package config

import (
	"flag"
	"fmt"
	"os"

	"github.com/peterbourgon/ff/v3"
)

type Config struct {
	Github Github
	Port   int
}

type Github struct {
	App      App
	Token    string
	APIv3URL string
}

type App struct {
	ID         int64  `split_words:"true"`
	PrivateKey string `split_words:"true"`
}

func New() (*Config, error) {
	cfg := &Config{
		Github: Github{App: App{}, APIv3URL: "https://api.github.com/"},
		Port:   8080,
	}
	fs := flag.NewFlagSet("github-exporter", flag.ContinueOnError)

	// github config
	fs.Int64Var(&cfg.Github.App.ID, "github-app-id", 0, "integration ID for github app")
	// TODO: this should be a path to a private key
	fs.StringVar(&cfg.Github.App.PrivateKey, "github-app-private-key", "", "private key for github app")
	fs.StringVar(&cfg.Github.Token, "github-token", "", "github token to use for authentication. mutually exclusive with app config")
	// server config
	fs.IntVar(&cfg.Port, "port", cfg.Port, "port to serve on")

	if err := ff.Parse(fs, os.Args[1:], ff.WithEnvVarNoPrefix()); err != nil {
		return nil, err
	}

	if err := cfg.Validate(); err != nil {
		return nil, err
	}

	return cfg, nil
}

func (c *Config) Validate() error {
	if c.Github.App == (App{}) && c.Github.Token == "" {
		return fmt.Errorf("either github app credentials or token is required")
	}

	return nil
}