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

use crate::models::{CompanyInfo, Customer, Task};
use crate::schema::invoices;
use crate::DbConn;

/// The invoice model.
///
/// This model represents an invoice for a customer that contains billed tasks and through the
/// tasks the registered time.
#[derive(AsChangeset, Associations, Debug, GraphQLObject, Identifiable, Queryable)]
#[belongs_to(CompanyInfo)]
#[belongs_to(Customer)]
#[table_name = "invoices"]
pub struct Invoice {
    /// The unique identification number
    pub id: i32,
    /// The ID of the company info at the time of billing
    pub company_info_id: i32,
    /// The ID of associated customer
    pub customer_id: i32,
    /// Flag whether the invoice should include a time specification
    pub include_specification: bool,
    /// The invoice number
    pub number: i32,
    /// Flag whether the invoice has been paid
    pub paid: bool,
    /// The time of creation
    pub created_at: NaiveDateTime,
    /// The time of last update
    pub updated_at: NaiveDateTime,
}

impl Invoice {
    /// Returns the associated company info at the time of billing.
    pub fn company_info(&self, conn: &DbConn) -> QueryResult<CompanyInfo> {
        use diesel::associations::HasTable;

        CompanyInfo::table()
            .find(self.company_info_id)
            .first(&**conn)
    }

    /// 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 billed tasks included in the invoice.
    pub fn tasks(&self, conn: &DbConn) -> QueryResult<Vec<Task>> {
        Task::belonging_to(self).load(&**conn)
    }
}

/// The new invoice model.
///
/// This model represents an new invoice for a customer that can be inserted into the database.
#[derive(Debug, GraphQLInputObject, Insertable)]
#[table_name = "invoices"]
pub struct NewInvoice {
    /// The ID of the company info at the time of billing
    pub company_info_id: i32,
    /// The ID of associated customer
    pub customer_id: i32,
    /// Flag whether the invoice should include a time specification
    pub include_specification: bool,
    /// The invoice number
    pub number: i32,
    /// Flag whether the invoice has been paid
    pub paid: bool,
}