# Copyright 2013 The Servo Project Developers. See the COPYRIGHT
# file at the top-level directory of this distribution.
#
# Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
# http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
# <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
# option. This file may not be copied, modified, or distributed
# except according to those terms.

import contextlib
import os
import fnmatch
import itertools
import re
import StringIO
import subprocess
import sys
from licenseck import licenses

filetypes_to_check = [".rs", ".rc", ".cpp", ".c", ".h", ".lock", ".py", ".toml", ".webidl"]
reftest_dir = "./tests/ref"
reftest_filetype = ".list"

ignored_files = [
    # Upstream
    os.path.join(".", "support", "*"),
    os.path.join(".", "tests", "wpt", "css-tests", "*"),
    os.path.join(".", "tests", "wpt", "harness", "*"),
    os.path.join(".", "tests", "wpt", "sync", "*"),
    os.path.join(".", "tests", "wpt", "sync_css", "*"),
    os.path.join(".", "tests", "wpt", "update", "*"),
    os.path.join(".", "tests", "wpt", "web-platform-tests", "*"),
    os.path.join(".", "python", "mach", "*"),
    os.path.join(".", "components", "script", "dom", "bindings", "codegen", "parser", "*"),
    os.path.join(".", "components", "script", "dom", "bindings", "codegen", "ply", "*"),
    os.path.join(".", "python", "_virtualenv", "*"),

    # Generated and upstream code combined with our own. Could use cleanup
    os.path.join(".", "target", "*"),
    os.path.join(".", "ports", "gonk", "src", "native_window_glue.cpp"),
    os.path.join(".", "ports", "cef", "*"),

    # MIT license
    os.path.join(".", "components", "util", "deque", "mod.rs"),

    # Hidden files/directories
    os.path.join(".", ".*"),
]


def should_check(file_name):
    if os.path.basename(file_name) == "Cargo.lock":
        return True
    if ".#" in file_name:
        return False
    if os.path.splitext(file_name)[1] not in filetypes_to_check:
        return False
    for pattern in ignored_files:
        if fnmatch.fnmatch(file_name, pattern):
            return False
    return True


def should_check_reftest(file_name):
    return file_name.endswith(reftest_filetype)


EMACS_HEADER = "/* -*- Mode:"
VIM_HEADER = "/* vim:"
MAX_LICENSE_LINESPAN = max(len(license.splitlines()) for license in licenses)


def check_license(file_name, lines):
    if file_name.endswith(".toml") or file_name.endswith(".lock"):
        raise StopIteration
    while lines and (lines[0].startswith(EMACS_HEADER) or lines[0].startswith(VIM_HEADER)):
        lines = lines[1:]
    contents = "".join(lines[:MAX_LICENSE_LINESPAN])
    valid_license = any(contents.startswith(license) for license in licenses)
    acknowledged_bad_license = "xfail-license" in contents
    if not (valid_license or acknowledged_bad_license):
        yield (1, "incorrect license")


def check_length(file_name, idx, line):
    if file_name.endswith(".lock"):
        raise StopIteration
    max_length = 120
    if len(line.rstrip('\n')) > max_length:
        yield (idx + 1, "Line is longer than %d characters" % max_length)


def check_whatwg_specific_url(idx, line):
    match = re.search(r"https://html\.spec\.whatwg\.org/multipage/[\w-]+\.html#([\w\:-]+)", line)
    if match is not None:
        preferred_link = "https://html.spec.whatwg.org/multipage/#{}".format(match.group(1))
        yield (idx + 1, "link to WHATWG may break in the future, use this format instead: {}".format(preferred_link))


def check_whatwg_single_page_url(idx, line):
    match = re.search(r"https://html\.spec\.whatwg\.org/#([\w\:-]+)", line)
    if match is not None:
        preferred_link = "https://html.spec.whatwg.org/multipage/#{}".format(match.group(1))
        yield (idx + 1, "links to WHATWG single-page url, change to multi page: {}".format(preferred_link))


def check_whitespace(idx, line):
    if line[-1] == "\n":
        line = line[:-1]
    else:
        yield (idx + 1, "no newline at EOF")

    if line.endswith(" "):
        yield (idx + 1, "trailing whitespace")

    if "\t" in line:
        yield (idx + 1, "tab on line")

    if "\r" in line:
        yield (idx + 1, "CR on line")


