package bootstrap

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

	"gopkg.in/yaml.v3"
)

// NebulaHost describes the contents of a `./nebula/hosts/<hostname>.yml` file.
type NebulaHost struct {
	Name       string `yaml:"name"`
	IP         string `yaml:"ip"`
	PublicAddr string `yaml:"public_addr,omitempty"`
}

// GarageHostInstance describes a single garage instance running on a host.
type GarageHostInstance struct {
	RPCPort   int `yaml:"rpc_port"`
	S3APIPort int `yaml:"s3_api_port"`
	WebPort   int `yaml:"web_port"`
}

// GarageHost describes the contents of a `./garage/hosts/<hostname>.yml` file.
type GarageHost struct {
	Instances []GarageHostInstance `yaml:"instances"`
}

// Host consolidates all information about a single host from the bootstrap
// file.
type Host struct {
	Name   string
	Nebula NebulaHost
	Garage *GarageHost
}

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(NebulaHostsDirPath, "*.yml")

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

		for _, nebulaHostPath := range nebulaHostFiles {

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

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

			hosts[hostName] = Host{
				Name:   hostName,
				Nebula: nebulaHost,
			}
		}
	}

	for hostName, host := range hosts {

		garageHostPath := filepath.Join(GarageHostsDirPath, hostName+".yml")

		var garageHost GarageHost
		if err := readAsYaml(&garageHost, garageHostPath); errors.Is(err, fs.ErrNotExist) {
			continue
		} else if err != nil {
			return nil, fmt.Errorf("reading %q as yaml: %w", garageHostPath, err)
		}

		host.Garage = &garageHost
		hosts[hostName] = host
	}

	return hosts, nil
}