Changeset df05838 for docs/P4-Prototype/PrototypeImplementation.md

Timestamp:

09/11/26 11:05:54 (3 weeks ago)

Author:

Stefan <trsunovstefan@…>

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main

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9577c79

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fe28254

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• docs/P4-Prototype/PrototypeImplementation.md (modified) (1 diff)

docs/P4-Prototype/PrototypeImplementation.md

@@ -1 @@
-# Prototype Implementation
+= Prototype Implementation =
 
-The prototype is a Go command-line application in `server/` that works against
-the `project` schema in PostgreSQL. It implements all seven use cases from
-[UseCaseModel](../P3-UseCaseModel/UseCaseModel.md) — the rubric requires at least three — with
-every database access shown as real, executed SQL. An auxiliary program in
-`bots/` simulates a live market so prices move while the prototype is running.
+The prototype is a Go command-line application in
+[https://github.com/StefanTrsunov/bp/tree/main/server server/] that works against the `project`
+schema in PostgreSQL. It implements all seven use cases from
+[https://github.com/StefanTrsunov/bp/blob/main/docs/P3-UseCaseModel/UseCaseModel.md UseCaseModel]
+– the rubric requires at least three – with every database access shown as real, executed SQL.
+An auxiliary program in [https://github.com/StefanTrsunov/bp/tree/main/bots bots/] simulates a
+live market so prices move while the prototype is running.
 
-Build, configure, run and test instructions: [BuildInstructions](BuildInstructions.md).
+Build, configure, run and test instructions:
+[https://github.com/StefanTrsunov/bp/blob/main/docs/P4-Prototype/BuildInstructions.md BuildInstructions].
 
-## Implemented use-cases
+All pages listed below, together with the screenshots of each run, are kept in the project's
+GitHub repository, [https://github.com/StefanTrsunov/bp StefanTrsunov/bp], under
+`docs/P4-Prototype/`.
 
-| Page | Use-case | Source |
-|------|----------|--------|
-| [UseCase0001Implementation](UseCase0001Implementation.md) | Register a new account | `server/auth.go` |
-| [UseCase0002Implementation](UseCase0002Implementation.md) | Log in | `server/auth.go` |
-| [UseCase0003Implementation](UseCase0003Implementation.md) | Deposit virtual funds | `server/account.go` |
-| [UseCase0004Implementation](UseCase0004Implementation.md) | Place market BUY order | `server/trade.go` |
-| [UseCase0005Implementation](UseCase0005Implementation.md) | Place market SELL order | `server/trade.go` |
-| [UseCase0006Implementation](UseCase0006Implementation.md) | View portfolio and history | `server/portfolio.go` |
-| [UseCase0007Implementation](UseCase0007Implementation.md) | Manage watchlist | `server/watchlist.go` |
+== Implemented use-cases ==
 
-Each page mirrors its P3 use-case page and adds the actual SQL emitted by the Go
-code plus a screenshot of the corresponding run against the live database.
+||=Page=||=Use-case=||=Source=||
+||[https://github.com/StefanTrsunov/bp/blob/main/docs/P4-Prototype/UseCase0001Implementation.md UseCase0001Implementation]||Register a new account||[https://github.com/StefanTrsunov/bp/blob/main/server/auth.go server/auth.go]||
+||[https://github.com/StefanTrsunov/bp/blob/main/docs/P4-Prototype/UseCase0002Implementation.md UseCase0002Implementation]||Log in||[https://github.com/StefanTrsunov/bp/blob/main/server/auth.go server/auth.go]||
+||[https://github.com/StefanTrsunov/bp/blob/main/docs/P4-Prototype/UseCase0003Implementation.md UseCase0003Implementation]||Deposit virtual funds||[https://github.com/StefanTrsunov/bp/blob/main/server/account.go server/account.go]||
+||[https://github.com/StefanTrsunov/bp/blob/main/docs/P4-Prototype/UseCase0004Implementation.md UseCase0004Implementation]||Place market BUY order||[https://github.com/StefanTrsunov/bp/blob/main/server/trade.go server/trade.go]||
+||[https://github.com/StefanTrsunov/bp/blob/main/docs/P4-Prototype/UseCase0005Implementation.md UseCase0005Implementation]||Place market SELL order||[https://github.com/StefanTrsunov/bp/blob/main/server/trade.go server/trade.go]||
+||[https://github.com/StefanTrsunov/bp/blob/main/docs/P4-Prototype/UseCase0006Implementation.md UseCase0006Implementation]||View portfolio and history||[https://github.com/StefanTrsunov/bp/blob/main/server/portfolio.go server/portfolio.go]||
+||[https://github.com/StefanTrsunov/bp/blob/main/docs/P4-Prototype/UseCase0007Implementation.md UseCase0007Implementation]||Manage watchlist||[https://github.com/StefanTrsunov/bp/blob/main/server/watchlist.go server/watchlist.go]||
 
