- [+] bug: mammoan warrior with spear not agile enough to use starting

weapon!
- [+] new option when chatting:
    - [+] "care to trade knowledge?"
        - [+] works if:
            - [+] you have a skill which they don't know (or a spell
                  which they don't know)
                - [+] otherwise "there is nothing you can teach me."
            - [+] AND ONE OF
            - [+] works if they know a spell which you don't know (but
                  are able to learn)
            - [+] works if they have the same skills as you, but better,
            - [+] works if they have the a skill which you don't, AND
                  they are >= adept
                - [+] otherwise "i fear there is nothing useful i can
                      teach you"
        - [+] TEST
        - [+] can only do this once per person ("i have nothign more i
              can teach you")
        - [+] if high speech, you can pick what to learn. otherwise
              it's random.
        - [+] bug: human rogue asking to learn 'summon weapon' but not
              skilled in summoning!!!
        - [+] TEST AGAIN!
- [+] speech skill determines what you can ask people about!
    - [+] nov:any dangers?
    - [+] beg:any useful items around?
    - [+] ad:trade knowledge? 
    - [+] sk:join me?
    - [+] (but make skillchecks harder otherwise by the time you get
          the rigth speech skill level, you'll always pass!)

data.c

@@ -11549,12 +11549,12 @@ void initskills(void) {
 		addskilldesc(SK_SHIELDS, PR_EXPERT, "^gShield accuracy penalties are reduced by 5.^n", B_FALSE);
 		addskilldesc(SK_SHIELDS, PR_MASTER, "^gShield accuracy penalties are reduced by 6.^n", B_FALSE);
 	addskill(SK_SPEECH, "Negotiation", "Your skill at haggling prices, or swaying others through speech.", 50);
-		addskilldesc(SK_SPEECH, PR_NOVICE, "^gShop item prices are reduced by 5%.^n", B_FALSE);
+		addskilldesc(SK_SPEECH, PR_INEPT, "- Each skill level reduces shop prices by 5%.", B_TRUE);
-		addskilldesc(SK_SPEECH, PR_BEGINNER, "^gShop item prices are reduced by 10%.^n", B_FALSE);
+		addskilldesc(SK_SPEECH, PR_NOVICE, "^gYou can now question people about items on the current level.", B_TRUE);
-		addskilldesc(SK_SPEECH, PR_ADEPT, "^gShop item prices are reduced by 15%.^n", B_FALSE);
+		addskilldesc(SK_SPEECH, PR_BEGINNER, "^gYou can now question people about nearby traps or monsters.", B_TRUE);
-		addskilldesc(SK_SPEECH, PR_SKILLED, "^gShop item prices are reduced by 20%.^n", B_FALSE);
+		addskilldesc(SK_SPEECH, PR_ADEPT, "^gYou can now trade knowledge and spells with other people.", B_TRUE);
-		addskilldesc(SK_SPEECH, PR_EXPERT, "^gShop item prices are reduced by 25%.^n", B_FALSE);
+		addskilldesc(SK_SPEECH, PR_SKILLED, "^gYou can now persuade people to join to as followers.", B_TRUE);
-		addskilldesc(SK_SPEECH, PR_MASTER, "^gShop item prices are reduced by 30%.^n", B_FALSE);
+		addskilldesc(SK_SPEECH, PR_EXPERT, "^gYou can now choose which skills to learn from people.", B_TRUE);
 	addskill(SK_PERCEPTION, "Perception", "Your ability to notice hidden details, from simple footprints to sinister traps.", 50);
 		addskilldesc(SK_PERCEPTION, PR_INEPT, "- At higher levels this skill will also let you obscure your own tracks.", B_TRUE);
 		addskilldesc(SK_PERCEPTION, PR_NOVICE, "^gYou can now see footprints.^n", B_TRUE);

defs.h

@@ -281,6 +281,11 @@ enum RELATIVEDIR {
 	RD_SIDEWAYS,
 };
 
