package service

import (
	"context"
	"testing"

	"github.com/stretchr/testify/assert"
	"github.com/stretchr/testify/require"
	"gorm.io/driver/sqlite"
	"gorm.io/gorm"
	"gorm.io/gorm/logger"

	"github.com/gochat/gochat/internal/model"
	"github.com/gochat/gochat/internal/repository"
)

// ========== Test Setup ==========

func setupDraftMessageServiceTestDB(t *testing.T) *gorm.DB {
	t.Helper()

	db, err := gorm.Open(sqlite.Open("file::memory:"), &gorm.Config{
		Logger: logger.Default.LogMode(logger.Silent),
	})
	require.NoError(t, err, "failed to open SQLite test db")

	require.NoError(t, db.AutoMigrate(
		&model.Account{},
		&model.User{},
		&model.Inbox{},
		&model.Contact{},
		&model.ContactInbox{},
		&model.Conversation{},
		&model.DraftMessage{},
	), "failed to auto-migrate")

	t.Cleanup(func() {
		sqlDB, _ := db.DB()
		sqlDB.Close()
	})

	return db
}

func createDraftTestAccount(t *testing.T, db *gorm.DB) *model.Account {
	t.Helper()
	account := &model.Account{Name: "DraftTestOrg", Locale: "en", Active: true}
	require.NoError(t, db.Create(account).Error)
	return account
}

func createDraftTestUser(t *testing.T, db *gorm.DB) *model.User {
	t.Helper()
	user := &model.User{Name: "DraftAgent", Email: "draftagent@test.com", Provider: "email", Role: "agent"}
	require.NoError(t, db.Create(user).Error)
	return user
}

func createDraftTestInbox(t *testing.T, db *gorm.DB, accountID uint) *model.Inbox {
	t.Helper()
	inbox := &model.Inbox{AccountID: accountID, Name: "DraftInbox", ChannelType: "web_widget", ChannelID: 1, Enabled: true}
	require.NoError(t, db.Create(inbox).Error)
	return inbox
}

func createDraftTestContact(t *testing.T, db *gorm.DB, accountID uint) *model.Contact {
	t.Helper()
	contact := &model.Contact{AccountID: accountID, Name: "DraftContact", Email: "draftcontact@test.com"}
	require.NoError(t, db.Create(contact).Error)
	return contact
}

func createDraftTestConversation(t *testing.T, db *gorm.DB, accountID, inboxID, contactID uint) *model.Conversation {
	t.Helper()
	conversation := &model.Conversation{
		AccountID:   accountID,
		InboxID:     inboxID,
		ContactID:   contactID,
		ChannelType: "web_widget",
		Channel:     "web_widget",
		Status:      "open",
	}
	require.NoError(t, db.Create(conversation).Error)
	return conversation
}

func setupDraftMessageService(t *testing.T) (*DraftMessageService, *gorm.DB) {
	t.Helper()
	db := setupDraftMessageServiceTestDB(t)
	repo := repository.NewDraftMessageRepo(db)
	conversationRepo := repository.NewConversationRepo(db)
	svc := NewDraftMessageService(repo, conversationRepo)
	return svc, db
}

// ========== Create Draft Tests ==========

func TestDraftMessageService_Create_Success(t *testing.T) {
	svc, db := setupDraftMessageService(t)
	ctx := context.Background()

	account := createDraftTestAccount(t, db)
	user := createDraftTestUser(t, db)
	inbox := createDraftTestInbox(t, db, account.ID)
	contact := createDraftTestContact(t, db, account.ID)
	conversation := createDraftTestConversation(t, db, account.ID, inbox.ID, contact.ID)

	draft, err := svc.Create(ctx, account.ID, conversation.ID, user.ID, "Hello, this is a draft message")
	require.NoError(t, err)
	assert.NotNil(t, draft)
	assert.Equal(t, conversation.ID, draft.ConversationID)
	assert.Equal(t, user.ID, draft.UserID)
	assert.Equal(t, "Hello, this is a draft message", draft.Content)
}

