/*
 * This file is part of the Micro Python project, http://micropython.org/
 *
 * The MIT License (MIT)
 *
 * Copyright (c) 2013, 2014 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.
 */

// This code glues the code emitters to the runtime.

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

#include "py/emitglue.h"
#include "py/runtime0.h"
#include "py/bc.h"

#if 0 // print debugging info
#define DEBUG_PRINT (1)
#define WRITE_CODE (1)
#define DEBUG_printf DEBUG_printf
#define DEBUG_OP_printf(...) DEBUG_printf(__VA_ARGS__)
#else // don't print debugging info
#define DEBUG_printf(...) (void)0
#define DEBUG_OP_printf(...) (void)0
#endif

#if MICROPY_DEBUG_PRINTERS
mp_uint_t mp_verbose_flag = 0;
#endif

struct _mp_raw_code_t {
    mp_raw_code_kind_t kind : 3;
    mp_uint_t scope_flags : 7;
    mp_uint_t n_pos_args : 11;
    union {
        struct {
            const byte *bytecode;
            const mp_uint_t *const_table;
            #if MICROPY_PERSISTENT_CODE_SAVE
            mp_uint_t bc_len;
            uint16_t n_obj;
            uint16_t n_raw_code;
            #endif
        } u_byte;
        struct {
            void *fun_data;
            const mp_uint_t *const_table;
            mp_uint_t type_sig; // for viper, compressed as 2-bit types; ret is MSB, then arg0, arg1, etc
        } u_native;
    } data;
};

mp_raw_code_t *mp_emit_glue_new_raw_code(void) {
    mp_raw_code_t *rc = m_new0(mp_raw_code_t, 1);
    rc->kind = MP_CODE_RESERVED;
    return rc;
}

void mp_emit_glue_assign_bytecode(mp_raw_code_t *rc, const byte *code, mp_uint_t len,
    const mp_uint_t *const_table,
    #if MICROPY_PERSISTENT_CODE_SAVE
    uint16_t n_obj, uint16_t n_raw_code,
    #endif
    mp_uint_t scope_flags) {

    rc->kind = MP_CODE_BYTECODE;
    rc->scope_flags = scope_flags;
    rc->data.u_byte.bytecode = code;
    rc->data.u_byte.const_table = const_table;
    #if MICROPY_PERSISTENT_CODE_SAVE
    rc->data.u_byte.bc_len = len;
    rc->data.u_byte.n_obj = n_obj;
    rc->data.u_byte.n_raw_code = n_raw_code;
    #endif

#ifdef DEBUG_PRINT
    DEBUG_printf("assign byte code: code=%p len=" UINT_FMT " flags=%x\n", code, len, (uint)scope_flags);
#endif
#if MICROPY_DEBUG_PRINTERS
    if (mp_verbose_flag >= 2) {
        mp_bytecode_print(rc, code, len, const_table);
    }
#endif
}

#if MICROPY_EMIT_NATIVE || MICROPY_EMIT_INLINE_THUMB
void mp_emit_glue_assign_native(mp_raw_code_t *rc, mp_raw_code_kind_t kind, void *fun_data, mp_uint_t fun_len, const mp_uint_t *const_table, mp_uint_t n_pos_args, mp_uint_t scope_flags, mp_uint_t type_sig) {
    assert(kind == MP_CODE_NATIVE_PY || kind == MP_CODE_NATIVE_VIPER || kind == MP_CODE_NATIVE_ASM);
    rc->kind = kind;
    rc->scope_flags = scope_flags;
    rc->n_pos_args = n_pos_args;
    rc->data.u_native.fun_data = fun_data;
    rc->data.u_native.const_table = const_table;
    rc->data.u_native.type_sig = type_sig;

#ifdef DEBUG_PRINT
    DEBUG_printf("assign native: kind=%d fun=%p len=" UINT_FMT " n_pos_args=" UINT_FMT " flags=%x\n", kind, fun_data, fun_len, n_pos_args, (uint)scope_flags);
    for (mp_uint_t i = 0; i < fun_len; i++) {
        if (i > 0 && i % 16 == 0) {
            DEBUG_printf("\n");
        }
        DEBUG_printf(" %02x", ((byte*)fun_data)[i]);
    }
    DEBUG_printf("\n");

