# Copyright 2023 Oliver Smith
# SPDX-License-Identifier: GPL-3.0-or-later
# mypy: disable-error-code="attr-defined"
from pmb.core.context import get_context
from pmb.helpers import logging
from pmb.types import Apkbuild
import os
from pathlib import Path
import re
from collections import OrderedDict
from typing import Any

import pmb.config
from pmb.meta import Cache
import pmb.helpers.devices
from pmb.helpers.exceptions import NonBugError
import pmb.parse.version

# sh variable name regex: https://stackoverflow.com/a/2821201/3527128

# ${foo}
revar = re.compile(r"\${([a-zA-Z_]+[a-zA-Z0-9_]*)}")

# $foo
revar2 = re.compile(r"\$([a-zA-Z_]+[a-zA-Z0-9_]*)")

# ${var/foo/bar}, ${var/foo/}, ${var/foo} -- replace foo with bar
revar3 = re.compile(r"\${([a-zA-Z_]+[a-zA-Z0-9_]*)/([^/]+)(?:/([^/]*?))?}")

# ${foo#bar} -- cut off bar from foo from start of string
revar4 = re.compile(r"\${([a-zA-Z_]+[a-zA-Z0-9_]*)#(.*)}")

# foo=
revar5 = re.compile(r"([a-zA-Z_]+[a-zA-Z0-9_]*)=")


def replace_variable(apkbuild: Apkbuild, value: str) -> str:
    def log_key_not_found(match: re.Match) -> None:
        logging.verbose(
            f"{apkbuild['pkgname']}: key '{match.group(1)}' for"
            f" replacing '{match.group(0)}' not found, ignoring"
        )

    # ${foo}
    for match in revar.finditer(value):
        try:
            logging.verbose(
                "{}: replace '{}' with '{}'".format(
                    apkbuild["pkgname"], match.group(0), apkbuild[match.group(1)]
                )
            )
            value = value.replace(match.group(0), apkbuild[match.group(1)], 1)
        except KeyError:
            log_key_not_found(match)

    # $foo
    for match in revar2.finditer(value):
        try:
            newvalue = apkbuild[match.group(1)]
            logging.verbose(
                "{}: replace '{}' with '{}'".format(apkbuild["pkgname"], match.group(0), newvalue)
            )
            value = value.replace(match.group(0), newvalue, 1)
        except KeyError:
            log_key_not_found(match)

    # ${var/foo/bar}, ${var/foo/}, ${var/foo}
    for match in revar3.finditer(value):
        try:
            newvalue = apkbuild[match.group(1)]
            search = match.group(2)
            replacement = match.group(3)
            if replacement is None:  # arg 3 is optional
                replacement = ""
            newvalue = newvalue.replace(search, replacement, 1)
            logging.verbose(
                "{}: replace '{}' with '{}'".format(apkbuild["pkgname"], match.group(0), newvalue)
            )
            value = value.replace(match.group(0), newvalue, 1)
        except KeyError:
            log_key_not_found(match)

    # ${foo#bar}
    rematch4 = revar4.finditer(value)
    for match in rematch4:
        try:
            newvalue = apkbuild[match.group(1)]
            substr = match.group(2)
            if newvalue.startswith(substr):
                newvalue = newvalue.replace(substr, "", 1)
            logging.verbose(
                "{}: replace '{}' with '{}'".format(apkbuild["pkgname"], match.group(0), newvalue)
            )
            value = value.replace(match.group(0), newvalue, 1)
        except KeyError:
            log_key_not_found(match)

    return value


def function_body(path: Path, func: str) -> list[str]:
    """
    Get the body of a function in an APKBUILD.

    :param path: full path to the APKBUILD
    :param func: name of function to get the body of.
    :returns: function body in an array of strings.
    """
    func_body = []
    in_func = False
    lines = read_file(path)
    for line in lines:
        if in_func:
            if line.startswith("}"):
                in_func = False
                break
            func_body.append(line)
            continue
        else:
            if line.startswith(func + "() {"):
                in_func = True
                continue
    return func_body


def read_file(path: Path) -> list[str]:
    """
    Read an APKBUILD file

    :param path: full path to the APKBUILD
    :returns: contents of an APKBUILD as a list of strings
    """
    with path.open(encoding="utf-8") as handle:
        lines = handle.readlines()
        if handle.newlines != "\n":
            raise NonBugError(f"Wrong line endings in APKBUILD: {path}")
    return lines


def parse_next_attribute(
    lines: list[str], i: int, path: Path
) -> tuple[str, str, int] | tuple[None, None, int]:
    """
    Parse one attribute from the APKBUILD.

