import tempfile
import os
from os import path
import sys
import re
import subprocess
from contextlib import contextmanager
from collections import defaultdict
import colorsys

import cxxfilt
from elftools.elf.elffile import ELFFile
from elftools.elf.enums import ENUM_ST_SHNDX
from elftools.elf.descriptions import describe_symbol_type, describe_sh_type
import libarchive
import matplotlib.cm

@contextmanager
def chdir(newdir):
    old_cwd = os.getcwd()
    try:
        os.chdir(newdir)
        yield
    finally:
        os.chdir(old_cwd)


def trace_source_files(linker, cmdline, trace_sections=[]):
    with tempfile.TemporaryDirectory() as tempdir:
        out_path = path.join(tempdir, 'output.elf')
        output = subprocess.check_output([linker, '-o', out_path, f'-Wl,--cref', *cmdline])
        lines = [ line.strip() for line in output.decode().splitlines() ]
        # FIXME also find isr vector table references

        defs = {}
        for line in lines[lines.index('Cross Reference Table')+3:]:
            try:
                *left, right = line.split()
                if left:
                    defs[' '.join(left)] = right 
            except:
                pass

        refs = defaultdict(lambda: set())
        syms = {}
        for sym, obj in defs.items():
            fn, _, member = re.match('^([^()]+)(\((.+)\))?$', obj).groups()
            fn = path.abspath(fn)

            if member:
                subprocess.check_call(['ar', 'x', '--output', tempdir, fn, member])
                fn = path.join(tempdir, member)

            with open(fn, 'rb') as f:
                elf = ELFFile(f)

                symtab = elf.get_section_by_name('.symtab')
                
                symtab_demangled = { cxxfilt.demangle(nsym.name).replace(' ', ''): i
                        for i, nsym in enumerate(symtab.iter_symbols()) }

                def lookup_size(name):
                    name_normalized = name.replace(' ', '')
                    if name_normalized in symtab_demangled:
                        entry = symtab.get_symbol(symtab_demangled[name_normalized])
                        index = entry['st_shndx']
                        if index in ENUM_ST_SHNDX:
                            return 'no bits'
                        sec = elf.get_section(index)
                        if describe_sh_type(sec['sh_type']) == 'NOBITS':
                            return 'no bits'
                        return entry['st_size']
                    else:
                        return None

                syms[sym] = fn, lookup_size(sym)

                s = set()
                sec_map = { sec.name: i for i, sec in enumerate(elf.iter_sections()) }
                matches = [ i for name, i in sec_map.items() if re.match(f'\.rel\..*\.{sym}', name) ]
                if matches:
                    sec = elf.get_section(matches[0])
                    for reloc in sec.iter_relocations():
                        refsym = symtab.get_symbol(reloc['r_info_sym'])
                        name = refsym.name if refsym.name else elf.get_section(refsym['st_shndx']).name.split('.')[-1]
                        s.add(name)
                        
                        if name not in defs:
                            syms[name] = fn, lookup_size(name)
                refs[sym] = s

                for tsec in trace_sections:
                    matches = [ i for name, i in sec_map.items() if name == f'.rel{tsec}' ]
                    s = set()
                    if matches:
                        sec = elf.get_section(matches[0])
                        for reloc in sec.iter_relocations():
                            refsym = symtab.get_symbol(reloc['r_info_sym'])
                            s.add(refsym.name)
                    refs[tsec.replace('.', '_')] |= s

        syms_out = set()
        with open(out_path, 'rb') as f:
            elf = ELFFile(f)
            symtab = elf.get_section_by_name('.symtab')
            for sym in symtab.iter_symbols():
                if describe_symbol_type(sym['st_info']['type']) in ('FUNC', 'OBJECT'):
                    syms_out.add(sym.name)
            #for sym in defs:
            #    entry = symtab.get_symbol_by_name(sym)
            #    if entry is None:
            #        syms[sym] = defs[sym], None
            #    else:
            #        syms[sym] = defs[sym], entry[0]['st_size']

        return syms, refs, syms_out

@contextmanager
def wrap(leader='', print=print, left='{', right='}'):
    print(leader, left)
    yield lambda *args, **kwargs: print('   ', *args, **kwargs)
    print(right)

def mangle(name):
    return re.sub('[^a-zA-Z0-9_]', '_', name)

hexcolor = lambda r, g, b, *_a: f'#{int(r*255):02x}{int(g*255):02x}{int(b*255):02x}'
def vhex(val):
    r,g,b,_a = matplotlib.cm.viridis(1.0-val)
    fc = hexcolor(r, g, b)  
    h,s,v = colorsys.rgb_to_hsv(r,g,b)
    cc = '#000000' if v > 0.8 else '#ffffff'
    return fc, cc

