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"
local SkillRow = require "lib.simple_ui.level.skill_row"
local Color = require "lib.simple_ui.color"

--- @class BarElement : UIElement
--- @field getter fun() : number
--- @field value number
--- @field maxValue number
--- @field color Color
--- @field useDividers boolean
--- @field drawText boolean
local barElement = setmetatable({}, Element)
barElement.__index = barElement
barElement.useDividers = false
barElement.drawText = false

function barElement:update(dt)
    local val = self.getter()
    self.value = val < 0 and 0 or val > self.maxValue and self.maxValue or val
end

function barElement:draw()
    local valueWidth = self.bounds.width * self.value / self.maxValue
    local emptyWidth = self.bounds.width - valueWidth

    --- шум
    love.graphics.setShader(Tree.assets.files.shaders.soft_uniform_noise)
    love.graphics.rectangle("fill", self.bounds.x, self.bounds.y, self.bounds.width, self.bounds.height)
    love.graphics.setShader()

    --- закраска пустой части
    love.graphics.setColor(0.05, 0.05, 0.05)
    love.graphics.setBlendMode("multiply", "premultiplied")
    love.graphics.rectangle("fill", self.bounds.x + valueWidth, self.bounds.y, emptyWidth,
        self.bounds.height)
    love.graphics.setBlendMode("alpha")

    --- закраска значимой части её цветом
    love.graphics.setColor(self.color.r, self.color.g, self.color.b)
    love.graphics.setBlendMode("multiply", "premultiplied")
    love.graphics.rectangle("fill", self.bounds.x, self.bounds.y, valueWidth,
        self.bounds.height)
    love.graphics.setBlendMode("alpha")

    --- мерки
    love.graphics.setColor(38 / 255, 50 / 255, 56 / 255)
    if self.useDividers then
        local count = self.maxValue - 1
        local measureWidth = self.bounds.width / self.maxValue

        for i = 1, count, 1 do
            love.graphics.line(self.bounds.x + i * measureWidth, self.bounds.y, self.bounds.x + i * measureWidth,
                self.bounds.y + self.bounds.height)
        end
    end


    love.graphics.setColor(1, 1, 1)
    --- текст поверх
    if self.drawText then
        love.graphics.printf(tostring(self.value) .. "/" .. tostring(self.maxValue), self.bounds.x,
            self.bounds.y, self.bounds.width, "center")
    end

    self:drawBorder("inner")

    self:drawGradientOverlay()
end

--- @class BottomBars : UIElement
--- @field hpBar BarElement
--- @field manaBar BarElement
local bottomBars = setmetatable({}, Element)
bottomBars.__index = bottomBars;

--- @param cid Id
function bottomBars.new(cid)
    local t = setmetatable({}, bottomBars)

    t.hpBar =
        barElement:new {
            getter = function()
                local char = Tree.level.characters[cid]
                return char:try(Tree.behaviors.stats, function(stats)
                    return stats.hp or 0
                end)
            end,
            color = Color { r = 130 / 255, g = 8 / 255, b = 8 / 255 },
            drawText = true,
            maxValue = 20
        }

    t.manaBar =
        barElement:new {
            getter = function()
                local char = Tree.level.characters[cid]
                return char:try(Tree.behaviors.stats, function(stats)
                    return stats.mana or 0
                end)
            end,
            color = Color { r = 51 / 255, g = 105 / 255, b = 30 / 255 },
            useDividers = true,
            maxValue = 10
        }


    return t
end

function bottomBars:update(dt)
    local height = 16
    local margin = 2

    self.bounds.height = height
    self.bounds.y = self.bounds.y - height

    self.hpBar.bounds = Rect {
        width = -2 * margin + self.bounds.width / 2,
        height = height - margin,
        x = self.bounds.x + margin,
        y = self.bounds.y + margin
    }

    self.manaBar.bounds = Rect {
        width = -2 * margin + self.bounds.width / 2,
        height = height - margin,
        x = self.bounds.x + margin + self.bounds.width / 2,
        y = self.bounds.y + margin
    }

    self.hpBar:update(dt)
    self.manaBar:update(dt)
end

function bottomBars:draw()
    -- шум
    love.graphics.setShader(Tree.assets.files.shaders.soft_uniform_noise)
    love.graphics.rectangle("fill", self.bounds.x, self.bounds.y, self.bounds.width, self.bounds.height)
    love.graphics.setShader()

