#!/bin/sh
# FILE: "/home/evmik/src/my_src/GradeBook/GradeBook.tcl"
# LAST MODIFICATION: "Wed, 15 Dec 2010 14:55:38 -0500 (evmik)"
# (C) 2010 by Eugeniy Mikhailov, <evgmik@gmail.com>
# $Id:$
# vim:set ft=tcl: \
exec tclsh "$0" "$@"

#load libtclsqlite3.so.0 Sqlite3
package require sqlite3
package require ncgi 
package require md5

::ncgi::parse

# defaults
set sortCol LastName
set user guest
set password guest
# defaults end

# read cookies
set user [::ncgi::cookie user]
set sortCol [::ncgi::cookie sortCol]
set password [::ncgi::cookie password]
set action [::ncgi::value action none]
# end of read cookies

if { [catch {set script_name $env(SCRIPT_NAME)} errStat] } { set script_name unknown}


# ########################## procs begin #################################
proc dbg {msg {level 1}} {
	if { $level <=2 } {
		set fid [open log a+]
		puts $fid $msg 
		close $fid
	}
}

set dbfile "./testdb"

#set url_base

sqlite3 db $dbfile

proc CreatePasswordsTable {db} {
	db eval {CREATE TABLE PasswordsTable(UserName text, PasswordHash text, GroupName text)}
	set eval_str [list INSERT INTO PasswordsTable VALUES('instructor', '[::md5::md5 -hex qwerty]', 'instructor')]
	db eval $eval_str
	set eval_str [list INSERT INTO PasswordsTable VALUES('ta', '[::md5::md5 -hex qwerty]', 'ta')]
	db eval $eval_str

	set eval_str [list INSERT INTO PasswordsTable VALUES('jhn', '[::md5::md5 -hex qwerty]', 'student')]
	db eval $eval_str
	set eval_str [list INSERT INTO PasswordsTable VALUES('ale', '[::md5::md5 -hex qwerty]', 'student')]
	db eval $eval_str
	set eval_str [list INSERT INTO PasswordsTable VALUES('dan', '[::md5::md5 -hex qwerty]', 'student')]
	db eval $eval_str
}

proc CreateGradesTable {db} {
	db eval {CREATE TABLE GradesTable(FirstName text, LastName text, UserName text,  HW01 real)}

	set eval_str [list INSERT INTO GradesTable VALUES('John','Lname1', 'jhn',   7)]
	db eval $eval_str
	set eval_str [list INSERT INTO GradesTable VALUES('Ale','Lname2', 'ale',   5)]
	db eval $eval_str
	set eval_str [list INSERT INTO GradesTable VALUES('Dan','Lname3', 'dan',   3)]
}

proc CreateAccessRightsTable {db} {
	db eval {CREATE TABLE AccessRightsTable(GroupName text,     sort integer,  addcolumn integer, deletecolumn integer)}
	db eval {INSERT INTO AccessRightsTable VALUES('instructor', 1,             1,                 1)}
	db eval {INSERT INTO AccessRightsTable VALUES('ta',         1,             1,                 1)}
	db eval {INSERT INTO AccessRightsTable VALUES('student',    1,             0,                 0)}
	# guest should have no rights make sure that 0 is evereywhere
	db eval {INSERT INTO AccessRightsTable VALUES('guest',      0,             0,                 0)}
}

proc htmlDBout {db {sort_col {}}} {
	#set x [db eval {SELECT * FROM GradesTable ORDER BY a}]
	#puts $x
	global script_name
	set defSortCol LastName

