// pw.fs: read-only access to the pack's files. The host confines every path to the pack root
// and enforces every limit (SPEC.md section 7.5).

#include "bindings.hpp"
#include "host.hpp"
#include "lua.h"
#include "lualib.h"

#include <cstdint>
#include <string_view>

namespace packluau::bindings {

namespace {

/// 16 MiB by default; never more than 1 GiB in one read.
constexpr std::uint64_t default_limit = 16ULL << 20U;
constexpr std::uint64_t maximum_limit = 1ULL << 30U;

int read(lua_State *state) {
    const std::string_view path = check_string(state, 1);
    const std::uint64_t limit = limit_option(state, 2, default_limit, maximum_limit);
    RunContext &run = context(state, Capability::read_fs);
    pl_str bytes{};
    check(state, run, run.host->fs_read(run.host->ctx, str(path), limit, &bytes), "pw.fs.read");
    const std::string_view text = view(bytes);
    push_text(state, text);
    return 1;
}

int list(lua_State *state) {
    const std::string_view directory = check_string(state, 1);
    RunContext &run = context(state, Capability::read_fs);
    pl_str_list entries{};
    check(state, run, run.host->fs_list(run.host->ctx, str(directory), &entries), "pw.fs.list");
    push_list(state, entries);
    return 1;
}

pl_file_kind kind_of(lua_State *state) {
    const std::string_view path = check_string(state, 1);
    RunContext &run = context(state, Capability::read_fs);
    pl_file_kind kind = PL_FILE_NONE;
    check(state, run, run.host->fs_stat(run.host->ctx, str(path), &kind), "pw.fs");
    return kind;
}

int exists(lua_State *state) {
    lua_pushboolean(state, kind_of(state) != PL_FILE_NONE ? 1 : 0);
    return 1;
}

int is_directory(lua_State *state) {
    lua_pushboolean(state, kind_of(state) == PL_FILE_DIRECTORY ? 1 : 0);
    return 1;
}

int is_symlink(lua_State *state) {
    lua_pushboolean(state, kind_of(state) == PL_FILE_SYMLINK ? 1 : 0);
    return 1;
}

int sha512(lua_State *state) {
    const std::string_view path = check_string(state, 1);
    RunContext &run = context(state, Capability::read_fs);
    pl_str hex{};
    check(state, run, run.host->fs_sha512(run.host->ctx, str(path), &hex), "pw.fs.sha512");
    const std::string_view text = view(hex);
    push_text(state, text);
    return 1;
}

} // namespace

void install_fs(lua_State *state) {
    lua_createtable(state, 0, 6);
    lua_pushcfunction(state, &read, "pw.fs.read");
    lua_setfield(state, -2, "read");
    lua_pushcfunction(state, &list, "pw.fs.list");
    lua_setfield(state, -2, "list");
    lua_pushcfunction(state, &exists, "pw.fs.exists");
    lua_setfield(state, -2, "exists");
    lua_pushcfunction(state, &is_directory, "pw.fs.is_directory");
    lua_setfield(state, -2, "is_directory");
    lua_pushcfunction(state, &is_symlink, "pw.fs.is_symlink");
    lua_setfield(state, -2, "is_symlink");
    lua_pushcfunction(state, &sha512, "pw.fs.sha512");
    lua_setfield(state, -2, "sha512");
    seal(state);
}

} // namespace packluau::bindings