-- Migration 037: Rahmen-Slot-„Blueprint“ = eine training_units-Zeile (Ablauf wie echte Einheit)
-- training_framework_slot_exercises migriert nach training_unit_sections / training_unit_section_items,
-- dann entfernt.

-- ── Neue Spalten ───────────────────────────────────────────────────────────────
ALTER TABLE training_units
    ADD COLUMN IF NOT EXISTS framework_slot_id INT REFERENCES training_framework_slots(id)
        ON DELETE CASCADE,
    ADD COLUMN IF NOT EXISTS origin_framework_slot_id INT REFERENCES training_framework_slots(id)
        ON DELETE SET NULL;

-- Genau eine Blueprint-Einheit pro Slot (PostgreSQL UNIQUE erlaubt mehrere NULLs — hier Partial Index)
DROP INDEX IF EXISTS uq_training_units_blueprint_slot;

CREATE UNIQUE INDEX uq_training_units_blueprint_slot
    ON training_units(framework_slot_id)
    WHERE framework_slot_id IS NOT NULL;

CREATE INDEX IF NOT EXISTS idx_training_units_framework_blueprint_calendar
    ON training_units(planned_date, group_id)
    WHERE framework_slot_id IS NULL;

CREATE INDEX IF NOT EXISTS idx_training_units_origin_slot
    ON training_units(origin_framework_slot_id)
    WHERE origin_framework_slot_id IS NOT NULL;

-- ── Nullable für Blueprint-Zeilen ────────────────────────────────────────────
ALTER TABLE training_units ALTER COLUMN planned_date DROP NOT NULL;
ALTER TABLE training_units ALTER COLUMN group_id DROP NOT NULL;

-- ── Für jeden Slot eine Blueprint-Einheit; vorhandene Übungen in erste Sektion ─
DO $$
DECLARE
    rec RECORD;
    new_uid INTEGER;
    new_sec INTEGER;
BEGIN
    FOR rec IN
        SELECT s.id AS sid, fp.created_by AS fp_created_by
        FROM training_framework_slots s
        JOIN training_framework_programs fp ON fp.id = s.framework_program_id
    LOOP
        IF EXISTS (SELECT 1 FROM training_units tu WHERE tu.framework_slot_id = rec.sid) THEN
            CONTINUE;
        END IF;

        INSERT INTO training_units (
            group_id,
            planned_date,
            planned_time_start,
            planned_time_end,
            planned_focus,
            status,
            notes,
            trainer_notes,
            created_by,
            plan_template_id,
            framework_slot_id
        )
        VALUES (
            NULL,
            NULL,
            NULL,
            NULL,
            NULL,
            'planned',
            NULL,
            NULL,
            rec.fp_created_by,
            NULL,
            rec.sid
        )
        RETURNING id INTO new_uid;

        INSERT INTO training_unit_sections (
            training_unit_id,
            order_index,
            title,
            guidance_notes
        )
        VALUES (new_uid, 0, 'Ablauf', NULL)
        RETURNING id INTO new_sec;

        INSERT INTO training_unit_section_items (
            section_id,
            order_index,
            item_type,
            exercise_id,
            exercise_variant_id,
            planned_duration_min,
            actual_duration_min,
            notes,
            modifications,
            note_body
        )
        SELECT
            new_sec,
            sf.order_index,
            'exercise'::character varying(20),
            sf.exercise_id,
            sf.exercise_variant_id,
            NULL::integer,
            NULL::integer,
            NULL::text,
            NULL::text,
            NULL::text
        FROM training_framework_slot_exercises sf
        WHERE sf.slot_id = rec.sid
        ORDER BY sf.order_index;
    END LOOP;
END $$;

DROP TABLE IF EXISTS training_framework_slot_exercises;

ALTER TABLE training_units DROP CONSTRAINT IF EXISTS chk_training_units_blueprint_vs_scheduled;

ALTER TABLE training_units
    ADD CONSTRAINT chk_training_units_blueprint_vs_scheduled CHECK (
        (
            framework_slot_id IS NOT NULL
            AND group_id IS NULL
            AND planned_date IS NULL
            AND origin_framework_slot_id IS NULL
        )
        OR (
            framework_slot_id IS NULL
            AND group_id IS NOT NULL
            AND planned_date IS NOT NULL
        )
    );