import ast
import os.path
import sys
from collections import defaultdict
from typing import Optional

import astunparse
import tqdm
from frozendict import frozendict

from operators import evaluate_condition

ROOT_DIR: str = os.path.dirname(__file__)
IN_DIR: str = os.path.join(ROOT_DIR, 'benchmark')
OUT_DIR: str = os.path.join(ROOT_DIR, 'instrumented')
SUFFIX: str = "_instrumented"


class BranchTransformer(ast.NodeTransformer):
    branches_range: dict[str, tuple[int, int]]
    branch_num: int
    instrumented_name: Optional[str]
    in_assert: bool
    in_return: bool

    def __init__(self):
        self.branch_num = 0
        self.instrumented_name = None
        self.in_assert = False
        self.in_return = False
        self.branches_range = {}

    @staticmethod
    def to_instrumented_name(name: str):
        return name + SUFFIX

    @staticmethod
    def to_original_name(name: str):
        assert name.endswith(SUFFIX)
        return name[:len(name) - len(SUFFIX)]

    def visit_Assert(self, ast_node):
        self.in_assert = True
        self.generic_visit(ast_node)
        self.in_assert = False
        return ast_node

    def visit_Return(self, ast_node):
        self.in_return = True
        self.generic_visit(ast_node)
        self.in_return = False
        return ast_node

    def visit_FunctionDef(self, ast_node):
        self.instrumented_name = ast_node.name
        b_start = self.branch_num
        ast_node.name = BranchTransformer.to_instrumented_name(ast_node.name)
        inner_node = self.generic_visit(ast_node)
        self.branches_range[ast_node.name] = (b_start + 1, self.branch_num + 1)
        self.instrumented_name = None
        return inner_node

    def visit_Call(self, ast_node):
        if isinstance(ast_node.func, ast.Name) and ast_node.func.id == self.instrumented_name:
            ast_node.func.id = BranchTransformer.to_instrumented_name(ast_node.func.id)
        return ast_node

    def visit_Compare(self, ast_node):
        if ast_node.ops[0] in [ast.Is, ast.IsNot, ast.In, ast.NotIn] or self.in_assert or self.in_return:
            return self.generic_visit(ast_node)

        self.branch_num += 1
        return ast.Call(func=ast.Name(evaluate_condition.__name__, ast.Load()),
                        args=[ast.Num(self.branch_num),
                              ast.Str(ast_node.ops[0].__class__.__name__),
                              ast_node.left,
                              ast_node.comparators[0]],
                        keywords=[],
                        starargs=None,
                        kwargs=None)


ArgType = str
Arg = tuple[str, ArgType]
Params = frozendict[str, any]
SignatureDict = dict[str, list[Arg]]

n_of_branches: dict[str, tuple[int, int]] = {}
functions: SignatureDict = {}
module_of: dict[str, list[str]] = {}


def instrument(source_path: str, target_path: str, save_instrumented=True):
    global functions, n_of_branches

    with open(source_path, "r") as f:
        source = f.read()

    node = ast.parse(source)
    # print(ast.dump(node, indent=2))
    b = BranchTransformer()
    b.visit(node)

    for f_name, limits in b.branches_range.items():
        n_of_branches[f_name] = limits

    node = ast.fix_missing_locations(node)  # Make sure the line numbers are ok before printing

    if save_instrumented:
        with open(target_path, "w") as f:
            print(astunparse.unparse(node), file=f)

    current_module = sys.modules[__name__]
    code = compile(node, filename="<ast>", mode="exec")
    exec(code, current_module.__dict__)

    # Figure out the top level function definitions
    assert isinstance(node, ast.Module)
    top_level_f_ast: list[ast.FunctionDef] = [f for f in node.body if isinstance(f, ast.FunctionDef)]

    for f in top_level_f_ast:
        if f.name in functions:
            raise ValueError(f"Function '{f.name}' already loaded from another file")

        arg_types: list[Arg] = []

        for arg in f.args.args:
            # fetch annotation type if found else fetch none
            # noinspection PyUnresolvedReferences
            arg_type = None if arg.annotation is None else arg.annotation.id

            arg_types.append((arg.arg, arg_type))

        functions[f.name] = arg_types
        module_of[f.name] = os.path.splitext(os.path.normpath(os.path.relpath(source_path, ROOT_DIR)))[0].split("/")


def invoke(f_name: str, f_args: Params) -> any:
    global functions

    current_module = sys.modules[__name__]

    if f_name not in functions:
        raise ValueError(f"Function '{f_name}' not loaded")

    f_args_signature = functions[f_name]
    for arg_name, arg_type in f_args_signature:
        if arg_name not in f_args:
            raise ValueError(f"Required argument '{arg_name}' not provided")

    return getattr(current_module, f_name)(**f_args)


def find_py_files(search_dir: str):
    for (cwd, dirs, files) in os.walk(search_dir):
        for file in files:
            if file.endswith(".py"):
                yield os.path.join(cwd, file)


def load_benchmark(save_instrumented=True, files: list[str] = ()):
    to_load = set([os.path.splitext(os.path.basename(file))[0] + ".py" for file in files])
    do_all = len(to_load) == 0

    for file in tqdm.tqdm(find_py_files(IN_DIR), desc="Instrumenting"):
        filename = os.path.basename(file)
        if do_all or filename in to_load:
            instrument(file, os.path.join(OUT_DIR, filename), save_instrumented=save_instrumented)


def call_statement(f_name: str, f_args: Params) -> str:
    arg_list: list[str] = []
    for k, v in f_args.items():
        arg_list.append(f"{k}={repr(v)}")  # quote strings

    return f"{f_name}({', '.join(arg_list)})"


def get_benchmark() -> dict[str, list[str]]:
    """
    Returns a dictionary associated each source code file name loaded (without extension) with the list of
    (non-instrumented) function names defined within it
    """

    names: defaultdict[str, list[str]] = defaultdict(list)

    for f in functions:
        names[module_of[f][-1]].append(BranchTransformer.to_original_name(f))

    return dict(names)


if __name__ == '__main__':
    load_benchmark(save_instrumented=True)