import re

from file_util import FileUtil

LD_NAME = 'dkr.ld'
ASM_DIR = './asm'

class LD:
    def __init__(self, file):
        print('Generating linker file...')
        self.files = self.get_asm_files()
        self.indentLevel = 0
        self.file = file
        self.gen_comment('linker script generated by generate_ld.py')
        self.gen_newline()
        self.gen_line('OUTPUT_ARCH (mips)')
        self.gen_newline()
        #self.gen_macros()
        self.gen_sections()
        print('New linker file created!')
    
    def gen_macros(self):
        self.gen_line('#define BEGIN_SEG(name, addr) \\')
        self.increase_indent()
        self.gen_line('_##name##SegmentStart = ADDR(.name); \\')
        self.gen_line('_##name##SegmentRomStart = __romPos; \\')
        self.gen_line('.name addr : AT(__romPos)')
        self.decrease_indent()
        self.gen_newline()
        self.gen_line('#define END_SEG(name) \\')
        self.increase_indent()
        self.gen_line('_##name##SegmentEnd = ADDR(.name) + SIZEOF(.name); \\')
        self.gen_line('_##name##SegmentRomEnd = __romPos + SIZEOF(.name); \\')
        self.gen_line('__romPos += SIZEOF(.name);')
        self.decrease_indent()
        self.gen_newline()
        
    def gen_sections(self):
        self.gen_line('SECTIONS')
        self.gen_open_block()
        self.gen_line('romPos = 0x0;')
        self.gen_boot_section()
        self.gen_main_section()
        self.gen_assets_section()
        self.gen_discard()
        self.gen_close_block()
    
    def gen_boot_section(self):
        self.gen_line('.boot 0 : AT(romPos)')
        self.gen_open_block()
        self.gen_line('build/asm/boot/rom_header.o(.text);')
        self.gen_line('build/asm/boot/rom_boot.o(.text);')
        self.gen_close_block()
        self.gen_line('romPos += SIZEOF(.boot);')
        self.gen_newline()
    
    def gen_main_section(self):
        self.gen_line('.main 0x80000400 : AT(romPos) SUBALIGN(16)')
        self.gen_open_block()
        self.files.sort(key = lambda x: x[2]) # Sort tuples by RAM address
        for asmFile in self.files:
            self.gen_line(asmFile[0] + '.o(.text);')
        self.gen_close_block()
        self.gen_line('romPos += SIZEOF(.main);')
        self.gen_newline()
        
    def gen_assets_section(self):
        self.gen_line('.assets 0 : AT(romPos)')
        self.gen_open_block()
        self.gen_line('build/asm/assets/assets.o(.text);')
        self.gen_close_block()
        self.gen_line('romPos += SIZEOF(.assets);')
        self.gen_newline()
        
    def gen_discard(self):
        self.gen_comment('Discard everything not specifically mentioned above.')
        self.gen_line('/DISCARD/ :')
        self.gen_open_block()
        self.gen_line('*(*);')
        self.gen_close_block()
    
    def increase_indent(self):
        self.indentLevel += 1
    
    def decrease_indent(self):
        self.indentLevel -= 1
        
    def gen_open_block(self):
        self.gen_line('{')
        self.increase_indent()
        
    def gen_close_block(self):
        self.decrease_indent()
        self.gen_line('}')
    
    def gen_line(self, text):
        spaces = 4 * self.indentLevel
        while spaces > 0:
            self.file.write(' ')
            spaces -= 1
        self.file.write(text)
        self.gen_newline()
        
    def gen_comment(self, text):
        spaces = 4 * self.indentLevel
        while spaces > 0:
            self.file.write(' ')
            spaces -= 1
        self.file.write('/* ' + text + ' */')
        self.gen_newline()
        
    def gen_newline(self):
        self.file.write('\n')
        
    def get_asm_files(self):
        asmFiles = []
        asmFilenames = FileUtil.get_filenames_from_directory(ASM_DIR, ('.s',))
        regex = r'[\/][*]\s*([0-9A-F]{6})\s*([0-9A-F]{8})\s*([0-9A-F]{8})\s*[*][\/]'
        for filename in asmFilenames:
            with open(ASM_DIR + '/' + filename, 'r') as asmFile:
                notDone = True
                line = asmFile.readline()
                while line:
                    matches = re.match(regex, line)
                    if matches is None:
                        line = asmFile.readline()
                        continue
                    matchedGroups = matches.groups()
                    asmFiles.append(('build/asm/' + filename[:-2], matchedGroups[0], matchedGroups[1]))
                    break
        return asmFiles
            
        
with open(LD_NAME, 'w') as ldFile:
    LD(ldFile)