import { BaseSchema } from '@adonisjs/lucid/schema'

/**
 * Blocks (REBUILD.md, "Voyager 3: window indexing", 1): what a worker leases. A block is a run of consecutive
 * ranges of one group covering at least 30 days of posting time (planned from ranges.est_date and posted_low/high),
 * read in article order through the 24 h window; blocks of a group run in parallel. Ranges stay the unit the
 * prefetcher fetches (the spool, the corpus) and point at their block; the lease, resume point, heartbeat and
 * counts move here. Part of the reset (migration 6000): every range is read again, from the corpus where stored.
 */
export default class extends BaseSchema {
  async up() {
    this.schema.raw(`
      CREATE TABLE blocks (
        id bigserial PRIMARY KEY,
        group_id integer NOT NULL REFERENCES groups (id) ON DELETE CASCADE,
        -- The first range's start and the last range's end.
        start_id bigint NOT NULL,
        end_id bigint NOT NULL,
        -- The resume point: the first article not stored yet (batches are refused out of order, as ranges' were).
        next_id bigint NOT NULL,
        -- The posting time the block covers: estimated when planned, the worker's measured span once done.
        posted_low timestamptz,
        posted_high timestamptz,
        -- planned, leased, done, failed.
        status varchar(8) NOT NULL DEFAULT 'planned',
        -- As ranges': the tail before everything, then the history by era.
        priority integer NOT NULL DEFAULT 0,
        node_id integer,
        attempts integer NOT NULL DEFAULT 0,
        rule_version integer,
        headers bigint NOT NULL DEFAULT 0,
        releases integer NOT NULL DEFAULT 0,
        leased_at timestamptz,
        heartbeat_at timestamptz,
        done_at timestamptz,
        error text,
        created_at timestamptz NOT NULL DEFAULT now(),
        UNIQUE (group_id, start_id)
      )`)
    this.schema.raw(
      `CREATE INDEX blocks_todo_idx ON blocks (priority, id) WHERE status IN ('planned', 'leased')`
    )
    this.schema.raw(`CREATE INDEX blocks_leased_idx ON blocks (leased_at) WHERE status = 'leased'`)
    this.schema.raw(
      `ALTER TABLE ranges ADD COLUMN IF NOT EXISTS block_id bigint REFERENCES blocks (id) ON DELETE SET NULL`
    )
    this.schema.raw(`CREATE INDEX IF NOT EXISTS ranges_block_idx ON ranges (block_id)`)
    // The reset: every range planned again from its start (the corpus serves the stored ones). Priorities, capture,
    // est_date, stored_at, plain_chunks and the measured posted_low/high stay.
    this.schema.raw(`
      UPDATE ranges SET status = 'planned', next_id = start_id, node_id = NULL, attempts = 0, spooled_chunks = 0,
        spooled_at = NULL, leased_at = NULL, heartbeat_at = NULL, done_at = NULL, headers = 0, error = NULL,
        rule_version = NULL
      WHERE status <> 'planned' OR next_id <> start_id OR spooled_chunks <> 0 OR node_id IS NOT NULL`)
  }

  async down() {
    this.schema.raw(`ALTER TABLE ranges DROP COLUMN IF EXISTS block_id`)
    this.schema.raw(`DROP TABLE IF EXISTS blocks`)
  }
}