#include <Windows.h>
#include <cstdio>
#include <cstring>

static void printHelp();
static bool copyDirRecursively(
    const char *srcPath, const char *dstPath
);

int main(int argc, char *argv[]) {
    /*
    printf("argc=%d\n", argc);
    for (int i = 0; i < argc; ++i) {
        printf("argv[%d]=\"%s\" (length=%d)\n", i, argv[i], strlen(argv[i]));
    }
    */
    if (argc < 3) {
        printHelp();
        return 1;
    }
    DWORD attr = GetFileAttributes(argv[1]);
    if (attr == INVALID_FILE_ATTRIBUTES) {
        printf("Illegal source directory.\n");
        return (-1);
    } else if ((attr & FILE_ATTRIBUTE_DIRECTORY) == 0) {
        printf("Source is not a directory.\n");
        return (-1);
    }

    attr = GetFileAttributes(argv[2]);
    if (attr == INVALID_FILE_ATTRIBUTES) {
        printf("Illegal destination directory.\n");
        return (-1);
    } else if ((attr & FILE_ATTRIBUTE_DIRECTORY) == 0) {
        printf("Destination is not a directory.\n");
        return (-1);
    }
    if (!copyDirRecursively(argv[1], argv[2]))
        return (-1);
    return 0;
}

static void printHelp() {
    printf(
        "Copy contents of a directory recursively.\n"
        "Usage:\n"
        "\trcopy sourceDir destinationDir\n"
    );
}

static bool copyDirRecursively(
    const char *srcPath, const char *dstPath
) {
    DWORD attr = GetFileAttributes(srcPath);
    if (
        attr == INVALID_FILE_ATTRIBUTES ||
        (attr & FILE_ATTRIBUTE_DIRECTORY) == 0
    ) {
        return false;
    }

    attr = GetFileAttributes(dstPath);
    if (
        attr == INVALID_FILE_ATTRIBUTES ||
        (attr & FILE_ATTRIBUTE_DIRECTORY) == 0
    ) {
        return false;
    }

    char srcFile[MAX_PATH];
    strcpy(srcFile, srcPath);
    size_t len = strlen(srcFile);
    if (len == 0)
        return false;
    if (srcFile[len-1] != '\\' && srcFile[len-1] != '/')
        strcat(srcFile, "\\");
    int srcLen = strlen(srcFile);
    
    char pattern[MAX_PATH];
    strcpy(pattern, srcFile);
    strcat(pattern, "*");

    char dstFile[MAX_PATH];
    strcpy(dstFile, dstPath);
    len = strlen(dstFile);
    if (len == 0)
        return false;
    if (dstFile[len-1] != '\\' && dstFile[len-1] != '/')
        strcat(dstFile, "\\");
        
    size_t dstLen = strlen(dstFile);

    WIN32_FIND_DATA findData;
    HANDLE h;
    h = FindFirstFile(pattern, &findData);
    while (h != INVALID_HANDLE_VALUE) {
        if (
            strcmp(findData.cFileName, "..") != 0 &&
            strcmp(findData.cFileName, ".") != 0
        ) {
            strcpy(srcFile + srcLen, findData.cFileName);
            strcpy(dstFile + dstLen, findData.cFileName);
            printf("%s -> %s\n", srcFile, dstFile);

            if (
                (findData.dwFileAttributes & FILE_ATTRIBUTE_DIRECTORY) != 0
            )
            {
                // Make subdirectory in destination directory
                if (!CreateDirectory(
                    dstFile, NULL
                )) {
                    DWORD err = GetLastError();
                    if (err != 0 && err != ERROR_ALREADY_EXISTS) {
                        printf("Cannot create a directory, err=%d\n", err);
                        return false;
                    }
                }
                if (!copyDirRecursively(
                    srcFile, dstFile
                )) {
                    printf(
                        "Failed to copy subdirectory %s\n",
                        findData.cFileName
                    );
                    return false;
                }
            } else {
                // Normal file
                if (!CopyFile(srcFile, dstFile, FALSE)) {
                    printf(
                        "Cannot copy the file %s\n",                
                        findData.cFileName
                    );
                    return false;
                }
            }
        }

        if (!FindNextFile(h, &findData)) 
            break;
    }
    FindClose(h);
        
    return true;
}