import ast
import re

from ate.utils import long_type
from ate.exception import ParamsError

variable_regexp = r"\$([\w_]+)"
function_regexp = r"\$\{[\w_]+\([\$\w_ =,]*\)\}"
function_regexp_compile = re.compile(r"^\$\{([\w_]+)\(([\$\w_ =,]*)\)\}$")


def extract_variables(content):
    """ extract all variable names from content, which is in format $variable
    @param (str) content
    @return (list) variable name list

    e.g. $variable => ["variable"]
         /blog/$postid => ["postid"]
         /$var1/$var2 => ["var1", "var2"]
         abc => []
    """
    try:
        return re.findall(variable_regexp, content)
    except TypeError:
        return []

def extract_functions(content):
    """ extract all functions from string content, which are in format ${fun()}
    @param (str) content
    @return (list) functions list

    e.g. ${func(5)} => ["${func(5)}"]
         ${func(a=1, b=2)} => ["${func(a=1, b=2)}"]
         /api/1000?_t=${get_timestamp()} => ["get_timestamp()"]
         /api/${add(1, 2)} => ["add(1, 2)"]
         "/api/${add(1, 2)}?_t=${get_timestamp()}" => ["${add(1, 2)}", "${get_timestamp()}"]
    """
    try:
        return re.findall(function_regexp, content)
    except TypeError:
        return []

def parse_string_value(str_value):
    """ parse string to number if possible
    e.g. "123" => 123
         "12.2" => 12.3
         "abc" => "abc"
         "$var" => "$var"
    """
    try:
        return ast.literal_eval(str_value)
    except ValueError:
        return str_value
    except SyntaxError:
        # e.g. $var, ${func}
        return str_value

def parse_function(content):
    """ parse function name and args from string content.
    @param (str) content
    @return (dict) function name and args

    e.g. ${func()} => {'func_name': 'func', 'args': [], 'kwargs': {}}
         ${func(5)} => {'func_name': 'func', 'args': [5], 'kwargs': {}}
         ${func(1, 2)} => {'func_name': 'func', 'args': [1, 2], 'kwargs': {}}
         ${func(a=1, b=2)} => {'func_name': 'func', 'args': [], 'kwargs': {'a': 1, 'b': 2}}
         ${func(1, 2, a=3, b=4)} => {'func_name': 'func', 'args': [1, 2], 'kwargs': {'a':3, 'b':4}}
    """
    function_meta = {
        "args": [],
        "kwargs": {}
    }
    matched = function_regexp_compile.match(content)
    function_meta["func_name"] = matched.group(1)

    args_str = matched.group(2).replace(" ", "")
    if args_str == "":
        return function_meta

    args_list = args_str.split(',')
    for arg in args_list:
        if '=' in arg:
            key, value = arg.split('=')
            function_meta["kwargs"][key] = parse_string_value(value)
        else:
            function_meta["args"].append(parse_string_value(arg))

    return function_meta

def eval_content_variables(content, variable_mapping):
    """ replace all variables of string content with mapping value.
    @param (str) content
    @return (str) parsed content

    e.g.
        variable_mapping = {
            "var_1": "abc",
            "var_2": "def"
        }
        $var_1 => "abc"
        $var_1#XYZ => "abc#XYZ"
        /$var_1/$var_2/var3 => "/abc/def/var3"
        ${func($var_1, $var_2, xyz)} => "${func(abc, def, xyz)}"
    """
    variables_list = extract_variables(content)
    for variable_name in variables_list:
        if variable_name not in variable_mapping:
            raise ParamsError(
                "%s is not defined in bind variables!" % variable_name)

        variable_value = variable_mapping.get(variable_name)
        if "${}".format(variable_name) == content:
            # content is a variable
            content = variable_value
        else:
            # content contains one or many variables
            content = content.replace(
                "${}".format(variable_name),
                str(variable_value), 1
            )

    return content


class TestcaseParser(object):

    def __init__(self, variables_binds={}, functions_binds={}):
        self.bind_variables(variables_binds)
        self.bind_functions(functions_binds)

    def bind_variables(self, variables_binds):
        """ bind variables to current testcase parser
        @param (dict) variables_binds, variables binds mapping
            {
                "authorization": "a83de0ff8d2e896dbd8efb81ba14e17d",
                "random": "A2dEx",
                "data": {"name": "user", "password": "123456"},
                "uuid": 1000
            }
        """
        self.variables_binds = variables_binds

    def bind_functions(self, functions_binds):
        """ bind functions to current testcase parser
        @param (dict) functions_binds, functions binds mapping
            {
                "add_two_nums": lambda a, b=1: a + b
            }
        """
        self.functions_binds = functions_binds

    def eval_content_functions(self, content):
        functions_list = extract_functions(content)
        for func_content in functions_list:
            function_meta = parse_function(func_content)
            func_name = function_meta['func_name']

            func = self.functions_binds.get(func_name)
            if func is None:
                raise ParamsError(
                    "%s is not defined in bind functions!" % func_name)

            args = function_meta.get('args', [])
            kwargs = function_meta.get('kwargs', {})
            args = self.parse_content_with_bindings(args)
            kwargs = self.parse_content_with_bindings(kwargs)
            eval_value = func(*args, **kwargs)

            if func_content == content:
                # content is a variable
                content = eval_value
            else:
                # content contains one or many variables
                content = content.replace(
                    func_content,
                    str(eval_value), 1
                )

        return content

    def parse_content_with_bindings(self, content):
        """ parse content recursively, each variable and function in content will be evaluated.

        @param (dict) content in any data structure
            {
                "url": "http://127.0.0.1:5000/api/users/$uid/${add_two_nums(1, 1)}",
                "method": "POST",
                "headers": {
                    "Content-Type": "application/json",
                    "authorization": "$authorization",
                    "random": "$random",
                    "sum": "${add_two_nums(1, 2)}"
                },
                "body": "$data"
            }
        @return (dict) parsed content with evaluated bind values
            {
                "url": "http://127.0.0.1:5000/api/users/1000/2",
                "method": "POST",
                "headers": {
                    "Content-Type": "application/json",
                    "authorization": "a83de0ff8d2e896dbd8efb81ba14e17d",
                    "random": "A2dEx",
                    "sum": 3
                },
                "body": {"name": "user", "password": "123456"}
            }
        """

        if isinstance(content, (list, tuple)):
            return [
                self.parse_content_with_bindings(item)
                for item in content
            ]

        if isinstance(content, dict):
            evaluated_data = {}
            for key, value in content.items():
                eval_key = self.parse_content_with_bindings(key)
                eval_value = self.parse_content_with_bindings(value)
                evaluated_data[eval_key] = eval_value

            return evaluated_data

        if isinstance(content, (int, long_type, float, complex)):
            return content

        # content is in string format here
        content = "" if content is None else content.strip()

        # replace functions with evaluated value
        # Notice: eval_content_functions must be called before eval_content_variables
        content = self.eval_content_functions(content)

        # replace variables with binding value
        content = eval_content_variables(content, self.variables_binds)

        return content