/*
 * This file is part of the MicroPython project, http://micropython.org/
 *
 * The MIT License (MIT)
 *
 * Copyright (c) 2013-2016 Damien P. George
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 * THE SOFTWARE.
 */

#include <stdint.h>
#include <stdio.h>
#include <string.h>
#include <assert.h>

#include "py/reader.h"
#include "py/emitglue.h"
#include "py/persistentcode.h"
#include "py/bc.h"

#if MICROPY_PERSISTENT_CODE_LOAD || MICROPY_PERSISTENT_CODE_SAVE

#include "py/smallint.h"

// The current version of .mpy files
#define MPY_VERSION (3)

// The feature flags byte encodes the compile-time config options that
// affect the generate bytecode.
#define MPY_FEATURE_FLAGS ( \
    ((MICROPY_OPT_CACHE_MAP_LOOKUP_IN_BYTECODE) << 0) \
    | ((MICROPY_PY_BUILTINS_STR_UNICODE) << 1) \
    )
// This is a version of the flags that can be configured at runtime.
#define MPY_FEATURE_FLAGS_DYNAMIC ( \
    ((MICROPY_OPT_CACHE_MAP_LOOKUP_IN_BYTECODE_DYNAMIC) << 0) \
    | ((MICROPY_PY_BUILTINS_STR_UNICODE_DYNAMIC) << 1) \
    )

#if MICROPY_PERSISTENT_CODE_LOAD || (MICROPY_PERSISTENT_CODE_SAVE && !MICROPY_DYNAMIC_COMPILER)
// The bytecode will depend on the number of bits in a small-int, and
// this function computes that (could make it a fixed constant, but it
// would need to be defined in mpconfigport.h).
STATIC int mp_small_int_bits(void) {
    mp_int_t i = MP_SMALL_INT_MAX;
    int n = 1;
    while (i != 0) {
        i >>= 1;
        ++n;
    }
    return n;
}
#endif

typedef struct _bytecode_prelude_t {
    uint n_state;
    uint n_exc_stack;
    uint scope_flags;
    uint n_pos_args;
    uint n_kwonly_args;
    uint n_def_pos_args;
    uint code_info_size;
} bytecode_prelude_t;

// ip will point to start of opcodes
// ip2 will point to simple_name, source_file qstrs
STATIC void extract_prelude(const byte **ip, const byte **ip2, bytecode_prelude_t *prelude) {
    prelude->n_state = mp_decode_uint(ip);
    prelude->n_exc_stack = mp_decode_uint(ip);
    prelude->scope_flags = *(*ip)++;
    prelude->n_pos_args = *(*ip)++;
    prelude->n_kwonly_args = *(*ip)++;
    prelude->n_def_pos_args = *(*ip)++;
    *ip2 = *ip;
    prelude->code_info_size = mp_decode_uint(ip2);
    *ip += prelude->code_info_size;
    while (*(*ip)++ != 255) {
    }
}

#endif // MICROPY_PERSISTENT_CODE_LOAD || MICROPY_PERSISTENT_CODE_SAVE

#if MICROPY_PERSISTENT_CODE_LOAD

#include "py/parsenum.h"

STATIC int read_byte(mp_reader_t *reader) {
    return reader->readbyte(reader->data);
}

STATIC void read_bytes(mp_reader_t *reader, byte *buf, size_t len) {
    while (len-- > 0) {
        *buf++ = reader->readbyte(reader->data);
    }
}

STATIC size_t read_uint(mp_reader_t *reader) {
    size_t unum = 0;
    for (;;) {
        byte b = reader->readbyte(reader->data);
        unum = (unum << 7) | (b & 0x7f);
        if ((b & 0x80) == 0) {
            break;
        }
    }
    return unum;
}

STATIC qstr load_qstr(mp_reader_t *reader) {
    size_t len = read_uint(reader);
    char *str = m_new(char, len);
    read_bytes(reader, (byte*)str, len);
    qstr qst = qstr_from_strn(str, len);
    m_del(char, str, len);
    return qst;
}

STATIC mp_obj_t load_obj(mp_reader_t *reader) {
    byte obj_type = read_byte(reader);
    if (obj_type == 'e') {
        return MP_OBJ_FROM_PTR(&mp_const_ellipsis_obj);
    } else {
        size_t len = read_uint(reader);
        vstr_t vstr;
        vstr_init_len(&vstr, len);
        read_bytes(reader, (byte*)vstr.buf, len);
        if (obj_type == 's' || obj_type == 'b') {
            return mp_obj_new_str_from_vstr(obj_type == 's' ? &mp_type_str : &mp_type_bytes, &vstr);
        } else if (obj_type == 'i') {
            return mp_parse_num_integer(vstr.buf, vstr.len, 10, NULL);
        } else {
            assert(obj_type == 'f' || obj_type == 'c');
            return mp_parse_num_decimal(vstr.buf, vstr.len, obj_type == 'c', false, NULL);
        }
    }
}

