-- Migration: Add characters and variables arrays to flowchart_data JSONB default
-- Part of Character/Variable Management feature (US-055)
--
-- The characters and variables arrays are stored within the flowchart_data JSONB column.
-- This migration updates the default value for new projects to include empty arrays.
-- Existing projects without these fields are handled at the application layer,
-- which defaults missing characters/variables to empty arrays on read.

-- =============================================================================
-- UPDATE DEFAULT VALUE FOR flowchart_data
-- =============================================================================
-- Update the default to include characters and variables arrays
ALTER TABLE projects
  ALTER COLUMN flowchart_data
  SET DEFAULT '{"nodes": [], "edges": [], "characters": [], "variables": []}'::jsonb;

-- =============================================================================
-- DOCUMENTATION: JSONB Structure
-- =============================================================================
-- The flowchart_data column now expects the following top-level structure:
--
-- {
--   "nodes": [...],           -- Array of flowchart nodes
--   "edges": [...],           -- Array of flowchart edges
--   "characters": [           -- Array of character definitions
--     {
--       "id": "string",         -- Unique identifier (nanoid)
--       "name": "string",       -- Character name (required, unique per project)
--       "color": "string",      -- Hex color code (e.g., "#FF5733")
--       "description": "string" -- Optional description
--     }
--   ],
--   "variables": [            -- Array of variable definitions
--     {
--       "id": "string",         -- Unique identifier (nanoid)
--       "name": "string",       -- Variable name (required, unique per project)
--       "type": "string",       -- One of: 'numeric', 'string', 'boolean'
--       "initialValue": "any",  -- Initial value matching the type
--       "description": "string" -- Optional description
--     }
--   ]
-- }
--
-- Note: Existing projects that do not have characters/variables fields
-- are handled at the application layer, which defaults them to empty arrays.