#! /usr/bin/env python
# -*- coding: utf-8 -*-
#
# Copyright 2014 Hamilton Kibbe <ham@hamiltonkib.be>
# Copyright 2021 Jan Götte <code@jaseg.de>
#
# 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 os
import re
import warnings
from collections import namedtuple
from pathlib import Path

from .excellon import ExcellonFile
from .rs274x import GerberFile
from .ipc356 import Netlist
from .cam import FileSettings
from .layer_rules import MATCH_RULES


STANDARD_LAYERS = [
        'mechanical outline',
        'top copper',
        'top mask',
        'top silk',
        'top paste',
        'bottom copper',
        'bottom mask',
        'bottom silk',
        'bottom paste',
        ]


def match_files(filenames):
    matches = {}
    for generator, rules in MATCH_RULES.items():
        gen = {}
        matches[generator] = gen
        for layer, regex in rules.items():
            for fn in filenames:
                if (m := re.fullmatch(regex, fn.name, re.IGNORECASE)):
                    if layer == 'inner copper':
                        target = 'inner_' + ''.join(e or '' for e in m.groups()) + ' copper'
                    else:
                        target = layer
                    gen[target] = gen.get(target, []) + [fn]
    return matches

def best_match(filenames):
    matches = match_files(filenames)
    matches = sorted(matches.items(), key=lambda pair: len(pair[1]))
    generator, files = matches[-1]
    return generator, files

def identify_file(data):
    if 'M48' in data:
        return 'excellon'

    if 'G90' in data and ';LEADER:' in data: # yet another allegro special case
        return 'excellon'

    if 'FSLAX' in data or 'FSTAX' in data:
        return 'gerber'

    if 'UNITS CUST' in data:
        return 'ipc356'

    return None

def common_prefix(l):
    out = []
    for cand in l:
        score = lambda n: sum(elem.startswith(cand[:n]) for elem in l)
        baseline = score(1)
        if len(l) - baseline > 5:
            continue
        for n in range(2, len(cand)):
            if len(l) - score(n) > 5:
                break
        out.append(cand[:n-1])
 
    if not out:
        return ''
 
    return sorted(out, key=len)[-1]

def autoguess(filenames):
    prefix = common_prefix([f.name for f in filenames])

    matches = {}
    for f in filenames:
        name = layername_autoguesser(f.name[len(prefix):] if f.name.startswith(prefix) else f.name)
        if name != 'unknown unknown':
            matches[name] = matches.get(name, []) + [f]

    inner_layers = [ m for m in matches if 'inner' in m ]
    if len(inner_layers) >= 4 and 'copper top' not in matches and 'copper bottom' not in matches:
        if 'inner_01 copper' in matches:
            warnings.warn('Could not find copper layer. Re-assigning outermost inner layers to top/bottom copper.')
            matches['top copper'] = matches.pop('inner_01 copper')
            last_inner = sorted(inner_layers, key=lambda name: int(name.partition(' ')[0].partition('_')[2]))[-1]
            matches['bottom copper'] = matches.pop(last_inner)

    return matches

def layername_autoguesser(fn):
    fn, _, ext = fn.lower().rpartition('.')
    
    if ext in ('log', 'err'):
        return 'unknown unknown'

    side, use = 'unknown', 'unknown'
    if re.search('top|front|pri?m?(ary)?', fn):
        side = 'top'
        use = 'copper'
    if re.search('bot(tom)?|back|sec(ondary)?', fn):
        side = 'bottom'
        use = 'copper'

    if re.search('silks?(creen)?', fn):
        use = 'silk'

    elif re.search('(solder)?paste', fn):
        use = 'paste'

    elif re.search('(solder)?mask', fn):
        use = 'mask'

    elif re.search('drill|rout?e?', fn):
        use = 'drill'
        side = 'unknown'

        if re.search(r'np(th)?|(non|un)\W*plated|(non|un)\Wgalv', fn):
            side = 'nonplated'

        elif re.search('pth|plated|galv', fn):
            side = 'plated'

    elif (m := re.search(r'(la?y?e?r?|in(ner)?)\W*(?P<num>[0-9]+)', fn)):
        use = 'copper'
        side = f'inner_{int(m["num"]):02d}'

    elif re.search('film', fn):
        use = 'copper'

    elif re.search('out(line)?', fn):
        use = 'outline'
        side = 'mechanical'

    elif 'ipc' in fn and '356' in fn:
        use = 'netlist'
        side = 'other'

    elif 'netlist' in fn:
        use = 'netlist'
        side = 'other'

    return f'{side} {use}'

class LayerStack:
    @classmethod
    def from_directory(kls, directory, board_name=None, verbose=False):

        directory = Path(directory)
        if not directory.is_dir():
            raise FileNotFoundError(f'{directory} is not a directory')

        files = [ path for path in directory.glob('**/*') if path.is_file() ]
        generator, filemap = best_match(files)
        print('detected generator', generator)