+enum TRADEINFOTYPE {
+	TI_SKILL,
+	TI_SPELL,
+};
+
 ///////////////////////////////////////
 //   STRINGS
 ///////////////////////////////////////
@@ -482,6 +487,11 @@ enum SAYPHRASE {
 	SP_RECRUIT_DECLINE_WONTPAY,
 	SP_SORRY,
 	SP_THANKS,
+	SP_TRADEINFO_ACCEPT,
+	SP_TRADEINFO_CANCEL,
+	SP_TRADEINFO_DECLINE_ALREADYDONE,
+	SP_TRADEINFO_DECLINE_OTHERBAD,
+	SP_TRADEINFO_DECLINE_PLAYERBAD,
 };
 
 enum SPEECHVOL {
@@ -2437,6 +2447,8 @@ enum FLAG {
 	F_DONEDARKMSG, // tells the game not to say 'it is very dark here' 
 	F_DONELISTEN, // supress further 'you hear xx' messages this turn.
 	// lifeform flags / lf flags / monster flags
+	F_DONEKNOWLEDGETRADE, // you've already traded knowledge with this
+				// person.
 	F_FOLLOWTIME, // v0 = how long will ai chase you for? defaults to
 			// DEF_AIFOLLOWTIME.
 	F_BEHAVIOUR, // textual field describing special behaviour for this

io.c

@@ -3725,17 +3725,25 @@ void docomms(lifeform_t *lf) {
 	} else if (ishirable(lf) ) {
 		if (lfhasflag(lf, F_ISPRISONER)) {
 			addchoice(&prompt, 'j', "Join me, and I will help you escape.", NULL, NULL, NULL);
-		} else {
+		} else if (getskill(player, SK_SPEECH) >= PR_SKILLED)  {
 			addchoice(&prompt, 'j', "Join me on my quest!", NULL, NULL, NULL);
 		}
 	} 
 
-	// TODO: allow you to ask this of allies, but only on the level they started on.
+	if (!isgod(lf) && ispeaceful(lf) && cantalk(lf)) {
-	if (!areallies(player, lf) && !isgod(lf)) {
+		enum SKILLLEVEL slev;
-		if (ispeaceful(lf) && cantalk(lf)) {
+		slev = getskill(player, SK_SPEECH);
+		if (slev >= PR_NOVICE) {
 			addchoice(&prompt, 'i', "What can you tell me about this area?", NULL, NULL, NULL);
+		}
+		if (slev >= PR_BEGINNER) {
 			addchoice(&prompt, 'x', "Any dangers nearby that I should look out for?", NULL, NULL, NULL);
 		}
+		if (!areallies(player, lf)) {
+			if (slev >= PR_ADEPT) {
+				addchoice(&prompt, 'k', "Care to trade knowledge?", NULL, NULL, NULL);
+			}
+		}
 	}
 
 	if (areenemies(player, lf)) {
@@ -3973,7 +3981,7 @@ void docomms(lifeform_t *lf) {
 			break;
 		case 'i':
 			msg("You say \"What can you tell me about this area?\" to %s.", lfname);
-			if (askforinfo(lf)) {
+			if (askforinfo(lf, 2)) {
 				genareaknowledge(lf->flags, 0);
 				docomms_areainfo(lfname, lf->flags, lf);
 			}
@@ -3987,6 +3995,10 @@ void docomms(lifeform_t *lf) {
 			}
 			recruit(lf);
 			break;
+		case 'k': // trade Knowledge
+			msg("You say \"Care to trade knowledge?\" to %s.", lfname);
+			tradeknowledge(lf);
+			break;
 		case 'm': // mercy
 			msg("You say \"Have mercy!\" to %s.", lfname);
 			if (islowhp(player) && 
@@ -4104,7 +4116,7 @@ void docomms(lifeform_t *lf) {
 			break;
 		case 'x':
 			msg("You say \"Any dangers nearby that I should look out for?\" to %s.", lfname);
-			if (askforinfo(lf)) {
+			if (askforinfo(lf, 4)) {
 				genareaknowledge(lf->flags, 0);
 				docomms_areadangers(lfname, lf->flags, lf);
 			}

