from typing import Optional, List
import unittest
import os
import glob
import shutil
import inspect
import pathlib

import pytest
import jinja2 as jj
from systemrdl import RDLCompiler

from .sv_line_anchor import SVLineAnchor

from peakrdl.regblock import RegblockExporter
from .cpuifs.base import CpuifTestMode
from .cpuifs.apb3 import APB3

from .simulators.modelsim import ModelSim


class RegblockTestCase(unittest.TestCase):
    #: Path to the testcase's RDL file.
    #: Relative to the testcase's dir. If unset, the first RDL file found in the
    #: testcase dir will be used
    rdl_file = None # type: Optional[str]

    #: RDL type name to elaborate. If unset, compiler will automatically choose
    #: the top.
    rdl_elab_target = None # type: Optional[str]

    #: Parameters to pass into RDL elaboration
    rdl_elab_params = {}

    #: Define what CPUIF to use for this testcase
    cpuif = APB3() # type: CpuifTestMode

    # Other exporter args:
    retime_read_fanin = False
    retime_read_response = False

    #: Abort test if it exceeds this number of clock cycles
    timeout_clk_cycles = 1000

    simulator_cls = ModelSim

    #: this gets auto-loaded via the _load_request autouse fixture
    request = None # type: pytest.FixtureRequest

    @pytest.fixture(autouse=True)
    def _load_request(self, request):
        self.request = request

    @classmethod
    def get_testcase_dir(cls) -> str:
        class_dir = os.path.dirname(inspect.getfile(cls))
        return class_dir

    @classmethod
    def get_build_dir(cls) -> str:
        this_dir = cls.get_testcase_dir()
        build_dir = os.path.join(this_dir, "run.out", cls.__name__)
        return build_dir

    @classmethod
    def _write_params(cls) -> None:
        """
        Write out the class parameters to a file so that it is easier to debug
        how a testcase was parameterized
        """
        path = os.path.join(cls.get_build_dir(), "params.txt")

        with open(path, 'w') as f:
            for k, v in cls.__dict__.items():
                if k.startswith("_") or callable(v):
                    continue
                f.write(f"{k}: {repr(v)}\n")


    @classmethod
    def _export_regblock(cls) -> RegblockExporter:
        """
        Call the peakrdl.regblock exporter to generate the DUT
        """
        this_dir = cls.get_testcase_dir()

        if cls.rdl_file:
            rdl_file = cls.rdl_file
        else:
            # Find any *.rdl file in testcase dir
            rdl_file = glob.glob(os.path.join(this_dir, "*.rdl"))[0]

        rdlc = RDLCompiler()
        rdlc.compile_file(rdl_file)
        root = rdlc.elaborate(cls.rdl_elab_target, "regblock", cls.rdl_elab_params)

        exporter = RegblockExporter()
        exporter.export(
            root,
            cls.get_build_dir(),
            module_name="regblock",
            package_name="regblock_pkg",
            cpuif_cls=cls.cpuif.cpuif_cls,
            retime_read_fanin=cls.retime_read_fanin,
            retime_read_response=cls.retime_read_response,
        )

        return exporter

    @classmethod
    def _generate_tb(cls, exporter: RegblockExporter):
        """
        Render the testbench template into actual tb.sv
        """
        template_root_path = os.path.join(os.path.dirname(__file__), "..")
        loader = jj.FileSystemLoader(
            template_root_path
        )
        jj_env = jj.Environment(
            loader=loader,
            undefined=jj.StrictUndefined,
            extensions=[SVLineAnchor],
        )

        context = {
            "cls": cls,
            "exporter": exporter,
        }

        # template path needs to be relative to the Jinja loader root
        template_path = os.path.join(cls.get_testcase_dir(), "tb_template.sv")
        template_path = os.path.relpath(template_path, template_root_path)
        template = jj_env.get_template(template_path)

        output_path = os.path.join(cls.get_build_dir(), "tb.sv")
        stream = template.stream(context)
        stream.dump(output_path)


    @classmethod
    def setUpClass(cls):
        # Create fresh build dir
        build_dir = cls.get_build_dir()
        if os.path.exists(build_dir):
            shutil.rmtree(build_dir)
        pathlib.Path(build_dir).mkdir(parents=True, exist_ok=True)

        cls._write_params()

        # Convert testcase RDL file --> SV
        exporter = cls._export_regblock()

        # Create testbench from template
        cls._generate_tb(exporter)

        simulator = cls.simulator_cls(testcase_cls=cls)

        # cd into the build directory
        cwd = os.getcwd()
        os.chdir(cls.get_build_dir())
        try:
            simulator.compile()
        finally:
            # cd back
            os.chdir(cwd)


    def setUp(self) -> None:
        # cd into the build directory
        self.original_cwd = os.getcwd()
        os.chdir(self.get_build_dir())


    def run_test(self, plusargs:List[str] = None) -> None:
        simulator = self.simulator_cls(testcase_cls_inst=self)
        simulator.run(plusargs)


    def tearDown(self) -> None:
        # cd back
        os.chdir(self.original_cwd)


    def assertSimLogPass(self, path: str):
        self.assertTrue(os.path.isfile(path))

        with open(path, encoding="utf-8") as f:
            for line in f:
                if line.startswith("# ** Error"):
                    self.fail(line)
                elif line.startswith("# ** Fatal"):
                    self.fail(line)