Error)
	assert.Equal(t, CopilotUnavailableMessage, assistantMsg.GetMessageContent())
}

func TestCopilotResponseJobRetriesBackendFailure(t *testing.T) {
	db, svc, account, user, assistant := setupCopilotResponseWorkerTest(t)
	svc.SetResponseBackend(&fakeCopilotResponseBackend{err: errors.New("backend down")})
	now := time.Date(2026, 6, 6, 4, 0, 0, 0, time.UTC)
	wp := worker.NewWorkerPoolWithOptions(db, worker.WithNow(func() time.Time { return now }), worker.WithBackoff(func(attempt int) time.Duration { return time.Minute }))
	svc.SetWorkerPool(wp)

	_, err := svc.CreateThread(context.Background(), account.ID, user.ID, &CreateThreadRequest{Message: "Need help", AssistantID: assistant.ID})
	require.NoError(t, err)
	processed, err := wp.ProcessOne(context.Background())
	require.Error(t, err)
	assert.True(t, processed)

	var job model.BackgroundJob
	require.NoError(t, db.Where("job_type = ?", TaskTypeCaptainCopilotResponse).First(&job).Error)
	assert.Equal(t, model.BackgroundJobStatusRetrying, job.Status)
	assert.Contains(t, job.LastError, "backend down")
}

type fakeCopilotResponseBackend struct {
	messages []CopilotGeneratedMessage
	err      error
}

func (b *fakeCopilotResponseBackend) GenerateCopilotResponse(ctx context.Context, req CopilotResponseRequest) ([]CopilotGeneratedMessage, error) {
	if b.err != nil {
		return nil, b.err
	}
	return b.messages, nil
}