---
phase: 08-oauth2-1-authorization-server
plan: 04
type: execute
wave: 4
depends_on: [08-03]
files_modified:
  - wristband/token.go
  - wristband/token_test.go
  - ../fonoteka.go/plugins/golem15/fonoteka/classes/auth/oauth_store.go
  - ../fonoteka.go/plugins/golem15/fonoteka/classes/auth/oauth_token_issuer.go
  - ../fonoteka.go/plugins/golem15/fonoteka/classes/auth/api_token_manager.go
autonomous: true
requirements: [AUTH-05, AUTH-06]
must_haves:
  truths:
    - "D-02: Token rejects JSON before ParseForm body-over-query parsing."
    - "D-04: S256/client-secret comparisons are constant-time and code replay has one winner."
    - "D-05: Wristband owns client authentication, PKCE verification, and atomic code exchange."
    - "D-11: Issued access tokens retain the configured inv_ prefix."
  artifacts:
    - path: "wristband/token.go"
      provides: "Client authentication and atomic authorization-code exchange"
  key_links:
    - from: "wristband/token.go"
      to: "oauth_token_issuer.go"
      via: "single transaction-bound Tx"
      pattern: "WithinTx"
---

<objective>
Complete one atomic authorization-code exchange for the assembled pending-request slice from 08-03.

Purpose: Prove token parsing, client authentication, constant-time PKCE, issuance, and code-replay rules before browser consent wiring.
Output: Token handler, issuer adapter, locked store transition, and deterministic/concurrent tests.
</objective>

<execution_context>
@/home/jin/.codex/get-shit-done/workflows/execute-plan.md
@/home/jin/.codex/get-shit-done/templates/summary.md
</execution_context>

<context>
@.planning/PROJECT.md
@.planning/ROADMAP.md
@.planning/STATE.md
@.planning/phases/08-oauth2-1-authorization-server/08-CONTEXT.md
@.planning/phases/08-oauth2-1-authorization-server/08-RESEARCH.md
@.planning/phases/08-oauth2-1-authorization-server/08-03-SUMMARY.md
</context>

<tasks>

<task type="auto" tdd="true">
  <name>Task 1: Specify atomic code exchange with executable RED tests</name>
  <files>wristband/token.go, wristband/token_test.go, ../fonoteka.go/plugins/golem15/fonoteka/classes/auth/oauth_store.go, ../fonoteka.go/plugins/golem15/fonoteka/classes/auth/oauth_token_issuer.go</files>
  <read_first>
    .planning/phases/08-oauth2-1-authorization-server/08-CONTEXT.md
    .planning/phases/08-oauth2-1-authorization-server/08-PATTERNS.md
    wristband/authorize.go
    wristband/stores.go
    ../fonoteka.go/plugins/golem15/fonoteka/classes/auth/api_token_manager.go
    ../fonoteka.go/plugins/golem15/fonoteka/classes/auth/token_guard.go
    /media/nvme/dev/golem15/fonoteka/plugins/golem15/fonoteka/controllers/api/OAuthTokenController.php
    /media/nvme/dev/golem15/fonoteka/plugins/golem15/fonoteka/classes/auth/OAuthCodeManager.php
    /media/nvme/dev/golem15/fonoteka/plugins/golem15/fonoteka/tests/functional/OAuthTokenTest.php
  </read_first>
  <behavior>
    - JSON rejection, ParseForm body-over-query precedence, Basic override, cache headers, exact challenge, and grant dispatch are tested.
    - S256 code/client/redirect/resource binding and synchronized one-winner replay are tested.
    - `TestPhase8RedCodeExchange` is the sole selected failure with `PHASE8_RED:code-exchange`.
  </behavior>
  <action>D-18: extend the existing interfaces with compiling token stubs and add deterministic unit plus real-store adapter tests. Validate exact package/test/sentinel through `check-phase8-red.sh go` and `go test -json`; cover T-08-PKCE, CODE-REPLAY, SECRET-TIMING, SCOPE-CEILING, and REQUEST-LEAK, including synchronized concurrent exchange. Every unexpected failing JSON action/package/test, build/setup/panic/no-test event, or missing/duplicate sentinel must fail the RED command.</action>
  <verify>
    <automated>scripts/check-phase8-red.sh go PHASE8_RED:code-exchange git.golem15.com/golem15/summercms/wristband TestPhase8RedCodeExchange -- go test -json ./wristband -run '^TestPhase8RedCodeExchange$' -count=1</automated>
  </verify>
  <acceptance_criteria>
    - The selected RED test compiles/runs and is the only test fail event; its package is the only package fail event and emits the exact sentinel once.
    - Tests assert exact status/body/no-newline, `Cache-Control: no-store`, `Pragma: no-cache`, and `Basic realm="OAuth"` only for invalid confidential client.
    - Synchronized exchange proves exactly one success and one `invalid_grant`; syntax/setup/panic/no-test or any unrelated failure is rejected.
  </acceptance_criteria>
  <done>The fail-closed RED suite specifies the full code-exchange contract without re-owning authorize behavior.</done>
</task>

