/**
 * \file mon-msg.c
 * \brief Monster message code.
 *
 * Copyright (c) 1997-2016 Jeff Greene, Andi Sidwell
 *
 * This work is free software; you can redistribute it and/or modify it
 * under the terms of either:
 *
 * a) the GNU General Public License as published by the Free Software
 *    Foundation, version 2, or
 *
 * b) the "Angband licence":
 *    This software may be copied and distributed for educational, research,
 *    and not for profit purposes provided that this copyright and statement
 *    are included in all such copies.  Other copyrights may also apply.
 */

#include "angband.h"
#include "mon-desc.h"
#include "mon-msg.h"
#include "mon-predicate.h"
#include "mon-util.h"
#include "game-input.h"
#include "player-calcs.h"

/**
 * Maxinum number of stacked monster messages
 */
#define MAX_STORED_MON_MSG		200
#define MAX_STORED_MON_CODES	400

/**
 * Flags for whether monsters are offscreen or invisible
 */
#define MON_MSG_FLAG_OFFSCREEN	0x01
#define MON_MSG_FLAG_INVISIBLE	0x02

/**
 * A stacked monster message entry
 */
struct monster_race_message {
	struct monster_race *race;	/* The race of the monster */
	int flags;					/* Flags */
	int msg_code;				/* The coded message */
	int count;					/* How many monsters triggered this message */
	int delay;					/* messages will be processed in this order: delay = 0, 1, 2 */
};

/**
 * A (monster, message type) pair used for duplicate checking
 */
struct monster_message_history {
	struct monster *mon;	/* The monster */
	int message_code;		/* The coded message */
};

static int size_mon_hist = 0;
static int size_mon_msg = 0;
static struct monster_race_message mon_msg[MAX_STORED_MON_MSG];
static struct monster_message_history mon_message_hist[MAX_STORED_MON_CODES];

/**
 * An array of monster messages in order of monster message type.
 *
 * Singular and plural modifiers are encoded in the same string. Example:
 * "[is|are] hurt" is expanded to "is hurt" if you request the singular form.
 * The string is expanded to "are hurt" if the plural form is requested.
 *
 * The singular and plural parts are optional. Example:
 * "rear[s] up in anger" only includes a modifier for the singular form.
 *
 * Any of these strings can start with "~", in which case we consider that
 * string as a whole message, not as a part of a larger message. This
 * is useful to display Moria-like death messages.
 */
static const struct {
	const char *msg;
	bool omit_subject;
	int type;
} msg_repository[] = {
	#define MON_MSG(x, t, o, s) { s, o, t },
	#include "list-mon-message.h"
	#undef MON_MSG
};

/**
 * Adds to the message queue a message describing a monster's reaction
 * to damage.
 */
void message_pain(struct monster *mon, int dam)
{
	int msg_code = MON_MSG_UNHARMED;

	/* Calculate damage levels */
	if (dam > 0) {
		/* Note -- subtle fix -CFT */
		long newhp = (long)(mon->hp);
		long oldhp = newhp + (long)(dam);
		long tmp = (newhp * 100L) / oldhp;
		int percentage = (int)(tmp);

		if (percentage > 95)		msg_code = MON_MSG_95;
		else if (percentage > 75)	msg_code = MON_MSG_75;
		else if (percentage > 50)	msg_code = MON_MSG_50;
		else if (percentage > 35)	msg_code = MON_MSG_35;
		else if (percentage > 20)	msg_code = MON_MSG_20;
		else if (percentage > 10)	msg_code = MON_MSG_10;
		else						msg_code = MON_MSG_0;
	}

	add_monster_message(mon, msg_code, false);
}

/**
 * Tracks which monster has had which pain message stored, so redundant
 * messages don't happen due to monster attacks hitting other monsters.
 * Returns true if the message is redundant.
 */
static bool redundant_monster_message(struct monster *mon, int msg_code)
{
	assert(mon);
	assert(msg_code >= 0);
	assert(msg_code < MON_MSG_MAX);

	for (int i = 0; i < size_mon_hist; i++) {
		/* Check for a matched monster & monster code */
		if (mon == mon_message_hist[i].mon &&
				msg_code == mon_message_hist[i].message_code) {
			return true;
		}
	}

	return false;
}

/**
 * Work out what flags a message should have from a monster
 */
static int message_flags(const struct monster *mon)
{
	int flags = 0;

