import enum

import marshmallow
from marshmallow import INCLUDE
from marshmallow_enum import EnumField

from crc import ma
from crc.models.workflow import WorkflowStatus


class MultiInstanceType(enum.Enum):
    none = "none"
    looping = "looping"
    parallel = "parallel"
    sequential = "sequential"


class Task(object):

    ENUM_OPTIONS_FILE_PROP = "enum.options.file"
    EMUM_OPTIONS_VALUE_COL_PROP = "enum.options.value.column"
    EMUM_OPTIONS_LABEL_COL_PROP = "enum.options.label.column"
    EMUM_OPTIONS_AS_LOOKUP = "enum.options.lookup"


    def __init__(self, id, name, title, type, state, form, documentation, data,
                 mi_type, mi_count, mi_index, process_name, properties):
        self.id = id
        self.name = name
        self.title = title
        self.type = type
        self.state = state
        self.form = form
        self.documentation = documentation
        self.data = data
        self.mi_type = mi_type # Some tasks have a repeat behavior.
        self.mi_count = mi_count # This is the number of times the task could repeat.
        self.mi_index = mi_index # And the index of the currently repeating task.
        self.process_name = process_name
        self.properties = properties # Arbitrary extension properties from BPMN editor.


class OptionSchema(ma.Schema):
    class Meta:
        fields = ["id", "name"]


class ValidationSchema(ma.Schema):
    class Meta:
        fields = ["name", "config"]


class PropertiesSchema(ma.Schema):
    class Meta:
        fields = ["id", "value"]


class FormFieldSchema(ma.Schema):
    class Meta:
        fields = [
            "id", "type", "label", "default_value", "options", "validation", "properties", "value"
        ]

    default_value = marshmallow.fields.String(required=False, allow_none=True)
    options = marshmallow.fields.List(marshmallow.fields.Nested(OptionSchema))
    validation = marshmallow.fields.List(marshmallow.fields.Nested(ValidationSchema))
    properties = marshmallow.fields.List(marshmallow.fields.Nested(PropertiesSchema))


class FormSchema(ma.Schema):
    key = marshmallow.fields.String(required=True, allow_none=False)
    fields = marshmallow.fields.List(marshmallow.fields.Nested(FormFieldSchema))


class TaskSchema(ma.Schema):
    class Meta:
        fields = ["id", "name", "title", "type", "state", "form", "documentation", "data", "mi_type",
                  "mi_count", "mi_index", "process_name", "properties"]

    mi_type = EnumField(MultiInstanceType)
    documentation = marshmallow.fields.String(required=False, allow_none=True)
    form = marshmallow.fields.Nested(FormSchema, required=False, allow_none=True)
    title = marshmallow.fields.String(required=False, allow_none=True)
    properties = marshmallow.fields.List(marshmallow.fields.Nested(PropertiesSchema))
    process_name = marshmallow.fields.String(required=False, allow_none=True)

    @marshmallow.post_load
    def make_task(self, data, **kwargs):
        return Task(**data)


class WorkflowApi(object):
    def __init__(self, id, status, user_tasks, last_task, next_task, previous_task,
                 spec_version, is_latest_spec, workflow_spec_id):
        self.id = id
        self.status = status
        self.user_tasks = user_tasks
        self.last_task = last_task  # The last task that was completed, may be different than previous.
        self.next_task = next_task  # The next task that requires user input.
        self.previous_task = previous_task  # The opposite of next task.
        self.workflow_spec_id = workflow_spec_id
        self.spec_version = spec_version
        self.is_latest_spec = is_latest_spec

class WorkflowApiSchema(ma.Schema):
    class Meta:
        model = WorkflowApi
        fields = ["id", "status", "user_tasks", "last_task", "next_task", "previous_task",
                  "workflow_spec_id", "spec_version", "is_latest_spec"]
        unknown = INCLUDE

    status = EnumField(WorkflowStatus)
    user_tasks = marshmallow.fields.List(marshmallow.fields.Nested(TaskSchema, dump_only=True))
    last_task = marshmallow.fields.Nested(TaskSchema, dump_only=True)
    next_task = marshmallow.fields.Nested(TaskSchema, dump_only=True, required=False)
    previous_task = marshmallow.fields.Nested(TaskSchema, dump_only=True, required=False)

    @marshmallow.post_load
    def make_workflow(self, data, **kwargs):
        keys = ['id', 'status', 'user_tasks', 'last_task', 'next_task', 'previous_task',
                'workflow_spec_id', 'spec_version', 'is_latest_spec']
        filtered_fields = {key: data[key] for key in keys}
        return WorkflowApi(**filtered_fields)