-- Rollback: Restore old course hierarchy
-- Note: This will lose any new data created with the simplified structure

-- Step 1: Recreate old tables
CREATE TABLE IF NOT EXISTS programs (
    id BIGSERIAL PRIMARY KEY,
    course_id BIGINT NOT NULL REFERENCES courses(id) ON DELETE CASCADE,
    title VARCHAR(255) NOT NULL,
    description TEXT,
    thumbnail TEXT,
    display_order INT NOT NULL DEFAULT 0,
    is_active BOOLEAN NOT NULL DEFAULT TRUE
);

CREATE TABLE IF NOT EXISTS levels (
    id BIGSERIAL PRIMARY KEY,
    program_id BIGINT NOT NULL REFERENCES programs(id) ON DELETE CASCADE,
    title VARCHAR(255) NOT NULL,
    description TEXT,
    level_index INT NOT NULL,
    number_of_modules INT NOT NULL DEFAULT 0,
    number_of_practices INT NOT NULL DEFAULT 0,
    number_of_videos INT NOT NULL DEFAULT 0,
    is_active BOOLEAN NOT NULL DEFAULT TRUE
);

CREATE TABLE IF NOT EXISTS modules (
    id BIGSERIAL PRIMARY KEY,
    level_id BIGINT NOT NULL REFERENCES levels(id) ON DELETE CASCADE,
    title VARCHAR(255) NOT NULL,
    content TEXT,
    display_order INT NOT NULL DEFAULT 0,
    is_active BOOLEAN NOT NULL DEFAULT TRUE
);

CREATE TABLE IF NOT EXISTS module_videos (
    id BIGSERIAL PRIMARY KEY,
    module_id BIGINT NOT NULL REFERENCES modules(id) ON DELETE CASCADE,
    title VARCHAR(255) NOT NULL,
    description TEXT,
    video_url TEXT NOT NULL,
    duration INT NOT NULL,
    resolution VARCHAR(20),
    is_published BOOLEAN NOT NULL DEFAULT FALSE,
    publish_date TIMESTAMPTZ,
    visibility VARCHAR(50),
    instructor_id VARCHAR(100),
    thumbnail TEXT,
    is_active BOOLEAN NOT NULL DEFAULT TRUE
);

-- Step 2: Restore practices polymorphic columns
ALTER TABLE practices ADD COLUMN IF NOT EXISTS owner_type VARCHAR(50);
ALTER TABLE practices ADD COLUMN IF NOT EXISTS owner_id BIGINT;

-- Step 3: Recreate old indexes
CREATE INDEX IF NOT EXISTS idx_programs_course_id ON programs(course_id);
CREATE INDEX IF NOT EXISTS idx_levels_program_id ON levels(program_id);
CREATE INDEX IF NOT EXISTS idx_modules_level_id ON modules(level_id);
CREATE INDEX IF NOT EXISTS idx_videos_module_id ON module_videos(module_id);
CREATE INDEX IF NOT EXISTS idx_practices_owner ON practices(owner_type, owner_id);

-- Step 4: Drop new tables
ALTER TABLE practices DROP CONSTRAINT IF EXISTS practices_sub_course_id_fkey;
DROP INDEX IF EXISTS idx_practices_sub_course_id;
ALTER TABLE practices DROP COLUMN IF EXISTS sub_course_id;

DROP TABLE IF EXISTS sub_course_videos CASCADE;
DROP TABLE IF EXISTS sub_courses CASCADE;

-- Step 5: Add back constraint on practices
ALTER TABLE practices ADD CONSTRAINT practices_owner_type_check CHECK (owner_type IN ('LEVEL', 'MODULE'));