# This file is part of the pycalver project
# https://gitlab.com/mbarkhau/pycalver
#
# Copyright (c) 2019 Manuel Barkhau (mbarkhau@gmail.com) - MIT License
# SPDX-License-Identifier: MIT
"""Parse setup.cfg or pycalver.cfg files."""

import os
import typing as typ
import logging
import datetime as dt
import configparser

import toml
import pathlib2 as pl

from . import version

logger = logging.getLogger("pycalver.config")

Patterns       = typ.List[str]
PatternsByGlob = typ.Dict[str, Patterns]

SUPPORTED_CONFIGS = ["setup.cfg", "pyproject.toml", "pycalver.toml"]


class ProjectContext(typ.NamedTuple):
    """Container class for project info."""

    path           : pl.Path
    config_filepath: pl.Path
    config_format  : str
    vcs_type       : typ.Optional[str]


def init_project_ctx(project_path: typ.Union[str, pl.Path, None] = ".") -> ProjectContext:
    """Initialize ProjectContext from a path."""
    if isinstance(project_path, pl.Path):
        path = project_path
    elif project_path is None:
        path = pl.Path(".")
    else:
        # assume it's a str/unicode
        path = pl.Path(project_path)

    if (path / "pycalver.toml").exists():
        config_filepath = path / "pycalver.toml"
        config_format   = 'toml'
    elif (path / "pyproject.toml").exists():
        config_filepath = path / "pyproject.toml"
        config_format   = 'toml'
    elif (path / "setup.cfg").exists():
        config_filepath = path / "setup.cfg"
        config_format   = 'cfg'
    else:
        # fallback to creating a new pycalver.toml
        config_filepath = path / "pycalver.toml"
        config_format   = 'toml'

    vcs_type: typ.Optional[str]

    if (path / ".git").exists():
        vcs_type = 'git'
    elif (path / ".hg").exists():
        vcs_type = 'hg'
    else:
        vcs_type = None

    return ProjectContext(path, config_filepath, config_format, vcs_type)


RawConfig = typ.Dict[str, typ.Any]


class Config(typ.NamedTuple):
    """Container for parameters parsed from a config file."""

    current_version: str
    version_pattern: str
    pep440_version : str

    commit: bool
    tag   : bool
    push  : bool

    file_patterns: PatternsByGlob


def _debug_str(cfg: Config) -> str:
    cfg_str_parts = [
        "Config Parsed: Config(",
        f"current_version='{cfg.current_version}'",
        "version_pattern='{pycalver}'",
        f"pep440_version='{cfg.pep440_version}'",
        f"commit={cfg.commit}",
        f"tag={cfg.tag}",
        f"push={cfg.push}",
        "file_patterns={",
    ]

    for filepath, patterns in cfg.file_patterns.items():
        for pattern in patterns:
            cfg_str_parts.append(f"\n    '{filepath}': '{pattern}'")

    cfg_str_parts += ["\n})"]
    return ", ".join(cfg_str_parts)


MaybeConfig    = typ.Optional[Config]
MaybeRawConfig = typ.Optional[RawConfig]

FilePatterns = typ.Dict[str, typ.List[str]]


def _parse_cfg_file_patterns(cfg_parser: configparser.RawConfigParser) -> FilePatterns:
    file_patterns: FilePatterns = {}

    file_pattern_items: typ.List[typ.Tuple[str, str]]
    if cfg_parser.has_section("pycalver:file_patterns"):
        file_pattern_items = cfg_parser.items("pycalver:file_patterns")
    else:
        file_pattern_items = []

    for filepath, patterns_str in file_pattern_items:
        patterns: typ.List[str] = []
        for line in patterns_str.splitlines():
            pattern = line.strip()
            if pattern:
                patterns.append(pattern)

        file_patterns[filepath] = patterns

    return file_patterns


class _ConfigParser(configparser.RawConfigParser):
    # pylint:disable=too-many-ancestors ; from our perspective, it's just one
    """Custom parser, simply to override optionxform behaviour."""

    def optionxform(self, optionstr: str) -> str:
        """Non-xforming (ie. uppercase preserving) override.

        This is important because our option names are actually
        filenames, so case sensitivity is relevant. The default
        behaviour is to do optionstr.lower()
        """
        return optionstr


OptionVal = typ.Union[str, bool, None]

BOOL_OPTIONS: typ.Mapping[str, OptionVal] = {'commit': False, 'tag': None, 'push': None}


def _parse_cfg(cfg_buffer: typ.IO[str]) -> RawConfig:
    cfg_parser = _ConfigParser()

    if hasattr(cfg_parser, 'read_file'):
        cfg_parser.read_file(cfg_buffer)
    else:
        cfg_parser.readfp(cfg_buffer)  # python2 compat

    if not cfg_parser.has_section("pycalver"):
        raise ValueError("Missing [pycalver] section.")

