package autoassignment

import (
	"context"
	"testing"
	"time"

	"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"
)

func setupCapacityAssignmentDB(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)
	require.NoError(t, db.AutoMigrate(
		&model.Account{},
		&model.User{},
		&model.AccountUser{},
		&model.Inbox{},
		&model.InboxMember{},
		&model.Contact{},
		&model.Conversation{},
		&model.AssignmentPolicy{},
		&model.InboxAssignmentPolicy{},
		&model.AgentCapacityPolicy{},
		&model.InboxCapacityLimit{},
		&model.Tag{},
		&model.ConversationLabel{},
	))
	return db
}

func TestAssignmentService_SkipsAgentsAtInboxCapacity(t *testing.T) {
	_, rdb := setupTestRedis(t)
	db := setupCapacityAssignmentDB(t)
	svc := NewAssignmentService(db, rdb)
	ctx := context.Background()

	account := &model.Account{Name: "Capacity Account", FeatureFlags: `{"advanced_assignment":true}`}
	require.NoError(t, db.Create(account).Error)
	inbox := &model.Inbox{AccountID: account.ID, Name: "Capacity Inbox", ChannelType: string(model.InboxChannelTypeWebWidget), EnableAutoAssignment: true}
	require.NoError(t, db.Create(inbox).Error)
	contact := &model.Contact{AccountID: account.ID, Name: "Capacity Contact"}
	require.NoError(t, db.Create(contact).Error)

	agentAtCapacity := createCapacityUser(t, db, account.ID, "full@test.com")
	agentWithCapacity := createCapacityUser(t, db, account.ID, "available@test.com")
	require.NoError(t, db.Create(&model.InboxMember{InboxID: inbox.ID, UserID: agentAtCapacity.ID}).Error)
	require.NoError(t, db.Create(&model.InboxMember{InboxID: inbox.ID, UserID: agentWithCapacity.ID}).Error)

	policy := &model.AgentCapacityPolicy{AccountID: account.ID, Name: "Capacity", AssignmentLogic: "round_robin", ExclusionRules: []byte(`{}`)}
	require.NoError(t, db.Create(policy).Error)
	require.NoError(t, db.Model(&model.AccountUser{}).
		Where("account_id = ? AND user_id = ?", account.ID, agentAtCapacity.ID).
		Update("agent_capacity_policy_id", policy.ID).Error)
	require.NoError(t, db.Create(&model.InboxCapacityLimit{AgentCapacityPolicyID: policy.ID, InboxID: inbox.ID, ConversationLimit: 1}).Error)

	now := time.Now().Unix()
	existing := &model.Conversation{AccountID: account.ID, InboxID: inbox.ID, ContactID: contact.ID, AssigneeID: &agentAtCapacity.ID, Status: string(model.ConversationStatusOpen), ChannelType: "web_widget", Channel: "web_widget", LastActivityAt: &now}
	unassigned := &model.Conversation{AccountID: account.ID, InboxID: inbox.ID, ContactID: contact.ID, Status: string(model.ConversationStatusOpen), ChannelType: "web_widget", Channel: "web_widget", LastActivityAt: &now}
	require.NoError(t, db.Create(existing).Error)
	require.NoError(t, db.Create(unassigned).Error)

	agentID, err := svc.AssignConversation(ctx, unassigned.ID, inbox.ID, account.ID)
	require.NoError(t, err)
	assert.Equal(t, agentWithCapacity.ID, agentID)
}

