#
# Copyright 2021 Espressif Systems (Shanghai) CO LTD
#
# 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.
#

import collections
import os

from fragments import Fragment
from generation import GenerationException
from pyparsing import ParseException, Suppress, White


class LinkerScript:
    """
    Process a linker script template, which contains markers with grammar:

    [<target>]

    The <target> is where output commands (see output_commands.py) are placed.
    """

    Marker = collections.namedtuple('Marker', 'target indent rules')

    def __init__(self, template_file):
        self.members = []
        self.file = os.path.realpath(template_file.name)

        self._generate_members(template_file)

    def _generate_members(self, template_file):
        lines = template_file.readlines()

        target = Fragment.IDENTIFIER
        reference = Suppress('mapping') + Suppress('[') + target.setResultsName('target') + Suppress(']')
        pattern = White(' \t').setResultsName('indent') + reference

        # Find the markers in the template file line by line. If line does not match marker grammar,
        # set it as a literal to be copied as is to the output file.
        for line in lines:
            try:
                parsed = pattern.parseString(line)

                indent = parsed.indent
                target = parsed.target

                marker = LinkerScript.Marker(target, indent, [])

                self.members.append(marker)
            except ParseException:
                # Does not match marker syntax
                self.members.append(line)

    def fill(self, mapping_rules):
        for member in self.members:
            target = None
            try:
                target = member.target
                rules = member.rules

                del rules[:]

                rules.extend(mapping_rules[target])
            except KeyError:
                message = GenerationException.UNDEFINED_REFERENCE + " to target '" + target + "'."
                raise GenerationException(message)
            except AttributeError:
                pass

    def write(self, output_file):
        # Add information that this is a generated file.
        output_file.write('/* Automatically generated file; DO NOT EDIT */\n')
        output_file.write('/* Espressif IoT Development Framework Linker Script */\n')
        output_file.write('/* Generated from: %s */\n' % self.file)
        output_file.write('\n')

        # Do the text replacement
        for member in self.members:
            try:
                indent = member.indent
                rules = member.rules

                for rule in rules:
                    generated_line = ''.join([indent, str(rule), '\n'])
                    output_file.write(generated_line)
            except AttributeError:
                output_file.write(member)