import { Project } from "../models/project";
import { Task, TaskID, EstimationConfidence } from "../models/task";

export interface Action {
    type: string
}

export type ProjectReducerActions =
    AddTaskAction |
    RemoveTaskAction |
    UpdateTaskEstimation

export function projectReducer(project: Project, action: ProjectReducerActions): Project {
    switch(action.type) {
        case ADD_TASK:
            const task = { ...(action as AddTaskAction).task };
            return {
                ...project,
                tasks: {
                    ...project.tasks,
                    [task.id]: task,
                }
            };
        case REMOVE_TASK:
            action = action as RemoveTaskAction;
            const tasks = { ...project.tasks };
            delete tasks[action.id];
            return {
                ...project,
                tasks
            };
        case UPDATE_TASK_ESTIMATION:
            action = action as UpdateTaskEstimation;
            const estimations = {
                ...project.tasks[action.id].estimations,
                [(action as UpdateTaskEstimation).confidence]: (action as UpdateTaskEstimation).value
            };
            if (estimations.likely <= estimations.optimistic) {
                estimations.likely = estimations.optimistic + 1;
            }
            if (estimations.pessimistic <= estimations.likely) {
                estimations.pessimistic = estimations.likely + 1;
            }
            return {
                ...project,
                tasks: {
                    ...project.tasks,
                    [action.id]: {
                        ...project.tasks[action.id],
                        estimations: estimations,
                    }
                }
            };
    }

    return project;
}

export interface AddTaskAction extends Action {
    task: Task
}

export const ADD_TASK = "ADD_TASK";

export function addTask(task: Task): AddTaskAction {
    return { type: ADD_TASK, task };
}

export interface RemoveTaskAction extends Action {
    id: TaskID
}

export const REMOVE_TASK = "REMOVE_TASK";

export function removeTask(id: TaskID): RemoveTaskAction {
    return { type: REMOVE_TASK, id };
}

export interface UpdateTaskEstimation extends Action {
    id: TaskID
    confidence: string
    value: number
}

export const UPDATE_TASK_ESTIMATION = "UPDATE_TASK_ESTIMATION";

export function updateTaskEstimation(id: TaskID, confidence: EstimationConfidence, value: number): UpdateTaskEstimation {
    return { type: UPDATE_TASK_ESTIMATION, id, confidence, value };
}