Move everything to src folder... it had to happen

src/matrix/kstate.js

@@ -0,0 +1,109 @@
+// @ts-check
+
+const assert = require("assert").strict
+const mixin = require("@cloudrac3r/mixin-deep")
+const {isDeepStrictEqual} = require("util")
+
+const passthrough = require("../passthrough")
+const {sync} = passthrough
+/** @type {import("./file")} */
+const file = sync.require("./file")
+
+/** Mutates the input. Not recursive - can only include or exclude entire state events. */
+function kstateStripConditionals(kstate) {
+	for (const [k, content] of Object.entries(kstate)) {
+		// conditional for whether a key is even part of the kstate (doing this declaratively on json is hard, so represent it as a property instead.)
+		if ("$if" in content) {
+			if (content.$if) delete content.$if
+			else delete kstate[k]
+		}
+	}
+	return kstate
+}
+
+/** Mutates the input. Works recursively through object tree. */
+async function kstateUploadMxc(obj) {
+	const promises = []
+	function inner(obj) {
+		for (const [k, v] of Object.entries(obj)) {
+			if (v == null || typeof v !== "object") continue
+
+			if (v.$url) {
+				promises.push(
+					file.uploadDiscordFileToMxc(v.$url)
+					.then(mxc => obj[k] = mxc)
+				)
+			}
+
+			inner(v)
+		}
+	}
+	inner(obj)
+	await Promise.all(promises)
+	return obj
+}
+
+/** Automatically strips conditionals and uploads URLs to mxc. */
+async function kstateToState(kstate) {
+	const events = []
+	kstateStripConditionals(kstate)
+	await kstateUploadMxc(kstate)
+	for (const [k, content] of Object.entries(kstate)) {
+		const slashIndex = k.indexOf("/")
+		assert(slashIndex > 0)
+		const type = k.slice(0, slashIndex)
+		const state_key = k.slice(slashIndex + 1)
+		events.push({type, state_key, content})
+	}
+	return events
+}
+
+/**
+ * @param {import("../types").Event.BaseStateEvent[]} events
+ * @returns {any}
+ */
+function stateToKState(events) {
+	const kstate = {}
+	for (const event of events) {
+		kstate[event.type + "/" + event.state_key] = event.content
+	}
+	return kstate
+}
+
+function diffKState(actual, target) {
+	const diff = {}
+	// go through each key that it should have
+	for (const key of Object.keys(target)) {
+		if (!key.includes("/")) throw new Error(`target kstate's key "${key}" does not contain a slash separator; if a blank state_key was intended, add a trailing slash to the kstate key.\ncontext: ${JSON.stringify(target)}`)
+
+		if (key === "m.room.power_levels/") {
+			// Special handling for power levels, we want to deep merge the actual and target into the final state.
+			if (!(key in actual)) throw new Error(`want to apply a power levels diff, but original power level data is missing\nstarted with:  ${JSON.stringify(actual)}\nwant to apply: ${JSON.stringify(target)}`)
+			const temp = mixin({}, actual[key], target[key])
+			if (!isDeepStrictEqual(actual[key], temp)) {
+				// they differ. use the newly prepared object as the diff.
+				diff[key] = temp
+			}
+
+		} else if (key in actual) {
+			// diff
+			if (!isDeepStrictEqual(actual[key], target[key])) {
+				// they differ. use the target as the diff.
+				diff[key] = target[key]
+			}
+
+		} else {
+			// not present, needs to be added
+			diff[key] = target[key]
+		}
+
+		// keys that are missing in "actual" will not be deleted on "target" (no action)
+	}
+	return diff
+}
+
+module.exports.kstateStripConditionals = kstateStripConditionals
+module.exports.kstateUploadMxc = kstateUploadMxc
+module.exports.kstateToState = kstateToState
+module.exports.stateToKState = stateToKState
+module.exports.diffKState = diffKState