# -*- coding: utf-8 -*-
# Copyright (c) 2022 Salvador E. Tropea
# Copyright (c) 2022 Instituto Nacional de Tecnología Industrial
# License: GPL-3.0
# Project: KiBot (formerly KiPlot)
"""
Dependencies:
  - name: KiCad PCB/SCH Diff
    version: 2.4.3
    role: mandatory
    github: INTI-CMNB/KiDiff
    command: kicad-diff.py
    pypi: kidiff
    downloader: pytool
    id: KiDiff
  - from: Git
    role: Compare with files in the repo
  - from: KiAuto
    role: Compare schematics
    version: 2.0.0
"""
from hashlib import sha1
from itertools import combinations
import os
import re
from shutil import rmtree, copy2
from subprocess import CalledProcessError
from tempfile import mkdtemp, NamedTemporaryFile
from .error import KiPlotConfigurationError
from .gs import GS
from .kiplot import load_any_sch, run_command, config_output, get_output_dir, run_output
from .layer import Layer
from .misc import DIFF_TOO_BIG, FAILED_EXECUTE
from .optionable import BaseOptions
from .out_base import VariantOptions
from .registrable import RegOutput
from .macros import macros, document, output_class  # noqa: F401
from . import log

logger = log.get_logger()
STASH_MSG = 'KiBot_Changes_Entry'


class DiffOptions(BaseOptions):
    def __init__(self):
        with document:
            self.output = GS.def_global_output
            """ *Filename for the output (%i=diff_pcb/diff_sch, %x=pdf) """
            self.pcb = True
            """ Compare the PCB, otherwise compare the schematic """
            self.old = 'HEAD'
            """ Reference file. When using git use `HEAD` to refer to the last commit.
                Use `HEAD~` to refer the previous to the last commit.
                As `HEAD` is for the whole repo you can use `KIBOT_LAST-n` to make
                reference to the changes in the PCB/SCH. The `n` value is how many
                changes in the history you want to go back. A 0 is the same as `HEAD`,
                a 1 means the last time the PCB/SCH was changed, etc.
                Use `KIBOT_TAG-n` to search for the last tag skipping `n` tags.
                Important: when using the `checkout` GitHub action you just get the
                last commit. To clone the full repo use `fetch-depth: '0'` """
            self.old_type = 'git'
            """ [git,file,output,multivar] How to interpret the `old` name. Use `git` for a git hash, branch, etc.
                Use `file` for a file name. Use `output` to specify the name of a `pcb_variant`/`sch_variant` output.
                Use `multivar` to specify a reference file when `new_type` is also `multivar` """
            self.new = ''
            """ [string|list(string)] The file you want to compare. Leave it blank for the current PCB/SCH.
                A list is accepted only for the `multivar` type. Consult the `old` option for more information """
            self.new_type = 'current'
            """ [git,file,output,multivar,current] How to interpret the `new` name. Use `git` for a git hash, branch, etc.
                Use `current` for the currently loaded PCB/Schematic.
                Use `file` for a file name. Use `output` to specify the name of a `pcb_variant`/`sch_variant` output.
                Use `multivar` to compare a set of variants, in this mode `new` is the list of outputs for the variants.
                This is an extension of the `output` mode.
                If `old` is also `multivar` then it becomes the reference, otherwise we compare using pairs of variants """
            self.cache_dir = ''
            """ Directory to cache the intermediate files. Leave it blank to disable the cache """
            self.diff_mode = 'red_green'
            """ [red_green,stats] In the `red_green` mode added stuff is green and red when removed.
                The `stats` mode is used to meassure the amount of difference. In this mode all
                changes are red, but you can abort if the difference is bigger than certain threshold """
            self.fuzz = 5
            """ [0,100] Color tolerance (fuzzyness) for the `stats` mode """
            self.threshold = 0
            """ [0,1000000] Error threshold for the `stats` mode, 0 is no error. When specified a
                difference bigger than the indicated value will make the diff fail.
                KiBot will return error level 29 and the diff generation will be aborted """
            self.add_link_id = False
            """ When enabled we create a symlink to the output file with a name that contains the
                git hashes involved in the comparison. If you plan to compress the output don't
                forget to disable the `follow_links` option """
            self.copy_instead_of_link = False
            """ Modifies the behavior of `add_link_id` to create a copy of the file instead of a
                symlink. Useful for some Windows setups """
            self.force_checkout = False
            """ When `old_type` and/or `new_type` are `git` KiBot will checkout the indicated point.
                Before doing it KiBot will stash any change. Under some circumstances git could fail
                to do a checkout, even after stashing, this option can workaround the problem.
                Note that using it you could potentially lose modified files. For more information
                read https://stackoverflow.com/questions/1248029/git-pull-error-entry-foo-not-uptodate-cannot-merge """
            self.use_file_id = False
            """ When creating the link name of an output file related to a variant use the variant
                `file_id` instead of its name """
            self.only_different = False
            """ Only include the pages with differences in the output PDF.
                Note that when no differeces are found we get a page saying *No diff* """
            self.only_first_sch_page = False
            """ Compare only the main schematic page (root page) """
            self.always_fail_if_missing = False
            """ Always fail if the old/new file doesn't exist. Currently we don't fail if they are from a repo.
                So if you refer to a repo point where the file wasn't created KiBot will use an empty file.
                Enabling this option KiBot will report an error """
        super().__init__()
        self._expand_id = 'diff'
        self._expand_ext = 'pdf'

