From d870db59043c75ef5f7a5a259c91a54b3edf7b4c Mon Sep 17 00:00:00 2001
From: Ilia <istudyatuni@gmail.com>
Date: Fri, 27 Oct 2023 23:14:57 +0300
Subject: [PATCH] refactor: use hand-written migrations for stores

---
 src/stores/cache.js          |  4 ++-
 src/stores/migration.js      | 62 +++++++++++-------------------------
 src/stores/migration.test.js | 60 ----------------------------------
 src/stores/settings.js       | 21 ++++++++++--
 4 files changed, 41 insertions(+), 106 deletions(-)
 delete mode 100644 src/stores/migration.test.js

diff --git a/src/stores/cache.js b/src/stores/cache.js
index a3e7445..0066927 100644
--- a/src/stores/cache.js
+++ b/src/stores/cache.js
@@ -8,10 +8,12 @@ const initial = {
 	searches: [],
 }
 
+const migrations = {}
+
 /** Cache store */
 export const cache = localStore('cache', initial)
 
 /** Migrate cache */
 export function migrateCache() {
-	migrateStore(cache, initial)
+	migrateStore(cache, migrations, initial.version)
 }
diff --git a/src/stores/migration.js b/src/stores/migration.js
index e9eee24..4f3b05d 100644
--- a/src/stores/migration.js
+++ b/src/stores/migration.js
@@ -1,50 +1,26 @@
 import { get } from 'svelte/store'
 
-export function migrateStore(store, initial) {
+/**
+ * Migrate `store` using `migrations` to `version`
+ * @param  {import('svelte/store').Writable} store Store to migrate
+ * @param  {{ [key: number]: (data: object, store: import('svelte/store').Writable) => {}}}
+ * migrations Migrations to apply
+ * @param  {number} version    To which version migrate
+ */
+export function migrateStore(store, migrations, version) {
 	let old = get(store)
 	// version could be undefined
-	if ((old.version ?? 0) === initial.version) {
+	if ((old.version ?? 0) === version) {
 		return
 	}
-	let updated = {
-		version: initial.version,
-	}
-	updateFields(initial, old, updated)
-	for (let [k, v] of Object.entries(updated)) {
-		store.set(k, v)
-	}
-}
-
-/** Merge ini and old, put to acc */
-export function updateFields(ini, old, acc) {
-	let keys = new Set([...Object.keys(ini), ...Object.keys(old)])
-	for (let k of keys) {
-		const iniv = ini[k]
-		const oldv = old[k]
-
-		if (typeof iniv === 'undefined') {
-			// new value not defined
-			acc[k] = oldv
-		} else if (typeof oldv === 'undefined') {
-			// old value not defined
-			acc[k] = iniv
-		} else if (typeof iniv === 'object' && iniv !== null) {
-			if (typeof oldv === 'object') {
-				if (oldv !== null) {
-					acc[k] = oldv
-				} else {
-					acc[k] = iniv
-				}
-			} else {
-				// new value is complex object
-				acc[k] = {}
-				updateFields(iniv, oldv, acc[k])
-			}
-		} else if (typeof iniv !== typeof oldv) {
-			// new type of value, we want to replace it
-			acc[k] = iniv
-		} else {
-			acc[k] = oldv
-		}
-	}
+	Object.keys(migrations)
+		.map((v) => parseInt(v))
+		.filter((v) => v > old.version && v <= version)
+		.sort()
+		.forEach((v) => {
+			store.set('version', v)
+			// its possible case that `old` will be changed inside migration,
+			// and this will affect next migrations
+			migrations[v](old, store)
+		})
 }
diff --git a/src/stores/migration.test.js b/src/stores/migration.test.js
deleted file mode 100644
index a64d8f8..0000000
--- a/src/stores/migration.test.js
+++ /dev/null
@@ -1,60 +0,0 @@
-import { it, expect } from 'vitest'
-import { updateFields } from './migration'
-
-it('src/stores/migration:updateFields', () => {
-	let table = [
-		{
-			initial: {},
-			old: {},
-			expected: {},
-			name: 'empty',
-		},
-		{
-			initial: {},
-			old: { a: 5 },
-			expected: { a: 5 },
-			name: 'init empty, old have simple value',
-		},
-		{
-			initial: { a: 5 },
-			old: {},
-			expected: { a: 5 },
-			name: 'old empty, init have simple value',
-		},
-		{
-			initial: {},
-			old: { b: { c: 7 } },
-			expected: { b: { c: 7 } },
-			name: 'init empty, old have object value',
-		},
-		{
-			initial: { a: 5 },
-			old: { a: 8 },
-			expected: { a: 8 },
-			name: 'both have simple value, get from old',
-		},
-		{
-			initial: { a: { c: 8 } },
-			old: { a: 5 },
-			expected: { a: { c: 8 } },
-			name: 'replace simple value with object',
-		},
-		{
-			initial: { a: 5 },
-			old: { a: { c: 8 } },
-			expected: { a: 5 },
-			name: 'replace object with simple value',
-		},
-		{
-			initial: { a: { c: 8 } },
-			old: { a: { c: 5 } },
-			expected: { a: { c: 5 } },
-			name: 'merge',
-		},
-	]
-	for (let { initial, old, expected, name } of table) {
-		let acc = {}
-		updateFields(initial, old, acc)
-		expect(acc, name).toMatchObject(expected)
-	}
-})
diff --git a/src/stores/settings.js b/src/stores/settings.js
index 4158862..03b7c6f 100644
--- a/src/stores/settings.js
+++ b/src/stores/settings.js
@@ -3,6 +3,10 @@ import { localStore } from 'svelte-storages'
 
 import { migrateStore } from 'src/stores/migration'
 
+function getDefaultMapsProvider() {
+	return isMobile({ tablet: true }) ? 'google' : 'osm'
+}
+
 const initial = {
 	version: 3,
 	theme: 'system',
@@ -17,7 +21,20 @@ const initial = {
 	tz: Intl.DateTimeFormat().resolvedOptions().timeZone,
 	/** @type {import('src/utils/types').OsmProvider} */
 	// set to google on mobile to support opening links in mobile app
-	maps_provider: isMobile({ tablet: true }) ? 'google' : 'osm',
+	maps_provider: getDefaultMapsProvider(),
+}
+
+const migrations = {
+	2: (_, s) => {
+		s.maps_provider = getDefaultMapsProvider()
+	},
+	3: (data, s) => {
+		let [name, country] = data.current_city.name.split(', ')
+		let current_city = data.current_city
+		current_city.name = name
+		current_city.country = country || ''
+		s.set('current_city', current_city)
+	},
 }
 
 /** Settings store */
@@ -25,5 +42,5 @@ export const settings = localStore('settings', initial)
 
 /** Migrate settings */
 export function migrateSettings() {
-	migrateStore(settings, initial)
+	migrateStore(settings, migrations, initial.version)
 }