// Copyright 2017 The Fuchsia Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include <errno.h>
#include <fcntl.h>
#include <limits.h>
#include <new>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <sys/stat.h>
#include <unistd.h>

#include <fbl/algorithm.h>
#include <fbl/unique_ptr.h>
#include <fuchsia/io/c/fidl.h>
#include <fvm/format.h>
#include <lib/fzl/fdio.h>
#include <minfs/format.h>
#include <unittest/unittest.h>
#include <zircon/compiler.h>
#include <zircon/syscalls.h>

#include "filesystems.h"
#include "misc.h"

namespace {

bool QueryInfo(uint64_t* out_free_pool_size) {
    BEGIN_HELPER;
    fuchsia_io_FilesystemInfo info;
    fbl::unique_fd fd(open(kMountPath, O_RDONLY | O_DIRECTORY));
    ASSERT_TRUE(fd);
    zx_status_t status;
    fzl::FdioCaller caller(std::move(fd));
    ASSERT_EQ(fuchsia_io_DirectoryAdminQueryFilesystem(caller.borrow_channel(), &status, &info),
              ZX_OK);
    // This should always be true, for all filesystems.
    ASSERT_GT(info.total_bytes, info.used_bytes);
    *out_free_pool_size = info.free_shared_pool_bytes;
    END_HELPER;
}

bool EnsureCanGrow() {
    BEGIN_HELPER;
    uint64_t free_pool_size;
    ASSERT_TRUE(QueryInfo(&free_pool_size));
    // This tests expects to run with free FVM space.
    ASSERT_GT(free_pool_size, 0);
    END_HELPER;
}

bool EnsureCannotGrow() {
    BEGIN_HELPER;
    uint64_t free_pool_size;
    ASSERT_TRUE(QueryInfo(&free_pool_size));
    ASSERT_EQ(free_pool_size, 0);
    END_HELPER;
}

const test_disk_t max_inode_disk = {
    .block_count = 1LLU << 15,
    .block_size = 1LLU << 9,
    .slice_size = 1LLU << 20,
};

template <bool Remount>
bool TestUseAllInodes() {
    BEGIN_TEST;
    if (use_real_disk) {
        fprintf(stderr, "Ramdisk required; skipping test\n");
        return true;
    }
    ASSERT_TRUE(test_info->supports_resize);
    ASSERT_TRUE(EnsureCanGrow());

    // Create 100,000 inodes.
    // We expect that this will force enough inodes to cause the
    // filesystem structures to resize partway through.
    constexpr size_t kFilesPerDirectory = 100;
    size_t d = 0;
    while (true) {
        if (d % 100 == 0) {
            printf("Creating directory (containing 100 files): %lu\n", d);
        }
        char dname[128];
        snprintf(dname, sizeof(dname), "::%lu", d);
        if (mkdir(dname, 0666) < 0) {
            ASSERT_EQ(errno, ENOSPC);
            break;
        }
        bool stop = false;
        for (size_t f = 0; f < kFilesPerDirectory; f++) {
            char fname[128];
            snprintf(fname, sizeof(fname), "::%lu/%lu", d, f);
            fbl::unique_fd fd(open(fname, O_CREAT | O_RDWR | O_EXCL));
            if (!fd) {
                ASSERT_EQ(errno, ENOSPC);
                stop = true;
                break;
            }
        }
        if (stop) {
            break;
        }
        d++;
    }

    ASSERT_TRUE(EnsureCannotGrow());

    if (Remount) {
        printf("Unmounting, Re-mounting, verifying...\n");
        ASSERT_TRUE(check_remount(), "Could not remount filesystem");
    }

    size_t directory_count = d;
    for (size_t d = 0; d < directory_count; d++) {
        if (d % 100 == 0) {
            printf("Deleting directory (containing 100 files): %lu\n", d);
        }
        for (size_t f = 0; f < kFilesPerDirectory; f++) {
            char fname[128];
            snprintf(fname, sizeof(fname), "::%lu/%lu", d, f);
            ASSERT_EQ(unlink(fname), 0);
        }
        char dname[128];
        snprintf(dname, sizeof(dname), "::%lu", d);
        ASSERT_EQ(rmdir(dname), 0);
    }