	if (!panel_contains(mon->grid.y, mon->grid.x)) {
		flags |= MON_MSG_FLAG_OFFSCREEN;
	}

	if (!monster_is_obvious(mon)) {
		flags |= MON_MSG_FLAG_INVISIBLE;
	}

	return flags;
}

/**
 * Store the monster in the monster history for duplicate checking later
 */
static void store_monster(struct monster *mon, int msg_code)
{
	/* Record which monster had this message stored */
	if (size_mon_hist < MAX_STORED_MON_CODES) {
		mon_message_hist[size_mon_hist].mon = mon;
		mon_message_hist[size_mon_hist].message_code = msg_code;
		size_mon_hist++;
	}
}

/**
 * Try to stack a message on top of existing ones
 *
 * \returns true if successful, false if failed
 */
static bool stack_message(struct monster *mon, int msg_code, int flags)
{
	int i;

	for (i = 0; i < size_mon_msg; i++) {
		/* We found the race and the message code */
		if (mon_msg[i].race == mon->race &&
					mon_msg[i].flags == flags &&
					mon_msg[i].msg_code == msg_code) {
			mon_msg[i].count++;
			store_monster(mon, msg_code);
			return true;
		}
	}

	return false;
}

static int what_delay(int msg_code, int delay)
{
	if (msg_code == MON_MSG_DIE || msg_code == MON_MSG_DESTROYED) {
		return 2;
	} else {
		return delay ? 1 : 0;
	}
}

/**
 * Stack a codified message for the given monster race.
 *
 * Return true on success.
 */
bool add_monster_message(struct monster *mon, int msg_code, bool delay)
{
	assert(msg_code >= 0);
	assert(msg_code < MON_MSG_MAX);

	int flags = message_flags(mon);

	/* Try to stack the message on top of older messages if it isn't redunant */
	/* If not possible, check we have storage space for more messages and add */
	if (!redundant_monster_message(mon, msg_code) &&
			!stack_message(mon, msg_code, flags) &&
			size_mon_msg < MAX_STORED_MON_MSG) {
		mon_msg[size_mon_msg].race = mon->race;
		mon_msg[size_mon_msg].flags = flags;
		mon_msg[size_mon_msg].msg_code = msg_code;
		mon_msg[size_mon_msg].count = 1;
		mon_msg[size_mon_msg].delay = what_delay(msg_code, delay);
		size_mon_msg++;

		store_monster(mon, msg_code);

		player->upkeep->notice |= PN_MON_MESSAGE;

		return true;
	} else {
		return false;
	}
}

/**
 * Create the subject of the sentence for monster messages
 */
static void get_subject(char *buf, size_t buflen,
		struct monster_race *race,
		int count,
		bool invisible,
		bool offscreen)
{
	if (invisible) {
		if (count == 1) {
			my_strcpy(buf, "It", buflen);
		} else {
			strnfmt(buf, buflen, "%d monsters", count);
		}
	} else {
		/* Uniques, multiple monsters, or just one */
		if (rf_has(race->flags, RF_UNIQUE)) {
			my_strcpy(buf, race->name, buflen);
		} else if (count == 1) {
			strnfmt(buf, buflen, "The %s", race->name);
		} else {
			/* Get the plural of the race name */
			if (race->plural != NULL) {
				strnfmt(buf, buflen, "%d %s", count, race->plural);
			} else {
				strnfmt(buf, buflen, "%d %s", count, race->name);
				plural_aux(buf, buflen);
			}
		}
		if (rf_has(race->flags, RF_NAME_COMMA)) {
			my_strcat(buf, ",", buflen);
		}
	}

	if (offscreen)
		my_strcat(buf, " (offscreen)", buflen);

	/* Add a separator */
	my_strcat(buf, " ", buflen);
}

/* State machine constants for get_message_text() */
#define MSG_PARSE_NORMAL	0
#define MSG_PARSE_SINGLE	1
#define MSG_PARSE_PLURAL	2

/**
 * Formats a message based on the given message code and the plural flag.
 *
 * \param	pos		the position in buf to start writing the message into
 */
static void get_message_text(char *buf, size_t buflen,
		int msg_code,
		const struct monster_race *race,
		bool do_plural)
{
	assert(msg_code < MON_MSG_MAX);
	assert(race != NULL);
	assert(race->base != NULL);
	assert(race->base->pain != NULL);