        if len(filemap) < 6:
            warnings.warn('Ambiguous gerber filenames. Trying last-resort autoguesser.')
            generator = None
            filemap = autoguess(files)
            if len(filemap) < 6:
                raise ValueError('Cannot figure out gerber file mapping. Partial map is: ', filemap)

        if generator == 'geda':
            # geda is written by geniuses who waste no bytes of unnecessary output so it doesn't actually include the
            # number format in files that use imperial units. Unfortunately it also doesn't include any hints that the
            # file was generated by geda, so we have to guess by context whether this is just geda being geda or
            # potential user error.
            excellon_settings = FileSettings(number_format=(2, 4))

        elif generator == 'allegro':
            # Allegro puts information that is absolutely vital for parsing its excellon files... into another file,
            # next to the actual excellon file. Despite pretty much everyone else having figured out a way to put that
            # info into the excellon file itself, even if only as a comment.
            if 'excellon params' in filemap:
                excellon_settings = parse_allegro_ncparam(filemap['excellon params'][0].read_text())
                del filemap['excellon params']
            # Ignore if we can't find the param file -- maybe the user has convinced Allegro to actually put this
            # information into a comment, or maybe they have made Allegro just use decimal points like XNC does.

            filemap = autoguess([ f for files in filemap for f in files ])
            if len(filemap < 6):
                raise SystemError('Cannot figure out gerber file mapping')
            # FIXME use layer metadata from comments and ipc file if available

        elif generator == 'altium':
            excellon_settings = None

            if 'mechanical outline' in filemap:
                # Use lowest-numbered mechanical layer as outline, ignore others.
                mechs = {}
                for layer in filemap['mechanical outline']:
                    if layer.name.lower().endswith('gko'):
                        filemap['mechanical outline'] = [layer]
                        break

                    if (m := re.match(r'.*\.gm([0-9]+)', layer.name, re.IGNORECASE)):
                        mechs[int(m[1])] = layer
                    else:
                        break
                else:
                    filemap['mechanical outline'] = [sorted(mechs.items(), key=lambda x: x[0])[0][1]]

        else:
            excellon_settings = None

        import pprint
        pprint.pprint(filemap)

        ambiguous = [ key for key, value in filemap.items() if len(value) > 1 and not 'drill' in key ]
        if ambiguous:
            raise SystemError(f'Ambiguous layer names for {", ".join(ambiguous)}')

        drill_layers = []
        netlist = None
        layers = {} # { tuple(key.split()): None for key in STANDARD_LAYERS }
        for key, paths in filemap.items():
            if len(paths) > 1 and not 'drill' in key:
                raise ValueError(f'Multiple matching files found for {key} layer: {", ".join(value)}')

            for path in paths:
                id_result = identify_file(path.read_text())
                print('id_result', id_result)

                if 'netlist' in key:
                    layer = Netlist.open(path)

                elif ('outline' in key or 'drill' in key) and id_result != 'gerber':
                    if id_result is None:
                        # Since e.g. altium uses ".txt" as the extension for its drill files, we have to assume the
                        # current file might not be a drill file after all.
                        continue

                    if 'nonplated' in key:
                        plated = False
                    elif 'plated' in key:
                        plated = True
                    else:
                        plated = None
                    layer = ExcellonFile.open(path, plated=plated, settings=excellon_settings)
                else:

                    layer = GerberFile.open(path)

                if key == 'mechanical outline':
                    layers['mechanical', 'outline'] = layer

                elif 'drill' in key:
                    drill_layers.append(layer)

                elif 'netlist' in key:
                    if netlist:
                        warnings.warn(f'Found multiple netlist files, using only first one. Have: {netlist.original_path.name}, got {path.name}')
                    else:
                        netlist = layer

                else:
                    side, _, use = key.partition(' ')
                    layers[(side, use)] = layer

                hints = set(layer.generator_hints) | { generator }
                if len(hints) > 1:
                    warnings.warn('File identification returned ambiguous results. Please raise an issue on the gerbonara '
                            'tracker and if possible please provide these input files for reference.')

        board_name = common_prefix([l.original_path.name for l in layers.values() if l is not None])
        board_name = re.sub(r'^\W+', '', board_name)
        board_name = re.sub(r'\W+$', '', board_name)
        return kls(layers, drill_layers, netlist, board_name=board_name)

    def __init__(self, graphic_layers, drill_layers, netlist=None, board_name=None):
        self.graphic_layers = graphic_layers
        self.drill_layers = drill_layers
        self.board_name = board_name
        self.netlist = netlist

    def __str__(self):
        names = [ f'{side} {use}' for side, use in self.graphic_layers ]
        return f'<LayerStack {self.board_name} [{", ".join(names)}] and {len(self.drill_layers)} drill layers>'

    def __repr__(self):
        return str(self)

    def merge_drill_layers(self):
        target = ExcellonFile(comments='Drill files merged by gerbonara')

        for layer in self.drill_layers:
            if isinstance(layer, GerberFile):
                layer = layer.to_excellon()

            target.merge(layer)

