package network

import (
	"context"
	"errors"
	"fmt"
	"strings"

	"github.com/flowy-live/llink/internal/utils"
	"github.com/jackc/pgx/v5/pgxpool"
)

var ErrNotFound = errors.New("network not found")
var ErrInvalidName = errors.New("name cannot be empty")
var ErrCapacityExceeded = errors.New("active stream capacity exceeded")

type Service interface {
	// Create creates a network and adds adminEmail as the first member. Returns ErrInvalidName if name is empty.
	Create(ctx context.Context, name, adminEmail string) (*Network, error)
	// GetByID returns ErrNotFound if network doesn't exist.
	GetByID(ctx context.Context, id string) (*Network, error)
	// SetName returns ErrNotFound or ErrInvalidName.
	SetName(ctx context.Context, id, name string) error
	AddMembers(ctx context.Context, networkID string, emails []string) error
	RemoveMember(ctx context.Context, networkID, email string) error
	ListForEmail(ctx context.Context, email string) ([]*Network, error)
	IsMember(ctx context.Context, networkID, email string) (bool, error)

	// SetOpenStreamCapacity sets the max open streams for a network. Returns ErrNotFound.
	SetOpenStreamCapacity(ctx context.Context, networkID string, capacity int) error
	// IncrementOpenStreamCount returns ErrNotFound or ErrCapacityExceeded.
	IncrementOpenStreamCount(ctx context.Context, networkID string) error
	// DecrementOpenStreamCount returns ErrNotFound.
	DecrementOpenStreamCount(ctx context.Context, networkID string) error
}

type serviceImpl struct {
	repo repository
}

func NewService(pool *pgxpool.Pool) Service {
	return &serviceImpl{repo: newRepository(pool)}
}

func (s *serviceImpl) Create(ctx context.Context, name, adminEmail string) (*Network, error) {
	name = strings.TrimSpace(name)
	if name == "" {
		return nil, ErrInvalidName
	}

	adminEmail, err := utils.NormalizeEmail(adminEmail)
	if err != nil {
		return nil, err
	}

	network, err := s.repo.create(ctx, name, adminEmail)
	if err != nil {
		return nil, err
	}

	err = s.AddMembers(ctx, network.ID, []string{adminEmail})
	if err != nil {
		return nil, err
	}

	return network, nil
}

func (s *serviceImpl) GetByID(ctx context.Context, id string) (*Network, error) {
	n, err := s.repo.getByID(ctx, id)
	if errors.Is(err, errNotFound) {
		return nil, ErrNotFound
	}
	return n, err
}

func (s *serviceImpl) SetName(ctx context.Context, id, name string) error {
	name = strings.TrimSpace(name)
	if name == "" {
		return ErrInvalidName
	}

	err := s.repo.updateName(ctx, id, name)
	if errors.Is(err, errNotFound) {
		return ErrNotFound
	}
	return err
}

func (s *serviceImpl) AddMembers(ctx context.Context, networkID string, emails []string) error {
	for _, email := range emails {
		normalized, err := utils.NormalizeEmail(email)
		if err != nil {
			return fmt.Errorf("invalid email: %w", err)
		}
		if err := s.repo.addMember(ctx, networkID, normalized); err != nil {
			return err
		}
	}
	return nil
}

func (s *serviceImpl) RemoveMember(ctx context.Context, networkID, email string) error {
	email, err := utils.NormalizeEmail(email)
	if err != nil {
		return fmt.Errorf("invalid email: %w", err)
	}
	return s.repo.removeMember(ctx, networkID, email)
}

func (s *serviceImpl) ListForEmail(ctx context.Context, email string) ([]*Network, error) {
	email, err := utils.NormalizeEmail(email)
	if err != nil {
		return nil, fmt.Errorf("invalid email: %w", err)
	}
	return s.repo.getNetworksForEmail(ctx, email)
}

func (s *serviceImpl) IsMember(ctx context.Context, networkID, email string) (bool, error) {
	email, err := utils.NormalizeEmail(email)
	if err != nil {
		return false, err
	}
	return s.repo.isMember(ctx, networkID, email)
}

func (s *serviceImpl) SetOpenStreamCapacity(ctx context.Context, networkID string, capacity int) error {
	if capacity < 0 {
		capacity = 0
	}
	err := s.repo.setOpenStreamCapacity(ctx, networkID, capacity)
	if errors.Is(err, errNotFound) {
		return ErrNotFound
	}
	return err
}

func (s *serviceImpl) IncrementOpenStreamCount(ctx context.Context, networkID string) error {
	err := s.repo.incrementOpenStreamCount(ctx, networkID)
	if errors.Is(err, errNotFound) {
		return ErrNotFound
	}
	if errors.Is(err, errCapacityExceeded) {
		return ErrCapacityExceeded
	}
	return err
}

func (s *serviceImpl) DecrementOpenStreamCount(ctx context.Context, networkID string) error {
	err := s.repo.decrementOpenStreamCount(ctx, networkID)
	if errors.Is(err, errNotFound) {
		return ErrNotFound
	}
	return err
}