local Tilemap = require("tilemap")
local Entity = require("entity")
local Player = require("player")
local Camera = require("camera")

local World = {}
World.__index = World

local GRAVITY = 9.81 * 64
local PHYSICS_DT = 1 / 60

function World:new()
    local self = setmetatable({}, World)
    self.physicsWorld = nil
    self.tilemap = nil
    self.mapData = nil
    self.groundEntities = {}
    self.player = nil
    self.enemies = {}
    self.entities = {}
    self.liquidPolygons = {}
    self.liquidSurfaces = {}
    self.liquidSurfaceFixtures = {}
    self.camera = nil
    self.groundContacts = {}
    self.waterContacts = {}
    self.contactCounts = {}
    self.contactEntity = {}
    self.contactKind = {}
    return self
end

function World:load(mapPath, tilesets)
    if self.physicsWorld then
        self.groundEntities = {}
    end
    self.physicsWorld = love.physics.newWorld(0, GRAVITY)
    self.physicsWorld:setCallbacks(
        function(fa, fb, contact)
            local udA, udB = fa:getUserData(), fb:getUserData()
            local nx, ny = contact:getNormal()
            self:_onBeginContact(udA, udB, nx, ny, contact)
        end,
        function(fa, fb, contact)
            local udA, udB = fa:getUserData(), fb:getUserData()
            self:_onEndContact(udA, udB, contact)
        end
    )

    self.tilemap = Tilemap:new(mapPath, tilesets)
    self.mapData = self.tilemap:getMapData()
    if not self.mapData then
        error("World:load - no map data from " .. tostring(mapPath))
    end

    local groundDims = self.tilemap:getLayerTileDimensions("ground")
    local tileWidth = groundDims.tilewidth
    local tileHeight = groundDims.tileheight

    local groundLayer = self.tilemap:getGroundLayer()
    if groundLayer and groundLayer.data then
        local mapW = self.mapData.width or 0
        local mapH = self.mapData.height or 0
        local data = groundLayer.data

        local solid = {}
        for row = 0, mapH - 1 do
            solid[row] = {}
            for col = 0, mapW - 1 do
                local idx = row * mapW + col + 1
                local gid = data[idx]
                solid[row][col] = (gid and gid ~= 0)
            end
        end

        for row = 0, mapH - 1 do
            local col = 0
            while col < mapW do
                if solid[row][col] then
                    local startCol = col
                    while col < mapW and solid[row][col] do
                        col = col + 1
                    end
                    local stripWidth = (col - startCol) * tileWidth
                    local x = startCol * tileWidth
                    local y = row * tileHeight
                    local strip = Entity:new(x, y, stripWidth, tileHeight)
                    strip:enablePhysics(self.physicsWorld, "static")
                    strip.fixture:setUserData("ground")
                    table.insert(self.groundEntities, strip)
                else
                    col = col + 1
                end
            end
        end
    end

    self.player = nil
    self.enemies = {}
    self.entities = {}
    self.liquidPolygons = self.tilemap:getEntitiesLiquidPolygons() or {}
    self.liquidSurfaces = self.tilemap:getEntitiesLiquidSurfaces() or {}
    self.liquidSurfaceFixtures = {}
    local spawns = self.tilemap:getEntitiesSpawns()
    for _, spawn in ipairs(spawns) do
        local entityType = spawn:get("entity", "")
        if entityType == "Player" and not self.player then
            self.player = Player.new(self.physicsWorld, spawn.x, spawn.y)
            self.player.isPlayer = true
            table.insert(self.entities, self.player)
        else
            local e = Entity:new(spawn.x, spawn.y, spawn.width, spawn.height)
            e:setPropertiesFromOptions({ properties = spawn.properties or {}, name = spawn.name, type = spawn.type })
            if entityType ~= "" then
                table.insert(self.enemies, e)
            end
            table.insert(self.entities, e)
        end
    end

