How to show the bucket name when using RANGE_BUCKET in bigquery

Here is my query with public dataset in BigQuery:

SELECT RANGE_BUCKET(reputation, [400000, 500000, 600000, 700000, 800000, 900000, 1000000, 1100000, 1200000]) AS reputation_group, COUNT(*) AS count
FROM `bigquery-public-data.stackoverflow.users`
Where reputation > 200000
GROUP BY 1
ORDER By 1

The result is below:

Instead of showing reputation_group as integer, how can I show the bucket's range:

0: [0-400000]
1: [400001-500000]
2: [500001-600000]
....

Thank you very much.

UPDATE: A big thank to Mikhail's answer with a minor change below:

SELECT bucket, 
  FORMAT('%i - %i', IFNULL(ranges[SAFE_OFFSET(bucket - 1)] + 1, 0), ranges[SAFE_OFFSET(bucket)]) AS reputation_group, 
  COUNT(*) AS COUNT
FROM `bigquery-public-data.stackoverflow.users`,
UNNEST([STRUCT([200000, 400000, 500000, 600000, 700000, 800000, 900000, 1000000, 1100000, 1200000] AS ranges)]),
UNNEST([RANGE_BUCKET(reputation, ranges)]) bucket 
WHERE reputation > 200000
GROUP BY 1, 2
ORDER BY bucket

Note an extra item 200000 is added to the STRUCT, which makes the result showing 200001 - 400000 instead of 0 - 400000

Solution

Below is for BigQuery Standard SQL

#standardSQL
SELECT bucket, 
  FORMAT('%i - %i', IFNULL(ranges[SAFE_OFFSET(bucket - 1)] + 1, 0), ranges[SAFE_OFFSET(bucket)]) AS reputation_group, 
  COUNT(*) AS COUNT
FROM `bigquery-public-data.stackoverflow.users`,
UNNEST([STRUCT([400000, 500000, 600000, 700000, 800000, 900000, 1000000, 1100000, 1200000] AS ranges)]),
UNNEST([RANGE_BUCKET(reputation, ranges)]) bucket 
WHERE reputation > 200000
GROUP BY 1, 2
ORDER BY bucket

with result

Row bucket  reputation_group    COUNT    
1   0       0 - 400000          198  
2   1       400001 - 500000     23   
3   2       500001 - 600000     13   
4   3       600001 - 700000     12   
5   4       700001 - 800000     4    
6   5       800001 - 900000     5    
7   6       900001 - 1000000    2    
8   8       1100001 - 1200000   1