func TestAssignmentServiceIgnoresCapacityWhenAdvancedAssignmentIsDisabled(t *testing.T) {
	_, rdb := setupTestRedis(t)
	db := setupCapacityAssignmentDB(t)
	account := &model.Account{Name: "Default Assignment"}
	require.NoError(t, db.Create(account).Error)
	inbox := &model.Inbox{AccountID: account.ID, Name: "Inbox", ChannelType: string(model.InboxChannelTypeWebWidget), EnableAutoAssignment: true}
	require.NoError(t, db.Create(inbox).Error)
	agent := createCapacityUser(t, db, account.ID, "default@test.com")
	require.NoError(t, db.Create(&model.InboxMember{InboxID: inbox.ID, UserID: agent.ID}).Error)
	policy := &model.AgentCapacityPolicy{AccountID: account.ID, Name: "Excluded", ExclusionRules: []byte(`{"exclude_older_than_hours":1}`)}
	require.NoError(t, db.Create(policy).Error)
	require.NoError(t, db.Model(&model.AccountUser{}).Where("account_id = ? AND user_id = ?", account.ID, agent.ID).Update("agent_capacity_policy_id", policy.ID).Error)
	require.NoError(t, db.Create(&model.InboxCapacityLimit{AgentCapacityPolicyID: policy.ID, InboxID: inbox.ID, ConversationLimit: 0}).Error)
	contact := &model.Contact{AccountID: account.ID, Name: "Contact"}
	require.NoError(t, db.Create(contact).Error)
	old := time.Now().Add(-2 * time.Hour).Unix()
	conversation := &model.Conversation{AccountID: account.ID, InboxID: inbox.ID, ContactID: contact.ID, Status: string(model.ConversationStatusOpen), LastActivityAt: &old}
	require.NoError(t, db.Create(conversation).Error)

	assigned, err := NewAssignmentService(db, rdb).AssignConversation(context.Background(), conversation.ID, inbox.ID, account.ID)
	require.NoError(t, err)
	require.Equal(t, agent.ID, assigned)
}

func TestAssignmentServiceAppliesCapacityPolicyExclusions(t *testing.T) {
	_, rdb := setupTestRedis(t)
	db := setupCapacityAssignmentDB(t)
	account := &model.Account{Name: "Exclusions", FeatureFlags: `{"advanced_assignment":true}`}
	require.NoError(t, db.Create(account).Error)
	inbox := &model.Inbox{AccountID: account.ID, Name: "Inbox", ChannelType: string(model.InboxChannelTypeWebWidget), EnableAutoAssignment: true}
	require.NoError(t, db.Create(inbox).Error)
	agent := createCapacityUser(t, db, account.ID, "exclusions@test.com")
	require.NoError(t, db.Create(&model.InboxMember{InboxID: inbox.ID, UserID: agent.ID}).Error)
	capacityPolicy := &model.AgentCapacityPolicy{
		AccountID:      account.ID,
		Name:           "Exclude stale spam",
		ExclusionRules: []byte(`{"excluded_labels":["spam"],"exclude_older_than_hours":24}`),
	}
	require.NoError(t, db.Create(capacityPolicy).Error)
	require.NoError(t, db.Model(&model.AccountUser{}).Where("account_id = ? AND user_id = ?", account.ID, agent.ID).Update("agent_capacity_policy_id", capacityPolicy.ID).Error)
	require.NoError(t, db.Create(&model.InboxCapacityLimit{AgentCapacityPolicyID: capacityPolicy.ID, InboxID: inbox.ID, ConversationLimit: 10}).Error)
	contact := &model.Contact{AccountID: account.ID, Name: "Contact"}
	require.NoError(t, db.Create(contact).Error)

	now := time.Now().Unix()
	old := time.Now().Add(-25 * time.Hour).Unix()
	recent := &model.Conversation{AccountID: account.ID, InboxID: inbox.ID, ContactID: contact.ID, Status: string(model.ConversationStatusOpen), LastActivityAt: &now}
	labeled := &model.Conversation{AccountID: account.ID, InboxID: inbox.ID, ContactID: contact.ID, Status: string(model.ConversationStatusOpen), LastActivityAt: &now}
	stale := &model.Conversation{AccountID: account.ID, InboxID: inbox.ID, ContactID: contact.ID, Status: string(model.ConversationStatusOpen), LastActivityAt: &old}
	unknownAge := &model.Conversation{AccountID: account.ID, InboxID: inbox.ID, ContactID: contact.ID, Status: string(model.ConversationStatusOpen)}
	require.NoError(t, db.Create([]*model.Conversation{recent, labeled, stale, unknownAge}).Error)
	tag := &model.Tag{AccountID: account.ID, Name: "spam"}
	require.NoError(t, db.Create(tag).Error)
	require.NoError(t, db.Create(&model.ConversationLabel{AccountID: account.ID, ConversationID: labeled.ID, TagID: tag.ID}).Error)