    It may be written across multiple lines, use a quoting sign and/or have
    a comment at the end. Some examples:

    pkgrel=3
    options="!check" # ignore this comment
    arch='all !armhf'
    depends="first-pkg
    second-pkg"

    :param lines: newline-terminated list of lines from the APKBUILD
    :param i: index of the line we are currently looking at
    :param path: full path to the APKBUILD (for error message)
    :returns: (attribute, value, i)
              attribute: attribute name if any was found in line i / None
              value: that was parsed from the line
              i: line that was parsed last
    """
    # Check for and cut off "attribute="
    rematch5 = revar5.match(lines[i])
    if not rematch5:
        return (None, None, i)
    attribute = rematch5.group(0)
    value = lines[i][len(attribute) : -1]
    attribute = rematch5.group(0).rstrip("=")

    # Determine end quote sign
    end_char = None
    for char in ["'", '"']:
        if value.startswith(char):
            end_char = char
            value = value[1:]
            break

    # Single line
    if not end_char:
        value = value.split("#")[0].rstrip()
        return (attribute, value, i)
    if end_char in value:
        value = value.split(end_char, 1)[0]
        return (attribute, value, i)

    # Parse lines until reaching end quote
    i += 1
    while i < len(lines):
        line = lines[i]
        value += " "
        if end_char in line:
            value += line.split(end_char, 1)[0].strip()
            return (attribute, value.strip(), i)
        value += line.strip()
        i += 1

    raise NonBugError(
        f"Can't find closing quote sign ({end_char}) for attribute '{attribute}' in: {path}"
    )


def _parse_attributes(
    path: Path, lines: list[str], apkbuild_attributes: dict[str, dict[str, bool]], ret: Apkbuild
) -> None:
    """
    Parse attributes from a list of lines. Variables are replaced with values
    from ret (if found) and split into the format configured in
    apkbuild_attributes.

    :param lines: the lines to parse
    :param apkbuild_attributes: the attributes to parse
    :param ret: a dict to update with new parsed variable
    """
    # Parse all variables first, and replace variables mentioned earlier
    for i in range(len(lines)):
        attribute, value, i = parse_next_attribute(lines, i, path)
        if not attribute or not value:
            continue
        ret[attribute] = replace_variable(ret, value)

    if "subpackages" in apkbuild_attributes:
        subpackages: OrderedDict[str, str] = OrderedDict()
        for subpkg in ret["subpackages"].split(" "):
            if subpkg:
                _parse_subpackage(path, lines, ret, subpackages, subpkg)
        ret["subpackages"] = subpackages

    # Split attributes
    for attribute, options in apkbuild_attributes.items():
        if options.get("array", False):
            # Split up arrays, delete empty strings inside the list
            ret[attribute] = list(filter(None, ret[attribute].split()))
        if options.get("int", False):
            if ret[attribute]:
                ret[attribute] = int(ret[attribute])
            else:
                ret[attribute] = 0

    # Remove variables not in attributes
    for attribute in list(ret.keys()):
        if attribute not in apkbuild_attributes:
            del ret[attribute]


def _parse_subpackage(
    path: Path, lines: list[str], apkbuild: Apkbuild, subpackages: dict[str, Any], subpkg: str
) -> None:
    """
    Attempt to parse attributes from a subpackage function.
    This will attempt to locate the subpackage function in the APKBUILD and
    update the given attributes with values set in the subpackage function.

