--[[--
Widget for displaying progress bar.

Configurable attributes:

 * width
 * height
 * margin_v  -- vertical margin for solid infill
 * margin_h  -- horizontal margin for solid infill
 * radius
 * bordersize
 * bordercolor
 * bgcolor
 * altcolor   -- alternate backrgound color for "alt" pages
 * rectdim    -- dim amount for infill
 * ticks (list)  -- default to nil, use this if you want to insert markers
 * tick_width
 * last  -- maximum tick, used with ticks

Example:

    local foo_bar = ProgressWidget:new{
        width = Screen:scaleBySize(400),
        height = Screen:scaleBySize(10),
        percentage = 50/100,
    }
    UIManager:show(foo_bar)

]]

local BD = require("ui/bidi")
local Blitbuffer = require("ffi/blitbuffer")
local Geom = require("ui/geometry")
local Widget = require("ui/widget/widget")
local Screen = require("device").screen

local ProgressWidget = Widget:new{
    width = nil,
    height = nil,
    margin_h = Screen:scaleBySize(3),
    margin_v = Screen:scaleBySize(1),
    radius = Screen:scaleBySize(2),
    bordersize = Screen:scaleBySize(1),
    bordercolor = Blitbuffer.COLOR_BLACK,
    bgcolor = Blitbuffer.COLOR_WHITE,
    altcolor = Blitbuffer.COLOR_LIGHT_GRAY,
    rectdim = 2/3,
    percentage = nil,
    ticks = nil,
    tick_width = Screen:scaleBySize(3),
    last = nil,
    fill_from_right = false,
    allow_mirroring = true,
    alt = nil, -- table with alternate pages to mark with different color (in the form {{ini1, len1}, {ini2, len2}, ...})
    _mirroredUI = BD.mirroredUILayout(),
    _orig_margin_v = nil,
    _orig_bordersize = nil,
}

function ProgressWidget:getSize()
    return { w = self.width, h = self.height }
end

function ProgressWidget:paintTo(bb, x, y)
    local my_size = self:getSize()
    self.dimen = Geom:new{
        x = x, y = y,
        w = my_size.w,
        h = my_size.h
    }
    if self.dimen.w == 0 or self.dimen.h == 0 then return end

    -- fill background
    bb:paintRoundedRect(x, y, my_size.w, my_size.h, self.bgcolor, self.radius)
    -- paint border
    bb:paintBorder(x, y,
                   my_size.w, my_size.h,
                   self.bordersize, self.bordercolor, self.radius)
    -- background for alternate pages (e.g. non-linear flows)
    if self.alt and self.alt[1] ~= nil then
        local bar_width = (my_size.w-2*self.margin_h)
        local y_pos = y + self.margin_v + self.bordersize
        local bar_height = my_size.h-2*(self.margin_v+self.bordersize)
        for i=1, #self.alt do
            local tick_x = bar_width*((self.alt[i][1]-1)/self.last)
            local width = bar_width*(self.alt[i][2]/self.last)
            width = math.ceil(tick_x + width)
            tick_x = math.floor(tick_x)
            width = width - tick_x
            if self._mirroredUI then
                tick_x = bar_width - tick_x - width
            end
            bb:paintRect(
                x + self.margin_h + tick_x,
                y_pos,
                width,
                bar_height,
                self.altcolor)
        end
    end
    -- paint percentage infill
    -- note that "lightenRect" is misleading, it actualy darkens stuff
    if self.percentage >= 0 and self.percentage <= 1 then
        if self.fill_from_right or (self._mirroredUI and not self.fill_from_right) then
            bb:lightenRect(x+self.margin_h + math.ceil((my_size.w-2*self.margin_h)*(1-self.percentage)),
                    math.ceil(y+self.margin_v+self.bordersize),
                    math.ceil((my_size.w-2*self.margin_h)*self.percentage),
                    my_size.h-2*(self.margin_v+self.bordersize),
                    self.rectdim)
        else
            bb:lightenRect(x+self.margin_h,
                    math.ceil(y+self.margin_v+self.bordersize),
                    math.ceil((my_size.w-2*self.margin_h)*self.percentage),
                    my_size.h-2*(self.margin_v+self.bordersize),
                    self.rectdim)
        end
    end
    -- ticks
    if self.ticks and self.last and self.last > 0 then
        local bar_width = (my_size.w-2*self.margin_h)
        local y_pos = y + self.margin_v + self.bordersize
        local bar_height = my_size.h-2*(self.margin_v+self.bordersize)
        for i, tick in ipairs(self.ticks) do
            local tick_x = bar_width*(tick/self.last)
            if self._mirroredUI then
                tick_x = bar_width - tick_x
            end
            bb:paintRect(
                x + self.margin_h + tick_x,
                y_pos,
                self.tick_width,
                bar_height,
                self.bordercolor)
        end
    end
end

function ProgressWidget:setPercentage(percentage)
    self.percentage = percentage
end

function ProgressWidget:getPercentageFromPosition(pos)
    if not pos or not pos.x then
        return nil
    end
    local width = self.dimen.w - 2*self.margin_h
    local x = pos.x - self.dimen.x - self.margin_h
    if x < 0 or x > width then
        return nil
    end
    if BD.mirroredUILayout() then
        x = width - x
    end
    return x / width
end

function ProgressWidget:setHeight(height)
    self.height = Screen:scaleBySize(height)
    -- Adjust vertical margin and border size to ensure there's
    -- at least 1 pixel left for the actual bar
    self._orig_margin_v = self._orig_margin_v or self.margin_v
    self._orig_bordersize = self._orig_bordersize or self.bordersize
    local margin_v_min = self._orig_margin_v > 0 and 1 or 0
    local bordersize_min = self._orig_bordersize > 0 and 1 or 0
    self.margin_v = math.min(self._orig_margin_v, math.floor((self.height - 2*self._orig_bordersize - 1) / 2))
    self.margin_v = math.max(self.margin_v, margin_v_min)
    self.bordersize = math.min(self._orig_bordersize, math.floor((self.height - 2*self.margin_v - 1) / 2))
    self.bordersize = math.max(self.bordersize, bordersize_min)
end

function ProgressWidget:updateStyle(thick, height)
    if thick then
        self.margin_h = Screen:scaleBySize(3)
        self.margin_v = Screen:scaleBySize(1)
        self.bordersize = Screen:scaleBySize(1)
        self.radius = Screen:scaleBySize(2)
        self.bgcolor = Blitbuffer.COLOR_WHITE
        self._orig_margin_v = nil
        self._orig_bordersize = nil
        if height then
            self:setHeight(height)
        end
    else
        self.margin_h = 0
        self.margin_v = 0
        self.bordersize = 0
        self.radius = 0
        self.bgcolor = Blitbuffer.COLOR_GRAY
        self.ticks = nil
        self._orig_margin_v = nil
        self._orig_bordersize = nil
        if height then
            self:setHeight(height)
        end
    end
end

return ProgressWidget