#!/usr/bin/env python3

import sys
import argparse
import subprocess
import uuid
import xml.etree.ElementTree as ET


def run_faust(dsp_file, output_filename):
    """Run Faust on the DSP_FILE, write the output to OUTPUT_FILENAME, and return the parsed XML tree of the description file."""
    with open(output_filename, "w") as outfile:
        result = subprocess.run(
            [
                "faust",
                "-xml",  # generate description
                "-lang",
                "c",  # C code, please
                "-scal",  # non-vectorized code
                "-light",  # keep it light
                "-a",
                "faust-ksoloti-object.c",  # architecture file
                dsp_file,
            ],
            stdout=outfile,
            check=True,
        )
    return result


def process_sliders(xml):
    """Process sliders and return inlets, params, and conversions."""
    inlets = ""
    params = ""
    output = ""
    widgets = xml.findall(".//ui/activewidgets/widget[@type='hslider']")
    for widget in widgets:
        varname = widget.find("varname").text
        label = widget.find("label").text
        max = widget.find("max").text
        maybe_unit = widget.find("meta[@key='unit']")
        pitch = isinstance(maybe_unit, ET.Element) and maybe_unit.text == "Hz"

        if pitch:
            param_type = "frac32.s.map.pitch"
        else:
            param_type = "frac32.u.map"

        inlets += f'<frac32 name="{label}" />\n'
        params += f'<{param_type} name="{label}" />\n'

        # TODO: summation and conversion based on type
        if pitch:
            output += (
                f"uint32_t {label} = mtof48k_ext_q31(param_{label} + inlet_{label});\n"
            )
        else:
            output += f"uint32_t {label} = param_{label} + inlet_{label};\n"
        output += f"mdsp.{varname} = fminf(1.0f, q27_to_float({label})) * {max};\n"
    return (inlets, params, output)


def safe_extract_text(xml, xpath, alternative):
    result = xml.find(xpath)
    if isinstance(result, ET.Element):
        return result.text
    else:
        return alternative


def massage_output(oldfile, newfile, xml):
    """
    Process the Faust output.
    """

    # - throw everything before <objdefs> away
    # - throw everything after </objdefs> away
    # - remove extern "C" chunk (wrapped in "#ifdef __cplusplus")
    # - inject params and inlets
    # - replace scaling factors for sliders
    # - replace metadata

    id = uuid.uuid4()
    author = safe_extract_text(xml, "./author", "unknown")
    name = safe_extract_text(xml, "./name", "unnamed")
    license = safe_extract_text(xml, "./license", "CC-SA 4.0")
    description = safe_extract_text(
        xml, "./description", "Generated from Faust DSP code."
    )

    inlets, params, conversions = process_sliders(xml)

    seen_start = False
    seen_end = False
    skip_ifdef = False

    replacements = {
        "UUID": str(id),
        "AUTHOR": author,
        "NAME": name,
        "LICENSE": license,
        "DESCRIPTION": description,
        "INLETS": inlets,
        "PARAMS": params,
        "SLIDERS": conversions,
    }

    with open(oldfile, "r", encoding="utf-8") as infile, open(
        newfile, "w", encoding="utf-8"
    ) as outfile:
        for line in infile:
            if not seen_start and line.startswith("<objdefs>"):
                seen_start = True
            if not seen_end and line.startswith("</objdefs>"):
                seen_end = True
            if seen_end:
                outfile.write(line)
                return

            if seen_start:
                if line.startswith("#ifdef __cplusplus"):
                    skip_ifdef = True

                if skip_ifdef:
                    if line.startswith("#endif"):
                        skip_ifdef = False
                    continue

                for key, value in replacements.items():
                    if "<<" + key + ">>" in line:
                        line = line.replace("<<" + key + ">>", value)

                outfile.write(line)
            else:
                continue


def main(faust_input_file, axo_output_file):
    axo_temp_output_file = axo_output_file + ".temp"
    run_faust(faust_input_file, axo_temp_output_file)

    # Parse generated XML description
    dsp_xml = faust_input_file + ".xml"
    xml = ET.parse(dsp_xml).getroot()

    # Modify Axoloti object file
    massage_output(axo_temp_output_file, axo_output_file, xml)


def arguments():
    parser = argparse.ArgumentParser()
    parser.add_argument("-i", "--input", type=str, required=True)
    parser.add_argument("-o", "--output", type=str, required=True)
    return parser.parse_args()


if __name__ == "__main__":
    args = arguments()
    main(args.input, args.output)