    :param path: path to APKBUILD
    :param lines: the lines to parse
    :param apkbuild: dict of attributes already parsed from APKBUILD
    :param subpackages: the subpackages dict to update
    :param subpkg: the subpackage to parse
                   (may contain subpackage function name separated by :)
    """
    subpkgparts = subpkg.split(":")
    subpkgname = subpkgparts[0]
    subpkgsplit = subpkgname[subpkgname.rfind("-") + 1 :]
    # If there are multiple sections to the subpackage, the middle one (item 1 in the
    # sequence in this case) is the custom function name which we should use instead of
    # the deduced one. For example:
    #
    #   "$pkgname-something-subpkg:something_subpkg:noarch"
    #
    # But only actually use it if the custom function is not an empty string, as in
    # those cases it is not meant to be set here. For example:
    #
    #   "$pkgname-something::noarch"
    #
    if len(subpkgparts) > 1 and subpkgparts[1] != "":
        subpkgsplit = subpkgparts[1]

    # Find start and end of package function
    start = end = 0
    prefix = subpkgsplit + "() {"
    for i in range(len(lines)):
        if lines[i].startswith(prefix):
            start = i + 1
        elif start and lines[i].startswith("}"):
            end = i
            break

    if not start:
        # Unable to find subpackage function in the APKBUILD.
        # The subpackage function could be actually missing, or this is a
        # problem in the parser. For now we also don't handle subpackages with
        # default functions (e.g. -dev or -doc).
        # In the future we may want to specifically handle these, and throw
        # an exception here for all other missing subpackage functions.
        subpackages[subpkgname] = None
        logging.verbose(
            f"{apkbuild['pkgname']}: subpackage function '{subpkgsplit}' for "
            f"subpackage '{subpkgname}' not found, ignoring"
        )
        return

    if not end:
        raise NonBugError(
            f"Could not find end of subpackage function, no line starts with "
            f"'}}' after '{prefix}' in {path}"
        )

    lines = lines[start:end]
    # Strip tabs before lines in function
    lines = [line.strip() + "\n" for line in lines]

    # Copy variables
    apkbuild = apkbuild.copy()
    apkbuild["subpkgname"] = subpkgname
    # Don't inherit pmb_recommends from the top-level package.
    # There are two reasons for this:
    # 1) the subpackage may specify its own pmb_recommends
    # 2) the top-level package may list the subpackage as a pmb_recommends,
    #    thereby creating a circular dependency
    apkbuild["_pmb_recommends"] = ""

    # Parse relevant attributes for the subpackage
    _parse_attributes(path, lines, pmb.config.apkbuild_package_attributes, apkbuild)

    # Return only properties interesting for subpackages
    ret = {}
    for key in pmb.config.apkbuild_package_attributes:
        ret[key] = apkbuild[key]
    subpackages[subpkgname] = ret


def _apkbuild_from_lines(
    lines: list[str], path: Path, check_pkgver: bool = True, check_pkgname: bool = True
) -> Apkbuild:
    """
    See `apkbuild()` in this module for full explanation. This function exists
    as a means of avoiding reading the file twice if you already have the
    file parsed into this format.

    :param lines: lines of the APKBUILD, as parsed by `read_file()`.
    :param path: full path to the APKBUILD, for error messages.
    :param check_pkgver: verify that the pkgver is valid.
    :param check_pkgname: the pkgname must match the name of the aport folder
    :returns: relevant variables from the APKBUILD. Arrays get returned as
              arrays.
    """
    # Parse all attributes from the config
    ret = dict.fromkeys(pmb.config.apkbuild_attributes, "")
    _parse_attributes(path, lines, pmb.config.apkbuild_attributes, ret)

    # Sanity check: pkgname
    suffix = f"/{ret['pkgname']}/APKBUILD"
    if check_pkgname and not os.path.realpath(path).endswith(suffix):
        logging.info(f"Folder: '{os.path.dirname(path)}'")
        logging.info(f"Pkgname: '{ret['pkgname']}'")
        raise NonBugError(
            "The pkgname must be equal to the name of the folder that contains the APKBUILD!"
        )

    # Sanity check: pkgver
    if check_pkgver and not pmb.parse.version.validate(ret["pkgver"]):
        logging.info(
            "NOTE: Valid pkgvers are described here: "
            "https://wiki.alpinelinux.org/wiki/APKBUILD_Reference#pkgver"
        )
        raise NonBugError(f"Invalid pkgver '{ret['pkgver']}' in APKBUILD: {path}")

    return ret


@Cache("path")
def apkbuild(path: Path, check_pkgver: bool = True, check_pkgname: bool = True) -> Apkbuild:
    """
    Parse relevant information out of the APKBUILD file. This is not meant
    to be perfect and catch every edge case (for that, a full shell parser
    would be necessary!). Instead, it should just work with the use-cases
    covered by pmbootstrap and not take too long.
    Run 'pmbootstrap apkbuild_parse hello-world' for a full output example.

