package lsp

import (
	"errors"
	"io"
	"io/ioutil"
	"os"
	"os/exec"
	"path/filepath"
	"strings"

	"github.com/zyedidia/micro/v2/internal/config"
	"gopkg.in/yaml.v2"
)

var ErrManualInstall = errors.New("Requires manual installation")

type Config struct {
	Languages map[string]Language `yaml:"language"`
}

type Language struct {
	Command string     `yaml:"command"`
	Args    []string   `yaml:"args"`
	Install [][]string `yaml:"install"`
}

var conf *Config

func GetLanguage(lang string) (Language, bool) {
	if conf != nil {
		l, ok := conf.Languages[lang]
		return l, ok
	}
	return Language{}, false
}

func Init() error {
	var servers []byte
	var err error

	filename := filepath.Join(config.ConfigDir, "lsp.yaml")
	if _, e := os.Stat(filename); e == nil {
		servers, err = ioutil.ReadFile(filename)
		if err != nil {
			servers = servers_internal
		}
	} else {
		err = ioutil.WriteFile(filename, servers_internal, 0644)
		servers = servers_internal
	}

	conf, err = LoadConfig(servers)
	return err
}

func LoadConfig(data []byte) (*Config, error) {
	var conf Config
	if err := yaml.Unmarshal(data, &conf); err != nil {
		return nil, err
	}

	return &conf, nil
}

func (l Language) Installed() bool {
	_, err := exec.LookPath(l.Command)
	if err != nil {
		return false
	}

	return true
}

func (l Language) DoInstall(w io.Writer) error {
	if l.Installed() {
		return nil
	}

	if len(l.Install) == 0 {
		return ErrManualInstall
	}

	for _, c := range l.Install {
		io.WriteString(w, strings.Join(c, " ")+"\n")
		cmd := exec.Command(c[0], c[1:]...)
		err := cmd.Run()
		if err != nil {
			return err
		}
	}

	return nil
}