#!/usr/bin/env python3

import os
import re
import stat
import sys
import subprocess
from pathlib import Path
from tempfile import NamedTemporaryFile

# Matches e.g. "| [`bash`](bash/) | GNU Bash | 5.0 | https://www.gnu.org/software/bash/ |"
# and captures "bash" in group 1, "bash/" in group 2, "<spaces>" in group 3, "GNU Bash" in group 4, "5.0" in group 5
# and "https://www.gnu.org/software/bash/" in group 6.
PORT_TABLE_REGEX = re.compile(
    r'^\| \[`([^`]+)`\]\(([^\)]+)\)([^\|]+)\| ([^\|]+) \| ([^\|]+?) \| ([^\|]+) \|+$', re.MULTILINE
)

# Matches non-abbreviated git hashes
GIT_HASH_REGEX = re.compile(r'^[0-9a-f]{40}$')

PORT_TABLE_FILE = 'AvailablePorts.md'
IGNORE_FILES = {
    '.gitignore',
    '.port_include.sh',
    '.strip_env.sh',
    PORT_TABLE_FILE,
    'build_all.sh',
    'build_installed.sh',
    'README.md',
    '.hosted_defs.sh'
}

# Matches port names in Ports/foo/ReadMe.md
PORT_NAME_REGEX = re.compile(r'([ .()[\]{}\w-]+)\.patch')
REQUIRE_GIT_PATCHES = True
GIT_PATCH_SUBJECT_RE = re.compile(r'Subject: (.*)\n')


def read_port_table(filename):
    """Open a file and find all PORT_TABLE_REGEX matches.

    Args:
        filename (str): filename

    Returns:
        set: all PORT_TABLE_REGEX matches
    """
    ports = {}
    with open(filename, 'r') as fp:
        matches = PORT_TABLE_REGEX.findall(fp.read())
        for match in matches:
            line_len = sum([len(part) for part in match])
            ports[match[0]] = {
                "dir_ref": match[1],
                "name": match[2].strip(),
                "version": match[4].strip(),
                "url": match[5].strip(),
                "line_len": line_len
            }
    return ports


def read_port_dirs():
    """Check Ports directory for unexpected files and check each port has an executable package.sh file.

    Returns:
        list: all ports (set), no errors encountered (bool)
    """

    ports = {}
    all_good = True
    for entry in os.listdir():
        if entry in IGNORE_FILES:
            continue
        if not os.path.isdir(entry):
            print(f"Ports/{entry} is neither a port (not a directory) nor an ignored file?!")
            all_good = False
            continue
        if os.listdir(entry) == []:
            continue
        if not os.path.exists(entry + '/package.sh'):
            print(f"Ports/{entry}/ is missing its package.sh?!")
            all_good = False
            continue
        if not os.stat(entry + '/package.sh')[stat.ST_MODE] & stat.S_IXUSR:
            print(f"Ports/{entry}/package.sh is not executable?!")
            all_good = False
        ports[entry] = get_port_properties(entry)

    return ports, all_good


PORT_PROPERTIES = ('port', 'version', 'files')


def resolve_script_values(value: str, props: dict) -> str:
    """Resolve all ${...} values in a string.

    Args:
        value (str): string to resolve
        props (dict): dict of properties to resolve from

    Returns:
        str: resolved string
    """
    for match in re.finditer(r'\$\{([^}]+)\}', value):
        key = match.group(1)
        if key in props:
            value = value.replace(match.group(0), props[key])
    return value


def get_script_props(dir: str, script_name: str, props: dict, depth: int = 0, max_depth: int = 10) -> dict:
    """Parse a script file and return a dict of properties.

    Args:
        dir (str): root directory of script
        script_name (str): name of script to parse
        props (dict): dict of properties to resolve from
        depth (int): current depth of recursion
        max_depth (int): maximum depth of recursion

