import localforage from "localforage";
import { nanoid } from "nanoid";

import { getActiveUserScope } from "@/lib/user-scope";
import { captureVideoPoster, detectVideoAudioTrackFromBlob } from "@/lib/video-poster";
import { resourceFileUrl, resourceIdFromStorageKey, resourceStorageKey, uploadResourceFile } from "@/services/api/resources";
import { uploadImage, type UploadedImage } from "@/services/image-storage";
import { getCachedResourceBlob, getCachedResourceObjectUrl, primeResourceBlobCache } from "@/services/resource-blob-cache";

export type UploadedFile = { url: string; storageKey: string; bytes: number; mimeType: string; width?: number; height?: number; durationMs?: number; hasAudio?: boolean; preview?: UploadedImage };

const store = localforage.createInstance({ name: "infinite-canvas", storeName: "media_files" });
const objectUrls = new Map<string, string>();

export async function uploadMediaFile(input: string | Blob, prefix = "file"): Promise<UploadedFile> {
    const blob = typeof input === "string" ? await (await fetch(input)).blob() : input;
    const previewUrl = URL.createObjectURL(blob);
    const captured = blob.type.startsWith("video/") ? await captureVideoPoster(previewUrl).catch(() => undefined) : undefined;
    // Browser track probes can report a false negative for MP4/MOV files.
    // Re-check only when capture did not positively confirm an audio track so
    // normal uploads avoid an extra full-blob parse.
    const parsedHasAudio = blob.type.startsWith("video/") && captured?.hasAudio !== true ? await detectVideoAudioTrackFromBlob(blob) : undefined;
    const resolvedHasAudio = parsedHasAudio ?? (captured?.hasAudio === false ? undefined : captured?.hasAudio);
    const meta: { width?: number; height?: number; durationMs?: number; hasAudio?: boolean } = captured
        ? { width: captured.width, height: captured.height, durationMs: captured.durationMs, hasAudio: resolvedHasAudio }
        : blob.type.startsWith("audio/")
            ? await readAudioMeta(previewUrl)
            : { hasAudio: resolvedHasAudio };
    const poster = captured?.poster ? await uploadImage(captured.poster).catch(() => undefined) : undefined;
    try {
        const kind = blob.type.startsWith("video/") ? "video" : blob.type.startsWith("audio/") ? "audio" : "file";
        const resource = await uploadResourceFile(blob, kind, { ...meta, fileName: input instanceof File ? input.name : undefined });
        await primeResourceBlobCache(resourceStorageKey(resource.id), blob).catch(() => "");
        URL.revokeObjectURL(previewUrl);
        return { url: resource.publicUrl || resourceFileUrl(resource.id), storageKey: resourceStorageKey(resource.id), bytes: resource.size || blob.size, mimeType: resource.mimeType || blob.type || "application/octet-stream", width: resource.width || meta.width, height: resource.height || meta.height, durationMs: resource.durationMs || meta.durationMs, hasAudio: meta.hasAudio, preview: poster };
    } catch {
        // OSS is optional during local/self-hosted setup. Keep the existing local fallback.
    }
    const storageKey = `${prefix}:${getActiveUserScope()}:${nanoid()}`;
    await store.setItem(storageKey, blob);
    const url = previewUrl;
    objectUrls.set(storageKey, url);
    return { url, storageKey, bytes: blob.size, mimeType: blob.type || "application/octet-stream", ...meta, preview: poster };
}

export async function resolveMediaUrl(storageKey?: string, fallback = "") {
    if (!storageKey) return fallback;
    const resourceId = resourceIdFromStorageKey(storageKey);
    if (resourceId) {
        const cached = await getCachedResourceObjectUrl(storageKey).catch(() => "");
        return cached || resourceFileUrl(resourceId);
    }
    const cached = objectUrls.get(storageKey);
    if (cached) return cached;
    const blob = await store.getItem<Blob>(storageKey);
    if (!blob) return fallback;
    const url = URL.createObjectURL(blob);
    objectUrls.set(storageKey, url);
    return url;
}

export async function getMediaBlob(storageKey: string) {
    if (resourceIdFromStorageKey(storageKey)) return getCachedResourceBlob(storageKey);
    return store.getItem<Blob>(storageKey);
}

export async function setMediaBlob(storageKey: string, blob: Blob) {
    if (resourceIdFromStorageKey(storageKey)) return primeResourceBlobCache(storageKey, blob);
    await store.setItem(storageKey, blob);
    const url = URL.createObjectURL(blob);
    objectUrls.set(storageKey, url);
    return url;
}

export async function deleteStoredMedia(keys: Iterable<string>) {
    await Promise.all(
        Array.from(new Set(keys)).map(async (key) => {
            if (resourceIdFromStorageKey(key)) return;
            const url = objectUrls.get(key);
            if (url) URL.revokeObjectURL(url);
            objectUrls.delete(key);
            await store.removeItem(key);
        }),
    );
}

export async function cleanupUnusedMedia(usedData: unknown, scope = getActiveUserScope()) {
    const usedKeys = collectMediaStorageKeys(usedData);
    const currentScope = scope;
    const unused: string[] = [];
    await store.iterate((_value, key) => {
        const parts = key.split(":");
        if (parts.length >= 3 && parts[1] === currentScope && !usedKeys.has(key)) unused.push(key);
    });
    await Promise.all(unused.map((key) => store.removeItem(key)));
}

export function collectMediaStorageKeys(value: unknown, keys = new Set<string>()) {
    if (!value || typeof value !== "object") return keys;
    if ("storageKey" in value && typeof value.storageKey === "string" && (value.storageKey.includes(":") || resourceIdFromStorageKey(value.storageKey))) keys.add(value.storageKey);
    Object.values(value).forEach((item) => (Array.isArray(item) ? item.forEach((child) => collectMediaStorageKeys(child, keys)) : collectMediaStorageKeys(item, keys)));
    return keys;
}

function readAudioMeta(url: string) {
    return new Promise<{ durationMs?: number }>((resolve) => {
        const audio = document.createElement("audio");
        const done = () => resolve({ durationMs: Number.isFinite(audio.duration) ? Math.round(audio.duration * 1000) : undefined });
        audio.onloadedmetadata = done;
        audio.onerror = done;
        audio.src = url;
    });
}