import { useMemo } from "react";
import type { MidiMessage } from "../../midi-contract/midi-message.types.js";
import { adaptOutput } from "../../port/web-midi-port.js";
import { useMidiContextOrThrow } from "../use-midi-context.js";
import type { PortSelector } from "../use-midi-input/use-midi-input.js";

export interface MidiOutputHandle {
    readonly id: string;
    readonly name: string;
    readonly manufacturer: string | undefined;
    readonly state: "connected" | "disconnected";
    send(bytes: Uint8Array): void;
    sendMessage(msg: MidiMessage): void;
}

/**
 * Returns a typed output handle for the selected Web MIDI output, or
 * `null` while access is loading / the selector misses. The handle's
 * `sendMessage` encodes a `MidiMessage` via `encodeMessage` and
 * forwards the resulting bytes to the underlying `MIDIOutput.send`;
 * `send(bytes)` is the raw escape-hatch (typically used for SysEx
 * pass-through).
 */
export function useMidiOutput(selector: PortSelector): MidiOutputHandle | null {
    const ctx = useMidiContextOrThrow();
    const stateVersion = ctx.stateVersion;
    return useMemo<MidiOutputHandle | null>(() => {
        void stateVersion;
        if (ctx.access === null) {
            return null;
        }
        if (selector === "first") {
            const next = ctx.access.outputs.values().next();
            return next.done === true ? null : adaptOutput(next.value);
        }
        const target = ctx.access.outputs.get(selector);
        return target === undefined ? null : adaptOutput(target);
    }, [ctx.access, stateVersion, selector]);
}