	assigned, err := NewAssignmentService(db, rdb).AssignUnassignedConversations(context.Background(), inbox.ID, account.ID)
	require.NoError(t, err)
	require.Equal(t, []uint{recent.ID}, assigned)
	for _, excluded := range []*model.Conversation{labeled, stale, unknownAge} {
		require.NoError(t, db.First(excluded, excluded.ID).Error)
		require.Nil(t, excluded.AssigneeID)
	}
}

func TestAssignmentServiceAppliesEachAgentsCapacityPolicyExclusions(t *testing.T) {
	_, rdb := setupTestRedis(t)
	db := setupCapacityAssignmentDB(t)
	account := &model.Account{Name: "Per-agent exclusions", FeatureFlags: `{"advanced_assignment":true}`}
	require.NoError(t, db.Create(account).Error)
	inbox := &model.Inbox{AccountID: account.ID, Name: "Inbox", ChannelType: string(model.InboxChannelTypeWebWidget), EnableAutoAssignment: true}
	require.NoError(t, db.Create(inbox).Error)
	spamAgent := createCapacityUser(t, db, account.ID, "spam-policy@test.com")
	vipAgent := createCapacityUser(t, db, account.ID, "vip-policy@test.com")
	require.NoError(t, db.Create([]*model.InboxMember{{InboxID: inbox.ID, UserID: spamAgent.ID}, {InboxID: inbox.ID, UserID: vipAgent.ID}}).Error)

	spamPolicy := &model.AgentCapacityPolicy{AccountID: account.ID, Name: "Exclude spam", ExclusionRules: []byte(`{"excluded_labels":["spam"]}`)}
	vipPolicy := &model.AgentCapacityPolicy{AccountID: account.ID, Name: "Exclude vip", ExclusionRules: []byte(`{"excluded_labels":["vip"]}`)}
	require.NoError(t, db.Create(spamPolicy).Error)
	require.NoError(t, db.Create(vipPolicy).Error)
	require.NoError(t, db.Model(&model.AccountUser{}).Where("account_id = ? AND user_id = ?", account.ID, spamAgent.ID).Update("agent_capacity_policy_id", spamPolicy.ID).Error)
	require.NoError(t, db.Model(&model.AccountUser{}).Where("account_id = ? AND user_id = ?", account.ID, vipAgent.ID).Update("agent_capacity_policy_id", vipPolicy.ID).Error)
	require.NoError(t, db.Create([]*model.InboxCapacityLimit{
		{AgentCapacityPolicyID: spamPolicy.ID, InboxID: inbox.ID, ConversationLimit: 10},
		{AgentCapacityPolicyID: vipPolicy.ID, InboxID: inbox.ID, ConversationLimit: 10},
	}).Error)

	contact := &model.Contact{AccountID: account.ID, Name: "Contact"}
	require.NoError(t, db.Create(contact).Error)
	now := time.Now().Unix()
	spam := &model.Conversation{AccountID: account.ID, InboxID: inbox.ID, ContactID: contact.ID, Status: string(model.ConversationStatusOpen), LastActivityAt: &now}
	vip := &model.Conversation{AccountID: account.ID, InboxID: inbox.ID, ContactID: contact.ID, Status: string(model.ConversationStatusOpen), LastActivityAt: &now}
	require.NoError(t, db.Create([]*model.Conversation{spam, vip}).Error)
	spamTag := &model.Tag{AccountID: account.ID, Name: "spam"}
	vipTag := &model.Tag{AccountID: account.ID, Name: "vip"}
	require.NoError(t, db.Create([]*model.Tag{spamTag, vipTag}).Error)
	require.NoError(t, db.Create([]*model.ConversationLabel{
		{AccountID: account.ID, ConversationID: spam.ID, TagID: spamTag.ID},
		{AccountID: account.ID, ConversationID: vip.ID, TagID: vipTag.ID},
	}).Error)

	assigned, err := NewAssignmentService(db, rdb).AssignUnassignedConversations(context.Background(), inbox.ID, account.ID)
	require.NoError(t, err)
	require.Equal(t, []uint{spam.ID, vip.ID}, assigned)
	require.NoError(t, db.First(spam, spam.ID).Error)
	require.NoError(t, db.First(vip, vip.ID).Error)
	require.Equal(t, vipAgent.ID, *spam.AssigneeID)
	require.Equal(t, spamAgent.ID, *vip.AssigneeID)
}

