drop schema if exists bank cascade;
create schema bank;
set search_path TO bank;

/************************************************************************

 ************************************************************************/
create type holder_type as enum ('BANK', 'PERSON', 'COMPANY');

create table holder (
  "id" bigint primary key generated always as identity,          
  "type" holder_type not null,
  "created_at" timestamp not null default current_timestamp
);

/************************************************************************
 * Bank
 * Liée par références à titulaire (holder) pas d'incrément automatique
 * puisque c'est celui de titulaire
 ************************************************************************/
create table bank (
  "id" bigint primary key references holder(id),
  "name" text not null
);

insert into holder (type) values ('BANK') returning holder;
insert into bank (id, name) values (1, 'Banque de l''Est');

/************************************************************************
 * Person
 * Liée par références à titulaire (holder) pas d'incrément automatique
 * on delete cascade : Lors de la suppression du titualaire, person est
 * supprimé aussi. Sans cela la suppression est interdite.
 ************************************************************************/
create table person (
  "id" bigint primary key references holder(id) on delete cascade,
  "firstname" text not null,
  "lastname" text not null,
  "birthdate" date not null check (birthdate <= current_date - interval '15 years')
);

/************************************************************************
 * Company
 * 
 ************************************************************************/
create table company (
  "id" bigint primary key references holder(id) on delete cascade,
  "name" text not null,
  "registration_number" text unique not null,
  "creation_date" date not null
);

/************************************************************************
 * Company
 * 
 ************************************************************************/
create table currency (
  "code" text primary key
);

insert into currency 
  values ('EUR'), ('YEN'), ('USD');

/************************************************************************
 * Exchange Rate
 * La clé primaire est sur les deux colonnes currency_code et date
 * Il n'y a qu'un seul taux de change par monnaie ET par jour
 ************************************************************************/
create table exchange_rate (
  "currency_code" text references currency(code) on delete cascade,
  "date" date ,
  "rate" decimal not null,
  primary key (currency_code, date)
);

insert into exchange_rate values
  ('EUR', '1999-01-04', 1),
  ('USD', '1999-01-04', 1.1789),
  ('YEN', '1999-01-04', 133.73);

create or replace function latest_exchange_rate (
  p_code text,
  p_date date
)
returns decimal
language sql
as $$
select rate 
  from exchange_rate
  where currency_code = p_code 
    and date < p_date
    order by date desc
    limit 1;
$$;

/*
 * Account
 * La contrainte check (balance >= 0) empêche les soldes négatifs
 */
create table account (
  "id" bigint primary key generated always as identity,
  "opened_at" date not null default current_date,
  "balance" numeric(18,6) not null default 0,
  "currency_code" text not null references currency (code)
);

/*
 * Account -> Holder
 * Cette table établit la relation n–n entre account et holder.
 * Un compte joint correspond donc à plusieurs lignes dans cette table.
 * La contrainte share assure que les parts sont comprises entre 0 et 1.
 */
create table account_holder (
  "account_id" int not null references account(id) on delete cascade,
  "holder_id" int not null references holder(id) on delete cascade,
  "share" decimal(4,3) not null default 1 check (share > 0 and share <= 1),
  primary key (account_id, holder_id)
);

create table transaction (
  "id" bigint primary key generated always as identity,
  "transaction_date" timestamp not null default current_timestamp,
  amount decimal not null check (amount > 0)
);

create table operation (
  "id" bigint primary key generated always as identity,
  "transaction_id" bigint not null references transaction(id),
  "account_id" bigint not null references account(id),
  amount decimal not null check (amount > 0),
  direction text not null check (direction in ('DEBIT', 'CREDIT'))
);

/************************************************************************
 * Procédures
 * Permet dans un bloc de code d'exécuter plusieurs opérations d'un seul coup
 * Si une erreur survient RIEN n'est enregistré
 ************************************************************************/
create or replace procedure add_bank (
  name text
)
language plpgsql
as $$
declare
  v_holder_id bigint;
begin

  insert into holder(type) values ('BANK')
  returning id into v_holder_id;

  insert into bank(id, name)
  values (v_holder_id, name);

  raise notice 'Titulaire créé : % = %',
    v_holder_id, name;
end;
$$;

create or replace procedure add_person (
  p_firstname text,
  p_lastname text,
  p_birthdate date
)
language plpgsql
as $$
declare
  v_holder_id bigint;
begin

  insert into holder(type) values ('PERSON')
  returning id into v_holder_id;

  insert into person(id, firstname, lastname, birthdate)
  values (v_holder_id, p_firstname, p_lastname, p_birthdate);