    :param path: full path to the APKBUILD
    :param check_pkgver: verify that the pkgver is valid.
    :param check_pkgname: the pkgname must match the name of the aport folder
    :returns: relevant variables from the APKBUILD. Arrays get returned as
              arrays.
    """
    if path.name != "APKBUILD":
        path = path / "APKBUILD"

    if not path.exists():
        raise FileNotFoundError(f"{path.relative_to(get_context().config.work)} not found!")

    # Read the file and check line endings
    lines = read_file(path)

    return _apkbuild_from_lines(lines, path, check_pkgver, check_pkgname)


def kernels(device: str) -> dict[str, str] | None:
    """
    Get the possible kernels from a device-* APKBUILD.

    :param device: the device name, e.g. "lg-mako"
    :returns: None when the kernel is hardcoded in depends
    :returns: kernel types and their description (as read from the subpackages)
              possible types: "downstream", "stable", "mainline"
              example: {"mainline": "Mainline description", "downstream": "Downstream description"}
    """
    # Read the APKBUILD
    apkbuild_path = pmb.helpers.devices.find_path(device, "APKBUILD")
    if apkbuild_path is None:
        return None
    subpackages = apkbuild(apkbuild_path)["subpackages"]

    # Read kernels from subpackages
    ret = {}
    subpackage_prefix = f"device-{device}-kernel-"
    for subpkgname, subpkg in subpackages.items():
        if not subpkgname.startswith(subpackage_prefix):
            continue
        if subpkg is None:
            raise NonBugError(f"Cannot find subpackage function for: {subpkgname}")
        name = subpkgname[len(subpackage_prefix) :]
        ret[name] = subpkg["pkgdesc"]

    # Return
    if ret:
        return ret
    return None


def _parse_comment_tags(lines: list[str], tag: str) -> list[str]:
    """
    Parse tags defined as comments in a APKBUILD file. This can be used to
    parse e.g. the maintainers of a package (defined using # Maintainer:).

    :param lines: lines of the APKBUILD
    :param tag: the tag to parse, e.g. Maintainer
    :returns: array of values of the tag, one per line
    """
    prefix = f"# {tag}:"
    return [line[len(prefix) :].strip() for line in lines if line.startswith(prefix)]


def maintainers(path: Path) -> list[str] | None:
    """
    Parse maintainers of an APKBUILD file. They should be defined using
    # Maintainer: (first maintainer) and # Co-Maintainer: (additional
    maintainers).

    :param path: full path to the APKBUILD
    :returns: array of (at least one) maintainer, or None
    """
    lines = read_file(path)
    apkbuild = _apkbuild_from_lines(lines, path, False, False)
    maintainers = []
    if maintainer := apkbuild.get("maintainer"):
        maintainers.append(maintainer)
    maintainers += _parse_comment_tags(lines, "Maintainer")

    match len(maintainers):
        case 0:
            return None
        case 1:
            pass
        case _:
            # An APKBUILD should only have one or zero maintainer comments or fields,
            # in pmaports others should be defined using Co-Maintainer:
            raise NonBugError('Multiple Maintainer: or maintainer="" lines in APKBUILD')

    maintainers += _parse_comment_tags(lines, "Co-Maintainer")
    if "" in maintainers:
        raise NonBugError("Empty (Co-)Maintainer: tag")
    return maintainers


def archived(path: Path) -> str | None:
    """
    Return if (and why) an APKBUILD might be archived. This should be
    defined using a # Archived: <reason> tag in the APKBUILD.

    :param path: full path to the APKBUILD
    :returns: reason why APKBUILD is archived, or None
    """
    archived = _parse_comment_tags(read_file(path), "Archived")
    if not archived:
        return None
    return "\n".join(archived)
