package xboard

import (
	"context"
	"fmt"

	"github.com/sagernet/sing-box/adapter"
	boxService "github.com/sagernet/sing-box/adapter/service"
	C "github.com/sagernet/sing-box/constant"
	"github.com/sagernet/sing-box/log"
	"github.com/sagernet/sing-box/option"
)

type multiNodeService struct {
	boxService.Adapter
	services []adapter.Service
}

func newMultiNodeService(ctx context.Context, logger log.ContextLogger, tag string, options option.XBoardServiceOptions) (adapter.Service, error) {
	expanded := expandNodeOptions(options)
	services := make([]adapter.Service, 0, len(expanded))
	for i, node := range expanded {
		nodeTag := expandedNodeTag(tag, i, options.Nodes[i], node)
		service, err := newSingleService(ctx, logger, nodeTag, node)
		if err != nil {
			return nil, fmt.Errorf("create xboard node service %s: %w", nodeTag, err)
		}
		services = append(services, service)
	}
	return &multiNodeService{
		Adapter:  boxService.NewAdapter(C.TypeXBoard, tag),
		services: services,
	}, nil
}

func expandNodeOptions(base option.XBoardServiceOptions) []option.XBoardServiceOptions {
	if len(base.Nodes) == 0 {
		return []option.XBoardServiceOptions{base}
	}
	result := make([]option.XBoardServiceOptions, 0, len(base.Nodes))
	for _, node := range base.Nodes {
		child := base
		child.Nodes = nil
		if node.PanelURL != "" {
			child.PanelURL = node.PanelURL
		}
		if node.ConfigPanelURL != "" {
			child.ConfigPanelURL = node.ConfigPanelURL
		}
		if node.UserPanelURL != "" {
			child.UserPanelURL = node.UserPanelURL
		}
		if node.Key != "" {
			child.Key = node.Key
		}
		if node.NodeID != 0 {
			child.NodeID = node.NodeID
		}
		if node.ConfigNodeID != 0 {
			child.ConfigNodeID = node.ConfigNodeID
		}
		if node.UserNodeID != 0 {
			child.UserNodeID = node.UserNodeID
		}
		if node.NodeType != "" {
			child.NodeType = node.NodeType
		}
		if node.SyncInterval != 0 {
			child.SyncInterval = node.SyncInterval
		}
		if node.ReportInterval != 0 {
			child.ReportInterval = node.ReportInterval
		}
		result = append(result, child)
	}
	return result
}

func expandedNodeTag(baseTag string, index int, entry option.XBoardNodeOptions, node option.XBoardServiceOptions) string {
	nodeTag := ""
	if entry.Tag != "" {
		nodeTag = entry.Tag
	}
	if nodeTag == "" && node.NodeID != 0 {
		nodeTag = fmt.Sprintf("%d", node.NodeID)
	}
	if nodeTag == "" {
		nodeTag = fmt.Sprintf("%d", index+1)
	}
	if baseTag == "" {
		return "xboard-" + nodeTag
	}
	return fmt.Sprintf("%s-%s", baseTag, nodeTag)
}

func (s *multiNodeService) Start(stage adapter.StartStage) error {
	for _, service := range s.services {
		if err := service.Start(stage); err != nil {
			return err
		}
	}
	return nil
}

func (s *multiNodeService) Close() error {
	for i := len(s.services) - 1; i >= 0; i-- {
		if err := s.services[i].Close(); err != nil {
			return err
		}
	}
	return nil
}