	# testing for the existense of the sorting column
	set eval_str [list SELECT * FROM GradesTable ORDER BY $sort_col]
	set err [catch {db eval $eval_str } errStat]
	if { $err } {
		dbg $errStat 3
		dbg "changing to default sorting column $defSortCol" 3
		set sort_col $defSortCol
	}

	set show_header 1
	if { $sort_col == {} } {
		set sort_col LastName
	} 
	# show the table with grades
	set eval_str [list SELECT * FROM GradesTable ORDER BY $sort_col]
	set err [catch {
			db eval $eval_str v {
				if { $show_header } {
					set show_header 0
					puts  {<table border="1">}
					puts  "<tr>"
					foreach col  $v(*) {
						puts -nonewline "<th><a href=$script_name?action=sort&sortCol=$col>$col</a></th>"
					}
					puts "</tr>"
					puts  "<tr>"
				} else {
					puts  "<tr>"
				}
				foreach index $v(*) {
					if { $index != "*" } {
						puts -nonewline "<td>$v($index)</td>"
					}
				}
				puts "</tr>"
			}
		} errStat ]
	if { $err } {
		dbg "we should never be here if $sortCol exist in the table" 1
		dbg $errStat 1

	}
	puts  "</table>"
}

proc htmlTop {permission_list} {
	array set permission $permission_list
	if { $permission(GroupName) == "guest" } {
		askToLogin
	} else {
		LogOffOption
	}

}

proc LogOffOption {} {
	global user password script_name
	puts "<div>"
	puts "You are logged in as $user do you wish to "
	puts "<a href=\"$script_name?action=logoff\">logoff</a>"
	puts "</div>"
	
}

proc askToLogin {} {
	global script_name
	puts "Please login <br>"
	puts "<form name=\"input\" action=\"$script_name\" method=\"post\" />"
	puts {Login: <input type="text" name="user"><br>}
	puts {Password: <input type="password" name="password"><br>}
	puts {<input type="hidden" name="action" value="logon"/>}
	puts {<input type="submit" value="Submit" />}
	puts {</form>}
}




proc CheckAccessRights { user password} {}
proc IsUserknown {} {return 1}

#proc SetLoginInfo {} {
	#global user password
	#set isAccessGranted [IsUserknown]
	#if { $isAccessGranted } {
		#dbg "access granted to user $user" 
	#}

	#set access_rights [CheckAccessRights $user $password]

#}

proc LogMeOn {} {
	global user password
	set user [::ncgi::value user guest]
	set password [::ncgi::value password guest]
	dbg "Logging in and setting cookies" 
	::ncgi::setCookie  -name user -value $user
	::ncgi::setCookie  -name password -value $password
}

proc LogMeOff {} {
	dbg "Logging off"
	global user password
	set user guest
	set password guest
	::ncgi::setCookie  -name user -value $user
	::ncgi::setCookie  -name password -value $password
	
}

proc SetSortColumn {} {
	global sortCol 
	set sortCol [::ncgi::value sortCol LastName]
	::ncgi::setCookie  -name sortCol -value $sortCol
}

proc ChoseAction {action permission_list} {
	array set permission $permission_list
	dbg "requested action: $action" 3
	switch $action {
		sort { 
			if { $permission(sort) } { SetSortColumn }
		} 
		default {   }
	}	
}

proc AccessGroupRights {db  user password } {
	dbg "access rights check for user: $user"
	if { $user == "guest"} {
		set group guest
	} else {
		set group instructor
	}
	set eval_str [list SELECT * FROM AccessRightsTable WHERE GroupName == '$group']
	db eval $eval_str permissions {}
	array unset permissions {\*}
	dbg "permissions for user $user are: [array get permissions]"
	return [array get permissions]
}

##################### end of procs ####################################
set timestamp [clock format [clock seconds] -format "%Y-%m-%dT%H:%M:%S"]

#CreatePasswordsTable db
#CreateGradesTable db
#CreateAccessRightsTable db
dbg [::ncgi::names] 4
# logon and logoff actions are granted to everyone
if { $action == "logon" } { LogMeOn }   
if { $action == "logoff" } { LogMeOff } 

dbg "Connection at $timestamp for user $user"
set permissions [AccessGroupRights db $user $password]
ChoseAction $action $permissions

::ncgi::header
htmlTop $permissions
htmlDBout db $sortCol