-## What the prototype demonstrates about the database design
+Each page mirrors its P3 use-case page and adds the actual SQL emitted by the Go code plus a
+screenshot of the corresponding run against the live database. The screenshots are committed
+alongside the pages, in
+[https://github.com/StefanTrsunov/bp/tree/main/docs/P4-Prototype/screenshots docs/P4-Prototype/screenshots/].
 
-- **The current price is never stored as a column.** It is always the price of
-  the most recent row in `market_trades`, read through the `v_latest_prices`
-  view. Both the user's own fills and the bot's simulated trades feed the same
-  table, so there is exactly one definition of "the price".
-- **Money movements are transactional.** Buying touches five tables — `orders`,
-  `users`, `holdings`, `transactions`, `market_trades` — inside one transaction.
-  A failed balance check rolls the whole thing back: after a rejected purchase
-  there is no order row, no ledger entry and no holding. This is verified in the
-  failure-path tests in [BuildInstructions](BuildInstructions.md).
-- **Constraints do real work.** `UNIQUE (user_id, crypto_id)` on `holdings` is
-  what makes the `INSERT … ON CONFLICT DO UPDATE` upsert possible, so the
-  weighted-average entry price is recomputed by the database in one statement
-  instead of by a read-modify-write in application code.
-- **No identifiers are ever typed.** Markets are listed with their prices before
-  any choice is made, and everything else is selected by symbol.
+== What the prototype demonstrates about the database design ==
 
-## Known limitations
+ * '''The current price is never stored as a column.''' It is always the price of the most recent
+   row in `market_trades`, read through the `v_latest_prices` view. Both the user's own fills and
+   the bot's simulated trades feed the same table, so there is exactly one definition of "the
+   price".
+ * '''Money movements are transactional.''' Buying touches five tables – `orders`, `users`,
+   `holdings`, `transactions`, `market_trades` – inside one transaction. A failed balance check
+   rolls the whole thing back: after a rejected purchase there is no order row, no ledger entry
+   and no holding. This is verified in the failure-path tests in
+   [https://github.com/StefanTrsunov/bp/blob/main/docs/P4-Prototype/BuildInstructions.md BuildInstructions].
+ * '''Constraints do real work.''' `UNIQUE (user_id, crypto_id)` on `holdings` is what makes the
+   `INSERT … ON CONFLICT DO UPDATE` upsert possible, so the weighted-average entry price is
+   recomputed by the database in one statement instead of by a read-modify-write in application
+   code.
+ * '''No identifiers are ever typed.''' Markets are listed with their prices before any choice is
+   made, and everything else is selected by symbol.
 