STATIC void load_bytecode_qstrs(mp_reader_t *reader, byte *ip, byte *ip_top) {
    while (ip < ip_top) {
        size_t sz;
        uint f = mp_opcode_format(ip, &sz);
        if (f == MP_OPCODE_QSTR) {
            qstr qst = load_qstr(reader);
            ip[1] = qst;
            ip[2] = qst >> 8;
        }
        ip += sz;
    }
}

STATIC mp_raw_code_t *load_raw_code(mp_reader_t *reader) {
    // load bytecode
    size_t bc_len = read_uint(reader);
    byte *bytecode = m_new(byte, bc_len);
    read_bytes(reader, bytecode, bc_len);

    // extract prelude
    const byte *ip = bytecode;
    const byte *ip2;
    bytecode_prelude_t prelude;
    extract_prelude(&ip, &ip2, &prelude);

    // load qstrs and link global qstr ids into bytecode
    qstr simple_name = load_qstr(reader);
    qstr source_file = load_qstr(reader);
    ((byte*)ip2)[0] = simple_name; ((byte*)ip2)[1] = simple_name >> 8;
    ((byte*)ip2)[2] = source_file; ((byte*)ip2)[3] = source_file >> 8;
    load_bytecode_qstrs(reader, (byte*)ip, bytecode + bc_len);

    // load constant table
    size_t n_obj = read_uint(reader);
    size_t n_raw_code = read_uint(reader);
    mp_uint_t *const_table = m_new(mp_uint_t, prelude.n_pos_args + prelude.n_kwonly_args + n_obj + n_raw_code);
    mp_uint_t *ct = const_table;
    for (size_t i = 0; i < prelude.n_pos_args + prelude.n_kwonly_args; ++i) {
        *ct++ = (mp_uint_t)MP_OBJ_NEW_QSTR(load_qstr(reader));
    }
    for (size_t i = 0; i < n_obj; ++i) {
        *ct++ = (mp_uint_t)load_obj(reader);
    }
    for (size_t i = 0; i < n_raw_code; ++i) {
        *ct++ = (mp_uint_t)(uintptr_t)load_raw_code(reader);
    }

    // create raw_code and return it
    mp_raw_code_t *rc = mp_emit_glue_new_raw_code();
    mp_emit_glue_assign_bytecode(rc, bytecode,
        #if MICROPY_PERSISTENT_CODE_SAVE || MICROPY_DEBUG_PRINTERS
        bc_len,
        #endif
        const_table,
        #if MICROPY_PERSISTENT_CODE_SAVE
        n_obj, n_raw_code,
        #endif
        prelude.scope_flags);
    return rc;
}

mp_raw_code_t *mp_raw_code_load(mp_reader_t *reader) {
    byte header[4];
    read_bytes(reader, header, sizeof(header));
    if (header[0] != 'M'
        || header[1] != MPY_VERSION
        || header[2] != MPY_FEATURE_FLAGS
        || header[3] > mp_small_int_bits()) {
        mp_raise_ValueError("incompatible .mpy file");
    }
    mp_raw_code_t *rc = load_raw_code(reader);
    reader->close(reader->data);
    return rc;
}

mp_raw_code_t *mp_raw_code_load_mem(const byte *buf, size_t len) {
    mp_reader_t reader;
    mp_reader_new_mem(&reader, buf, len, 0);
    return mp_raw_code_load(&reader);
}

mp_raw_code_t *mp_raw_code_load_file(const char *filename) {
    mp_reader_t reader;
    mp_reader_new_file(&reader, filename);
    return mp_raw_code_load(&reader);
}

#endif // MICROPY_PERSISTENT_CODE_LOAD

#if MICROPY_PERSISTENT_CODE_SAVE

#include "py/objstr.h"

STATIC void mp_print_bytes(mp_print_t *print, const byte *data, size_t len) {
    print->print_strn(print->data, (const char*)data, len);
}

#define BYTES_FOR_INT ((BYTES_PER_WORD * 8 + 6) / 7)
STATIC void mp_print_uint(mp_print_t *print, size_t n) {
    byte buf[BYTES_FOR_INT];
    byte *p = buf + sizeof(buf);
    *--p = n & 0x7f;
    n >>= 7;
    for (; n != 0; n >>= 7) {
        *--p = 0x80 | (n & 0x7f);
    }
    print->print_strn(print->data, (char*)p, buf + sizeof(buf) - p);
}

STATIC void save_qstr(mp_print_t *print, qstr qst) {
    size_t len;
    const byte *str = qstr_data(qst, &len);
    mp_print_uint(print, len);
    mp_print_bytes(print, str, len);
}

