package main

import (
    "crypto/sha256"
    "encoding/hex"
    "fmt"
    "io"
    "os"
    "path/filepath"
    "strings"
    "os/exec"

    "github.com/spf13/viper"
)

const (
    ARCH_X86_64  = "x86_64"
    ARCH_RISCV64 = "riscv64"
    ARCH_I386    = "i386"
    ARCH_AARCH64 = "aarch64"
    ARCH_NOARCH  = "noarch"
    ARCH_SRC     = "src"
)

type Repository struct {
    BasePath string
}

func NewRepository() *Repository {
    return &Repository{
        BasePath: viper.GetString("repository.path"),
    }
}

// ProcessPackage обрабатывает загруженный пакет
func (r *Repository) ProcessPackage(arch, filename string, body io.Reader) error {
    // Преобразуем body к io.ReadSeeker для возможности использовать Seek
    readSeeker, ok := body.(io.ReadSeeker)
    if !ok {
        logger.Errorf("Failed to cast body to io.ReadSeeker for file %s", filename)
        return fmt.Errorf("failed to cast body to io.ReadSeeker")
    }

    // Вычисляем контрольную сумму загруженного файла
    hash := sha256.New()
    if _, err := io.Copy(hash, readSeeker); err != nil {
        logger.Errorf("Error computing checksum for file %s: %v", filename, err)
        return err
    }
    checksum := hex.EncodeToString(hash.Sum(nil))

    // Возвращаемся к началу файла для записи
    if _, err := readSeeker.Seek(0, 0); err != nil {
        logger.Errorf("Error seeking to the beginning of file %s: %v", filename, err)
        return err
    }

    // Проверяем, существует ли файл с такой контрольной суммой
    if r.fileExistsWithChecksum(arch, filename, checksum) {
        logger.Infof("File %s already exists with the same checksum, skipping upload.", filename)
        return nil
    }

    // Сохраняем пакет
    if err := r.SavePackage(arch, filename, readSeeker); err != nil {
        logger.Errorf("Error saving package %s: %v", filename, err)
        return err
    }

    return nil
}

func (r *Repository) SavePackage(arch, name string, body io.Reader) error {
    logger.Infof("Saving package %s for architecture %s", name, arch)
    dir := filepath.Join(r.BasePath, arch)
    if err := os.MkdirAll(dir, 0755); err != nil {
        logger.Errorf("Failed to create directory %s: %v", dir, err)
        return err
    }
    filePath := filepath.Join(dir, name)
    file, err := os.Create(filePath)
    if err != nil {
        logger.Errorf("Failed to create file %s: %v", filePath, err)
        return err
    }
    defer file.Close()
    _, err = io.Copy(file, body)
    if err != nil {
        logger.Errorf("Failed to copy file content to %s: %v", filePath, err)
        return err
    }

    // Generate metadata
    cmd := exec.Command("genhdlist2", "--update", "--root", dir)
    logger.Infof("Generating metadata for directory %s", dir)
    if err := cmd.Run(); err != nil {
        logger.Errorf("Failed to generate metadata: %v", err)
        return fmt.Errorf("failed to generate metadata: %w", err)
    }
    logger.Infof("Package %s saved successfully for architecture %s", name, arch)
    return nil
}

func (r *Repository) fileExistsWithChecksum(arch, filename, checksum string) bool {
    filePath := filepath.Join(r.BasePath, arch, filename)
    file, err := os.Open(filePath)
    if err != nil {
        if os.IsNotExist(err) {
            return false
        }
        logger.Errorf("Error opening file %s: %v", filePath, err)
        return false
    }
    defer file.Close()

    hash := sha256.New()
    if _, err := io.Copy(hash, file); err != nil {
        logger.Errorf("Error computing checksum for file %s: %v", filePath, err)
        return false
    }
    existingChecksum := hex.EncodeToString(hash.Sum(nil))

    return existingChecksum == checksum
}

func (r *Repository) GetArch(arch string) string {
    switch strings.ToLower(arch) {
    case ARCH_X86_64:
        return ARCH_X86_64
    case ARCH_RISCV64:
        return ARCH_RISCV64
    case ARCH_I386:
        return ARCH_I386
    case ARCH_AARCH64:
        return ARCH_AARCH64
    case ARCH_NOARCH:
        return ARCH_NOARCH
    case ARCH_SRC:
        return ARCH_SRC
    default:
        return ""
    }
}