__all__ = [
    "load_metadata",
]


import os.path

from . import _benchmark, _pyproject_toml, _utils

METADATA = "pyproject.toml"
DEPENDENCIES = "requirements.in"
REQUIREMENTS = "requirements.txt"
DATA = "data"
RUN = "run_benchmark.py"

PEP_621_FIELDS = {
    "name": None,
    "version": None,
    "requires-python": "python",
    "dependencies": None,
    #'optional-dependencies': '',
    #'urls': '',
}
TOOL_FIELDS = {
    #'inherits': None,
    "metafile": None,
    "name": None,
    "tags": None,
    "datadir": None,
    "runscript": None,
    "extra_opts": None,
}


# class BenchmarkMetadata:
#    spec
#    base
#    metafile
#    tags
#    python
#    dependencies  # (from requirements.in)
#    requirements  # (from lock file or requirements.txt)
#    datadir
#    runscript
#    extra_opts


def load_metadata(metafile, defaults=None):
    if isinstance(metafile, str):
        name, rootdir = _name_from_filename(metafile)
        data, filename = _pyproject_toml.load_pyproject_toml(
            metafile,
            name=name or None,
            requirefiles=False,
        )
    else:
        text = metafile.read()
        filename = metafile.name
        name, rootdir = _name_from_filename(filename)
        data = _pyproject_toml.parse_pyproject_toml(
            text,
            rootdir,
            name,
            requirefiles=False,
        )
    project = data.get("project")
    tool = data.get("tool", {}).get("pyperformance", {})

    defaults = _ensure_defaults(defaults, rootdir)
    base, basefile = _resolve_base(
        tool.get("inherits"),  # XXX Pop it?
        project,
        filename,
        defaults,
    )
    top = _resolve(project or {}, tool, filename)
    merged = _merge_metadata(top, base, defaults)

    if not merged.get("name"):
        raise ValueError("missing benchmark name")
    if not merged.get("version"):
        print("====================")
        from pprint import pprint

        print("top:")
        pprint(top)
        print("base:")
        pprint(base)
        print("defaults:")
        pprint(defaults)
        print("merged:")
        pprint(merged)
        print("====================")
        raise ValueError("missing benchmark version")

    metafile = merged.pop("metafile")
    merged["spec"] = _benchmark.BenchmarkSpec(
        merged.pop("name"),
        merged.pop("version"),
        # XXX Should we leave this (origin) blank?
        metafile,
    )
    if basefile:
        merged["base"] = basefile

    return merged, filename


#######################################
# internal implementation


def _name_from_filename(metafile):
    rootdir, basename = os.path.split(metafile)
    if basename == "pyproject.toml":
        dirname = os.path.dirname(rootdir)
        name = dirname[3:] if dirname.startswith("bm_") else None
    elif basename.startswith("bm_") and basename.endswith(".toml"):
        name = basename[3:-5]
    else:
        name = None
    return name, rootdir


def _ensure_defaults(defaults, rootdir):
    if not defaults:
        defaults = {}

    if not defaults.get("datadir"):
        datadir = os.path.join(rootdir, DATA)
        if os.path.isdir(datadir):
            defaults["datadir"] = datadir

    if not defaults.get("runscript"):
        runscript = os.path.join(rootdir, RUN)
        if os.path.isfile(runscript):
            defaults["runscript"] = runscript

    return defaults


def _resolve_base(metabase, project, filename, defaults, *, minimalwithbase=False):
    rootdir, basename = os.path.split(filename)

    if not metabase:
        if basename == "pyproject.toml":
            return None, None
        elif not (basename.startswith("bm_") and basename.endswith(".toml")):
            return None, None
        elif not os.path.basename(rootdir).startswith("bm_"):
            return None, None
        else:
            metabase = os.path.join(rootdir, "pyproject.toml")
            if not os.path.isfile(metabase):
                return None, None

    if project is not None and minimalwithbase:
        unexpected = set(project) - {"name", "dynamic", "dependencies"}
        if unexpected:
            raise ValueError(
                f'[project] should be minimal if "inherits" is provided, got extra {sorted(unexpected)}'
            )

    if metabase == "..":
        metabase = os.path.join(
            os.path.dirname(rootdir),
            "base.toml",
        )
    if metabase == filename:
        raise Exception("circular")

    if not os.path.isabs(metabase):
        metabase = os.path.join(rootdir, metabase)
        if metabase == filename:
            raise Exception("circular")

    defaults = dict(defaults, name="_base_")
    return load_metadata(metabase, defaults)


def _resolve(project, tool, filename):
    resolved = {
        "metafile": filename,
    }

    rootdir = os.path.dirname(filename)
    for field, target in TOOL_FIELDS.items():
        if target is None:
            target = field
        if not resolved.get(target):
            value = tool.get(field)
            if value is not None:
                resolved[target] = _resolve_value(field, value, rootdir)

    for field, target in PEP_621_FIELDS.items():
        if target is None:
            target = field
        if field == "url":
            raise NotImplementedError
        elif not resolved.get(target):
            value = project.get(field)
            if value is not None:
                resolved[target] = value

    return resolved


def _resolve_value(field, value, rootdir):
    if field == "name":
        _utils.check_name(value, allownumeric=True)
    elif field == "metafile":
        assert False, "unreachable"
    elif field == "tags":
        if isinstance(value, str):
            value = value.replace(",", " ").split()
        for tag in value:
            _utils.check_name(tag)
            if tag == "all":
                raise ValueError("Invalid tag 'all'")
            elif tag == "":
                raise ValueError("Invalid empty tag")
    elif field == "datadir":
        if not os.path.isabs(value):
            value = os.path.join(rootdir, value)
        _utils.check_dir(value)
    elif field == "runscript":
        if not os.path.isabs(value):
            value = os.path.join(rootdir, value)
        _utils.check_file(value)
    elif field == "extra_opts":
        if isinstance(value, str):
            raise TypeError(f"extra_opts should be a list of strings, got {value!r}")
        for opt in value:
            if not opt or not isinstance(opt, str):
                raise TypeError(
                    f"extra_opts should be a list of strings, got {value!r}"
                )
    else:
        raise NotImplementedError(field)
    return value


def _merge_metadata(*tiers):
    merged = {}
    for data in tiers:
        if not data:
            continue
        for field, value in data.items():
            if field == "spec":
                field = "version"
                value = value.version
            if merged.get(field):
                # XXX Merge containers?
                continue
            if value or isinstance(value, int):
                merged[field] = value
    return merged