#!/usr/bin/env python3
# Copyright 2016 The Meson development team

# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at

#     http://www.apache.org/licenses/LICENSE-2.0

# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.

# This class contains the basic functionality needed to run any interpreter
# or an interpreter-based tool.

# This tool is used to manipulate an existing Meson build definition.
#
# - add a file to a target
# - remove files from a target
# - move targets
# - reindent?
from __future__ import annotations

from .ast import IntrospectionInterpreter, BUILD_TARGET_FUNCTIONS, AstConditionLevel, AstIDGenerator, AstIndentationGenerator, AstPrinter
from mesonbuild.mesonlib import MesonException
from . import mlog, environment
from functools import wraps
from .mparser import Token, ArrayNode, ArgumentNode, AssignmentNode, BooleanNode, ElementaryNode, IdNode, FunctionNode, StringNode
import json, os, re, sys
import typing as T

if T.TYPE_CHECKING:
    from .mparser import BaseNode

class RewriterException(MesonException):
    pass

def add_arguments(parser, formatter=None):
    parser.add_argument('-s', '--sourcedir', type=str, default='.', metavar='SRCDIR', help='Path to source directory.')
    parser.add_argument('-V', '--verbose', action='store_true', default=False, help='Enable verbose output')
    parser.add_argument('-S', '--skip-errors', dest='skip', action='store_true', default=False, help='Skip errors instead of aborting')
    subparsers = parser.add_subparsers(dest='type', title='Rewriter commands', description='Rewrite command to execute')

    # Target
    tgt_parser = subparsers.add_parser('target', help='Modify a target', formatter_class=formatter)
    tgt_parser.add_argument('-s', '--subdir', default='', dest='subdir', help='Subdirectory of the new target (only for the "add_target" action)')
    tgt_parser.add_argument('--type', dest='tgt_type', choices=rewriter_keys['target']['target_type'][2], default='executable',
                            help='Type of the target to add (only for the "add_target" action)')
    tgt_parser.add_argument('target', help='Name or ID of the target')
    tgt_parser.add_argument('operation', choices=['add', 'rm', 'add_target', 'rm_target', 'add_extra_files', 'rm_extra_files', 'info'],
                            help='Action to execute')
    tgt_parser.add_argument('sources', nargs='*', help='Sources to add/remove')

    # KWARGS
    kw_parser = subparsers.add_parser('kwargs', help='Modify keyword arguments', formatter_class=formatter)
    kw_parser.add_argument('operation', choices=rewriter_keys['kwargs']['operation'][2],
                           help='Action to execute')
    kw_parser.add_argument('function', choices=list(rewriter_func_kwargs.keys()),
                           help='Function type to modify')
    kw_parser.add_argument('id', help='ID of the function to modify (can be anything for "project")')
    kw_parser.add_argument('kwargs', nargs='*', help='Pairs of keyword and value')

    # Default options
    def_parser = subparsers.add_parser('default-options', help='Modify the project default options', formatter_class=formatter)
    def_parser.add_argument('operation', choices=rewriter_keys['default_options']['operation'][2],
                            help='Action to execute')
    def_parser.add_argument('options', nargs='*', help='Key, value pairs of configuration option')

    # JSON file/command
    cmd_parser = subparsers.add_parser('command', help='Execute a JSON array of commands', formatter_class=formatter)
    cmd_parser.add_argument('json', help='JSON string or file to execute')

class RequiredKeys:
    def __init__(self, keys):
        self.keys = keys

    def __call__(self, f):
        @wraps(f)
        def wrapped(*wrapped_args, **wrapped_kwargs):
            assert len(wrapped_args) >= 2
            cmd = wrapped_args[1]
            for key, val in self.keys.items():
                typ = val[0] # The type of the value
                default = val[1] # The default value -- None is required
                choices = val[2] # Valid choices -- None is for everything
                if key not in cmd:
                    if default is not None:
                        cmd[key] = default
                    else:
                        raise RewriterException('Key "{}" is missing in object for {}'
                                                .format(key, f.__name__))
                if not isinstance(cmd[key], typ):
                    raise RewriterException('Invalid type of "{}". Required is {} but provided was {}'
                                            .format(key, typ.__name__, type(cmd[key]).__name__))
                if choices is not None:
                    assert isinstance(choices, list)
                    if cmd[key] not in choices:
                        raise RewriterException('Invalid value of "{}": Possible values are {} but provided was "{}"'
                                                .format(key, choices, cmd[key]))
            return f(*wrapped_args, **wrapped_kwargs)

        return wrapped

class MTypeBase:
    def __init__(self, node: T.Optional[BaseNode] = None):
        if node is None:
            self.node = self._new_node()  # lgtm [py/init-calls-subclass] (node creation does not depend on base class state)
        else:
            self.node = node
        self.node_type = None
        for i in self.supported_nodes():  # lgtm [py/init-calls-subclass] (listing nodes does not depend on base class state)
            if isinstance(self.node, i):
                self.node_type = i

