# vim:fileencoding=utf-8
# License: GPL v3 Copyright: 2018, Kovid Goyal <kovid at kovidgoyal.net>
from __python__ import bound_methods, hash_literals


if document?.caretPositionFromPoint:
    caret_position_from_point = document.caretPositionFromPoint.bind(document)
else:
    caret_position_from_point = def(x, y):
        r = document.caretRangeFromPoint(x, y)
        if r:
            return {'offsetNode': r.startContainer, 'offset': r.startOffset}
        return None


def word_boundary_regex():
    ans = word_boundary_regex.ans
    if ans is undefined:
        ans = word_boundary_regex.ans = /[\s!-#%-\x2A,-/:;\x3F@\x5B-\x5D_\x7B}\u00A1\u00A7\u00AB\u00B6\u00B7\u00BB\u00BF\u037E\u0387\u055A-\u055F\u0589\u058A\u05BE\u05C0\u05C3\u05C6\u05F3\u05F4\u0609\u060A\u060C\u060D\u061B\u061E\u061F\u066A-\u066D\u06D4\u0700-\u070D\u07F7-\u07F9\u0830-\u083E\u085E\u0964\u0965\u0970\u0AF0\u0DF4\u0E4F\u0E5A\u0E5B\u0F04-\u0F12\u0F14\u0F3A-\u0F3D\u0F85\u0FD0-\u0FD4\u0FD9\u0FDA\u104A-\u104F\u10FB\u1360-\u1368\u1400\u166D\u166E\u169B\u169C\u16EB-\u16ED\u1735\u1736\u17D4-\u17D6\u17D8-\u17DA\u1800-\u180A\u1944\u1945\u1A1E\u1A1F\u1AA0-\u1AA6\u1AA8-\u1AAD\u1B5A-\u1B60\u1BFC-\u1BFF\u1C3B-\u1C3F\u1C7E\u1C7F\u1CC0-\u1CC7\u1CD3\u2010-\u2027\u2030-\u2043\u2045-\u2051\u2053-\u205E\u207D\u207E\u208D\u208E\u2329\u232A\u2768-\u2775\u27C5\u27C6\u27E6-\u27EF\u2983-\u2998\u29D8-\u29DB\u29FC\u29FD\u2CF9-\u2CFC\u2CFE\u2CFF\u2D70\u2E00-\u2E2E\u2E30-\u2E3B\u3001-\u3003\u3008-\u3011\u3014-\u301F\u3030\u303D\u30A0\u30FB\uA4FE\uA4FF\uA60D-\uA60F\uA673\uA67E\uA6F2-\uA6F7\uA874-\uA877\uA8CE\uA8CF\uA8F8-\uA8FA\uA92E\uA92F\uA95F\uA9C1-\uA9CD\uA9DE\uA9DF\uAA5C-\uAA5F\uAADE\uAADF\uAAF0\uAAF1\uABEB\uFD3E\uFD3F\uFE10-\uFE19\uFE30-\uFE52\uFE54-\uFE61\uFE63\uFE68\uFE6A\uFE6B\uFF01-\uFF03\uFF05-\uFF0A\uFF0C-\uFF0F\uFF1A\uFF1B\uFF1F\uFF20\uFF3B-\uFF3D\uFF3F\uFF5B\uFF5D\uFF5F-\uFF65]/
    return ans


def expand_offset_to_word(string, offset):
    start = offset
    pat = word_boundary_regex()
    while start >= 1 and not pat.test(string.charAt(start - 1)):
        start -= 1
    end, sz = offset, string.length
    while end < sz and not pat.test(string.charAt(end)):
        end += 1
    return {'word': string[start:end], 'start': start, 'end': end}


def word_at_point(x, y):
    p = caret_position_from_point(x, y)
    if p and p.offsetNode?.nodeType is Node.TEXT_NODE:
        word_info = expand_offset_to_word(p.offsetNode.data, p.offset)
        if word_info.word:
            r = document.createRange()
            r.setStart(p.offsetNode, word_info.start)
            r.setEnd(p.offsetNode, word_info.end)
            return r