    def config(self, parent):
        super().config(parent)
        self._expand_id = 'diff'+('_pcb' if self.pcb else '_sch')
        if self.new_type == 'multivar':
            if isinstance(self.new, str):
                raise KiPlotConfigurationError('`new` must be a list when using the `multivar` type')
            if len(self.new) < 2:
                raise KiPlotConfigurationError('`new` must contain at least two variants when using the `multivar` type')
        else:
            if isinstance(self.new, list):
                raise KiPlotConfigurationError('`new` must be a single string for `{}` type'.format(self.new_type))
        if self.old_type == 'multivar' and self.new_type != 'multivar':
            raise KiPlotConfigurationError("`old_type` can't be `multivar` when `new_type` isn't (`{}`)".format(self.new_type))

    def get_targets(self, out_dir):
        return [self._parent.expand_filename(out_dir, self.output)]

    def get_digest(self, file_path, restart=True):
        logger.debug('Hashing '+file_path)
        if restart:
            self.h = sha1()
        with open(file_path, 'rb') as file:
            while True:
                chunk = file.read(self.h.block_size)
                if not chunk:
                    break
                self.h.update(chunk)
        return self.h.hexdigest()

    def add_to_cache(self, name, hash):
        cmd = [self.command, '--no_reader', '--only_cache', '--old_file_hash', hash, '--cache_dir', self.cache_dir]
        if self.incl_file:
            cmd.extend(['--layers', self.incl_file])
        if not self.only_first_sch_page:
            cmd.append('--all_pages')
        if GS.debug_enabled:
            cmd.insert(1, '-'+'v'*GS.debug_level)
        cmd.extend([name, name])
        self.name_used_for_cache = name
        run_command(cmd)

    def cache_pcb(self, name):
        if name:
            if not os.path.isfile(name):
                raise KiPlotConfigurationError('Missing file to compare: `{}`'.format(name))
        else:
            GS.check_pcb()
            name = GS.pcb_file
            if not os.path.isfile(name):
                if self.always_fail_if_missing:
                    raise KiPlotConfigurationError('Missing file to compare: `{}`'.format(name))
                with NamedTemporaryFile(mode='w', suffix='.kicad_pcb', delete=False) as f:
                    f.write("(kicad_pcb (version 20171130) (host pcbnew 5.1.5))\n")
                    name = f.name
                    self._to_remove.append(name)
        hash = self.get_digest(name)
        self.add_to_cache(name, hash)
        return hash

