CREATE TABLE schoolyears(
  id SERIAL PRIMARY KEY,
  untis_id INTEGER NOT NULL UNIQUE,
  name VARCHAR NOT NULL,
  start_date DATE NOT NULL,
  end_date DATE NOT NULL,
  created_at TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP,
  updated_at TIMESTAMP
);

CREATE TABLE tenants(
  id SERIAL PRIMARY KEY,
  untis_id INTEGER NOT NULL UNIQUE,
  schoolyear_id INTEGER NOT NULL REFERENCES schoolyears(id),
  name VARCHAR NOT NULL,
  active BOOLEAN NOT NULL DEFAULT FALSE,
  created_at TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP,
  updated_at TIMESTAMP
);

CREATE UNIQUE INDEX tenants_active ON tenants(active)
WHERE
  active;

CREATE TABLE teachers(
  id SERIAL PRIMARY KEY,
  untis_id INTEGER NOT NULL UNIQUE,
  schoolyear_id INTEGER NOT NULL REFERENCES schoolyears(id),
  name VARCHAR NOT NULL,
  forename VARCHAR,
  display_name VARCHAR NOT NULL,
  created_at TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP,
  updated_at TIMESTAMP
);

CREATE TABLE classes(
  id SERIAL PRIMARY KEY,
  untis_id INTEGER NOT NULL UNIQUE,
  schoolyear_id INTEGER NOT NULL REFERENCES schoolyears(id),
  name VARCHAR NOT NULL,
  long_name VARCHAR NOT NULL,
  active BOOLEAN NOT NULL,
  created_at TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP,
  updated_at TIMESTAMP
);

CREATE TABLE subjects(
  id SERIAL PRIMARY KEY,
  untis_id INTEGER NOT NULL UNIQUE,
  schoolyear_id INTEGER NOT NULL REFERENCES schoolyears(id),
  name VARCHAR NOT NULL,
  long_name VARCHAR NOT NULL,
  created_at TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP,
  updated_at TIMESTAMP
);

CREATE TABLE rooms(
  id SERIAL PRIMARY KEY,
  untis_id INTEGER NOT NULL UNIQUE,
  schoolyear_id INTEGER NOT NULL REFERENCES schoolyears(id),
  name VARCHAR NOT NULL,
  long_name VARCHAR NOT NULL,
  created_at TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP,
  updated_at TIMESTAMP
);

CREATE TABLE departments(
  id SERIAL PRIMARY KEY,
  untis_id INTEGER NOT NULL UNIQUE,
  schoolyear_id INTEGER NOT NULL REFERENCES schoolyears(id),
  name VARCHAR NOT NULL,
  long_name VARCHAR NOT NULL,
  created_at TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP,
  updated_at TIMESTAMP
);

CREATE TABLE holidays(
  id SERIAL PRIMARY KEY,
  untis_id INTEGER NOT NULL UNIQUE,
  schoolyear_id INTEGER NOT NULL REFERENCES schoolyears(id),
  name VARCHAR NOT NULL,
  long_name VARCHAR NOT NULL,
  start_date DATE NOT NULL,
  end_date DATE NOT NULL,
  created_at TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP,
  updated_at TIMESTAMP
);

CREATE TABLE timegrids(
  id SERIAL PRIMARY KEY,
  schoolyear_id INTEGER NOT NULL REFERENCES schoolyears(id),
  created_at TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP,
  updated_at TIMESTAMP
);

CREATE TABLE timegrid_days(
  id SERIAL PRIMARY KEY,
  timegrid_id INTEGER NOT NULL REFERENCES timegrids(id),
  day_index SMALLINT NOT NULL,
  created_at TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP,
  updated_at TIMESTAMP
);

CREATE TABLE timegrid_time_unit(
  id SERIAL PRIMARY KEY,
  timegrid_day_id INTEGER NOT NULL REFERENCES timegrid_days(id),
  start_time TIME NOT NULL,
  end_time TIME NOT NULL,
  created_at TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP,
  updated_at TIMESTAMP
);

CREATE TABLE substitution_queries(
  id SERIAL PRIMARY KEY,
  schoolyear_id INTEGER NOT NULL REFERENCES schoolyears(id),
  date DATE NOT NULL UNIQUE,
  active BOOLEAN NOT NULL,
  created_at TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP,
  updated_at TIMESTAMP
);

CREATE INDEX substitution_queries_active ON substitution_queries(active);

CREATE TYPE substitution_type AS ENUM (
  'cancel',
  'subst',
  'add',
  'shift',
  'rmchg',
  'rmlk',
  'bs',
  'oh',
  'sb',
  'other',
  'free',
  'exam',
  'ac',
  'holi',
  'stxt'
);

CREATE TABLE substitutions(
  id SERIAL PRIMARY KEY,
  substitution_query_id INTEGER NOT NULL REFERENCES substitution_queries(id),
  subst_type substitution_type NOT NULL,
  lesson_id INTEGER NOT NULL,
  start_time TIME NOT NULL,
  end_time TIME NOT NULL,
  text VARCHAR,
  created_at TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP,
  updated_at TIMESTAMP
);

CREATE TABLE substitution_classes(
  id SERIAL PRIMARY KEY,
  substitution_id INTEGER NOT NULL REFERENCES substitutions(id),
  position SMALLINT NOT NULL,
  class_id INTEGER NOT NULL REFERENCES classes(id),
  created_at TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP,
  updated_at TIMESTAMP
);

CREATE TABLE substitution_teachers(
  id SERIAL PRIMARY KEY,
  substitution_id INTEGER NOT NULL REFERENCES substitutions(id),
  position SMALLINT NOT NULL,
  teacher_id INTEGER REFERENCES teachers(id),
  created_at TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP,
  updated_at TIMESTAMP
);

CREATE TABLE substitution_subjects(
  id SERIAL PRIMARY KEY,
  substitution_id INTEGER NOT NULL REFERENCES substitutions(id),
  position SMALLINT NOT NULL,
  subject_id INTEGER NOT NULL REFERENCES subjects(id),
  created_at TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP,
  updated_at TIMESTAMP
);

CREATE TABLE substitution_rooms(
  id SERIAL PRIMARY KEY,
  substitution_id INTEGER NOT NULL REFERENCES substitutions(id),
  position SMALLINT NOT NULL,
  room_id INTEGER REFERENCES rooms(id),
  created_at TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP,
  updated_at TIMESTAMP
);