import type {CodeKeywordDefinition, AnySchema} from "../../types"
import type KeywordCxt from "../../compile/context"
import {MissingRefError} from "../../compile/error_classes"
import {callValidateCode} from "../code"
import {_, nil, stringify, Code, Name} from "../../compile/codegen"
import N from "../../compile/names"
import {SchemaEnv, resolveRef} from "../../compile"
import {mergeEvaluated} from "../../compile/util"

const def: CodeKeywordDefinition = {
  keyword: "$ref",
  schemaType: "string",
  code(cxt: KeywordCxt) {
    const {gen, schema, it} = cxt
    const {baseId, schemaEnv: env, validateName, opts, self} = it
    // TODO See comment in dynamicRef.ts
    // This has to be improved to resolve #815.
    if (schema === "#" || schema === "#/") return callRootRef()
    const schOrEnv = resolveRef.call(self, env.root, baseId, schema)
    if (schOrEnv === undefined) throw new MissingRefError(baseId, schema)
    if (schOrEnv instanceof SchemaEnv) return callValidate(schOrEnv)
    return inlineRefSchema(schOrEnv)

    function callRootRef(): void {
      if (env === env.root) return callRef(cxt, validateName, env, env.$async)
      const rootName = gen.scopeValue("root", {ref: env.root})
      return callRef(cxt, _`${rootName}.validate`, env.root, env.root.$async)
    }

    function callValidate(sch: SchemaEnv): void {
      const v = getValidate(cxt, sch)
      callRef(cxt, v, sch, sch.$async)
    }

    function inlineRefSchema(sch: AnySchema): void {
      const schName = gen.scopeValue(
        "schema",
        opts.code.source === true ? {ref: sch, code: stringify(sch)} : {ref: sch}
      )
      const valid = gen.name("valid")
      const schCxt = cxt.subschema(
        {
          schema: sch,
          strictSchema: true,
          dataTypes: [],
          schemaPath: nil,
          topSchemaRef: schName,
          errSchemaPath: schema,
        },
        valid
      )
      cxt.mergeEvaluated(schCxt)
      cxt.ok(valid)
    }
  },
}

export function getValidate(cxt: KeywordCxt, sch: SchemaEnv): Code {
  const {gen} = cxt
  return sch.validate
    ? gen.scopeValue("validate", {ref: sch.validate})
    : _`${gen.scopeValue("wrapper", {ref: sch})}.validate`
}

export function callRef(cxt: KeywordCxt, v: Code, sch?: SchemaEnv, $async?: boolean): void {
  const {gen, it} = cxt
  const {allErrors, schemaEnv: env, opts} = it
  const passCxt = opts.passContext ? N.this : nil
  if ($async) callAsyncRef()
  else callSyncRef()

  function callAsyncRef(): void {
    if (!env.$async) throw new Error("async schema referenced by sync schema")
    const valid = gen.let("valid")
    gen.try(
      () => {
        gen.code(_`await ${callValidateCode(cxt, v, passCxt)}`)
        addEvaluatedFrom(v) // TODO will not work with async, it has to be returned with the result
        if (!allErrors) gen.assign(valid, true)
      },
      (e) => {
        gen.if(_`!(${e} instanceof ${it.ValidationError as Name})`, () => gen.throw(e))
        addErrorsFrom(e)
        if (!allErrors) gen.assign(valid, false)
      }
    )
    cxt.ok(valid)
  }

  function callSyncRef(): void {
    cxt.result(
      callValidateCode(cxt, v, passCxt),
      () => addEvaluatedFrom(v),
      () => addErrorsFrom(v)
    )
  }

  function addErrorsFrom(source: Code): void {
    const errs = _`${source}.errors`
    gen.assign(N.vErrors, _`${N.vErrors} === null ? ${errs} : ${N.vErrors}.concat(${errs})`) // TODO tagged
    gen.assign(N.errors, _`${N.vErrors}.length`)
  }

  function addEvaluatedFrom(source: Code): void {
    if (!it.opts.unevaluated) return
    const schEvaluated = sch?.validate?.evaluated
    // TODO refactor
    if (it.props !== true) {
      if (schEvaluated && !schEvaluated.dynamicProps) {
        if (schEvaluated.props !== undefined) {
          it.props = mergeEvaluated.props(gen, schEvaluated.props, it.props)
        }
      } else {
        const props = gen.var("props", _`${source}.evaluated.props`)
        it.props = mergeEvaluated.props(gen, props, it.props, Name)
      }
    }
    if (it.items !== true) {
      if (schEvaluated && !schEvaluated.dynamicItems) {
        if (schEvaluated.items !== undefined) {
          it.items = mergeEvaluated.items(gen, schEvaluated.items, it.items)
        }
      } else {
        const items = gen.var("items", _`${source}.evaluated.items`)
        it.items = mergeEvaluated.items(gen, items, it.items, Name)
      }
    }
  }
}

export default def