def first_visible_word():
    width = window.innerWidth
    height = window.innerHeight
    xdelta = width // 10
    ydelta = height // 10
    for y in range(0, height, ydelta):
        for x in range(0, width, xdelta):
            r = word_at_point(x, y)
            if r?:
                return r

def empty_range_extents():
    return {
        'start': {'x': 0, 'y': 0, 'height': 0, 'width': 0, 'onscreen': False, 'selected_prev': False},
        'end':   {'x': 0, 'y': 0, 'height': 0, 'width': 0, 'onscreen': False, 'selected_prev': False}
    }

# Returns a node that we know will produce a reasonable bounding box closest to the start or end
# of the DOM tree from the specified node.
# Currently: safe_nodes and text nodes.
# This a depth first traversal, with the modification that if a node is reached that meets the criteria,
# the traversal stops, because higher nodes in the DOM tree always have larger bounds than their children.
safe_nodes = {'img': True, 'br': True, 'hr': True}

def get_selection_node_at_boundary(node, start):
    stack = v'[]'
    stack.push({'node': node, 'visited': False})
    while stack.length > 0:
        top = stack[-1]
        # If the top node is a target type, we know that no nodes below it can be more to the start or end
        # than it, so return it immediately.
        name = top.node.nodeName.toLowerCase() if top.node.nodeName else ''
        if top.node.nodeType is Node.TEXT_NODE or safe_nodes[name]:
            return top.node
        # Otherwise, depth-first traversal.
        else if top.visited:
            stack.pop()
        else:
            top.visited = True
            if top.node.childNodes:
                for c in top.node.childNodes if start else reversed(top.node.childNodes):
                    stack.push({'node': c, 'visited': False})


def range_extents(q, in_flow_mode):
    ans = empty_range_extents()
    if not q:
        return ans
    start = q.cloneRange()
    end = q.cloneRange()

    def rect_onscreen(r):
        # we use -1 rather than zero for the top limit because on some
        # platforms the browser engine returns that for top line selections.
        # See https://bugs.launchpad.net/calibre/+bug/2024375/ for a test case.
        if r.right <= window.innerWidth and r.bottom <= window.innerHeight and r.left >= 0 and r.top >= -1:
            return True
        return False

    def apply_rect_to_ans(rect, ans):
        ans.x = Math.round(rect.left)
        ans.y = Math.round(rect.top)
        ans.height = Math.round(rect.height)
        ans.width = Math.round(rect.width)
        ans.onscreen = rect_onscreen(rect)
        return ans

    def for_boundary(r, ans, is_start):
        rect = r.getBoundingClientRect()
        if rect.height is 0 and rect.width is 0:
            # this tends to happen when moving the mouse downwards
            # at the boundary between paragraphs
            if r.startContainer?.nodeType is Node.ELEMENT_NODE:
                node = r.startContainer
                if r.startOffset and node.childNodes.length > r.startOffset:
                    node = node.childNodes[r.startOffset]

                boundary_node = get_selection_node_at_boundary(node, is_start)
                # If we found a node that will produce a reasonable bounding box at a boundary, use it:
                if boundary_node:
                    if boundary_node.nodeType is Node.TEXT_NODE:
                        if is_start:
                            r.setStart(boundary_node, boundary_node.length - 1)
                            r.setEnd(boundary_node, boundary_node.length)
                        else:
                            r.setStart(boundary_node, 0)
                            r.setEnd(boundary_node, 1)
                        rect = r.getBoundingClientRect()
                    else:
                        rect = boundary_node.getBoundingClientRect()
                        if not is_start:
                            ans.selected_prev = True
                # we cant use getBoundingClientRect as the node might be split
                # among multiple columns
                else if node.getClientRects:
                    rects = node.getClientRects()
                    if rects.length:
                        erect = rects[0]
                        rect = {'left': erect.left, 'top': erect.top, 'right': erect.left + 2, 'bottom': erect.top + 2, 'width': 2, 'height': 2}
        apply_rect_to_ans(rect, ans)

