/*
 *  Empire - A multi-player, client/server Internet based war game.
 *  Copyright (C) 1986-2021, Dave Pare, Jeff Bailey, Thomas Ruschak,
 *                Ken Stevens, Steve McClure, Markus Armbruster
 *
 *  Empire is free software: you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation, either version 3 of the License, or
 *  (at your option) any later version.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program.  If not, see <http://www.gnu.org/licenses/>.
 *
 *  ---
 *
 *  See files README, COPYING and CREDITS in the root of the source
 *  tree for related information and legal notices.  It is expected
 *  that future projects/authors will amend these files as needed.
 *
 *  ---
 *
 *  cons.c: Consider a loan
 *
 *  Known contributors to this file:
 *     Markus Armbruster, 2004-2014
 */

#include <config.h>

#include "commands.h"
#include "loan.h"
#include "news.h"
#include "optlist.h"

struct ltcomstr {
    int type;			/* currently always EF_LOAN */
    int num;			/* number */
    char *name;			/* "loan" */
    char *Name;			/* "Loan" */
    natid proposer;		/* country offering */
    natid proposee;		/* country offered to */
    natid mailee;		/* who gets mail about it */
    char op;			/* 'a', 'd', or 'p' */
    union {
	struct lonstr l;	/* the loan */
    } u;
};

static int cons_choose(struct ltcomstr *ltcp);
static int cons_display(struct ltcomstr *ltcp);
static int cons_accept(struct ltcomstr *ltcp);
static int cons_decline(struct ltcomstr *ltcp);
static int cons_postpone(struct ltcomstr *ltcp);
static int loan_accept(struct ltcomstr *ltcp);
static int loan_decline(struct ltcomstr *ltcp);
static void accpt(struct ltcomstr *ltcp);
static void decline(struct ltcomstr *ltcp);
static void late(struct ltcomstr *ltcp);
static void prev_signed(struct ltcomstr *ltcp);

int
c_consider(void)
{
    int rv;
    struct ltcomstr ltc;

    rv = cons_choose(&ltc);
    if (rv != RET_OK)
	return rv;

    switch (ltc.op) {
    case 'a':
	return cons_accept(&ltc);
    case 'd':
	return cons_decline(&ltc);
    case 'p':
	return cons_postpone(&ltc);
    default:
	CANT_REACH();
	return RET_SYN;
    }
}

/*
 * Choose whether we want to accept, decline, or postpone a
 * loan.  Put all the goodies in ltcp, and return
 * RET_OK if all goes well, and anything else on error.
 */
static int
cons_choose(struct ltcomstr *ltcp)
{
    static int lon_or_trt[] = { EF_LOAN, EF_BAD };
    char *p;
    struct lonstr *lp;
    char prompt[128];
    char buf[1024];

    memset(ltcp, 0, sizeof(*ltcp));
    p = player->argp[1] ? player->argp[1] : "loan";
    ltcp->type = ef_byname_from(p, lon_or_trt);
    switch (ltcp->type) {
    case EF_LOAN:
	if (!opt_LOANS) {
	    pr("Loans are not enabled.\n");
	    return RET_FAIL;
	}
	ltcp->name = "loan";
	ltcp->Name = "Loan";
	break;
    default:
	pr("You must specify \"loan\".\n");
	return RET_SYN;
    }
    sprintf(prompt, "%s number? ", ltcp->Name);
    if ((ltcp->num = onearg(player->argp[2], prompt)) < 0)
	return RET_SYN;
    if (!ef_read(ltcp->type, ltcp->num, &ltcp->u) || !cons_display(ltcp)) {
	pr("%s #%d is not being offered to you!\n", ltcp->Name, ltcp->num);
	return RET_SYN;
    }
    switch (ltcp->type) {
    case EF_LOAN:
	lp = &ltcp->u.l;
	if (lp->l_status == LS_SIGNED) {
	    pr("That loan has already been accepted!\n");
	    return RET_FAIL;
	}
	ltcp->proposer = lp->l_loner;
	ltcp->proposee = lp->l_lonee;
	break;
    }
    ltcp->mailee = (ltcp->proposer == player->cnum)
	? ltcp->proposee : ltcp->proposer;
    p = getstarg(player->argp[3], "Accept, decline or postpone? ", buf);
    if (!p || (*p != 'a' && *p != 'd' && *p != 'p'))
	return RET_SYN;
    ltcp->op = *p;
    return RET_OK;
}

static int
cons_display(struct ltcomstr *ltcp)
{
    switch (ltcp->type) {
    case EF_LOAN:
	return disloan(ltcp->num, &ltcp->u.l);
    default:
	CANT_REACH();
	return 0;
    }
}

static int
cons_accept(struct ltcomstr *ltcp)
{
    switch (ltcp->type) {
    case EF_LOAN:
	return loan_accept(ltcp);
    default:
	CANT_REACH();
	return RET_FAIL;
    }
}

static int
cons_decline(struct ltcomstr *ltcp)
{
    switch (ltcp->type) {
    case EF_LOAN:
	return loan_decline(ltcp);
    default:
	CANT_REACH();
	return RET_FAIL;
    }
}

static int
cons_postpone(struct ltcomstr *ltcp)
{
    pr("%s %d is still pending.\n", ltcp->Name, ltcp->num);
    if (ltcp->proposee == player->cnum)
	wu(0, ltcp->proposer, "%s %d considered by %s\n",
	   ltcp->name, ltcp->num, cname(player->cnum));
    return RET_OK;
}

