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# Source code for samsifter.util.validation

    # -*- coding: utf-8 -*-
    """Validation of workflows.

    .. moduleauthor:: Florian Aldehoff <faldehoff@student.uni-tuebingen.de>
    """

    import os
    from os.path import isfile, dirname, exists

    """ Qt4 """
    from PyQt4.QtCore import QObject

    """ custom libraries """
    from samsifter.models.parameter import FilterFilepath

    class WorkflowValidator(QObject):
        """Validator for SamSifter workflows.

        Starts off with empty error lists for input, model and output that can
        be retrieved individually after running ``validate()``. The individual
        steps of validation should always be run in the same order.

        Lists of error messages can be retrieved individually for each of the three
        validation steps

        * input validation
        * filter model validation
        * output validation

        by calling the corresponding getter methods. They will be reported as one
        concatenated list when running the full validation.
        """

        def __init__(self, workflow, parent=None):
            """Initializes a new instance of workflow validator.

            Parameters
            ----------
            workflow : Workflow
                Workflow to be validated.
            parent : QObject
                Parent Qt object, defaults to None.
            """
            super(WorkflowValidator, self).__init__(parent)
            self.workflow = workflow
            self.input_errors = []
            self.model_errors = []
            self.output_errors = []

        def validate(self):
            """Validate input, workflow model and output in this order.

            Returns
            -------
            list of str
                List of error messages occuring in input, model and output
                validation.
            """
            # checks have to occur in this order to make sense of stream parameters
            self.validate_input()
            self.validate_model()
            self.validate_output()

            # only an error-free workflow is considered valid
            errors = self.input_errors + self.model_errors + self.output_errors
            self.workflow.set_valid(len(errors) == 0)

            # send signal about validity changes
            self.workflow.validity_changed.emit("\n".join(errors))

            return errors

        def validate_output(self):
            """Validate output file of workflow."""
            self.output_errors = []

            # assuming output as expected by MEGAN and SAM2RMA
            out_format = 'SAM'
            out_sorting = 'queryname'
            out_compr = 'any'

            outfile = self.workflow.get_out_filename()
            if outfile is None:
                self.output_errors.append("output: no filename given")
            else:
                outdir = dirname(outfile)
                if not (exists(outdir) and os.access(outdir, os.W_OK)):
                    self.output_errors.append(
                        "output: directory missing or not writable"
                    )
                if outfile.endswith(('.sam', '.SAM')):
                    out_format = 'SAM'
                    out_compr = 'uncompressed'
                elif outfile.endswith(('.sam.gz', '.SAM.GZ')):
                    out_format = 'SAM'
                    out_compr = 'gzip'
                elif outfile.endswith(('.bam', '.BAM')):
                    out_format = 'BAM'
                    out_compr = 'uncompressed'
                else:
                    out_format = 'as_input'
                    out_compr = 'as_input'
                    out_sorting = 'as_input'

            # check compatibility with post-processing and MEGAN
            if self.stream_format != out_format:
                self.output_errors.append(
                    "output: expecting %s format but receiving %s format"
                    % (out_format, self.stream_format)
                )
            if self.stream_sorting != out_sorting:
                self.output_errors.append(
                    "output: expecting %s sorting but receiving %s sorting"
                    % (out_sorting, self.stream_sorting)
                )
            if self.stream_compr != out_compr:
                self.output_errors.append(
                    "output: expecting %s format but receiving %s format"
                    % (out_compr, self.stream_compr)
                )

            # only an error-free output file is considered valid
            self.workflow.set_outfile_valid(len(self.output_errors) == 0)

        def validate_input(self):
            """Validate input file of workflow."""
            self.input_errors = []

            # assuming normal input as produced by MALT default settings
            input_format = 'SAM'
            input_sorting = 'queryname'
            input_compr = 'gzip'

            # stream starts off identical to input but may change with each step
            self.stream_format = input_format
            self.stream_sorting = input_sorting
            self.stream_compr = input_compr

            infile = self.workflow.get_in_filename()
            if infile is None:
                self.input_errors.append("input: no filename given")
                self.workflow.set_infile_valid(False)
            else:
                if not (isfile(infile) and os.access(infile, os.R_OK)):
                    self.input_errors.append("input: file missing or not readable")
                    self.workflow.set_infile_valid(False)
                if infile.endswith(('.sam', '.SAM')):
                    self.stream_format = 'SAM'
                    self.stream_compr = 'uncompressed'
                    self.workflow.set_infile_valid(True)
                elif infile.endswith(('.sam.gz', '.SAM.GZ')):
                    self.stream_format = 'SAM'
                    self.stream_compr = 'gzip'
                    self.workflow.set_infile_valid(True)
                elif infile.endswith(('.bam', '.BAM')):
                    self.stream_format = 'BAM'
                    self.stream_compr = 'uncompressed'
                    self.workflow.set_infile_valid(True)
                else:
                    self.input_errors.append("input: unsupported file format")
                    self.workflow.set_infile_valid(False)
                    self.stream_format = 'any'
                    self.stream_compr = 'any'
                    self.stream_sorting = 'any'

            # only an error-free input file is considered valid
            self.workflow.set_infile_valid(len(self.input_errors) == 0)

        def validate_model(self):
            """Validate workflow model."""
            self.model_errors = []

            # validate model
            model = self.workflow.getModel()
            for idx, item in enumerate(model.iterate_items(), 1):
                item.set_valid(True)
                exp_format = item.get_input_format()
                exp_sorting = item.get_input_sorting()
                exp_compr = item.get_input_compression()
                if self.stream_format != exp_format and exp_format != 'any':
                    self.model_errors.append(
                        "step %i: expecting %s format but receiving %s format"
                        % (idx, exp_format, self.stream_format)
                    )
                    item.set_valid(False)
                if self.stream_sorting != exp_sorting and exp_sorting != 'any':
                    self.model_errors.append(
                        "step %i: expecting %s sorting but receiving %s sorting"
                        % (idx, exp_sorting, self.stream_sorting)
                    )
                    item.set_valid(False)
                if self.stream_compr != exp_compr and exp_compr != 'any':
                    self.model_errors.append(
                        "step %i: expecting %s format but receiving %s format"
                        % (idx, exp_compr, self.stream_compr)
                    )
                    item.set_valid(False)

                # validate parameters
                for param in item.get_parameters():
                    if (
                        isinstance(param, FilterFilepath)
                        and param.is_required()
                        and not (
                            isfile(param.get_value())
                            and os.access(param.get_value(), os.R_OK)
                        )
                    ):
                        self.model_errors.append(
                            "step %i: required parameter %s either not existing "
                            "or not readable" % (idx, param)
                        )
                        item.set_valid(False)

                if item.get_output_format() != 'as_input':
                    self.stream_format = item.get_output_format()
                if item.get_output_sorting() != 'as_input':
                    self.stream_sorting = item.get_output_sorting()
                if item.get_output_compression() != 'as_input':
                    self.stream_compr = item.get_output_compression()

            # initiate repaint of view to reflect validity changes in model
            model.dataChanged.emit(model.index(1), model.index(model.rowCount()))

        """ Getters & Setters """

        def get_input_errors(self):
            return "\n".join(self.input_errors)

        def get_output_errors(self):
            return "\n".join(self.output_errors)

        def get_model_errors(self):
            return "\n".join(self.model_errors)

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