STATIC void save_obj(mp_print_t *print, mp_obj_t o) {
    if (MP_OBJ_IS_STR_OR_BYTES(o)) {
        byte obj_type;
        if (MP_OBJ_IS_STR(o)) {
            obj_type = 's';
        } else {
            obj_type = 'b';
        }
        mp_uint_t len;
        const char *str = mp_obj_str_get_data(o, &len);
        mp_print_bytes(print, &obj_type, 1);
        mp_print_uint(print, len);
        mp_print_bytes(print, (const byte*)str, len);
    } else if (MP_OBJ_TO_PTR(o) == &mp_const_ellipsis_obj) {
        byte obj_type = 'e';
        mp_print_bytes(print, &obj_type, 1);
    } else {
        // we save numbers using a simplistic text representation
        // TODO could be improved
        byte obj_type;
        if (MP_OBJ_IS_TYPE(o, &mp_type_int)) {
            obj_type = 'i';
        #if MICROPY_PY_BUILTINS_COMPLEX
        } else if (MP_OBJ_IS_TYPE(o, &mp_type_complex)) {
            obj_type = 'c';
        #endif
        } else {
            assert(mp_obj_is_float(o));
            obj_type = 'f';
        }
        vstr_t vstr;
        mp_print_t pr;
        vstr_init_print(&vstr, 10, &pr);
        mp_obj_print_helper(&pr, o, PRINT_REPR);
        mp_print_bytes(print, &obj_type, 1);
        mp_print_uint(print, vstr.len);
        mp_print_bytes(print, (const byte*)vstr.buf, vstr.len);
        vstr_clear(&vstr);
    }
}

STATIC void save_bytecode_qstrs(mp_print_t *print, const byte *ip, const byte *ip_top) {
    while (ip < ip_top) {
        size_t sz;
        uint f = mp_opcode_format(ip, &sz);
        if (f == MP_OPCODE_QSTR) {
            qstr qst = ip[1] | (ip[2] << 8);
            save_qstr(print, qst);
        }
        ip += sz;
    }
}

STATIC void save_raw_code(mp_print_t *print, mp_raw_code_t *rc) {
    if (rc->kind != MP_CODE_BYTECODE) {
        mp_raise_ValueError("can only save bytecode");
    }

    // save bytecode
    mp_print_uint(print, rc->data.u_byte.bc_len);
    mp_print_bytes(print, rc->data.u_byte.bytecode, rc->data.u_byte.bc_len);

    // extract prelude
    const byte *ip = rc->data.u_byte.bytecode;
    const byte *ip2;
    bytecode_prelude_t prelude;
    extract_prelude(&ip, &ip2, &prelude);

    // save qstrs
    save_qstr(print, ip2[0] | (ip2[1] << 8)); // simple_name
    save_qstr(print, ip2[2] | (ip2[3] << 8)); // source_file
    save_bytecode_qstrs(print, ip, rc->data.u_byte.bytecode + rc->data.u_byte.bc_len);

    // save constant table
    mp_print_uint(print, rc->data.u_byte.n_obj);
    mp_print_uint(print, rc->data.u_byte.n_raw_code);
    const mp_uint_t *const_table = rc->data.u_byte.const_table;
    for (uint i = 0; i < prelude.n_pos_args + prelude.n_kwonly_args; ++i) {
        mp_obj_t o = (mp_obj_t)*const_table++;
        save_qstr(print, MP_OBJ_QSTR_VALUE(o));
    }
    for (uint i = 0; i < rc->data.u_byte.n_obj; ++i) {
        save_obj(print, (mp_obj_t)*const_table++);
    }
    for (uint i = 0; i < rc->data.u_byte.n_raw_code; ++i) {
        save_raw_code(print, (mp_raw_code_t*)(uintptr_t)*const_table++);
    }
}

void mp_raw_code_save(mp_raw_code_t *rc, mp_print_t *print) {
    // header contains:
    //  byte  'M'
    //  byte  version
    //  byte  feature flags
    //  byte  number of bits in a small int
    byte header[4] = {'M', MPY_VERSION, MPY_FEATURE_FLAGS_DYNAMIC,
        #if MICROPY_DYNAMIC_COMPILER
        mp_dynamic_compiler.small_int_bits,
        #else
        mp_small_int_bits(),
        #endif
    };
    mp_print_bytes(print, header, sizeof(header));

    save_raw_code(print, rc);
}

// here we define mp_raw_code_save_file depending on the port
// TODO abstract this away properly

#if defined(__i386__) || defined(__x86_64__) || defined(__unix__)

#include <unistd.h>
#include <sys/stat.h>
#include <fcntl.h>

STATIC void fd_print_strn(void *env, const char *str, size_t len) {
    int fd = (intptr_t)env;
    ssize_t ret = write(fd, str, len);
    (void)ret;
}

void mp_raw_code_save_file(mp_raw_code_t *rc, const char *filename) {
    int fd = open(filename, O_WRONLY | O_CREAT | O_TRUNC, 0644);
    mp_print_t fd_print = {(void*)(intptr_t)fd, fd_print_strn};
    mp_raw_code_save(rc, &fd_print);
    close(fd);
}

#else
#error mp_raw_code_save_file not implemented for this platform
#endif

#endif // MICROPY_PERSISTENT_CODE_SAVE