local WidgetContainer = require("ui/widget/container/widgetcontainer")
local InputContainer = require("ui/widget/container/inputcontainer")
local Screen = require("device").screen
local UIManager = require("ui/uimanager")
local BlitBuffer = require("ffi/blitbuffer")

local CubePlugin = WidgetContainer:new{
    name = "3dcube",
}

function CubePlugin:init()
    self:onDispatcherRegisterActions()
    self.ui.menu:registerTouchMenuEntry({
        category = "tools",
        text = "Interactive 3D Cube",
        callback = function() self:showCube() end,
    })
end

function CubePlugin:onDispatcherRegisterActions()
    self.dispatcher:registerAction("3d_cube_show", {
        category = "tools",
        event = "Show3DCube",
        title = "Interactive 3D Cube",
        general = true,
    })
end

function CubePlugin:showCube()
    local CubeWidget = InputContainer:new{
        angleX = 0.4,
        angleY = 0.6,
        -- 8 vertices of a unit cube
        nodes = {
            {-1,-1,-1}, {1,-1,-1}, {1,1,-1}, {-1,1,-1},
            {-1,-1, 1}, {1,-1, 1}, {1,1, 1}, {-1,1, 1}
        },
        -- 12 connecting edges
        edges = {
            {1,2},{2,3},{3,4},{4,1},
            {5,6},{6,7},{7,8},{8,5},
            {1,5},{2,6},{3,7},{4,8}
        },
    }

    function CubeWidget:init()
        self.dimen = Screen:getBoundingRect()
        self.gesture_inst = {
            Pan = {
                gesture = "pan",
                touch_mode = "all",
            },
            Tap = {
                gesture = "tap",
                touch_mode = "all",
            }
        }
    end

    -- Update rotation angles when dragging a finger
    function CubeWidget:onPan(arg, ges)
        if ges.relative then
            self.angleY = self.angleY + (ges.relative.x * 0.015)
            self.angleX = self.angleX - (ges.relative.y * 0.015)
            UIManager:setDirty(self, "partial")
        end
        return true
    end

    -- Tap near the top edge to exit back to KOReader
    function CubeWidget:onTap(arg, ges)
        if ges.pos.y < 120 then
            UIManager:close(self)
        end
        return true
    end

    function CubeWidget:paintTo(bb, x, y)
        -- Clear screen with white background
        bb:paintRect(0, 0, Screen:getWidth(), Screen:getHeight(), BlitBuffer.COLOR_WHITE)

        local fov, distance = 350, 3.5
        local cx, cy = Screen:getWidth() / 2, Screen:getHeight() / 2

        -- 3D to 2D Perspective Projection
        local projected = {}
        for i, p in ipairs(self.nodes) do
            -- Rotate around Y axis (yaw)
            local x1 = p[1] * math.cos(self.angleY) + p[3] * math.sin(self.angleY)
            local z1 = -p[1] * math.sin(self.angleY) + p[3] * math.cos(self.angleY)
            -- Rotate around X axis (pitch)
            local y2 = p[2] * math.cos(self.angleX) - z1 * math.sin(self.angleX)
            local z2 = p[2] * math.sin(self.angleX) + z1 * math.cos(self.angleX)
            -- Divide by Z depth
            local sz = z2 + distance
            projected[i] = {
                x = math.floor(cx + (x1 * fov) / sz),
                y = math.floor(cy + (y2 * fov) / sz)
            }
        end

        -- Draw wireframe lines
        for _, edge in ipairs(self.edges) do
            local p1, p2 = projected[edge[1]], projected[edge[2]]
            bb:drawLine(p1.x, p1.y, p2.x, p2.y, BlitBuffer.COLOR_BLACK, 4)
        end
    end

    UIManager:show(CubeWidget)
end

return CubePlugin