-Deliberately out of scope for a first prototype, and the natural content of the
-later phases:
+== Known limitations ==
 
-- Only `market` orders execute. `limit` is accepted by the schema
-  (`orders.type`) but the matching logic is not implemented.
-- Passwords are SHA-256 without a salt. Adequate to demonstrate that the
-  password itself is never stored; not adequate for real use. A proper
-  password hash belongs in P9 (security).
-- Money is handled as `float64` in Go while the database columns are `numeric`.
-  All arithmetic that must be exact — the weighted average — is done in SQL for
-  that reason, but the Go side would need a decimal type for real use.
-- There is no connection pooling configuration and no explicit isolation level;
-  both are P8 topics.
+Deliberately out of scope for a first prototype, and the natural content of the later phases:
+
+ * Only `market` orders execute. `limit` is accepted by the schema (`orders.type`) but the
+   matching logic is not implemented.
+ * Passwords are SHA-256 without a salt. Adequate to demonstrate that the password itself is
+   never stored; not adequate for real use. A proper password hash belongs in P9 (security).
+ * Money is handled as `float64` in Go while the database columns are `numeric`. All arithmetic
+   that must be exact – the weighted average – is done in SQL for that reason, but the Go side
+   would need a decimal type for real use.
+ * There is no connection pooling configuration and no explicit isolation level; both are P8
+   topics.
+== AI usage ==
+
+AI was used in this phase and is logged in full, per the course rule for P1 onward.
+
+ * '''Phase log:'''
+   [https://github.com/StefanTrsunov/bp/blob/main/docs/P3-UseCaseModel/UseCaseModelAIUsage.md UseCaseModelAIUsage.md]
+   – service used, what the AI produced, and what I decided myself.
+ * '''Full conversation transcript:'''
+   [https://github.com/StefanTrsunov/bp/blob/main/docs/P1-ConceptualModel/ERModelAIUsage.md ERModelAIUsage.md]
+   – the same conversation produced the P1–P4 artefacts, so the complete prompt/response log is
+   kept in one place. Direct links:
+   [https://github.com/StefanTrsunov/bp/blob/main/docs/P1-ConceptualModel/ERModelAIUsage.md#session-1--2026-04-21 Session 1 – 2026-04-21],
+   [https://github.com/StefanTrsunov/bp/blob/main/docs/P1-ConceptualModel/ERModelAIUsage.md#session-2--2026-08-06--2026-08-07 Session 2 – 2026-08-06/07].
+
+'''Service:''' Claude Code (Anthropic), https://claude.com/claude-code – Claude subscription,
+model Claude Opus 4.7 (1M context).
+
+'''In short:''' the AI proposed the actor taxonomy and drafted the seven use cases with their SQL
+in session 1. In session 2 the use-case model itself was '''not''' changed – the only work was
+re-executing every scenario, including the failure paths, against a live PostgreSQL 16 database.
+
+== AI usage ==
+
+AI was used in this phase and is logged in full, per the course rule for P1 onward.
+
+ * '''Phase log:'''
+   [https://github.com/StefanTrsunov/bp/blob/main/docs/P4-Prototype/PrototypeImplementationAIUsage.md PrototypeImplementationAIUsage.md]
+   – service used, the bugs found and fixed, the test evidence, and what I decided myself.
+ * '''Full conversation transcript:'''
+   [https://github.com/StefanTrsunov/bp/blob/main/docs/P1-ConceptualModel/ERModelAIUsage.md ERModelAIUsage.md]
+   – the same conversation produced the P1–P4 artefacts, so the complete prompt/response log is
+   kept in one place. Direct links:
+   [https://github.com/StefanTrsunov/bp/blob/main/docs/P1-ConceptualModel/ERModelAIUsage.md#session-1--2026-04-21 Session 1 – 2026-04-21],
+   [https://github.com/StefanTrsunov/bp/blob/main/docs/P1-ConceptualModel/ERModelAIUsage.md#session-2--2026-08-06--2026-08-07 Session 2 – 2026-08-06/07].
+
+'''Service:''' Claude Code (Anthropic), https://claude.com/claude-code – Claude subscription,
+model Claude Opus 4.7 (1M context).
+
+'''In short:''' session 1 rewrote the existing Chi/HTTP backend as the CLI prototype covering
+UC0001–UC0007 and added the market bot. Session 2 was a review pass I asked for, which found and
+fixed three bugs – a path-resolution bug that made the documented build instructions fail, an
+infinite loop at end of input, and an error check in the wrong order that misreported database
+failures as "Insufficient holding" – and replaced the read-modify-write holding update with a
+single `INSERT … ON CONFLICT DO UPDATE`.