-- Migration 012: Unique constraint on (profile_id, date, focus)
-- v9d Phase 2a: Prevent duplicate rest day types per date
-- Date: 2026-03-22

-- Add focus column (extracted from rest_config for performance + constraints)
ALTER TABLE rest_days
ADD COLUMN IF NOT EXISTS focus VARCHAR(20);

-- Populate from existing JSONB data
UPDATE rest_days
SET focus = rest_config->>'focus'
WHERE focus IS NULL;

-- Make NOT NULL (safe because we just populated all rows)
ALTER TABLE rest_days
ALTER COLUMN focus SET NOT NULL;

-- Add CHECK constraint for valid focus values
ALTER TABLE rest_days
ADD CONSTRAINT valid_focus CHECK (
    focus IN ('muscle_recovery', 'cardio_recovery', 'mental_rest', 'deload', 'injury')
);

-- Add UNIQUE constraint: Same profile + date + focus = duplicate
ALTER TABLE rest_days
ADD CONSTRAINT unique_rest_day_per_focus
UNIQUE (profile_id, date, focus);

-- Add index for efficient queries by focus
CREATE INDEX IF NOT EXISTS idx_rest_days_focus
ON rest_days(focus);

-- Comment for documentation
COMMENT ON COLUMN rest_days.focus IS 'Extracted from rest_config.focus for performance and constraints. Prevents duplicate rest day types per date.';