import re
import sys
import cantools

def parse_dbc_file(file_path):
    signals = []
    current_message = None
    try:
        with open(file_path, 'r', encoding='cp1252') as f:
            lines = f.readlines()
        print(f"[INFO] Read {len(lines)} lines from DBC file.")

        start_parsing = False
        for line in lines:
            line = line.strip()
            if not line:
                continue

            if not start_parsing:
                if line.startswith("BO_"):
                    start_parsing = True
                else:
                    continue

            if line.startswith("BO_"):
                if current_message and current_message["signals"]:
                    signals.append(current_message)
                    print(f"[INFO] Added message: {current_message['name']} with {len(current_message['signals'])} signals.")

                parts = line.split()
                if len(parts) < 5:
                    print(f"[WARNING] Skipping malformed BO_ line: {line}")
                    continue

                current_message = {
                    "id": parts[1],
                    "name": parts[2].replace(":", ""),
                    "dlc": parts[3],
                    "transmitter": parts[4],
                    "signals": []
                }
                print(f"[INFO] Found message: {current_message['name']}")

            elif line.startswith("SG_") and current_message:
                try:
                    parts = line.split(":")
                    if len(parts) < 2:
                        print(f"[WARNING] Skipping malformed SG_ line: {line}")
                        continue

                    signal_name = parts[0].split()[1].strip()
                    bit_info = parts[1].split()[0]
                    receiver = parts[1].split()[-1]

                    if receiver != "VCU":
                        continue

                    byte_offset, rest = bit_info.split("|")
                    bit_offset = int(rest.split("@")[0])
                    size = int(re.search(r'\d+', rest.split("@")[0]).group())
                    factor_offset_match = re.search(r'\(([^)]+)\)', line)
                    if not factor_offset_match:
                        print(f"[WARNING] Skipping signal with missing factor/offset: {line}")
                        continue

                    factor_offset = factor_offset_match.group(1).split(",")
                    factor = float(factor_offset[0])
                    offset = float(factor_offset[1])

                    current_message["signals"].append({
                        "name": signal_name,
                        "byte_offset": int(byte_offset) // 8,
                        "bit_offset": bit_offset,
                        "size": size,
                        "factor": factor,
                        "offset": offset,
                        "signed": '-' in rest.split("@")[1]
                    })
                    print(f"[INFO] Added signal: {signal_name}")
                except (ValueError, IndexError, AttributeError) as e:
                    print(f"[ERROR] Error parsing signal: {line}, {e}")
                    continue

        if current_message and current_message["signals"]:
            signals.append(current_message)
            print(f"[INFO] Added last message: {current_message['name']} with {len(current_message['signals'])} signals.")

    except Exception as e:
        print(f"[ERROR] Error while parsing DBC file: {e}")
        return []

    print(f"[INFO] Parsed {len(signals)} messages.")
    return signals


def generate_vcu_rx_function_with_factors(dbc_path, output_file):
    # Load the DBC file
    db = cantools.database.load_file(dbc_path)

    # Initialize the header of the C file
    c_file_content = """
#include "can.h"

// Declare Factors and Offsets for signals
"""

    # Collect unique Factors and Offsets
    factors_offsets = {}
    for message in db.messages:
        if "VCU" in message.receivers:
            for signal in message.signals:
                factor_name = f"Factor_{str(signal.scale).replace('.', '_')}"
                offset_name = f"Offset_m_{abs(signal.offset):.0f}"
                if signal.scale != 1:
                    factors_offsets[factor_name] = signal.scale
                if signal.offset != 0:
                    factors_offsets[offset_name] = signal.offset

    # Add Factor and Offset variable declarations
    for name, value in factors_offsets.items():
        c_file_content += f"const float {name} = {value};\n"

    # Add a newline for separation
    c_file_content += "\n"

    # Iterate through all messages in the DBC file
    for message in db.messages:
        # Check if "VCU" is in the receivers list
        if "VCU" in message.receivers:
            # Define the temporary struct
            temp_struct_name = f"CH0_MV1_0x{message.frame_id:X}_temp"
            c_file_content += f"""
void Receive_{message.name}_CH0_0x{message.frame_id:X}(void)
{{
    struct {{
"""

            # Add temporary variables to the struct
            for signal in message.signals:
                if signal.is_signed:
                    signal_type = "signed int"
                else:
                    signal_type = "unsigned int"
                c_file_content += f"        {signal_type} {signal.name}_temp : {signal.length};\n"

            c_file_content += f"    }} {temp_struct_name};\n\n"

            # Add temp assignments
            for signal in message.signals:
                start_byte = signal.start // 8
                start_bit = signal.start % 8
                signal_length = signal.length
                shift_expr = f"(CAN_ch[0].rx.buf[{start_byte}] >> shift{start_bit})"
                if signal_length > 8:
                    # Handle multi-byte signals
                    multi_byte_expr = []
                    for i in range((signal_length + 7) // 8):
                        byte_shift = i * 8
                        if i == 0:
                            multi_byte_expr.append(f"(CAN_ch[0].rx.buf[{start_byte + i}] >> shift{start_bit})")
                        else:
                            multi_byte_expr.append(f"(CAN_ch[0].rx.buf[{start_byte + i}] << shift{byte_shift})")
                    shift_expr = " | ".join(multi_byte_expr)
                c_file_content += f"    {temp_struct_name}.{signal.name}_temp = ({shift_expr}) & _{signal_length}bit;\n"

            c_file_content += "\n"

