from warnings import warn

from pyimzml.ontology.ontology import lookup_and_convert_cv_param, convert_xml_value, convert_term_name

XMLNS_PREFIX = "{http://psi.hupo.org/ms/mzml}"


def _deep_pretty(obj):
    if isinstance(obj, list):
        return [_deep_pretty(item) for item in obj]
    if isinstance(obj, dict):
        return {k: _deep_pretty(v) for k, v in obj.items()}
    if hasattr(obj, 'pretty'):
        return obj.pretty()
    return obj


class _ParseUtils:
    """
    Utility class for common parsing patterns and tracking created param groups so that
    their refs to other param groups can later be linked up.
    """
    def __init__(self):
        self.created_param_groups = []

    def param_group(self, node, **extra_fields):
        pg = ParamGroup(node, **extra_fields)
        self.created_param_groups.append(pg)
        return pg

    def optional_param_group(self, parent_node, xpath, **extra_fields):
        node = parent_node.find(xpath.format(XMLNS_PREFIX))
        return self.param_group(node, **extra_fields) if node is not None else None

    def param_groups_by_id(self, parent_node, xpath):
        return dict(
            (n.get('id', idx), self.param_group(n))
            for idx, n in enumerate(parent_node.findall(xpath.format(XMLNS_PREFIX)))
        )

    def param_groups_list(self, parent_node, xpath):
        return [self.param_group(n) for n in parent_node.findall(xpath.format(XMLNS_PREFIX))]

    def refs_list(self, parent_node, xpath):
        return [n.attrib.get('ref') for n in parent_node.findall(xpath.format(XMLNS_PREFIX))]


class Metadata:
    def __init__(self, root):
        """
        Parse metadata headers from an imzML file into a structured format for easy access in Python code.
        This class deliberately excludes spectra, as they account for significantly more memory use
        and parsing time, and typically should be treated separately.
        """
        pu = _ParseUtils()

        fd_node = root.find('{0}fileDescription'.format(XMLNS_PREFIX))
        self.file_description = pu.param_group(
            fd_node.find('{0}fileContent'.format(XMLNS_PREFIX)),
            source_files=pu.param_groups_by_id(fd_node, '{0}sourceFileList/{0}sourceFile'),
            contacts=pu.param_groups_list(fd_node, '{0}contact'),
        )

        self.referenceable_param_groups = pu.param_groups_by_id(
            root,
            '{0}referenceableParamGroupList/{0}referenceableParamGroup'
        )
        self.samples = pu.param_groups_by_id(root, '{0}sampleList/{0}sample')
        self.softwares = pu.param_groups_by_id(root, '{0}softwareList/{0}software')

        self.scan_settings = {}
        for node in root.findall('{0}scanSettingsList/{0}scanSettings'.format(XMLNS_PREFIX)):
            self.scan_settings[node.get('id')] = pu.param_group(
                node,
                source_file_refs=pu.refs_list(node, '{0}sourceFileRefList/{0}sourceFileRef'),
                targets=pu.param_groups_by_id(node, '{0}targetList/{0}target'),
            )

        self.instrument_configurations = {}
        for node in root.findall('{0}instrumentConfigurationList/{0}instrumentConfiguration'.format(XMLNS_PREFIX)):
            self.instrument_configurations[node.get('id')] = pu.param_group(
                node,
                components=pu.param_groups_list(node, '{0}componentList/*'),
                software_ref=next(iter(pu.refs_list(node, '{0}softwareRef')), None),
            )

        self.data_processings = {}
        for node in root.findall('{0}dataProcessingList/{0}dataProcessing'.format(XMLNS_PREFIX)):
            self.data_processings[node.get('id')] = pu.param_group(
                node,
                methods=pu.param_groups_list(node, '{0}processingMethod')
            )

        # Apply referenceable_param_groups
        for pg in pu.created_param_groups:
            pg.apply_referenceable_param_groups(self.referenceable_param_groups)

    def pretty(self):
        """
        Returns a nested dict summarizing all contained sections, intended to help human inspection.
        """
        return {
            'file_description': self.file_description.pretty(),
            'referenceable_param_groups': _deep_pretty(self.referenceable_param_groups),
            'samples': _deep_pretty(self.samples),
            'softwares': _deep_pretty(self.softwares),
            'scan_settings': _deep_pretty(self.scan_settings),
            'instrument_configurations': _deep_pretty(self.instrument_configurations),
            'data_processings': _deep_pretty(self.data_processings),
        }


class ParamGroup:
    """
        This class exposes a group of imzML parameters at two layers of abstraction:

        High-level examples:
        `param_group['MS:0000000']`
            Access a controlled vocabulary parameter by accession ID or name, or a user-defined
            parameter by name. Controlled vocabulary parameters will take priority.
            This also inherits values from referenced referenceable param groups.
        `'particle beam' in param_group`
            Check if a parameter exists by name / accession ID.
        `param_group.targets`
            Access a subelement directly by name.

        Low-level examples:
        `param_group.cv_params` - A list of all cvParams defined in this group. Includes raw values,
                                  units, and multiple items if one accession is used multiple times.
                                  Does not include values inherited from referenceable param groups.
        `param_group.user_params` - A list of all userParams.
        `param_group.attrs` - A dict of all XML attributes.
        `param_group.subelements` - A dict of all subelements.