def check_by_line(file_name, lines):
    for idx, line in enumerate(lines):
        errors = itertools.chain(
            check_length(file_name, idx, line),
            check_whitespace(idx, line),
            check_whatwg_specific_url(idx, line),
            check_whatwg_single_page_url(idx, line),
        )

        for error in errors:
            yield error


def check_flake8(file_name, contents):
    from flake8.main import check_code

    if not file_name.endswith(".py"):
        raise StopIteration

    @contextlib.contextmanager
    def stdout_redirect(where):
        sys.stdout = where
        try:
            yield where
        finally:
            sys.stdout = sys.__stdout__

    ignore = {
        "W291",  # trailing whitespace; the standard tidy process will enforce no trailing whitespace
        "E501",  # 80 character line length; the standard tidy process will enforce line length
    }

    output = StringIO.StringIO()
    with stdout_redirect(output):
        check_code(contents, ignore=ignore)
    for error in output.getvalue().splitlines():
        _, line_num, _, message = error.split(":", 3)
        yield line_num, message.strip()


def check_lock(file_name, contents):
    def find_reverse_dependencies(dependency, version, content):
        dependency_prefix = "{} {}".format(dependency, version)
        for package in itertools.chain([content["root"]], content["package"]):
            for dependency in package.get("dependencies", []):
                if dependency.startswith(dependency_prefix):
                    yield package["name"]

    if not file_name.endswith(".lock"):
        raise StopIteration

    # package names to be neglected (as named by cargo)
    exceptions = ["libc", "cocoa"]

    import toml
    content = toml.loads(contents)

    packages = {}
    for package in content.get("package", []):
        packages.setdefault(package["name"], []).append(package["version"])

    for (name, versions) in packages.iteritems():
        if name in exceptions or len(versions) <= 1:
            continue

        highest = max(versions)
        for version in versions:
            if version != highest:
                reverse_dependencies = "\n".join(
                    "\t\t{}".format(n)
                    for n in find_reverse_dependencies(name, version, content)
                )
                substitutions = {
                    "package": name,
                    "old_version": version,
                    "new_version": highest,
                    "reverse_dependencies": reverse_dependencies
                }
                message = """
duplicate versions for package "{package}"
\t\033[93mfound dependency on version {old_version}\033[0m
\t\033[91mbut highest version is {new_version}\033[0m
\t\033[93mtry upgrading with\033[0m \033[96m./mach cargo-update -p {package}:{old_version}\033[0m
\tThe following packages depend on version {old_version}:
{reverse_dependencies}
""".format(**substitutions).strip()
                yield (1, message)


def maybe_int(value):
    try:
        return int(value)
    except ValueError:
        return value


def check_toml(file_name, lines):
    if not file_name.endswith(".toml"):
        raise StopIteration
    for idx, line in enumerate(lines):
        if line.find("*") != -1:
            yield (idx + 1, "found asterisk instead of minimum version number")


def check_rust(file_name, lines):
    if not file_name.endswith(".rs") or \
       file_name.endswith("properties.mako.rs") or \
       file_name.endswith(os.path.join("style", "build.rs")) or \
       file_name.endswith(os.path.join("unit", "style", "stylesheets.rs")):
        raise StopIteration
    comment_depth = 0
    merged_lines = ''

    import_block = False
    whitespace = False

    prev_use = None
    current_indent = 0
    prev_crate = {}
    prev_mod = {}

    decl_message = "{} is not in alphabetical order"
    decl_expected = "\n\t\033[93mexpected: {}\033[0m"
    decl_found = "\n\t\033[91mfound: {}\033[0m"

    for idx, original_line in enumerate(lines):
        # simplify the analysis
        line = original_line.strip()

        # Simple heuristic to avoid common case of no comments.
        if '/' in line:
            comment_depth += line.count('/*')
            comment_depth -= line.count('*/')

        if line.endswith('\\'):
            merged_lines += line[:-1]
            continue
        if comment_depth:
            merged_lines += line
            continue
        if merged_lines:
            line = merged_lines + line
            merged_lines = ''

        # Keep track of whitespace to enable checking for a merged import block
        #
        # Ignore attributes, comments, and imports
        if import_block:
            if not (line_is_comment(line) or line_is_attribute(line) or line.startswith("use ")):
                whitespace = line == ""

                if not whitespace:
                    import_block = False

        # get rid of strings and chars because cases like regex expression, keep attributes
        if not line_is_attribute(line):
            line = re.sub('".*?"|\'.*?\'', '', line)

