// Timeline block commands — command pattern for undo/redo support
// All mutations go through these commands, which also sync to the backend.
// Backend sync is fire-and-forget (no await during rapid undo/redo).

let currentShowId = null;

export function setCurrentShowId(id) {
    currentShowId = id;
}

function syncBlock(showId, deviceId, block, method) {
    if (!showId) return;  // no show loaded yet — skip sync
    const base = `/api/shows/${showId}/tracks/${deviceId}/blocks`;
    const opts = { method, headers: { 'Content-Type': 'application/json' } };
    if (method === 'POST' || method === 'PATCH') {
        opts.body = JSON.stringify(block);
    }
    const url = method === 'POST' ? base : `${base}/${block.id}`;
    fetch(url, opts).catch(e => console.warn('[sync]', e));
}

// ── PlaceBlockCommand ────────────────────────────────────────────────────────

export class PlaceBlockCommand {
    constructor(tracks, block) {
        this.tracks = tracks;
        this.block = block;  // {id, timestamp, duration, animation, params, device_id}
    }

    execute() {
        const track = this.tracks.find(t => t.device_id === this.block.device_id);
        if (track) track.cues.push(this.block);
        syncBlock(currentShowId, this.block.device_id, this.block, 'POST');
    }

    undo() {
        const track = this.tracks.find(t => t.device_id === this.block.device_id);
        if (track) track.cues = track.cues.filter(c => c.id !== this.block.id);
        syncBlock(currentShowId, this.block.device_id, this.block, 'DELETE');
    }
}

// ── MoveBlockCommand ─────────────────────────────────────────────────────────

export class MoveBlockCommand {
    constructor(tracks, block, oldTimestamp, newTimestamp) {
        this.tracks = tracks;
        this.block = block;
        this.oldTimestamp = oldTimestamp;
        this.newTimestamp = newTimestamp;
    }

    execute() {
        this.block.timestamp = this.newTimestamp;
        syncBlock(currentShowId, this.block.device_id, this.block, 'PATCH');
    }

    undo() {
        this.block.timestamp = this.oldTimestamp;
        syncBlock(currentShowId, this.block.device_id, this.block, 'PATCH');
    }
}

// ── ResizeBlockCommand ───────────────────────────────────────────────────────
// Left-edge resize changes both timestamp and duration (right edge stays fixed).
// Right-edge resize changes only duration.

export class ResizeBlockCommand {
    constructor(tracks, block, oldTimestamp, oldDuration, newTimestamp, newDuration) {
        this.tracks = tracks;
        this.block = block;
        this.oldTimestamp = oldTimestamp;
        this.oldDuration = oldDuration;
        this.newTimestamp = newTimestamp;
        this.newDuration = newDuration;
    }

    execute() {
        this.block.timestamp = this.newTimestamp;
        this.block.duration = this.newDuration;
        syncBlock(currentShowId, this.block.device_id, this.block, 'PATCH');
    }

    undo() {
        this.block.timestamp = this.oldTimestamp;
        this.block.duration = this.oldDuration;
        syncBlock(currentShowId, this.block.device_id, this.block, 'PATCH');
    }
}

// ── DeleteBlockCommand ───────────────────────────────────────────────────────

export class DeleteBlockCommand {
    constructor(tracks, block) {
        this.tracks = tracks;
        this.block = block;
    }

    execute() {
        const track = this.tracks.find(t => t.device_id === this.block.device_id);
        if (track) track.cues = track.cues.filter(c => c.id !== this.block.id);
        syncBlock(currentShowId, this.block.device_id, this.block, 'DELETE');
    }

    undo() {
        const track = this.tracks.find(t => t.device_id === this.block.device_id);
        if (track) track.cues.push(this.block);
        syncBlock(currentShowId, this.block.device_id, this.block, 'POST');
    }
}