package main

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

const (
	defaultAddr     = "127.0.0.1:7777"
	defaultMaxSize  = 100 << 20 // 100 MiB
	tokenHeader     = "X-Open-Token"
	fileNameHeader  = "X-Open-Filename"
	pathHeaderField = "X-Open-Host-Path"
)

func envAddr() string {
	if v := os.Getenv("OPEN_PROXY_ADDR"); v != "" {
		return v
	}
	return defaultAddr
}

func envToken() (string, error) {
	if v := os.Getenv("OPEN_PROXY_TOKEN"); v != "" {
		return v, nil
	}

	path := os.Getenv("OPEN_PROXY_TOKEN_FILE")
	if path == "" {
		return "", nil
	}

	b, err := os.ReadFile(path)
	if err != nil {
		return "", fmt.Errorf("read OPEN_PROXY_TOKEN_FILE %q: %w", path, err)
	}

	token := strings.TrimRight(string(b), "\r\n")
	if token == "" {
		return "", fmt.Errorf("OPEN_PROXY_TOKEN_FILE %q is empty", path)
	}
	return token, nil
}

func envMaxSize() int64 {
	if v := os.Getenv("OPEN_PROXY_MAXSIZE"); v != "" {
		if n, err := strconv.ParseInt(v, 10, 64); err == nil && n > 0 {
			return n
		}
	}
	return defaultMaxSize
}