-- migrate:up

-- Tags are shared by the time slots and the tasks
ALTER TABLE slot_tags RENAME TO tags;
ALTER TABLE tags RENAME CONSTRAINT slot_tags_pkey TO tags_pkey;
ALTER SEQUENCE slot_tags_id_seq RENAME TO tags_id_seq;

INSERT INTO tags ("name", color) VALUES
    ('{"fr": "Devoir", "en": "Homework"}', '#9333ea'),
    ('{"fr": "Examen", "en": "Exam"}', '#dc2626'),
    ('{"fr": "Projet", "en": "Project"}', '#0891b2');

-- Grades of a course, on any scale: `score` out of `max_score`. The weights are relative
-- to each other, the average of the course is weighted by them.
CREATE TABLE grades (
    id SERIAL PRIMARY KEY,
    course_id INTEGER NOT NULL REFERENCES courses (id) ON DELETE CASCADE,
    "name" TEXT NOT NULL,
    score DOUBLE PRECISION NOT NULL CHECK (score >= 0),
    max_score DOUBLE PRECISION NOT NULL CHECK (max_score > 0),
    weight DOUBLE PRECISION NOT NULL CHECK (weight > 0),
    CHECK (score <= max_score)
);

CREATE INDEX grades_course_id_idx ON grades (course_id);

-- Homework, exams, or anything to do for a course. A task may have subtasks (one level).
CREATE TABLE tasks (
    id SERIAL PRIMARY KEY,
    course_id INTEGER NOT NULL REFERENCES courses (id) ON DELETE CASCADE,
    parent_id INTEGER REFERENCES tasks (id) ON DELETE CASCADE,
    "name" TEXT NOT NULL,
    description TEXT,
    links TEXT[] NOT NULL DEFAULT '{}',
    deadline TIMESTAMPTZ,
    done BOOLEAN NOT NULL DEFAULT FALSE
);

CREATE INDEX tasks_course_id_idx ON tasks (course_id);

CREATE TABLE task_tags (
    task_id INTEGER NOT NULL REFERENCES tasks (id) ON DELETE CASCADE,
    tag_id INTEGER NOT NULL REFERENCES tags (id) ON DELETE CASCADE,
    PRIMARY KEY (task_id, tag_id)
);

-- Lecture notes written in markdown. The content (.md) and the rendered pdf are files
-- in the storage, not in the database.
CREATE TABLE lecture_notes (
    id SERIAL PRIMARY KEY,
    course_id INTEGER NOT NULL REFERENCES courses (id) ON DELETE CASCADE,
    title TEXT NOT NULL,
    -- False when the last rendering to pdf failed
    has_pdf BOOLEAN NOT NULL DEFAULT FALSE,
    created_at TIMESTAMPTZ NOT NULL DEFAULT now(),
    updated_at TIMESTAMPTZ NOT NULL DEFAULT now()
);

CREATE INDEX lecture_notes_course_id_idx ON lecture_notes (course_id);

-- migrate:down
DROP TABLE IF EXISTS lecture_notes;
DROP TABLE IF EXISTS task_tags;
DROP TABLE IF EXISTS tasks;
DROP TABLE IF EXISTS grades;

DELETE FROM tags WHERE id NOT IN (SELECT DISTINCT tag_id FROM time_slots) AND id > 3;
ALTER SEQUENCE tags_id_seq RENAME TO slot_tags_id_seq;
ALTER TABLE tags RENAME CONSTRAINT tags_pkey TO slot_tags_pkey;
ALTER TABLE tags RENAME TO slot_tags;