lf.c

@@ -8264,6 +8264,93 @@ char *getskilllevelname(enum SKILLLEVEL sl) {
 }
 
 
+// get a list of of skills which teacher could teach student.
+// returns # of potential skills found.
+int getteachableskills(lifeform_t *teacher, lifeform_t *student, int *info, enum TRADEINFOTYPE *tradetype, int *ninfo ) {
+        flag_t *retflag[MAXCANDIDATES], *f;
+        int nretflags, i;
+
+	*ninfo = 0;
+	// 'teacher' can teach a skill to 'student' if:
+	//    - teacher and student both know the skill, and teacher's skill level is higher.
+	//		OR
+	//    - only teacher has the skill, and teacher's skill level is >= adept.
+	getflags(teacher->flags, retflag, &nretflags, F_HASSKILL, F_NONE);
+	for (i = 0; i < nretflags; i++) {
+		enum SKILLLEVEL studentlev,teacherlev;
+		enum SKILL sid;
+		int teachable = B_FALSE;
+		f = retflag[i];
+		sid = f->val[0];
+		teacherlev = f->val[1];
+		studentlev = getskill(student, sid);
+		if (studentlev && (teacherlev > studentlev) && !ismaxedskill(student, sid)) {
+			teachable = B_TRUE;
+		} else if (!studentlev && (teacherlev >= PR_ADEPT)) {
+			teachable = B_TRUE;
+		}
+		if (teachable) {
+			info[*ninfo] = sid;
+			tradetype[*ninfo] = TI_SKILL;
+			(*ninfo)++;	
+		}
+	}
+
+	// 'teacher' can teach a magic spell (oc_spell) to 'student' if:
+	//    - teacher can will/cast the spell.
+	//		AND
+	//    - student can't already will/cast the spell
+	//		AND
+	//    - student is skilled in at least one of the spell's schools.
+	//		AND
+	//    - student is a high enough level to cast the spell.
+	//		(use existing code from spellbooks!)
+	getflags(teacher->flags, retflag, &nretflags, F_CANCAST, F_CANWILL, F_NONE);
+	for (i = 0; i < nretflags; i++) {
+		objecttype_t *spell;
+		enum OBTYPE spellid;
+		enum SPELLSCHOOL knownschool;
+		int teachable = B_FALSE;
+		f = retflag[i];
+		spellid = f->val[0];
+		spell = findot(spellid);
+		if (spell->obclass->id != OC_SPELL) continue;
+
+		// student skilled in one of the spell's schools?
+		knownschool = getspellschoolknown(student, spellid);
+		if (getskill(student, getschoolskill(knownschool))) {
+			int mpneeded;
+			if (!cancast(student, spellid, &mpneeded) && (getspellpower(student, spellid) > 0)) {
+				if (getmaxmp(student) >= mpneeded) {
+					teachable = B_TRUE;
+				}
+			}
+		}
+
+		if (teachable) {
+			info[*ninfo] = spellid;
+			tradetype[*ninfo] = TI_SPELL;
+			(*ninfo)++;	
+		}
+	}
+	return *ninfo;
+}
+
+char *gettradeinfoname(int what, enum TRADEINFOTYPE tradetype, char *buf) {
+	if (tradetype == TI_SKILL) {
+		skill_t *sk;
+		sk = findskill(what);
+		strcpy(buf, sk->name);
+	} else { // ie. spell
+		objecttype_t *ot;
+		ot = findot(what);
+		sprintf(buf, "the spell '%s'", ot->name);
+	}
+	return buf;
+}
+
+
+
 // get throw speed (ie. damage multiplier)
 // based on strength.
 //
@@ -11801,7 +11888,7 @@ int armourfits(lifeform_t *lf, object_t *o, enum ERROR *reason) {
 }
 
 // returns TRUE if 'lf' agrees to share knowledge with the player
-int askforinfo(lifeform_t *lf) {
+int askforinfo(lifeform_t *lf, int diffmod) {
 	if (lfhasflag(lf, F_NOINFO)) {
 		// refusing to give info
 		sayphrase(lf, SP_INFO_REFUSE_AGAIN, SV_TALK, NA, NULL);
@@ -11826,7 +11913,7 @@ int askforinfo(lifeform_t *lf) {
 				int result;
 				int difficulty;
 