    def _new_node(self):
        # Overwrite in derived class
        raise RewriterException('Internal error: _new_node of MTypeBase was called')

    def can_modify(self):
        return self.node_type is not None

    def get_node(self):
        return self.node

    def supported_nodes(self):
        # Overwrite in derived class
        return []

    def set_value(self, value):
        # Overwrite in derived class
        mlog.warning('Cannot set the value of type', mlog.bold(type(self).__name__), '--> skipping')

    def add_value(self, value):
        # Overwrite in derived class
        mlog.warning('Cannot add a value of type', mlog.bold(type(self).__name__), '--> skipping')

    def remove_value(self, value):
        # Overwrite in derived class
        mlog.warning('Cannot remove a value of type', mlog.bold(type(self).__name__), '--> skipping')

    def remove_regex(self, value):
        # Overwrite in derived class
        mlog.warning('Cannot remove a regex in type', mlog.bold(type(self).__name__), '--> skipping')

class MTypeStr(MTypeBase):
    def __init__(self, node: T.Optional[BaseNode] = None):
        super().__init__(node)

    def _new_node(self):
        return StringNode(Token('', '', 0, 0, 0, None, ''))

    def supported_nodes(self):
        return [StringNode]

    def set_value(self, value):
        self.node.value = str(value)

class MTypeBool(MTypeBase):
    def __init__(self, node: T.Optional[BaseNode] = None):
        super().__init__(node)

    def _new_node(self):
        return BooleanNode(Token('', '', 0, 0, 0, None, False))

    def supported_nodes(self):
        return [BooleanNode]

    def set_value(self, value):
        self.node.value = bool(value)

class MTypeID(MTypeBase):
    def __init__(self, node: T.Optional[BaseNode] = None):
        super().__init__(node)

    def _new_node(self):
        return IdNode(Token('', '', 0, 0, 0, None, ''))

    def supported_nodes(self):
        return [IdNode]

    def set_value(self, value):
        self.node.value = str(value)

class MTypeList(MTypeBase):
    def __init__(self, node: T.Optional[BaseNode] = None):
        super().__init__(node)

    def _new_node(self):
        return ArrayNode(ArgumentNode(Token('', '', 0, 0, 0, None, '')), 0, 0, 0, 0)

    def _new_element_node(self, value):
        # Overwrite in derived class
        raise RewriterException('Internal error: _new_element_node of MTypeList was called')

    def _ensure_array_node(self):
        if not isinstance(self.node, ArrayNode):
            tmp = self.node
            self.node = self._new_node()
            self.node.args.arguments += [tmp]

    def _check_is_equal(self, node, value) -> bool:
        # Overwrite in derived class
        return False

    def _check_regex_matches(self, node, regex: str) -> bool:
        # Overwrite in derived class
        return False

    def get_node(self):
        if isinstance(self.node, ArrayNode):
            if len(self.node.args.arguments) == 1:
                return self.node.args.arguments[0]
        return self.node

    def supported_element_nodes(self):
        # Overwrite in derived class
        return []

    def supported_nodes(self):
        return [ArrayNode] + self.supported_element_nodes()

    def set_value(self, value):
        if not isinstance(value, list):
            value = [value]
        self._ensure_array_node()
        self.node.args.arguments = [] # Remove all current nodes
        for i in value:
            self.node.args.arguments += [self._new_element_node(i)]

    def add_value(self, value):
        if not isinstance(value, list):
            value = [value]
        self._ensure_array_node()
        for i in value:
            self.node.args.arguments += [self._new_element_node(i)]

    def _remove_helper(self, value, equal_func):
        def check_remove_node(node):
            for j in value:
                if equal_func(i, j):
                    return True
            return False

        if not isinstance(value, list):
            value = [value]
        self._ensure_array_node()
        removed_list = []
        for i in self.node.args.arguments:
            if not check_remove_node(i):
                removed_list += [i]
        self.node.args.arguments = removed_list

    def remove_value(self, value):
        self._remove_helper(value, self._check_is_equal)

    def remove_regex(self, regex: str):
        self._remove_helper(regex, self._check_regex_matches)

class MTypeStrList(MTypeList):
    def __init__(self, node: T.Optional[BaseNode] = None):
        super().__init__(node)

    def _new_element_node(self, value):
        return StringNode(Token('', '', 0, 0, 0, None, str(value)))

    def _check_is_equal(self, node, value) -> bool:
        if isinstance(node, StringNode):
            return node.value == value
        return False

    def _check_regex_matches(self, node, regex: str) -> bool:
        if isinstance(node, StringNode):
            return re.match(regex, node.value) is not None
        return False

    def supported_element_nodes(self):
        return [StringNode]

