package service

import (
	"context"
	"errors"
	"fmt"
	"net/url"
	"os"
	"strings"
	"sync"
	"testing"
	"time"

	"github.com/gochat/gochat/internal/model"
	"github.com/stretchr/testify/assert"
	"github.com/stretchr/testify/require"
	"gorm.io/driver/postgres"
	"gorm.io/gorm"
	"gorm.io/gorm/logger"
)

func TestWidgetConversationRollsBackCaptainBindingOnCreateFailure(t *testing.T) {
	db, svc := setupWidgetServiceTest(t)
	account, inbox := seedWidgetInbox(t, db)
	contact := &model.Contact{AccountID: account.ID, Name: "Atomic visitor"}
	require.NoError(t, db.Create(contact).Error)
	contactInbox := &model.ContactInbox{ContactID: contact.ID, InboxID: inbox.ID, SourceID: "atomic"}
	require.NoError(t, db.Create(contactInbox).Error)
	assistant := &model.CaptainAssistant{AccountID: account.ID, Name: "Atomic", Status: model.AssistantStatusActive}
	require.NoError(t, db.Create(assistant).Error)
	require.NoError(t, db.Create(&model.CaptainInbox{AccountID: account.ID, InboxID: inbox.ID, AssistantID: assistant.ID}).Error)
	require.NoError(t, db.Create(&model.CaptainPreference{AccountID: account.ID, AutoReplyEnabled: true}).Error)
	require.NoError(t, db.Callback().Create().Before("gorm:create").Register("test:fail_conversation_create", func(tx *gorm.DB) {
		if tx.Statement.Table == "conversations" {
			require.ErrorContains(t, tx.AddError(errors.New("conversation create failed")), "conversation create failed")
		}
	}))
	t.Cleanup(func() { _ = db.Callback().Create().Remove("test:fail_conversation_create") })

	_, err := svc.createWidgetConversation(context.Background(), contactInbox, nil, nil)
	require.ErrorContains(t, err, "conversation create failed")
	for _, value := range []any{&model.Conversation{}, &model.AgentBot{}, &model.AgentBotInbox{}} {
		var count int64
		require.NoError(t, db.Model(value).Count(&count).Error)
		assert.Zero(t, count)
	}
}

func TestEnsureCaptainAgentBotBindingConcurrentCallsStayUnique(t *testing.T) {
	if os.Getenv("GOCHAT_TEST_DB") == "sqlite" {
		t.Skip("requires PostgreSQL conflict handling")
	}
	dsn := os.Getenv("GOCHAT_TEST_DB_URL")
	if dsn == "" {
		dsn = "host=localhost port=5432 user=postgres password=postgres dbname=gochat_test sslmode=disable"
	}
	admin, err := gorm.Open(postgres.Open(dsn), &gorm.Config{Logger: logger.Default.LogMode(logger.Silent)})
	require.NoError(t, err)
	schema := fmt.Sprintf("captain_binding_%d", time.Now().UnixNano())
	require.NoError(t, admin.Exec("CREATE SCHEMA "+schema).Error)
	t.Cleanup(func() {
		_ = admin.Exec("DROP SCHEMA " + schema + " CASCADE").Error
		if sqlDB, dbErr := admin.DB(); dbErr == nil {
			_ = sqlDB.Close()
		}
	})
	if strings.HasPrefix(dsn, "postgres://") || strings.HasPrefix(dsn, "postgresql://") {
		dsnURL, parseErr := url.Parse(dsn)
		require.NoError(t, parseErr)
		query := dsnURL.Query()
		query.Set("search_path", schema)
		dsnURL.RawQuery = query.Encode()
		dsn = dsnURL.String()
	} else {
		dsn += " search_path=" + schema
	}
	db, err := gorm.Open(postgres.Open(dsn), &gorm.Config{
		Logger:                                   logger.Default.LogMode(logger.Silent),
		DisableForeignKeyConstraintWhenMigrating: true,
	})
	require.NoError(t, err)
	require.NoError(t, db.AutoMigrate(&model.CaptainAssistant{}, &model.AgentBot{}, &model.AgentBotInbox{}))
	sqlDB, err := db.DB()
	require.NoError(t, err)
	const calls = 8
	sqlDB.SetMaxOpenConns(calls)
	t.Cleanup(func() { _ = sqlDB.Close() })
	assistant := &model.CaptainAssistant{AccountID: 1, Name: "Concurrent", Status: model.AssistantStatusActive}
	require.NoError(t, db.Create(assistant).Error)

	errs := make(chan error, calls)
	ids := make(chan uint, calls)
	ready := make(chan struct{}, calls)
	start := make(chan struct{})
	var wg sync.WaitGroup
	for range calls {
		wg.Add(1)
		go func() {
			defer wg.Done()
			var bot *model.AgentBot
			err := db.Transaction(func(tx *gorm.DB) error {
				ready <- struct{}{}
				<-start
				var bindErr error
				bot, bindErr = ensureCaptainAgentBotBinding(context.Background(), tx, assistant, 42)
				return bindErr
			})
			errs <- err
			if bot != nil {
				ids <- bot.ID
			}
		}()
	}
	for range calls {
		<-ready
	}
	close(start)
	wg.Wait()
	close(errs)
	close(ids)
	for err := range errs {
		require.NoError(t, err)
	}
	var first uint
	for id := range ids {
		if first == 0 {
			first = id
		}
		assert.Equal(t, first, id)
	}
	for _, value := range []any{&model.AgentBot{}, &model.AgentBotInbox{}} {
		var count int64
		require.NoError(t, db.Model(value).Count(&count).Error)
		assert.Equal(t, int64(1), count)
	}
}

func TestDissociateInboxRollsBackCaptainDeleteWhenBindingDeleteFails(t *testing.T) {
	db, _, svc := setupCov7CaptainAssistant(t)
	account := seedCov7Account(t, db)
	inbox := seedCov7Inbox(t, db, account.ID)
	assistant, err := svc.Create(context.Background(), account.ID, &CreateAssistantRequest{Name: "Rollback", Description: "test"})
	require.NoError(t, err)
	_, err = svc.AssociateInbox(context.Background(), assistant.ID, inbox.ID, account.ID)
	require.NoError(t, err)
	require.NoError(t, db.Callback().Delete().Before("gorm:delete").Register("test:fail_binding_delete", func(tx *gorm.DB) {
		if tx.Statement.Table == "agent_bot_inboxes" {
			require.ErrorContains(t, tx.AddError(errors.New("binding delete failed")), "binding delete failed")
		}
	}))
	t.Cleanup(func() { _ = db.Callback().Delete().Remove("test:fail_binding_delete") })

	err = svc.DissociateInbox(context.Background(), account.ID, assistant.ID, inbox.ID)
	require.ErrorContains(t, err, "binding delete failed")
	var captainInboxCount, bindingCount int64
	require.NoError(t, db.Model(&model.CaptainInbox{}).Where("inbox_id = ?", inbox.ID).Count(&captainInboxCount).Error)
	require.NoError(t, db.Model(&model.AgentBotInbox{}).Where("inbox_id = ?", inbox.ID).Count(&bindingCount).Error)
	assert.Equal(t, int64(1), captainInboxCount)
	assert.Equal(t, int64(1), bindingCount)
}