    if q.startContainer.nodeType is Node.ELEMENT_NODE:
        start.collapse(True)
        for_boundary(start, ans.start, True)
    elif q.startOffset is 0 and q.startContainer.length is 0:
        start.collapse(True)
        for_boundary(start, ans.start, True)
    elif q.startOffset is q.startContainer.length:
        start.setStart(q.startContainer, q.startOffset - 1)
        start.setEnd(q.startContainer, q.startOffset)
        rect = start.getBoundingClientRect()
        apply_rect_to_ans(rect, ans.start).selected_prev = True
    else:
        start.setStart(q.startContainer, q.startOffset)
        start.setEnd(q.startContainer, q.startOffset + 1)
        rect = start.getBoundingClientRect()
        apply_rect_to_ans(rect, ans.start)

    if q.endContainer.nodeType is Node.ELEMENT_NODE:
        end.collapse(False)
        for_boundary(end, ans.end, False)
    elif q.endOffset is 0 and q.endContainer.length is 0:
        end.collapse(False)
        for_boundary(end, ans.end, False)
    elif q.endOffset is q.endContainer.length:
        end.setStart(q.endContainer, q.endOffset - 1)
        end.setEnd(q.endContainer, q.endOffset)
        rect = end.getBoundingClientRect()
        apply_rect_to_ans(rect, ans.end).selected_prev = True
    else:
        end.setStart(q.endContainer, q.endOffset)
        end.setEnd(q.endContainer, q.endOffset + 1)
        rect = end.getBoundingClientRect()
        apply_rect_to_ans(rect, ans.end)

    if ans.end.height is 2 and ans.start.height > 2:
        ans.end.height = ans.start.height
    if ans.start.height is 2 and ans.end.height > 2:
        ans.start.height = ans.end.height
    return ans



def selection_extents(in_flow_mode):
    sel = window.getSelection()
    if not sel or not sel.rangeCount or sel.isCollapsed:
        return empty_range_extents()
    return range_extents(sel.getRangeAt(0), in_flow_mode)


def is_start_closer_to_point(pos):
    sel = window.getSelection()
    if not sel.rangeCount:
        return
    p = caret_position_from_point(pos.x, pos.y)
    if p:
        r = sel.getRangeAt(0)
        sr = document.createRange()
        sr.setStart(r.startContainer, r.startOffset)
        sr.setEnd(p.offsetNode, p.offset)
        er = document.createRange()
        er.setStart(p.offsetNode, p.offset)
        er.setEnd(r.endContainer, r.endOffset)
        return sr.toString().length < er.toString().length
    return False


def move_end_of_selection(pos, start):
    sel = window.getSelection()
    if not sel.rangeCount:
        return
    p = caret_position_from_point(pos.x, pos.y)
    if not p:
        return
    r = sel.getRangeAt(0)
    if start is None:
        q = document.createRange()
        q.setStart(p.offsetNode, p.offset)
        q.setEnd(p.offsetNode, p.offset)
        if r.compareBoundaryPoints(window.Range.START_TO_START, q) >= 0:
            start = True
        elif r.compareBoundaryPoints(window.Range.END_TO_END, q) <= 0:
            start = False
        else:
            # point is inside the selection
            start = False
    new_range = document.createRange()
    if start:
        new_range.setStart(p.offsetNode, p.offset)
        new_range.setEnd(r.endContainer, r.endOffset)
        other_boundary_changed = r.endContainer is not new_range.endContainer or r.endOffset is not new_range.endOffset
    else:
        new_range.setStart(r.startContainer, r.startOffset)
        new_range.setEnd(p.offsetNode, p.offset)
        other_boundary_changed = r.startContainer is not new_range.startContainer or r.startOffset is not new_range.startOffset
    if new_range.collapsed and other_boundary_changed:
        # we ignore the case when the new range is collapsed and the other end
        # of the selection is also moved as this is a chromium bug. See https://bugs.launchpad.net/bugs/2054934
        return
    sel.removeAllRanges()
    sel.addRange(new_range)