class MTypeIDList(MTypeList):
    def __init__(self, node: T.Optional[BaseNode] = None):
        super().__init__(node)

    def _new_element_node(self, value):
        return IdNode(Token('', '', 0, 0, 0, None, str(value)))

    def _check_is_equal(self, node, value) -> bool:
        if isinstance(node, IdNode):
            return node.value == value
        return False

    def _check_regex_matches(self, node, regex: str) -> bool:
        if isinstance(node, StringNode):
            return re.match(regex, node.value) is not None
        return False

    def supported_element_nodes(self):
        return [IdNode]

rewriter_keys = {
    'default_options': {
        'operation': (str, None, ['set', 'delete']),
        'options': (dict, {}, None)
    },
    'kwargs': {
        'function': (str, None, None),
        'id': (str, None, None),
        'operation': (str, None, ['set', 'delete', 'add', 'remove', 'remove_regex', 'info']),
        'kwargs': (dict, {}, None)
    },
    'target': {
        'target': (str, None, None),
        'operation': (str, None, ['src_add', 'src_rm', 'target_rm', 'target_add', 'extra_files_add', 'extra_files_rm', 'info']),
        'sources': (list, [], None),
        'subdir': (str, '', None),
        'target_type': (str, 'executable', ['both_libraries', 'executable', 'jar', 'library', 'shared_library', 'shared_module', 'static_library']),
    }
}

rewriter_func_kwargs = {
    'dependency': {
        'language': MTypeStr,
        'method': MTypeStr,
        'native': MTypeBool,
        'not_found_message': MTypeStr,
        'required': MTypeBool,
        'static': MTypeBool,
        'version': MTypeStrList,
        'modules': MTypeStrList
    },
    'target': {
        'build_by_default': MTypeBool,
        'build_rpath': MTypeStr,
        'dependencies': MTypeIDList,
        'gui_app': MTypeBool,
        'link_with': MTypeIDList,
        'export_dynamic': MTypeBool,
        'implib': MTypeBool,
        'install': MTypeBool,
        'install_dir': MTypeStr,
        'install_rpath': MTypeStr,
        'pie': MTypeBool
    },
    'project': {
        'default_options': MTypeStrList,
        'meson_version': MTypeStr,
        'license': MTypeStrList,
        'subproject_dir': MTypeStr,
        'version': MTypeStr
    }
}

class Rewriter:
    def __init__(self, sourcedir: str, generator: str = 'ninja', skip_errors: bool = False):
        self.sourcedir = sourcedir
        self.interpreter = IntrospectionInterpreter(sourcedir, '', generator, visitors = [AstIDGenerator(), AstIndentationGenerator(), AstConditionLevel()])
        self.skip_errors = skip_errors
        self.modified_nodes = []
        self.to_remove_nodes = []
        self.to_add_nodes = []
        self.functions = {
            'default_options': self.process_default_options,
            'kwargs': self.process_kwargs,
            'target': self.process_target,
        }
        self.info_dump = None

    def analyze_meson(self):
        mlog.log('Analyzing meson file:', mlog.bold(os.path.join(self.sourcedir, environment.build_filename)))
        self.interpreter.analyze()
        mlog.log('  -- Project:', mlog.bold(self.interpreter.project_data['descriptive_name']))
        mlog.log('  -- Version:', mlog.cyan(self.interpreter.project_data['version']))

    def add_info(self, cmd_type: str, cmd_id: str, data: dict):
        if self.info_dump is None:
            self.info_dump = {}
        if cmd_type not in self.info_dump:
            self.info_dump[cmd_type] = {}
        self.info_dump[cmd_type][cmd_id] = data

    def print_info(self):
        if self.info_dump is None:
            return
        sys.stderr.write(json.dumps(self.info_dump, indent=2))

    def on_error(self):
        if self.skip_errors:
            return mlog.cyan('-->'), mlog.yellow('skipping')
        return mlog.cyan('-->'), mlog.red('aborting')

    def handle_error(self):
        if self.skip_errors:
            return None
        raise MesonException('Rewriting the meson.build failed')

    def find_target(self, target: str):
        def check_list(name: str) -> T.List[BaseNode]:
            result = []
            for i in self.interpreter.targets:
                if name == i['name'] or name == i['id']:
                    result += [i]
            return result

        targets = check_list(target)
        if targets:
            if len(targets) == 1:
                return targets[0]
            else:
                mlog.error('There are multiple targets matching', mlog.bold(target))
                for i in targets:
                    mlog.error('  -- Target name', mlog.bold(i['name']), 'with ID', mlog.bold(i['id']))
                mlog.error('Please try again with the unique ID of the target', *self.on_error())
                self.handle_error()
                return None

