-- One-shot: run in Supabase Dashboard → SQL Editor **after** schemas/rpc_collect_match_entries.sql
-- Atomically settles a match: sets winner_id, pays prize + house fee only from the match escrow,
-- grants prize_cc to both participants, marks settled_at. Idempotent if already settled for same winner.

create or replace function public.settle_match_reward(p_match_id bigint, p_winner_id bigint)
returns jsonb
language plpgsql
security definer
set search_path = public
as $$
declare
  v_match public.matches%rowtype;
  v_system bigint := 1;
  v_entry_fee bigint;
  v_prize_cc bigint;
  v_bet_fee_pct integer;
  v_fee_each bigint;
  v_house_total bigint;
  v_rc_prize bigint;
  v_escrow_rc numeric;
  v_bet_fee_raw text;
begin
  if p_match_id is null or p_match_id < 1 then
    raise exception 'invalid_match';
  end if;
  if p_winner_id is null or p_winner_id < 1 then
    raise exception 'invalid_winner';
  end if;

  select * into v_match
  from public.matches
  where id = p_match_id
  for update;

  if not found then
    raise exception 'match_not_found';
  end if;

  if v_match.settled_at is not null then
    if v_match.winner_id = p_winner_id then
      return jsonb_build_object(
        'ok', true,
        'already_settled', true,
        'match_id', p_match_id,
        'winner_id', v_match.winner_id,
        'entry_fee', coalesce(v_match.entry_fee, 0),
        'rc_prize', null,
        'participant_cc', coalesce(v_match.prize_cc, 100),
        'settled_at', v_match.settled_at
      );
    end if;
    raise exception 'winner_already_set';
  end if;

  if v_match.winner_id is not null and v_match.winner_id <> p_winner_id then
    raise exception 'winner_already_set';
  end if;

  if v_match.entries_collected_at is null then
    raise exception 'entries_not_collected';
  end if;

  if v_match.escrow_user_id is null then
    raise exception 'escrow_missing';
  end if;

  if p_winner_id is distinct from v_match.user_red
     and p_winner_id is distinct from v_match.user_blue then
    raise exception 'winner_not_participant';
  end if;

  v_entry_fee := coalesce(v_match.entry_fee, 0);
  v_prize_cc := coalesce(v_match.prize_cc, 100);
  if v_prize_cc < 0 then
    v_prize_cc := 100;
  end if;

  select value into v_bet_fee_raw
  from public.settings
  where key = 'bet_fee'
  limit 1;

  begin
    v_bet_fee_pct := coalesce(nullif(trim(v_bet_fee_raw), '')::integer, 10);
  exception when others then
    v_bet_fee_pct := 10;
  end;

  if v_bet_fee_pct < 0 or v_bet_fee_pct > 100 then
    v_bet_fee_pct := 10;
  end if;

  v_fee_each := ceil((v_entry_fee::numeric * v_bet_fee_pct) / 100)::bigint;
  v_house_total := v_fee_each * 2;
  v_rc_prize := (v_entry_fee * 2) - v_house_total;

  if v_rc_prize < 0 then
    raise exception 'invalid_prize';
  end if;

  select coalesce(rc, 0) into v_escrow_rc
  from public.users
  where id = v_match.escrow_user_id
  for update;

  if not found then
    raise exception 'escrow_not_found';
  end if;

  if v_escrow_rc <> (v_entry_fee * 2) then
    raise exception 'escrow_balance_mismatch';
  end if;

  if v_rc_prize > 0 then
    update public.users
    set rc = coalesce(rc, 0) - v_rc_prize
    where id = v_match.escrow_user_id
      and coalesce(rc, 0) >= v_rc_prize;
    if not found then
      raise exception 'insufficient_escrow';
    end if;

    update public.users
    set rc = coalesce(rc, 0) + v_rc_prize
    where id = p_winner_id;
    if not found then
      raise exception 'winner_not_found';
    end if;

    insert into public.transactions ("from", "to", amount, remarks, match_id)
    values (v_match.escrow_user_id, p_winner_id, v_rc_prize, 'reward', p_match_id);
  end if;

  if v_house_total > 0 then
    update public.users
    set rc = coalesce(rc, 0) - v_house_total
    where id = v_match.escrow_user_id
      and coalesce(rc, 0) >= v_house_total;
    if not found then
      raise exception 'insufficient_escrow';
    end if;

    update public.users
    set rc = coalesce(rc, 0) + v_house_total
    where id = v_system;
    if not found then
      raise exception 'system_not_found';
    end if;

    insert into public.transactions ("from", "to", amount, remarks, match_id)
    values (v_match.escrow_user_id, v_system, v_house_total, 'bet_fee', p_match_id);
  end if;

  -- Escrow must be empty after settle.
  update public.users
  set rc = 0
  where id = v_match.escrow_user_id
    and coalesce(rc, 0) = 0;
  if not found then
    raise exception 'escrow_not_zero';
  end if;

  if v_match.user_red is not null then
    update public.users
    set cc = coalesce(cc, 0) + v_prize_cc
    where id = v_match.user_red;
  end if;
  if v_match.user_blue is not null then
    update public.users
    set cc = coalesce(cc, 0) + v_prize_cc
    where id = v_match.user_blue;
  end if;

  update public.matches
  set
    winner_id = p_winner_id,
    settled_at = now()
  where id = p_match_id
    and settled_at is null;

  if not found then
    raise exception 'settle_race';
  end if;

  return jsonb_build_object(
    'ok', true,
    'already_settled', false,
    'match_id', p_match_id,
    'winner_id', p_winner_id,
    'entry_fee', v_entry_fee,
    'rc_prize', v_rc_prize,
    'house_fee', v_house_total,
    'participant_cc', v_prize_cc,
    'settled_at', now()
  );
end;
$$;

revoke all on function public.settle_match_reward(bigint, bigint) from public;
grant execute on function public.settle_match_reward(bigint, bigint) to service_role;