/*
** wasi.cpp
**
** This file is part of mkxp.
**
** Copyright (C) 2013 - 2021 Amaryllis Kulla <ancurio@mapleshrine.eu>
**
** mkxp is free software: you can redistribute it and/or modify
** it under the terms of the GNU General Public License as published by
** the Free Software Foundation, either version 2 of the License, or
** (at your option) any later version.
**
** mkxp is distributed in the hope that it will be useful,
** but WITHOUT ANY WARRANTY; without even the implied warranty of
** MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
** GNU General Public License for more details.
**
** You should have received a copy of the GNU General Public License
** along with mkxp.  If not, see <http://www.gnu.org/licenses/>.
*/

#include <cstring>
#include <algorithm>
#include <random>
#include <sstream>
#include <mkxp-sandbox-ruby.h>
#include "filesystem.h"
#include "core.h"
#include "wasi.h"

//#define WASI_DEBUG(...) mkxp_retro::log_printf(RETRO_LOG_INFO, __VA_ARGS__)
#define WASI_DEBUG(...)

#define WASM_MEM(address) ((void *)&wasi->ruby->w2c_memory.data[address])

static inline size_t strlen_safe(const char *str, size_t max_length) {
    const char *ptr = (const char *)std::memchr(str, 0, max_length);
    return ptr == nullptr ? max_length : ptr - str;
}

struct fs_dir *wasi_file_entry::dir_handle() {
    return (struct fs_dir *)handle;
}

struct FileSystem::File *wasi_file_entry::file_handle() {
    return (struct FileSystem::File *)handle;
}

wasi_t::w2c_wasi__snapshot__preview1(std::shared_ptr<struct w2c_ruby> ruby) : ruby(ruby) {
    // Initialize WASI file descriptor table
    fdtable.push_back({.type = wasi_fd_type::STDIN});
    fdtable.push_back({.type = wasi_fd_type::STDOUT});
    fdtable.push_back({.type = wasi_fd_type::STDERR});
    fdtable.push_back({.type = wasi_fd_type::FS, .handle = new fs_dir {.root = nullptr, .path = std::string("/game"), .writable = true}});
    fdtable.push_back({.type = wasi_fd_type::FS, .handle = new fs_dir {.root = nullptr, .path = std::string("/save"), .writable = true}});
    fdtable.push_back({.type = wasi_fd_type::FS, .handle = new fs_dir {.root = nullptr, .path = std::string("/dist"), .writable = false}});
}

wasi_t::~w2c_wasi__snapshot__preview1() {
    // Close all of the open WASI file descriptors
    for (size_t i = fdtable.size(); i > 0;) {
        deallocate_file_descriptor(--i);
    }
}

struct fs_enumerate_data {
    wasi_t *wasi;
    u32 fd;
    usize original_buf;
    usize buf;
    u32 buf_len;
    u64 initial_cookie;
    u64 cookie;
    usize result;
};

u32 wasi_t::allocate_file_descriptor(enum wasi_fd_type type, void *handle) {
    if (vacant_fds.empty()) {
        u32 fd = fdtable.size();
        fdtable.push_back({.type = type, .handle = handle});
        return fd;
    } else {
        u32 fd = vacant_fds.back();
        vacant_fds.pop_back();
        return fd;
    }
}

void wasi_t::deallocate_file_descriptor(u32 fd) {
    if (fdtable[fd].handle != nullptr) {
        switch (fdtable[fd].type) {
            case wasi_fd_type::FS:
            case wasi_fd_type::FSDIR:
                delete fdtable[fd].dir_handle();
                break;
            case wasi_fd_type::FSFILE:
                delete fdtable[fd].file_handle();
                break;
            default:
                break;
        }
    }

    if (!fdtable.empty() && fd == fdtable.size() - 1) {
        fdtable.pop_back();
    } else {
        fdtable[fd] = {.type = wasi_fd_type::VACANT, .handle = nullptr};
        vacant_fds.push_back(fd);
    }
}

extern "C" u32 w2c_wasi__snapshot__preview1_args_get(wasi_t *wasi, usize argv, usize argv_buf) {
    WASI_DEBUG("args_get()\n");
    return WASI_ESUCCESS;
}

extern "C" u32 w2c_wasi__snapshot__preview1_args_sizes_get(wasi_t *wasi, usize argc, usize argv_buf_size) {
    WASI_DEBUG("args_sizes_get(0x%08x, 0x%08x)\n", argc, argv_buf_size);
    WASM_SET(u32, argc, 0);
    WASM_SET(u32, argv_buf_size, 0);
    return WASI_ESUCCESS;
}

extern "C" u32 w2c_wasi__snapshot__preview1_clock_res_get(wasi_t *wasi, u32 id, usize result) {
    WASI_DEBUG("clock_res_get(%u)\n", id);
    WASM_SET(u64, result, 1000L);
    return WASI_ESUCCESS;
}

extern "C" u32 w2c_wasi__snapshot__preview1_clock_time_get(wasi_t *wasi, u32 id, u64 precision, usize result) {
    WASI_DEBUG("clock_time_get(%u, %lu)\n", id, precision);
    WASM_SET(u64, result, mkxp_retro::perf.get_time_usec != nullptr ? mkxp_retro::perf.get_time_usec() * 1000L : 0);
    return WASI_ESUCCESS;
}

extern "C" u32 w2c_wasi__snapshot__preview1_environ_get(wasi_t *wasi, usize env, usize env_buf) {
    WASI_DEBUG("environ_get(0x%08x, 0x%08x)\n", env, env_buf);
    return WASI_ESUCCESS;
}