        # Check the assignments
        tgt = None
        if target in self.interpreter.assignments:
            node = self.interpreter.assignments[target]
            if isinstance(node, FunctionNode):
                if node.func_name in ['executable', 'jar', 'library', 'shared_library', 'shared_module', 'static_library', 'both_libraries']:
                    tgt = self.interpreter.assign_vals[target]

        return tgt

    def find_dependency(self, dependency: str):
        def check_list(name: str):
            for i in self.interpreter.dependencies:
                if name == i['name']:
                    return i
            return None

        dep = check_list(dependency)
        if dep is not None:
            return dep

        # Check the assignments
        if dependency in self.interpreter.assignments:
            node = self.interpreter.assignments[dependency]
            if isinstance(node, FunctionNode):
                if node.func_name in ['dependency']:
                    name = self.interpreter.flatten_args(node.args)[0]
                    dep = check_list(name)

        return dep

    @RequiredKeys(rewriter_keys['default_options'])
    def process_default_options(self, cmd):
        # First, remove the old values
        kwargs_cmd = {
            'function': 'project',
            'id': "/",
            'operation': 'remove_regex',
            'kwargs': {
                'default_options': [f'{x}=.*' for x in cmd['options'].keys()]
            }
        }
        self.process_kwargs(kwargs_cmd)

        # Then add the new values
        if cmd['operation'] != 'set':
            return

        kwargs_cmd['operation'] = 'add'
        kwargs_cmd['kwargs']['default_options'] = []

        cdata = self.interpreter.coredata
        options = {
            **{str(k): v for k, v in cdata.options.items()},
            **{str(k): v for k, v in cdata.options.items()},
            **{str(k): v for k, v in cdata.options.items()},
            **{str(k): v for k, v in cdata.options.items()},
            **{str(k): v for k, v in cdata.options.items()},
        }

        for key, val in sorted(cmd['options'].items()):
            if key not in options:
                mlog.error('Unknown options', mlog.bold(key), *self.on_error())
                self.handle_error()
                continue

            try:
                val = options[key].validate_value(val)
            except MesonException as e:
                mlog.error('Unable to set', mlog.bold(key), mlog.red(str(e)), *self.on_error())
                self.handle_error()
                continue

            kwargs_cmd['kwargs']['default_options'] += [f'{key}={val}']

        self.process_kwargs(kwargs_cmd)

    @RequiredKeys(rewriter_keys['kwargs'])
    def process_kwargs(self, cmd):
        mlog.log('Processing function type', mlog.bold(cmd['function']), 'with id', mlog.cyan("'" + cmd['id'] + "'"))
        if cmd['function'] not in rewriter_func_kwargs:
            mlog.error('Unknown function type', cmd['function'], *self.on_error())
            return self.handle_error()
        kwargs_def = rewriter_func_kwargs[cmd['function']]

        # Find the function node to modify
        node = None
        arg_node = None
        if cmd['function'] == 'project':
            # msys bash may expand '/' to a path. It will mangle '//' to '/'
            # but in order to keep usage shell-agnostic, also allow `//` as
            # the function ID such that it will work in both msys bash and
            # other shells.
            if {'/', '//'}.isdisjoint({cmd['id']}):
                mlog.error('The ID for the function type project must be "/" or "//" not "' + cmd['id'] + '"', *self.on_error())
                return self.handle_error()
            node = self.interpreter.project_node
            arg_node = node.args
        elif cmd['function'] == 'target':
            tmp = self.find_target(cmd['id'])
            if tmp:
                node = tmp['node']
                arg_node = node.args
        elif cmd['function'] == 'dependency':
            tmp = self.find_dependency(cmd['id'])
            if tmp:
                node = tmp['node']
                arg_node = node.args
        if not node:
            mlog.error('Unable to find the function node')
        assert isinstance(node, FunctionNode)
        assert isinstance(arg_node, ArgumentNode)
        # Transform the key nodes to plain strings
        arg_node.kwargs = {k.value: v for k, v in arg_node.kwargs.items()}

        # Print kwargs info
        if cmd['operation'] == 'info':
            info_data = {}
            for key, val in sorted(arg_node.kwargs.items()):
                info_data[key] = None
                if isinstance(val, ElementaryNode):
                    info_data[key] = val.value
                elif isinstance(val, ArrayNode):
                    data_list = []
                    for i in val.args.arguments:
                        element = None
                        if isinstance(i, ElementaryNode):
                            element = i.value
                        data_list += [element]
                    info_data[key] = data_list

            self.add_info('kwargs', '{}#{}'.format(cmd['function'], cmd['id']), info_data)
            return # Nothing else to do

        # Modify the kwargs
        num_changed = 0
        for key, val in sorted(cmd['kwargs'].items()):
            if key not in kwargs_def:
                mlog.error('Cannot modify unknown kwarg', mlog.bold(key), *self.on_error())
                self.handle_error()
                continue

