local Vec3 = require "lib/vec3"
local tree = require "lib/tree"

--- @class (exact) Camera
--- @field target Vec3
--- @field speed number
--- @field pixelsPerMeter integer
local camera = {
    target = Vec3 {},
    speed = 5,
    pixelsPerMeter = 100
}

function camera:update(dt)
    local ws = tree.instance().wheelscroll
    if ws.delta:length() > 0 then
        local worldDelta = ws.delta * (1 / self.pixelsPerMeter)
        self.target = self.target + worldDelta
        return
    end

    if love.keyboard.isDown("w") then self.target = self.target + Vec3({ 0, -dt * self.speed }) end
    if love.keyboard.isDown("a") then self.target = self.target + Vec3({ -dt * self.speed }) end
    if love.keyboard.isDown("s") then self.target = self.target + Vec3({ 0, dt * self.speed }) end
    if love.keyboard.isDown("d") then self.target = self.target + Vec3({ dt * self.speed }) end
end

function camera:attach()
    love.graphics.push()
    love.graphics.scale(self.pixelsPerMeter)
    love.graphics.translate(-self.target.x, -self.target.y)
end

function camera:detach()
    love.graphics.pop()
end

--- @return Camera
local function new()
    return setmetatable({}, {
        __index = camera
    })
end

return { new = new }