package config

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

type Config struct {
	ChannelID            string `json:"channel_id"`
	CheckIntervalMinutes int    `json:"check_interval_minutes"`
	MinecraftVersion     string `json:"minecraft_version"`
	FabricLoaderVersion  string `json:"fabric_loader_version"`
	LoaderMetaVersion    string `json:"loader_meta_version"`
	JavaPath             string `json:"java_path"`
	ServerLocation       string `json:"server_location"`
	BackupLocation       string `json:"backup_location"`
	MergePreCommand      string `json:"merge_pre_command"`
	MergePostCommand     string `json:"merge_post_command"`
	ModrinthMods         []Mod  `json:"modrinth_mods"`
}

type Mod struct {
	Slug    string
	Version string
}

func (m Mod) Pinned() bool {
	return m.Version != ""
}

func (m Mod) MarshalJSON() ([]byte, error) {
	if m.Version == "" {
		return json.Marshal(m.Slug)
	}
	return json.Marshal(modObject{Slug: m.Slug, Version: m.Version})
}

func (m *Mod) UnmarshalJSON(data []byte) error {
	var slug string
	if err := json.Unmarshal(data, &slug); err == nil {
		m.Slug = slug
		m.Version = ""
		return nil
	}

	var obj modObject
	if err := json.Unmarshal(data, &obj); err != nil {
		return err
	}
	m.Slug = obj.Slug
	m.Version = obj.Version
	return nil
}

type modObject struct {
	Slug    string `json:"slug"`
	Version string `json:"version"`
}

const Dir = "config"

func Path() string {
	return filepath.Join(Dir, "config.json")
}

func APIPath() string {
	return filepath.Join(Dir, "api.json")
}

func Load() (*Config, error) {
	data, err := os.ReadFile(Path())
	if err != nil {
		return nil, err
	}

	var c Config
	if err := json.Unmarshal(data, &c); err != nil {
		return nil, err
	}

	return &c, nil
}

func Save(cfg *Config) error {
	if err := os.MkdirAll(Dir, 0o755); err != nil {
		return err
	}

	data, err := json.MarshalIndent(cfg, "", "  ")
	if err != nil {
		return err
	}
	return os.WriteFile(Path(), append(data, '\n'), 0o644)
}