func TestAssignmentEligibilityRejectsSoftDeletedUserAndAccountUser(t *testing.T) {
	for _, deleted := range []string{"user", "account user"} {
		t.Run(deleted, func(t *testing.T) {
			db := setupCapacityAssignmentDB(t)
			account := &model.Account{Name: deleted}
			require.NoError(t, db.Create(account).Error)
			inbox := &model.Inbox{AccountID: account.ID, Name: "Inbox", ChannelType: string(model.InboxChannelTypeWebWidget), EnableAutoAssignment: true}
			require.NoError(t, db.Create(inbox).Error)
			agent := createCapacityUser(t, db, account.ID, deleted+"@test.com")
			require.NoError(t, db.Create(&model.InboxMember{InboxID: inbox.ID, UserID: agent.ID}).Error)
			contact := &model.Contact{AccountID: account.ID, Name: "Contact"}
			require.NoError(t, db.Create(contact).Error)
			conversation := &model.Conversation{AccountID: account.ID, InboxID: inbox.ID, ContactID: contact.ID, Status: string(model.ConversationStatusOpen)}
			require.NoError(t, db.Create(conversation).Error)

			if deleted == "user" {
				require.NoError(t, db.Delete(agent).Error)
			} else {
				require.NoError(t, db.Where("account_id = ? AND user_id = ?", account.ID, agent.ID).Delete(&model.AccountUser{}).Error)
			}

			agents, err := NewAssignmentService(db, nil).getEligibleAgents(context.Background(), inbox.ID, account.ID, nil, false)
			require.NoError(t, err)
			require.Empty(t, agents)
			assigned, err := repository.AutoAssignConversation(context.Background(), db, account.ID, inbox.ID, conversation.ID, agent.ID)
			require.NoError(t, err)
			require.False(t, assigned)
		})
	}
}

func TestLongestWaitingSortsUnknownActivityLast(t *testing.T) {
	testLongestWaitingSortsUnknownActivityLast(t, setupCapacityAssignmentDB(t))
}

func testLongestWaitingSortsUnknownActivityLast(t *testing.T, db *gorm.DB) {
	t.Helper()
	account := &model.Account{Name: "Longest waiting"}
	require.NoError(t, db.Create(account).Error)
	inbox := &model.Inbox{AccountID: account.ID, Name: "Inbox", ChannelType: string(model.InboxChannelTypeWebWidget)}
	require.NoError(t, db.Create(inbox).Error)
	contact := &model.Contact{AccountID: account.ID, Name: "Contact"}
	require.NoError(t, db.Create(contact).Error)
	olderActivity := time.Now().Add(-2 * time.Hour).Unix()
	newerActivity := time.Now().Add(-time.Hour).Unix()
	unknown := &model.Conversation{AccountID: account.ID, InboxID: inbox.ID, ContactID: contact.ID, Status: string(model.ConversationStatusOpen)}
	newer := &model.Conversation{AccountID: account.ID, InboxID: inbox.ID, ContactID: contact.ID, Status: string(model.ConversationStatusOpen), LastActivityAt: &newerActivity}
	older := &model.Conversation{AccountID: account.ID, InboxID: inbox.ID, ContactID: contact.ID, Status: string(model.ConversationStatusOpen), LastActivityAt: &olderActivity}
	require.NoError(t, db.Create([]*model.Conversation{unknown, newer, older}).Error)

	conversations, err := NewAssignmentService(db, nil).findUnassignedConversations(
		context.Background(), inbox.ID, account.ID, &model.AssignmentPolicy{ConversationPriority: 1},
	)
	require.NoError(t, err)
	require.Equal(t, []uint{older.ID, newer.ID, unknown.ID}, []uint{conversations[0].ID, conversations[1].ID, conversations[2].ID})
}

func createCapacityUser(t *testing.T, db *gorm.DB, accountID uint, email string) *model.User {
	t.Helper()
	user := &model.User{AccountID: accountID, Name: email, Email: email, Password: "hashed", Active: true, Available: true}
	require.NoError(t, db.Create(user).Error)
	require.NoError(t, db.Create(&model.AccountUser{AccountID: accountID, UserID: user.ID, Role: "agent", Availability: "online"}).Error)
	return user
}