#ifdef WRITE_CODE
    FILE *fp_write_code = fopen("out-code", "wb");
    fwrite(fun_data, fun_len, 1, fp_write_code);
    fclose(fp_write_code);
#endif
#else
    (void)fun_len;
#endif
}
#endif

mp_obj_t mp_make_function_from_raw_code(mp_raw_code_t *rc, mp_obj_t def_args, mp_obj_t def_kw_args) {
    DEBUG_OP_printf("make_function_from_raw_code %p\n", rc);
    assert(rc != NULL);

    // def_args must be MP_OBJ_NULL or a tuple
    assert(def_args == MP_OBJ_NULL || MP_OBJ_IS_TYPE(def_args, &mp_type_tuple));

    // def_kw_args must be MP_OBJ_NULL or a dict
    assert(def_kw_args == MP_OBJ_NULL || MP_OBJ_IS_TYPE(def_kw_args, &mp_type_dict));

    // make the function, depending on the raw code kind
    mp_obj_t fun;
    switch (rc->kind) {
        case MP_CODE_BYTECODE:
        no_other_choice:
            fun = mp_obj_new_fun_bc(def_args, def_kw_args, rc->data.u_byte.bytecode, rc->data.u_byte.const_table);
            break;
        #if MICROPY_EMIT_NATIVE
        case MP_CODE_NATIVE_PY:
            fun = mp_obj_new_fun_native(def_args, def_kw_args, rc->data.u_native.fun_data, rc->data.u_native.const_table);
            break;
        case MP_CODE_NATIVE_VIPER:
            fun = mp_obj_new_fun_viper(rc->n_pos_args, rc->data.u_native.fun_data, rc->data.u_native.type_sig);
            break;
        #endif
        #if MICROPY_EMIT_INLINE_THUMB
        case MP_CODE_NATIVE_ASM:
            fun = mp_obj_new_fun_asm(rc->n_pos_args, rc->data.u_native.fun_data);
            break;
        #endif
        default:
            // raw code was never set (this should not happen)
            assert(0);
            goto no_other_choice; // to help flow control analysis
    }

    // check for generator functions and if so wrap in generator object
    if ((rc->scope_flags & MP_SCOPE_FLAG_GENERATOR) != 0) {
        fun = mp_obj_new_gen_wrap(fun);
    }

    return fun;
}

mp_obj_t mp_make_closure_from_raw_code(mp_raw_code_t *rc, mp_uint_t n_closed_over, const mp_obj_t *args) {
    DEBUG_OP_printf("make_closure_from_raw_code %p " UINT_FMT " %p\n", rc, n_closed_over, args);
    // make function object
    mp_obj_t ffun;
    if (n_closed_over & 0x100) {
        // default positional and keyword args given
        ffun = mp_make_function_from_raw_code(rc, args[0], args[1]);
    } else {
        // default positional and keyword args not given
        ffun = mp_make_function_from_raw_code(rc, MP_OBJ_NULL, MP_OBJ_NULL);
    }
    // wrap function in closure object
    return mp_obj_new_closure(ffun, n_closed_over & 0xff, args + ((n_closed_over >> 7) & 2));
}

#if MICROPY_PERSISTENT_CODE

#include "py/smallint.h"

// 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) \
    )

// 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;
}

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

#if MICROPY_PERSISTENT_CODE_LOAD

#include "py/parsenum.h"
#include "py/bc0.h"

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

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

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

STATIC qstr load_qstr(mp_reader_t *reader) {
    mp_uint_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
    mp_uint_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
    mp_uint_t n_obj = read_uint(reader);
    mp_uint_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 (mp_uint_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 (mp_uint_t i = 0; i < n_obj; ++i) {
        *ct++ = (mp_uint_t)load_obj(reader);
    }
    for (mp_uint_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, bc_len, 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 (strncmp((char*)header, "M\x00", 2) != 0) {
        nlr_raise(mp_obj_new_exception_msg(&mp_type_ValueError,
            "invalid .mpy file"));
    }
    if (header[2] != MPY_FEATURE_FLAGS || header[3] != mp_small_int_bits()) {
        nlr_raise(mp_obj_new_exception_msg(&mp_type_ValueError,
            "incompatible .mpy file"));
    }
    return load_raw_code(reader);
}

typedef struct _mp_mem_reader_t {
    const byte *cur;
    const byte *end;
} mp_mem_reader_t;

