--[[
Illarion Server

This program is free software: you can redistribute it and/or modify it under
the terms of the GNU Affero General Public License as published by the Free
Software Foundation, either version 3 of the License, or (at your option) any
later version.

This program 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 Affero General Public License for more
details.

You should have received a copy of the GNU Affero General Public License along
with this program.  If not, see <http://www.gnu.org/licenses/>.
]]

local common = require("base.common")
local character = require("base.character")
local M = {}

local function HitVictims(Posi,Hitpoints,CenterPos)
    if world:isCharacterOnField(Posi) then
        local explosionVictim = world:getCharacterOnField(Posi)

        if (explosionVictim:getType() == 2) then --dont touch npcs
            return
        end

        local Distance = explosionVictim:distanceMetricToPosition(CenterPos)
        local Diffx = CenterPos.x - explosionVictim.pos.x
        local Diffy = CenterPos.y - explosionVictim.pos.y
        if (Distance == 1) then
            Diffx = 4*Diffx
            Diffy = 4*Diffy
        elseif (Distance == 2) then
            Diffx = 2*Diffx
            Diffy = 2*Diffy
        end
        local posX = explosionVictim.pos.x - Diffx
        local posY = explosionVictim.pos.y - Diffy

        local listOfStuff = world:LoS(explosionVictim.pos, position(posX,posY,explosionVictim.pos.z))

        if listOfStuff ~= nil then
            local minDistance = explosionVictim:distanceMetricToPosition(position(posX,posY,explosionVictim.pos.z))

            for _, listEntry in pairs(listOfStuff) do
                local itemPos = listEntry.OBJECT.pos
                local field = world:getField(itemPos)
                local tempX = posX
                local tempY = posY
                -- something not passable is in the way, recalculate position
                if not field:isPassable() then

                    local phi = common.GetPhi(explosionVictim.pos, itemPos)
                    if (phi < math.pi / 8) then
                        tempX = itemPos.x - 1
                    elseif (phi < 3 * math.pi / 8) then
                        tempX = itemPos.x - 1
                        tempY = itemPos.y - 1
                    elseif (phi < 5 * math.pi / 8) then
                        tempY = itemPos.y - 1
                    elseif (phi < 7 * math.pi / 8) then
                        tempX = itemPos.x + 1
                        tempY = itemPos.y - 1
                    elseif (phi < 9 * math.pi / 8) then
                        tempX = itemPos.x + 1
                    elseif (phi < 11 * math.pi / 8) then
                        tempX = itemPos.x + 1
                        tempY = itemPos.y + 1
                    elseif (phi < 13 * math.pi / 8) then
                        tempY = itemPos.y + 1
                    elseif (phi < 15 * math.pi / 8) then
                        tempX = itemPos.x - 1
                        tempY = itemPos.y + 1
                    else
                        tempX = itemPos.x - 1
                    end

                    local tempDistance = explosionVictim:distanceMetricToPosition(position(tempX,tempY,explosionVictim.pos.z))
                    if tempDistance < minDistance then
                        minDistance = tempDistance
                        posX = tempX
                        posY = tempY
                    end
                end
            end
        end

        explosionVictim:warp(position(posX,posY,explosionVictim.pos.z))
        common.InformNLS(explosionVictim,
            "Getroffen von der Detonation wirst du davon geschleudert.",
            "Hit by the detonation, you get thrown away.")
        character.ChangeHP(explosionVictim, -Hitpoints)

    end
end

local function CreateExplosionCircle(HitPos,gfxid,Damage,CenterPos,setFlames)

    world:gfx(gfxid,HitPos)
    HitVictims(HitPos,Damage,CenterPos)

    if setFlames then
        if (math.random(1,5)==1) then
            local field = world:getField(HitPos)
            if field ~= nil and field:isPassable() then
                world:createItemFromId(359,1,HitPos,true,math.random(200,600),nil)
            end
        end
    end
end

--[[
    CreateExplosion
    Provide an explosion that also throws characters away, in a radios of 3 fields
    @param integer - Center of the explosion
]]
function M.CreateExplosion(CenterPos)
    local function CreateOuterCircle(HitPos)
        CreateExplosionCircle(HitPos, 1,250,CenterPos,false)
        return true
    end
    local function CreateMiddleCircle(HitPos)
        CreateExplosionCircle(HitPos,9,750,CenterPos,true)
        return true
    end
    local function CreateInnerCircle(HitPos)
        CreateExplosionCircle(HitPos, 44,1000,CenterPos,true)
        return true
    end

    common.CreateCircle(CenterPos, 3, CreateOuterCircle)
    common.CreateCircle(CenterPos, 2, CreateMiddleCircle)
    common.CreateCircle(CenterPos, 1, CreateInnerCircle)
    world:gfx(36,CenterPos)
    world:makeSound(5,CenterPos)
end

return M