extern "C" u32 w2c_wasi__snapshot__preview1_environ_sizes_get(wasi_t *wasi, usize env_size, usize env_buf_size) {
    WASI_DEBUG("environ_sizes_get()\n");
    WASM_SET(u32, env_size, 0);
    WASM_SET(u32, env_buf_size, 0);
    return WASI_ESUCCESS;
}

extern "C" u32 w2c_wasi__snapshot__preview1_fd_advise(wasi_t *wasi, u32 fd, u64 offset, u64 len, u32 advice) {
    WASI_DEBUG("fd_advise(%u, %lu, %lu, 0x%08x)\n", fd, offset, len, advice);
    return WASI_ENOSYS;
}

extern "C" u32 w2c_wasi__snapshot__preview1_fd_close(wasi_t *wasi, u32 fd) {
    WASI_DEBUG("fd_close(%u)\n", fd);

    if (fd >= wasi->fdtable.size()) {
        return WASI_EBADF;
    }

    switch (wasi->fdtable[fd].type) {
        case wasi_fd_type::VACANT:
            return WASI_EBADF;

        case wasi_fd_type::STDIN:
        case wasi_fd_type::STDOUT:
        case wasi_fd_type::STDERR:
        case wasi_fd_type::FS:

        case wasi_fd_type::FSDIR:
        case wasi_fd_type::FSFILE:
            wasi->deallocate_file_descriptor(fd);
            return WASI_ESUCCESS;
    }

    return WASI_EBADF;
}

extern "C" u32 w2c_wasi__snapshot__preview1_fd_datasync(wasi_t *wasi, u32 fd) {
    WASI_DEBUG("fd_datasync(%u)\n", fd);
    return WASI_ENOSYS;
}

extern "C" u32 w2c_wasi__snapshot__preview1_fd_fdstat_get(wasi_t *wasi, u32 fd, usize result) {
    WASI_DEBUG("fd_fdstat_get(%u)\n", fd);

    if (fd >= wasi->fdtable.size()) {
        return WASI_EBADF;
    }

    switch (wasi->fdtable[fd].type) {
        case wasi_fd_type::VACANT:
            return WASI_EBADF;

        case wasi_fd_type::STDIN:
        case wasi_fd_type::STDOUT:
        case wasi_fd_type::STDERR:
        case wasi_fd_type::FSFILE:
            WASM_SET(u8, result, WASI_IFCHR); // fs_filetype
            WASM_SET(u16, result + 2, 0); // fs_flags
            WASM_SET(u64, result + 8, WASI_FD_READ | WASI_FD_WRITE | WASI_FD_FILESTAT_GET); // fs_rights_base
            WASM_SET(u64, result + 16, 0); // fs_rights_inheriting
            return WASI_ESUCCESS;

        case wasi_fd_type::FS:
        case wasi_fd_type::FSDIR:
            WASM_SET(u8, result, WASI_IFDIR); // fs_filetype
            WASM_SET(u16, result + 2, 0); // fs_flags
            WASM_SET(u64, result + 8, WASI_PATH_OPEN | WASI_FD_READDIR | WASI_PATH_FILESTAT_GET | WASI_FD_FILESTAT_GET); // fs_rights_base
            WASM_SET(u64, result + 16, 0); // fs_rights_inheriting
            return WASI_ESUCCESS;
    }

    return WASI_EBADF;
}

extern "C" u32 w2c_wasi__snapshot__preview1_fd_fdstat_set_flags(wasi_t *wasi, u32 fd, u32 flags) {
    WASI_DEBUG("fd_fdstat_set_flags(%u, %u)\n", fd, flags);

    if (fd >= wasi->fdtable.size()) {
        return WASI_EBADF;
    }

    switch (wasi->fdtable[fd].type) {
        case wasi_fd_type::VACANT:
            return WASI_EBADF;

        case wasi_fd_type::STDIN:
        case wasi_fd_type::STDOUT:
        case wasi_fd_type::STDERR:
        case wasi_fd_type::FS:
        case wasi_fd_type::FSDIR:
        case wasi_fd_type::FSFILE:
            return WASI_ESUCCESS;
    }

    return WASI_EBADF;
}

extern "C" u32 w2c_wasi__snapshot__preview1_fd_filestat_get(wasi_t *wasi, u32 fd, usize result) {
    WASI_DEBUG("fd_filestat_get(%u)\n", fd);

    if (fd >= wasi->fdtable.size()) {
        return WASI_EBADF;
    }

    switch (wasi->fdtable[fd].type) {
        case wasi_fd_type::VACANT:
            return WASI_EBADF;

        case wasi_fd_type::STDIN:
        case wasi_fd_type::STDOUT:
        case wasi_fd_type::STDERR:
            WASM_SET(u64, result, fd); // dev
            WASM_SET(u64, result + 8, 0); // ino
            WASM_SET(u8, result + 16, WASI_IFCHR); // filetype
            WASM_SET(u32, result + 24, 1); // nlink
            WASM_SET(u64, result + 32, 0); // size
            WASM_SET(u64, result + 40, 0); // atim
            WASM_SET(u64, result + 48, 0); // mtim
            WASM_SET(u64, result + 56, 0); // ctim
            return WASI_ESUCCESS;

