/*    /lib/pager.c
 *    from the Dead Souls Object Library
 *    a system pager for interactive objects
 *    created by Descartes of Borg 951104
 *    Version: @(#) pager.c 1.3@(#)
 *    Last modified: 96/10/18
 */

#include <function.h>
#include <message_class.h>
#include "include/pager.h"

static private int InPager = 0;

mixed more(mixed val, string cl, function f, mixed args) {
    log_file("more", sprintf("%O", previous_object()) + "\n");
    return eventPage(val, cl, f, args);
}

varargs mixed eventPage(mixed val, mixed msg_class, function f,mixed args...) {
    class page_file *files;
    int maxi;

    if( InPager ) return "You are already in the pager.";
    if( !stringp(val) && !arrayp(val) )
	error("Bad argument 1 to eventPage().\n");
    if( stringp(msg_class) || !msg_class ) msg_class = MSG_SYSTEM;
    if( arrayp(val) ) {
	class page_file file;

	file = new(class page_file);
	if( !(file->Size = sizeof(val)) ) return 1;
	file->MessageClass = msg_class;
	file->CurrentLine = 0;
	file->Lines = val;
	file->Callback = f;
	file->Args = args;
	file->Name = "";
	file->Marks = ([]);
	file->LastSearch = 0;
	files = ({ file });
    }
    else {
	string tmp;

	val = wild_card(val);
	if( !val || !sizeof(val) ) return "File not found.";
	files = ({});
	foreach(tmp in val) {
	    class page_file file;
	    string str;

	    if( file_size(tmp) == -2 ) {
		if( sizeof(val) == 1 ) return "That is a directory.";
		else continue;
	    }
	    str = read_file(tmp);
	    if( !str ) continue;
	    file = new(class page_file);
	    file->Name = tmp;
	    file->Lines = explode(str, "\n");
	    file->Size = sizeof(file->Lines);
	    file->MessageClass = msg_class;
	    file->CurrentLine = 0;
	    file->Callback = f;
	    file->Args = args;
	    file->Marks = ([]);
	    file->LastSearch = 0;
	    files += ({ file });
	}
    }
    if( (maxi = sizeof(files)) > 1 ) {
	int i;

	for(i=0; i<maxi; i++) {
	    if( i != maxi-1 ) {
		((class page_file)files[i])->Callback = (: Page, files[i+1] :);
		((class page_file)files[i])->Args = 0;
	    }
	}
    }
    if( ((class page_file)files[<1])->Args )
	((class page_file)files[<1])->Args =
	({ ((class page_file)files[<1])->Callback }) +
	((class page_file)files[<1])->Args;
    else ((class page_file)files[<1])->Args =
	({ ((class page_file)files[<1])->Callback });
    ((class page_file)files[<1])->Callback = (: RazzleDazzle :);
    Page(files[0]);
    return 1;
}

static void Page(class page_file file) {
    string page, prompt;
    int endline;

    endline = file->CurrentLine + (GetScreen()[1] - 3);
    if( endline < file->CurrentLine ) endline = file->CurrentLine;
    if( endline > (file->Size - 1) ) endline = file->Size - 1;
    page = implode(file->Lines[file->CurrentLine..endline], "\n");
    eventPrint(page, file->MessageClass);
    if( creatorp() && file->Name != "" ) prompt = file->Name + " ";
    else prompt = "";
    if( endline < file->Size - 1 ) {
	prompt += "(" + (file->CurrentLine+1) + "-" + (endline+1) + " ";
	prompt += ((endline * 100)/(file->Size - 1)) + "%) press enter: ";
	prompt = "%^BOLD%^" + prompt + "%^RESET%^";
	file->CurrentLine = endline + 1;
	eventPrint(prompt, MSG_PROMPT);
	input_to((: cmdPage :), file);
    }
    else {
	int fp;

	file->CurrentLine = endline;
	fp = functionp(file->Callback);
	if( !fp || (fp == FP_OWNER_DESTED) ) return;
	if( file->Args ) evaluate(file->Callback, file->Args...);
	else evaluate(file->Callback);
    }    
}

static void cmdPage(string str, class page_file file) {
    string *tmp;
    string cmd, args;
    int fp, x, scrlen;