    def cache_sch(self, name):
        if name:
            if not os.path.isfile(name):
                raise KiPlotConfigurationError('Missing file to compare: `{}`'.format(name))
        else:
            GS.check_sch()
            name = GS.sch_file
            ext = os.path.splitext(name)[1]
            if not os.path.isfile(name):
                if self.always_fail_if_missing:
                    raise KiPlotConfigurationError('Missing file to compare: `{}`'.format(name))
                with NamedTemporaryFile(mode='w', suffix=ext, delete=False) as f:
                    logger.debug('Creating empty schematic: '+f.name)
                    if ext == '.kicad_sch':
                        f.write("(kicad_sch (version 20211123) (generator eeschema))\n")
                    else:
                        f.write("EESchema Schematic File Version 4\nEELAYER 30 0\nEELAYER END\n$Descr A4 11693 8268\n"
                                "$EndDescr\n$EndSCHEMATC\n")
                    name = f.name
                    self._to_remove.append(name)
                if ext != '.kicad_sch':
                    lib_name = os.path.splitext(name)[0]+'-cache.lib'
                    if not os.path.isfile(lib_name):
                        logger.debug('Creating dummy cache lib: '+lib_name)
                        with open(lib_name, 'w') as f:
                            f.write("EESchema-LIBRARY Version 2.4\n#\n#End Library\n")
                        self._to_remove.append(lib_name)
        # Schematics can have sub-sheets
        sch = load_any_sch(name, os.path.splitext(os.path.basename(name))[0])
        files = sch.get_files()
        hash = self.get_digest(files[0])
        if len(files) > 1:
            for f in files[1:]:
                hash = self.get_digest(f, restart=False)
        hash = 'sch'+hash
        self.add_to_cache(name, hash)
        return hash

    def cache_file(self, name=None):
        self.git_hash = 'Current' if not name else 'FILE'
        return self.cache_pcb(name) if self.pcb else self.cache_sch(name)

    def run_git(self, cmd, cwd=None, just_raise=False):
        if cwd is None:
            cwd = self.repo_dir
        return run_command([self.git_command]+cmd, change_to=cwd, just_raise=just_raise)

    def stash_pop(self, cwd=None):
        # We don't know if we stashed anything (push always returns 0)
        # So we check that the last stash contains our message
        res = self.run_git(['stash', 'list', 'stash@{0}'], cwd)
        if STASH_MSG in res:
            self.run_git(['stash', 'pop', '--index'], cwd)

    def git_submodules(self):
        res = self.run_git(['submodule'])
        reg = re.compile(r'^\s*([\da-z]+)\s+(\S+)\s+')
        subs = []
        for ln in res.split('\n'):
            rm = reg.search(ln)
            if rm:
                subm = os.path.join(self.repo_dir, rm.group(2))
                subs.append(subm)
                if not os.path.isdir(subm):
                    KiPlotConfigurationError('Missing git submodule `{}`'.format(subm))
        logger.debug('Git submodules '+str(subs))
        return subs

    def undo_git(self):
        if self.checkedout:
            logger.debug('Restoring point '+self.branch)
            self.run_git(['checkout', '--force', '--recurse-submodules', self.branch])
        if self.stashed:
            logger.debug('Restoring changes')
            self.stash_pop()
            # Do the same for each submodule
            for sub in self.git_submodules():
                self.stash_pop(sub)

    def solve_kibot_magic(self, name, tag):
        # The magic KIBOT_*
        ori = name
        malformed = 'Malformed `{0}` value, must be `{0}-n`, not: {1}'.format(tag, ori)
        name = name[len(tag):]
        # How many changes?
        num = 0
        if len(name):
            if name[0] != '-':
                raise KiPlotConfigurationError(malformed)
            try:
                num = int(name[1:])
            except ValueError:
                raise KiPlotConfigurationError(malformed)
        num = str(num)
        # Return its hash
        if tag == 'KIBOT_LAST':
            res = self.run_git(['log', '--pretty=format:%H', '--skip='+num, '-n', '1', '--', self.file])
        else:  # KIBOT_TAG
            res = self.run_git(['rev-list', '--tags', '--skip='+num, '--max-count=1'])
        if not res:
            raise KiPlotConfigurationError("The `{}` doesn't resolve to a valid hash".format(ori))
        logger.debug('- '+res)
        return res

