local icons = require("lib.utils.sprite_atlas").load(Tree.assets.files.dev_icons)
local easing = require "lib.utils.easing"
local AnimationNode = require "lib.animation_node"
local Element = require "lib.simple_ui.element"
local Rect = require "lib.simple_ui.rect"

--- @class SkillButton : UIElement
--- @field hovered boolean
--- @field selected boolean
--- @field onClick function?
--- @field icon string
local skillButton = setmetatable({}, Element)
skillButton.__index = skillButton

function skillButton:update(dt)
    local mx, my = love.mouse.getPosition()
    if self:hitTest(mx, my) then
        self.hovered = true
        if Tree.controls:isJustPressed("select") then
            if self.onClick then self.onClick() end
            Tree.controls:consume("select")
        end
    else
        self.hovered = false
    end
end

function skillButton:draw()
    love.graphics.push()
    love.graphics.applyTransform(self.transform)

    local r, g, b, a = love.graphics.getColor()

    if self.selected then
        love.graphics.setColor(0.3, 1, 0.3, a)
    elseif self.hovered then
        love.graphics.setColor(0.7, 1, 0.7, a)
    else
        love.graphics.setColor(1, 1, 1, a)
    end

    love.graphics.translate(0, self.bounds.y)
    love.graphics.draw(icons.atlas, icons:pickQuad(self.icon))
    love.graphics.pop()
end

--- @class SkillRow : UIElement
--- @field characterId Id
--- @field selected SkillButton?
--- @field showNode AnimationNode?
--- @field showT number
--- @field hideNode AnimationNode?
--- @field hideT number
--- @field state "show" | "hide"
--- @field children SkillButton[]
local skillRow = setmetatable({}, Element)
skillRow.__index = skillRow

--- @param characterId Id
function skillRow.new(characterId)
    local t = {
        characterId = characterId,
        showT = 0,
        hideT = 0,
        state = "show",
        children = {}
    }

    setmetatable(t, skillRow)

    local char = Tree.level.characters[characterId]
    char:try(Tree.behaviors.spellcaster, function(behavior)
        for i, spell in ipairs(behavior.spellbook) do
            local skb = skillButton:new { icon = spell.tag }
            skb.onClick = function()
                skb.selected = not skb.selected
                if t.selected then t.selected.selected = false end
                t.selected = skb

                if not behavior.cast then
                    behavior.cast = behavior.spellbook[i]
                    behavior.state = "casting"
                else
                    behavior.state = "idle"
                    behavior.cast = nil
                end
            end
            t.children[i] = skb
        end
    end)

    return t
end

function skillRow:show(animationNode)
    self.state = "show"
    if self.showNode then self.showNode:finish() end
    self.showT = 0
    self.showNode = animationNode
end

function skillRow:hide(animationNode)
    self.state = "hide"
    if self.hideNode then self.hideNode:finish() end
    self.hideT = 0
    self.hideNode = animationNode
end

function skillRow:update(dt)
    if self.showT < 1 and self.state == "show" then
        self.showT = self.showT + dt / 0.3 -- в знаменателе продолжительность анимации в секундах
    elseif self.showNode then
        self.showNode:finish()
        self.showNode = nil
    end

    if self.hideT < 1 and self.state == "hide" then
        self.hideT = self.hideT + dt / 0.3
    elseif self.hideNode then
        self.hideNode:finish()
        self.hideNode = nil
    end

    local iconSize = icons.tileSize
    local scale = (64 / iconSize)
    local screenW, screenH = love.graphics.getDimensions()
    local padding = 8
    local count = #self.children

    self.bounds = Rect {
        width = count * icons.tileSize + (count - 1) * padding,
        height = iconSize,
        y = 10 * easing.easeInCubic(1 - self.showT)
    }
    self.transform = love.math.newTransform():translate(screenW / 2,
        screenH - 16):scale(scale, scale):translate(-self.bounds.width / 2, -iconSize)

    for i, skb in ipairs(self.children) do
        skb.bounds = Rect { height = iconSize, width = iconSize }
        skb.transform = self.transform:clone():translate(self.bounds.x + (i - 1) * iconSize +
            (i - 1) *
            padding,      -- левый край ряда + размер предыдущих иконок + размер предыдущих отступов
            self.bounds.y -- высота не меняется
        )
        skb:update(dt)
    end
end

function skillRow:draw()
    local alpha = self.state == "show" and easing.easeInSine(self.showT) or 1 - easing.easeInSine(self.hideT)
    love.graphics.setColor(1, 1, 1, alpha)
    for _, skb in ipairs(self.children) do
        skb:draw()
    end
end

local layout = {}
function layout:update(dt)
    local cid = Tree.level.selector:selected()
    if cid then
        self.skillRow = skillRow.new(cid)
        AnimationNode {
            function(animationNode)
                self.skillRow:show(animationNode)
            end,
        }:run()
    end
    if Tree.level.selector:deselected() then
        AnimationNode {
            function(animationNode)
                self.skillRow:hide(animationNode)
            end,
            onEnd = function()
                self.skillRow = nil
            end
        }:run()
    end
    if self.skillRow then self.skillRow:update(dt) end
end

function layout:draw()
    if self.skillRow then self.skillRow:draw() end
end

return layout