From f79da8f7b0486aacab73a5e11663f54a448fad89 Mon Sep 17 00:00:00 2001
From: raveclassic <raveclassic@gmail.com>
Date: Sat, 9 Apr 2022 13:55:32 +0300
Subject: [PATCH] feat(core): trees

---
 packages/core/src/i.ts | 219 ++++++++++++++++++++++++++++++++++-------
 1 file changed, 183 insertions(+), 36 deletions(-)

diff --git a/packages/core/src/i.ts b/packages/core/src/i.ts
index 12e5a1b..c45a876 100644
--- a/packages/core/src/i.ts
+++ b/packages/core/src/i.ts
@@ -1,16 +1,13 @@
-import { Merge, NoInfer, UnionToIntersection } from './utils'
+import { Eq, Merge, NoInfer, UnionToIntersection } from './utils'
 
 interface UnknownDependencyTree {
-  readonly name: PropertyKey
+  readonly name: PropertyKey | never
   readonly type: unknown
   readonly children: readonly UnknownDependencyTree[]
   readonly optional?: true
 }
 
-interface Injectable<
-  Dependencies extends readonly UnknownDependencyTree[],
-  Value
-> {
+interface Injectable<Dependencies extends UnknownDependencyTree, Value> {
   (dependencies: NoInfer<Dependencies>): Value
 }
 
@@ -19,6 +16,17 @@ type InjectableValue<Target> = Target extends Injectable<any, infer Value>
   ? Value
   : never
 
+type InjectableDependencyTree<Target> = Target extends Injectable<
+  infer Tree,
+  any
+>
+  ? Tree
+  : never
+
+type InjectableDependencies<Target> = RunFlattenTree<
+  InjectableDependencyTree<Target>
+>
+
 type MapInjectablesToValues<
   // eslint-disable-next-line @typescript-eslint/no-explicit-any
   Targets extends readonly Injectable<any, unknown>[]
@@ -53,42 +61,83 @@ declare const deps: Deps
 declare function testDeps(input: UnknownDependencyTree): void
 testDeps(deps)
 
-type RunFlattenSingle<DependencyTree> =
-  DependencyTree extends UnknownDependencyTree
-    ? Merge<
-        {
-          readonly [Name in DependencyTree['name'] as DependencyTree['optional'] extends true
-            ? never
-            : Name]: DependencyTree['type']
-        } & {
-          readonly [Name in DependencyTree['name'] as DependencyTree['optional'] extends true
-            ? Name
-            : never]?: DependencyTree['type']
-        } & RunFlattenMany<DependencyTree['children']>
-      >
-    : never
-
-type RunFlatten<DependencyTrees extends readonly UnknownDependencyTree[]> = {
-  readonly [Index in keyof DependencyTrees]: RunFlattenSingle<
-    DependencyTrees[Index]
-  >
+type RunFlattenTree<DependencyTree> = DependencyTree extends never
+  ? {
+      readonly name: never
+      readonly type: never
+      readonly children: readonly []
+    }
+  : DependencyTree extends UnknownDependencyTree
+  ? Merge<
+      {
+        readonly [Name in DependencyTree['name'] as DependencyTree['optional'] extends true
+          ? never
+          : Name]: DependencyTree['type']
+      } & {
+        readonly [Name in DependencyTree['name'] as DependencyTree['optional'] extends true
+          ? Name
+          : never]?: DependencyTree['type']
+      } & UnionToIntersection<
+          RunFlattenChildren<DependencyTree['children']>[number]
+        >
+    >
+  : never
+
+type RunFlattenChildren<Children extends readonly UnknownDependencyTree[]> = {
+  readonly [Index in keyof Children]: RunFlattenTree<Children[Index]>
 }
 
-type RunFlattenMany<Dependencies extends readonly UnknownDependencyTree[]> = {
-  readonly [Key in keyof UnionToIntersection<
-    RunFlatten<Dependencies>[number]
-  >]: UnionToIntersection<RunFlatten<Dependencies>[number]>[Key]
+// type RunFlattenMany<Dependencies extends readonly UnknownDependencyTree[]> = {
+//   readonly [Key in keyof UnionToIntersection<
+//     RunFlatten<Dependencies>[number]
+//   >]: UnionToIntersection<RunFlatten<Dependencies>[number]>[Key]
+// }
+
+type t1 = RunFlattenTree<Deps>
+// type t2 = RunFlattenMany<[Deps]>
+
+export interface TokenAccessor {
+  <Name extends PropertyKey, Dependencies extends Record<Name, unknown>>(
+    dependencies: Dependencies,
+    name: Name
+  ): Dependencies[Name]
 }
+export const TOKEN_ACCESSOR_KEY = '@injectable-ts/core//TOKEN_ACCESSOR'
 