-				difficulty = 20 + ((gethitdice(player) - gethitdice(lf))*2);
+				difficulty = 20 + diffmod + ((gethitdice(player) - gethitdice(lf))*2);
 				if (real_skillcheck(player, SC_SPEECH, difficulty, 0, &result)) {
 					askingprice = 0;
 					// passed - free!
@@ -11962,7 +12049,8 @@ void autoskill(lifeform_t *lf) {
 	}
 
 	for (o = lf->pack->first ; o ; o = o->next) {
-		if (isweapon(o) && canweild(lf, o)) {
+		//if (isweapon(o) && canweild(lf, o)) {
+		if (isweapon(o)) {
 			sk = getobskill(o);
 			if (sk && !getskill(lf, sk->id)) {
 				giveskilllev(lf, sk->id, slev);
@@ -11970,7 +12058,7 @@ void autoskill(lifeform_t *lf) {
 			
 			// monsters:increase stats to match attribn requirements for starting
 			// weapon.
-			if (!isplayer(lf)) {
+			//if (!isplayer(lf)) {
 				getflags(o->flags, retflag, &nretflags, F_ATTREQ, F_NONE);
 				for (i = 0; i < nretflags; i++) {
 					f = retflag[i];
@@ -11978,7 +12066,7 @@ void autoskill(lifeform_t *lf) {
 						setattr(lf, f->val[0], f->val[1]);
 					}
 				}
-			}
+			//}
 			nweps++;
 		}
 		if (isfirearm(o) && canweild(lf, o)) {
@@ -14177,7 +14265,9 @@ int recruit(lifeform_t *lf) {
 			int result;
 			int difficulty;
 			int minmult,maxmult;
-			difficulty = 25 + ((gethitdice(player) - gethitdice(lf))*2);
+			// since you have to be at least speech=4(skilled) to ask someone to
+			// join, add +8 to difficulty (pr_skilled * 2)
+			difficulty = 25 + 8 + ((gethitdice(player) - gethitdice(lf))*2);
 			if (real_skillcheck(player, SC_SPEECH, difficulty, 0, &result)) {
 				minmult = 10;
 				maxmult = 20;
@@ -14613,7 +14703,8 @@ int sayphrase(lifeform_t *lf, enum SAYPHRASE what, int volume, int val0, char *t
 	int i,rv = B_FALSE;
 	char buf[BUFLEN];
 	char buf2[BUFLEN];
-	char *p;
+	char buf3[BUFLEN];
+	char *p,*p2;
 	race_t *r;
 	switch (what) {
 		case SP_ALLY_ATTACK:
@@ -14863,6 +14954,61 @@ int sayphrase(lifeform_t *lf, enum SAYPHRASE what, int volume, int val0, char *t
 			}
 			rv = say(lf, buf, volume);
 			break;
+		case SP_TRADEINFO_ACCEPT:
+			p = text;
+			p2 = buf2;
+			while (*p != '^') {
+				*p2 = *p;
+				p++; p2++;
+			}
+			*p2 = '\0';
+			p++;
+			// next one...
+			p2 = buf3;
+			while (*p != '\0') {
+				*p2 = *p;
+				p++; p2++;
+			}
+			*p2 = '\0';
+			switch (rnd(1,2)) {
+				case 1: snprintf(buf, BUFLEN, "I'll train you in %s...", buf3); break;
+				case 2: snprintf(buf, BUFLEN, "I can teach you %s...", buf3); break;
+			}
+			strcat(buf, "if you teach me ");
+			strcat(buf, buf2);
+
+			rv = say(lf, buf, volume);
+			break;
+		case SP_TRADEINFO_CANCEL:
+			switch (rnd(1,2)) {
+				case 1: snprintf(buf, BUFLEN, "Maybe another time, then."); break;
+				case 2: snprintf(buf, BUFLEN, "Fair enough."); break;
+			}
+			rv = say(lf, buf, volume);
+			break;
+		case SP_TRADEINFO_DECLINE_ALREADYDONE:
+			switch (rnd(1,3)) {
+				case 1: snprintf(buf, BUFLEN, "Thank you, but I have enough knowledge for now."); break;
+				case 2: snprintf(buf, BUFLEN, "I'm done with teaching for the moment."); break;
+				case 3: snprintf(buf, BUFLEN, "I'm sick of learning at the moment."); break;
+			}
+			rv = say(lf, buf, volume);
+			break;
+		case SP_TRADEINFO_DECLINE_OTHERBAD:
+			switch (rnd(1,2)) {
+				case 1: snprintf(buf, BUFLEN, "Thank you, but there is nothing I could teach you."); break;
+				case 2: snprintf(buf, BUFLEN, "I fear there is nothing you could learn from me."); break;
+			}
+			rv = say(lf, buf, volume);
+			break;
+		case SP_TRADEINFO_DECLINE_PLAYERBAD:
+			switch (rnd(1,3)) {
+				case 1: snprintf(buf, BUFLEN, "You teach ME something? I think not."); break;
+				case 2: snprintf(buf, BUFLEN, "Sorry, I don't believe there is anything you could teach me."); break;
+				case 3: snprintf(buf, BUFLEN, "No thank you, there's nothing I need from you."); break;
+			}
+			rv = say(lf, buf, volume);
+			break;
 		default:
 			break;
 	}
@@ -17413,6 +17559,96 @@ void timeeffectslf(lifeform_t *lf) {
 	notime = B_FALSE;
 }
 