  raise notice 'Titulaire créé : % = % %',
    v_holder_id, p_firstname, p_lastname;
end;
$$;

call add_person('Françoise', 'Zanetti', '1995-04-12');
call add_person('Justin', 'Hébrard', '1993-03-11');

create or replace procedure add_company (
 p_name text,
 p_registration_number text,
 p_created_at date
)
language plpgsql
as $$
declare
  v_holder_id bigint;
begin

  insert into holder(type) values ('COMPANY')
  returning id into v_holder_id;

  insert into company(id, name, registration_number, created_at)
  values (v_holder_id, p_name, p_registration_number, p_created_at);

  raise notice 'Titulaire créé : % = % %',
    v_holder_id, p_name, p_registration_number;
end;
$$;

call add_company('Boulangerie de Valorgue', 'FR19803269968', '2014-08-19');

create or replace procedure add_account(
    p_currency text,
    p_holders int[],
    p_shares numeric[]
)
language plpgsql
as $$
declare
    v_account_id int;
    v_sum numeric(6,4) := 0;
    v_count int;
begin
    -- Vérification des tailles
    if array_length(p_holders, 1) is null or array_length(p_shares, 1) is null then
        raise exception 'Les tableaux de titulaires et de parts ne peuvent pas être vides.';
    end if;

    if array_length(p_holders, 1) <> array_length(p_shares, 1) then
        raise exception 'Les tableaux de titulaires et de parts doivent avoir la même taille.';
    end if;

    -- Calcul de la somme des parts
    -- select sum(unnest(p_shares)) into v_sum;
    for i in 1..array_length(p_shares, 1) loop
        v_sum := v_sum + p_shares[i];
    end loop;

    if abs(v_sum - 1.0) > 0.0001 then
        raise exception 'La somme des parts (%.4f) doit être égale à 1.0000', v_sum;
    end if;

    -- Vérification des titulaires
    select count(*) into v_count from holder where id = any(p_holders);
    if v_count <> array_length(p_holders, 1) then
        raise exception 'Un ou plusieurs titulaires n''existent pas.';
    end if;

    -- Création du compte
    insert into account(currency_code, balance)
    values (p_currency, 0)
    returning id into v_account_id;

    -- Association des titulaires
    for i in 1..array_length(p_holders, 1) loop
        insert into account_holder(account_id, holder_id, share)
        values (v_account_id, p_holders[i], p_shares[i]);
    end loop;

    raise notice 'Compte créé avec succès (ID=%) avec % titulaires.',
        v_account_id, array_length(p_holders, 1);
end;
$$;

call add_account('EUR', array[1], array[1]);
call add_account('USD', array[1], array[1]);
call add_account('YEN', array[1], array[1]);

update account set balance = 100000 where id = 1;
update account set balance = 50000 where id = 2;
update account set balance = 2000000 where id = 3;

call add_account('EUR', array[2, 3], array[0.6, 0.4]);

call add_person('Kaneda', 'Shōtarō', '1982-12-20');
call add_account('YEN', array[5], array[1]);

call add_company('Boucherie Sanzot', 'FR68487684235', '2014-08-14');
call add_account('EUR', array[6], array[1]);

call add_company('America Logistics', '95-4524149', '1996-09-24');
call add_account('EUR', array[7], array[1]);
call add_account('USD', array[7], array[1]);

create or replace view holder_detail as
select h.id, h.type, 
  case 
  when type = 'PERSON' then firstname || ' ' || lastname
  else name
  end as nom,
  case 
  when type = 'PERSON' then age(birthdate)
  when type = 'COMPANY' then age(c.created_at)
  end as age 
from holder h
  left join person p on p.id = h.id
  left join company c on c.id = h.id;

create or replace view account_detail as
select a.balance, 
  a.balance * ah.share as balance_currency,
  a.balance * ah.share / latest_exchange_rate(a.currency_code, current_date),
  a.currency_code,
  hd.nom
from account a
join account_holder ah on ah.account_id = a.id
join holder_detail hd on ah.holder_id = hd.id;


/************************************************************************
 * Transactions
 ************************************************************************/

insert into transaction (amount) values (100);

insert into operation (transaction_id, account_id, amount, direction) 
  values (1, 4, 100, 'CREDIT');

insert into operation (transaction_id, account_id, amount, direction) 
  values (1, 1, 100, 'DEBIT');

insert into transaction (amount) values (10000);

insert into operation (transaction_id, account_id, amount, direction) 
  values (2, 5, 10000, 'CREDIT');

insert into operation (transaction_id, account_id, amount, direction) 
  values (2, 3, 10000, 'DEBIT');