            # Remove the key from the kwargs
            if cmd['operation'] == 'delete':
                if key in arg_node.kwargs:
                    mlog.log('  -- Deleting', mlog.bold(key), 'from the kwargs')
                    del arg_node.kwargs[key]
                    num_changed += 1
                else:
                    mlog.log('  -- Key', mlog.bold(key), 'is already deleted')
                continue

            if key not in arg_node.kwargs:
                arg_node.kwargs[key] = None
            modifyer = kwargs_def[key](arg_node.kwargs[key])
            if not modifyer.can_modify():
                mlog.log('  -- Skipping', mlog.bold(key), 'because it is to complex to modify')

            # Apply the operation
            val_str = str(val)
            if cmd['operation'] == 'set':
                mlog.log('  -- Setting', mlog.bold(key), 'to', mlog.yellow(val_str))
                modifyer.set_value(val)
            elif cmd['operation'] == 'add':
                mlog.log('  -- Adding', mlog.yellow(val_str), 'to', mlog.bold(key))
                modifyer.add_value(val)
            elif cmd['operation'] == 'remove':
                mlog.log('  -- Removing', mlog.yellow(val_str), 'from', mlog.bold(key))
                modifyer.remove_value(val)
            elif cmd['operation'] == 'remove_regex':
                mlog.log('  -- Removing all values matching', mlog.yellow(val_str), 'from', mlog.bold(key))
                modifyer.remove_regex(val)

            # Write back the result
            arg_node.kwargs[key] = modifyer.get_node()
            num_changed += 1

        # Convert the keys back to IdNode's
        arg_node.kwargs = {IdNode(Token('', '', 0, 0, 0, None, k)): v for k, v in arg_node.kwargs.items()}
        if num_changed > 0 and node not in self.modified_nodes:
            self.modified_nodes += [node]

    def find_assignment_node(self, node: BaseNode) -> AssignmentNode:
        if node.ast_id and node.ast_id in self.interpreter.reverse_assignment:
            return self.interpreter.reverse_assignment[node.ast_id]
        return None

    @RequiredKeys(rewriter_keys['target'])
    def process_target(self, cmd):
        mlog.log('Processing target', mlog.bold(cmd['target']), 'operation', mlog.cyan(cmd['operation']))
        target = self.find_target(cmd['target'])
        if target is None and cmd['operation'] != 'target_add':
            mlog.error('Unknown target', mlog.bold(cmd['target']), *self.on_error())
            return self.handle_error()

        # Make source paths relative to the current subdir
        def rel_source(src: str) -> str:
            subdir = os.path.abspath(os.path.join(self.sourcedir, target['subdir']))
            if os.path.isabs(src):
                return os.path.relpath(src, subdir)
            elif not os.path.exists(src):
                return src # Trust the user when the source doesn't exist
            # Make sure that the path is relative to the subdir
            return os.path.relpath(os.path.abspath(src), subdir)

        if target is not None:
            cmd['sources'] = [rel_source(x) for x in cmd['sources']]

        # Utility function to get a list of the sources from a node
        def arg_list_from_node(n):
            args = []
            if isinstance(n, FunctionNode):
                args = list(n.args.arguments)
                if n.func_name in BUILD_TARGET_FUNCTIONS:
                    args.pop(0)
            elif isinstance(n, ArrayNode):
                args = n.args.arguments
            elif isinstance(n, ArgumentNode):
                args = n.arguments
            return args

        to_sort_nodes = []

        if cmd['operation'] == 'src_add':
            node = None
            if target['sources']:
                node = target['sources'][0]
            else:
                node = target['node']
            assert node is not None

            # Generate the current source list
            src_list = []
            for i in target['sources']:
                for j in arg_list_from_node(i):
                    if isinstance(j, StringNode):
                        src_list += [j.value]

            # Generate the new String nodes
            to_append = []
            for i in sorted(set(cmd['sources'])):
                if i in src_list:
                    mlog.log('  -- Source', mlog.green(i), 'is already defined for the target --> skipping')
                    continue
                mlog.log('  -- Adding source', mlog.green(i), 'at',
                         mlog.yellow(f'{node.filename}:{node.lineno}'))
                token = Token('string', node.filename, 0, 0, 0, None, i)
                to_append += [StringNode(token)]

            # Append to the AST at the right place
            arg_node = None
            if isinstance(node, (FunctionNode, ArrayNode)):
                arg_node = node.args
            elif isinstance(node, ArgumentNode):
                arg_node = node
            assert arg_node is not None
            arg_node.arguments += to_append

