# This Source Code Form is subject to the terms of the Mozilla Public
# License, v. 2.0. If a copy of the MPL was not distributed with this
# file, You can obtain one at http://mozilla.org/MPL/2.0/.

import cStringIO
import hashlib
import os
import platform
import subprocess
import urllib2
import zipfile
from distutils import spawn
from symFileManager import SymFileManager
from symbolicationRequest import SymbolicationRequest
from symLogging import LogMessage

"""
Symbolication is broken when using type 'str' in python 2.7, so we use 'basestring'.
But for python 3.0 compatibility, 'basestring' isn't defined, but the 'str' type works.
So we force 'basestring' to 'str'.
"""
try:
    basestring
except NameError:
    basestring = str


class SymbolError(Exception):
    pass


class OSXSymbolDumper:

    def __init__(self):
        self.dump_syms_bin = os.path.join(
            os.path.dirname(__file__), 'dump_syms_mac')
        if not os.path.exists(self.dump_syms_bin):
            raise SymbolError("No dump_syms_mac binary in this directory")

    def store_symbols(self, lib_path, expected_breakpad_id,
                      output_filename_without_extension):
        """
        Returns the filename at which the .sym file was created, or None if no
        symbols were dumped.
        """
        output_filename = output_filename_without_extension + ".sym"

        def get_archs(filename):
            """
            Find the list of architectures present in a Mach-O file.
            """
            return subprocess.Popen(["lipo", "-info", filename],
                                    stdout=subprocess.PIPE)\
                .communicate()[0].split(':')[2].strip().split()

        def process_file(arch):
            proc = subprocess.Popen([self.dump_syms_bin, "-a", arch, lib_path],
                                    stdout=subprocess.PIPE,
                                    stderr=subprocess.PIPE)
            stdout, stderr = proc.communicate()
            if proc.returncode != 0:
                return None

            module = stdout.splitlines()[0]
            bits = module.split(' ', 4)
            if len(bits) != 5:
                return None
            _, platform, cpu_arch, actual_breakpad_id, debug_file = bits

            if actual_breakpad_id != expected_breakpad_id:
                return None

            with open(output_filename, "w") as f:
                f.write(stdout)
            return output_filename

        for arch in get_archs(lib_path):
            result = process_file(arch)
            if result is not None:
                return result
        return None


class LinuxSymbolDumper:

    def __init__(self):
        self.nm = spawn.find_executable("nm")
        if not self.nm:
            raise SymbolError(
                "Could not find nm, necessary for symbol dumping")

    def store_symbols(self, lib_path, breakpad_id,
                      output_filename_without_extension):
        """
        Returns the filename at which the .sym file was created, or None if no
        symbols were dumped.
        """
        output_filename = output_filename_without_extension + ".nmsym"

        proc = subprocess.Popen([self.nm, "--demangle", lib_path],
                                stdout=subprocess.PIPE,
                                stderr=subprocess.PIPE)
        stdout, stderr = proc.communicate()

        if proc.returncode != 0:
            return

        with open(output_filename, "w") as f:
            f.write(stdout)

            # Append nm -D output to the file. On Linux, most system libraries
            # have no "normal" symbols, but they have "dynamic" symbols, which
            # nm -D shows.
            proc = subprocess.Popen([self.nm, "--demangle", "-D", lib_path],
                                    stdout=subprocess.PIPE,
                                    stderr=subprocess.PIPE)
            stdout, stderr = proc.communicate()
            if proc.returncode == 0:
                f.write(stdout)
        return output_filename


class ProfileSymbolicator:

    def __init__(self, options):
        self.options = options
        self.sym_file_manager = SymFileManager(self.options)
        self.symbol_dumper = self.get_symbol_dumper()

    def get_symbol_dumper(self):
        try:
            if platform.system() == "Darwin":
                return OSXSymbolDumper()
            elif platform.system() == "Linux":
                return LinuxSymbolDumper()
        except SymbolError:
            return None

    def integrate_symbol_zip_from_url(self, symbol_zip_url):
        if platform.system() not in self.options['platformsRequiringSymbols']\
                or self.have_integrated(symbol_zip_url):
            return

        LogMessage("Retrieving symbol zip from {symbol_zip_url}...".format(
            symbol_zip_url=symbol_zip_url))
        try:
            io = urllib2.urlopen(symbol_zip_url, None, 30)
            with zipfile.ZipFile(cStringIO.StringIO(io.read())) as zf:
                self.integrate_symbol_zip(zf)
            self._create_file_if_not_exists(self._marker_file(symbol_zip_url))
        except IOError:
            LogMessage("Symbol zip request failed.")

    def integrate_symbol_zip_from_file(self, filename):
        if self.have_integrated(filename):
            return
        with open(filename, 'rb') as f:
            with zipfile.ZipFile(f) as zf:
                self.integrate_symbol_zip(zf)
        self._create_file_if_not_exists(self._marker_file(filename))

    def _create_file_if_not_exists(self, filename):
        try:
            os.makedirs(os.path.dirname(filename))
        except OSError:
            pass
        try:
            open(filename, 'a').close()
        except IOError:
            pass

    def integrate_symbol_zip(self, symbol_zip_file):
        symbol_zip_file.extractall(self.options["symbolPaths"]["FIREFOX"])

    def _marker_file(self, symbol_zip_url):
        marker_dir = os.path.join(
            self.options["symbolPaths"]["FIREFOX"], ".markers")
        return os.path.join(marker_dir,
                            hashlib.sha1(symbol_zip_url).hexdigest())

