-- Seed provenance and inventory (#50): where "German Red Garlic" came from, and
-- how much of it is left.
--
-- Two modelling calls worth stating, because both look like omissions otherwise:
--
--   1. The plant catalog stays FLAT. No species→variety hierarchy. A row in your
--      catalog just is the thing you plant — "German Red Garlic" is a plant row,
--      and the built-in "Garlic" is a generic starting point you clone. A
--      hierarchy buys taxonomy nobody asked for and complicates every join.
--
--   2. Inventory belongs to a PURCHASE, not to a variety. You might buy the same
--      garlic from two vendors in two years at two prices and two germination
--      rates. Quantity columns on plants would collapse all of that into one
--      number and lose it, so lots get their own table.
--
-- Nothing here is destructive: plants gains two defaulted columns, the built-ins
-- keep working with empty strings, and plantings gains a nullable link.
ALTER TABLE plants ADD COLUMN source_url TEXT NOT NULL DEFAULT '';
ALTER TABLE plants ADD COLUMN vendor     TEXT NOT NULL DEFAULT '';

-- owner_id sits on the LOT rather than being inherited from the plant, because a
-- lot may reference a built-in plant (you can buy generic Garlic from Johnny's)
-- while still being nobody's business but yours. Lots are never shared along
-- with a garden.
CREATE TABLE seed_lots (
    id              INTEGER PRIMARY KEY,
    owner_id        INTEGER NOT NULL REFERENCES users (id)  ON DELETE CASCADE,
    plant_id        INTEGER NOT NULL REFERENCES plants (id) ON DELETE CASCADE,
    vendor          TEXT    NOT NULL DEFAULT '',
    source_url      TEXT    NOT NULL DEFAULT '',
    sku             TEXT    NOT NULL DEFAULT '',
    lot_code        TEXT    NOT NULL DEFAULT '',
    purchased_at    TEXT,                                   -- 'YYYY-MM-DD'
    packed_for_year INTEGER,
    quantity        REAL    NOT NULL DEFAULT 0,
    unit            TEXT    NOT NULL CHECK (unit IN ('seeds','grams','ounces','packets','bulbs','plants')),
    cost_cents      INTEGER,
    germination_pct REAL,
    notes           TEXT    NOT NULL DEFAULT '',
    version         INTEGER NOT NULL DEFAULT 1,
    created_at      TEXT    NOT NULL DEFAULT (strftime('%Y-%m-%dT%H:%M:%SZ', 'now')),
    updated_at      TEXT    NOT NULL DEFAULT (strftime('%Y-%m-%dT%H:%M:%SZ', 'now'))
);

CREATE INDEX idx_seed_lots_owner ON seed_lots (owner_id);
CREATE INDEX idx_seed_lots_plant ON seed_lots (plant_id);

-- Which lot a planting came out of. ON DELETE SET NULL rather than CASCADE:
-- retiring a lot must never destroy planting history — the plants really were in
-- the ground, whatever happened to the record of the packet.
ALTER TABLE plantings ADD COLUMN seed_lot_id INTEGER REFERENCES seed_lots (id) ON DELETE SET NULL;

CREATE INDEX idx_plantings_seed_lot ON plantings (seed_lot_id) WHERE seed_lot_id IS NOT NULL;