package main

import (
	"encoding/json"
	"errors"
	"fmt"
	"io/ioutil"
	"log"
	"os"
	"strings"
)

type ModList struct {
	Mods []Mod `json:"mods"`
}

type Mod struct {
	Name    string `json:"name"`
	Enabled bool   `json:"enabled,string"`
}

// List mods installed in the factorio/mods directory
func listInstalledMods(modDir string) ([]string, error) {
	result := []string{}

	files, err := ioutil.ReadDir(modDir)
	if err != nil {
		log.Printf("Error listing installed mods")
		return result, err
	}
	for _, f := range files {
		if f.Name() == "mod-list.json" {
			continue
		}
		result = append(result, f.Name())
	}

	return result, nil
}

func rmMod(modName string) error {
	removed := false
	if modName == "" {
		return errors.New("No mod name provided.")
	}
	// Get list of installed mods
	installedMods, err := listInstalledMods(config.FactorioModsDir)
	if err != nil {
		log.Printf("Error in remove mod list: %s", err)
		return err
	}

	// Check if provided mod matches one thats installed else return err
	for _, mod := range installedMods {
		if strings.Contains(mod, modName) {
			log.Printf("Removing mod: %s", mod)
			err := os.Remove(config.FactorioModsDir + "/" + mod)
			if err != nil {
				log.Printf("Error removing mod %s: %s", mod, err)
				return err
			}
			log.Printf("Removed mod: %s", mod)
			removed = true
		}
	}

	if !removed {
		log.Printf("Did not remove mod: %s", modName)
		return errors.New(fmt.Sprintf("Did not remove mod: %s", modName))
	}

	return nil
}

// Parses mod-list.json file in factorio/mods
// returns ModList struct
func parseModList() (ModList, error) {
	var mods ModList
	modListFile := config.FactorioDir + "/mods/mod-list.json"

	modList, err := ioutil.ReadFile(modListFile)
	if err != nil {
		log.Printf("Error reading mod-list.json file: %s", err)
		return mods, err
	}

	err = json.Unmarshal(modList, &mods)
	if err != nil {
		log.Printf("Error parsing mod-list.json JSON: %s", err)
		return mods, err
	}

	return mods, nil
}

// Toggles Enabled boolean for mod specified in name parameter in mod-list.json file
func (m *ModList) toggleMod(name string) error {
	found := false
	status := false

	for i := range m.Mods {
		if m.Mods[i].Name == name {
			found = true
			if m.Mods[i].Enabled == true {
				m.Mods[i].Enabled = false
			} else {
				m.Mods[i].Enabled = true
				status = true
			}
		}
	}

	if found {
		m.save()
		log.Printf("Mod: %s was toggled to %v", name, status)
	}

	return nil
}

// Saves ModList object to mod-list.json file
// Overwrites old file
func (m ModList) save() error {
	modListFile := config.FactorioDir + "/mods/mod-list.json"
	b, _ := json.MarshalIndent(m, "", "    ")

	err := ioutil.WriteFile(modListFile, b, 0644)
	if err != nil {
		log.Printf("Error writing to mod-list.json file: %s", err)
	}

	return nil
}

//TODO Add method to allow downloading all installed mods in zip file
//TODO Add method for uploading new mods