package httpapp

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

// parseSizeString parses a human-readable size string to bytes
func (a *App) parseSizeString(sizeStr string) (uint64, error) {
	sizeStr = strings.TrimSpace(strings.ToUpper(sizeStr))
	if sizeStr == "" {
		return 0, fmt.Errorf("size cannot be empty")
	}

	// Extract number and unit
	var numStr string
	var unit string

	for i, r := range sizeStr {
		if r >= '0' && r <= '9' {
			numStr += string(r)
		} else {
			unit = sizeStr[i:]
			break
		}
	}

	if numStr == "" {
		return 0, fmt.Errorf("invalid size format: no number found")
	}

	num, err := strconv.ParseUint(numStr, 10, 64)
	if err != nil {
		return 0, fmt.Errorf("invalid size number: %w", err)
	}

	// Convert to bytes based on unit
	multiplier := uint64(1)
	switch unit {
	case "":
		multiplier = 1
	case "K", "KB":
		multiplier = 1024
	case "M", "MB":
		multiplier = 1024 * 1024
	case "G", "GB":
		multiplier = 1024 * 1024 * 1024
	case "T", "TB":
		multiplier = 1024 * 1024 * 1024 * 1024
	case "P", "PB":
		multiplier = 1024 * 1024 * 1024 * 1024 * 1024
	default:
		return 0, fmt.Errorf("invalid size unit: %s (allowed: K, M, G, T, P)", unit)
	}

	return num * multiplier, nil
}