/* Standard I/O implementation for OctaSTD.
 *
 * This file is part of OctaSTD. See COPYING.md for futher information.
 */

#ifndef OSTD_IO_HH
#define OSTD_IO_HH

#include <stdio.h>

#include <vector>

#include "ostd/platform.hh"
#include "ostd/string.hh"
#include "ostd/stream.hh"
#include "ostd/format.hh"

namespace ostd {

enum class StreamMode {
    read = 0, write, append, read_u, write_u, append_u
};

namespace detail {
    static char const *filemodes[] = {
        "rb", "wb", "ab", "rb+", "wb+", "ab+"
    };
}

struct FileStream: Stream {
    FileStream(): p_f(), p_owned(false) {}
    FileStream(FileStream const &) = delete;
    FileStream(FileStream &&s): p_f(s.p_f), p_owned(s.p_owned) {
        s.p_f = nullptr;
        s.p_owned = false;
    }

    FileStream(ConstCharRange path, StreamMode mode = StreamMode::read): p_f() {
        open(path, mode);
    }

    FileStream(FILE *f): p_f(f), p_owned(false) {}

    ~FileStream() { close(); }

    FileStream &operator=(FileStream const &) = delete;
    FileStream &operator=(FileStream &&s) {
        close();
        swap(s);
        return *this;
    }

    bool open(ConstCharRange path, StreamMode mode = StreamMode::read) {
        if (p_f || (path.size() > FILENAME_MAX)) {
            return false;
        }
        char buf[FILENAME_MAX + 1];
        memcpy(buf, &path[0], path.size());
        buf[path.size()] = '\0';
        p_owned = false;
#ifndef OSTD_PLATFORM_WIN32
        p_f = fopen(buf, detail::filemodes[Size(mode)]);
#else
        if (fopen_s(&p_f, buf, detail::filemodes[Size(mode)]) != 0) {
            return false;
        }
#endif
        p_owned = !!p_f;
        return is_open();
    }

    bool open(FILE *f) {
        if (p_f) {
            return false;
        }
        p_f = f;
        p_owned = false;
        return is_open();
    }

    bool is_open() const { return p_f != nullptr; }
    bool is_owned() const { return p_owned; }

    void close() {
        if (p_f && p_owned) {
            fclose(p_f);
        }
        p_f = nullptr;
        p_owned = false;
    }

    bool end() const {
        return feof(p_f) != 0;
    }

    bool seek(StreamOffset pos, StreamSeek whence = StreamSeek::set) {
#ifndef OSTD_PLATFORM_WIN32
        return fseeko(p_f, pos, int(whence)) >= 0;
#else
        return _fseeki64(p_f, pos, int(whence)) >= 0;
#endif
    }

    StreamOffset tell() const {
#ifndef OSTD_PLATFORM_WIN32
        return ftello(p_f);
#else
        return _ftelli64(p_f);
#endif
    }

    bool flush() { return !fflush(p_f); }

    Size read_bytes(void *buf, Size count) {
        return fread(buf, 1, count, p_f);
    }

    Size write_bytes(void const *buf, Size count) {
        return fwrite(buf, 1, count, p_f);
    }

    int getchar() {
        return fgetc(p_f);
    }

    bool putchar(int c) {
        return  fputc(c, p_f) != EOF;
    }

    void swap(FileStream &s) {
        ostd::swap(p_f, s.p_f);
        ostd::swap(p_owned, s.p_owned);
    }

    FILE *get_file() { return p_f; }

private:
    FILE *p_f;
    bool p_owned;
};

static FileStream in(stdin);
static FileStream out(stdout);
static FileStream err(stderr);

/* no need to call anything from FileStream, prefer simple calls... */

namespace detail {
    struct IoNat {};

    inline void write_impl(ConstCharRange s) {
        fwrite(&s[0], 1, s.size(), stdout);
    }

    template<typename T>
    inline void write_impl(
        T const &v, EnableIf<
            !IsConstructible<ConstCharRange, T const &>, IoNat
        > = IoNat()
    ) {
        write(ostd::to_string(v));
    }
}

template<typename T>
inline void write(T const &v) {
    detail::write_impl(v);
}

template<typename T, typename ...A>
inline void write(T const &v, A const &...args) {
    write(v);
    write(args...);
}

template<typename T>
inline void writeln(T const &v) {
    write(v);
    putc('\n', stdout);
}

template<typename T, typename ...A>
inline void writeln(T const &v, A const &...args) {
    write(v);
    write(args...);
    putc('\n', stdout);
}

template<typename ...A>
inline void writef(ConstCharRange fmt, A const &...args) {
    char buf[512];
    Ptrdiff need = format(
        detail::FormatOutRange<sizeof(buf)>(buf), fmt, args...
    );
    if (need < 0) {
        return;
    } else if (Size(need) < sizeof(buf)) {
        fwrite(buf, 1, need, stdout);
        return;
    }
    std::vector<char> s;
    s.reserve(need);
    format(detail::UnsafeWritefRange(s.data()), fmt, args...);
    fwrite(s.data(), 1, need, stdout);
}

template<typename ...A>
inline void writefln(ConstCharRange fmt, A const &...args) {
    writef(fmt, args...);
    putc('\n', stdout);
}

} /* namespace ostd */

#endif