import fs from "node:fs/promises";
import path from "node:path";
import { dbGlobal } from "drizzle-pkg/lib/db";
import { users } from "drizzle-pkg/lib/schema/auth";
import { userConfigs } from "drizzle-pkg/lib/schema/config";
import { mediaAssets, mediaRefs, postComments, posts, timelineEvents } from "drizzle-pkg/lib/schema/content";
import { and, eq, inArray, lte, or } from "drizzle-orm";
import { MEDIA_REF_OWNER_POST } from "../../constants/media-refs";
import type { ExportMaskPolicy } from "../../constants/export";
import { sanitizeUserForExport } from "../../utils/export-mask";

export type BuildExportDataResult = {
  dataFiles: Array<{ file: string; rowCount: number }>;
  totalRows: number;
};

async function writeDataFile(baseDir: string, fileName: string, payload: unknown): Promise<{ file: string; rowCount: number }> {
  const file = `data/${fileName}`;
  const fullPath = path.resolve(baseDir, fileName);
  await fs.writeFile(fullPath, `${JSON.stringify(payload, null, 2)}\n`, "utf8");
  const rowCount = Array.isArray(payload) ? payload.length : payload ? 1 : 0;
  return { file, rowCount };
}

export async function buildExportDataJson(params: {
  userId: number;
  maskPolicy: ExportMaskPolicy;
  cutoffAt: Date;
  outputDataDir: string;
}): Promise<BuildExportDataResult> {
  await fs.mkdir(params.outputDataDir, { recursive: true });

  const [userRow] = await dbGlobal.select().from(users).where(eq(users.id, params.userId)).limit(1);
  if (!userRow) {
    throw new Error(`user not found: ${params.userId}`);
  }

  const sanitizedUser = sanitizeUserForExport(userRow as unknown as Record<string, unknown>, params.maskPolicy);

  const [postRows, timelineRows, mediaRows, configRows] = await Promise.all([
    dbGlobal
      .select()
      .from(posts)
      .where(and(eq(posts.userId, params.userId), lte(posts.createdAt, params.cutoffAt))),
    dbGlobal
      .select()
      .from(timelineEvents)
      .where(and(eq(timelineEvents.userId, params.userId), lte(timelineEvents.createdAt, params.cutoffAt))),
    dbGlobal
      .select()
      .from(mediaAssets)
      .where(and(eq(mediaAssets.userId, params.userId), lte(mediaAssets.createdAt, params.cutoffAt))),
    dbGlobal
      .select()
      .from(userConfigs)
      .where(and(eq(userConfigs.userId, params.userId), lte(userConfigs.updatedAt, params.cutoffAt))),
  ]);

  const postIds = postRows.map((p) => p.id);
  const commentCondition =
    postIds.length === 0
      ? and(lte(postComments.createdAt, params.cutoffAt), eq(postComments.authorUserId, params.userId))
      : and(
          lte(postComments.createdAt, params.cutoffAt),
          or(eq(postComments.authorUserId, params.userId), inArray(postComments.postId, postIds)),
        );
  const commentRowsRaw = await dbGlobal.select().from(postComments).where(commentCondition);

  const mediaRefRows =
    postIds.length === 0
      ? []
      : await dbGlobal
          .select()
          .from(mediaRefs)
          .where(and(eq(mediaRefs.ownerType, MEDIA_REF_OWNER_POST), inArray(mediaRefs.ownerId, postIds)));
  const commentRows = commentRowsRaw.map((row) =>
    params.maskPolicy === "masked"
      ? sanitizeUserForExport(row as unknown as Record<string, unknown>, params.maskPolicy)
      : row,
  );
  const configRowsMasked = configRows.map((row) =>
    params.maskPolicy === "masked"
      ? sanitizeUserForExport(row as unknown as Record<string, unknown>, params.maskPolicy)
      : row,
  );

  const dataFiles = await Promise.all([
    writeDataFile(params.outputDataDir, "user.json", sanitizedUser),
    writeDataFile(params.outputDataDir, "posts.json", postRows),
    writeDataFile(params.outputDataDir, "timeline.json", timelineRows),
    writeDataFile(params.outputDataDir, "comments.json", commentRows),
    writeDataFile(params.outputDataDir, "media-assets.json", mediaRows),
    writeDataFile(params.outputDataDir, "media-refs.json", mediaRefRows),
    writeDataFile(params.outputDataDir, "user-configs.json", configRowsMasked),
  ]);

  const totalRows = dataFiles.reduce((sum, item) => sum + item.rowCount, 0);

  return { dataFiles, totalRows };
}

export async function listExportUserMediaAssets(params: {
  userId: number;
  cutoffAt: Date;
}): Promise<Array<{ storageKey: string }>> {
  const rows = await dbGlobal
    .select({
      storageKey: mediaAssets.storageKey,
    })
    .from(mediaAssets)
    .where(and(eq(mediaAssets.userId, params.userId), lte(mediaAssets.createdAt, params.cutoffAt)));
  return rows;
}