import curses
import dbLayer as db
from bookForm import bookForm

class browserWindow:
    hl=0
    entries = []
    topline = 0
    # column definitions are in (label, weight, specified width) triples
    columnDefs = [('ID',0,3),
                  ('ISBN',0,13),
                  ('Authors',30,None),
                  ('Title',60,None)]
    mx = my = 0


    def clear(self):
        self.w.erase()
        self.w.refresh()

    def __init__(self,window):
        self.w = window
        self.updateGeometry()
        self.refreshBooks()

    def sortByColumn(self, col):
        self.entries.sort() # key=dict.get(col))

    def updateGeometry(self):
        (self.my,self.mx)=self.w.getmaxyx()
        self.pageSize = self.my-3
        self.calcColWidths()

    def calcColWidths(self):
        total_weights = 0
        available_space = self.mx - len(self.columnDefs)
        cols = []
        for label,weight,value in self.columnDefs:
            if value!=None:
                available_space -= value
            else:
                total_weights+=weight

        for label,weight,value in self.columnDefs:
            if value!=None:
                cols.append((label,value))
            else:
                cols.append((label,available_space*weight/total_weights))
        self.columns=cols

    def refresh(self):
        self.displayHeader()
        for r in range(0,self.pageSize):
            self.displayRow(r)
        self.w.refresh()
        self.highlight()

    def displayHeader(self):
        cursor = 0
        for header,width in self.columns:
            self.w.addnstr(0,cursor,header,width)
            self.w.addstr(1,cursor,"-"*width)
            cursor += width+1

    def displayRow(self,row):
        if self.topline+row < len(self.entries):
            entry = self.entries[self.topline+row]
            cursor = 0
            for k,width in self.columns:
                if k.lower() in entry:
                    self.w.addnstr(row+2,cursor,str(entry[k.lower()])+" "*width,width)
                cursor += width+1
        else:
            self.w.addstr(row+2,0," "*self.mx)

    def highlight(self):
        row = self.hl-self.topline+2
        if row > 1 and row < self.my:
            self.w.chgat(row,0,self.mx,curses.A_REVERSE)

    def unHighlight(self):
        row = self.hl-self.topline+2
        if row > 1 and row < self.my:
            self.w.chgat(row,0,self.mx,curses.A_NORMAL)

    def mvHighlight(self,delta):
        new = self.hl+delta
        new = max(new,0)
        new = min(new,len(self.entries)-1)
        self.unHighlight()
        self.hl = new
        self.highlight()
    
    def scroll(self,delta):
        self.unHighlight()
        self.topline += delta
        self.topline = max(self.topline,0)
        self.topline = min(self.topline,len(self.entries)-1)
        self.refresh()

    def eventLoop(self):
        self.w.keypad(1)
        self.refresh()

        ch = self.w.getch()
        while ch != 27 and ch != 113:
            self.handleInput(ch)
            self.w.refresh()
            ch = self.w.getch()

    def handleInput(self,ch):
        if ch == curses.KEY_UP:
            if self.hl == self.topline:
                self.scroll(-self.pageSize/2-1)
            self.mvHighlight(-1)
        elif ch == curses.KEY_DOWN:
            if self.hl == self.topline+self.pageSize-1:
                self.scroll(+self.pageSize/2+1)
            self.mvHighlight(+1)
        elif ch == curses.KEY_PPAGE:
            self.scroll(-self.pageSize)
            self.mvHighlight(-self.pageSize)
        elif ch == curses.KEY_NPAGE:
            self.scroll(+self.pageSize)
            self.mvHighlight(+self.pageSize)



class bookBrowser(browserWindow):
    # redefinable functions
    def updateSelection(self,book):
        bookid = book['id']
        
        w=curses.newwin(1,1,20,20)
        bf=bookForm(w)
        bf.caption='Update Book '+str(bookid)
        bf.blabel='update'
        bf.updateEntries(book)
        newbook = bf.eventLoop()
        if len(newbook)!=0:
            db.updateBook(newbook,bookid)
        bf.clear()

    def viewSelection(self,book):
        bookid = book['id']
        w=curses.newwin(1,1,20,20)
        bf = bookForm(w)
        bf.caption='Viewing Book '+str(bookid)
        bf.blabel='done'
        bf.updateEntries(book)
        bf.eventLoop()
        bf.clear()

    def refreshBooks(self):
        self.entries = db.getBooks()

    def handleInput(self,ch):
        browserWindow.handleInput(self,ch)
        if ch == 117: #update on 'u'
            book = self.entries[self.hl]
            self.updateSelection(entries)
            self.entries[self.hl]=db.getBookByID(book['id'])
            self.refresh()
        elif ch == 10:
            book = self.entries[self.hl]
            self.viewSelection(book)
            self.refresh()