-- Migration 005 — the editable decode map (AGENTS.md §4 FR-17, §7).
--
-- Compass writes a lesson as "[period] - [subject code] - [room code] -
-- [teacher initials]", for example "1 - 7SCF - H14LAB - KNI". The brief must
-- read that as plain English ("Period 1 — Year 7 Science — Room H14LAB — Mr
-- KNI"), so the mapping is data, not code. School codes change between years,
-- so the table is editable and the seed only fills the gaps.
--
-- A code that is not in the table renders as the raw Compass code, never blank.
CREATE TABLE IF NOT EXISTS codes (
    id         INTEGER PRIMARY KEY,
    kind       TEXT    NOT NULL CHECK (kind IN ('subject', 'room', 'teacher', 'period')),
    code       TEXT    NOT NULL,
    name       TEXT    NOT NULL,
    updated_at TEXT    NOT NULL DEFAULT (datetime('now')),
    UNIQUE (kind, code)
);

CREATE INDEX IF NOT EXISTS idx_codes_kind ON codes(kind, code);