            # Mark the node as modified
            if arg_node not in to_sort_nodes and not isinstance(node, FunctionNode):
                to_sort_nodes += [arg_node]
            if node not in self.modified_nodes:
                self.modified_nodes += [node]

        elif cmd['operation'] == 'src_rm':
            # Helper to find the exact string node and its parent
            def find_node(src):
                for i in target['sources']:
                    for j in arg_list_from_node(i):
                        if isinstance(j, StringNode):
                            if j.value == src:
                                return i, j
                return None, None

            for i in cmd['sources']:
                # Try to find the node with the source string
                root, string_node = find_node(i)
                if root is None:
                    mlog.warning('  -- Unable to find source', mlog.green(i), 'in the target')
                    continue

                # Remove the found string node from the argument list
                arg_node = None
                if isinstance(root, (FunctionNode, ArrayNode)):
                    arg_node = root.args
                elif isinstance(root, ArgumentNode):
                    arg_node = root
                assert arg_node is not None
                mlog.log('  -- Removing source', mlog.green(i), 'from',
                         mlog.yellow(f'{string_node.filename}:{string_node.lineno}'))
                arg_node.arguments.remove(string_node)

                # Mark the node as modified
                if arg_node not in to_sort_nodes and not isinstance(root, FunctionNode):
                    to_sort_nodes += [arg_node]
                if root not in self.modified_nodes:
                    self.modified_nodes += [root]

        elif cmd['operation'] == 'extra_files_add':
            tgt_function: FunctionNode = target['node']
            mark_array = True
            try:
                node = target['extra_files'][0]
            except IndexError:
                # Specifying `extra_files` with a list that flattens to empty gives an empty
                # target['extra_files'] list, account for that.
                try:
                    extra_files_key = next(k for k in tgt_function.args.kwargs.keys() if isinstance(k, IdNode) and k.value == 'extra_files')
                    node = tgt_function.args.kwargs[extra_files_key]
                except StopIteration:
                    # Target has no extra_files kwarg, create one
                    node = ArrayNode(ArgumentNode(Token('', tgt_function.filename, 0, 0, 0, None, '[]')), tgt_function.end_lineno, tgt_function.end_colno, tgt_function.end_lineno, tgt_function.end_colno)
                    tgt_function.args.kwargs[IdNode(Token('string', tgt_function.filename, 0, 0, 0, None, 'extra_files'))] = node
                    mark_array = False
                    if tgt_function not in self.modified_nodes:
                        self.modified_nodes += [tgt_function]
                target['extra_files'] = [node]
            if isinstance(node, IdNode):
                node = self.interpreter.assignments[node.value]
                target['extra_files'] = [node]
            if not isinstance(node, ArrayNode):
                mlog.error('Target', mlog.bold(cmd['target']), 'extra_files argument must be a list', *self.on_error())
                return self.handle_error()

            # Generate the current extra files list
            extra_files_list = []
            for i in target['extra_files']:
                for j in arg_list_from_node(i):
                    if isinstance(j, StringNode):
                        extra_files_list += [j.value]

            # Generate the new String nodes
            to_append = []
            for i in sorted(set(cmd['sources'])):
                if i in extra_files_list:
                    mlog.log('  -- Extra file', mlog.green(i), 'is already defined for the target --> skipping')
                    continue
                mlog.log('  -- Adding extra file', mlog.green(i), 'at',
                         mlog.yellow(f'{node.filename}:{node.lineno}'))
                token = Token('string', node.filename, 0, 0, 0, None, i)
                to_append += [StringNode(token)]

            # Append to the AST at the right place
            arg_node = node.args
            arg_node.arguments += to_append

            # Mark the node as modified
            if arg_node not in to_sort_nodes:
                to_sort_nodes += [arg_node]
            # If the extra_files array is newly created, don't mark it as its parent function node already is,
            # otherwise this would cause double modification.
            if mark_array and node not in self.modified_nodes:
                self.modified_nodes += [node]

        elif cmd['operation'] == 'extra_files_rm':
            # Helper to find the exact string node and its parent
            def find_node(src):
                for i in target['extra_files']:
                    for j in arg_list_from_node(i):
                        if isinstance(j, StringNode):
                            if j.value == src:
                                return i, j
                return None, None

            for i in cmd['sources']:
                # Try to find the node with the source string
                root, string_node = find_node(i)
                if root is None:
                    mlog.warning('  -- Unable to find extra file', mlog.green(i), 'in the target')
                    continue

                # Remove the found string node from the argument list
                arg_node = root.args
                mlog.log('  -- Removing extra file', mlog.green(i), 'from',
                         mlog.yellow(f'{string_node.filename}:{string_node.lineno}'))
                arg_node.arguments.remove(string_node)

                # Mark the node as modified
                if arg_node not in to_sort_nodes and not isinstance(root, FunctionNode):
                    to_sort_nodes += [arg_node]
                if root not in self.modified_nodes:
                    self.modified_nodes += [root]

        elif cmd['operation'] == 'target_add':
            if target is not None:
                mlog.error('Can not add target', mlog.bold(cmd['target']), 'because it already exists', *self.on_error())
                return self.handle_error()

            id_base = re.sub(r'[- ]', '_', cmd['target'])
            target_id = id_base + '_exe' if cmd['target_type'] == 'executable' else '_lib'
            source_id = id_base + '_sources'
            filename = os.path.join(cmd['subdir'], environment.build_filename)