func TestDraftMessageService_Create_ConversationNotFound(t *testing.T) {
	svc, db := setupDraftMessageService(t)
	ctx := context.Background()

	account := createDraftTestAccount(t, db)
	user := createDraftTestUser(t, db)

	draft, err := svc.Create(ctx, account.ID, 99999, user.ID, "draft content")
	assert.Error(t, err)
	assert.Nil(t, draft)
}

func TestDraftMessageService_Create_AccountMismatch(t *testing.T) {
	svc, db := setupDraftMessageService(t)
	ctx := context.Background()

	account := createDraftTestAccount(t, db)
	user := createDraftTestUser(t, db)
	inbox := createDraftTestInbox(t, db, account.ID)
	contact := createDraftTestContact(t, db, account.ID)
	conversation := createDraftTestConversation(t, db, account.ID, inbox.ID, contact.ID)

	// Use a wrong accountID
	wrongAccountID := uint(99999)
	draft, err := svc.Create(ctx, wrongAccountID, conversation.ID, user.ID, "draft content")
	assert.Error(t, err)
	assert.Nil(t, draft)
}

// ========== Get Draft Tests ==========

func TestDraftMessageService_Get_Success(t *testing.T) {
	svc, db := setupDraftMessageService(t)
	ctx := context.Background()

	account := createDraftTestAccount(t, db)
	user := createDraftTestUser(t, db)
	inbox := createDraftTestInbox(t, db, account.ID)
	contact := createDraftTestContact(t, db, account.ID)
	conversation := createDraftTestConversation(t, db, account.ID, inbox.ID, contact.ID)

	draft, err := svc.Create(ctx, account.ID, conversation.ID, user.ID, "draft content")
	require.NoError(t, err)

	fetched, err := svc.Get(ctx, draft.ID)
	require.NoError(t, err)
	assert.Equal(t, draft.ID, fetched.ID)
	assert.Equal(t, draft.Content, fetched.Content)
}

func TestDraftMessageService_Get_NotFound(t *testing.T) {
	svc, _ := setupDraftMessageService(t)
	ctx := context.Background()

	draft, err := svc.Get(ctx, 99999)
	assert.Error(t, err)
	assert.Nil(t, draft)
}

// ========== List Drafts Tests ==========

func TestDraftMessageService_List_Success(t *testing.T) {
	svc, db := setupDraftMessageService(t)
	ctx := context.Background()

	account := createDraftTestAccount(t, db)
	user := createDraftTestUser(t, db)
	inbox := createDraftTestInbox(t, db, account.ID)
	contact := createDraftTestContact(t, db, account.ID)
	conversation := createDraftTestConversation(t, db, account.ID, inbox.ID, contact.ID)

	// Create two drafts
	_, err := svc.Create(ctx, account.ID, conversation.ID, user.ID, "draft 1")
	require.NoError(t, err)
	_, err = svc.Create(ctx, account.ID, conversation.ID, user.ID, "draft 2")
	require.NoError(t, err)

	// List drafts filtered by user (userID > 0)
	drafts, err := svc.List(ctx, account.ID, conversation.ID, user.ID)
	require.NoError(t, err)
	assert.Len(t, drafts, 2)
}

func TestDraftMessageService_List_AllUsers(t *testing.T) {
	svc, db := setupDraftMessageService(t)
	ctx := context.Background()

	account := createDraftTestAccount(t, db)
	user1 := createDraftTestUser(t, db)
	// Create a second user
	user2 := &model.User{Name: "DraftAgent2", Email: "draftagent2@test.com", Provider: "email", Role: "agent"}
	require.NoError(t, db.Create(user2).Error)
	inbox := createDraftTestInbox(t, db, account.ID)
	contact := createDraftTestContact(t, db, account.ID)
	conversation := createDraftTestConversation(t, db, account.ID, inbox.ID, contact.ID)

