#!/usr/bin/env python
import sys
from collections import defaultdict

from messages_pb2 import (
    MessageType,
    wire_bootloader,
    wire_debug_in,
    wire_debug_out,
    wire_in,
    wire_no_fsm,
    wire_out,
)

fh = open("messages_map.h", "wt")
fl = open("messages_map_limits.h", "wt")

# len("MessageType_MessageType_") - len("_fields") == 17
TEMPLATE = "\t{{ {type} {dir} {msg_id:46} {fields:29} {process_func} }},\n"

LABELS = {
    wire_in: "in messages",
    wire_out: "out messages",
    wire_debug_in: "debug in messages",
    wire_debug_out: "debug out messages",
}

# interface-direction pairs
IFACE_DIR_PAIRS = {
    wire_in: ("n", "i"),
    wire_out: ("n", "o"),
    wire_debug_in: ("d", "i"),
    wire_debug_out: ("d", "o"),
}

SPECIAL_DEBUG_MESSAGES = {"MessageType_LoadDevice"}


def get_wire_extension(message):
    extensions = message.GetOptions().Extensions
    return next(ext for ext in IFACE_DIR_PAIRS if extensions[ext])


def handle_message(fh, fl, skipped, message):
    name = message.name
    short_name = name.split("MessageType_", 1).pop()
    assert short_name != name

    extension = get_wire_extension(message)
    interface, direction = IFACE_DIR_PAIRS[extension]

    for s in skipped:
        if short_name.startswith(s):
            return

    options = message.GetOptions()
    bootloader = options.Extensions[wire_bootloader]
    no_fsm = options.Extensions[wire_no_fsm]

    if getattr(options, "deprecated", None):
        fh.write("\t// Message %s is deprecated\n" % short_name)
        return
    if bootloader:
        fh.write("\t// Message %s is used in bootloader mode only\n" % short_name)
        return
    if no_fsm:
        fh.write("\t// Message %s is not used in FSM\n" % short_name)
        return

    if direction == "i":
        process_func = "(void (*)(const void *))fsm_msg%s" % short_name
    else:
        process_func = "0"

    fh.write(
        TEMPLATE.format(
            type="'%c'," % interface,
            dir="'%c'," % direction,
            msg_id="MessageType_%s," % name,
            fields="%s_fields," % short_name,
            process_func=process_func,
        )
    )

    encoded_size = None
    decoded_size = None
    t = interface + direction
    if t == "ni":
        encoded_size = "MSG_IN_ENCODED_SIZE"
        decoded_size = "MSG_IN_DECODED_SIZE"
    elif t == "no":
        encoded_size = "MSG_OUT_ENCODED_SIZE"
        decoded_size = "MSG_OUT_DECODED_SIZE"
    elif t == "do":
        encoded_size = "MSG_DEBUG_OUT_ENCODED_SIZE"
        decoded_size = "MSG_OUT_DECODED_SIZE"

    if encoded_size:
        fl.write(
            '_Static_assert(%s >= sizeof(%s_size), "msg buffer too small");\n'
            % (encoded_size, short_name)
        )

    if decoded_size:
        fl.write(
            '_Static_assert(%s >= sizeof(%s), "msg buffer too small");\n'
            % (decoded_size, short_name)
        )


skipped = sys.argv[1:]

fh.write(
    "\t// This file is automatically generated by messages_map.py -- DO NOT EDIT!\n"
)
fl.write(
    "// This file is automatically generated by messages_map.py -- DO NOT EDIT!\n\n"
)

messages = defaultdict(list)

for message in MessageType.DESCRIPTOR.values:
    if message.GetOptions().deprecated:
        continue
    extension = get_wire_extension(message)
    messages[extension].append(message)

for extension in (wire_in, wire_out, wire_debug_in, wire_debug_out):
    if extension == wire_debug_in:
        fh.write("\n#if DEBUG_LINK\n")
        fl.write("\n#if DEBUG_LINK\n")

    fh.write("\n\t// {label}\n\n".format(label=LABELS[extension]))

    for message in messages[extension]:
        if message.name in SPECIAL_DEBUG_MESSAGES:
            fh.write("#if DEBUG_LINK\n")
        handle_message(fh, fl, skipped, message)
        if message.name in SPECIAL_DEBUG_MESSAGES:
            fh.write("#endif\n")

    if extension == wire_debug_out:
        fh.write("\n#endif\n")
        fl.write("#endif\n")

fh.close()
fl.close()