package hmsecrets

import (
	"errors"
	"fmt"
	"os"
	"path"
	"runtime"

	"gopkg.in/yaml.v3"
)

type config struct {
	APIBase    string `yaml:"api-base"`
	CA         string `yaml:"ca"`
	ClientCert string `yaml:"client-cert"`
	ClientKey  string `yaml:"client-key"`
}

func mustLoadConfig() config {
	var baseConfigDir string
	var err error
	switch runtime.GOOS {
	case "windows":
		fallthrough
	case "linux":
		baseConfigDir, err = os.UserConfigDir()
		if err != nil {
			panic(fmt.Errorf("determining user config dir: %w", err))
		}
	case "darwin":
		// We want $HOME/.config in macOS.
		homeDir, err := os.UserHomeDir()
		if err != nil {
			panic(fmt.Errorf("determining user home dir: %w", err))
		}
		baseConfigDir = path.Join(homeDir, ".config")
	}

	configDir := path.Join(baseConfigDir, "hmsecrets")

	configBytes, err := os.ReadFile(path.Join(configDir, "config.yaml"))
	if err != nil {
		panic(fmt.Errorf("reading config file: %w", err))
	}
	var conf config
	err = yaml.Unmarshal(configBytes, &conf)
	if err != nil {
		panic(fmt.Errorf("parsing config file: %w", err))
	}

	if conf.APIBase == "" {
		panic(errors.New("api base must be present in config"))
	}

	if conf.CA == "" {
		conf.CA = path.Join(configDir, "ca.crt")
	}
	if !fileAccesible(conf.CA) {
		panic(fmt.Errorf("ca file '%s' does not exist or is inaccesible", conf.CA))
	}

	if conf.ClientCert == "" {
		conf.ClientCert = path.Join(configDir, "client.crt")
	}
	if !fileAccesible(conf.ClientCert) {
		panic(fmt.Errorf("client cert file '%s' does not exist or is inaccesible", conf.ClientCert))
	}

	if conf.ClientKey == "" {
		conf.ClientKey = path.Join(configDir, "client.key")
	}
	if !fileAccesible(conf.ClientKey) {
		panic(fmt.Errorf("client key file '%s' does not exist or is inaccesible", conf.ClientKey))
	}

	return conf
}

func fileAccesible(f string) bool {
	_, err := os.Stat(f)
	return err == nil
}