-type t1 = RunFlattenSingle<Deps>
-type t2 = RunFlattenMany<[Deps]>
+declare function token<Name extends PropertyKey>(
+  name: Name
+): <Type = never>() => Injectable<
+  {
+    readonly name: Name
+    readonly type: Type
+    readonly children: readonly [
+      {
+        readonly name: typeof TOKEN_ACCESSOR_KEY
+        readonly type: TokenAccessor
+        readonly optional: true
+        readonly children: readonly []
+      }
+    ]
+  },
+  Type
+>
+
+type MergeDependencies<
+  Inputs extends readonly Injectable<any, any>[],
+  Name extends PropertyKey | never,
+  Type
+> = {
+  readonly name: Name
+  readonly type: Type
+  readonly optional: Name extends never ? undefined : true
+  readonly children: {
+    readonly [Index in keyof Inputs]: InjectableDependencyTree<Inputs[Index]>
+  }
+}
 
 declare function injectable<
   Name extends PropertyKey,
-  Inputs extends readonly Injectable<
-    readonly UnknownDependencyTree[],
-    unknown
-  >[],
+  Inputs extends readonly Injectable<UnknownDependencyTree, unknown>[],
   Value
 >(
   name: Name,
@@ -96,4 +145,102 @@ declare function injectable<
     ...Inputs,
     (...values: MapInjectablesToValues<Inputs>) => Value
   ]
-): Injectable<any, Value>
+): Injectable<
+  {
+    readonly [Key in keyof MergeDependencies<
+      Inputs,
+      Name,
+      Value
+    >]: MergeDependencies<Inputs, Name, Value>[Key]
+  },
+  Value
+>
+declare function injectable<
+  Inputs extends readonly Injectable<UnknownDependencyTree, unknown>[],
+  Value
+>(
+  ...args: readonly [
+    ...Inputs,
+    (...values: MapInjectablesToValues<Inputs>) => Value
+  ]
+): Injectable<MergeDependencies<Inputs, never, Value>, Value>
+
+const d = token('d')<'d'>()
+type D = typeof d
+type DValue = InjectableValue<D>
+type DDependencies = InjectableDependencies<D>
+
+const c = injectable('c', d, (d) => d)
+type C = typeof c
+type CValue = InjectableValue<C>
+type CDependencies = InjectableDependencies<C>
+
+const b = injectable('b', c, (c) => c)
+type B = typeof b
+type BValue = InjectableValue<B>
+type BDependencies = InjectableDependencies<B>
+
+const e = token('e')<'e'>()
+type E = typeof e
+type EValue = InjectableValue<E>
+type EDependencies = InjectableDependencies<E>
+
+const a = injectable('a', b, e, (b, e) => `b: ${b}, e: ${e}` as const)
+type A = typeof a
+type AValue = InjectableValue<A>
+type ADependencies = InjectableDependencies<A>
+
+type ATree = InjectableDependencyTree<A>
+
+type OmitInChildren<Children extends readonly UnknownDependencyTree[], Keys> = {
+  readonly [Index in keyof Children]: RunOmitDependencies<Children[Index], Keys>
+}
+
+type RunOmitDependencies<Tree, Keys> = Tree extends UnknownDependencyTree
+  ? Tree['name'] extends Keys
+    ? never
+    : Omit<Tree, 'children'> & {
+        readonly children: OmitInChildren<Tree['children'], Keys>
+      }
+  : never
+
+declare function provide<Dependencies extends UnknownDependencyTree, Value>(
+  input: Injectable<Dependencies, Value>
+): <Keys extends keyof RunFlattenTree<Dependencies>>() => Injectable<
+  {
+    readonly [Key in keyof RunOmitDependencies<
+      Dependencies,
+      Keys
+    >]: RunOmitDependencies<Dependencies, Keys>[Key]
+  },
+  (innerDependencies: {
+    readonly [Key in keyof RunFlattenTree<Dependencies> as Key extends Keys
+      ? Key
+      : never]: RunFlattenTree<Dependencies>[Key]
+  }) => Value
+>
+
+const withoutD = provide(a)<'d'>()
+type WithoutD = typeof withoutD
+type WithoutDValue = InjectableValue<WithoutD>
+type WithoutDDependencies = InjectableDependencies<WithoutD>
+
+const withoutC = provide(a)<'c'>()
+type WithoutC = typeof withoutC
+type WithoutCValue = InjectableValue<WithoutC>
+type WithoutCDependencies = InjectableDependencies<WithoutC>
+
+const withoutB = provide(a)<'b'>()
+type WithoutB = typeof withoutB
+type WithoutBValue = InjectableValue<WithoutB>
+type WithoutBDependencies = InjectableDependencies<WithoutB>
+
+const withoutE = provide(a)<'e'>()
+type WithoutE = typeof withoutE
+type WithoutEValue = InjectableValue<WithoutE>
+type WithoutEDependencies = InjectableDependencies<WithoutE>
+
+const withoutDE = provide(a)<'d' | 'e'>()
+type WithoutDE = typeof withoutDE
+type WithoutDEValue = InjectableValue<WithoutDE>
+type WithoutDEDependencies = InjectableDependencies<WithoutDE>