    def solve_git_name(self, name):
        logger.debug('Finding '+name)
        if name.startswith('KIBOT_LAST'):
            return self.solve_kibot_magic(name, 'KIBOT_LAST')
        if name.startswith('KIBOT_TAG'):
            return self.solve_kibot_magic(name, 'KIBOT_TAG')
        return name

    def get_git_point_desc(self, user_name):
        # Are we at a tagged point?
        name = None
        try:
            name = self.run_git(['describe', '--exact-match', '--tags', 'HEAD'], just_raise=True)
            if user_name == 'Dirty':
                name += '-dirty'
        except CalledProcessError:
            logger.debug("Not at a tag point")
        if name is None:
            # Are we at the HEAD of a branch?
            branch = self.run_git(['rev-parse', '--abbrev-ref', 'HEAD'])
            if branch == 'HEAD':
                # Detached state
                # Try to find the name relative to a tag
                try:
                    name = self.run_git(['describe', '--tags', '--dirty'], just_raise=True)
                except CalledProcessError:
                    logger.debug("Can't find a tag name")
                if not name:
                    # Nothing usable, use what the user specified
                    name = user_name
            else:
                # We are at the HEAD of a branch
                name = branch
                # Do we have a tag in this branch
                extra = None
                try:
                    extra = self.run_git(['describe', '--tags', '--abbrev=0', '--dirty'], just_raise=True)
                except CalledProcessError:
                    logger.debug("Can't find a tag name")
                if extra:
                    name += '['+extra+']'
                elif user_name == 'Dirty':
                    name += '-dirty'
        return '{}({})'.format(self.run_git(['rev-parse', '--short', 'HEAD']), name)

    def git_dirty(self):
        return self.run_git(['status', '--porcelain', '-uno'])

    def cache_git(self, name):
        self.stashed = False
        self.checkedout = False
        # Which file
        if self.pcb:
            GS.check_pcb()
            self.file = GS.pcb_file
        else:
            GS.check_sch()
            self.file = GS.sch_file
        # Place where we know we have a repo
        self.repo_dir = os.path.dirname(os.path.abspath(self.file))
        try:
            if name:
                # Save current changes
                logger.debug('Saving current changes')
                self.run_git(['stash', 'push', '-m', STASH_MSG])
                self.stashed = True
                #  Also save the submodules
                self.run_git(['submodule', 'foreach', 'git stash push -m '+STASH_MSG])
                # Find the current branch
                self.branch = self.run_git(['rev-parse', '--abbrev-ref', 'HEAD'])
                if self.branch == 'HEAD':
                    # Detached
                    self.branch = self.run_git(['rev-parse', 'HEAD'])
                logger.debug('Current branch is '+self.branch)
                # Checkout the target
                name_ori = name
                name = self.solve_git_name(name)
                logger.debug('Changing to '+name)
                ops = ['checkout']
                if self.force_checkout:
                    ops.append('--force')
                self.run_git(ops+['--recurse-submodules', name])
                self.checkedout = True
            else:
                name_ori = 'Dirty' if self.git_dirty() else 'HEAD'
            # Populate the cache
            hash = self.cache_file()
            # A short version of the current hash
            self.git_hash = self.get_git_point_desc(name_ori)
        finally:
            self.undo_git()
        return hash

    @staticmethod
    def check_output_type(out, must_be):
        if out.type != must_be:
            raise KiPlotConfigurationError('Output `{}` must be `{}` type, not `{}`'.format(out.name, must_be, out.type))

    def cache_output(self, name):
        logger.debugl(2, 'From output `{}`'.format(name))
        out = RegOutput.get_output(name)
        if out is None:
            raise KiPlotConfigurationError('Unknown output `{}`'.format(name))
        self.check_output_type(out, 'pcb_variant' if self.pcb else 'sch_variant')
        config_output(out)
        out_dir = get_output_dir(out.dir, out, dry=True)
        if self.pcb:
            fname = out.get_targets(out_dir)[0]
        else:
            fname = out.get_output_sch_name(out_dir)
        logger.debug('File from output {} is {}'.format(name, fname))
        if not out._done:
            run_output(out)
        res = self.cache_file(fname)
        self.git_hash = out.options.variant.file_id if self.use_file_id else out.options.variant.name+'_variant'
        return res

