local Tilemap = require("tilemap")
local Entity = require("entity")
local Player = require("player")
local Camera = require("camera")
local Textbox = require("textbox")
local Enemy = require("enemy")

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.spikes = {}
    self.textTriggers = {}
    self.refractionCanvas = nil
    self.liquidShader = nil
    self.activeSplashes = {}
    self.camera = nil
    self.groundContacts = {}
    self.waterContacts = {}
    self.contactCounts = {}
    self.contactEntity = {}
    self.contactKind = {}
    self.pendingPlayerDeath = nil
    self.playerTextbox = Textbox:new()
    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

    local ok, shader = pcall(love.graphics.newShader, "shaders/missing_texture.glsl")
    self.missingShader = ok and shader or nil
    if not ok then
        print("Warning: missing_texture.glsl not loaded, using fallback (no missing texture)")
    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)
        elseif entityType == "Enemy" then
            local e = Enemy.new(spawn.x, spawn.y, spawn.width, spawn.height)
            e:setWorldContext(self)
            e:setPropertiesFromOptions({ properties = spawn.properties or {}, name = spawn.name, type = spawn.type })
            table.insert(self.entities, e)
        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

    for _, spike in ipairs(self.tilemap:getEntitiesSpikes()) do
        spike:setWorldPhysics(self.physicsWorld)
        table.insert(self.spikes, spike)
        table.insert(self.entities, spike)
    end

    for _, textTrigger in ipairs(self.tilemap:getEntitiesTextTriggers()) do
        textTrigger:setWorldPhysics(self.physicsWorld)
        table.insert(self.textTriggers, textTrigger)
        table.insert(self.entities, textTrigger)
    end

    local ok, shader = pcall(love.graphics.newShader, "shaders/liquid.glsl")
    self.liquidShader = ok and shader or nil
    if not self.liquidShader then
        print("Warning: liquid.glsl not loaded, using fallback (no refraction)")
    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:_isHazard(ud)
    return type(ud) == "table" and (ud.isSpike or ud.isEnemy)
end

function World:handleTextTrigger(trigger, player)
    if trigger and player and trigger.isTextTrigger and self:_isPlayerLike(player) then
        trigger:trigger(self, player)
    end
end

function World:_onBeginContact(udA, udB, nx, ny, contact)
    if type(udA) == "table" and udA.isTextTrigger then
        self:handleTextTrigger(udA, udB)
    elseif type(udB) == "table" and udB.isTextTrigger then
        self:handleTextTrigger(udB, udA)
    end

    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 centerY = waterData.water.y or 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
            centerY = (y1 + (y2 or y1)) * 0.5
        elseif entity and entity.body then
            centerX = entity.body:getX()
            centerY = entity.body:getY()
        else
            centerX = waterData.water.x or 0
        end
        waterData.water:splash(centerX, 2)
        table.insert(self.activeSplashes, { x = centerX, y = centerY, t = 0 })
    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

    local playerEntity, hazardNx, hazardNy
    if self:_isHazard(udA) and self:_isPlayerLike(udB) then
        playerEntity = udB
        hazardNx, hazardNy = nx, ny
    elseif self:_isHazard(udB) and self:_isPlayerLike(udA) then
        playerEntity = udA
        hazardNx, hazardNy = -nx, -ny
    end
    if playerEntity and not playerEntity.isDead then
        self.pendingPlayerDeath = { nx = hazardNx, ny = hazardNy }
    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

function World:isTileSolidAtPixel(x, y)
    local groundLayer = self.tilemap:getGroundLayer()
    if not groundLayer or not groundLayer.data then return false end
    local dims = self.tilemap:getLayerTileDimensions("ground")
    local tw = dims.tilewidth or self.tilemap:getTileWidth()
    local th = dims.tileheight or self.tilemap:getTileHeight()
    local mapW = self.mapData.width or 0
    local mapH = self.mapData.height or 0
    local col = math.floor(x / tw)
    local row = math.floor(y / th)
    if col < 0 or col >= mapW or row < 0 or row >= mapH then return false end
    local idx = row * mapW + col + 1
    local gid = groundLayer.data[idx]
    return gid and gid ~= 0
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

    local hasLiquid = (#self.liquidPolygons > 0 or #self.liquidSurfaces > 0)
    local useRefraction = hasLiquid and self.liquidShader

    if useRefraction then
        local mainCanvas = love.graphics.getCanvas()
        local cw, ch = mainCanvas:getDimensions()
        if not self.refractionCanvas or self.refractionCanvas:getWidth() ~= cw or self.refractionCanvas:getHeight() ~= ch then
            if self.refractionCanvas then self.refractionCanvas:release() end
            self.refractionCanvas = love.graphics.newCanvas(cw, ch)
            self.refractionCanvas:setFilter("linear", "linear")
        end

