import { Array, Cause, Chunk, type Context, Effect, Exit, Fiber, identity, Option, ParseResult, Pipeable, Predicate, Schema, type Scope, Stream } from "effect"
import * as Form from "./Form.js"
import * as Lens from "./Lens.js"
import * as Mutation from "./Mutation.js"
import * as Result from "./Result.js"
import * as Subscribable from "./Subscribable.js"
import * as SubscriptionRef from "./SubscriptionRef.js"


export const SubmittableFormTypeId: unique symbol = Symbol.for("@effect-fc/Form/SubmittableForm")
export type SubmittableFormTypeId = typeof SubmittableFormTypeId

export interface SubmittableForm<in out A, in out I = A, in out R = never, in out MA = void, in out ME = never, in out MR = never, in out MP = never>
extends Form.Form<readonly [], A, I, never, never> {
    readonly [SubmittableFormTypeId]: SubmittableFormTypeId

    readonly schema: Schema.Schema<A, I, R>
    readonly context: Context.Context<Scope.Scope | R>
    readonly mutation: Mutation.Mutation<
        readonly [value: A, form: SubmittableForm<A, I, R, unknown, unknown, unknown>],
        MA, ME, MR, MP
    >
    readonly validationFiber: Subscribable.Subscribable<Option.Option<Fiber.Fiber<A, ParseResult.ParseError>>, never, never>

    readonly run: Effect.Effect<void>
    readonly submit: Effect.Effect<Option.Option<Result.Final<MA, ME, MP>>, Cause.NoSuchElementException>
}

export class SubmittableFormImpl<in out A, in out I = A, in out R = never, in out MA = void, in out ME = never, in out MR = never, in out MP = never>
extends Pipeable.Class() implements SubmittableForm<A, I, R, MA, ME, MR, MP> {
    readonly [Form.FormTypeId]: Form.FormTypeId = Form.FormTypeId
    readonly [SubmittableFormTypeId]: SubmittableFormTypeId = SubmittableFormTypeId

    readonly path = [] as const

    constructor(
        readonly schema: Schema.Schema<A, I, R>,
        readonly context: Context.Context<Scope.Scope | R>,
        readonly mutation: Mutation.Mutation<
            readonly [value: A, form: SubmittableForm<A, I, R, unknown, unknown, unknown>],
            MA, ME, MR, MP
        >,
        readonly value: Lens.Lens<Option.Option<A>, never, never, never, never>,
        readonly encodedValue: Lens.Lens<I, never, never, never, never>,
        readonly issues: Lens.Lens<readonly ParseResult.ArrayFormatterIssue[], never, never, never, never>,
        readonly validationFiber: Lens.Lens<Option.Option<Fiber.Fiber<A, ParseResult.ParseError>>, never, never, never, never>,
        readonly isValidating: Subscribable.Subscribable<boolean, never, never>,

        readonly canCommit: Subscribable.Subscribable<boolean, never, never>,
        readonly isCommitting: Subscribable.Subscribable<boolean, never, never>,

        readonly runSemaphore: Effect.Semaphore,
    ) {
        super()
    }

    get run(): Effect.Effect<void> {
        return this.runSemaphore.withPermits(1)(Stream.runForEach(
            this.encodedValue.changes,

            encodedValue => Lens.get(this.validationFiber).pipe(
                Effect.andThen(Option.match({
                    onSome: Fiber.interrupt,
                    onNone: () => Effect.void,
                })),
                Effect.andThen(
                    Effect.forkScoped(Effect.onExit(
                        Schema.decode(this.schema, { errors: "all" })(encodedValue),
                        exit => Effect.andThen(
                            Exit.matchEffect(exit, {
                                onSuccess: v => Effect.andThen(
                                    Lens.set(this.value, Option.some(v)),
                                    Lens.set(this.issues, Array.empty()),
                                ),
                                onFailure: c => Option.match(Chunk.findFirst(Cause.failures(c), e => e._tag === "ParseError"), {
                                    onSome: e => Effect.flatMap(
                                        ParseResult.ArrayFormatter.formatError(e),
                                        v => Lens.set(this.issues, v),
                                    ),
                                    onNone: () => Effect.void,
                                }),
                            }),
                            Lens.set(this.validationFiber, Option.none()),
                        ),
                    )).pipe(
                        Effect.tap(fiber => Lens.set(this.validationFiber, Option.some(fiber))),
                        Effect.andThen(Fiber.join),
                        Effect.forkScoped,
                    )
                ),
                Effect.provide(this.context),
            ),
        ))
    }

