"""Tests to see if pageorg is working correctly. These tests
originally came from the U. Wisconsin-Madison Minibase project, which
I ported to Java, which I then ported to Python. Note that these tests
running to completion does not indicate that your code is correct:
you've got to get the output right."""

import pageorg
import array
import random

class TestException(Exception):
    pass


def test1():
    page = pageorg.makePage()
    pageorg.setup(page)

    print "--- Test 1: Page Initialization Checks ---"
    print "Available Space: " , pageorg.getAvailableSpace(page)

    if not pageorg.empty(page):
        raise TestException("Page should be empty.")

    print "Page Empty as expected."
    pageorg.dumpPage(page);


def test2():
    buffSize = 20
    limit = 20
    tmpBuf = array.array('c','a'*buffSize)

    page = pageorg.makePage()
    pageorg.setup(page)

    print "--- Test 2: Insert and traversal of records ---"
    for i in range(limit):
        rid = pageorg.insertRecord(page,tmpBuf)
        print "Inserted record, RID", str(rid)
        rid = pageorg.nextRecord(page,rid)

    if pageorg.empty(page):
        raise TestException("The page cannot be empty")
            
    rid = pageorg.firstRecord(page)
    while rid != None:
        tmpBuf = pageorg.getRecord(page,rid)
        print "Retrieved record, RID", str(rid)
        rid = pageorg.nextRecord(page,rid)

    pageorg.dumpPage(page)

def test3():
    buffSize = 20
    limit = 20
    tmpBuf = array.array('c','\0'*buffSize)

    page = pageorg.makePage()
    pageorg.setup(page)

    print "--- Test 3: Insert and delete fixed sized records ---"
    for i in range(limit):
        rid = pageorg.insertRecord(page,tmpBuf)
        print "Inserted record, RID", str(rid)
        rid = pageorg.nextRecord(page,rid)

    if pageorg.empty(page):
        raise TestException("The page cannot be empty");

    rid = pageorg.firstRecord(page)
    deleteList = []
    i=0
    prevRid = None
    while rid != None:
        tmpBuf = pageorg.getRecord(page,rid)
        if (i%4==0) and (4*i<3*limit):
            deleteList.append(rid)
        prevRid = rid
        rid = pageorg.nextRecord(page,rid)
        i+=1

    deleteList.append(prevRid) # pick up the last one

    print "Deleting Records"
    for curRid in deleteList:
        print "Deleting Rid", str(curRid)
        if not pageorg.deleteRecord(page,curRid):
            raise TestException("Deletion of rid" + str(curRid) + \
                                      "failed")

                                      
    print "After Deletion."
    rid = pageorg.firstRecord(page)
    while rid != None:
        print "Retrieving record ", str(rid)
        tmpBuf = pageorg.getRecord(page,rid)
        rid = pageorg.nextRecord(page,rid)


def test4():
    buffSize = 50
    limit = 20
    string1 = "Alphabet:"
    string2 = "Junk:"

    page = pageorg.makePage()
    pageorg.setup(page)

    print("--- Test 4: Insert and delete variable-length records ---")
    for i in range(limit):
        letter = chr(i+65)
        if i%2 == 0:
            string1 = string1 + letter
            print string1
            pageorg.insertRecord(page,array.array('c',string1))
        else:
            string2 = string2 + letter
            print string2
            pageorg.insertRecord(page,array.array('c',string2))

    if pageorg.empty(page):
        raise TestException("The page cannot be empty");

    rid = pageorg.firstRecord(page);
    deleteList = []
    i=0;
    j=0;
    prevRid = None
    while rid != None:
        if (j%4==0) and (4*j<3*limit):
            deleteList.append(rid)
            i +=1