        love.graphics.push()
        love.graphics.setCanvas(self.refractionCanvas)
        love.graphics.clear(0, 0, 0, 1)
        drawTileLayer(self.tilemap:getFargroundLayer(), mapTileW, mapTileH, tileGidInfo, viewMinX, viewMinY, viewMaxX, viewMaxY)
        drawTileLayer(self.tilemap:getDecorationBackgroundLayer(), mapTileW, mapTileH, tileGidInfo, viewMinX, viewMinY, viewMaxX, viewMaxY)
        drawTileLayer(self.tilemap:getBackgroundLayer(), mapTileW, mapTileH, tileGidInfo, viewMinX, viewMinY, viewMaxX, viewMaxY)
        drawTileLayer(self.tilemap:getGroundLayer(), mapTileW, mapTileH, tileGidInfo, viewMinX, viewMinY, viewMaxX, viewMaxY)
        for _, spike in ipairs(self.tilemap:getEntitiesSpikes()) do
            spike:draw()
        end
        for _, e in ipairs(self.entities) do
            if e.draw then e:draw() else World.drawEntityDefault(self, e) end
        end
        drawTileLayer(self.tilemap:getForegroundLayer(), mapTileW, mapTileH, tileGidInfo, viewMinX, viewMinY, viewMaxX, viewMaxY)
        drawTileLayer(self.tilemap:getDecorationForegroundLayer(), mapTileW, mapTileH, tileGidInfo, viewMinX, viewMinY, viewMaxX, viewMaxY)
        love.graphics.setCanvas(mainCanvas)
        love.graphics.pop()

        love.graphics.push()
        love.graphics.origin()
        love.graphics.draw(self.refractionCanvas, 0, 0)
        love.graphics.pop()

        local splash = self.activeSplashes[#self.activeSplashes]
        local splashCenterX, splashCenterY = 0.5, 0.5
        local splashTime = 0
        if splash and self.camera then
            local snapX = math.floor(self.camera.x)
            local snapY = math.floor(self.camera.y)
            local scale = self.camera._lastScale or 2
            splashCenterX = ((splash.x - snapX) * scale) / cw
            splashCenterY = ((splash.y - snapY) * scale) / ch
            splashTime = splash.t
        end

        self.liquidShader:send("scene", self.refractionCanvas)
        self.liquidShader:send("time", love.timer.getTime())
        self.liquidShader:send("resolution", { cw, ch })
        self.liquidShader:send("splashCenter", { splashCenterX, splashCenterY })
        self.liquidShader:send("splashTime", splashTime)
        love.graphics.setShader(self.liquidShader)

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

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

        love.graphics.setShader()
    else
        drawTileLayer(self.tilemap:getBackgroundLayer(), mapTileW, mapTileH, tileGidInfo, viewMinX, viewMinY, viewMaxX, viewMaxY)
        drawTileLayer(self.tilemap:getDecorationBackgroundLayer(), mapTileW, mapTileH, tileGidInfo, viewMinX, viewMinY, viewMaxX, viewMaxY)
        drawTileLayer(self.tilemap:getGroundLayer(), mapTileW, mapTileH, tileGidInfo, viewMinX, viewMinY, viewMaxX, viewMaxY)
        drawTileLayer(self.tilemap:getFargroundLayer(), mapTileW, mapTileH, tileGidInfo, viewMinX, viewMinY, viewMaxX, viewMaxY)
        drawTileLayer(self.tilemap:getDecorationBackgroundLayer(), 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
                end
            end
        end

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

    for _, surface in ipairs(self.liquidSurfaces) do
        if surface.drawLine then
            surface:drawLine()
        end
    end
    love.graphics.setColor(1, 1, 1, 1)

    if not useRefraction then
        for _, e in ipairs(self.entities) do
            print(e)
            if e.draw then e:draw() else World.drawEntityDefault(self, e) end
        end
        drawTileLayer(self.tilemap:getForegroundLayer(), mapTileW, mapTileH, tileGidInfo, viewMinX, viewMinY, viewMaxX, viewMaxY)
        drawTileLayer(self.tilemap:getDecorationForegroundLayer(), mapTileW, mapTileH, tileGidInfo, viewMinX, viewMinY, viewMaxX, viewMaxY)
    end

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

    self.playerTextbox:draw()
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(self, entity)
    love.graphics.setColor(0.2, 0.6, 1, 1)
    if entity.isPlayer then
        love.graphics.setColor(1, 0.3, 0.2, 1)
    end
    if self.missingShader then
        love.graphics.setShader(self.missingShader)
        love.graphics.draw(entity.texture, math.floor(entity.x), math.floor(entity.y))
        love.graphics.setShader()
    else
        love.graphics.rectangle("fill", math.floor(entity.x), math.floor(entity.y), entity.width, entity.height)
    end
    love.graphics.setColor(1, 1, 1, 1)
end

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

    if self.pendingPlayerDeath and self.player then
        self.player:die(self.pendingPlayerDeath.nx, self.pendingPlayerDeath.ny)
        self.pendingPlayerDeath = nil
    end

    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
        if self.player.isInLiquid and not self.player.wasInLiquid then
            local px = self.player.x + (self.player.width or 16) / 2
            local py = self.player.y - 20
            --self.playerTextbox:show("Entered water!", { px, py, "center" }, "write", { life = 2, fontSize = 9, centeredText = true, wrapToFit = true })
        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

    for _, spike in ipairs(self.tilemap:getEntitiesSpikes()) do
        if spike.update then spike:update(dt) end
    end

    for i = #self.activeSplashes, 1, -1 do
        self.activeSplashes[i].t = self.activeSplashes[i].t + dt * 2
        if self.activeSplashes[i].t >= 1 then
            table.remove(self.activeSplashes, i)
        end
    end
    if #self.activeSplashes > 4 then
        for _ = 1, #self.activeSplashes - 4 do
            table.remove(self.activeSplashes, 1)
        end
    end

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

    if self.playerTextbox.active and self.player then
        self.playerTextbox.x = self.player.x + (self.player.width or 16) / 2
        self.playerTextbox.y = self.player.y - 20
    end
    self.playerTextbox:update(dt)
end

return World