        # get rid of comments
        line = re.sub('//.*?$|/\*.*?$|^\*.*?$', '', line)

        # get rid of attributes that do not contain =
        line = re.sub('^#[A-Za-z0-9\(\)\[\]_]*?$', '', line)

        # flag this line if it matches one of the following regular expressions
        # tuple format: (pattern, format_message, filter_function(match, line))
        no_filter = lambda match, line: True
        regex_rules = [
            (r",[^\s]", "missing space after ,", lambda match, line: '$' not in line),
            (r"[A-Za-z0-9\"]=", "missing space before =",
                lambda match, line: line_is_attribute(line)),
            (r"=[A-Za-z0-9\"]", "missing space after =",
                lambda match, line: line_is_attribute(line)),
            # ignore scientific notation patterns like 1e-6
            (r"[A-DF-Za-df-z0-9]-", "missing space before -",
                lambda match, line: not line_is_attribute(line)),
            (r"[A-Za-z0-9]([\+/\*%=])", "missing space before {0}",
                lambda match, line: (not line_is_attribute(line) and
                                     not is_associated_type(match, line))),
            # * not included because of dereferencing and casting
            # - not included because of unary negation
            (r'([\+/\%=])[A-Za-z0-9"]', "missing space after {0}",
                lambda match, line: (not line_is_attribute(line) and
                                     not is_associated_type(match, line))),
            (r"\)->", "missing space before ->", no_filter),
            (r"->[A-Za-z]", "missing space after ->", no_filter),
            (r"[^ ]=>", "missing space before =>", lambda match, line: match.start() != 0),
            (r"=>[^ ]", "missing space after =>", lambda match, line: match.end() != len(line)),
            (r"=>  ", "extra space after =>", no_filter),
            # ignore " ::crate::mod" and "trait Foo : Bar"
            (r" :[^:]", "extra space before :",
                lambda match, line: 'trait ' not in line[:match.start()]),
            # ignore "crate::mod" and ignore flagging macros like "$t1:expr"
            (r"[^:]:[A-Za-z]", "missing space after :",
                lambda match, line: '$' not in line[:match.end()]),
            (r"[A-Za-z0-9\)]{", "missing space before {", no_filter),
            # ignore cases like "{}", "}`", "}}" and "use::std::{Foo, Bar}"
            (r"[^\s{}]}[^`]", "missing space before }",
                lambda match, line: not re.match(r'^(pub )?use', line)),
            # ignore cases like "{}", "`{", "{{" and "use::std::{Foo, Bar}"
            (r"[^`]{[^\s{}]", "missing space after {",
                lambda match, line: not re.match(r'^(pub )?use', line)),
            # There should not be any extra pointer dereferencing
            (r": &Vec<", "use &[T] instead of &Vec<T>", no_filter),
            # No benefit over using &str
            (r": &String", "use &str instead of &String", no_filter),
        ]

        for pattern, message, filter_func in regex_rules:
            for match in re.finditer(pattern, line):
                if not filter_func(match, line):
                    continue
                yield (idx + 1, message.format(*match.groups(), **match.groupdict()))

        # check alphabetical order of extern crates
        if line.startswith("extern crate "):
            # strip "extern crate " from the begin and ";" from the end
            crate_name = line[13:-1]
            indent = len(original_line) - len(line)
            if indent not in prev_crate:
                prev_crate[indent] = ""
            if prev_crate[indent] > crate_name:
                yield(idx + 1, decl_message.format("extern crate declaration")
                      + decl_expected.format(prev_crate[indent])
                      + decl_found.format(crate_name))
            prev_crate[indent] = crate_name

        # imports must be in the same line, alphabetically sorted, and merged
        # into a single import block
        if line.startswith("use "):
            import_block = True
            indent = len(original_line) - len(line)
            if not line.endswith(";"):
                yield (idx + 1, "use statement spans multiple lines")
            # strip "use" from the begin and ";" from the end
            current_use = line[4:-1]
            if indent == current_indent and prev_use and current_use < prev_use:
                yield(idx + 1, decl_message.format("use statement")
                      + decl_expected.format(prev_use)
                      + decl_found.format(current_use))
            prev_use = current_use
            current_indent = indent

        if whitespace or not import_block:
            current_indent = 0

        # do not allow blank lines in an import block
        if import_block and whitespace and line.startswith("use "):
            whitespace = False
            yield(idx, "encountered whitespace following a use statement")

