Bryce
3ecd115f76
Capture the proven whole-form hx-select swap method as a reusable skill so every later modal migration is cheaper and consistent. No app code changes. - SKILL.md: the per-migration playbook (classify → baseline → characterize → consolidate render fns → templatize → wire HTMX → collapse routes → verify → commit → feed skill) + Growth contract + non-negotiables. - reference/swap-doctrine.md: the four swap rules, focus invariant, Alpine-survives- swap hardening, target-selector strategy — worked from the real edit.clj swaps (memo no-request, account→location targeted cell, amount→totals sibling-tbody, vendor/mode/row whole-form). 0 OOB. - reference/render-functions.md: explicit-data or top-rooted cursor; the MapCursor fake + transaction-account-row-no-cursor* twin as the smell to remove. - reference/form-vs-wizard.md: classification + the data-driven session-backed (formtools SessionStorage) engine that replaces the snapshot round-trip + protocol. - reference/selmer-conventions.md: STUB, validated in Phase 2. - component-cookbook.md / gotchas.md / test-recipes.md / scorecard.md: seeded from what transaction-edit proves (7 cookbook entries, caret-survival + typeahead test recipes, scorecard baseline LOC 1608 / ~12 routes / 1 no-cursor twin / 2 faked roots / 0 OOB). Scorecard (Transaction Edit baseline, before Phase 2): LOC 1608, routes ~12, no-cursor twins 1, faked-cursor roots 2, snapshot merges ~75, OOB 0, mixed hx- 8.
116 lines
5.4 KiB
Markdown
116 lines
5.4 KiB
Markdown
# Forms vs. wizards (and the data-driven wizard engine)
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## Classify first
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| Signal | Classification |
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|--------|----------------|
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| One logical step — even with a `?mode=` toggle, $/% radio, or add/remove rows | **plain form** |
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| The user genuinely advances through ordered steps, each validated before the next | **wizard** |
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| In doubt | **form** |
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Most "wizards" in this codebase are single-step forms wearing wizard costumes: they
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implement the multi-step protocol (`mm/ModalWizardStep` + friends), serialize an EDN
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snapshot into hidden fields, and register 10–20 stacked-middleware routes — all for one
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step. That is pure overhead to delete.
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## The machinery being replaced
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`transaction/edit.clj` today still carries the old shape, useful as the "before":
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```clojure
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(defrecord LinksStep [linear-wizard]
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mm/ModalWizardStep
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(step-name [_] "Transaction Actions")
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(step-key [_] :links)
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(edit-path [_ _] [])
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(step-schema [_] (mm/form-schema linear-wizard))
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(render-step [this {{:keys [snapshot step-params]} :multi-form-state :as request}] ...))
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```
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…plus the snapshot round-trip: the whole accumulating form state is serialized to hidden
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fields (custom EDN readers), then rebuilt every request by merging the posted pieces back
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into the snapshot (`:multi-form-state :snapshot` is read ~75× in `edit.clj`). The
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serialization needs custom readers, the merge is error-prone, and the payload grows each
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step.
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---
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## Single-step → plain form
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Two routes: `GET` (render) and `POST` (validate + save). State is plain form fields + an
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entity id. No snapshot, no server state, no protocol.
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```clojure
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{::route/edit (fn [req] (html-response (render-edit-form {:entity (get-entity req)})))
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::route/edit-submit (fn [req] (validate-and-save req))}
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```
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A `?mode=` toggle is just the `GET` re-rendering with a different query param — still a
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plain form. An add-row interaction is one extra `POST` that appends a fresh row and
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re-renders (the `+1` route).
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---
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## Genuinely multi-step → data-driven engine with session-stored step state
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> **Inspiration — Django `formtools` `WizardView`.** Django's wizard does *not* round-trip
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> a serialized blob of the whole form through the page. Each step's validated data is
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> written to a **storage backend (the user session by default)** under that step's key,
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> and the steps are combined only at the very end via `get_all_cleaned_data()`. We adopt
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> the same model: **replace the EDN snapshot + piecewise merging with per-step form state
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> stored in the Ring session.** A step writes its own data under its own key; nothing is
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> merged into a snapshot and nothing about other steps rides through the form.
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> Refs: `formtools.wizard.views.WizardView`, `SessionStorage`, `get_all_cleaned_data()`
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> (https://django-formtools.readthedocs.io/en/latest/wizard.html).
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A wizard is **data**:
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```clojure
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(def vendor-wizard-config
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{:steps [{:key :info :schema info-schema :fields [...] :render render-info-step
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:next (fn [data] :terms)}
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{:key :terms :schema terms-schema :fields [...] :render render-terms-step
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:next (fn [data] :done)}]
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:init-fn (fn [req] {...})
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:submit-route "/admin/vendor/wizard/submit"
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:done-fn (fn [all-data req] (save! all-data) (html-response "Saved"))})
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```
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with a tiny engine (no protocols) whose state lives **in the session**, keyed by a wizard
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instance id, each step's data under its own step key — the formtools `SessionStorage`
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model. No snapshot, no custom EDN readers, no merge-into-snapshot:
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```clojure
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;; Storage backed by the Ring session. Path: [:wizards <wizard-id> :step-data <step-key>]
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(defn create-wizard! [session config]
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(let [id (str (java.util.UUID/randomUUID))]
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[id (assoc-in session [:wizards id]
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{:current-step (-> config :steps first :key) :step-data {}})]))
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(defn put-step [session id k data] (assoc-in session [:wizards id :step-data k] data)) ; replace, not merge
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(defn set-step [session id k] (assoc-in session [:wizards id :current-step] k))
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(defn get-all [session id] (->> (get-in session [:wizards id :step-data]) vals (apply merge)))
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(defn forget [session id] (update session :wizards dissoc id))
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```
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The render emits only a **reference token** (`wizard-id`, `current-step`) in the form —
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never the form's state. The submit handler validates the posted step, `put-step`s it,
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computes `:next`, and either advances (`set-step`) or finishes (`get-all` + `:done-fn` +
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`forget`). Every fn returns the updated session for the handler to thread into the Ring
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response (`(assoc resp :session session')`).
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**Two routes per wizard:** open (`partial open-wizard config`) and submit
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(`partial handle-step-submit config`). State is namespaced by `wizard-id` inside the
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session, so multiple in-flight wizards (and browser tabs) don't collide, and it is
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discarded on completion (`forget`).
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### Storage lifetime (Open decision 1)
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State lives in the Ring session, scoped to true multi-step wizards (plain forms hold
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none). Lifetime follows the session; `forget` on completion prevents session bloat. For
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long-lived wizards, confirm the session backend (in-memory vs. durable) is acceptable or
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pick a durable store. **This engine is built in Phase 6** (Transaction Rule) — until then
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this file describes the target; validate `components/wizard_state.clj` +
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`components/wizard2.clj` against it when they land, and update this doc from the real
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implementation.
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