-- 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")
local UnitGroup = types.CreateClass("UnitGroup")
types.UnitGroup = UnitGroup

local function RoleValue(role)
    if role == "TANK" then
        return 0
    elseif role == "HEALER" then
        return 1
    elseif role == "DAMAGER" then
        return 2
    else
        return 3
    end
end

local function UnitFrameDefaultCompare(lhs, rhs)
    -- visible < invisible
    if lhs.secureFrame:IsShown() ~= rhs.secureFrame:IsShown() then
        return lhs.secureFrame:IsShown()
    end

    local lunit, runit = lhs.unit, rhs.unit

    -- players < non-players
    local player = UnitIsPlayer(lunit)
    if UnitIsPlayer(lunit) ~= UnitIsPlayer(runit) then
        return player
    end

    if player then
        -- you < others
        if UnitIsUnit(lunit, "player") ~= UnitIsUnit(runit, "player") then
            return UnitIsUnit(lunit, "player")
        end

        -- tank < healer < damage < ?
        local lrole = RoleValue(UnitGroupRolesAssigned(lunit))
        local rrole = RoleValue(UnitGroupRolesAssigned(runit))

        if lrole ~= rrole then
            return lrole < rrole
        end
    end

    return lunit < runit
end

function UnitGroup:Init(left, top, width, height)
    self.width = width
    self.height = height
    self.top = top
    self.left = left
    self.units = {}
    self.sortAfterCombat = false
    self:RegisterEvents()
end

function UnitGroup:RegisterEvents()
    local frame = CreateFrame("Frame")
    self.frame = frame

    frame:SetScript("OnEvent", function(frame, event, ...)
        self[event](self, ...)
    end)

    frame:RegisterEvent("GROUP_ROSTER_UPDATE")
    frame:RegisterEvent("PLAYER_REGEN_ENABLED")
    frame:RegisterEvent("PLAYER_ENTERING_WORLD")
end

function UnitGroup:GROUP_ROSTER_UPDATE()
    self:OnRosterUpdate()
end

function UnitGroup:PLAYER_ENTERING_WORLD()
    self:OnRosterUpdate()
end

function UnitGroup:PLAYER_REGEN_ENABLED()
    self:OnLeaveCombat()
end

function UnitGroup:OnLeaveCombat()
    if self.sortAfterCombat then
        self:Sort()
        self.sortAfterCombat = false
    end
end

function UnitGroup:OnRosterUpdate()
    if InCombatLockdown() then
        self.sortAfterCombat = true
    else
        self:Sort()
    end
end

function UnitGroup:AddUnitFrame(unit)
    table.insert(self.units, unit)
end

function UnitGroup:Sort()
    table.sort(self.units, UnitFrameDefaultCompare)
    local left, top, width, height = self.left, self.top, self.width, self.height
    local maxFrameIndex = #self.units
    for y = 0, 5 do
        for x = 0, 4 do
            local num = y * 5 + x + 1
            if num > maxFrameIndex then
                return
            end
            local frame = self.units[num]
            frame:SetPosition(left + (x - 2) * width, top - y * height)
        end
    end
end