'''
    TUTORIAL 2: ERROR CHECKING AND VALIDATION

    By the time you have worked through Tutorial 2 you will be able to:
        - Use the Parser to report errors enountered when reading a file
          or deserialising a string and
        - Use the Validator to check for errors related to a model's
          description as compared to the CellML2.0 specifications.

    This tutorial assumes that you can already:
    - Read and deserialise a CellML model from a file
    - Retrieve the name and id of models, components, and variables
    - Navigate through the hierarchy of the model (model contains
      component(s) contain(s) variable(s) and maths) and
    - Serialise and print a Model structure to a CellML file.
'''

from libcellml import CellmlElementType, Issue, Parser, Printer, Validator

from utilities import print_model, get_cellml_element_type_from_enum

if __name__ == '__main__':

    print('-----------------------------------------------')
    print('   TUTORIAL 2: ERROR CHECKING AND VALIDATION   ')
    print('-----------------------------------------------')

    # ---------------------------------------------------------------------------
    #  STEP 1:   Create a CellML Model from the contents of a CellML file
    #
    print('-----------------------------------------------')
    print('   STEP 1: Parse a file into a model           ')
    print('-----------------------------------------------')

    #  1.a
    #      Read the contents of the tutorial2.cellml file into a string.

    #  1.b
    #      Create a Parser instance, and submit your string for serialisation
    #      into a new model.
    
    #  1.c
    #      Use the print_model utility function to display the contents of the 
    #      parsed model in the terminal.

    print('-----------------------------------------------')
    print('   STEP 2: Validate the model                  ')
    print('-----------------------------------------------')

    #  2.a
    #      Create a Validator and pass the model into it.

    #  2.b   
    #      Check the number of issues returned from the validator.

    #  2.c  
    #      Retrieve the issues, and print their description, url, reference, and
    #      type of item stored to the terminal.  The type of stored item is
    #      available as an enum, which can be turned into a string for output using
    #      the utility function, getItemTypeFromEnum(type).

    print('-----------------------------------------------')
    print('   STEP 3: Fix the issues reported             ')
    print('-----------------------------------------------')

    #  Validator issue[0]:
    #      Description: Variable '1st' in component 'i_am_a_component' does not have a valid name attribute. CellML identifiers must not begin with a European numeric character [0-9].
    #      Type of item stored: VARIABLE
    #      URL: https:#cellml-specification.readthedocs.io/en/latest/reference/formal_and_informative/specB08.html?issue=2.8.1.1
    #      See section 2.8.1.1 in the CellML specification.
    #  3.a
    #      Retrieve the variable named '1st' from the component named 'i_am_a_component' and change its name
    #      to 'a'.
   

    #  Validator issue[1]:
    #      Description: Variable 'b' in component 'i_am_a_component' does not have any units specified.
    #      Type of item stored: VARIABLE
    #      URL: https:#cellml-specification.readthedocs.io/en/latest/reference/formal_and_informative/specB08.html?issue=2.8.1.2
    #      See section 2.8.1.2 in the CellML specification.
    #  3.b
    #      Retrieve the variable directly from the issue using the Issue.variable() function to return it.
    #      Note that we can only do this because we know that the item type stored is a VARIABLE.
    #      Set its units to be 'dimensionless'.


    #  Validator issue[2]:
    #     Description: Variable 'c' in component 'i_am_a_component' has an invalid initial value 'this_variable_doesnt_exist'. Initial values must be a real number string or a variable reference.
    #     Type of item stored: VARIABLE
    #     URL: https:#cellml-specification.readthedocs.io/en/latest/reference/formal_and_informative/specB08.html?issue=2.8.2.2
    #     See section 2.8.2.2 in the CellML specification.
    #
    #  For this step we're going to pretend that we don't know the item type stored with the issue.
    #  We can retrieve its item using the item() function, which will return a std.any item.  We
    #  can retrieve its type using the cellmlElementType() function to return the CellmlElementType enum,
    #  and then cast the item accordinly.
    #  3.c
    #      Use the item() function to retrieve a std.any cast of the item from the third issue.  
    #      Use the cellmlElementType() to check that its type is a VARIABLE, and then cast
    #      into a VariablePtr using std.any_cast so that you can use it as normal.
    #      Set its initial value to 20.


    #  Validator issue[3]:
    #      Description: Variable 'd' in component 'i_am_a_component' has a units reference 'i_dont_exist' which is neither standard nor defined in the parent model.
    #      Type of item stored: VARIABLE
    #      URL: https:#cellml-specification.readthedocs.io/en/latest/reference/formal_and_informative/specB08.html?issue=2.8.1.2
    #      See section 2.8.1.2 in the CellML specification.
    #
    #      This error is similar in implication to that in 3.b: the validator is reporting that it can't find
    #      the Units item specified by a Variable.  It could be fixed in two different ways:
    #      - by supplying a Units item called 'i_dont_exist' or
    #      - by changing the name of the units which the variable requires to one that is available.
    #  3.d
    #      Change the name of the units required by variable 'd' to be those which are called 'i_am_a_units_item'.
    #      You will need to retrieve these units from the model in order to pass them to the variable.

    #  This issue was actually also caught by the Parser, which, like the Validator, is a Logger class.
    #  This means that it will keep track of anything it encounters when parsing a model.  You can try calling
    #  Parser.issueCount() etc and iterating through them (just like in 2.c) to see what you find.

    #  Validator issue[4]:
    #      Description: MathML ci element has the child text 'a' which does not correspond with any variable names present in component 'i_am_a_component'.
    #      Type of item stored: MATH
    #      URL: https:#cellml-specification.readthedocs.io/en/latest/reference/formal_and_informative/specB12.html?issue=2.12.3
    #      See section 2.12.3 in the CellML specification.
    #
    #  This issue is already resolved by fixing the name of the variable in step 3.a.  

    print('-----------------------------------------------')
    print('  STEP 4: Check and output the corrected model ')
    print('-----------------------------------------------')

    #  4.a
    #      Validate the corrected model again and check that there are no more issues.

    #  4.b
    #      Print the corrected model to the terminal.

    #  4.c
    #      Print corrected model to a file.

    #  4.d
    #      Go and have a cuppa, you're done!