-- Copyright 2023 <omicron.me@protonmail.com>
--
-- This file is part of Omicron Frames
-- 
-- Omicron Frames is free software: you can redistribute it and/or modify it
-- under the terms of the GNU General Public License as published by the Free
-- Software Foundation, either version 3 of the License, or (at your option)
-- any later version.
--
-- Omicron Frames is distributed in the hope that it will be useful, but
-- WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
-- or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
-- more details.
--
-- You should have received a copy of the GNU General Public License along with
-- Omicron Frames. If not, see <https://www.gnu.org/licenses/>. 
local omi = select(2, ...)
local types = omi.GetModule("types")

---
-- Trigger objects provide a link between indicators and some data source. They
-- can pass data from the data source into the trigger. This is just a
-- supertype for all indicators and should not be constructed on its own. It
-- has no functionality other than providing default implementations that do
-- nothing.
types.Trigger = types.CreateClass("Trigger")
local Trigger = types.Trigger


-- Initialize a new Trigger object
-- indicator:
--      The indicator that gets activated by this trigger.
function Trigger:Init(indicator)
    self.indicator = indicator
end

-- Returns whether or not the trigger is active
function Trigger:IsActive()
    return false
end

-- Reset the trigger to the default state. Deactivates the indicator if it is
-- active when Reset is called.
function Trigger:Reset()
end


---
-- AuraTrigger is a trigger that can be attached to AuraList as datasource
types.AuraTrigger = types.CreateClass("AuraTrigger", Trigger)
local AuraTrigger = types.AuraTrigger

--- Initialize a new AuraTrigger object
-- indicator
--      Indicator that gets controlled by this trigger.
-- spellId
--      Spell id to trigger on
-- own
--      Only trigger on auras by the player
-- requiredCount=1
--      Number of aura applications to activate trigger
-- invert=false
--      Whether to invert trigger activation
function AuraTrigger:Init(indicator, spellId, own, requiredCount, invert)
    Trigger.Init(self, indicator)
    self.spellId = spellId
    self.requiredCount = requiredCount or 1
    self.own = own
    self.count = 0
    self.invert = invert or false
end

--- See Trigger:Reset
function AuraTrigger:Reset()
    local before = self:IsActive()
    self.count = 0
    local after = self:IsActive()
    if not before and after then
        self.indicator:Show()
    elseif before and not after then
        self.indicator:Hide()
    end
end

--- Return true if the aura matches the trigger
-- aura:
--      Must be a valid UnitAuraInfo structure.
function AuraTrigger:IsMatching(aura)
    if aura.spellId ~= aura.spellId then
        return false
    end
    if self.own and aura.sourceUnit ~= "player" then
        return false
    end
    return true
end

--- Inform the trigger about an added aura
-- aura:
--      Must be a valid UnitAuraInfo
function AuraTrigger:AddAura(aura)
    if not self:IsMatching(aura) then
        return
    end
    self.count = self.count + 1

    -- Be mindful, this works only if count always changes by 1.
    if self.count == self.requiredCount then
        if self.invert then
            self.indicator:Hide()
        else
            self.indicator:Show()
        end
    end
end

--- Inform the trigger about an updated aura
-- before:
--      Must be a valid UnitAuraInfo for the aura before the update
-- after:
--      Must be a valid UnitAuraInfo for the aura after the update
function AuraTrigger:UpdateAura(before, after)
    --
end

--- Inform the trigger about an aura that got removed
-- aura:
--      Must be a valid UnitAuraInfo for the aura before it got removed
function AuraTrigger:RemoveAura(aura)
    if not self:IsMatching(aura) then
        return
    end
    self.count = self.count - 1
    -- Be mindful, this works only if count always changes by 1.
    if self.count == self.requiredCount - 1 then
        if self.invert then
            self.indicator:Show()
        else
            self.indicator:Hide()
        end
    end
end

--- Returns true if the trigger is active, false otherwise
function AuraTrigger:IsActive()
    if self.invert then
        return self.count < self.requiredCount
    else
        return self.count >= self.requiredCount
    end
end