    def cache_current(self):
        """ The file as we interpreted it """
        if self.pcb:
            fname, dir_name = VariantOptions.save_tmp_dir_board('diff')
        else:
            dir_name = mkdtemp()
            self.dirs_to_remove.append(dir_name)
            fname = GS.sch.save_variant(dir_name)
        res = self.cache_file(os.path.join(dir_name, fname))
        self.git_hash = 'Current'
        return res

    def cache_obj(self, name, type):
        if type == 'git':
            return self.cache_git(name)
        if type == 'file':
            return self.cache_file(name)
        if type == 'current':
            return self.cache_current()
        return self.cache_output(name)

    def create_layers_incl(self, layers):
        incl_file = None
        if self.pcb and not isinstance(layers, type):
            layers = Layer.solve(layers)
            logger.debug('Including layers:')
            with NamedTemporaryFile(mode='w', suffix='.lst', delete=False) as f:
                incl_file = f.name
                for la in layers:
                    logger.debug('- {} ({})'.format(la.layer, la.id))
                    f.write(str(la.id)+'\n')
        return incl_file

    def do_compare(self, old, old_type, new, new_type, name, name_ori):
        dir_name = os.path.dirname(name)
        file_name = os.path.basename(name)
        # Populate the cache
        old_hash = self.cache_obj(old, old_type)
        gh1 = self.git_hash
        name_used_for_old = self.name_used_for_cache
        new_hash = self.cache_obj(new, new_type)
        gh2 = self.git_hash
        name_used_for_new = self.name_used_for_cache
        # Compute the diff using the cache
        cmd = [self.command, '--no_reader', '--new_file_hash', new_hash, '--old_file_hash', old_hash,
               '--cache_dir', self.cache_dir, '--output_dir', dir_name, '--output_name', file_name,
               '--diff_mode', self.diff_mode, '--fuzz', str(self.fuzz), '--no_exist_check']
        if self.incl_file:
            cmd.extend(['--layers', self.incl_file])
        if self.threshold:
            cmd.extend(['--threshold', str(self.threshold)])
        if self.only_different:
            cmd.append('--only_different')
        if not self.only_first_sch_page:
            cmd.append('--all_pages')
        cmd.extend([name_used_for_old, name_used_for_new])
        if GS.debug_enabled:
            cmd.insert(1, '-'+'v'*GS.debug_level)
        try:
            run_command(cmd, just_raise=True)
        except CalledProcessError as e:
            if e.returncode == 10:
                logger.error('Diff above the thresold')
                exit(DIFF_TOO_BIG)
            logger.error('Running {} returned {}'.format(e.cmd, e.returncode))
            if e.stdout:
                logger.debug('- Output from command: '+e.stdout.decode())
            exit(FAILED_EXECUTE)
        if self.add_link_id:
            name_comps = os.path.splitext(name_ori)
            target = name_comps[0]+'_'+gh1+'-'+gh2+name_comps[1]
            if self.copy_instead_of_link:
                copy2(name, target)
            else:
                if os.path.isfile(target):
                    os.remove(target)
                os.symlink(os.path.basename(name), target)