    Returns:
        dict: dict of properties
    """
    if depth > max_depth:
        print(f"Maximum recursion depth exceeded while parsing {dir}/{script_name}")
        return props

    buffer: str = ""
    for line in open(f"{dir}/{script_name}", 'r'):
        # Ignore comments (search in reverse to ignore # in strings)
        if line.rfind("#") > min(line.rfind('"'), line.rfind("'"), 0):
            line = line[0:line.rfind("#")]

        line = line.rstrip()
        buffer += line

        if "=" in buffer:
            [key, value] = buffer.split("=", 1)

            if (key.startswith(" ") or key.isspace()):
                buffer = ""
                continue

            if (value.startswith(('"', "'"))):
                if (value.endswith(value[0]) and len(value) > 1):
                    value = value[1:-1]
                else:
                    buffer += "\n"
                    continue

            props[key] = resolve_script_values(value, props)
            buffer = ""
        elif buffer.startswith('source'):
            resolved_path = resolve_script_values(buffer, props).split(' ', 1)[1]
            props = get_script_props(dir, resolved_path, props, depth + 1, max_depth)
            buffer = ""
        else:
            buffer = ""
    return props


def get_port_properties(port):
    """Retrieves common port properties from its package.sh file.

    Returns:
        dict: keys are values from PORT_PROPERTIES, values are from the package.sh file
    """
    props = get_script_props(port, 'package.sh', {})
    props = {prop: props[prop] if prop in props else '' for prop in PORT_PROPERTIES}
    return props


def check_package_files(ports):
    """Check port package.sh file for required properties.

    Args:
        ports (list): List of all ports to check

    Returns:
        bool: no errors encountered
    """

    all_good = True
    for port in ports.keys():
        package_file = f"{port}/package.sh"
        if not os.path.exists(package_file):
            continue
        props = ports[port]

        if props['port'] != port:
            print(f"Ports/{port} should use '{port}' for 'port' but is using '{props['port']}' instead")
            all_good = False

        for prop in PORT_PROPERTIES:
            if props[prop] == '':
                print(f"Ports/{port} is missing required property '{prop}'")
                all_good = False

    return all_good


def get_and_check_port_patch_list(ports):
    """Checks all port patches and returns the port list/properties

    Args:
        ports (list): List of all ports to check

    Returns:
        all_good (bool): No errors encountered
        all_properties (dict): Mapping of port to port properties
    """
    all_port_properties = {}
    all_good = True

    for port in ports:
        patches_directory = f"{port}/patches"

        if not os.path.exists(patches_directory):
            continue

        if not os.path.isdir(patches_directory):
            print(f"Ports/{port}/patches exists, but is not a directory. This is not right!")
            all_good = False
            continue

        patches_path = Path(patches_directory)
        patches_readme_path = patches_path / "ReadMe.md"
        patch_files = set(patches_path.glob("*.patch"))
        non_patch_files = set(patches_path.glob("*")) - patch_files - {patches_readme_path}

        port_properties = {
            "patches_path": patches_path,
            "patches_readme_path": patches_readme_path,
            "patch_files": patch_files,
            "non_patch_files": non_patch_files
        }
        all_port_properties[port] = port_properties

        if len(non_patch_files) != 0:
            print(f"Ports/{port}/patches contains the following non-patch files:",
                  ', '.join(x.name for x in non_patch_files))
            all_good = False

    return all_good, all_port_properties


def check_descriptions_for_port_patches(patches):
    """Ensure that ports containing patches have them documented.

    Args:
        patches (dict): Dictionary mapping ports to all their patches

    Returns:
        bool: no errors encountered
    """

    all_good = True
    for port, properties in patches.items():
        patches_readme_path = properties["patches_readme_path"]
        patch_files = properties["patch_files"]

        readme_file_exists = patches_readme_path.exists()
        if len(patch_files) == 0:
            print(f"Ports/{port}/patches exists, but contains no patches", end="")
            if readme_file_exists:
                print(", yet it contains a ReadMe.md")
            else:
                print()
            all_good = False
            continue

        if not readme_file_exists:
            print(f"Ports/{port}/patches contains patches but no ReadMe.md describing them")
            all_good = False
            continue

        with open(str(patches_readme_path), 'r', encoding='utf-8') as f:
            readme_contents = []
            for line in f:
                if not line.startswith('#'):
                    continue
                match = PORT_NAME_REGEX.search(line)
                if match:
                    readme_contents.append(match.group(1))

        patch_names = set(Path(x).stem for x in patch_files)

        for patch_name in patch_names:
            if patch_name not in readme_contents:
                print(f"Ports/{port}/patches/{patch_name}.patch does not appear to be described in"
                      " the corresponding ReadMe.md")
                all_good = False

