Compile feeds to filters as far as possible

packages/custom-feeds/index.ts

@@ -1,6 +1,6 @@
 import {inc, now, isNil} from '@coracle.social/lib'
 import type {Rumor, Filter} from '@coracle.social/util'
-import {Tags, getIdFilters} from '@coracle.social/util'
+import {Tags, getIdFilters, mergeFilters} from '@coracle.social/util'
 
 // TODO:
 // - if one of the feeds in a union is a filter, don't execute it,
@@ -83,28 +83,57 @@ export type ExecuteOpts = {
 export class Interpreter {
   constructor(readonly opts: InterpreterOpts) {}
 
+  // Dispatch to different types of feed
+
   execute([type, ...feed]: Feed, opts: ExecuteOpts) {
-    switch (type) {
+    switch(type) {
       case FeedType.Difference:
-        return this.executeDifference(feed as Feed[], opts)
+        return this._executeDifference(feed as Feed[], opts)
       case FeedType.Intersection:
-        return this.executeIntersection(feed as Feed[], opts)
+        return this._executeIntersection(feed as Feed[], opts)
       case FeedType.SymmetricDifference:
-        return this.executeSymmetricDifference(feed as Feed[], opts)
-      case FeedType.Union:
-        return this.executeUnion(feed as Feed[], opts)
-      case FeedType.Filter:
-        return this.executeFilter(feed as DynamicFilter[], opts)
-      case FeedType.List:
-        return this.executeList(feed as string[], opts)
-      case FeedType.LOL:
-        return this.executeLOL(feed as string[], opts)
-      case FeedType.DVM:
-        return this.executeDVM(feed as DVMRequest[], opts)
+        return this._executeSymmetricDifference(feed as Feed[], opts)
+      default:
+        return this._feedToFilters([type, ...feed] as Feed).then(filters =>
+          this.opts.reqFilters(filters.map(this._compileFilter), opts)
+        )
     }
   }
 
-  executeDifference(feeds: Feed[], {onEvent, onComplete}: ExecuteOpts) {
+  async _feedToFilters([type, ...feed]: Feed) {
+    switch(type) {
+      case FeedType.Union:
+        return await this._unionToFilters(feed as Feed[])
+      case FeedType.List:
+        return await this._listsToFilters(feed as string[])
+      case FeedType.LOL:
+        return await this._lolsToFilters(feed as string[])
+      case FeedType.DVM:
+        return await this._dvmsToFilters(feed as DVMRequest[])
+      case FeedType.Filter:
+        return feed as Filter[]
+      default:
+        throw new Error(`Unable to convert feed of type ${type} to filters`)
+    }
+  }
+
+  async _feedsToFilters(feeds: Feed[]) {
+    const filters: Filter[] = []
+
+    await Promise.all(
+      feeds.map(async feed => {
+        for (const filter of await this._feedToFilters(feed)) {
+          filters.push(this._compileFilter(filter))
+        }
+      })
+    )
+
+    return filters
+  }
+
+  // Special-case executors for set operations we can't infer filters for
+
+  async _executeDifference(feeds: Feed[], {onEvent, onComplete}: ExecuteOpts) {
     const skip = new Set<string>()
     const events: Rumor[] = []
 
@@ -130,7 +159,7 @@ export class Interpreter {
     })
   }
 
-  executeIntersection(feeds: Feed[], {onEvent, onComplete}: ExecuteOpts) {
+  async _executeIntersection(feeds: Feed[], {onEvent, onComplete}: ExecuteOpts) {
     const counts = new Map<string, number>()
     const events = new Map<string, Rumor>()
 
@@ -153,7 +182,7 @@ export class Interpreter {
     })
   }
 
-  executeSymmetricDifference(feeds: Feed[], {onEvent, onComplete}: ExecuteOpts) {
+  async _executeSymmetricDifference(feeds: Feed[], {onEvent, onComplete}: ExecuteOpts) {
     const counts = new Map<string, number>()
     const events = new Map<string, Rumor>()
 
@@ -176,70 +205,54 @@ export class Interpreter {
     })
   }
 
-  executeUnion(feeds: Feed[], {onEvent, onComplete}: ExecuteOpts) {
-    const getOnComplete = this.#getCompletionTracker(onComplete)
+  // Everything else can be compiled to filters
 
-    for (const subFeed of feeds) {
-      this.execute(subFeed, {onEvent, onComplete: getOnComplete})
-    }
+  async _unionToFilters(feeds: Feed[]): Promise<Filter[]> {
+    return mergeFilters(await this._feedsToFilters(feeds))
   }
 
