package main

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

	"git.milar.in/milarin/configfile"
)

type Config struct {
	OutputDir  string `json:"output_dir"`
	OutputFile string `json:"output_file"`

	OS   []string `json:"os"`
	Arch []string `json:"arch"`

	Silent         bool `json:"silent"`
	NoCompress     bool `json:"no_compress"`
	NumThreads     int  `json:"num_threads"`
	KeepDebugFlags bool `json:"debug_flags"`
}

func SetFlagIfDefault[T comparable](flag *T, newValue T, defaultValue T) {
	if *flag == defaultValue {
		*flag = newValue
	}
}

func LoadConfig() error {
	configFilePath, err := configfile.Path("json")
	if err != nil {
		return err
	}

	file, err := os.Open(configFilePath)
	if err != nil {
		return err
	}
	defer file.Close()

	cfg := &Config{}
	if err := json.NewDecoder(file).Decode(cfg); err != nil {
		if errors.Is(err, io.EOF) {
			return nil
		}
		return err
	}

	SetFlagIfDefault(OutputDir, cfg.OutputDir, DefaultOutputDir)
	SetFlagIfDefault(OutputFile, cfg.OutputFile, DefaultOutputFile)
	SetFlagIfDefault(OS, strings.Join(cfg.OS, ","), DefaultOS)
	SetFlagIfDefault(Arch, strings.Join(cfg.Arch, ","), DefaultArch)
	SetFlagIfDefault(Silent, cfg.Silent, DefaultSilent)
	SetFlagIfDefault(NoCompress, cfg.NoCompress, DefaultNoCompress)
	SetFlagIfDefault(NumThreads, cfg.NumThreads, DefaultNumThreads)
	SetFlagIfDefault(KeepDebugFlags, cfg.KeepDebugFlags, DefaultKeepDebugFlags)

	return nil
}

func SaveConfig() (string, error) {
	configFilePath, err := configfile.Path("json")
	if err != nil {
		return "", err
	}

	if err := os.MkdirAll(filepath.Dir(configFilePath), 0744); err != nil {
		return configFilePath, err
	}

	file, err := os.Create(configFilePath)
	if err != nil {
		return configFilePath, err
	}
	defer file.Close()

	enc := json.NewEncoder(file)
	enc.SetIndent("", "\t")

	cfg := &Config{
		OutputDir:      *OutputDir,
		OutputFile:     *OutputFile,
		OS:             strings.Split(*OS, ","),
		Arch:           strings.Split(*Arch, ","),
		Silent:         *Silent,
		NoCompress:     *NoCompress,
		NumThreads:     *NumThreads,
		KeepDebugFlags: *KeepDebugFlags,
	}

	if err := enc.Encode(cfg); err != nil {
		return configFilePath, err
	}

	return configFilePath, nil
}