    if( !str || trim(str) == "" ) {
	if( file->CurrentLine >= (file->Size) ) {
	    fp = functionp(file->Callback);
	    if( !fp || (fp == FP_OWNER_DESTED) ) return;
	    if( file->Args ) evaluate(file->Callback, file->Args...);
	    else evaluate(file->Callback);
	}
	else Page(file);
	return;
    }
    cmd = str[0..0];
    if( strlen(str) > 1 ) args = str[1..];
    else args = 0;
    switch(cmd) {
    case ",":
	if( !args || !(file->Marks[args]) ) {
	    receive("\a");
	    input_to((: cmdPage :), file);
	    return;
	}
	else cmdPage("g" + file->Marks[args], file);
	return;

    case "/":
	if( file->CurrentLine >= (file->Size - 1) ) {
	    eventPrint("\a" + GetPagerPrompt(file), MSG_PROMPT);
	    input_to((: cmdPage :), file);
	    return;
	}
	if( !args && !(file->LastSearch) ) {
	    eventPrint("\a" + GetPagerPrompt(file), MSG_PROMPT);
	    input_to((: cmdPage :), file);
	    return;
	}
	if( !args ) args = file->LastSearch;
	tmp = regexp(file->Lines[file->CurrentLine..], args);
	if( !sizeof(tmp) ) {
	    eventPrint("\a" + GetPagerPrompt(file), MSG_PROMPT);
	    input_to((: cmdPage :), file);
	    return;
	}
	for(x = file->CurrentLine; x < file->Size; x++) {
	    if( tmp[0] == file->Lines[x] ) break;
	}
	if( x == file->Size ) {
	    eventPrint("\a" + GetPagerPrompt(file), MSG_PROMPT);
	    input_to((: cmdPage :), file);
	    return;
	}
	file->CurrentLine = (x ? x-1 : x);
	file->LastSearch = args;
	Page(file);
	return;

    case "?":
	x = file->CurrentLine - GetScreen()[1] - 3;
	if( x < 1 ) {
	    eventPrint("\a" + GetPagerPrompt(file), MSG_PROMPT);
	    input_to((: cmdPage :), file);
	    return;
	}
	if( !args && !(file->LastSearch) ) {
	    eventPrint("\a" + GetPagerPrompt(file), MSG_PROMPT);
	    input_to((: cmdPage :), file);
	    return;
	}
	if( !args ) args = file->LastSearch;
	tmp = regexp(file->Lines[0..x], args);
	if( !sizeof(tmp) ) {
	    x = -1;
	}
	else {
	    for( ; x > -1; x--) {
		if( tmp[<1] == file->Lines[x] ) break;
	    }
	}
	if( x == -1 ) {
	    eventPrint("\a" + GetPagerPrompt(file), MSG_PROMPT);
	    input_to((: cmdPage :), file);
	    return;
	}
	file->CurrentLine = (x ? x - 1 : x);
	if( file->CurrentLine < 0 ) file->CurrentLine = 0;
	file->LastSearch = args;
	Page(file);
	return;

    case "b": 
	scrlen = GetScreen()[1];
	if( (file->CurrentLine - (2*(scrlen-3))) < 1 ) {
	    eventPrint("\a" + GetPagerPrompt(file), MSG_PROMPT);
	    input_to((: cmdPage :), file);
	    return;
	}
	else {
	    file->CurrentLine -= (2 * (scrlen-3));
	    Page(file);
	}
	return;

    case "g": case "<": case "G": case ">":
	if( cmd == "g" || cmd == "<" ) x = 1;
	else {
	    x = (file->Size - (GetScreen()[1] - 3));
	    if( x < 1 ) x = 1;
	}
	if( !args ) args = x + "";
	else if( args[0] == ' ') {
	    if( strlen(args) == 1 ) args = x + "";
	    else args = trim(args);
	}
	if( ((x = to_int(args)) < 1) || (x > file->Size) ) {
	    eventPrint("\a" + GetPagerPrompt(file), MSG_PROMPT);
	    input_to((: cmdPage :), file);
	    return;
	}
	file->CurrentLine = x - 1;
	Page(file);
	return;

