use chrono::NaiveDateTime;
use diesel::prelude::*;
use juniper_codegen::{GraphQLInputObject, GraphQLObject};

use crate::models::{Customer, Invoice, TimeEntry};
use crate::schema::tasks;
use crate::DbConn;

/// The task (or project) model.
///
/// This model represents a task (or project) of a customer on which time can be registered.
/// generated.
#[derive(AsChangeset, Associations, Debug, GraphQLObject, Identifiable, Queryable)]
#[belongs_to(Customer)]
#[belongs_to(Invoice)]
#[table_name = "tasks"]
pub struct Task {
    /// The unique identification number
    pub id: i32,
    /// The ID of the associated customer
    pub customer_id: i32,
    /// The fixed cost of the task (if applicable)
    pub fixed_cost: Option<f64>,
    /// The hourly rate of the task (if applicable)
    pub hourly_rate: Option<f64>,
    /// An extra comment for on the invoice
    pub invoice_comment: String,
    /// The associated invoice (if billed)
    pub invoice_id: Option<i32>,
    /// The name/description
    pub name: String,
    /// The VAT rate (at time of billing)
    pub vat_rate: f64,
    /// The time of creation
    pub created_at: NaiveDateTime,
    /// The time of last update
    pub updated_at: NaiveDateTime,
}

impl Task {
    /// Returns the associated customer.
    pub fn customer(&self, conn: &DbConn) -> QueryResult<Customer> {
        use diesel::associations::HasTable;

        Customer::table().find(self.customer_id).first(&**conn)
    }

    /// Returns the associated invoice (if billed)
    pub fn invoice(&self, conn: &DbConn) -> QueryResult<Option<Invoice>> {
        use diesel::associations::HasTable;

        match self.invoice_id {
            Some(invoice_id) => Invoice::table().find(invoice_id).first(&**conn).optional(),
            None => Ok(None),
        }
    }

    /// Returns the registered time entries.
    pub fn time_entries(&self, conn: &DbConn) -> QueryResult<Vec<TimeEntry>> {
        TimeEntry::belonging_to(self).load(&**conn)
    }
}

/// The new task model.
///
/// This model represents a new task (or project) of a customer that can be inserted into the
/// database.
#[derive(Debug, GraphQLInputObject, Insertable)]
#[table_name = "tasks"]
pub struct NewTask {
    /// The ID of the associated customer
    pub customer_id: i32,
    /// The fixed cost of the task (if applicable)
    pub fixed_cost: Option<f64>,
    /// The hourly rate of the task (if applicable)
    pub hourly_rate: Option<f64>,
    /// An extra comment for on the invoice
    pub invoice_comment: String,
    /// The associated invoice (if billed)
    pub invoice_id: Option<i32>,
    /// The name/description
    pub name: String,
    /// The VAT rate (at time of billing)
    pub vat_rate: f64,
}