import type { ModuleHttpRouteRegistrar, ModuleRouteHandlerContext } from "@ekklesia/module-sdk";
import { SignageError, signageBoundary } from "../errors.js";
import { optionalInstant, optionalString, readJsonObject, requireUuidParam } from "../http.js";
import { SIGNAGE_IMAGE_MAX_BYTES } from "../images/limits.js";
import {
  createImageDeliveryUrls,
  deleteNativeImage,
  ingestNativeImage,
  updateNativeImage,
} from "../images/service.js";
import { readBoundedBody } from "../images/streaming.js";
import { createSignageStore } from "../store/drizzle.js";
import type { StoredImage } from "../store/types.js";

const FILENAME_MAX_LENGTH = 200;

/**
 * A filename is a label an operator sees, never a path and never an object key.
 *
 * Path separators and control characters are refused rather than escaped, because a display name has
 * no business containing either — and the value is echoed back to a browser, where a control
 * character is a rendering hazard and a separator invites something to read it as a location.
 */
function isSafeLabel(value: string): boolean {
  if (value.length === 0 || value.length > FILENAME_MAX_LENGTH) {
    return false;
  }
  for (const character of value) {
    const codePoint = character.codePointAt(0) ?? 0;
    if (codePoint < 0x20 || (codePoint >= 0x7f && codePoint <= 0x9f)) {
      return false;
    }
    if (character === "/" || character === "\\") {
      return false;
    }
  }
  return true;
}

function queryValue(request: Request, name: string): string | undefined {
  const value = new URL(request.url).searchParams.get(name);
  return value === null ? undefined : value;
}

function requireLabel(request: Request, field: string, fallback?: string): string {
  const value = queryValue(request, field)?.trim();
  if (value === undefined || value.length === 0) {
    if (fallback !== undefined) {
      return fallback;
    }
    throw new SignageError("SIGNAGE_INVALID_REQUEST", { field });
  }
  if (!isSafeLabel(value)) {
    throw new SignageError("SIGNAGE_INVALID_REQUEST", { field });
  }
  return value;
}

function readExpiresAt(request: Request): Date | null {
  const raw = queryValue(request, "expiresAt");
  if (raw === undefined || raw === "") {
    // Null is permanent. Local age never invents an expiration for a church's own slide.
    return null;
  }
  const parsed = new Date(raw);
  if (Number.isNaN(parsed.getTime()) || !/[Zz]|[+-]\d{2}:?\d{2}$/u.test(raw)) {
    throw new SignageError("SIGNAGE_INVALID_REQUEST", { field: "expiresAt" });
  }
  return parsed;
}

/** What a browser is given: the record plus fresh, short-lived delivery URLs. The logical object key
 * never leaves the server — a browser has no use for it, and it is the one durable thing Signage
 * stores about where bytes live. */
async function describe(
  context: ModuleRouteHandlerContext,
  image: StoredImage,
): Promise<Record<string, unknown>> {
  const delivery = await createImageDeliveryUrls(context.storage, image.renditions);
  return {
    byteSize: image.originalByteSize,
    contentSha256: image.contentSha256,
    contentType: image.originalContentType,
    createdAt: image.createdAt.toISOString(),
    displayName: image.displayName,
    expiresAt: image.expiresAt?.toISOString() ?? null,
    hasAlpha: image.hasAlpha,
    height: image.height,
    id: image.id,
    originalFilename: image.originalFilename,
    renditions: delivery,
    status: image.status,
    width: image.width,
  };
}

export function registerImageRoutes(http: ModuleHttpRouteRegistrar): void {
  http.route({
    method: "GET",
    path: "/images",
    permission: "signage.view",
    maxBodyBytes: 0,
    handler(_request, context) {
      return signageBoundary(async () => {
        const images = await createSignageStore(context.services.database).listImages();
        return Response.json({
          images: await Promise.all(images.map((image) => describe(context, image))),
        });
      });
    },
  });

  http.route({
    method: "POST",
    path: "/images",
    permission: "signage.assets.manage",
    // One image, streamed. The platform counts bytes as the handler consumes them and never
    // materializes the body; Signage counts them too and refuses at its own smaller limit first.
    // The filename and display name travel in the query string, so the body is exactly the image.
    maxBodyBytes: SIGNAGE_IMAGE_MAX_BYTES,
    bodyMode: "streamed",
    handler(request, context) {
      return signageBoundary(async () => {
        const filename = requireLabel(request, "filename");
        const displayName = requireLabel(request, "displayName", filename);
        const expiresAt = readExpiresAt(request);

        // The whole body is read, and only then validated and committed. A `413` can arrive after a
        // streamed handler has started, which is exactly why nothing is written until this returns.
        const bytes = await readBoundedBody(request, SIGNAGE_IMAGE_MAX_BYTES);

        const result = await ingestNativeImage({
          bytes,
          displayName,
          expiresAt,
          filename,
          storage: context.storage,
          store: createSignageStore(context.services.database),
        });
        return Response.json(
          { deduplicated: result.deduplicated, image: await describe(context, result.image) },
          { status: result.deduplicated ? 200 : 201 },
        );
      });
    },
  });

  http.route({
    method: "GET",
    path: "/images/:imageId",
    permission: "signage.view",
    maxBodyBytes: 0,
    handler(_request, context) {
      return signageBoundary(async () => {
        const imageId = requireUuidParam(context, "imageId");
        const image = await createSignageStore(context.services.database).findImage(imageId);
        if (!image) {
          throw new SignageError("SIGNAGE_NOT_FOUND");
        }
        return Response.json({ image: await describe(context, image) });
      });
    },
  });

  http.route({
    method: "PATCH",
    path: "/images/:imageId",
    permission: "signage.assets.manage",
    // A rename and an expiration date. Nothing about this route needs a large body.
    maxBodyBytes: 4096,
    handler(request, context) {
      return signageBoundary(async () => {
        const imageId = requireUuidParam(context, "imageId");
        const body = await readJsonObject(request);
        const displayName = optionalString(body, "displayName", {
          maxLength: FILENAME_MAX_LENGTH,
        });
        if (displayName !== undefined && !isSafeLabel(displayName)) {
          throw new SignageError("SIGNAGE_INVALID_REQUEST", { field: "displayName" });
        }
        const image = await updateNativeImage({
          assetId: imageId,
          displayName,
          expiresAt: optionalInstant(body, "expiresAt"),
          store: createSignageStore(context.services.database),
        });
        return Response.json({ image: await describe(context, image) });
      });
    },
  });

  http.route({
    method: "DELETE",
    path: "/images/:imageId",
    permission: "signage.assets.manage",
    maxBodyBytes: 0,
    handler(_request, context) {
      return signageBoundary(async () => {
        const imageId = requireUuidParam(context, "imageId");
        await deleteNativeImage({
          assetId: imageId,
          storage: context.storage,
          store: createSignageStore(context.services.database),
        });
        return new Response(null, { status: 204 });
      });
    },
  });
}