        self.drill_layers = [target]

    def normalize_drill_layers(self):
        # TODO: maybe also separate into drill and route?
        drill_pth, drill_npth, drill_aux = [], [], []

        for layer in self.drill_layers:
            if isinstance(layer, GerberFile):
                layer = layer.to_excellon()

            if layer.is_plated:
                drill_pth.append(layer)
            elif layer.is_nonplated:
                drill_pth.append(layer)
            else:
                drill_aux.append(layer)
        
        pth_out, *rest = drill_pth or [ExcellonFile()]
        for layer in rest:
            pth_out.merge(layer)

        npth_out, *rest = drill_npth or [ExcellonFile()]
        for layer in rest:
            npth_out.merge(layer)

        unknown_out = ExcellonFile()
        for layer in drill_aux:
            for obj in layer.objects:
                if obj.plated is None:
                    unknown_out.append(obj)
                elif obj.plated:
                    pth_out.append(obj)
                else:
                    npth_out.append(obj)

        self.drill_pth, self.drill_npth = pth_out, npth_out
        self.drill_unknown = unknown_out if unknown_out else None
        self._drill_layers = []

    @property
    def drill_layers(self):
        if self._drill_layers:
            return self._drill_layers
        if self.drill_pth or self.drill_npth or self.drill_unknown:
            return [self.drill_pth, self.drill_npth, self.drill_unknown]
        return []

    @drill_layers.setter
    def drill_layers(self, value):
        self._drill_layers = value
        self.drill_pth = self.drill_npth = self.drill_unknown = None

    def __len__(self):
        return len(self.layers)

    def get(self, index, default=None):
        if self.contains(key):
            return self[key]
        else:
            return default

    def __contains__(self, index):
        if isinstance(index, str):
            side, _, use = index.partition(' ')
            return (side, use) in self.layers

        elif isinstance(index, tuple):
            return index in self.graphic_layers

        return index < len(self.copper_layers)

    def __getitem__(self, index):
        if isinstance(index, str):
            side, _, use = index.partition(' ')
            return self.graphic_layers[(side, use)]

        elif isinstance(index, tuple):
            return self.graphic_layers[index]

        return self.copper_layers[index]

    @property
    def copper_layers(self):
        copper_layers = [ (key, layer) for key, layer in self.layers.items() if key.endswith('copper') ]

        def sort_layername(val):
            key, _layer = val
            if key.startswith('top'):
                return -1
            if key.startswith('bottom'):
                return 1e99
            assert key.startswith('inner_')
            return int(key[len('inner_'):])

        return [ layer for _key, layer in sorted(copper_layers, key=sort_layername) ]

    @property
    def top_side(self):
        return { key: self[key] for key in ('top copper', 'top mask', 'top silk', 'top paste', 'mechanical outline') }

    @property
    def bottom_side(self):
        return { key: self[key] for key in ('bottom copper', 'bottom mask', 'bottom silk', 'bottom paste', 'mechanical outline') }

    @property
    def outline(self):
        return self['mechanical outline']
    
    def _merge_layer(self, target, source):
        if source is None:
            return
        
        if self[target] is None:
            self[target] = source

        else:
            self[target].merge(source)

    def merge(self, other):
        all_keys = set(self.layers.keys()) | set(other.layers.keys())
        exclude = { key.split() for key in STANDARD_LAYERS }
        all_keys = { key for key in all_keys if key not in exclude }
        if all_keys:
            warnings.warn('Cannot merge unknown layer types: {" ".join(all_keys)}')

        for side in 'top', 'bottom':
            for use in 'copper', 'mask', 'silk', 'paste':
                self._merge_layer((side, use), other[side, use])

        our_inner, their_inner = self.copper_layers[1:-1], other.copper_layers[1:-1]

        if bool(our_inner) != bool(their_inner):
            warnings.warn('Merging board without inner layers into board with inner layers, inner layers will be empty on first board.')

        elif our_inner and their_inner:
            warnings.warn('Merging boards with different inner layer counts. Will fill inner layers starting at core.')

        diff = len(our_inner) - len(their_inner)
        their_inner = ([None] * max(0, diff//2)) + their_inner + ([None] * max(0, diff//2))
        our_inner = ([None] * max(0, -diff//2)) + their_inner + ([None] * max(0, -diff//2))

        new_inner = []
        for ours, theirs in zip(our_inner, their_inner):
            if ours is None:
                new_inner.append(theirs)
            elif theirs is None:
                new_inner.append(ours)
            else:
                ours.merge(theirs)
                new_inner.append(ours)

        for i, layer in enumerate(new_inner, start=1):
            self[f'inner_{i} copper'] = layer

        self._merge_layer('mechanical outline', other['mechanical outline'])

        self.normalize_drill_layers()
        other.normalize_drill_layers()

        self.drill_pth.merge(other.drill_pth)
        self.drill_npth.merge(other.drill_npth)
        self.drill_unknown.merge(other.drill_unknown)
        self.netlist.merge(other.netlist)