        case wasi_fd_type::FS:
        case wasi_fd_type::FSDIR:
            {
                PHYSFS_Stat stat;
                if (!PHYSFS_stat(wasi->fdtable[fd].dir_handle()->path.c_str(), &stat)) {
                    return WASI_ENOENT;
                }
                if (stat.filetype != PHYSFS_FILETYPE_DIRECTORY) {
                    return WASI_EIO;
                }
                WASM_SET(u64, result, fd); // dev
                WASM_SET(u64, result + 8, 0); // ino // TODO: generate a pseudorandom inode number
                WASM_SET(u8, result + 16, WASI_IFDIR); // filetype
                WASM_SET(u32, result + 24, 1); // nlink
                WASM_SET(u64, result + 32, stat.filesize); // size
                WASM_SET(u64, result + 40, stat.accesstime * 1000000000L); // atim
                WASM_SET(u64, result + 48, stat.modtime * 1000000000L); // mtim
                WASM_SET(u64, result + 56, stat.createtime * 1000000000L); // ctim
                return WASI_ESUCCESS;
            }

        case wasi_fd_type::FSFILE:
            {
                PHYSFS_Stat stat;
                if (!PHYSFS_stat(wasi->fdtable[fd].file_handle()->path(), &stat)) {
                    return WASI_ENOENT;
                }
                if (stat.filetype != PHYSFS_FILETYPE_REGULAR) {
                    return WASI_EIO;
                }
                WASM_SET(u64, result, fd); // dev
                WASM_SET(u64, result + 8, 0); // ino // TODO: generate a pseudorandom inode number
                WASM_SET(u8, result + 16, WASI_IFREG); // filetype
                WASM_SET(u32, result + 24, 1); // nlink
                WASM_SET(u64, result + 32, stat.filesize); // size
                WASM_SET(u64, result + 40, stat.accesstime * 1000000000L); // atim
                WASM_SET(u64, result + 48, stat.modtime * 1000000000L); // mtim
                WASM_SET(u64, result + 56, stat.createtime * 1000000000L); // ctim
                return WASI_ESUCCESS;
            }
    }

    return WASI_EBADF;
}

extern "C" u32 w2c_wasi__snapshot__preview1_fd_filestat_set_size(wasi_t *wasi, u32 fd, u64 size) {
    WASI_DEBUG("fd_filestat_set_size(%u, %lu)\n", fd, size);

    if (fd >= wasi->fdtable.size()) {
        return WASI_EBADF;
    }

    switch (wasi->fdtable[fd].type) {
        case wasi_fd_type::STDIN:
        case wasi_fd_type::STDOUT:
        case wasi_fd_type::STDERR:
            return WASI_EINVAL;

        default:
            return WASI_ENOSYS;
    }

    return WASI_EBADF;
}

extern "C" u32 w2c_wasi__snapshot__preview1_fd_pread(wasi_t *wasi, u32 fd, usize iovs, u32 iovs_len, u64 offset, usize result) {
    WASI_DEBUG("fd_pread(%u, 0x%08x (%u), %lu)\n", fd, iovs, iovs_len, offset);
    return WASI_ENOSYS;
}

extern "C" u32 w2c_wasi__snapshot__preview1_fd_prestat_dir_name(wasi_t *wasi, u32 fd, usize path, u32 path_len) {
    WASI_DEBUG("fd_prestat_dir_name(%u, 0x%x (%u))\n", fd, path, path_len);

    if (fd >= wasi->fdtable.size()) {
        return WASI_EBADF;
    }

    switch (wasi->fdtable[fd].type) {
        case wasi_fd_type::VACANT:
            return WASI_EBADF;

        case wasi_fd_type::FS:
            std::strncpy((char *)WASM_MEM(path), wasi->fdtable[fd].dir_handle()->path.c_str(), path_len);
            return WASI_ESUCCESS;

        case wasi_fd_type::STDIN:
        case wasi_fd_type::STDOUT:
        case wasi_fd_type::STDERR:
        case wasi_fd_type::FSDIR:
        case wasi_fd_type::FSFILE:
            return WASI_EINVAL;
    }

    return WASI_EBADF;
}

extern "C" u32 w2c_wasi__snapshot__preview1_fd_prestat_get(wasi_t *wasi, u32 fd, usize result) {
    WASI_DEBUG("fd_prestat_get(%u)\n", fd);

    if (fd >= wasi->fdtable.size()) {
        return WASI_EBADF;
    }

    switch (wasi->fdtable[fd].type) {
        case wasi_fd_type::VACANT:
            return WASI_EBADF;

        case wasi_fd_type::FS:
            WASM_SET(u32, result, 0);
            WASM_SET(u32, result + 4, wasi->fdtable[fd].dir_handle()->path.length());
            return WASI_ESUCCESS;

        case wasi_fd_type::STDIN:
        case wasi_fd_type::STDOUT:
        case wasi_fd_type::STDERR:
        case wasi_fd_type::FSDIR:
        case wasi_fd_type::FSFILE:
            return WASI_EINVAL;
    }

    return WASI_EBADF;
}

extern "C" u32 w2c_wasi__snapshot__preview1_fd_pwrite(wasi_t *wasi, u32 fd, usize iovs, u32 iovs_len, u64 offset, usize result) {
    WASI_DEBUG("fd_pwrite(%u, 0x%08x (%u), %lu)\n", fd, iovs, iovs_len, offset);
    return WASI_ENOSYS;
}

extern "C" u32 w2c_wasi__snapshot__preview1_fd_read(wasi_t *wasi, u32 fd, usize iovs, u32 iovs_len, usize result) {
    WASI_DEBUG("fd_read(%u, 0x%08x (%u))\n", fd, iovs, iovs_len);