STATIC mp_uint_t mp_mem_reader_next_byte(void *br_in) {
    mp_mem_reader_t *br = br_in;
    if (br->cur < br->end) {
        return *br->cur++;
    } else {
        return (mp_uint_t)-1;
    }
}

mp_raw_code_t *mp_raw_code_load_mem(const byte *buf, size_t len) {
    mp_mem_reader_t mr = {buf, buf + len};
    mp_reader_t reader = {&mr, mp_mem_reader_next_byte};
    return mp_raw_code_load(&reader);
}

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

#if defined(__i386__) || defined(__x86_64__)
// unix file reader

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

typedef struct _mp_lexer_file_buf_t {
    int fd;
    byte buf[20];
    mp_uint_t len;
    mp_uint_t pos;
} mp_lexer_file_buf_t;

STATIC mp_uint_t file_buf_next_byte(void *fb_in) {
    mp_lexer_file_buf_t *fb = fb_in;
    if (fb->pos >= fb->len) {
        if (fb->len == 0) {
            return (mp_uint_t)-1;
        } else {
            int n = read(fb->fd, fb->buf, sizeof(fb->buf));
            if (n <= 0) {
                fb->len = 0;
                return (mp_uint_t)-1;
            }
            fb->len = n;
            fb->pos = 0;
        }
    }
    return fb->buf[fb->pos++];
}

mp_raw_code_t *mp_raw_code_load_file(const char *filename) {
    mp_lexer_file_buf_t fb;
    fb.fd = open(filename, O_RDONLY, 0644);
    int n = read(fb.fd, fb.buf, sizeof(fb.buf));
    fb.len = n;
    fb.pos = 0;
    mp_reader_t reader;
    reader.data = &fb;
    reader.read_byte = file_buf_next_byte;
    mp_raw_code_t *rc = mp_raw_code_load(&reader);
    close(fb.fd);
    return rc;
}

#elif defined(__thumb2__)
// fatfs file reader (assume thumb2 arch uses fatfs...)

#include "lib/fatfs/ff.h"

typedef struct _mp_lexer_file_buf_t {
    FIL fp;
    byte buf[20];
    uint16_t len;
    uint16_t pos;
} mp_lexer_file_buf_t;

STATIC mp_uint_t file_buf_next_byte(void *fb_in) {
    mp_lexer_file_buf_t *fb = fb_in;
    if (fb->pos >= fb->len) {
        if (fb->len < sizeof(fb->buf)) {
            return (mp_uint_t)-1;
        } else {
            UINT n;
            f_read(&fb->fp, fb->buf, sizeof(fb->buf), &n);
            if (n == 0) {
                return (mp_uint_t)-1;
            }
            fb->len = n;
            fb->pos = 0;
        }
    }
    return fb->buf[fb->pos++];
}

mp_raw_code_t *mp_raw_code_load_file(const char *filename) {
    mp_lexer_file_buf_t fb;
    /*FRESULT res =*/ f_open(&fb.fp, filename, FA_READ);
    UINT n;
    f_read(&fb.fp, fb.buf, sizeof(fb.buf), &n);
    fb.len = n;
    fb.pos = 0;

    mp_reader_t reader;
    reader.data = &fb;
    reader.read_byte = file_buf_next_byte;
    mp_raw_code_t *rc = mp_raw_code_load(&reader);

    f_close(&fb.fp);

    return rc;
}

#endif

#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, mp_uint_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';
        } else if (mp_obj_is_float(o)) {
            obj_type = 'f';
        } else {
            assert(MP_OBJ_IS_TYPE(o, &mp_type_complex));
            obj_type = 'c';
        }
        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) {
        nlr_raise(mp_obj_new_exception_msg(&mp_type_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', 0, MPY_FEATURE_FLAGS, mp_small_int_bits()};
    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__)

#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