    def have_integrated(self, symbol_zip_url):
        return os.path.isfile(self._marker_file(symbol_zip_url))

    def get_unknown_modules_in_profile(self, profile_json):
        if "libs" not in profile_json:
            return []
        shared_libraries = profile_json["libs"]
        memoryMap = []
        for lib in shared_libraries:
            memoryMap.append([lib["debugName"], lib["breakpadId"]])

        rawRequest = {"stacks": [[]], "memoryMap": memoryMap,
                      "version": 4, "symbolSources": ["FIREFOX", "WINDOWS"]}
        request = SymbolicationRequest(self.sym_file_manager, rawRequest)
        if not request.isValidRequest:
            return []
        request.Symbolicate(0)  # This sets request.knownModules

        unknown_modules = []
        for i, lib in enumerate(shared_libraries):
            if not request.knownModules[i]:
                unknown_modules.append(lib)
        return unknown_modules

    def dump_and_integrate_missing_symbols(self, profile_json,
                                           symbol_zip_path):
        if not self.symbol_dumper:
            return

        unknown_modules = self.get_unknown_modules_in_profile(profile_json)
        if not unknown_modules:
            return

        # We integrate the dumped symbols by dumping them directly into our
        # symbol directory.
        output_dir = self.options["symbolPaths"]["FIREFOX"]

        # Additionally, we add all dumped symbol files to the missingsymbols
        # zip file.
        with zipfile.ZipFile(symbol_zip_path, 'a', zipfile.ZIP_DEFLATED) as zf:
            for lib in unknown_modules:
                self.dump_and_integrate_symbols_for_lib(lib, output_dir, zf)

    def dump_and_integrate_symbols_for_lib(self, lib, output_dir, zip):
        name = lib["debugName"]
        expected_name_without_extension = os.path.join(name, lib["breakpadId"], name)
        for extension in [".sym", ".nmsym"]:
            expected_name = expected_name_without_extension + extension
            if expected_name in zip.namelist():
                # No need to dump the symbols again if we already have it in
                # the missingsymbols zip file from a previous run.
                zip.extract(expected_name, output_dir)
                return

        lib_path = lib["path"]
        if not os.path.exists(lib_path):
            return

        output_filename_without_extension = os.path.join(
            output_dir, expected_name_without_extension)
        store_path = os.path.dirname(output_filename_without_extension)
        if not os.path.exists(store_path):
            os.makedirs(store_path)

        # Dump the symbols.
        sym_file = self.symbol_dumper.store_symbols(
            lib_path, lib["breakpadId"], output_filename_without_extension)
        if sym_file:
            rootlen = len(os.path.join(output_dir, '_')) - 1
            output_filename = sym_file[rootlen:]
            if output_filename not in zip.namelist():
                zip.write(sym_file, output_filename)

    def symbolicate_profile(self, profile_json):
        if "libs" not in profile_json:
            return

        shared_libraries = profile_json["libs"]
        addresses = self._find_addresses(profile_json)
        symbols_to_resolve = self._assign_symbols_to_libraries(
            addresses, shared_libraries)
        symbolication_table = self._resolve_symbols(symbols_to_resolve)
        self._substitute_symbols(profile_json, symbolication_table)

        for process in profile_json["processes"]:
            self.symbolicate_profile(process)

    def _find_addresses(self, profile_json):
        addresses = set()
        for thread in profile_json["threads"]:
            if isinstance(thread, basestring):
                continue
            for s in thread["stringTable"]:
                if s[0:2] == "0x":
                    addresses.add(s)
        return addresses

    def _substitute_symbols(self, profile_json, symbolication_table):
        for thread in profile_json["threads"]:
            if isinstance(thread, basestring):
                continue
            for i, s in enumerate(thread["stringTable"]):
                thread["stringTable"][i] = symbolication_table.get(s, s)

    def _get_containing_library(self, address, libs):
        left = 0
        right = len(libs) - 1
        while left <= right:
            mid = (left + right) / 2
            if address >= libs[mid]["end"]:
                left = mid + 1
            elif address < libs[mid]["start"]:
                right = mid - 1
            else:
                return libs[mid]
        return None

    def _assign_symbols_to_libraries(self, addresses, shared_libraries):
        libs_with_symbols = {}
        for address in addresses:
            lib = self._get_containing_library(
                int(address, 0), shared_libraries)
            if not lib:
                continue
            if lib["start"] not in libs_with_symbols:
                libs_with_symbols[lib["start"]] = {
                    "library": lib, "symbols": set()}
            libs_with_symbols[lib["start"]]["symbols"].add(address)
        return libs_with_symbols.values()

    def _resolve_symbols(self, symbols_to_resolve):
        memoryMap = []
        processedStack = []
        all_symbols = []
        for moduleIndex, library_with_symbols in enumerate(symbols_to_resolve):
            lib = library_with_symbols["library"]
            symbols = library_with_symbols["symbols"]
            memoryMap.append([lib["debugName"], lib["breakpadId"]])
            all_symbols += symbols
            for symbol in symbols:
                processedStack.append(
                    [moduleIndex, int(symbol, 0) - lib["start"]])

        rawRequest = {"stacks": [processedStack], "memoryMap": memoryMap,
                      "version": 4, "symbolSources": ["FIREFOX", "WINDOWS"]}
        request = SymbolicationRequest(self.sym_file_manager, rawRequest)
        if not request.isValidRequest:
            return {}
        symbolicated_stack = request.Symbolicate(0)
        return dict(zip(all_symbols, symbolicated_stack))