    raw_cfg: RawConfig = dict(cfg_parser.items("pycalver"))

    for option, default_val in BOOL_OPTIONS.items():
        val: OptionVal = raw_cfg.get(option, default_val)
        if isinstance(val, (bytes, str)):
            val = val.lower() in ("yes", "true", "1", "on")
        raw_cfg[option] = val

    raw_cfg['file_patterns'] = _parse_cfg_file_patterns(cfg_parser)

    return raw_cfg


def _parse_toml(cfg_buffer: typ.IO[str]) -> RawConfig:
    raw_full_cfg: typ.Any   = toml.load(cfg_buffer)
    raw_cfg     : RawConfig = raw_full_cfg.get('pycalver', {})

    for option, default_val in BOOL_OPTIONS.items():
        raw_cfg[option] = raw_cfg.get(option, default_val)

    return raw_cfg


def _normalize_file_patterns(raw_cfg: RawConfig) -> FilePatterns:
    """Create consistent representation of file_patterns.

    The result the same, regardless of the config format.
    """
    version_str    : str = raw_cfg['current_version']
    version_pattern: str = raw_cfg['version_pattern']
    pep440_version : str = version.to_pep440(version_str)

    file_patterns: FilePatterns
    if 'file_patterns' in raw_cfg:
        file_patterns = raw_cfg['file_patterns']
    else:
        file_patterns = {}

    for filepath, patterns in list(file_patterns.items()):
        if not os.path.exists(filepath):
            logger.warning(f"Invalid config, no such file: {filepath}")

        normalized_patterns: typ.List[str] = []
        for pattern in patterns:
            normalized_pattern = pattern.replace("{version}", version_pattern)
            if version_pattern == "{pycalver}":
                normalized_pattern = normalized_pattern.replace(
                    "{pep440_version}", "{pep440_pycalver}"
                )
            elif version_pattern == "{semver}":
                normalized_pattern = normalized_pattern.replace("{pep440_version}", "{semver}")
            elif "{pep440_version}" in pattern:
                logger.warning(f"Invalid config, cannot match '{pattern}' for '{filepath}'.")
                logger.warning(f"No mapping of '{version_pattern}' to '{pep440_version}'")
            normalized_patterns.append(normalized_pattern)

        file_patterns[filepath] = normalized_patterns

    return file_patterns


def _parse_config(raw_cfg: RawConfig) -> Config:
    """Parse configuration which was loaded from an .ini/.cfg or .toml file."""

    if 'current_version' not in raw_cfg:
        raise ValueError("Missing 'pycalver.current_version'")

    version_str: str = raw_cfg['current_version']
    version_str = raw_cfg['current_version'] = version_str.strip("'\" ")

    # TODO (mb 2020-09-06): new style pattern by default
    # version_pattern: str = raw_cfg.get('version_pattern', "vYYYY0M.BUILD[-TAG]")
    version_pattern: str = raw_cfg.get('version_pattern', "{pycalver}")
    version_pattern = raw_cfg['version_pattern'] = version_pattern.strip("'\" ")

    # NOTE (mb 2019-01-05): Provoke ValueError if version_pattern
    #   and current_version are not compatible.
    version.parse_version_info(version_str, version_pattern)

    pep440_version = version.to_pep440(version_str)

    commit = raw_cfg['commit']
    tag    = raw_cfg['tag']
    push   = raw_cfg['push']

    if tag is None:
        tag = raw_cfg['tag'] = False
    if push is None:
        push = raw_cfg['push'] = False

    if tag and not commit:
        raise ValueError("pycalver.commit = true required if pycalver.tag = true")

    if push and not commit:
        raise ValueError("pycalver.commit = true required if pycalver.push = true")

    file_patterns = _normalize_file_patterns(raw_cfg)

    cfg = Config(
        current_version=version_str,
        version_pattern=version_pattern,
        pep440_version=pep440_version,
        commit=commit,
        tag=tag,
        push=push,
        file_patterns=file_patterns,
    )
    logger.debug(_debug_str(cfg))
    return cfg


def _parse_current_version_default_pattern(cfg: Config, raw_cfg_text: str) -> str:
    is_pycalver_section = False
    for line in raw_cfg_text.splitlines():
        if is_pycalver_section and line.startswith("current_version"):
            return line.replace(cfg.current_version, cfg.version_pattern)

        if line.strip() == "[pycalver]":
            is_pycalver_section = True
        elif line and line[0] == "[" and line[-1] == "]":
            is_pycalver_section = False

    raise ValueError("Could not parse pycalver.current_version")


def parse(ctx: ProjectContext) -> MaybeConfig:
    """Parse config file if available."""
    if not ctx.config_filepath.exists():
        logger.warning(f"File not found: {ctx.config_filepath}")
        return None

    fobj: typ.IO[str]

    cfg_path: str
    if ctx.config_filepath.is_absolute():
        cfg_path = str(ctx.config_filepath.relative_to(ctx.path.absolute()))
    else:
        cfg_path = str(ctx.config_filepath)

    raw_cfg: RawConfig

    try:
        with ctx.config_filepath.open(mode="rt", encoding="utf-8") as fobj:
            if ctx.config_format == 'toml':
                raw_cfg = _parse_toml(fobj)
            elif ctx.config_format == 'cfg':
                raw_cfg = _parse_cfg(fobj)
            else:
                err_msg = "Invalid config_format='{ctx.config_format}'"
                raise RuntimeError(err_msg)

            cfg: Config = _parse_config(raw_cfg)

            if cfg_path not in cfg.file_patterns:
                fobj.seek(0)
                raw_cfg_text = fobj.read()
                cfg.file_patterns[cfg_path] = [
                    _parse_current_version_default_pattern(cfg, raw_cfg_text)
                ]

        return cfg
    except ValueError as ex:
        logger.warning(f"Couldn't parse {cfg_path}: {str(ex)}")
        return None