    get submit(): Effect.Effect<Option.Option<Result.Final<MA, ME, MP>>, Cause.NoSuchElementException> {
        return Lens.get(this.value).pipe(
            Effect.andThen(identity),
            Effect.andThen(value => this.submitValue(value)),
        )
    }

    submitValue(value: A): Effect.Effect<Option.Option<Result.Final<MA, ME, MP>>> {
        return Effect.whenEffect(
            Effect.tap(
                this.mutation.mutate([value, this as any]),
                result => Result.isFailure(result)
                    ? Option.match(
                        Chunk.findFirst(
                            Cause.failures(result.cause as Cause.Cause<ParseResult.ParseError>),
                            e => e._tag === "ParseError",
                        ),
                        {
                            onSome: e => Effect.flatMap(
                                ParseResult.ArrayFormatter.formatError(e),
                                v => Lens.set(this.issues, v),
                            ),
                            onNone: () => Effect.void,
                        },
                    )
                    : Effect.void
            ),
            this.canCommit.get,
        )
    }
}


export const isSubmittableForm = (u: unknown): u is SubmittableForm<unknown, unknown, unknown, unknown, unknown, unknown, unknown> => Predicate.hasProperty(u, SubmittableFormTypeId)

export declare namespace makeSubmittable {
    export interface Options<in out A, in out I = A, in out R = never, in out MA = void, in out ME = never, in out MR = never, in out MP = never>
    extends Mutation.make.Options<
        readonly [value: NoInfer<A>, form: SubmittableForm<NoInfer<A>, NoInfer<I>, NoInfer<R>, unknown, unknown, unknown>],
        MA, ME, MR, MP
    > {
        readonly schema: Schema.Schema<A, I, R>
        readonly initialEncodedValue: NoInfer<I>
    }
}

export const makeSubmittable = Effect.fnUntraced(function* <A, I = A, R = never, MA = void, ME = never, MR = never, MP = never>(
    options: makeSubmittable.Options<A, I, R, MA, ME, MR, MP>
): Effect.fn.Return<
    SubmittableForm<A, I, R, MA, ME, Result.forkEffect.OutputContext<MR, MP>, MP>,
    never,
    Scope.Scope | R | Result.forkEffect.OutputContext<MR, MP>
> {
    const mutation = yield* Mutation.make(options)
    const valueLens = Lens.fromSubscriptionRef(yield* SubscriptionRef.make(Option.none<A>()))
    const issuesLens = Lens.fromSubscriptionRef(yield* SubscriptionRef.make<readonly ParseResult.ArrayFormatterIssue[]>(Array.empty()))
    const validationFiberLens = Lens.fromSubscriptionRef(yield* SubscriptionRef.make(Option.none<Fiber.Fiber<A, ParseResult.ParseError>>()))

    return new SubmittableFormImpl(
        options.schema,
        yield* Effect.context<Scope.Scope | R>(),
        mutation,

        valueLens,
        Lens.fromSubscriptionRef(yield* SubscriptionRef.make(options.initialEncodedValue)),
        issuesLens,
        validationFiberLens,
        Subscribable.map(validationFiberLens, Option.isSome),

        Subscribable.map(
            Subscribable.zipLatestAll(valueLens, issuesLens, validationFiberLens, mutation.result),
            ([value, issues, validationFiber, result]) => (
                Option.isSome(value) &&
                Array.isEmptyReadonlyArray(issues) &&
                Option.isNone(validationFiber) &&
                !(Result.isRunning(result) || Result.hasRefreshingFlag(result))
            ),
        ),
        Subscribable.map(mutation.result, result => Result.isRunning(result) || Result.hasRefreshingFlag(result)),

        yield* Effect.makeSemaphore(1),
    )
})

export declare namespace serviceSubmittable {
    export interface Options<in out A, in out I = A, in out R = never, in out MA = void, in out ME = never, in out MR = never, in out MP = never>
    extends makeSubmittable.Options<A, I, R, MA, ME, MR, MP> {}
}

export const serviceSubmittable = <A, I = A, R = never, MA = void, ME = never, MR = never, MP = never>(
    options: serviceSubmittable.Options<A, I, R, MA, ME, MR, MP>
): Effect.Effect<
    SubmittableForm<A, I, R, MA, ME, Result.forkEffect.OutputContext<MR, MP>, MP>,
    never,
    Scope.Scope | R | Result.forkEffect.OutputContext<MR, MP>
> => Effect.tap(
    makeSubmittable(options),
    form => Effect.forkScoped(form.run),
)