            # Assign to final ECU variables
            for signal in message.signals:
                factor_name = f"Factor_{str(signal.scale).replace('.', '_')}"
                offset_name = f"Offset_m_{abs(signal.offset):.0f}"
                factor = f" * {factor_name}" if signal.scale != 1 else ""
                offset = f" + {offset_name}" if signal.offset != 0 else ""
                temp_var = f"{temp_struct_name}.{signal.name}_temp"
                if signal.is_signed:
                    c_file_content += f"    ECU3.RX.CH0_{message.name}_0x{message.frame_id:X}.{signal.name} = ({temp_var}{factor}){offset};\n"
                else:
                    c_file_content += f"    ECU3.RX.CH0_{message.name}_0x{message.frame_id:X}.{signal.name} = {temp_var}{factor}{offset};\n"

            c_file_content += "}\n"

    # Write the generated code to a single C file
    with open(output_file, "w") as c_file:
        c_file.write(c_file_content)
    print(f"Generated RX function C file with Factors and Offsets: {output_file}")


def generate_input_functions(signals, output_file):
    if not signals:
        print("[WARNING] No signals to generate Input functions for.")
        return

    with open(output_file, 'w') as f:
        for message in signals:
            hex_id = f"0x{int(message['id']):X}"
            function_name = f"void Input_Data_Set_{message['name']}_CH0_{hex_id}(void)"
            f.write(f"{function_name}\n{{\n")
            for signal in message["signals"]:
                f.write(f"    GV_{signal['name']} = ECU3.RX.CH0_RX_{message['name']}_{hex_id}.{signal['name']};\n")
            f.write("}\n\n")
    print(f"[INFO] Input functions written to {output_file}")


def generate_structs(signals, output_file):
    if not signals:
        print("[WARNING] No signals to generate structs for.")
        return

    with open(output_file, 'w') as f:
        f.write("#ifndef GENERATED_STRUCTS_H\n")
        f.write("#define GENERATED_STRUCTS_H\n\n")
        f.write("#include <stdint.h>\n\n")

        for message in signals:
            hex_id = f"0x{int(message['id']):X}"
            f.write(f"typedef struct\n{{\n")
            for signal in message["signals"]:
                if signal["size"] <= 32:
                    f.write(f"    uint32_t {signal['name']} : {signal['size']};\n")
                else:
                    f.write(f"    float {signal['name']};\n")
            f.write(f"}} CH0_RX_{message['name']}_{hex_id};\n\n")
        f.write("#endif // GENERATED_STRUCTS_H\n")
    print(f"[INFO] Structs written to {output_file}")


def generate_globals(signals, output_file, header_file):
    if not signals:
        print("[WARNING] No signals to generate globals for.")
        return

    with open(output_file, 'w') as f:
        f.write("#include <generated_globals.h>\n")
        
        for message in signals:
            for signal in message["signals"]:
                if signal["size"] > 32:
                    f.write(f"float GV_{signal['name']} = 0.0f;\n")
                else:
                    f.write(f"uint32_t GV_{signal['name']} = 0;\n")

    with open(header_file, 'w') as f:
        f.write("#ifndef GENERATED_GLOBALS_H\n")
        f.write("#define GENERATED_GLOBALS_H\n\n")
        f.write("#include <stdint.h>\n\n")
        for message in signals:
            for signal in message["signals"]:
                if signal["size"] > 32:
                    f.write(f"extern float GV_{signal['name']};\n")
                else:
                    f.write(f"extern uint32_t GV_{signal['name']};\n")
        f.write("\n#endif // GENERATED_GLOBALS_H\n")
    print(f"[INFO] Globals and extern declarations written to {output_file} and {header_file}")


def generate_initialization(signals, output_file):
    if not signals:
        print("[WARNING] No signals to generate initialization for.")
        return

    with open(output_file, 'w') as f:
        f.write("void ECU3_Data_Init(void)\n{\n")
        for message in signals:
            hex_id = f"0x{int(message['id']):X}"
            struct_prefix = f"ECU3.RX.CH0_RX_{message['name']}_{hex_id}"
            for signal in message["signals"]:
                if signal["offset"] != 0.0:
                    if signal["size"] <= 32:
                        f.write(f"    {struct_prefix}.{signal['name']} = {signal['offset']};\n")
                    else:
                        f.write(f"    {struct_prefix}.{signal['name']} = {signal['offset']}f;\n")
                else:
                    if signal["size"] <= 32:
                        f.write(f"    {struct_prefix}.{signal['name']} = 0;\n")
                    else:
                        f.write(f"    {struct_prefix}.{signal['name']} = 0.0f;\n")
            f.write("\n")
        f.write("}\n")
    print(f"[INFO] Initialization function written to {output_file}")


if __name__ == "__main__":
    dbc_file_path = sys.argv[1]
    output_c_file = "C:/Users/MSI/Desktop/DB/generated_receive.c"
    output_input_file = "C:/Users/MSI/Desktop/DB/generated_input.c"
    output_structs_file = "C:/Users/MSI/Desktop/DB/generated_structs.h"
    output_globals_file = "C:/Users/MSI/Desktop/DB/generated_globals.c"
    output_globals_header = "C:/Users/MSI/Desktop/DB/generated_globals.h"
    output_initialization_file = "C:/Users/MSI/Desktop/DB/generated_init.c"

    signals = parse_dbc_file(dbc_file_path)
    generate_vcu_rx_function_with_factors(dbc_file_path, output_c_file)
    generate_input_functions(signals, output_input_file)
    generate_structs(signals, output_structs_file)
    generate_globals(signals, output_globals_file, output_globals_header)
    generate_initialization(signals, output_initialization_file)