    if (fd >= wasi->fdtable.size()) {
        return WASI_EBADF;
    }

    switch (wasi->fdtable[fd].type) {
        case wasi_fd_type::VACANT:
            return WASI_EBADF;

        case wasi_fd_type::STDIN:
        case wasi_fd_type::STDOUT:
        case wasi_fd_type::STDERR:
            WASM_SET(u32, result, 0);
            return WASI_ESUCCESS;

        case wasi_fd_type::FS:
        case wasi_fd_type::FSDIR:
            return WASI_EINVAL;

        case wasi_fd_type::FSFILE:
            {
                u32 size = 0;
                while (iovs_len > 0) {
                    PHYSFS_sint64 n = PHYSFS_readBytes(wasi->fdtable[fd].file_handle()->get(), WASM_MEM(WASM_GET(u32, iovs)), WASM_GET(u32, iovs + 4));
                    if (n < 0) return WASI_EIO;
                    size += n;
                    iovs += 8;
                    --iovs_len;
                }
                WASM_SET(u32, result, size);
                return WASI_ESUCCESS;
            }
    }

    return WASI_EBADF;
}

extern "C" u32 w2c_wasi__snapshot__preview1_fd_readdir(wasi_t *wasi, u32 fd, usize buf, u32 buf_len, u64 cookie, usize result) {
    WASI_DEBUG("fd_readdir(%u, 0x%08x (%u), %lu)\n", fd, buf, buf_len, cookie);

    if (fd >= wasi->fdtable.size()) {
        return WASI_EBADF;
    }

    switch (wasi->fdtable[fd].type) {
        case wasi_fd_type::VACANT:
            return WASI_EBADF;

        case wasi_fd_type::STDIN:
        case wasi_fd_type::STDOUT:
        case wasi_fd_type::STDERR:
        case wasi_fd_type::FSFILE:
            return WASI_EINVAL;

        case wasi_fd_type::FS:
        case wasi_fd_type::FSDIR:
            {
                struct fs_enumerate_data edata = {
                    .wasi = wasi,
                    .fd = fd,
                    .original_buf = buf,
                    .buf = buf,
                    .buf_len = buf_len,
                    .initial_cookie = cookie,
                    .cookie = 0,
                    .result = result,
                };
                bool success = PHYSFS_enumerate(
                    wasi->fdtable[fd].dir_handle()->path.c_str(),
                    [](void *data, const char *path, const char *filename) {
                        struct fs_enumerate_data *edata = (struct fs_enumerate_data *)data;
                        wasi_t *wasi = edata->wasi;

                        PHYSFS_Stat stat;
                        if (!PHYSFS_stat(edata->wasi->fdtable[edata->fd].dir_handle()->path.c_str(), &stat)) {
                            return PHYSFS_ENUM_OK;
                        }
                        if (stat.filetype != PHYSFS_FILETYPE_DIRECTORY && stat.filetype != PHYSFS_FILETYPE_REGULAR) {
                            return PHYSFS_ENUM_OK;
                        }

                        if (edata->cookie++ < edata->initial_cookie) {
                            return PHYSFS_ENUM_OK;
                        }

                        if (edata->buf - edata->original_buf + 8 > edata->buf_len) {
                            return PHYSFS_ENUM_STOP;
                        }
                        WASM_SET(u64, edata->buf, edata->cookie);
                        edata->buf += 8;

                        if (edata->buf - edata->original_buf + 8 > edata->buf_len) {
                            return PHYSFS_ENUM_STOP;
                        }
                        WASM_SET(u64, edata->buf, 0); // TODO: generate a pseudorandom inode number
                        edata->buf += 8;

                        if (edata->buf - edata->original_buf + 4 > edata->buf_len) {
                            return PHYSFS_ENUM_STOP;
                        }
                        WASM_SET(u32, edata->buf, std::strlen(filename));
                        edata->buf += 4;

                        if (edata->buf - edata->original_buf + 4 > edata->buf_len) {
                            return PHYSFS_ENUM_STOP;
                        }
                        WASM_SET(u8, edata->buf, stat.filetype);
                        edata->buf += 4;

                        u32 len = std::min(std::strlen(filename), (size_t)(edata->original_buf + edata->buf_len - edata->buf));
                        std::memcpy(WASM_MEM(edata->buf), filename, std::strlen(filename));
                        edata->buf += len;
                        return PHYSFS_ENUM_OK;
                    },
                    (void *)&edata
                );
                if (success) {
                    WASM_SET(u32, result, edata.buf - edata.original_buf);
                    return WASI_ESUCCESS;
                }
                return success ? WASI_ESUCCESS : WASI_ENOENT;
            }
    }

    return WASI_EBADF;
}

extern "C" u32 w2c_wasi__snapshot__preview1_fd_renumber(wasi_t *wasi, u32 fd, u32 to) {
    WASI_DEBUG("fd_renumber(%u, %u)\n", fd, to);

    if (fd >= wasi->fdtable.size()) {
        return WASI_EBADF;
    }

    switch (wasi->fdtable[fd].type) {
        case wasi_fd_type::VACANT:
            return WASI_EBADF;

        case wasi_fd_type::STDIN:
        case wasi_fd_type::STDOUT:
        case wasi_fd_type::STDERR:
        case wasi_fd_type::FS:
            return WASI_EINVAL;

        case wasi_fd_type::FSDIR:
        case wasi_fd_type::FSFILE:
            break;
    }