        # modules must be in the same line and alphabetically sorted
        if line.startswith("mod ") or line.startswith("pub mod "):
            indent = len(original_line) - len(line)
            # strip /(pub )?mod/ from the left and ";" from the right
            mod = line[4:-1] if line.startswith("mod ") else line[8:-1]

            if (idx - 1) < 0 or "#[macro_use]" not in lines[idx - 1]:
                match = line.find(" {")
                if indent not in prev_mod:
                    prev_mod[indent] = ""
                if match == -1 and not line.endswith(";"):
                    yield (idx + 1, "mod declaration spans multiple lines")
                if len(prev_mod[indent]) > 0 and mod < prev_mod[indent]:
                    yield(idx + 1, decl_message.format("mod declaration")
                          + decl_expected.format(prev_mod[indent])
                          + decl_found.format(mod))
                prev_mod[indent] = mod
        else:
            # we now erase previous entries
            prev_mod = {}


# Avoid flagging <Item=Foo> constructs
def is_associated_type(match, line):
    if match.group(1) != '=':
        return False
    open_angle = line[0:match.end()].rfind('<')
    close_angle = line[open_angle:].find('>') if open_angle != -1 else -1
    generic_open = open_angle != -1 and open_angle < match.start()
    generic_close = close_angle != -1 and close_angle + open_angle >= match.end()
    return generic_open and generic_close


def line_is_attribute(line):
    return re.search(r"#\[.*\]", line)


def line_is_comment(line):
    return re.search(r"^//|^/\*|^\*", line)


def check_webidl_spec(file_name, contents):
    # Sorted by this function (in pseudo-Rust). The idea is to group the same
    # organization together.
    # fn sort_standards(a: &Url, b: &Url) -> Ordering {
    #     let a_domain = a.domain().split(".");
    #     a_domain.pop();
    #     a_domain.reverse();
    #     let b_domain = b.domain().split(".");
    #     b_domain.pop();
    #     b_domain.reverse();
    #     for i in a_domain.into_iter().zip(b_domain.into_iter()) {
    #         match i.0.cmp(b.0) {
    #             Less => return Less,
    #             Greater => return Greater,
    #             _ => (),
    #         }
    #     }
    #     a_domain.path().cmp(b_domain.path())
    # }
    if not file_name.endswith(".webidl"):
        raise StopIteration
    standards = [
        "//www.khronos.org/registry/webgl/specs",
        "//developer.mozilla.org/en-US/docs/Web/API",
        "//dev.w3.org/2006/webapi",
        "//dev.w3.org/csswg",
        "//dev.w3.org/fxtf",
        "//dvcs.w3.org/hg",
        "//dom.spec.whatwg.org",
        "//domparsing.spec.whatwg.org",
        "//drafts.fxtf.org",
        "//encoding.spec.whatwg.org",
        "//html.spec.whatwg.org",
        "//url.spec.whatwg.org",
        "//xhr.spec.whatwg.org",
        "//w3c.github.io",
        "//heycam.github.io/webidl",
        # Not a URL
        "// This interface is entirely internal to Servo, and should not be" +
        " accessible to\n// web pages."
    ]
    for i in standards:
        if contents.find(i) != -1:
            raise StopIteration
    yield 0, "No specification link found."


def check_spec(file_name, lines):
    base_path = "components/script/dom/"
    if base_path not in file_name:
        raise StopIteration
    file_name = os.path.relpath(os.path.splitext(file_name)[0], base_path)
    patt = re.compile("^\s*\/\/.+")

    # Pattern representing a line with a macro
    macro_patt = re.compile("^\s*\S+!(.*)$")

    # Pattern representing a line with comment containing a spec link
    link_patt = re.compile("^\s*///? https://.+$")

    # Pattern representing a line with comment
    comment_patt = re.compile("^\s*///?.+$")

    pattern = "impl %sMethods for %s {" % (file_name, file_name)
    brace_count = 0
    in_impl = False
    for idx, line in enumerate(lines):
        if "// check-tidy: no specs after this line" in line:
            break
        if not patt.match(line):
            if pattern.lower() in line.lower():
                in_impl = True
            if ("fn " in line or macro_patt.match(line)) and brace_count == 1:
                for up_idx in range(1, idx + 1):
                    up_line = lines[idx - up_idx]
                    if link_patt.match(up_line):
                        # Comment with spec link exists
                        break
                    if not comment_patt.match(up_line):
                        # No more comments exist above, yield warning
                        yield (idx + 1, "method declared in webidl is missing a comment with a specification link")
                        break
            if '{' in line and in_impl:
                brace_count += 1
            if '}' in line and in_impl:
                if brace_count == 1:
                    break
                brace_count -= 1