        # if compaction is taking place, we shall see
        prevRid = rid
        rid = pageorg.nextRecord(page,rid)
        j +=1
    deleteList.append(prevRid) # pick up the last one

    pageorg.dumpPage(page)

    print "Deleting Records"
    for curRid in deleteList:
        print "Deleting Rid", curRid
        if not pageorg.deleteRecord(page,curRid):
            raise TestException("Deletion of rid", rid, "failed")

    rid = pageorg.firstRecord(page)
    while rid != None:
        print "Retrieving record ",rid
        print pageorg.getRecord(page,rid).tostring()
        rid = pageorg.nextRecord(page,rid)

    pageorg.dumpPage(page)


def test5():
    longStr = ""
    for i in range(2000):
        longStr = longStr + (chr)(i%26+65)

    print "--- Test 5: Test some error conditions ---"

    page = pageorg.makePage()
    pageorg.setup(page)

    # Deletion of empty page
    rid = -6
    if  pageorg.deleteRecord(page,rid):
        raise TestException("Empty space deletion.")
    print "No record is deleted."

    # FirstRecord of empty page
    rid = pageorg.firstRecord(page);
    if rid != None:
        raise TestException("None should be returned for an empty page.")
    print "FirstRecord in an empty page is handled correctly."

    # NextRecord of empty page
    try:
        curRid = pageorg.nextRecord(page,rid)
        raise TestException("nextRecord should not have succeeded(1)")
    except Exception, e:
        print "nextRecord handled correctly(1)."

    try:
        curRid = -6
        curRid = pageorg.nextRecord(page,curRid)
        raise TestException("nextRecord should not have succeeded(2)")
    except Exception,e:
        print "nextRecord handled correctly(2)."

    # Overfilling pages
    try:
        pageorg.insertRecord(page,array.array('c',longStr))
        raise TestException("Inserting long string should have failed")
    except Exception, e:
        print "Overflow handled correctly"

def test6():
    print "--- Test 6 ---"

    page = pageorg.makePage()
    pageorg.setup(page)

    initialSpace = pageorg.getAvailableSpace(page)
    print "Initial available space =",initialSpace

    maxStr = " "*initialSpace
  
    rid = pageorg.insertRecord(page,array.array('c',maxStr))
    if not pageorg.deleteRecord(page,rid):
        raise TestException("Failed to delete maximum size record.")

    secondSpace = pageorg.getAvailableSpace(page)
    print "Second available space =", secondSpace
    if secondSpace != initialSpace:
        raise TestException("Free space has changed")

    # insert as many records of random size as will fit
    records = []
    random.seed(90125)
    longStr = ""
    for i in range(2000):
        longStr = longStr + (chr)(i%26+65)

    try:
        while True:
            data = longStr[0:random.randint(1,10)]
            print 'Inserting',data
            rid = pageorg.insertRecord(page,array.array('c',data))
            records.append((rid,data))
    except pageorg.PageFullException,e:
        pass

    print "Inserted", len(records),"records"

    print "Start of deletion"
    print "space = ",pageorg.getAvailableSpace(page)
    while len(records) > 0:
        curRec = random.randrange(0,len(records))
        record = pageorg.getRecord(page,records[curRec][0]).tostring()
      
        if len(record) != len(records[curRec][1]):
            print "ERROR: record", curRec, "has length", len(record), \
                  "and should be", len(records[curRec][1])
        if record != records[curRec][1]:
            print "ERROR: record", curRec, "has value", record, \
                  "and should be", records[curRec][1]

        print 'Deleting',record

        if not pageorg.deleteRecord(page,records[curRec][0]):
            print "ERROR: failed to delete record",curRec

        records.pop(curRec)

    print "End of deletion"

    finalSpace = pageorg.getAvailableSpace(page)
    if finalSpace != initialSpace:
        raise TestException("Final free space does not match initial")


def runTest(test):
    success = True
    try:
        test()
    except TestException, e:
        print 'Test Exception thrown'
        success = False
        print e
        return success;

runTest(test1)
runTest(test2)
runTest(test3)
runTest(test4)
runTest(test5)
runTest(test6)