    if (fd == to) {
        return WASI_ESUCCESS;
    }

    if (to >= wasi->fdtable.size()) return WASI_EBADF;

    switch (wasi->fdtable[to].type) {
        case wasi_fd_type::VACANT:
            return WASI_EBADF;

        case wasi_fd_type::STDIN:
        case wasi_fd_type::STDOUT:
        case wasi_fd_type::STDERR:
        case wasi_fd_type::FS:
            return WASI_EINVAL;

        case wasi_fd_type::FSDIR:
        case wasi_fd_type::FSFILE:
            wasi->deallocate_file_descriptor(to);
            if (to == wasi->fdtable.size()) {
                wasi->fdtable.push_back(wasi->fdtable[fd]);
            } else {
                wasi->fdtable[to] = wasi->fdtable[fd];
            }
            if (!wasi->fdtable.empty() && fd == wasi->fdtable.size() - 1) {
                wasi->fdtable.pop_back();
            } else {
                wasi->fdtable[fd] = {.type = wasi_fd_type::VACANT, .handle = nullptr};
                wasi->vacant_fds.push_back(fd);
            }
            return WASI_ESUCCESS;
    }

    return WASI_EBADF;
}

extern "C" u32 w2c_wasi__snapshot__preview1_fd_seek(wasi_t *wasi, u32 fd, u64 offset, u32 whence, usize result) {
    WASI_DEBUG("fd_seek(%u, %lu, %u)\n", fd, offset, whence);
    return WASI_ENOSYS;
}

extern "C" u32 w2c_wasi__snapshot__preview1_fd_sync(wasi_t *wasi, u32 fd) {
    WASI_DEBUG("fd_sync(%u)\n", fd);
    return WASI_ENOSYS;
}

extern "C" u32 w2c_wasi__snapshot__preview1_fd_tell(wasi_t *wasi, u32 fd, usize result) {
    WASI_DEBUG("fd_tell(%u)\n", fd);

    if (fd >= wasi->fdtable.size()) {
        return WASI_EBADF;
    }

    switch (wasi->fdtable[fd].type) {
        case wasi_fd_type::VACANT:
            return WASI_EBADF;

        case wasi_fd_type::STDIN:
        case wasi_fd_type::STDOUT:
        case wasi_fd_type::STDERR:
        case wasi_fd_type::FS:
        case wasi_fd_type::FSDIR:
            return WASI_EINVAL;

        case wasi_fd_type::FSFILE:
            WASM_SET(u64, result, PHYSFS_tell(wasi->fdtable[fd].file_handle()->get()));
            return WASI_ESUCCESS;
    }

    return WASI_EBADF;
}

extern "C" u32 w2c_wasi__snapshot__preview1_fd_write(wasi_t *wasi, u32 fd, usize iovs, u32 iovs_len, usize result) {
    WASI_DEBUG("fd_write(%u, 0x%08x (%u))\n", fd, iovs, iovs_len);

    if (fd >= wasi->fdtable.size()) {
        return WASI_EBADF;
    }

    switch (wasi->fdtable[fd].type) {
        case wasi_fd_type::VACANT:
            return WASI_EBADF;

        case wasi_fd_type::STDIN:
            WASM_SET(u32, result, 0);
            return WASI_ESUCCESS;

        case wasi_fd_type::STDOUT:
        case wasi_fd_type::STDERR:
            {
                u32 size = 0;
                std::string buf;
                while (iovs_len > 0) {
                    buf.append((const char *)WASM_MEM(WASM_GET(u32, iovs)), strlen_safe((const char *)WASM_MEM(WASM_GET(u32, iovs)), WASM_GET(u32, iovs + 4)));
                    size += WASM_GET(u32, iovs + 4);
                    iovs += 8;
                    --iovs_len;
                }
                std::string line;
                std::istringstream stream(buf);
                while (std::getline(stream, line)) {
                    mkxp_retro::log_printf(wasi->fdtable[fd].type == wasi_fd_type::STDOUT ? RETRO_LOG_INFO : RETRO_LOG_ERROR, "%s\n", line.c_str());
                }
                WASM_SET(u32, result, size);
                return WASI_ESUCCESS;
            }

        case wasi_fd_type::FS:
        case wasi_fd_type::FSDIR:
            return WASI_EINVAL;

        case wasi_fd_type::FSFILE:
            {
                if (!wasi->fdtable[fd].file_handle()->is_write_open()) {
                    return WASI_EROFS;
                }
                u32 size = 0;
                while (iovs_len > 0) {
                    PHYSFS_sint64 n = PHYSFS_writeBytes(wasi->fdtable[fd].file_handle()->get_write(), WASM_MEM(WASM_GET(u32, iovs)), WASM_GET(u32, iovs + 4));
                    if (n >= 0) {
                        size += n;
                    }
                    iovs += 8;
                    --iovs_len;
                }
                WASM_SET(u32, result, size);
                return WASI_ESUCCESS;
            }
    }

    return WASI_EBADF;
}

extern "C" u32 w2c_wasi__snapshot__preview1_path_create_directory(wasi_t *wasi, u32 fd, usize path, u32 path_len) {
    WASI_DEBUG("path_create_directory(%u, \"%.*s\")\n", fd, path_len, (char *)WASM_MEM(path));
    return WASI_ENOSYS;
}