if __name__ == '__main__':
    import argparse
    parser = argparse.ArgumentParser()
    parser.add_argument('--trace-sections', type=str, action='append', default=[])
    parser.add_argument('--trim-stubs', type=str, action='append', default=[])
    parser.add_argument('--highlight-subdirs', type=str, default=None)
    parser.add_argument('linker_binary')
    parser.add_argument('linker_args', nargs=argparse.REMAINDER)
    args = parser.parse_args()

    trace_sections = args.trace_sections
    trace_sections_mangled = { sec.replace('.', '_') for sec in trace_sections }
    syms, refs, syms_out = trace_source_files(args.linker_binary, args.linker_args, trace_sections)

    for name, (obj, size) in syms.items():
        if path.basename(obj) in args.trim_stubs and (not isinstance(size, int) or size <= 8) and not refs.get(name):
            syms_out.discard(name)

    clusters = defaultdict(lambda: [])
    for sym, (obj, size) in syms.items():
        if sym in syms_out:
            clusters[obj].append((sym, size))

    obj_size = defaultdict(lambda: 0)
    for sym, (obj, size) in syms.items():
        if isinstance(size, int) and sym in syms_out:
            obj_size[obj] += size
    max_size = max([ size for _obj, size in syms.values() if isinstance(size, int) ])

    max_osize = max(obj_size.values())

    subdir_prefix = path.abspath(args.highlight_subdirs) + '/' if args.highlight_subdirs else '### NO HIGHLIGHT ###'
    first_comp = lambda le_path: path.dirname(le_path).partition(os.sep)[0]
    subdir_colors = sorted({ first_comp(obj[len(subdir_prefix):]) for obj in obj_size if obj.startswith(subdir_prefix) })
    subdir_colors = { path: hexcolor(*matplotlib.cm.Pastel1(i/len(subdir_colors))) for i, path in enumerate(subdir_colors) }

    subdir_sizes = defaultdict(lambda: 0)
    for obj, size in obj_size.items():
        if not isinstance(size, int):
            continue
        if obj.startswith(subdir_prefix):
            subdir_sizes[first_comp(obj[len(subdir_prefix):])] += size
        else:
            subdir_sizes['<others>'] += size

    print('Subdir sizes:', file=sys.stderr)
    for subdir, size in sorted(subdir_sizes.items(), key=lambda x: x[1]):
        print(f'{subdir:>20}: {size:>6,d} B', file=sys.stderr)

    def lookup_highlight(path):
        if args.highlight_subdirs:
            if obj.startswith(subdir_prefix):
                highlight_head = first_comp(path[len(subdir_prefix):])
                return subdir_colors[highlight_head], highlight_head
            else:
                return '#e0e0e0', None
        else:
            return '#ddf7f4', None

    with wrap('digraph G', print) as lvl1print:
        print('rankdir=LR;')
        print('ranksep=1;')
        print('nodesep=0.2;')
        print()

        for i, (obj, syms) in enumerate(clusters.items()):
            with wrap(f'subgraph cluster_{i}', lvl1print) as lvl2print:
                print('style = "filled";')
                highlight_color, highlight_head = lookup_highlight(obj)
                print(f'bgcolor = "{highlight_color}";')
                print('pencolor = none;')
                fc, cc = vhex(obj_size[obj]/max_osize)
                highlight_subdir_part = f'<font face="carlito" color="{cc}" point-size="12">{highlight_head} / </font>' if highlight_head else ''
                lvl2print(f'label = <<table border="0"><tr><td border="0" cellpadding="5" bgcolor="{fc}">'
                          f'{highlight_subdir_part}'
                          f'<font face="carlito" color="{cc}"><b>{path.basename(obj)} ({obj_size[obj]}B)</b></font>'
                          f'</td></tr></table>>;')
                lvl2print()
                for sym, size in syms:
                    if sym in syms_out:
                        size_s = f'{size}B' if isinstance(size, int) else size
                        fc, cc = vhex(size/max_size if isinstance(size, int) else 0)
                        lvl2print(f'{mangle(sym)}[label = "{sym} ({size_s})", style="rounded,filled", shape="box", fillcolor="{fc}", fontname="carlito", fontcolor="{cc}" color=none];')
            lvl1print()

        for start, ends in refs.items():
            for end in ends:
                if end and (start in syms_out or start in trace_sections_mangled) and end in syms_out:
                    lvl1print(f'{mangle(start)} -> {mangle(end)} [style="bold", color="#333333"];')

        for sec in trace_sections:
            lvl1print(f'{sec.replace(".", "_")} [label = "section {sec}", shape="box", style="filled,bold"];')