from pathlib import Path

from parsimonious import NodeVisitor  # type: ignore

from .scanner import scan
from .parser import parse_header


class DeclarationVisitor(NodeVisitor):
    def __init__(self, include_folders):
        self.data = []
        self.include_folders = include_folders

    def visit_HeaderFile(self, node, visited_children):
        includes, elements = visited_children
        return elements

    def visit_ImplementationFile(self, node, visited_children):
        return [x for x in visited_children if x is not None]

    def visit_IncludeStatement(self, node, visited_children):
        include, included_header, semicolon = visited_children
        assert include.text[0].type == 'include'
        assert included_header.type == 'string_literal'
        included_header = included_header.data
        assert semicolon.text[0].type == ';'
        for include_folder in self.include_folders:
            header = Path(include_folder) / included_header
            if header.exists():
                with open(header, 'r', encoding='utf-8') as header_file:
                    header_text = header_file.read()
                header_parse_tree = parse_header(scan(header_text))
                return self.visit(header_parse_tree)
        raise FileNotFoundError(included_header)

    def visit_NormalStructDefinition(self, node, visited_children):
        struct, name, lbrace, fields, rbrace = visited_children
        assert struct.text[0].type == 'struct'
        assert lbrace.text[0].type == '{'
        assert rbrace.text[0].type == '}'
        name = name.data
        return f"struct {name}"

    def visit_OpaqueStructDefinition(self, node, visited_children):
        opaque, struct, name, semi = visited_children
        assert opaque.text[0].type == 'opaque'
        assert struct.text[0].type == 'struct'
        assert semi.text[0].type == ';'
        name = name.data
        return f"struct {name}"

    def visit_EnumDefinition(self, node, visited_children):
        enum, name, lbrace, first_member, extra_members, trailing_comma, rbrace = visited_children
        assert enum.text[0].type == 'enum'
        assert lbrace.text[0].type == '{'
        assert rbrace.text[0].type == '}'
        name = name.data
        return f"enum {name}"

    def visit_RobustUnionDefinition(self, node, visited_children):
        union, name, lbrace, tag, body, rbrace = visited_children
        assert union.text[0].type == 'union'
        assert lbrace.text[0].type == '{'
        assert rbrace.text[0].type == '}'
        name = name.data
        return f"union {name}"

    def visit_FragileUnionDefinition(self, node, visited_children):
        fragile, union, name, lbrace, body, rbrace = visited_children
        assert fragile.text[0].type == 'fragile'
        assert union.text[0].type == 'union'
        assert lbrace.text[0].type == '{'
        assert rbrace.text[0].type == '}'
        name = name.data
        return f"union {name}"

    def visit_FunctionDeclaration(self, node, visited_children):
        signature, semi = visited_children
        assert semi.text[0].type == ';'
        return signature

    def visit_VariableDefinition(self, node, visited_children):
        type, name, eq, value, semi = visited_children
        assert eq.text[0].type == '='
        assert semi.text[0].type == ';'
        name = name.data
        return name

    def visit_VariableDeclaration(self, node, visited_children):
        type, name, semi = visited_children
        assert semi.text[0].type == ';'
        name = name.data
        return name

    def visit_FunctionDefinition(self, node, visited_children):
        signature, body = visited_children
        return signature

    def visit_FunctionSignature(self, node, visited_children):
        return_type, name, lparen, args, rparen = visited_children
        assert name.type == 'identifier'
        name = name.data
        assert lparen.text[0].type == '('
        assert rparen.text[0].type == ')'
        return return_type, name, args

    def visit_constant(self, node, visited_children):
        return node.text[0]

    def visit_string_literal(self, node, visited_children):
        return node.text[0]

    def visit_identifier(self, node, visited_children):
        return node.text[0]

    def generic_visit(self, node, visited_children):
        """ The generic visit method. """
        if not visited_children:
            return node
        if len(visited_children) == 1:
            return visited_children[0]
        return visited_children


def load_declarations(parse_tree):
    declarations = DeclarationVisitor([])
    return declarations.visit(parse_tree)