        for patch_name in readme_contents:
            if patch_name not in patch_names:
                print(f"Ports/{port}/patches/{patch_name}.patch is described in ReadMe.md, "
                      "but does not actually exist")
                all_good = False

    return all_good


def try_parse_git_patch(path_to_patch):
    with open(path_to_patch, 'rb') as f:
        contents_of_patch = f.read()

    with NamedTemporaryFile('r+b') as message_file:
        res = subprocess.run(
            f"git mailinfo {message_file.name} /dev/null",
            shell=True,
            capture_output=True,
            input=contents_of_patch)

        if res.returncode != 0:
            return None

        message = message_file.read().decode('utf-8')
        subject = GIT_PATCH_SUBJECT_RE.search(res.stdout.decode("utf-8"))
        if subject:
            message = subject.group(1) + "\n" + message

        return message


def check_patches_are_git_patches(patches):
    """Ensure that all patches are patches made by (or compatible with) `git format-patch`.

    Args:
        patches (dict): Dictionary mapping ports to all their patches

    Returns:
        bool: no errors encountered
    """

    all_good = True

    for port, properties in patches.items():
        for patch_path in properties["patch_files"]:
            result = try_parse_git_patch(patch_path)
            if not result:
                print(f"Ports/{port}/patches: {patch_path.stem} does not appear to be a valid "
                      "git patch.")
                all_good = False
                continue
    return all_good


def check_available_ports(from_table, ports):
    """Check AvailablePorts.md for correct properties.

    Args:
        from_table (dict): Ports table from AvailablePorts.md
        ports (dict): Dictionary with port properties from package.sh

    Returns:
        bool: no errors encountered
    """

    all_good = True

    previous_line_len = None

    for port in from_table.keys():
        if previous_line_len is None:
            previous_line_len = from_table[port]["line_len"]
        if previous_line_len != from_table[port]["line_len"]:
            print(f"Table row for port {port} is improperly aligned with other rows.")
            all_good = False
        else:
            previous_line_len = from_table[port]["line_len"]

        actual_ref = from_table[port]["dir_ref"]
        expected_ref = f"{port}/"
        if actual_ref != expected_ref:
            print((
                f'Directory link target in AvailablePorts.md for port {port} is '
                f'incorrect, expected "{expected_ref}", found "{actual_ref}"'
            ))
            all_good = False

        actual_version = from_table[port]["version"]
        expected_version = ports[port]["version"]
        if GIT_HASH_REGEX.match(expected_version):
            expected_version = expected_version[0:7]
        if expected_version == "git":
            expected_version = ""
        if actual_version != expected_version:
            print((
                f'Version in AvailablePorts.md for port {port} is incorrect, '
                f'expected "{expected_version}", found "{actual_version}"'
            ))
            all_good = False

    return all_good


def run():
    """Check Ports directory and package files for errors."""

    from_table = read_port_table(PORT_TABLE_FILE)
    ports, all_good = read_port_dirs()

    from_table_set = set(from_table.keys())
    ports_set = set(ports.keys())

    if list(from_table.keys()) != sorted(from_table.keys(), key=str.lower):
        all_good = False
        print('AvailablePorts.md is not in the correct order, please ensure that all ports are sorted as follows:')
        for port in sorted(from_table.keys(), key=str.lower):
            print(f"    {port}")

    if from_table_set - ports_set:
        all_good = False
        print('AvailablePorts.md lists ports that do not appear in the file system:')
        for port in sorted(from_table_set - ports_set):
            print(f"    {port}")

    if ports_set - from_table_set:
        all_good = False
        print('AvailablePorts.md is missing the following ports:')
        for port in sorted(ports_set - from_table_set):
            print(f"    {port}")

    if not check_package_files(ports):
        all_good = False

    if not check_available_ports(from_table, ports):
        all_good = False

    patch_list_good, port_properties = get_and_check_port_patch_list(ports.keys())
    all_good = all_good and patch_list_good

    if not check_descriptions_for_port_patches(port_properties):
        all_good = False

    if REQUIRE_GIT_PATCHES and not check_patches_are_git_patches(port_properties):
        all_good = False

    if not all_good:
        sys.exit(1)

    print('No issues found.')


if __name__ == '__main__':
    os.chdir(f"{os.path.dirname(__file__)}/../Ports")
    run()