package bootstrap

import (
	"fmt"
	"io/fs"
	"path/filepath"
	"strings"

	"gopkg.in/yaml.v3"
)

const (
	hostsDirPath = "hosts"
)

// NebulaHost describes the nebula configuration of a Host which is relevant for
// other hosts to know.
type NebulaHost struct {
	IP         string `yaml:"ip"`
	PublicAddr string `yaml:"public_addr,omitempty"`
}

// GarageHost describes a single garage instance in the GarageHost.
type GarageHostInstance struct {
	RPCPort   int `yaml:"rpc_port"`
	S3APIPort int `yaml:"s3_api_port"`
}

// GarageHost describes the garage configuration of a Host which is relevant for
// other hosts to know.
type GarageHost struct {
	Instances []GarageHostInstance `yaml:"instances"`
}

// Host consolidates all information about a single host from the bootstrap
// file.
type Host struct {
	Name   string      `yaml:"name"`
	Nebula NebulaHost  `yaml:"nebula"`
	Garage *GarageHost `yaml:"garage,omitempty"`
}

func loadHosts(bootstrapFS fs.FS) (map[string]Host, error) {

	hosts := map[string]Host{}

	readAsYaml := func(into interface{}, path string) error {
		b, err := fs.ReadFile(bootstrapFS, path)
		if err != nil {
			return fmt.Errorf("reading file from fs: %w", err)
		}

		return yaml.Unmarshal(b, into)
	}

	globPath := filepath.Join(hostsDirPath, "*.yml")

	hostPaths, err := fs.Glob(bootstrapFS, globPath)
	if err != nil {
		return nil, fmt.Errorf("listing host files at %q in fs: %w", globPath, err)
	}

	for _, hostPath := range hostPaths {

		hostName := filepath.Base(hostPath)
		hostName = strings.TrimSuffix(hostName, filepath.Ext(hostName))

		var host Host
		if err := readAsYaml(&host, hostPath); err != nil {
			return nil, fmt.Errorf("reading %q as yaml: %w", hostPath, err)
		}

		hosts[hostName] = host
	}

	if len(hosts) == 0 {
		return nil, fmt.Errorf("failed to load any hosts from fs")
	}

	return hosts, nil
}