    def run(self, name):
        self.command = self.ensure_tool('KiDiff')
        self._to_remove = []
        if self.old_type == 'git' or self.new_type == 'git':
            self.git_command = self.ensure_tool('Git')
        if not self.pcb:
            # We need eeschema_do for this
            self.ensure_tool('KiAuto')
        # Solve the cache dir
        self.dirs_to_remove = []
        if not self.cache_dir:
            self.cache_dir = mkdtemp()
            self.dirs_to_remove.append(self.cache_dir)
        self.incl_file = None
        name_ori = name
        try:
            # List of layers
            self.incl_file = self.create_layers_incl(self.layers)
            if self.new_type == 'multivar' and self.old_type != 'multivar':
                # Special case, we generate various files
                base_id = self._expand_id
                for pair in combinations(self.new, 2):
                    logger.debug('Using variants '+str(pair))
                    logger.info(' - {} vs {}'.format(pair[0], pair[1]))
                    self._expand_id = '{}_variants_{}_VS_{}'.format(base_id, pair[0], pair[1])
                    name = self._parent.expand_filename(self._parent.output_dir, self.output)
                    self.do_compare(pair[0], 'output', pair[1], 'output', name, name_ori)
                self._expand_id = base_id
            elif self.new_type == 'multivar' and self.old_type == 'multivar':
                # Special case, we generate various files
                base_id = self._expand_id
                for new_variant in self.new:
                    ref_name = self.old if self.old else 'current'
                    logger.info(' - {} vs {}'.format(ref_name, new_variant))
                    self._expand_id = '{}_variant_{}'.format(base_id, new_variant)
                    name = self._parent.expand_filename(self._parent.output_dir, self.output)
                    self.do_compare(self.old, 'file', new_variant, 'output', name, name_ori)
                self._expand_id = base_id
            else:
                self.do_compare(self.old, self.old_type, self.new, self.new_type, name, name_ori)
        finally:
            # Clean-up
            for d in self.dirs_to_remove:
                rmtree(d)
            if self.incl_file:
                os.remove(self.incl_file)
            for f in self._to_remove:
                os.remove(f)


@output_class
class Diff(BaseOutput):  # noqa: F821
    """ Diff
        Generates a PDF with the differences between two PCBs or schematics.
        Recursive git submodules aren't supported (submodules inside submodules) """
    def __init__(self):
        super().__init__()
        self._category = ['PCB/docs', 'Schematic/docs']
        self._both_related = True
        with document:
            self.options = DiffOptions
            """ *[dict] Options for the `diff` output """
            self.layers = Layer
            """ *[list(dict)|list(string)|string] [all,selected,copper,technical,user]
                List of PCB layers to use. When empty all available layers are used.
                Note that if you want to support adding/removing layers you should specify a list here """

    @staticmethod
    def layer2dict(la):
        return {'layer': la.layer, 'suffix': la.suffix, 'description': la.description}

    @staticmethod
    def has_repo(git_command, file):
        try:
            run_command([git_command, 'ls-files', '--error-unmatch', file], change_to=os.path.dirname(file), just_raise=True)
        except CalledProcessError:
            logger.debug("File `{}` not inside a repo".format(file))
            return False
        return True

    @staticmethod
    def get_conf_examples(name, layers, templates):
        outs = []
        git_command = GS.check_tool(name, 'Git')
        if GS.pcb_file and Diff.has_repo(git_command, GS.pcb_file):
            gb = {}
            gb['name'] = 'basic_{}_pcb'.format(name)
            gb['comment'] = 'PCB diff between the last two changes'
            gb['type'] = name
            gb['dir'] = 'diff'
            gb['layers'] = [Diff.layer2dict(la) for la in layers]
            gb['options'] = {'old': 'KIBOT_LAST-1', 'old_type': 'git', 'new': 'HEAD', 'new_type': 'git',
                             'cache_dir': os.path.abspath('.cache'), 'add_link_id': True}
            outs.append(gb)
        if GS.sch_file and Diff.has_repo(git_command, GS.sch_file):
            gb = {}
            gb['name'] = 'basic_{}_sch'.format(name)
            gb['comment'] = 'Schematic diff between the last two changes'
            gb['type'] = name
            gb['dir'] = 'diff'
            gb['options'] = {'old': 'KIBOT_LAST-1', 'old_type': 'git', 'new': 'HEAD', 'new_type': 'git',
                             'cache_dir': os.path.abspath('.cache'), 'add_link_id': True, 'pcb': False}
            outs.append(gb)
        return outs

    def run(self, name):
        self.options.layers = self.layers
        super().run(name)
