import ts from 'typescript';

import { DecoratorMeta, NodeTransformer, State, TransformPhase, TransformerType, Transformer, ModuleNameSymbol } from './types/visitor.ts';

const HandlersSymbol = Symbol();

type TransformerWithHandlers = Transformer & { [HandlersSymbol]?: NodeTransformer[] };

function isTransformer(x: unknown): x is Transformer {
  return x !== null && x !== undefined && typeof x === 'function';
}

/**
 * Get all transformers
 * @param obj Object to search for transformers
 */
export function getAllTransformers(obj: Record<string, { [HandlersSymbol]?: NodeTransformer[] }>, module: string): NodeTransformer[] {
  return Object.values(obj)
    .flatMap(x => {
      if (isTransformer(x)) {
        x[ModuleNameSymbol] = module;
      }
      return (x[HandlersSymbol] ?? []);
    })
    .map(handler => ({
      ...handler,
      key: `${module}:${handler.key}`,
      target: handler.target?.map(t => `${module}:${t}`)
    }));
}

// Store handlers in class
function storeHandler(cls: TransformerWithHandlers, fn: Function, phase: TransformPhase, type: TransformerType, target?: string[]): void {
  (cls[HandlersSymbol] ??= []).push({ key: fn.name, [phase]: fn.bind(cls), type, target });
}

/**
 * Wraps entire file before transforming
 */
export function OnFile(...target: string[]) {
  return <S extends State = State, R extends ts.Node = ts.Node>(
    inst: Transformer, __: unknown, d: TypedPropertyDescriptor<(state: S, node: ts.SourceFile) => R>
  ): void => storeHandler(inst, d.value!, 'before', 'file', target);
}

/**
 * Wraps entire file after transforming
 */
export function AfterFile(...target: string[]) {
  return <S extends State = State, R extends ts.Node = ts.Node>(
    inst: Transformer, __: unknown, d: TypedPropertyDescriptor<(state: S, node: ts.SourceFile) => R>
  ): void => storeHandler(inst, d.value!, 'before', 'file', target);
}

/**
 * Listens for a `ts.CallExpression`, on descent
 */
export function OnCall(...target: string[]) {
  return <S extends State = State, R extends ts.Node = ts.Node>(
    inst: Transformer, __: unknown, d: TypedPropertyDescriptor<(state: S, node: ts.CallExpression) => R>
  ): void => storeHandler(inst, d.value!, 'before', 'call', target);
}

/**
 * Listens for a `ts.FunctionDeclaration`, on descent
 */
export function OnFunction(...target: string[]) {
  return <S extends State = State, R extends ts.Node = ts.Node>(
    inst: Transformer, __: unknown, d: TypedPropertyDescriptor<(state: S, node: ts.FunctionDeclaration | ts.FunctionExpression) => R>
  ): void => storeHandler(inst, d.value!, 'before', 'function', target);
}

/**
 * Listens for a `ts.ParameterDeclaration`, on descent
 */
export function OnParameter(...target: string[]) {
  return <S extends State = State, R extends ts.Node = ts.Node>(
    inst: Transformer, __: unknown, d: TypedPropertyDescriptor<(state: S, node: ts.ParameterDeclaration, dm?: DecoratorMeta) => R>
  ): void => storeHandler(inst, d.value!, 'before', 'parameter', target);
}

/**
 * Listens for a `ts.PropertyDeclaration`, on descent
 */
export function OnProperty(...target: string[]) {
  return <S extends State = State, R extends ts.Node = ts.Node>(
    inst: Transformer, __: unknown, d: TypedPropertyDescriptor<(state: S, node: ts.PropertyDeclaration, dm?: DecoratorMeta) => R>
  ): void => storeHandler(inst, d.value!, 'before', 'property', target);
}