    """
    def __init__(self, elem, **extra_data):
        """
        Parses an XML element representing a group of controlled vocabulary parameters.

        :param elem:             an XML element containing cvParam children
        :param extra_data:       extra attributes to assign to the class instance
        """
        self.param_group_refs = [
            ref.get('ref')
            for ref in elem.findall('{0}referenceableParamGroupRef'.format(XMLNS_PREFIX))
        ]
        self.type = elem.tag.replace(XMLNS_PREFIX, '')

        # Tuples of (name, accession, parsed_value, raw_value, unit_name, unit_accession)
        # These are kept in an array as the imzML spec allows multiple uses of accession numbers
        # in the same block
        self.cv_params = []
        for node in elem.findall('{0}cvParam'.format(XMLNS_PREFIX)):
            accession = node.get('accession')
            raw_name = node.get('name')
            raw_value = node.get('value')
            unit_accession = node.get('unitAccession')
            accession, name, parsed_value, unit_name = lookup_and_convert_cv_param(
                accession, raw_name, raw_value, unit_accession
            )
            self.cv_params.append(
                (name, accession, parsed_value, raw_name, raw_value, unit_name, unit_accession)
            )

        # Tuples of (name, type, parsed_value, raw_value, unit_name, unit_accession)
        self.user_params = []
        for node in elem.findall('{0}userParam'.format(XMLNS_PREFIX)):
            name = node.get('name')
            dtype = node.get('dtype')
            raw_value = node.get('value')
            parsed_value = convert_xml_value(dtype, raw_value)
            unit_accession = node.get('unitAccession')
            unit_name = convert_term_name(unit_accession)
            self.user_params.append(
                (name, dtype, parsed_value, raw_value, unit_name, unit_accession)
            )

        # Mapping of CV param name to parsed value
        self.param_by_name = {}
        self.param_by_name.update((param[0], param[2]) for param in self.user_params)
        self.param_by_name.update((param[0], param[2]) for param in self.cv_params)
        # Mapping of CV param accession to parsed value
        self.param_by_accession = {
            param[1]: param[2] for param in self.cv_params
        }

        self.attrs = elem.attrib

        self.subelements = extra_data
        for k, v in extra_data.items():
            setattr(self, k, v)

    def __getitem__(self, key):
        try:
            return self.param_by_accession[key]
        except KeyError:
            return self.param_by_name[key]

    def __contains__(self, key):
        return key in self.param_by_accession or key in self.param_by_name

    def apply_referenceable_param_groups(self, rpgs):
        for ref in self.param_group_refs[::-1]:
            rpg = rpgs.get(ref)
            if rpg:
                for name, accession, parsed_value, *_ in rpg.cv_params:
                    if name is not None and name != accession:
                        self.param_by_name.setdefault(name, parsed_value)
                    self.param_by_accession.setdefault(accession, parsed_value)
                for name, _, parsed_value, *_ in rpg.user_params:
                    self.param_by_name.setdefault(name, parsed_value)
            else:
                warn('ReferenceableParamGroup "%s" not found' % ref)

    def pretty(self):
        """
        Flattens attributes, params and extra fields into a single dict keyed by name.
        This function is intended to help human inspection. For programmatic access to specific fields,
        always use the `attrs`, `param_by_name`, `param_by_accession`, etc. instance attributes instead.
        """
        result = {
            'type': self.type,
        }
        result.update(self.attrs)
        result.update(self.param_by_name)
        result.update(_deep_pretty(self.subelements))

        return result


class SpectrumData(ParamGroup):
    def __init__(self, root, referenceable_param_groups):
        pu = _ParseUtils()

        scan_list_params = pu.optional_param_group(root, '{0}scanList')
        scans = []
        for node in root.findall('{0}scanList/{0}scan'.format(XMLNS_PREFIX)):
            scans.append(
                pu.param_group(
                    node,
                    scan_windows=pu.param_groups_list(node, '{0}scanWindowList/{0}scanWindow')
                )
            )

        precursors = []
        for node in root.findall('{0}precursorList/{0}precursor'.format(XMLNS_PREFIX)):
            precursors.append(
                pu.param_group(
                    node,
                    isolation_window=pu.optional_param_group(node, '{0}isolationWindow'),
                    selected_ions=pu.param_groups_list(node, '{0}selectedIonList/{0}selectedIon'),
                    activation=pu.optional_param_group(node, '{0}activation'),
                )
            )

        products = []
        for node in root.findall('{0}productList/{0}product'.format(XMLNS_PREFIX)):
            products.append(
                pu.param_group(
                    node,
                    isolation_window=pu.optional_param_group(node, '{0}isolationWindow'),
                )
            )

        binary_data_arrays = pu.param_groups_list(root, '{0}binaryDataArrayList/{0}binaryDataArray')

        super().__init__(
            root,
            scan_list_params=scan_list_params,
            scans=scans,
            precursors=precursors,
            products=products,
            binary_data_arrays=binary_data_arrays,
        )

        for pg in pu.created_param_groups:
            pg.apply_referenceable_param_groups(referenceable_param_groups)

        self.apply_referenceable_param_groups(referenceable_param_groups)