DEFAULT_CONFIGPARSER_BASE_TMPL = """
[pycalver]
current_version = "{initial_version}"
version_pattern = "{{pycalver}}"
commit = True
tag = True
push = True

[pycalver:file_patterns]
""".lstrip()


DEFAULT_CONFIGPARSER_SETUP_CFG_STR = """
setup.cfg =
    current_version = "{version}"
""".lstrip()


DEFAULT_CONFIGPARSER_SETUP_PY_STR = """
setup.py =
    "{version}"
    "{pep440_version}"
""".lstrip()


DEFAULT_CONFIGPARSER_README_RST_STR = """
README.rst =
    {version}
    {pep440_version}
""".lstrip()


DEFAULT_CONFIGPARSER_README_MD_STR = """
README.md =
    {version}
    {pep440_version}
""".lstrip()


DEFAULT_TOML_BASE_TMPL = """
[pycalver]
current_version = "{initial_version}"
version_pattern = "{{pycalver}}"
commit = true
tag = true
push = true

[pycalver.file_patterns]
""".lstrip()


DEFAULT_TOML_PYCALVER_STR = """
"pycalver.toml" = [
    'current_version = "{version}"',
]
""".lstrip()


DEFAULT_TOML_PYPROJECT_STR = """
"pyproject.toml" = [
    'current_version = "{version}"',
]
""".lstrip()


DEFAULT_TOML_SETUP_PY_STR = """
"setup.py" = [
    "{version}",
    "{pep440_version}",
]
""".lstrip()


DEFAULT_TOML_README_RST_STR = """
"README.rst" = [
    "{version}",
    "{pep440_version}",
]
""".lstrip()


DEFAULT_TOML_README_MD_STR = """
"README.md" = [
    "{version}",
    "{pep440_version}",
]
""".lstrip()


def _initial_version() -> str:
    return dt.datetime.now().strftime("v%Y%m.0001-alpha")


def _initial_version_pep440() -> str:
    return dt.datetime.now().strftime("%Y%m.1a0")


def default_config(ctx: ProjectContext) -> str:
    """Generate initial default config."""
    fmt = ctx.config_format
    if fmt == 'cfg':
        base_tmpl = DEFAULT_CONFIGPARSER_BASE_TMPL

        default_pattern_strs_by_filename = {
            "setup.cfg" : DEFAULT_CONFIGPARSER_SETUP_CFG_STR,
            "setup.py"  : DEFAULT_CONFIGPARSER_SETUP_PY_STR,
            "README.rst": DEFAULT_CONFIGPARSER_README_RST_STR,
            "README.md" : DEFAULT_CONFIGPARSER_README_MD_STR,
        }
    elif fmt == 'toml':
        base_tmpl = DEFAULT_TOML_BASE_TMPL

        default_pattern_strs_by_filename = {
            "pyproject.toml": DEFAULT_TOML_PYPROJECT_STR,
            "pycalver.toml" : DEFAULT_TOML_PYCALVER_STR,
            "setup.py"      : DEFAULT_TOML_SETUP_PY_STR,
            "README.rst"    : DEFAULT_TOML_README_RST_STR,
            "README.md"     : DEFAULT_TOML_README_MD_STR,
        }
    else:
        raise ValueError(f"Invalid config_format='{fmt}', must be either 'toml' or 'cfg'.")

    cfg_str = base_tmpl.format(initial_version=_initial_version())

    for filename, default_str in default_pattern_strs_by_filename.items():
        if (ctx.path / filename).exists():
            cfg_str += default_str

    has_config_file = any((ctx.path / fn).exists() for fn in SUPPORTED_CONFIGS)

    if not has_config_file:
        if ctx.config_format == 'cfg':
            cfg_str += DEFAULT_CONFIGPARSER_SETUP_CFG_STR
        if ctx.config_format == 'toml':
            cfg_str += DEFAULT_TOML_PYCALVER_STR

    cfg_str += "\n"

    return cfg_str


def write_content(ctx: ProjectContext) -> None:
    """Update project config file with initial default config."""
    fobj: typ.IO[str]

    cfg_content = default_config(ctx)
    if ctx.config_filepath.exists():
        cfg_content = "\n" + cfg_content

    with ctx.config_filepath.open(mode="at", encoding="utf-8") as fobj:
        fobj.write(cfg_content)
    print(f"Updated {ctx.config_filepath}")