/**
 * Listens for a `ts.GetAccessorDeclaration`, on descent
 */
export function OnGetter(...target: string[]) {
  return <S extends State = State, R extends ts.Node = ts.Node>(
    inst: Transformer, __: unknown, d: TypedPropertyDescriptor<(state: S, node: ts.GetAccessorDeclaration, dm?: DecoratorMeta) => R>
  ): void => storeHandler(inst, d.value!, 'before', 'getter', target);
}

/**
 * Listens for a `ts.SetAccessorDeclaration`, on descent
 */
export function OnSetter(...target: string[]) {
  return <S extends State = State, R extends ts.Node = ts.Node>(
    inst: Transformer, __: unknown, d: TypedPropertyDescriptor<(state: S, node: ts.SetAccessorDeclaration, dm?: DecoratorMeta) => R>
  ): void => storeHandler(inst, d.value!, 'before', 'setter', target);
}

/**
 * Listens for a `ts.MethodDeclaration`, on descent
 */
export function OnMethod(...target: string[]) {
  return <S extends State = State, R extends ts.Node = ts.Node>(
    inst: Transformer, __: unknown, d: TypedPropertyDescriptor<(state: S, node: ts.MethodDeclaration, dm?: DecoratorMeta) => R>
  ): void => storeHandler(inst, d.value!, 'before', 'method', target);
}

/**
 * Listens for a static `ts.MethodDeclaration`, on descent
 */
export function OnStaticMethod(...target: string[]) {
  return <S extends State = State, R extends ts.Node = ts.Node>(
    inst: Transformer, __: unknown, d: TypedPropertyDescriptor<(state: S, node: ts.MethodDeclaration, dm?: DecoratorMeta) => R>
  ): void => storeHandler(inst, d.value!, 'before', 'static-method', target);
}

/**
 * Listens for a `ts.ClassDeclaration`, on descent
 */
export function OnClass(...target: string[]) {
  return <S extends State = State, R extends ts.Node = ts.Node>(
    inst: Transformer, __: unknown, d: TypedPropertyDescriptor<(state: S, node: ts.ClassDeclaration, dm?: DecoratorMeta) => R>
  ): void => storeHandler(inst, d.value!, 'before', 'class', target);
}

/**
 * Listens for a `ts.TypeAliasDeclaration` on descent
 */
export function OnTypeAlias(...target: string[]) {
  return <S extends State = State, R extends ts.Node = ts.Node>(
    inst: Transformer, __: unknown, d: TypedPropertyDescriptor<(state: S, node: ts.TypeAliasDeclaration) => R>
  ): void => storeHandler(inst, d.value!, 'before', 'type', target);
}

/**
 * Listens for a `ts.InterfaceDeclaration` on descent
 */
export function OnInterface(...target: string[]) {
  return <S extends State = State, R extends ts.Node = ts.Node>(
    inst: Transformer, __: unknown, d: TypedPropertyDescriptor<(state: S, node: ts.InterfaceDeclaration) => R>
  ): void => storeHandler(inst, d.value!, 'before', 'interface', target);
}

/**
 * Listens for a `ts.CallExpression`, on ascent
 */
export function AfterCall(...target: string[]) {
  return <S extends State = State, R extends ts.Node = ts.Node>(
    inst: Transformer, __: unknown, d: TypedPropertyDescriptor<(state: S, node: ts.CallExpression, dm?: DecoratorMeta) => R>
  ): void => storeHandler(inst, d.value!, 'after', 'call', target);
}

/**
 * Listens for a `ts.FunctionDeclaration`, on descent
 */
export function AfterFunction(...target: string[]) {
  return <S extends State = State, R extends ts.Node = ts.Node>(
    inst: Transformer, __: unknown, d: TypedPropertyDescriptor<(state: S, node: ts.FunctionDeclaration | ts.FunctionExpression) => R>
  ): void => storeHandler(inst, d.value!, 'after', 'function', target);
}

