import os
import json
import shutil
import subprocess
from build import *
from pathlib import Path as SysPath
from cache import Cache
from env import Environment
from platform import Platform
from target import Target
from path import Path

class GenericBuildSystem(BuildSystem):
    def __init__(self, **kwargs):
        self.__data = kwargs.get('data', None)
        super().__init__(**kwargs)


    def __get_watched_files(self):
        result = []
        ns = self.get_path_namespaces()

        if 'watch_files' in self.__data:
            watch_list = self.__data['watch_files']
            for p in watch_list:
                path = Path(p)

                real_paths = path.expand_path(relative_to=ns)
                for p2 in real_paths:
                    result.append(p2)

        manifest_path = os.path.join(self.binary_dir(), 'compile_commands.json')
        manifest_file = None
        manifest = None
        try:
            manifest_file = open(manifest_path, mode='r')
        except:
            return result

        try:
            manifest = json.load(manifest_file)
        except:
            return result

        for v in manifest:
            if 'file' not in v:
                continue

            path = v['file']
            result.append(path)

        return result


    def __get_mtime(self):
        files = self.__get_watched_files()
        result = 0

        for path in files:
            mtime = os.path.getmtime(path)

            if mtime > result:
                result = mtime

        return result


    def _is_configuration_out_of_date(self):
        return False


    def _is_build_out_of_date(self):
        current_mtime = self.__get_mtime()
        target_mtime = Cache.get(f'component.{self.name()}.build-mtime')
        if target_mtime is None:
            return True

        if current_mtime > target_mtime:
            return True

        for d in self.parent().collect_dependencies():
            build_system = d.build_system()
            if build_system is None:
                continue

            if build_system.is_build_out_of_date() or build_system.is_configuration_out_of_date():
                return True

        return False


    def __run_command(self, name, **kwargs):
        verbose = kwargs.get('verbose', False)
        ns = self.get_path_namespaces()
        stdout = None
        if not verbose:
            stdout = subprocess.DEVNULL

        cmd = self.__data.get(name, None)
        if cmd is None:
            return

        args = cmd.get('args', None)
        if args is None:
            raise BuildConfigurationError(f'{self.name()} is incorrectly configured. build_command has no args defined')


        expanded_args = []
        for p in args:
            parts = p.split(':')
            if len(parts) < 2 or parts[0] not in ns:
                expanded_args.append(p)
                continue

            paths = Path(p).expand_path(relative_to=ns)
            expanded_args.extend(paths)

        result = subprocess.run(expanded_args, stdout=stdout)
        if result.returncode != 0:
            raise BuildConfigurationError(f'Execution of {name} for {self.name()} failed. See log for details')


    def configure(self, **kwargs):
        self.__run_command('configure_command', **kwargs)


    def build(self, **kwargs):
        self.__run_command('build_command', **kwargs)


    def install(self, **kwargs):
        self.install_from_seed()

        previous_mtime = Cache.get(f'component.{self.name()}.build-mtime')
        if previous_mtime is None:
            previous_mtime = 0

        new_mtime = self.__get_mtime()
        if new_mtime > previous_mtime:
            Cache.set(f'component.{self.name()}.build-mtime', new_mtime)