package config

import (
	"fmt"
	"os"
	"strings"
)

const (
	EnvListenAddr = "SUB2API_CRM_LISTEN_ADDR"
	EnvSQLiteDSN  = "SUB2API_CRM_SQLITE_DSN"
	EnvAdminToken = "SUB2API_CRM_ADMIN_TOKEN"

	DefaultListenAddr = ":8080"
	DefaultSQLiteDSN  = "file:sub2api-cn-relay-manager.db?_foreign_keys=on&_busy_timeout=5000"
)

type ServerConfig struct {
	ListenAddr string
}

type DatabaseConfig struct {
	SQLiteDSN string
}

type StartupConfig struct {
	Server   ServerConfig
	Database DatabaseConfig
}

func LoadStartupFromEnv() (StartupConfig, error) {
	return loadStartupFromLookupEnv(os.LookupEnv)
}

func loadStartupFromLookupEnv(lookup func(string) (string, bool)) (StartupConfig, error) {
	cfg := StartupConfig{
		Server: ServerConfig{
			ListenAddr: readOptionalEnv(lookup, EnvListenAddr, DefaultListenAddr),
		},
		Database: DatabaseConfig{
			SQLiteDSN: readOptionalEnv(lookup, EnvSQLiteDSN, DefaultSQLiteDSN),
		},
	}

	return cfg, nil
}

func LoadAdminTokenFromEnv() (string, error) {
	return loadAdminTokenFromLookupEnv(os.LookupEnv)
}

func loadAdminTokenFromLookupEnv(lookup func(string) (string, bool)) (string, error) {
	token := strings.TrimSpace(readRequiredEnv(lookup, EnvAdminToken))
	if token == "" {
		return "", fmt.Errorf("%s is required", EnvAdminToken)
	}

	return token, nil
}

func readOptionalEnv(lookup func(string) (string, bool), key string, defaultValue string) string {
	value, ok := lookup(key)
	if !ok {
		return defaultValue
	}

	value = strings.TrimSpace(value)
	if value == "" {
		return defaultValue
	}

	return value
}

func readRequiredEnv(lookup func(string) (string, bool), key string) string {
	value, ok := lookup(key)
	if !ok {
		return ""
	}

	return value
}