package config

import (
	"fmt"
	"os"
	"path/filepath"
	"strconv"
	"strings"

	"github.com/BurntSushi/toml"
)

type Config struct {
	Server  ServerConfig  `toml:"server"`
	Storage StorageConfig `toml:"storage"`
	Auth    AuthConfig    `toml:"auth"`
	Landing LandingConfig `toml:"landing"`
}

type ServerConfig struct {
	Host    string `toml:"host"`
	Port    int    `toml:"port"`
	BaseURL string `toml:"base_url"`
}

type StorageConfig struct {
	DataDir string `toml:"data_dir"`
}

type AuthConfig struct {
	RegistrationEnabled bool `toml:"registration_enabled"`
}

type LandingConfig struct {
	Enabled     bool   `toml:"enabled"`
	DefaultLang string `toml:"default_lang"`
}

func Default() Config {
	return Config{
		Server: ServerConfig{
			Host:    "0.0.0.0",
			Port:    3000,
			BaseURL: "http://localhost:3000",
		},
		Storage: StorageConfig{
			DataDir: "./data",
		},
		Auth: AuthConfig{
			RegistrationEnabled: true,
		},
		Landing: LandingConfig{
			Enabled:     true,
			DefaultLang: "ru",
		},
	}
}

func Load(configPath string) (Config, error) {
	cfg := Default()

	if envPath := os.Getenv("POLAR_CONFIG"); envPath != "" && configPath == "" {
		configPath = envPath
	}
	if configPath == "" {
		if _, err := os.Stat("polar.toml"); err == nil {
			configPath = "polar.toml"
		}
	}

	if configPath != "" {
		data, err := os.ReadFile(configPath)
		if err != nil {
			return cfg, fmt.Errorf("read config file %s: %w", configPath, err)
		}
		if err := toml.Unmarshal(data, &cfg); err != nil {
			return cfg, fmt.Errorf("parse config file %s: %w", configPath, err)
		}
	}

	applyEnv(&cfg)

	cfg.Server.BaseURL = strings.TrimRight(cfg.Server.BaseURL, "/")
	if cfg.Server.BaseURL == "" {
		host := cfg.Server.Host
		if host == "0.0.0.0" || host == "" {
			host = "localhost"
		}
		cfg.Server.BaseURL = fmt.Sprintf("http://%s:%d", host, cfg.Server.Port)
	}
	if cfg.Landing.DefaultLang != "en" && cfg.Landing.DefaultLang != "ru" {
		cfg.Landing.DefaultLang = "ru"
	}

	return cfg, nil
}

func applyEnv(cfg *Config) {
	getEnv := os.Getenv

	if v := getEnv("POLAR_SERVER_HOST"); v != "" {
		cfg.Server.Host = v
	}
	if v := getEnv("POLAR_HOST"); v != "" {
		cfg.Server.Host = v
	}
	if v := getEnv("POLAR_SERVER_PORT"); v != "" {
		if p, err := strconv.Atoi(v); err == nil && p > 0 {
			cfg.Server.Port = p
		}
	}
	if v := getEnv("POLAR_PORT"); v != "" {
		if p, err := strconv.Atoi(v); err == nil && p > 0 {
			cfg.Server.Port = p
		}
	}
	if v := getEnv("POLAR_SERVER_BASE_URL"); v != "" {
		cfg.Server.BaseURL = v
	}
	if v := getEnv("POLAR_BASE_URL"); v != "" {
		cfg.Server.BaseURL = v
	}
	if v := getEnv("POLAR_STORAGE_DATA_DIR"); v != "" {
		cfg.Storage.DataDir = v
	}
	if v := getEnv("POLAR_DATA_DIR"); v != "" {
		cfg.Storage.DataDir = v
	}
	if v := getEnv("POLAR_AUTH_REGISTRATION_ENABLED"); v != "" {
		if b, err := strconv.ParseBool(v); err == nil {
			cfg.Auth.RegistrationEnabled = b
		}
	}
	if v := getEnv("POLAR_LANDING_ENABLED"); v != "" {
		if b, err := strconv.ParseBool(v); err == nil {
			cfg.Landing.Enabled = b
		}
	}
	if v := getEnv("POLAR_LANDING_DEFAULT_LANG"); v != "" {
		cfg.Landing.DefaultLang = strings.ToLower(strings.TrimSpace(v))
	}
}

func (c Config) Addr() string {
	return fmt.Sprintf("%s:%d", c.Server.Host, c.Server.Port)
}

func (c Config) DBPath() string {
	return filepath.Join(c.Storage.DataDir, "polar.db")
}

func (c Config) ReposDir() string {
	return filepath.Join(c.Storage.DataDir, "repos")
}