            # Build src list
            src_arg_node = ArgumentNode(Token('string', filename, 0, 0, 0, None, ''))
            src_arr_node = ArrayNode(src_arg_node, 0, 0, 0, 0)
            src_far_node = ArgumentNode(Token('string', filename, 0, 0, 0, None, ''))
            src_fun_node = FunctionNode(filename, 0, 0, 0, 0, 'files', src_far_node)
            src_ass_node = AssignmentNode(filename, 0, 0, source_id, src_fun_node)
            src_arg_node.arguments = [StringNode(Token('string', filename, 0, 0, 0, None, x)) for x in cmd['sources']]
            src_far_node.arguments = [src_arr_node]

            # Build target
            tgt_arg_node = ArgumentNode(Token('string', filename, 0, 0, 0, None, ''))
            tgt_fun_node = FunctionNode(filename, 0, 0, 0, 0, cmd['target_type'], tgt_arg_node)
            tgt_ass_node = AssignmentNode(filename, 0, 0, target_id, tgt_fun_node)
            tgt_arg_node.arguments = [
                StringNode(Token('string', filename, 0, 0, 0, None, cmd['target'])),
                IdNode(Token('string', filename, 0, 0, 0, None, source_id))
            ]

            src_ass_node.accept(AstIndentationGenerator())
            tgt_ass_node.accept(AstIndentationGenerator())
            self.to_add_nodes += [src_ass_node, tgt_ass_node]

        elif cmd['operation'] == 'target_rm':
            to_remove = self.find_assignment_node(target['node'])
            if to_remove is None:
                to_remove = target['node']
            self.to_remove_nodes += [to_remove]
            mlog.log('  -- Removing target', mlog.green(cmd['target']), 'at',
                     mlog.yellow(f'{to_remove.filename}:{to_remove.lineno}'))

        elif cmd['operation'] == 'info':
            # T.List all sources in the target
            src_list = []
            for i in target['sources']:
                for j in arg_list_from_node(i):
                    if isinstance(j, StringNode):
                        src_list += [j.value]
            extra_files_list = []
            for i in target['extra_files']:
                for j in arg_list_from_node(i):
                    if isinstance(j, StringNode):
                        extra_files_list += [j.value]
            test_data = {
                'name': target['name'],
                'sources': src_list,
                'extra_files': extra_files_list
            }
            self.add_info('target', target['id'], test_data)

        # Sort files
        for i in to_sort_nodes:
            convert = lambda text: int(text) if text.isdigit() else text.lower()
            alphanum_key = lambda key: [convert(c) for c in re.split('([0-9]+)', key)]
            path_sorter = lambda key: ([(key.count('/') <= idx, alphanum_key(x)) for idx, x in enumerate(key.split('/'))])

            unknown = [x for x in i.arguments if not isinstance(x, StringNode)]
            sources = [x for x in i.arguments if isinstance(x, StringNode)]
            sources = sorted(sources, key=lambda x: path_sorter(x.value))
            i.arguments = unknown + sources

    def process(self, cmd):
        if 'type' not in cmd:
            raise RewriterException('Command has no key "type"')
        if cmd['type'] not in self.functions:
            raise RewriterException('Unknown command "{}". Supported commands are: {}'
                                    .format(cmd['type'], list(self.functions.keys())))
        self.functions[cmd['type']](cmd)

    def apply_changes(self):
        assert all(hasattr(x, 'lineno') and hasattr(x, 'colno') and hasattr(x, 'filename') for x in self.modified_nodes)
        assert all(hasattr(x, 'lineno') and hasattr(x, 'colno') and hasattr(x, 'filename') for x in self.to_remove_nodes)
        assert all(isinstance(x, (ArrayNode, FunctionNode)) for x in self.modified_nodes)
        assert all(isinstance(x, (ArrayNode, AssignmentNode, FunctionNode)) for x in self.to_remove_nodes)
        # Sort based on line and column in reversed order
        work_nodes = [{'node': x, 'action': 'modify'} for x in self.modified_nodes]
        work_nodes += [{'node': x, 'action': 'rm'} for x in self.to_remove_nodes]
        work_nodes = list(sorted(work_nodes, key=lambda x: (x['node'].lineno, x['node'].colno), reverse=True))
        work_nodes += [{'node': x, 'action': 'add'} for x in self.to_add_nodes]

        # Generating the new replacement string
        str_list = []
        for i in work_nodes:
            new_data = ''
            if i['action'] == 'modify' or i['action'] == 'add':
                printer = AstPrinter()
                i['node'].accept(printer)
                printer.post_process()
                new_data = printer.result.strip()
            data = {
                'file': i['node'].filename,
                'str': new_data,
                'node': i['node'],
                'action': i['action']
            }
            str_list += [data]