    for _, surface in ipairs(self.liquidSurfaces) do
        local cx = (surface.x or 0) + (surface.width or 0) * 0.5
        local cy = (surface.y or 0) + (surface.height or 0) * 0.5
        local body = love.physics.newBody(self.physicsWorld, cx, cy, "static")
        local shape = love.physics.newRectangleShape(surface.width or 0, surface.height or 0)
        local fixture = love.physics.newFixture(body, shape, 1)
        fixture:setSensor(true)
        fixture:setUserData({ type = "water", water = surface })
        table.insert(self.liquidSurfaceFixtures, { body = body, fixture = fixture })
    end

end

function World:_addContact(entity, kind)
    self.contactCounts[entity] = self.contactCounts[entity] or { floor = 0, wall = 0, ceiling = 0 }
    self.contactCounts[entity][kind] = (self.contactCounts[entity][kind] or 0) + 1
    entity.contact = entity.contact or { floor = 0, wall = 0, ceiling = 0 }
    entity.contact[kind] = 1
end

function World:_removeContact(entity, kind)
    self.contactCounts[entity] = self.contactCounts[entity] or { floor = 0, wall = 0, ceiling = 0 }
    self.contactCounts[entity][kind] = math.max(0, (self.contactCounts[entity][kind] or 0) - 1)
    entity.contact = entity.contact or { floor = 0, wall = 0, ceiling = 0 }
    entity.contact[kind] = (self.contactCounts[entity][kind] > 0) and 1 or 0
end

function World:_normalToContactType(nx, ny)
    local ax, ay = math.abs(nx), math.abs(ny)
    if ay >= ax then
        if ny < -0.3 then return "floor" end
        if ny > 0.3 then return "ceiling" end
    else
        if ax > 0.3 then return "wall" end
    end
    return nil
end

function World:_isTrackedEntity(ud)
    return type(ud) == "table" and (ud.body ~= nil or ud.x ~= nil)
end

function World:_isPlayerLike(ud)
    return type(ud) == "table" and ud.jump ~= nil
end

function World:_onBeginContact(udA, udB, nx, ny, contact)
    if udA == "ground" and self:_isTrackedEntity(udB) then
        local kind = self:_normalToContactType(nx, ny)
        if kind then
            self:_addContact(udB, kind)
            self.contactEntity[contact] = udB
            self.contactKind[contact] = kind
        end
        self.groundContacts[udB] = (self.groundContacts[udB] or 0) + 1
        if self:_isPlayerLike(udB) then udB.grounded = true end
    elseif udB == "ground" and self:_isTrackedEntity(udA) then
        local kind = self:_normalToContactType(-nx, -ny)
        if kind then
            self:_addContact(udA, kind)
            self.contactEntity[contact] = udA
            self.contactKind[contact] = kind
        end
        self.groundContacts[udA] = (self.groundContacts[udA] or 0) + 1
        if self:_isPlayerLike(udA) then udA.grounded = true end
    end

    local function doWaterSplash(waterData, entity)
        if not (waterData and waterData.water and waterData.water.splash) then return end
        local centerX = 0
        local ok, x1, y1, x2, y2 = pcall(function() return contact:getPositions() end)
        if ok and x1 then
            centerX = (x1 + (x2 or x1)) * 0.5
        elseif entity and entity.body then
            centerX = entity.body:getX()
        else
            centerX = waterData.water.x or 0
        end
        waterData.water:splash(centerX, 2)
    end

    if type(udA) == "table" and udA.type == "water" and self:_isTrackedEntity(udB) then
        self.waterContacts[udB] = (self.waterContacts[udB] or 0) + 1
        doWaterSplash(udA, udB)
    elseif type(udB) == "table" and udB.type == "water" and self:_isTrackedEntity(udA) then
        self.waterContacts[udA] = (self.waterContacts[udA] or 0) + 1
        doWaterSplash(udB, udA)
    end
end