extern "C" u32 w2c_wasi__snapshot__preview1_path_filestat_get(wasi_t *wasi, u32 fd, u32 flags, usize path, u32 path_len, usize result) {
    WASI_DEBUG("path_filestat_get(%u, %u, \"%.*s\")\n", fd, flags, path_len, (char *)WASM_MEM(path));

    if (fd >= wasi->fdtable.size()) {
        return WASI_EBADF;
    }

    switch (wasi->fdtable[fd].type) {
        case wasi_fd_type::VACANT:
            return WASI_EBADF;

        case wasi_fd_type::STDIN:
        case wasi_fd_type::STDOUT:
        case wasi_fd_type::STDERR:
        case wasi_fd_type::FSFILE:
            return WASI_EINVAL;

        case wasi_fd_type::FS:
        case wasi_fd_type::FSDIR:
            {
                PHYSFS_Stat stat;
                std::string new_path(wasi->fdtable[fd].dir_handle()->path);
                new_path.push_back('/');
                new_path.append((const char *)WASM_MEM(path), strlen_safe((const char *)WASM_MEM(path), path_len));
                new_path = mkxp_retro::fs->normalize(new_path.c_str(), false, true);
                if (std::strncmp(new_path.c_str(), wasi->fdtable[fd].dir_handle()->path.c_str(), wasi->fdtable[fd].dir_handle()->path.length()) != 0) {
                    return WASI_EPERM;
                }

                if (!PHYSFS_stat(new_path.c_str(), &stat)) {
                    return WASI_ENOENT;
                }
                if (stat.filetype != PHYSFS_FILETYPE_DIRECTORY && stat.filetype != PHYSFS_FILETYPE_REGULAR) {
                    return WASI_EIO;
                }

                WASM_SET(u64, result, fd); // dev
                WASM_SET(u64, result + 8, 0); // ino // TODO: generate a pseudorandom inode number
                WASM_SET(u8, result + 16, stat.filetype == PHYSFS_FILETYPE_DIRECTORY ? WASI_IFDIR : WASI_IFREG); // filetype
                WASM_SET(u32, result + 24, 1); // nlink
                WASM_SET(u64, result + 32, stat.filetype); // size
                WASM_SET(u64, result + 40, stat.accesstime * 1000000000L); // atim
                WASM_SET(u64, result + 48, stat.modtime * 1000000000L); // mtim
                WASM_SET(u64, result + 56, stat.createtime * 1000000000L); // ctim
                return WASI_ESUCCESS;
            }
    }

    return WASI_EBADF;
}

extern "C" u32 w2c_wasi__snapshot__preview1_path_filestat_set_times(wasi_t *wasi, u32 fd, u32 flags, usize path, u32 path_len, u64 atim, u64 ntim, u32 fst_flags) {
    WASI_DEBUG("path_filestat_set_times(%u, %u, \"%.*s\", %lu, %lu, %u)\n", fd, flags, path_len, (char *)WASM_MEM(path), atim, ntim, fst_flags);
    return WASI_ENOSYS;
}

extern "C" u32 w2c_wasi__snapshot__preview1_path_link(wasi_t *wasi, u32 old_fd, u32 old_flags, usize old_path, u32 old_path_len, u32 new_fd, usize new_path, u32 new_path_len) {
    WASI_DEBUG("path_link(%u, %u, \"%.*s\", %u, \"%.*s\")\n", old_fd, old_flags, old_path_len, (char *)WASM_MEM(old_path), new_fd, new_path_len, (char *)WASM_MEM(new_path));
    return WASI_ENOSYS;
}

extern "C" u32 w2c_wasi__snapshot__preview1_path_open(wasi_t *wasi, u32 fd, u32 dirflags, usize path, u32 path_len, u32 oflags, u64 fs_base_rights, u64 fs_rights_inheriting, u32 fdflags, usize result) {
    WASI_DEBUG("path_open(%u, %u, \"%.*s\", %u, %lu, %lu, %u)\n", fd, dirflags, path_len, (char *)WASM_MEM(path), oflags, fs_base_rights, fs_rights_inheriting, fdflags);

    if (fd >= wasi->fdtable.size()) {
        return WASI_EBADF;
    }

    switch (wasi->fdtable[fd].type) {
        case wasi_fd_type::VACANT:
            return WASI_EBADF;

        case wasi_fd_type::STDIN:
        case wasi_fd_type::STDOUT:
        case wasi_fd_type::STDERR:
        case wasi_fd_type::FSFILE:
            return WASI_EINVAL;

        case wasi_fd_type::FS:
        case wasi_fd_type::FSDIR:
            {
                PHYSFS_Stat stat;
                std::string new_path(wasi->fdtable[fd].dir_handle()->path);
                new_path.push_back('/');
                new_path.append((const char *)WASM_MEM(path), strlen_safe((const char *)WASM_MEM(path), path_len));
                new_path = mkxp_retro::fs->normalize(new_path.c_str(), false, true);

                // Verify that the path we're opening is a descendant of the directory corresponding to `fd`
                if (std::strncmp(new_path.c_str(), wasi->fdtable[fd].dir_handle()->path.c_str(), wasi->fdtable[fd].dir_handle()->path.length()) != 0) {
                    return WASI_EPERM;
                }

                bool exists = PHYSFS_stat(new_path.c_str(), &stat);

                // Fail if bit 0 of oflags isn't set and the path doesn't exist
                if (!exists && !(oflags & (1 << 0))) {
                    return WASI_ENOENT;
                }

                // Fail if bit 1 of oflags is set and the path exists and isn't a directory
                if (exists && oflags & (1 << 1) && stat.filetype != PHYSFS_FILETYPE_DIRECTORY) {
                    return WASI_ENOTDIR;
                }

