package channel

import (
	"errors"
	"sync"

	"pay-bridge/internal/model"
)

var (
	ErrChannelNotFound = errors.New("channel not found")
	ErrNotSupported    = errors.New("operation not supported by this channel")
)

var globalRegistry = &Registry{}

// Registry 渠道注册表
type Registry struct {
	mu        sync.RWMutex
	factories map[string]ChannelFactory
}

// Register 注册渠道工厂（供各渠道包在 init() 中调用）
func Register(channelCode string, factory ChannelFactory) {
	globalRegistry.Register(channelCode, factory)
}

func (r *Registry) Register(channelCode string, factory ChannelFactory) {
	r.mu.Lock()
	defer r.mu.Unlock()
	if r.factories == nil {
		r.factories = make(map[string]ChannelFactory)
	}
	r.factories[channelCode] = factory
}

// Get 根据渠道码、商户配置和网关地址获取渠道实例
func Get(channelCode string, config *model.ChannelConfig, urls URLs) (PaymentChannel, error) {
	return globalRegistry.Get(channelCode, config, urls)
}

func (r *Registry) Get(channelCode string, config *model.ChannelConfig, urls URLs) (PaymentChannel, error) {
	r.mu.RLock()
	factory, ok := r.factories[channelCode]
	r.mu.RUnlock()
	if !ok {
		return nil, ErrChannelNotFound
	}
	return factory(config, urls), nil
}

// List 列出已注册的渠道码
func List() []string {
	return globalRegistry.List()
}

func (r *Registry) List() []string {
	r.mu.RLock()
	defer r.mu.RUnlock()
	codes := make([]string, 0, len(r.factories))
	for code := range r.factories {
		codes = append(codes, code)
	}
	return codes
}