function World:_onEndContact(udA, udB, contact)
    local ent = self.contactEntity[contact]
    local kind = ent and self.contactKind[contact]
    if ent and kind then
        self:_removeContact(ent, kind)
        self.contactEntity[contact] = nil
        self.contactKind[contact] = nil
    end
    if type(udA) == "table" and udA.type == "water" and self:_isTrackedEntity(udB) then
        self.waterContacts[udB] = math.max(0, (self.waterContacts[udB] or 0) - 1)
    elseif type(udB) == "table" and udB.type == "water" and self:_isTrackedEntity(udA) then
        self.waterContacts[udA] = math.max(0, (self.waterContacts[udA] or 0) - 1)
    end
    if udA == "ground" and self:_isTrackedEntity(udB) then
        self.groundContacts[udB] = math.max(0, (self.groundContacts[udB] or 0) - 1)
        if self:_isPlayerLike(udB) then
            udB.grounded = (self.groundContacts[udB] or 0) > 0
        end
    elseif udB == "ground" and self:_isTrackedEntity(udA) then
        self.groundContacts[udA] = math.max(0, (self.groundContacts[udA] or 0) - 1)
        if self:_isPlayerLike(udA) then
            udA.grounded = (self.groundContacts[udA] or 0) > 0
        end
    end
end

function World:setCamera(camera)
    self.camera = camera
    self.camera:setLimits(self.tilemap:getCameraLimits())
end

function World:getPlayer()
    return self.player
end

function World:getPhysicsWorld()
    return self.physicsWorld
end

function World:getMapData()
    return self.mapData
end

local function drawTileLayer(layer, mapTileW, mapTileH, tileGidInfo, viewMinX, viewMinY, viewMaxX, viewMaxY)
    if not layer or not layer.visible or not layer.data then return end
    local w = layer.width or 0
    local h = layer.height or 0
    if w == 0 or h == 0 then return end

    local minCol, maxCol, minRow, maxRow
    if viewMinX and viewMaxX and viewMinY and viewMaxY then
        minCol = math.max(0, math.floor(viewMinX / mapTileW))
        maxCol = math.min(w - 1, math.floor(viewMaxX / mapTileW))
        minRow = math.max(0, math.floor(viewMinY / mapTileH))
        maxRow = math.min(h - 1, math.floor(viewMaxY / mapTileH))
    else
        minCol, maxCol = 0, w - 1
        minRow, maxRow = 0, h - 1
    end

    local batches = {}
    local fallbacks = {}
    local data = layer.data
    for ty = minRow, maxRow do
        for tx = minCol, maxCol do
            local idx = ty * w + tx + 1
            local gid = data[idx]
            if gid and gid ~= 0 then
                local x = tx * mapTileW
                local y = ty * mapTileH
                local info = tileGidInfo and tileGidInfo[gid]
                if info then
                    local img = info.image
                    batches[img] = batches[img] or {}
                    table.insert(batches[img], { quad = info.quad, x = x, y = y })
                else
                    table.insert(fallbacks, { x = x, y = y, gid = gid })
                end
            end
        end
    end

    for img, tiles in pairs(batches) do
        local batch = love.graphics.newSpriteBatch(img, #tiles, "static")
        for _, t in ipairs(tiles) do
            batch:add(t.quad, t.x, t.y)
        end
        love.graphics.draw(batch)
    end

    for _, t in ipairs(fallbacks) do
        local r = ((t.gid * 17) % 256) / 255
        local g = ((t.gid * 31 + 50) % 256) / 255
        local b = ((t.gid * 47 + 100) % 256) / 255
        love.graphics.setColor(r, g, b, 1)
        love.graphics.rectangle("fill", t.x, t.y, mapTileW, mapTileH)
        love.graphics.setColor(1, 1, 1, 1)
    end
end

function World:draw()
    local mapTileW = self.tilemap:getTileWidth()
    local mapTileH = self.tilemap:getTileHeight()
    local tileGidInfo = self.tilemap:getTileGidInfo()