                // Fail if bit 2 of oflags is set and the path exists
                if (exists && oflags & (1 << 2)) {
                    return WASI_EEXIST;
                }

                // Fail if the path exists and isn't a regular file or directory (e.g. a device file, named pipe, socket or symbolic link)
                if (exists && (stat.filetype != PHYSFS_FILETYPE_DIRECTORY && stat.filetype != PHYSFS_FILETYPE_REGULAR)) {
                    return WASI_EIO;
                }

                bool truncate = oflags & (1 << 3);
                bool needs_write = !exists || truncate;
                bool writable = wasi->fdtable[fd].dir_handle()->writable;

                // Fail if we need to create a new file or truncate a file in a read-only file system
                if (needs_write && !writable && oflags & (1 << 0)) {
                    return WASI_EROFS;
                }

                if (exists && stat.filetype == PHYSFS_FILETYPE_DIRECTORY) {
                    struct fs_dir *root = wasi->fdtable[fd].dir_handle()->root != nullptr ? wasi->fdtable[fd].dir_handle()->root : wasi->fdtable[fd].dir_handle();
                    struct fs_dir *handle = new fs_dir {.root = root, .path = new_path, .writable = writable};
                    WASM_SET(u32, result, wasi->allocate_file_descriptor(wasi_fd_type::FSDIR, handle));
                } else {
                    const char *write_path_prefix;
                    if (writable) {
                        struct fs_dir *root = wasi->fdtable[fd].dir_handle()->root != nullptr ? wasi->fdtable[fd].dir_handle()->root : wasi->fdtable[fd].dir_handle();
                        write_path_prefix = root->path.c_str();
                    } else {
                        write_path_prefix = nullptr;
                    }

                    struct FileSystem::File *handle = new FileSystem::File(*mkxp_retro::fs, new_path.c_str(), write_path_prefix, truncate, exists);

                    // Check for errors opening the read handle and/or write handle
                    if (!handle->is_open() || (needs_write && writable && !handle->is_write_open())) {
                        PHYSFS_ErrorCode error = handle->get_read_error();
                        if (error == handle->get_read_error()) {
                            error = handle->get_write_error();
                        }
                        delete handle;
                        switch (error) {
                            case PHYSFS_ERR_READ_ONLY:
                            case PHYSFS_ERR_NO_WRITE_DIR:
                                return WASI_EROFS;
                            case PHYSFS_ERR_PERMISSION:
                                return WASI_EPERM;
                            default:
                                return WASI_EIO;
                        }
                    }

                    WASM_SET(u32, result, wasi->allocate_file_descriptor(wasi_fd_type::FSFILE, handle));
                }

                return WASI_ESUCCESS;
            }
    }

    return WASI_EBADF;
}

extern "C" u32 w2c_wasi__snapshot__preview1_path_readlink(wasi_t *wasi, u32 fd, usize path, u32 path_len, usize buf, u32 buf_len, usize result) {
    WASI_DEBUG("path_readlink(%u, \"%.*s\", 0x%08x (%u))\n", fd, path_len, (char *)WASM_MEM(path), buf, buf_len);
    return WASI_ENOSYS;
}

extern "C" u32 w2c_wasi__snapshot__preview1_path_remove_directory(wasi_t *wasi, u32 fd, usize path, u32 path_len) {
    WASI_DEBUG("path_remove_directory(%u, \"%.*s\")\n", fd, path_len, (char *)WASM_MEM(path));

    if (fd >= wasi->fdtable.size()) {
        return WASI_EBADF;
    }

    switch (wasi->fdtable[fd].type) {
        case wasi_fd_type::VACANT:
            return WASI_EBADF;

        case wasi_fd_type::STDIN:
        case wasi_fd_type::STDOUT:
        case wasi_fd_type::STDERR:
        case wasi_fd_type::FSFILE:
            return WASI_EINVAL;

        case wasi_fd_type::FS:
        case wasi_fd_type::FSDIR:
            {
                if (!wasi->fdtable[fd].dir_handle()->writable) {
                    return WASI_EROFS;
                }

                PHYSFS_Stat stat;
                std::string new_path(wasi->fdtable[fd].dir_handle()->path);
                new_path.push_back('/');
                new_path.append((const char *)WASM_MEM(path), strlen_safe((const char *)WASM_MEM(path), path_len));
                new_path = mkxp_retro::fs->normalize(new_path.c_str(), false, true);

                // Verify that the path we're opening is a descendant of the directory corresponding to `fd`
                if (std::strncmp(new_path.c_str(), wasi->fdtable[fd].dir_handle()->path.c_str(), wasi->fdtable[fd].dir_handle()->path.length()) != 0) {
                    return WASI_EPERM;
                }

                if (!PHYSFS_stat(wasi->fdtable[fd].dir_handle()->path.c_str(), &stat)) {
                    return WASI_ENOENT;
                }

                if (stat.filetype != PHYSFS_FILETYPE_DIRECTORY) {
                    return WASI_ENOTDIR;
                }

                struct fs_dir *root = wasi->fdtable[fd].dir_handle()->root != nullptr ? wasi->fdtable[fd].dir_handle()->root : wasi->fdtable[fd].dir_handle();
                if (!PHYSFS_delete(new_path.c_str() + root->path.length())) {
                    switch (PHYSFS_getLastErrorCode()) {
                        case PHYSFS_ERR_DIR_NOT_EMPTY:
                            return WASI_ENOTEMPTY;
                        case PHYSFS_ERR_READ_ONLY:
                        case PHYSFS_ERR_NO_WRITE_DIR:
                            return WASI_EROFS;
                        case PHYSFS_ERR_PERMISSION:
                            return WASI_EPERM;
                        default:
                            return WASI_EIO;
                    }
                }