    love.graphics.setColor(38 / 255, 50 / 255, 56 / 255)
    love.graphics.setBlendMode("multiply", "premultiplied")
    love.graphics.rectangle("fill", self.bounds.x, self.bounds.y, self.bounds.width, self.bounds.height)
    love.graphics.setBlendMode("alpha")

    self.hpBar:draw()
    self.manaBar:draw()
end

--- @class CharacterPanel : UIElement
--- @field animationNode AnimationNode
--- @field state "show" | "idle" | "hide"
--- @field skillRow SkillRow
--- @field bars BottomBars
local characterPanel = setmetatable({}, Element)
characterPanel.__index = characterPanel

function characterPanel.new(characterId)
    local t = {}
    t.state = "show"
    t.skillRow = SkillRow(characterId)
    t.bars = bottomBars.new(characterId)
    return setmetatable(t, characterPanel)
end

function characterPanel:show()
    AnimationNode {
        function(animationNode)
            if self.animationNode then self.animationNode:finish() end
            self.animationNode = animationNode
            self.state = "show"
        end,
        duration = 300,
        onEnd = function()
            self.state = "idle"
        end,
        easing = easing.easeOutCubic
    }:run()
end

function characterPanel:hide()
    AnimationNode {
        function(animationNode)
            if self.animationNode then self.animationNode:finish() end
            self.animationNode = animationNode
            self.state = "hide"
        end,
        duration = 300,
        easing = easing.easeOutCubic
    }:run()
end

--- @type love.Canvas
local characterPanelCanvas;

function characterPanel:update(dt)
    if self.animationNode then self.animationNode:update(dt) end
    self.skillRow:update(dt)
    self.bars.bounds = Rect {
        width = self.skillRow.bounds.width,
        x = self.skillRow.bounds.x,
        y = self.skillRow.bounds.y
    }
    self.bars:update(dt)

    self.bounds = Rect {
        x = self.bars.bounds.x,
        y = self.bars.bounds.y,
        width = self.bars.bounds.width,
        height = self.bars.bounds.height + self.skillRow.bounds.height
    }

    if not characterPanelCanvas then
        characterPanelCanvas = love.graphics.newCanvas(self.bounds.width, self.bounds.height)
    end

    --- анимация появления
    local alpha = 1
    if self.state == "show" then
        alpha = self.animationNode:getValue()
    elseif self.state == "hide" then
        alpha = 1 - self.animationNode:getValue()
    end
    local revealShader = Tree.assets.files.shaders.reveal
    revealShader:send("t", alpha)
end

function characterPanel:draw()
    self.skillRow:draw()

    --- @TODO: переписать этот ужас с жонглированием координатами, а то слишком хардкод (skillRow рисуется относительно нуля и не закрывает канвас)
    love.graphics.push()
    local canvas = love.graphics.getCanvas()
    love.graphics.translate(0, self.bars.bounds.height)
    love.graphics.setCanvas(characterPanelCanvas)
    love.graphics.clear()
    love.graphics.draw(canvas)
    love.graphics.pop()

    love.graphics.push()
    love.graphics.translate(-self.bounds.x, -self.bounds.y)
    self.bars:draw()
    self:drawBorder("outer")
    love.graphics.pop()

    --- рисуем текстуру шейдером появления
    love.graphics.setCanvas()
    love.graphics.setShader(Tree.assets.files.shaders.reveal)
    love.graphics.setColor(1, 1, 1, 1)

    love.graphics.push()
    love.graphics.translate(self.bounds.x, self.bounds.y)
    love.graphics.draw(characterPanelCanvas)
    love.graphics.setColor(1, 1, 1)
    love.graphics.pop()
    love.graphics.setShader()
end

-----------------------------------
local layout = {}
function layout:update(dt)
    local cid = Tree.level.selector:selected()
    if cid then
        self.characterPanel = characterPanel.new(cid)
        self.characterPanel:show()
    elseif Tree.level.selector:deselected() then
        self.characterPanel:hide()
    end
    if self.characterPanel then self.characterPanel:update(dt) end
end

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

return layout