    END_TEST;
}

const test_disk_t max_data_disk = {
    .block_count = 1LLU << 17,
    .block_size = 1LLU << 9,
    .slice_size = 1LLU << 20,
};

template <bool Remount>
bool TestUseAllData() {
    BEGIN_TEST;
    if (use_real_disk) {
        fprintf(stderr, "Ramdisk required; skipping test\n");
        return true;
    }
    constexpr size_t kBufSize = (1 << 20);
    constexpr size_t kFileBufCount = 20;
    ASSERT_TRUE(test_info->supports_resize);
    ASSERT_TRUE(EnsureCanGrow());

    uint64_t disk_size = test_disk_info.block_count * test_disk_info.block_size;
    size_t metadata_size = fvm::MetadataSize(disk_size, max_data_disk.slice_size);

    ASSERT_GT(disk_size, metadata_size * 2);
    disk_size -= 2 * metadata_size;

    ASSERT_GT(disk_size, minfs::kMinfsMinimumSlices * max_data_disk.slice_size);
    disk_size -= minfs::kMinfsMinimumSlices * max_data_disk.slice_size;

    fbl::unique_ptr<uint8_t[]> buf(new uint8_t[kBufSize]);
    memset(buf.get(), 0, kBufSize);

    size_t f = 0;
    while (true) {
        printf("Creating 20 MB file #%lu\n", f);
        char fname[128];
        snprintf(fname, sizeof(fname), "::%lu", f);
        fbl::unique_fd fd(open(fname, O_CREAT | O_RDWR | O_EXCL));
        if (!fd) {
            ASSERT_EQ(errno, ENOSPC);
            break;
        }
        f++;
        bool stop = false;
        for (size_t i = 0; i < kFileBufCount; i++) {
            ASSERT_EQ(ftruncate(fd.get(), kBufSize * kFileBufCount), 0);
            ssize_t r = write(fd.get(), buf.get(), kBufSize);
            if (r != kBufSize) {
                ASSERT_EQ(errno, ENOSPC);
                stop = true;
                break;
            }
        }
        if (stop) {
            break;
        }
    }

    ASSERT_TRUE(EnsureCannotGrow());

    if (Remount) {
        printf("Unmounting, Re-mounting, verifying...\n");
        ASSERT_TRUE(check_remount(), "Could not remount filesystem");
    }

    size_t file_count = f;
    for (size_t f = 0; f < file_count; f++) {
        char fname[128];
        snprintf(fname, sizeof(fname), "::%lu", f);
        ASSERT_EQ(unlink(fname), 0);
    }

    END_TEST;
}

}  // namespace

// Reformat the disk between tests to restore original size.
RUN_FOR_ALL_FILESYSTEMS_TYPE(fs_resize_tests_inodes_remount, max_inode_disk, FS_TEST_FVM,
    RUN_TEST_LARGE((TestUseAllInodes<true>))
)

RUN_FOR_ALL_FILESYSTEMS_TYPE(fs_resize_tests_inodes, max_inode_disk, FS_TEST_FVM,
    RUN_TEST_LARGE((TestUseAllInodes<false>))
)

RUN_FOR_ALL_FILESYSTEMS_TYPE(fs_resize_tests_data_remount, max_data_disk, FS_TEST_FVM,
    RUN_TEST_LARGE((TestUseAllData<true>))
)

RUN_FOR_ALL_FILESYSTEMS_TYPE(fs_resize_tests_data, max_data_disk, FS_TEST_FVM,
    RUN_TEST_LARGE((TestUseAllData<false>))
)