def collect_errors_for_files(files_to_check, checking_functions, line_checking_functions):
    for filename in files_to_check:
        with open(filename, "r") as f:
            contents = f.read()
            for check in checking_functions:
                for error in check(filename, contents):
                    # the result will be: `(filename, line, message)`
                    yield (filename,) + error
            lines = contents.splitlines(True)
            for check in line_checking_functions:
                for error in check(filename, lines):
                    yield (filename,) + error


def check_reftest_order(files_to_check):
    for file_name in files_to_check:
        with open(file_name, "r") as fp:
            split_lines = fp.read().splitlines()
            lines = filter(lambda l: len(l) > 0 and l[0] != '#', split_lines)
            for idx, line in enumerate(lines[:-1]):
                next_line = lines[idx + 1]
                current = get_reftest_names(line)
                next = get_reftest_names(next_line)
                if current is not None and next is not None and current > next:
                    yield (file_name, split_lines.index(next_line) + 1, "line not in alphabetical order")


def get_reftest_names(line):
    tokens = line.split()
    if len(tokens) == 3:
        return tokens[1] + tokens[2]
    if len(tokens) == 4:
        return tokens[2] + tokens[3]
    return None


def get_html_file_names_from_reftest_list(reftest_dir, file_name):
    for line in open(os.path.join(reftest_dir, file_name), "r"):
        for token in line.split():
            if fnmatch.fnmatch(token, '*.html'):
                yield os.path.join(reftest_dir, token)


def check_reftest_html_files_in_basic_list(reftest_dir):
    basic_list_files = set(get_html_file_names_from_reftest_list(reftest_dir, "basic" + reftest_filetype))

    for file_name in os.listdir(reftest_dir):
        file_path = os.path.join(reftest_dir, file_name)
        if fnmatch.fnmatch(file_path, '*.html') and file_path not in basic_list_files:
            yield (file_path, "", "not found in basic.list")


def check_wpt_lint_errors():
    wpt_working_dir = os.path.abspath(os.path.join(".", "tests", "wpt", "web-platform-tests"))
    lint_cmd = os.path.join(wpt_working_dir, "lint")
    try:
        subprocess.check_call(lint_cmd, cwd=wpt_working_dir)  # Must run from wpt's working dir
    except subprocess.CalledProcessError as e:
        yield ("WPT Lint Tool", "", "lint error(s) in Web Platform Tests: exit status {0}".format(e.returncode))


def get_file_list(directory, only_changed_files=False):
    if only_changed_files:
        # only check the files that have been changed since the last merge
        args = ["git", "log", "-n1", "--author=bors-servo", "--format=%H"]
        last_merge = subprocess.check_output(args).strip()
        args = ["git", "diff", "--name-only", last_merge, directory]
        file_list = subprocess.check_output(args)
        # also check untracked files
        args = ["git", "ls-files", "--others", "--exclude-standard", directory]
        file_list += subprocess.check_output(args)
        return (os.path.join(".", f) for f in file_list.splitlines())
    else:
        return (os.path.join(r, f) for r, _, files in os.walk(directory) for f in files)


def scan(faster=False):
    # standard checks
    files_to_check = filter(should_check, get_file_list(".", faster))
    checking_functions = (check_flake8, check_lock, check_webidl_spec)
    line_checking_functions = (check_license, check_by_line, check_toml, check_rust, check_spec)
    errors = collect_errors_for_files(files_to_check, checking_functions, line_checking_functions)

    # reftest checks
    reftest_to_check = filter(should_check_reftest, get_file_list(reftest_dir, faster))
    r_errors = check_reftest_order(reftest_to_check)
    not_found_in_basic_list_errors = check_reftest_html_files_in_basic_list(reftest_dir)

    # wpt lint checks
    if faster:
        print "\033[93mUsing test-tidy \033[01m--faster\033[22m, skipping WPT lint\033[0m"
        wpt_lint_errors = iter([])
    else:
        wpt_lint_errors = check_wpt_lint_errors()

    # collect errors
    errors = itertools.chain(errors, r_errors, not_found_in_basic_list_errors, wpt_lint_errors)

    error = None
    for error in errors:
        print "\033[94m{}\033[0m:\033[93m{}\033[0m: \033[91m{}\033[0m".format(*error)

    if error is None:
        print "\033[92mtidy reported no errors.\033[0m"
        return 0
    else:
        return 1