        # Load build files
        files = {}
        for i in str_list:
            if i['file'] in files:
                continue
            fpath = os.path.realpath(os.path.join(self.sourcedir, i['file']))
            fdata = ''
            # Create an empty file if it does not exist
            if not os.path.exists(fpath):
                with open(fpath, 'w', encoding='utf-8'):
                    pass
            with open(fpath, encoding='utf-8') as fp:
                fdata = fp.read()

            # Generate line offsets numbers
            m_lines = fdata.splitlines(True)
            offset = 0
            line_offsets = []
            for j in m_lines:
                line_offsets += [offset]
                offset += len(j)

            files[i['file']] = {
                'path': fpath,
                'raw': fdata,
                'offsets': line_offsets
            }

        # Replace in source code
        def remove_node(i):
            offsets = files[i['file']]['offsets']
            raw = files[i['file']]['raw']
            node = i['node']
            line = node.lineno - 1
            col = node.colno
            start = offsets[line] + col
            end = start
            if isinstance(node, (ArrayNode, FunctionNode)):
                end = offsets[node.end_lineno - 1] + node.end_colno

            # Only removal is supported for assignments
            elif isinstance(node, AssignmentNode) and i['action'] == 'rm':
                if isinstance(node.value, (ArrayNode, FunctionNode)):
                    remove_node({'file': i['file'], 'str': '', 'node': node.value, 'action': 'rm'})
                    raw = files[i['file']]['raw']
                while raw[end] != '=':
                    end += 1
                end += 1 # Handle the '='
                while raw[end] in [' ', '\n', '\t']:
                    end += 1

            files[i['file']]['raw'] = raw[:start] + i['str'] + raw[end:]

        for i in str_list:
            if i['action'] in ['modify', 'rm']:
                remove_node(i)
            elif i['action'] in ['add']:
                files[i['file']]['raw'] += i['str'] + '\n'

        # Write the files back
        for key, val in files.items():
            mlog.log('Rewriting', mlog.yellow(key))
            with open(val['path'], 'w', encoding='utf-8') as fp:
                fp.write(val['raw'])

target_operation_map = {
    'add': 'src_add',
    'rm': 'src_rm',
    'add_target': 'target_add',
    'rm_target': 'target_rm',
    'add_extra_files': 'extra_files_add',
    'rm_extra_files': 'extra_files_rm',
    'info': 'info',
}

def list_to_dict(in_list: T.List[str]) -> T.Dict[str, str]:
    result = {}
    it = iter(in_list)
    try:
        for i in it:
            # calling next(it) is not a mistake, we're taking the next element from
            # the iterator, avoiding the need to preprocess it into a sequence of
            # key value pairs.
            result[i] = next(it)
    except StopIteration:
        raise TypeError('in_list parameter of list_to_dict must have an even length.')
    return result

def generate_target(options) -> T.List[dict]:
    return [{
        'type': 'target',
        'target': options.target,
        'operation': target_operation_map[options.operation],
        'sources': options.sources,
        'subdir': options.subdir,
        'target_type': options.tgt_type,
    }]

def generate_kwargs(options) -> T.List[dict]:
    return [{
        'type': 'kwargs',
        'function': options.function,
        'id': options.id,
        'operation': options.operation,
        'kwargs': list_to_dict(options.kwargs),
    }]

def generate_def_opts(options) -> T.List[dict]:
    return [{
        'type': 'default_options',
        'operation': options.operation,
        'options': list_to_dict(options.options),
    }]

def generate_cmd(options) -> T.List[dict]:
    if os.path.exists(options.json):
        with open(options.json, encoding='utf-8') as fp:
            return json.load(fp)
    else:
        return json.loads(options.json)

# Map options.type to the actual type name
cli_type_map = {
    'target': generate_target,
    'tgt': generate_target,
    'kwargs': generate_kwargs,
    'default-options': generate_def_opts,
    'def': generate_def_opts,
    'command': generate_cmd,
    'cmd': generate_cmd,
}

def run(options):
    if not options.verbose:
        mlog.set_quiet()

    try:
        rewriter = Rewriter(options.sourcedir, skip_errors=options.skip)
        rewriter.analyze_meson()

        if options.type is None:
            mlog.error('No command specified')
            return 1

        commands = cli_type_map[options.type](options)

        if not isinstance(commands, list):
            raise TypeError('Command is not a list')

        for i in commands:
            if not isinstance(i, object):
                raise TypeError('Command is not an object')
            rewriter.process(i)

        rewriter.apply_changes()
        rewriter.print_info()
        return 0
    except Exception as e:
        raise e
    finally:
        mlog.set_verbose()