    local viewMinX, viewMinY, viewMaxX, viewMaxY
    if self.camera then
        local cx, cy = self.camera.x, self.camera.y
        local cw = self.camera.width or 0
        local ch = self.camera.height or 0
        local pad = math.max(mapTileW, mapTileH) * 2
        viewMinX = cx - pad
        viewMinY = cy - pad
        viewMaxX = cx + cw + pad
        viewMaxY = cy + ch + pad
    end

    drawTileLayer(self.tilemap:getBackgroundLayer(), mapTileW, mapTileH, tileGidInfo, viewMinX, viewMinY, viewMaxX, viewMaxY)
    drawTileLayer(self.tilemap:getGroundLayer(), mapTileW, mapTileH, tileGidInfo, viewMinX, viewMinY, viewMaxX, viewMaxY)

    love.graphics.setColor(0.25, 0.5, 0.9, 0.6)

for _, liquid in ipairs(self.liquidPolygons) do
    if liquid.triangles then
        for _, tri in ipairs(liquid.triangles) do
            love.graphics.polygon("fill", tri)
        end
    end
end

love.graphics.setColor(1,1,1,1)

for _, surface in ipairs(self.liquidSurfaces) do
    if surface.draw then
        surface:draw()
    end
end

for _, p in ipairs(self.liquidPolygons) do
    love.graphics.circle("fill", p.x, p.y, 3)
end
    for _, e in ipairs(self.entities) do
        if e.draw then e:draw() else World.drawEntityDefault(e) end
    end

    if DEBUG then
        World.drawPhysicsBodyOutlines(self.entities)
        World.drawPhysicsBodyOutlines(self.groundEntities)
    end

    drawTileLayer(self.tilemap:getForegroundLayer(), mapTileW, mapTileH, tileGidInfo, viewMinX, viewMinY, viewMaxX, viewMaxY)
end

function World.drawPhysicsBodyOutlines(entityList)
    if not entityList then return end
    love.graphics.setColor(0, 1, 0, 1)
    for _, e in ipairs(entityList) do
        local body = e.body
        if body and e.physicsWidth and e.physicsHeight then
            local cx, cy = body:getX(), body:getY()
            local x = math.floor(cx - e.physicsWidth / 2)
            local y = math.floor(cy - e.physicsHeight / 2)
            love.graphics.rectangle("line", x, y, e.physicsWidth, e.physicsHeight)
        end
    end
    love.graphics.setColor(1, 1, 1, 1)
end

function World.drawEntityDefault(entity)
    love.graphics.setColor(0.2, 0.6, 1, 1)
    if entity.isPlayer then
        love.graphics.setColor(1, 0.3, 0.2, 1)
    end
    love.graphics.rectangle("fill", math.floor(entity.x), math.floor(entity.y), entity.width, entity.height)
    love.graphics.setColor(1, 1, 1, 1)
end

function World:update(dt)
    if not self.physicsWorld then return end
    self.physicsWorld:update(PHYSICS_DT)

    for _, e in ipairs(self.entities) do
        if e.body then
            e:syncFromPhysicsBody()
        end
    end

    if self.player then
        self.player.isInLiquid = false
        self.player.waterSurfaceContact = (self.waterContacts[self.player] or 0) > 0
        for _, liquid in ipairs(self.liquidPolygons) do
            if liquid:containsEntity(self.player) then self.player.isInLiquid = true break end
        end
    end


    for _, e in ipairs(self.entities) do
        if e.update then e:update(dt) end
    end

    for _, liquid in ipairs(self.liquidPolygons) do
        if liquid.update then liquid:update(dt) end
    end

    for _, surface in ipairs(self.liquidSurfaces) do
        if surface.update then surface:update(dt) end
    end

    if self.camera then
        self.camera:setTarget(self.player)
        self.camera:update(dt)
    end
end

return World