+
+// returns TRUE if lf declines to teach.
+int tradeknowledge(lifeform_t *lf) {
+	int poss[MAXCANDIDATES], fromplayer, toplayer;
+	enum TRADEINFOTYPE tradetype[MAXCANDIDATES],fromplayertype, toplayertype;
+	int nposs = 0,sel;
+	char buf[BUFLEN],tradetext[BUFLEN],lfname[BUFLEN],ch;
+	char fromplayertext[BUFLEN],toplayertext[BUFLEN];
+
+	getlfname(lf, lfname);
+
+	// already traded?
+	if (lfhasflag(lf, F_DONEKNOWLEDGETRADE)) {
+		sayphrase(lf, SP_TRADEINFO_DECLINE_ALREADYDONE, SV_TALK, NA, NULL);
+		return B_TRUE;
+	}
+
+	// does the player have a skill which lf needs?
+	getteachableskills(player, lf, poss, tradetype, &nposs);
+	if (nposs) {
+		sel = rnd(0,nposs-1);
+		fromplayer = poss[sel];
+		fromplayertype = tradetype[sel];
+	} else {
+		sayphrase(lf, SP_TRADEINFO_DECLINE_PLAYERBAD, SV_TALK, NA, NULL);
+		return B_TRUE;
+	}
+	// does lf have a skill which the player needs?
+	getteachableskills(lf, player, poss, tradetype, &nposs);
+	if (nposs) {
+		if (getskill(player, SK_SPEECH) >= PR_EXPERT) {
+			int i;
+			// you can pick which one to learn.
+			snprintf(buf, BUFLEN, "What would you like to learn from %s?",lfname);
+			initprompt(&prompt, buf);
+			ch = 'a';
+			for (i = 0; i < nposs; i++) {
+				gettradeinfoname(poss[i], tradetype[i], buf);
+				addchoice(&prompt, ch++, buf, NULL, NULL, NULL);
+			}
+			addchoice(&prompt, '-', "(nothing)", NULL, NULL, NULL);
+			ch = getchoice(&prompt);
+			if (ch == '-') {
+				sayphrase(lf, SP_TRADEINFO_CANCEL, SV_TALK, NA, NULL);
+				return B_TRUE;
+			} else {
+				sel = ch - 'a';
+			}
+		} else {
+			sel = rnd(0,nposs-1);
+		}
+		toplayer = poss[sel];
+		toplayertype = tradetype[sel];
+	} else {
+		sayphrase(lf, SP_TRADEINFO_DECLINE_OTHERBAD, SV_TALK, NA, NULL);
+		return B_TRUE;
+	}
+
+	// at this point we can do a valid trade. make the offer.
+	// encode skill/spell names into a single string of the form:
+	//	fromplayer^toplayer
+	gettradeinfoname(fromplayer, fromplayertype, fromplayertext);
+	gettradeinfoname(toplayer, toplayertype, toplayertext);
+	sprintf(tradetext, "%s^%s",fromplayertext,toplayertext);
+
+	sayphrase(lf, SP_TRADEINFO_ACCEPT, SV_TALK, NA, tradetext);
+	more();
+	// confirm.
+	sprintf(buf, "Learn %s from %s", toplayertext, lfname);
+	ch = askchar(buf, "yn","y", B_TRUE, B_FALSE);	
+	if (ch == 'y') {
+		// lf learns skill
+		if (fromplayertype == TI_SKILL) {
+			giveskill(lf, fromplayer);
+		} else { // ie. spell
+			sprintf(buf, "pw:%d;", getspellpower(lf, fromplayer));
+			addflag(lf->flags, F_CANCAST, fromplayer, NA, NA, buf);
+		}
+		// player learns skill
+		if (toplayertype == TI_SKILL) {
+			giveskill(player, toplayer);
+		} else { // ie. spell
+			addflag(player->flags, F_CANCAST, toplayer, NA, NA, NULL);
+		}
+		// can't trade knowledge anymore
+		addflag(lf->flags, F_DONEKNOWLEDGETRADE, B_TRUE, NA, NA, NULL);
+	}
+	return B_FALSE;
+}
+
 // return B_TRUE on failure.
 int tryclimb(lifeform_t *lf, cell_t *where, char *towhat) {
 	// if you have a rope or there's an adjacent wall, you can try