/**
 * Listens for a `ts.ParameterDeclaration`, on ascent
 */
export function AfterParameter(...target: string[]) {
  return <S extends State = State, R extends ts.Node = ts.Node>(
    inst: Transformer, __: unknown, d: TypedPropertyDescriptor<(state: S, node: ts.ParameterDeclaration, dm?: DecoratorMeta) => R>
  ): void => storeHandler(inst, d.value!, 'after', 'parameter', target);
}

/**
 * Listens for a `ts.PropertyDeclaration`, on ascent
 */
export function AfterProperty(...target: string[]) {
  return <S extends State = State, R extends ts.Node = ts.Node>(
    inst: Transformer, __: unknown, d: TypedPropertyDescriptor<(state: S, node: ts.PropertyDeclaration, dm?: DecoratorMeta) => R>
  ): void => storeHandler(inst, d.value!, 'after', 'property', target);
}

/**
 * Listens for a `ts.GetAccessorDeclaration`, on ascent
 */
export function AfterGetter(...target: string[]) {
  return <S extends State = State, R extends ts.Node = ts.Node>(
    inst: Transformer, __: unknown, d: TypedPropertyDescriptor<(state: S, node: ts.GetAccessorDeclaration, dm?: DecoratorMeta) => R>
  ): void => storeHandler(inst, d.value!, 'after', 'getter', target);
}

/**
 * Listens for a `ts.SetAccessorDeclaration`, on ascent
 */
export function AfterSetter(...target: string[]) {
  return <S extends State = State, R extends ts.Node = ts.Node>(
    inst: Transformer, __: unknown, d: TypedPropertyDescriptor<(state: S, node: ts.SetAccessorDeclaration, dm?: DecoratorMeta) => R>
  ): void => storeHandler(inst, d.value!, 'after', 'setter', target);
}

/**
 * Listens for a `ts.MethodDeclaration`, on ascent
 */
export function AfterMethod(...target: string[]) {
  return <S extends State = State, R extends ts.Node = ts.Node>(
    inst: Transformer, __: unknown, d: TypedPropertyDescriptor<(state: S, node: ts.MethodDeclaration, dm?: DecoratorMeta) => R>
  ): void => storeHandler(inst, d.value!, 'after', 'method', target);
}

/**
 * Listens for a static `ts.MethodDeclaration`, on ascent
 */
export function AfterStaticMethod(...target: string[]) {
  return <S extends State = State, R extends ts.Node = ts.Node>(
    inst: Transformer, __: unknown, d: TypedPropertyDescriptor<(state: S, node: ts.MethodDeclaration, dm?: DecoratorMeta) => R>
  ): void => storeHandler(inst, d.value!, 'after', 'static-method', target);
}

/**
 * Listens for a `ts.ClassDeclaration`, on ascent
 */
export function AfterClass(...target: string[]) {
  return <S extends State = State, R extends ts.Node = ts.Node>(
    inst: Transformer, __: unknown, d: TypedPropertyDescriptor<(state: S, node: ts.ClassDeclaration, dm?: DecoratorMeta) => R>
  ): void => storeHandler(inst, d.value!, 'after', 'class', target);
}


/**
 * Listens for a `ts.TypeAliasDeclaration` on ascent
 */
export function AfterTypeAlias(...target: string[]) {
  return <S extends State = State, R extends ts.Node = ts.Node>(
    inst: Transformer, __: unknown, d: TypedPropertyDescriptor<(state: S, node: ts.TypeAliasDeclaration) => R>
  ): void => storeHandler(inst, d.value!, 'after', 'type', target);
}

/**
 * Listens for a `ts.InterfaceDeclaration` on ascent
 */
export function AfterInterface(...target: string[]) {
  return <S extends State = State, R extends ts.Node = ts.Node>(
    inst: Transformer, __: unknown, d: TypedPropertyDescriptor<(state: S, node: ts.InterfaceDeclaration) => R>
  ): void => storeHandler(inst, d.value!, 'after', 'interface', target);
}