                return WASI_ESUCCESS;
            }
    }

    return WASI_EBADF;
}

extern "C" u32 w2c_wasi__snapshot__preview1_path_rename(wasi_t *wasi, u32 fd, usize old_path, u32 old_path_len, u32 new_fd, usize new_path, u32 new_path_len) {
    WASI_DEBUG("path_rename(%u, \"%.*s\", %u, \"%.*s\")\n", fd, old_path_len, (char *)WASM_MEM(old_path), new_fd, new_path_len, (char *)WASM_MEM(new_path));
    return WASI_ENOSYS;
}

extern "C" u32 w2c_wasi__snapshot__preview1_path_symlink(wasi_t *wasi, usize old_path, u32 old_path_len, u32 fd, usize new_path, u32 new_path_len) {
    WASI_DEBUG("path_symlink(\"%.*s\", %u, \"%.*s\")\n", old_path_len, (char *)WASM_MEM(old_path), fd, new_path_len, (char *)WASM_MEM(new_path));
    return WASI_ENOSYS;
}

extern "C" u32 w2c_wasi__snapshot__preview1_path_unlink_file(wasi_t *wasi, u32 fd, usize path, u32 path_len) {
    WASI_DEBUG("path_unlink_file(%u, \"%.*s\")\n", fd, path_len, (char *)WASM_MEM(path));

    if (fd >= wasi->fdtable.size()) {
        return WASI_EBADF;
    }

    switch (wasi->fdtable[fd].type) {
        case wasi_fd_type::VACANT:
            return WASI_EBADF;

        case wasi_fd_type::STDIN:
        case wasi_fd_type::STDOUT:
        case wasi_fd_type::STDERR:
        case wasi_fd_type::FSFILE:
            return WASI_EINVAL;

        case wasi_fd_type::FS:
        case wasi_fd_type::FSDIR:
            {
                if (!wasi->fdtable[fd].dir_handle()->writable) {
                    return WASI_EROFS;
                }

                PHYSFS_Stat stat;
                std::string new_path(wasi->fdtable[fd].dir_handle()->path);
                new_path.push_back('/');
                new_path.append((const char *)WASM_MEM(path), strlen_safe((const char *)WASM_MEM(path), path_len));
                new_path = mkxp_retro::fs->normalize(new_path.c_str(), false, true);

                // Verify that the path we're opening is a descendant of the directory corresponding to `fd`
                if (std::strncmp(new_path.c_str(), wasi->fdtable[fd].dir_handle()->path.c_str(), wasi->fdtable[fd].dir_handle()->path.length()) != 0) {
                    return WASI_EPERM;
                }

                if (!PHYSFS_stat(wasi->fdtable[fd].dir_handle()->path.c_str(), &stat)) {
                    return WASI_ENOENT;
                }

                if (stat.filetype == PHYSFS_FILETYPE_DIRECTORY) {
                    return WASI_EISDIR;
                } else if (stat.filetype != PHYSFS_FILETYPE_REGULAR) {
                    return WASI_EIO;
                }

                struct fs_dir *root = wasi->fdtable[fd].dir_handle()->root != nullptr ? wasi->fdtable[fd].dir_handle()->root : wasi->fdtable[fd].dir_handle();
                if (!PHYSFS_delete(new_path.c_str() + root->path.length())) {
                    switch (PHYSFS_getLastErrorCode()) {
                        case PHYSFS_ERR_READ_ONLY:
                        case PHYSFS_ERR_NO_WRITE_DIR:
                            return WASI_EROFS;
                        case PHYSFS_ERR_PERMISSION:
                            return WASI_EPERM;
                        default:
                            return WASI_EIO;
                    }
                }

                return WASI_ESUCCESS;
            }
    }

    return WASI_EBADF;
}

extern "C" u32 w2c_wasi__snapshot__preview1_poll_oneoff(wasi_t *wasi, usize in, usize out, u32 nsubscriptions, usize result) {
    WASI_DEBUG("poll_oneoff(0x%08x, 0x%08x, %u)\n", in, out, nsubscriptions);
    return WASI_ENOSYS;
}

extern "C" void w2c_wasi__snapshot__preview1_proc_exit(wasi_t *wasi, u32 rval) {
    WASI_DEBUG("proc_exit(%u)\n", rval);
    std::abort();
}

extern "C" u32 w2c_wasi__snapshot__preview1_random_get(wasi_t *wasi, usize buf, u32 buf_len) {
    WASI_DEBUG("random_get(0x%08x (%u))\n", buf, buf_len);

    static std::random_device dev;
    static std::mt19937 rng(dev());

    static u32 rng_buffer;
    static u32 rng_buffer_size = 0;

    while (buf_len > 0) {
        if (rng_buffer_size == 0) {
            rng_buffer = rng();
            rng_buffer_size = 4;
        } else {
            u32 n = std::min(rng_buffer_size, buf_len);
            std::memcpy(WASM_MEM(buf), (u8 *)&rng_buffer + (4 - n), n);
            buf += n;
            buf_len -= n;
            rng_buffer_size -= n;
        }
    }
    return WASI_ESUCCESS;
}