    case "h": case "H":
	eventPrint(GetHelp("pager"), MSG_HELP);
	eventPrint(GetPagerPrompt(file), MSG_PROMPT);
	input_to((: cmdPage :), file);
	return;

    case "m":
	if( !args ) {
	    eventPrint("\a" + GetPagerPrompt(file), MSG_PROMPT);
	    input_to((: cmdPage :), file);
	    return;
	}
	file->Marks[args] = file->CurrentLine;
	eventPrint("Mark " + args + " set to line " +
	  (file->CurrentLine + 1) + ".", file->MessageClass);
	eventPrint(GetPagerPrompt(file), MSG_PROMPT);
	input_to((: cmdPage :), file);
	return;

    case "n":
	fp = functionp(file->Callback);
	if( !fp || (fp == FP_OWNER_DESTED) ) {
	    eventPrint("\a" + GetPagerPrompt(file), MSG_PROMPT);
	    input_to((: cmdPage :), file);
	    return;
	}
	if( file->Args ) evaluate(file->Callback, file->Args...);
	else evaluate(file->Callback);
	return;

    case "p": case "%":
	if( args ) x = to_int(args);
	if( !args || x < 1 || x > 100 ) {
	    eventPrint("\a" + GetPagerPrompt(file), MSG_PROMPT);
	    input_to((: cmdPage :), file);
	    return;
	}
	x = ((file->Size - 1) * x)/100 - 1;
	if( x < 0 ) x = 0;
	else if( x > ((file->Size - 1) - (GetScreen()[1] - 3)) )
	    x = ((file->Size - 1) - (GetScreen()[1] - 3));
	file->CurrentLine = x;
	Page(file);
	return;

    case "q":
	fp = functionp(file->Callback);
	if( !fp || (fp == FP_OWNER_DESTED) ) return;
	if( file->Args ) evaluate(file->Callback, file->Args...);
	else evaluate(file->Callback);
	return;

    case "v":
	eventPrint("Dead Souls Pager v3.0 by Descartes of Borg 951104",
	  MSG_HELP);
	eventPrint(GetPagerPrompt(file), MSG_PROMPT);
	input_to((: cmdPage :), file);
	return;

    default:
	eventPrint("\a'h' for help", MSG_ERROR);
	eventPrint(GetPagerPrompt(file), MSG_PROMPT);
	input_to((: cmdPage :), file);
	return;
    }
}

varargs static private void RazzleDazzle(mixed args...) {
    function f;

    InPager = 0;
    f = args[0];
    if( !functionp(f) || functionp(f) == FP_OWNER_DESTED ) return;
    if( sizeof(args) > 1 ) args = args[1..];
    else args = 0;
    if( args ) evaluate(f, args...);
    else evaluate(f);
}

static private string GetPagerPrompt(class page_file file) {
    int x;

    if( creatorp() && file->Name != "" )
	return "%^BOLD%^" + file->Name + ":%^RESET%^ ";
    if( file->CurrentLine >= (file->Size - 1) ) return "END: ";
    x = ((100 * file->CurrentLine)/(file->Size - 1));
    if( x < 0 ) x = 0;
    if( x > 100 ) x = 100;
    return "%^BOLD%^" + x + "%:%^RESET%^ ";
}

string GetHelp(string str) {
    if( str != "pager" ) return 0;
    return ("/<pattern>, ?<pattern>\n"
      "The pattern is optional.  / searches forward for a pattern.  "
      "If no pattern is specified, the last search pattern is "
      "repeated.  ? does the same, except searching backwards.\n"
      "b\n"
      "Move back one page.\n"
      "<return>\n"
      "Move ahead one page.\n"
      "n\n"
      "Move to the next file in the group of files being paged.\n"
      "m<tag>\n"
      "Mark the current line and asociate it with tag.  You can mark "
      "any number of lines.\n"
      ",<tag>\n"
      "Move to the named tag.\n"
      "g<line>, G<line>\n"
      "Go to the named line.  If no line is named, 'g' goes to the "
      "beginning of the file.  In contras, 'G' will go to the end.\n"
      "p<percent>\n"
      "Move to the line <percent> lines into the file.\n"
      "q\n"
      "Quit out of the pager.");
}