package main

import (
	"os"
	"path/filepath"
	"runtime"
	"strings"
)

type Config struct {
  Streams map[string]string // stream in the form stream::name=url
  DataDir  string  // location of templates/ and static/
  Name string // name of this instance
	ListenAddress     string  // address the webserver listens on
}

func GetConfigLocation() string {
	home := os.Getenv("HOME")
	appdata := os.Getenv("APPDATA")
	switch runtime.GOOS {
	case "windows":
		return filepath.Join(appdata, "grimoire")
	case "darwin":
		return filepath.Join(home, "Library", "Application Support", "grimoire")
	case "plan9":
		return filepath.Join(home, "lib", "grimoire")
	default:
		return filepath.Join(home, ".config", "grimoire")
	}
}

func ensureConfigLocationExists() {
	fileInfo, err := os.Stat(GetConfigLocation())

	if os.IsNotExist(err) {
		os.MkdirAll(GetConfigLocation(), os.ModePerm)
	} else if !fileInfo.IsDir() {
		panic("Config location is not a directory!")
	}
}

func ReadConfig() *Config {
	ensureConfigLocationExists()
	return parseConfig(filepath.Join(GetConfigLocation(), "grimoire.conf"))
}

func (self *Config) Write() error {
	ensureConfigLocationExists()
	return writeConfig(self, filepath.Join(GetConfigLocation(), "grimoire.conf"))
}

func writeConfig(cfg *Config, configFile string) error {
	f, err := os.Create(configFile)
	if err != nil {
		return err
	}

	defer f.Close()

	f.WriteString("listenAddress=" + cfg.ListenAddress + "\n")
	f.WriteString("dataDir=" + cfg.DataDir + "\n")
	f.WriteString("name=" + cfg.Name + "\n")
	for k, v := range cfg.Streams {
	  f.WriteString("stream::" + k + "=" + v)
	}
	return nil
}

func parseConfig(configFile string) *Config {
	f, err := os.ReadFile(configFile)
	cfg := &Config{}
	cfg.Streams = make(map[string]string)
	if err != nil {
		return cfg
	}

	fileData := string(f[:])

	lines := strings.Split(fileData, "\n")

	for _, l := range lines {
		if len(l) == 0 {
			continue
		}
		if !strings.Contains(l, "=") {
			panic("Malformed config not in INI format")
		}

		kvp := strings.Split(l, "=")
		k := strings.TrimSpace(kvp[0])
		v := strings.TrimSpace(kvp[1])
		switch k {
		case "listenAddress":
			cfg.ListenAddress = v
		case "dataDir":
			cfg.DataDir = v
		case "name":
		  cfg.Name = v
    default:
      if strings.HasPrefix(k, "stream::") {
        stream := strings.Split(k, "stream::")[1]
        if len(stream) == 0 {
          panic("stream in config has no name!")
        }
        cfg.Streams[stream] = v
      } else {
		  	panic("Unrecognized config option: " + k)
		  }
		}
	}
	return cfg
}