HDD Corrupted and File system verify or repair failed in Disk Utility

I was reformatting and external HDD on my MBP Mid 2012 non retina, when I decided to abort the process. There was no option to stop or cancel in Disk Utility so I held the power button for 8 secs. It turned off.

Now it can't turn on. I get the white apple screen and the loading bar. It loads till about 80% then the computer shuts down.

I have managed to boot into recovery mode and now from an external HDD running Max OS. I have run First Aid in Disk Utility and I get the following message.

Verifying storage system

Performing fsck_cs -n -x --lv --uuid 67FB0D21-09B1-4DBC-8D41-62CB531A3BE3

Checking volume

disk0s2: Scan for Volume Headers

disk0s2: Scan for Disk Labels

Logical Volume Group 67FB0D21-09B1-4DBC-8D41-62CB531A3BE3 on 1 device

disk0s2: Scan for Metadata Volume

Logical Volume Group has a 24 MB Metadata Volume with double redundancy

Start scanning metadata for a valid checkpoint

Load and verify Segment Headers

Load and verify Checkpoint Payload

Load and verify Transaction Segment

Incorporate 0 newer non-checkpoint transactions

Load and verify Virtual Address Table

Load and verify Segment Usage Table

Load and verify Metadata Superblock

Load and verify Logical Volumes B-Trees

Logical Volume Group contains 1 Logical Volume

Load and verify C39E0E9D-F0AF-4FA5-88DD-DDA2C73E22DF

Load and verify 342A34CC-2F6C-4DF4-BA85-55B1182BD050

Load and verify Freespace Summary

Load and verify Block Accounting

Load and verify Live Virtual Addresses

Newest transaction commit checkpoint is valid

Load and verify Segment Cleaning

The volume 67FB0D21-09B1-4DBC-8D41-62CB531A3BE3 appears to be OK

Storage system check exit code is 0.

Repairing file system.

Volume was successfully unmounted.

Performing fsck_hfs -fy -x /dev/rdisk1

Checking Journaled HFS Plus volume.

Checking extents overflow file.

Checking catalog file.

Missing thread record (id = 28265328)

Incorrect number of thread records

Incorrect number of thread records

Checking multi-linked files.

Checking catalog hierarchy.

Invalid volume file count

(It should be 1493614 instead of 1493616)

Checking extended attributes file.

Checking volume bitmap.

Checking volume information.

Repairing volume.

Missing directory record (id = 28265328)

The volume Macintosh HD could not be repaired.

File system check exit code is 8.

Restoring the original state found as mounted.

Problem -69842 occurred while restoring the original mount state.

File system verify or repair failed.

Operation failed…

Please could someone enlightened me on what I should do next?

I can access my files in the Macintosh HD when booting from the external drive. And I will be backing up my most important data.

But after this,

(a) would a reinstall of OS X on Macintosh HD solve the issue; or

(b) do I need to reformat and reinstall, or

(c) is the internal HDD busted and I have to change it to a new one.

You help will be greatly appreciated.

Thanks!