require "grid"
require "point"
require "line"

-- Returns local coords from global
local function snapCoords( point )
    local x = math.ceil( point.x / Config.cellSize )
    local y = math.ceil( point.y / Config.cellSize )
    return GridPoint:new( x, y )
end

local function vectorLength( startpoint, endpoint )
    return math.sqrt( ( startpoint.x - endpoint.x ) ^ 2 +  ( startpoint.y - endpoint.y ) ^ 2 )
end

function love.load()
    love.graphics.setLineStyle( Config.lineStyle )
    love.graphics.setLineWidth( Config.lineWidth )

    GameGrid = Grid:new( Point:new( 5, 5 ) )
    local line = Line:new(
        GridPoint:new( 1, 1 ),
        GridPoint:new( 3, 3 ),
        Color.red
    )
    GameGrid:push( line )
    local line1 = Line:new(
        GridPoint:new( 1, 5 ),
        GridPoint:new( 5, 2 ),
        Color.green
    )
    GameGrid:push( line1 )
    local line2 = Line:new(
        GridPoint:new( 2, 5 ),
        GridPoint:new( 5, 3 ),
        Color.blue
    )
    GameGrid:push( line2 )

    Mouse = {
        x = 0,
        y = 0,
        pressed = false,
        lastPressed = false,
        startX = -1,
        startY = -1,
        dragged = false,
        lastLine = nil,
        lastPoint = nil,
        point = Point:new( 0, 0 )
    }
end

-- TODO: move input interactions into module
-- TODO: fix collision with other line's endpoint
function love.update( dt )
    Mouse.x, Mouse.y = love.mouse.getPosition()
    Mouse.x = Mouse.x + 1
    Mouse.y = Mouse.y + 1
    Mouse.lastPoint = Mouse.point
    Mouse.lastPressed = Mouse.pressed
    Mouse.pressed = love.mouse.isDown( 1 )
    Mouse.point = snapCoords( Point:new( Mouse.x, Mouse.y ) )
    if Mouse.lastLine ~= nil then
        local pointsLen = #Mouse.lastLine.points
        local lastLinePoint = Mouse.lastLine.points[pointsLen]
        if vectorLength( Mouse.point, lastLinePoint ) == 1
            and GameGrid:inBounds( Mouse.point )
            and GameGrid:matchesLine( Mouse.point, true ) == nil
            and not lastLinePoint:equals( Mouse.lastLine.endpoint )
            and not GameGrid:isOtherEndpoint( Mouse.lastLine, Mouse.point ) then
            Mouse.lastLine:push( Mouse.point )
        elseif Mouse.lastLine:has( Mouse.point )
            and not Mouse.point:equals( lastLinePoint ) then
            while not Mouse.lastLine.points[#Mouse.lastLine.points]:equals( Mouse.point ) do
                Mouse.lastLine:pop()
            end
        end
    end


    Mouse.dragged = Mouse.pressed
        and Mouse.startX > 0
        and vectorLength(
            Point:new( Mouse.x, Mouse.y ),
            Point:new( Mouse.startX, Mouse.startY )
        ) > Config.dragSensivity

    if not Mouse.pressed and Mouse.startX > 0 then
        Mouse.startX = -1
        Mouse.startY = -1
        Mouse.lastLine = nil
    end

    if not Mouse.lastPressed
        and Mouse.pressed
        and Mouse.startX < 0 then
        Mouse.startX = Mouse.x
        Mouse.startY = Mouse.y
        Mouse.lastLine = GameGrid:matchesLine( Mouse.point, false )
    end
end

function love.draw()
    GameGrid:draw()

    local text = string.format( "%d:%d global\n%d:%d local\n%d:%d from start", Mouse.x, Mouse.y, Mouse.point.x, Mouse.point.y, Mouse.startX - Mouse.x, Mouse.startY - Mouse.y )
    love.graphics.print( text, 64, 256 )

    if Mouse.dragged then
        love.graphics.print( "drag", 64, 300 )
    end
    if Mouse.lastLine ~= nil then
            love.graphics.print( tostring( Mouse.lastLine ), 128, 300 )
    end
end