package main

import (
	"errors"
	"fmt"
	"io/fs"
	"os"

	"github.com/adrg/xdg"
	"gopkg.in/yaml.v3"
)

type config struct {
	Languages []struct {
		Name       string   `yaml:"name"`
		Timeframes []string `yaml:"timeframes"`
	} `yaml:"languages"`
}

func loadConfig() (*config, error) {
	cfgPath, err := xdg.ConfigFile("trending/config.yaml")
	if err != nil {
		return nil, fmt.Errorf("could not get config file path: %w", err)
	}
	fi, err := os.Open(cfgPath)
	if err != nil {
		if !errors.Is(err, fs.ErrNotExist) {
			return nil, fmt.Errorf("could not open config file: %w", err)
		}
		if err := createDefaultConfig(cfgPath); err != nil {
			return nil, fmt.Errorf("could not create default config: %w", err)
		}
		return loadConfig()
	}
	defer fi.Close()

	var cfg config
	if err := yaml.NewDecoder(fi).Decode(&cfg); err != nil {
		return nil, fmt.Errorf("could not decode config: %w", err)
	}
	return &cfg, nil
}

func createDefaultConfig(cfgPath string) error {
	fi, err := os.Create(cfgPath)
	if err != nil {
		return err
	}
	defer fi.Close()
	_, err = fi.Write(defaultConfig)
	return err
}

var defaultConfig = []byte(`languages:
  - name: go
    timeframes:
      - daily
      - weekly
      - monthly
  - name: rust
    timeframes:
      - daily
      - weekly
      - monthly
`)