from datetime import date
from typing import List, Iterator, Optional

from services.exporter import ExportItem, CSVExporter
from constants.project_statuses import PROJECT_STATUSES_MAPPING
from projects.services.projects_service import ProjectsService
from projects.schemas import ProjectListQueryParams
from models.artists import Artist
from models.projects import ProjectEntityType


class ProjectsExporter:
    def __init__(self, service: ProjectsService = ProjectsService()):
        self.service = service

    def export_projects_csv(
        self, user_id: int, filters: ProjectListQueryParams, artist_external_id: Optional[str] = None
    ) -> str:
        """Export list of projects to CSV.

        Args:
            user_id (id): Resulting list will contain only projects available to this user. A project is available to
                a user if the user is a member of project's label or if project is shared with this user.
            filters (dict): Dictionary with optional filters. Accepts the same set of filters as get_project_list()

        Returns:
            str: Content of a CSV file as string.

        """
        # This implementation fetches all projects in a single query. It is the simplest and optimal solution while
        # there aren't many projects. When their number grows more than ten thousands a testing on real data
        # can be done to determine what kind of optimization is needed if any.
        exporter = CSVExporter()
        projects = self.service.get_project_export_list(user_id, filters, artist_external_id)
        for c in projects:
            export_item = ExportItem()
            start_date = date.strftime(c.earliest_start_date, "%Y-%m-%d") if c.earliest_start_date else ""
            end_date = date.strftime(c.latest_end_date, "%Y-%m-%d") if c.latest_end_date else ""
            export_item.add_item("Project Name", 100, c.name)
            export_item.add_item("Project Status", 200, PROJECT_STATUSES_MAPPING[c.status])
            export_item.add_item("Project Start Date", 300, start_date)
            export_item.add_item("Project End Date", 400, end_date)
            export_item.add_item("Project Budget", 500, c.planned_budget)
            export_item.add_item("Project Budget Spent", 600, c.total_spend)
            if isinstance(c.targets[0].entity, Artist):
                for i, item in enumerate(self.filter_by_type(c.targets, ProjectEntityType.PRIMARY_ARTIST)):
                    export_item.add_item(f"Primary Artist {i+1}", 700 + i, item.entity.name)
                names = ", ".join(
                    [item.entity.name for item in self.filter_by_type(c.targets, ProjectEntityType.FEATURED_ARTIST)]
                )
                if names:
                    export_item.add_item("Featured Artists", 750, names)
            else:
                names = ", ".join([item.entity.name for item in c.targets])
                export_item.add_item("Playlists", 700, names)

            exporter.add_export_item(export_item)

        return exporter.export()

    def filter_by_type(self, targets: List[Artist], entity_type: ProjectEntityType) -> Iterator[Artist]:
        return filter(lambda x: entity_type == ProjectEntityType(x.entity_type), targets)