<task type="auto" tdd="true">
  <name>Task 2: Implement atomic PKCE-bound code exchange</name>
  <files>wristband/token.go, wristband/token_test.go, ../fonoteka.go/plugins/golem15/fonoteka/classes/auth/oauth_store.go, ../fonoteka.go/plugins/golem15/fonoteka/classes/auth/oauth_token_issuer.go, ../fonoteka.go/plugins/golem15/fonoteka/classes/auth/api_token_manager.go</files>
  <read_first>
    wristband/token_test.go
    wristband/token.go
    wristband/crypto.go
    ../fonoteka.go/plugins/golem15/fonoteka/classes/auth/oauth_store.go
    ../fonoteka.go/plugins/golem15/fonoteka/classes/auth/api_token_manager.go
    ../fonoteka.go/plugins/golem15/fonoteka/models/api_token.go
    /media/nvme/dev/golem15/fonoteka/plugins/golem15/fonoteka/controllers/api/OAuthTokenController.php
    /media/nvme/dev/golem15/fonoteka/plugins/golem15/fonoteka/classes/auth/OAuthCodeManager.php
  </read_first>
  <behavior>
    - Token parsing/authentication precedes locked code lookup; code/client/redirect/resource/verifier bindings all match.
    - Code lock/consume, `inv_` access-token mint/stamp, and refresh creation commit atomically once.
  </behavior>
  <action>D-02: reject JSON before ParseForm, use body-over-query form values, and let Basic credentials override form credentials. D-03: apply configured code/access/refresh TTL and resource. D-04: compare fixed transforms with `subtle.ConstantTimeCompare`. D-05/D-06: keep grant policy and exact raw responses in wristband. D-07: lock/consume/mint/stamp/create refresh within one callback transaction. D-11: make the app issuer prefix config-backed while retaining exact `inv_`. D-17: run expired-only sweep on token entry. Preserve exact Basic challenge and cache headers.</action>
  <verify>
    <automated>go test ./wristband -run '^Test(Token|PKCE|Code)' -count=1 &amp;&amp; (cd ../fonoteka.go &amp;&amp; go test ./plugins/golem15/fonoteka/classes/auth -run '^TestOAuth(Code|Issuer)' -count=1)</automated>
  </verify>
  <acceptance_criteria>
    - Exact parser cases cover JSON rejection, body-over-query values, Basic-over-form credentials, unsupported/missing grant, public/confidential authentication, and challenge/no-challenge branches.
    - Correct verifier exchanges once for an `inv_` access token and refresh token with configured lifetimes; wrong verifier/client/redirect/resource and repeated code return exact native errors without minting.
    - Real-Postgres synchronized exchange has exactly one winner; persisted code is consumed and token/client/collection/scope bindings are correct, with no raw code/secret/verifier logged or stored.
  </acceptance_criteria>
  <done>One exact PKCE-bound code produces one inv_ access/refresh grant, and all validation/parser/replay failures are exact and tested.</done>
</task>

</tasks>

<threat_model>
## Trust Boundaries

| Boundary | Description |
|----------|-------------|
| Connector → authorize/token | Untrusted query/form/Basic input requests or redeems authority. |
| Tx → access-token store | One-time code state becomes durable credentials. |

## STRIDE Threat Register

| Threat ID | Category | Component | Disposition | Mitigation Plan |
|-----------|----------|-----------|-------------|-----------------|
| T-08-PKCE | Spoofing/Elevation | authorize/token | mitigate | Mandatory S256 syntax and constant-time comparison. |
| T-08-CODE-REPLAY | Spoofing | exchange | mitigate | Row lock, single transaction, concurrent one-winner test. |
| T-08-OPEN-REDIRECT | Spoofing/Disclosure | authorize | mitigate | Exact redirect validation before any redirect. |
| T-08-SECRET-TIMING | Information Disclosure | client auth | mitigate | Fixed transforms and constant-time compare. |
| T-08-SCOPE-CEILING | Elevation | authorize | mitigate | Requested ∩ client ceiling before persistence. |
| T-08-SC | Tampering | dependencies | mitigate | Standard library and existing app services only. |
</threat_model>

<verification>
- Focused wristband and issuer/store tests pass.
- Complete race execution is reserved exclusively for Plan 08-10's final blocking checkpoint.
</verification>

<success_criteria>
- Authorize and token protocol behavior is exact, concurrency-safe, and app-agnostic.
- The configured personal-token issuer produces the unchanged inv_ wire format.
</success_criteria>

<output>
Create `.planning/phases/08-oauth2-1-authorization-server/08-04-SUMMARY.md` when done.
</output>