// Package config keeps the Hammerhead address and token between runs.
package config

import (
	"encoding/json"
	"errors"
	"os"
	"path/filepath"
	"strings"
)

type Config struct {
	Hammerhead string `json:"hammerhead"`
	Token      string `json:"token"`
}

// Path is where `shark login` saves the settings; SHARK_CONFIG overrides it.
func Path() (string, error) {
	if p := os.Getenv("SHARK_CONFIG"); p != "" {
		return p, nil
	}
	dir, err := os.UserConfigDir()
	if err != nil {
		return "", err
	}
	return filepath.Join(dir, "shark", "config.json"), nil
}

// Load reads the saved settings, then lets SHARK_HAMMERHEAD and SHARK_TOKEN override them.
// A missing file is not an error.
func Load() (Config, error) {
	var c Config
	p, err := Path()
	if err == nil {
		b, rerr := os.ReadFile(p)
		switch {
		case rerr == nil:
			if err := json.Unmarshal(b, &c); err != nil {
				return c, errors.New(p + " is not valid JSON: " + err.Error())
			}
		case !errors.Is(rerr, os.ErrNotExist):
			return c, rerr
		}
	}
	if v := os.Getenv("SHARK_HAMMERHEAD"); v != "" {
		c.Hammerhead = v
	}
	if v := os.Getenv("SHARK_TOKEN"); v != "" {
		c.Token = v
	}
	c.Hammerhead = strings.TrimRight(c.Hammerhead, "/")
	return c, nil
}

// Save writes the settings so that only the user can read them (the token is a credential).
func Save(c Config) (string, error) {
	p, err := Path()
	if err != nil {
		return "", err
	}
	if err := os.MkdirAll(filepath.Dir(p), 0o700); err != nil {
		return "", err
	}
	b, _ := json.MarshalIndent(c, "", "  ")
	return p, os.WriteFile(p, append(b, '\n'), 0o600)
}