	// Create drafts for two different users
	_, err := svc.Create(ctx, account.ID, conversation.ID, user1.ID, "draft by user1")
	require.NoError(t, err)
	_, err = svc.Create(ctx, account.ID, conversation.ID, user2.ID, "draft by user2")
	require.NoError(t, err)

	// List all drafts (userID = 0 means no filter)
	drafts, err := svc.List(ctx, account.ID, conversation.ID, 0)
	require.NoError(t, err)
	assert.Len(t, drafts, 2)
}

func TestDraftMessageService_List_Empty(t *testing.T) {
	svc, db := setupDraftMessageService(t)
	ctx := context.Background()

	account := createDraftTestAccount(t, db)
	inbox := createDraftTestInbox(t, db, account.ID)
	contact := createDraftTestContact(t, db, account.ID)
	conversation := createDraftTestConversation(t, db, account.ID, inbox.ID, contact.ID)

	drafts, err := svc.List(ctx, account.ID, conversation.ID, 0)
	require.NoError(t, err)
	assert.Empty(t, drafts)
}

func TestDraftMessageService_List_ConversationNotFound(t *testing.T) {
	svc, db := setupDraftMessageService(t)
	ctx := context.Background()

	account := createDraftTestAccount(t, db)

	drafts, err := svc.List(ctx, account.ID, 99999, 0)
	assert.Error(t, err)
	assert.Nil(t, drafts)
}

func TestDraftMessageService_List_AccountMismatch(t *testing.T) {
	svc, db := setupDraftMessageService(t)
	ctx := context.Background()

	account := createDraftTestAccount(t, db)
	inbox := createDraftTestInbox(t, db, account.ID)
	contact := createDraftTestContact(t, db, account.ID)
	conversation := createDraftTestConversation(t, db, account.ID, inbox.ID, contact.ID)

	drafts, err := svc.List(ctx, 99999, conversation.ID, 0)
	assert.Error(t, err)
	assert.Nil(t, drafts)
}

// ========== Update Draft Tests ==========

func TestDraftMessageService_Update_Success(t *testing.T) {
	svc, db := setupDraftMessageService(t)
	ctx := context.Background()

	account := createDraftTestAccount(t, db)
	user := createDraftTestUser(t, db)
	inbox := createDraftTestInbox(t, db, account.ID)
	contact := createDraftTestContact(t, db, account.ID)
	conversation := createDraftTestConversation(t, db, account.ID, inbox.ID, contact.ID)

	draft, err := svc.Create(ctx, account.ID, conversation.ID, user.ID, "original content")
	require.NoError(t, err)

	updated, err := svc.Update(ctx, draft.ID, "updated content")
	require.NoError(t, err)
	assert.Equal(t, "updated content", updated.Content)
}

func TestDraftMessageService_Update_NotFound(t *testing.T) {
	svc, _ := setupDraftMessageService(t)
	ctx := context.Background()

	updated, err := svc.Update(ctx, 99999, "updated content")
	assert.Error(t, err)
	assert.Nil(t, updated)
}

// ========== Delete Draft Tests ==========

func TestDraftMessageService_Delete_Success(t *testing.T) {
	svc, db := setupDraftMessageService(t)
	ctx := context.Background()

	account := createDraftTestAccount(t, db)
	user := createDraftTestUser(t, db)
	inbox := createDraftTestInbox(t, db, account.ID)
	contact := createDraftTestContact(t, db, account.ID)
	conversation := createDraftTestConversation(t, db, account.ID, inbox.ID, contact.ID)

	draft, err := svc.Create(ctx, account.ID, conversation.ID, user.ID, "draft to delete")
	require.NoError(t, err)

	err = svc.Delete(ctx, draft.ID)
	require.NoError(t, err)

	// Verify draft is deleted
	_, err = svc.Get(ctx, draft.ID)
	assert.Error(t, err)
}

func TestDraftMessageService_Delete_NotFound(t *testing.T) {
	svc, _ := setupDraftMessageService(t)
	ctx := context.Background()

	err := svc.Delete(ctx, 99999)
	assert.Error(t, err)
}