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

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 = 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

-- Returns local coords from global
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

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