/*
 * Accept a loan.  If the offering country has too little money,
 * leave him $100 left and offer the rest.  Return RET_OK on
 * success, anything else on error.
 */
static int
loan_accept(struct ltcomstr *ltcp)
{
    struct lonstr *lp;
    struct natstr *lender;
    struct nstr_item nstr;
    struct lonstr loan;

    lp = &ltcp->u.l;
    if (ltcp->proposee != player->cnum) {
	pr("%s %d is still pending.\n", ltcp->Name, ltcp->num);
	return RET_OK;
    }
    if (!getloan(ltcp->num, lp)) {
	logerror("loan_accept: can't read loan");
	pr("can't read loan; get help!\n");
	return RET_FAIL;
    }
    if (lp->l_status == LS_FREE) {	/* other guy retratcted already */
	late(ltcp);
	return RET_OK;
    }
    if (lp->l_status == LS_SIGNED) {	/* already signed somehow */
	prev_signed(ltcp);
	return RET_OK;
    }
    /* check to see if a loan already exists */
    snxtitem_all(&nstr, EF_LOAN);
    while (nxtitem(&nstr, &loan)) {
	if (loan.l_status == LS_SIGNED && loan.l_lonee == lp->l_loner
	    && (loan.l_loner == lp->l_lonee)) {
	    pr("He already owes you money - make him repay his loan!\n");
	    return RET_OK;
	}
    }
    lender = getnatp(ltcp->proposer);
    if (lender->nat_money < lp->l_amtdue) {	/* other guy is poor */
	lp->l_amtdue = lender->nat_money - 100;
	pr("%s no longer has the funds.\n", cname(ltcp->proposer));
	if (lp->l_amtdue <= 0)
	    return RET_FAIL;
	pr("You may borrow $%d at the same terms.\n", lp->l_amtdue);
    }
    lender->nat_money -= lp->l_amtdue;
    putnat(lender);
    player->dolcost -= lp->l_amtdue;
    lp->l_amtpaid = 0;
    (void)time(&lp->l_lastpay);
    lp->l_duedate = lp->l_ldur * SECS_PER_DAY + lp->l_lastpay;
    lp->l_status = LS_SIGNED;
    if (!putloan(ltcp->num, lp)) {
	pr("Problem writing lp->to disk; get help!\n");
	return RET_FAIL;
    }
    accpt(ltcp);
    pr("You are now $%d richer (sort of).\n", lp->l_amtdue);
    return RET_OK;
}

/*
 * Decline a loan.  Return RET_OK on success, anything else on error.
 */
static int
loan_decline(struct ltcomstr *ltcp)
{
    struct lonstr *lp;

    lp = &ltcp->u.l;
    if (!getloan(ltcp->num, lp)) {
	logerror("loan_decline: can't read loan");
	pr("can't read loan; get help!\n");
	return RET_FAIL;
    }
    /* loan got accepted somehow between now and last time we checked */
    if (lp->l_status == LS_SIGNED) {
	late(ltcp);
	return RET_OK;
    }
    lp->l_status = LS_FREE;
    if (!putloan(ltcp->num, lp)) {
	logerror("loan_decline: can't write loan");
	pr("can't write loan; get help!\n");
	return RET_FAIL;
    }
    decline(ltcp);
    return RET_OK;
}

/*
 * Somebody tried to accept a loan that was retracted,
 * or to decline a loan they already signed.
 */
static void
late(struct ltcomstr *ltcp)
{
    pr("Too late; that %s %s!\n", ltcp->name,
       (ltcp->op == 'a') ? "is no longer being offered"
       : "has already been accepted");
}

/*
 * Loan was previously signed.
 */
static void
prev_signed(struct ltcomstr *ltcp)
{
    pr("%s #%d is already in effect.\n", ltcp->Name, ltcp->num);
}

/*
 * Post-processing after successful declination of loan.
 * Notify the folks involved.
 */
static void
decline(struct ltcomstr *ltcp)
{
    if (ltcp->proposee == player->cnum) {
	wu(0, ltcp->proposer, "%s %d refused by %s\n",
	   ltcp->Name, ltcp->num, cname(player->cnum));
	pr("%s %d refused.\n", ltcp->Name, ltcp->num);
    } else {
	wu(0, ltcp->proposee,
	   "%s offer %d retracted by %s\n",
	   ltcp->Name, ltcp->num, cname(player->cnum));
	pr("%s offer %d retracted.\n", ltcp->Name, ltcp->num);
    }
}

/*
 * Post-processing after successful acceptance of loan.
 * Notify the press, and the folks involved.
 * (Weird spelling is to avoid accept(2)).
 */
static void
accpt(struct ltcomstr *ltcp)
{
    switch (ltcp->type) {
    case EF_LOAN:
	nreport(ltcp->proposer, N_MAKE_LOAN, player->cnum, 1);
	break;
    default:
	CANT_REACH();
    }
    wu(0, ltcp->mailee, "%s #%d accepted by %s\n",
       ltcp->Name, ltcp->num, cname(player->cnum));
}
