-- Add ISO 8601 compliant timestamp columns to blocks and transactions
-- This migration adds timestamp_iso columns that store ISO 8601 formatted timestamps

-- Add timestamp_iso column to blocks table
ALTER TABLE blocks ADD COLUMN IF NOT EXISTS timestamp_iso VARCHAR(30);

-- Create index for timestamp_iso on blocks
CREATE INDEX IF NOT EXISTS idx_blocks_chain_timestamp_iso ON blocks(chain_id, timestamp_iso);

-- Add timestamp_iso column to transactions table
-- This will be populated from the block timestamp via trigger
ALTER TABLE transactions ADD COLUMN IF NOT EXISTS timestamp_iso VARCHAR(30);

-- Create index for timestamp_iso on transactions
CREATE INDEX IF NOT EXISTS idx_transactions_chain_timestamp_iso ON transactions(chain_id, timestamp_iso);

-- Function to update timestamp_iso from timestamp
CREATE OR REPLACE FUNCTION update_timestamp_iso()
RETURNS TRIGGER AS $$
BEGIN
    NEW.timestamp_iso := to_char(NEW.timestamp, 'YYYY-MM-DD"T"HH24:MI:SS"Z"');
    RETURN NEW;
END;
$$ LANGUAGE plpgsql;

-- Trigger to automatically update timestamp_iso when timestamp changes in blocks
DROP TRIGGER IF EXISTS trigger_blocks_timestamp_iso ON blocks;
CREATE TRIGGER trigger_blocks_timestamp_iso
    BEFORE INSERT OR UPDATE OF timestamp ON blocks
    FOR EACH ROW
    EXECUTE FUNCTION update_timestamp_iso();

-- Function to update transaction timestamp_iso from block timestamp
CREATE OR REPLACE FUNCTION update_transaction_timestamp_iso()
RETURNS TRIGGER AS $$
DECLARE
    block_timestamp TIMESTAMP;
BEGIN
    -- Get the block timestamp
    SELECT b.timestamp INTO block_timestamp
    FROM blocks b
    WHERE b.chain_id = NEW.chain_id AND b.number = NEW.block_number;
    
    -- If block timestamp exists, format it as ISO 8601
    IF block_timestamp IS NOT NULL THEN
        NEW.timestamp_iso := to_char(block_timestamp, 'YYYY-MM-DD"T"HH24:MI:SS"Z"');
    END IF;
    
    RETURN NEW;
END;
$$ LANGUAGE plpgsql;

-- Trigger to automatically update timestamp_iso when transaction is inserted/updated
DROP TRIGGER IF EXISTS trigger_transactions_timestamp_iso ON transactions;
CREATE TRIGGER trigger_transactions_timestamp_iso
    BEFORE INSERT OR UPDATE OF block_number ON transactions
    FOR EACH ROW
    EXECUTE FUNCTION update_transaction_timestamp_iso();

-- Backfill existing blocks with ISO timestamps
UPDATE blocks
SET timestamp_iso = to_char(timestamp, 'YYYY-MM-DD"T"HH24:MI:SS"Z"')
WHERE timestamp_iso IS NULL;

-- Backfill existing transactions with ISO timestamps from blocks
UPDATE transactions t
SET timestamp_iso = to_char(b.timestamp, 'YYYY-MM-DD"T"HH24:MI:SS"Z"')
FROM blocks b
WHERE t.chain_id = b.chain_id 
  AND t.block_number = b.number
  AND t.timestamp_iso IS NULL;