from typing import Optional, Any, Callable
from base import Search

type QueryCommand = Callable[[Any, Optional[str]], Search]

class QueryParser():
    def __init__(self, userdata: Any, default_command: str) -> Any:
        self.commands: dict[str, QueryCommand] = {}
        self.escaped_commands: dict[str, str] = {}
        self.userdata: Any = userdata
        self.default_command: str = default_command

    def add_command(self, name: str, search: QueryCommand) -> None:
        self.commands[name] = search
        self.escaped_commands['\\' + name] = name

    def parse_query(self, query: str) -> Search:
        arg = query
        search = self.commands[self.default_command]

        sp = query.split(' ')

        for index, word in enumerate(sp):
            col = word.find(':')
            if col == -1:
                continue
            command = word[0:col]
            if command in self.escaped_commands:
                query = query.replace(command, self.escaped_commands[command], 1)
                continue
            if command in self.commands:
                if col + 1 < len(word):
                    arg = word[col+1:]
                else:
                    arg = None
                search = self.commands[command]
                if index == 0:
                    if len(sp) > 1:
                        query = query.replace(word + ' ', '', 1)
                    else:
                        query = query.replace(word, '', 1)
                else:
                    query = query.replace(' ' + word + ' ', '', 1)

        return search(self.userdata, arg)