import { describe, test, expect, beforeAll, afterAll } from 'bun:test';
import { sha256 } from '@noble/hashes/sha2.js';
import { NotFoundError, type FileEntry } from '../../src/index.js';
import type { UserReadResult, UserWriteArgs, WriteResult } from '../../src/server/io-types.js';
import type { OpContext } from '../../src/server/handler-context.js';
import { setupFileRig, type FileTestRig } from './helpers/rig.js';

interface StoredBlob {
  bytes: Uint8Array;
  contentType?: string;
  sha256: string;
  mtime: number;
}

function bytesToHex(b: Uint8Array): string {
  return Array.from(b, (x) => x.toString(16).padStart(2, '0')).join('');
}

describe('Content I/O — inline read/write E2E', () => {
  let rig: FileTestRig;
  const blobs = new Map<string, StoredBlob>();

  beforeAll(async () => {
    blobs.clear();
    rig = await setupFileRig({
      read: async (ctx: OpContext<{ path: string }>): Promise<UserReadResult> => {
        const blob = blobs.get(ctx.path);
        if (blob === undefined) throw new NotFoundError(ctx.path);
        return blob.contentType !== undefined
          ? { kind: 'inline', bytes: blob.bytes, sha256: blob.sha256, contentType: blob.contentType }
          : { kind: 'inline', bytes: blob.bytes, sha256: blob.sha256 };
      },
      write: async (ctx: OpContext<UserWriteArgs>): Promise<WriteResult> => {
        const args = ctx.args;
        if (args.content.kind !== 'inline') {
          throw new Error('expected inline content for this test');
        }
        if (blobs.has(args.path) && !args.overwrite) {
          throw new Error('exists');
        }
        const stored: StoredBlob = {
          bytes: args.content.bytes,
          ...(args.contentType !== undefined ? { contentType: args.contentType } : {}),
          sha256: args.content.sha256,
          mtime: Date.now(),
        };
        blobs.set(args.path, stored);
        const entry: FileEntry = {
          name: args.path.split('/').filter(Boolean).pop() ?? '',
          kind: 'file',
          size: args.content.size,
          mtime: stored.mtime,
          ...(args.contentType !== undefined ? { contentType: args.contentType } : {}),
          metadata: { sha256: args.content.sha256 },
        };
        return { entry };
      },
    });
  });

  afterAll(async () => {
    await rig.teardown();
  });

  test('write 1 KiB inline → read it back, sha256 matches', async () => {
    const data = new Uint8Array(1024);
    for (let i = 0; i < data.length; i++) data[i] = (i * 7) & 0xff;
    const expectedSha = bytesToHex(sha256(data));

    const writeResult = await rig.fs.write('/small.bin', data, { contentType: 'application/octet-stream' });
    expect(writeResult.entry.size).toBe(1024);
    expect(writeResult.entry.metadata.sha256).toBe(expectedSha);

    const readResult = await rig.fs.read('/small.bin');
    expect(readResult.kind).toBe('inline');
    if (readResult.kind === 'inline') {
      expect(readResult.bytes.byteLength).toBe(1024);
      expect(readResult.sha256).toBe(expectedSha);
      expect(readResult.contentType).toBe('application/octet-stream');
      expect(Array.from(readResult.bytes)).toEqual(Array.from(data));
    }
  });

  test('write 100 KiB inline → read it back, sha256 matches', async () => {
    const data = new Uint8Array(100 * 1024);
    crypto.getRandomValues(data);
    const expectedSha = bytesToHex(sha256(data));

    await rig.fs.write('/big.bin', data);
    const readResult = await rig.fs.read('/big.bin');
    expect(readResult.kind).toBe('inline');
    if (readResult.kind === 'inline') {
      expect(readResult.bytes.byteLength).toBe(100 * 1024);
      expect(readResult.sha256).toBe(expectedSha);
      expect(Array.from(readResult.bytes)).toEqual(Array.from(data));
    }
  });

  test('overwrite without flag → server-defined error; with flag → succeeds', async () => {
    const a = new Uint8Array([1, 2, 3]);
    const b = new Uint8Array([4, 5, 6]);
    await rig.fs.write('/dup.bin', a);
    await expect(rig.fs.write('/dup.bin', b)).rejects.toThrow();
    await rig.fs.write('/dup.bin', b, { overwrite: true });
    const out = await rig.fs.read('/dup.bin');
    expect(out.kind).toBe('inline');
    if (out.kind === 'inline') {
      expect(Array.from(out.bytes)).toEqual([4, 5, 6]);
    }
  });

  test('write Blob input → inferred contentType, round-trips', async () => {
    const blob = new Blob([new Uint8Array([0xde, 0xad, 0xbe, 0xef])], { type: 'image/png' });
    await rig.fs.write('/blobby.png', blob);
    const out = await rig.fs.read('/blobby.png');
    expect(out.kind).toBe('inline');
    if (out.kind === 'inline') {
      expect(out.contentType).toBe('image/png');
      expect(Array.from(out.bytes)).toEqual([0xde, 0xad, 0xbe, 0xef]);
    }
  });

  test('read non-existent → NotFoundError', async () => {
    await expect(rig.fs.read('/missing.bin')).rejects.toThrow();
  });

  test('inline path also handles 256 KiB exactly (boundary)', async () => {
    const data = new Uint8Array(256 * 1024);
    crypto.getRandomValues(data);
    const expectedSha = bytesToHex(sha256(data));
    await rig.fs.write('/boundary.bin', data);
    const out = await rig.fs.read('/boundary.bin');
    expect(out.kind).toBe('inline');
    if (out.kind === 'inline') {
      expect(out.sha256).toBe(expectedSha);
    }
  });
});