lf.h

@@ -18,7 +18,7 @@ void applywalkdam(lifeform_t *lf, int dam, enum DAMTYPE damtype, object_t *o);
 int areallies(lifeform_t *lf1, lifeform_t *lf2);
 int areenemies(lifeform_t *lf1, lifeform_t *lf2);
 int armourfits(lifeform_t *lf, object_t *o, enum ERROR *reason);
-int askforinfo(lifeform_t *lf);
+int askforinfo(lifeform_t *lf, int diffmod);
 int askforpayment(lifeform_t *shk, lifeform_t *lf);
 char *assignnpcname(lifeform_t *lf);
 void autoskill(lifeform_t *lf);
@@ -241,6 +241,8 @@ float getstatmod(lifeform_t *lf, enum ATTRIB att);
 char *getskilldesc(enum SKILL id );
 char *getskillname(enum SKILL id );
 char *getskilllevelname(enum SKILLLEVEL sl);
+int getteachableskills(lifeform_t *teacher, lifeform_t *student, int *info, enum TRADEINFOTYPE *tradetype, int *ninfo );
+char *gettradeinfoname(int what, enum TRADEINFOTYPE tradetype, char *buf);
 int getthrowspeed(lifeform_t *lf);
 int getturnspeed(lifeform_t *lf);
 void getwantdistance(lifeform_t *lf, lifeform_t *victim, int *min, int *max, int attacking);
@@ -418,6 +420,7 @@ int takeoff(lifeform_t *lf, object_t *o);
 void taketime(lifeform_t *lf, long howlong);
 int throwat(lifeform_t *thrower, object_t *o, cell_t *where);
 void timeeffectslf(lifeform_t *lf);
+int tradeknowledge(lifeform_t *lf);
 int tryclimb(lifeform_t *lf, cell_t *where, char *towhat);
 int touch(lifeform_t *lf, object_t *o);
 void turntoface(lifeform_t *lf, cell_t *dstcell);

spell.c

@@ -10887,6 +10887,9 @@ char *getspellname(enum OBTYPE spellid, lifeform_t *lf, char *buf) {
 	return buf;
 }
 
+// at what power level COULD lf cast 'spellid' ?
+// note: doesn't matter if the lf doesn't actually have f_cancast / f_canwill,
+//       in this case the function will return the POTENTIAL power.
 int getspellpower(lifeform_t *lf, enum OBTYPE spellid) {
 	int power = 0;
 	int spelllev;
@@ -10896,7 +10899,6 @@ int getspellpower(lifeform_t *lf, enum OBTYPE spellid) {
 	int boost;
 	flag_t *f;
 
-
 	if (db) {
 		objecttype_t *ot;
 		ot = findot(spellid);