-  executeFilter(filters: DynamicFilter[], opts: ExecuteOpts) {
-    this.opts.reqFilters(filters.map(this.#compileFilter), opts)
-  }
+  async _listsToFilters(addresses: string[]): Promise<Filter[]> {
+    return new Promise(resolve => {
+      const events: Rumor[] = []
 
-  executeList(addresses: string[], {onEvent, onComplete}: ExecuteOpts) {
-    const getOnComplete = this.#getCompletionTracker(onComplete)
-
-    this.opts.reqFilters(getIdFilters(addresses), {
-      onComplete: getOnComplete(),
-      onEvent: (event: Rumor) => {
-        this.opts.reqFilters(this.#getFiltersFromTags(Tags.fromEvent(event)), {
-          onEvent,
-          onComplete: getOnComplete(),
-        })
-      },
-    })
-  }
-
-  executeLOL(addresses: string[], {onEvent, onComplete}: ExecuteOpts) {
-    const getOnComplete = this.#getCompletionTracker(onComplete)
-
-    this.opts.reqFilters(getIdFilters(addresses), {
-      onComplete: getOnComplete(),
-      onEvent: (event: Rumor) => {
-        const addresses = Tags.fromEvent(event).values("a").valueOf()
-
-        this.opts.reqFilters(getIdFilters(addresses), {
-          onComplete: getOnComplete(),
-          onEvent: (event: Rumor) => {
-            this.opts.reqFilters(this.#getFiltersFromTags(Tags.fromEvent(event)), {
-              onEvent,
-              onComplete: getOnComplete(),
-            })
-          },
-        })
-      },
-    })
-  }
-
-  executeDVM(requests: DVMRequest[], {onEvent, onComplete}: ExecuteOpts) {
-    const getOnComplete = this.#getCompletionTracker(onComplete)
-
-    for (const request of requests) {
-      this.opts.reqDvm(request, {
-        onComplete: getOnComplete(),
-        onEvent: (event: Rumor) => {
-          this.opts.reqFilters(this.#getFiltersFromTags(Tags.fromEvent(event)), {
-            onEvent,
-            onComplete: getOnComplete(),
-          })
-        },
+      this.opts.reqFilters(getIdFilters(addresses), {
+        onEvent: (event: Rumor) => events.push(event),
+        onComplete: () => resolve(this._getFiltersFromTags(Tags.fromEvents(events))),
       })
-    }
+    })
   }
 
-  #getCompletionTracker(onComplete?: () => void) {
+  async _lolsToFilters(addresses: string[]): Promise<Filter[]> {
+    return new Promise(resolve => {
+      const events: Rumor[] = []
+
+      this.opts.reqFilters(getIdFilters(addresses), {
+        onEvent: (event: Rumor) => events.push(event),
+        onComplete: () => resolve(this._listsToFilters(Tags.fromEvents(events).values("a").valueOf())),
+      })
+    })
+  }
+
+  async _dvmsToFilters(requests: DVMRequest[]): Promise<Filter[]> {
+    const events: Rumor[] = []
+
+    await Promise.all(
+      requests.map(request => {
+        return new Promise<void>(resolve => {
+          this.opts.reqDvm(request, {
+            onEvent: (event: Rumor) => events.push(event),
+            onComplete: resolve,
+          })
+        })
+      })
+    )
+
+    return this._getFiltersFromTags(Tags.fromEvents(events))
+  }
+
+  // Utilities
+
+  _getCompletionTracker(onComplete?: () => void) {
     let pending = 0
 
     return () => {
@@ -255,7 +268,7 @@ export class Interpreter {
     }
   }
 
-  #compileFilter({scopes, min_wot, max_wot, until_ago, since_ago, ...filter}: DynamicFilter) {
+  _compileFilter({scopes, min_wot, max_wot, until_ago, since_ago, ...filter}: DynamicFilter) {
     if (scopes && !filter.authors) {
       filter.authors = scopes.flatMap(scope => this.opts.getPubkeysForScope(scope))
     }
@@ -272,10 +285,10 @@ export class Interpreter {
       filter.since = now() - since_ago!
     }
 
-    return filter
+    return filter as Filter
   }
 
-  #getFiltersFromTags(tags: Tags) {
+  _getFiltersFromTags(tags: Tags) {
     const ttags = tags.values("t")
     const ptags = tags.values("p")
     const eatags = tags.filterByKey(["e", "a"]).values()