package main

import (
	"encoding/json"
	"errors"
	"fmt"
	"os"
	"path/filepath"
	"time"
)

const (
	configDirName  = ".htsy"
	configFileName = "config.json"
	defaultBaseURL = "https://htsy-gateway.cpshelp.cn"
)

type Config struct {
	BaseURL   string    `json:"baseUrl,omitempty"`
	Token     string    `json:"token,omitempty"`
	Username  string    `json:"username,omitempty"`
	LoginKind string    `json:"loginKind,omitempty"`
	UpdatedAt time.Time `json:"updatedAt,omitempty"`
}

func defaultConfigPath() (string, error) {
	if value := os.Getenv("HTSY_CONFIG"); value != "" {
		return value, nil
	}

	home, err := os.UserHomeDir()
	if err != nil {
		return "", fmt.Errorf("resolve home directory: %w", err)
	}

	return filepath.Join(home, configDirName, configFileName), nil
}

func resolveConfigPath(path string) (string, error) {
	if path != "" {
		return path, nil
	}
	return defaultConfigPath()
}

func loadConfig(path string) (Config, error) {
	resolved, err := resolveConfigPath(path)
	if err != nil {
		return Config{}, err
	}

	data, err := os.ReadFile(resolved)
	if errors.Is(err, os.ErrNotExist) {
		return Config{BaseURL: defaultBaseURL}, nil
	}
	if err != nil {
		return Config{}, fmt.Errorf("read config %s: %w", resolved, err)
	}

	var cfg Config
	if err := json.Unmarshal(data, &cfg); err != nil {
		return Config{}, fmt.Errorf("parse config %s: %w", resolved, err)
	}
	if cfg.BaseURL == "" {
		cfg.BaseURL = defaultBaseURL
	}

	return cfg, nil
}

func saveConfig(path string, cfg Config) error {
	resolved, err := resolveConfigPath(path)
	if err != nil {
		return err
	}

	if cfg.BaseURL == "" {
		cfg.BaseURL = defaultBaseURL
	}
	cfg.UpdatedAt = time.Now().UTC()

	dir := filepath.Dir(resolved)
	if err := os.MkdirAll(dir, 0o700); err != nil {
		return fmt.Errorf("create config dir %s: %w", dir, err)
	}

	data, err := json.MarshalIndent(cfg, "", "  ")
	if err != nil {
		return fmt.Errorf("encode config: %w", err)
	}
	data = append(data, '\n')

	if err := os.WriteFile(resolved, data, 0o600); err != nil {
		return fmt.Errorf("write config %s: %w", resolved, err)
	}

	return nil
}

func clearLogin(path string) error {
	cfg, err := loadConfig(path)
	if err != nil {
		return err
	}
	cfg.Token = ""
	cfg.Username = ""
	cfg.LoginKind = ""
	return saveConfig(path, cfg)
}