	/* Find the appropriate message */
	const char *source = msg_repository[msg_code].msg;
	switch (msg_code) {
		case MON_MSG_95: source = race->base->pain->messages[0]; break;
		case MON_MSG_75: source = race->base->pain->messages[1]; break;
		case MON_MSG_50: source = race->base->pain->messages[2]; break;
		case MON_MSG_35: source = race->base->pain->messages[3]; break;
		case MON_MSG_20: source = race->base->pain->messages[4]; break;
		case MON_MSG_10: source = race->base->pain->messages[5]; break;
		case MON_MSG_0:  source = race->base->pain->messages[6]; break;
	}

	int state = MSG_PARSE_NORMAL;
	size_t maxlen = strlen(source);
	size_t pos = 0;

	/* Put the message characters in the buffer */
	/* XXX This logic should be used everywhere for pluralising strings */
	for (size_t i = 0; i < maxlen && pos < buflen - 1; i++) {
		char cur = source[i];

		/*
		 * The characters '[|]' switch parsing mode and are never output.
		 * The syntax is [singular|plural]
		 */
		if (state == MSG_PARSE_NORMAL        && cur == '[') {
			state = MSG_PARSE_SINGLE;
		} else if (state == MSG_PARSE_SINGLE && cur == '|') {
			state = MSG_PARSE_PLURAL;
		} else if (state != MSG_PARSE_NORMAL && cur == ']') {
			state = MSG_PARSE_NORMAL;
		} else if (state == MSG_PARSE_NORMAL ||
				(state == MSG_PARSE_SINGLE && do_plural == false) ||
				(state == MSG_PARSE_PLURAL && do_plural == true)) {
			/* Copy the characters according to the mode */
			buf[pos++] = cur;
		}
	}

	/* We should always return to the normal state */
	assert(state == MSG_PARSE_NORMAL);

	/* Terminate the buffer */
	buf[pos] = 0;
}

#undef MSG_PARSE_NORMAL
#undef MSG_PARSE_SINGLE
#undef MSG_PARSE_PLURAL

/**
 * Accessor function - should we skip the monster name for this message type?
 */
static bool skip_subject(int msg_code)
{
	assert(msg_code >= 0);
	assert(msg_code < MON_MSG_MAX);

	return msg_repository[msg_code].omit_subject;
}

/**
 * Return a MSG_ type for the given message code (and monster)
 */
static int get_message_type(int msg_code, const struct monster_race *race)
{
	int type = msg_repository[msg_code].type;

	if (type == MSG_KILL) {
		/* Play a special sound if the monster was unique */
		if (rf_has(race->flags, RF_UNIQUE)) {
			if (race->base == lookup_monster_base("Morgoth")) {
				type = MSG_KILL_KING;
			} else {
				type = MSG_KILL_UNIQUE;
			}
		}
	}

	return type;
}

/**
 * Show the given monster message.
 */
static void show_message(struct monster_race_message *msg)
{
	char subject[60] = "";
	char body[60];

	/* Some messages don't require a monster name */
	if (!skip_subject(msg->msg_code)) {
		/* Get 'it ' or '3 monsters (offscreen) ' or '15000 snakes ' etc */
		get_subject(subject, sizeof(subject),
				msg->race,
				msg->count,
				msg->flags & MON_MSG_FLAG_INVISIBLE,
				msg->flags & MON_MSG_FLAG_OFFSCREEN);
	}

	/* Get the message proper, corrected for singular/plural etc. */
	get_message_text(body, sizeof(body),
			msg->msg_code,
			msg->race,
			msg->count > 1);

	/* Show the message */
	msgt(get_message_type(msg->msg_code, msg->race),
			"%s%s",
			subject,
			body);
}

/**
 * Show and then cler all stacked monster messages.
 */
void show_monster_messages(void)
{
	for (int delay = 0; delay < 3; delay++) {
		for (int i = 0; i < size_mon_msg; i++) {
			struct monster_race_message *msg = &mon_msg[i];

			/* Skip irrelevant entries */
			if (msg->delay == delay) {
				show_message(msg);
			}
		}
	}

	/* Delete all the stacked messages and history */
	size_mon_msg = size_mon_hist = 0;
}
