MEGA-BOQ-WEBAPP/README.md

# MEGA INFRA · BOQ Converter

Drop in **our** Candy PDF and **their** Excel. Get back their workbook
populated, using their own formulas and layout, plus a proof report of exactly
what was written, what was already correct, and where the two documents
disagree.

Anything you disagree with, you settle **in the app** and regenerate. The
consultant never has to leave the screen.

Runs entirely on your machine. Nothing is uploaded anywhere.

![the app](docs/app-screenshot.png)

## Settling a disagreement in the app

Where the two documents differ, the app writes **nothing** — your value stands.
Each dispute is one collapsed row. Open it and choose:

- **Keep yours (as it is)** — the default, your file is untouched
- **Use our PDF's value** — take the figure from the Candy export
- **or type a value** — anything else, coerced to a number when it looks like one

Press **Apply & regenerate** and the choices are written straight into the
workbook; the row then moves to "settled" and drops off the open list. The
PAYMENT column, your formulas and your formatting are never touched.

![disputes](docs/app-disputes.png)

## Design system — MEGA INFRASTRUCTURE

Palette sampled from the dashboard. All tokens live in **`static/theme.css`**
as CSS custom properties, so the brand can be retuned in one place without
touching Python.

| group | tokens |
|---|---|
| surfaces | `--canvas #1A202C` · `--topbar #1A212D` · `--surface #262A37` · `--surface-inset #252A36` · `--surface-raise #363B49` · `--hairline #2F3442` |
| status fills | `--success-fill #22383E` / `--success-edge #1B534A` · `--warn-fill #3A373C` · `--danger-fill #3A2D38` |
| accents | `--orange #FEA944` · `--orange-soft #F1A962` · `--orange-deep #DF8441` · `--green #00CD8A` · `--red #F04141` |
| text | `--text #E1E1E1` · `--text-muted #999999` · `--text-warm #B3AC99` · `--text-link #00CD8A` |

Warm neutrals are deliberate — `#E1E1E1` sits on a warm axis and pairs with
`#B3AC99`; pure `#EEEEEE` would read cold next to `#FEA944`.

**On the accessibility flag:** `#F04141` measures 3.77:1 on the card surface, so
it is used only for the severity edge and large marks. Any red *text* uses
`--red-soft #FF6B6B` at 5.15:1, which clears AA.

Type is **Fraunces** for headings and **Nunito** for body.

### Icons are real SVG, not emoji

Thirteen icons live in `boq_engine/theme.py` as inline SVG — 24x24, 1.75
stroke, round caps, so the set looks drawn by one hand. They inherit
`currentColor`, so they pick up the palette for free, and being inline they
need no network and no icon font.

They sit in the brand mark, the uploader labels, the KPI tiles, the pills and
the section headings — everywhere HTML actually renders.

**Not** on buttons or tab labels. Streamlit renders those as *plain text*, so
an inline SVG there leaks to the user as literal `<svg …>` markup, and emoji
read as emoticons. Those labels are deliberately typographic, which looks
more corporate anyway.

### Two implementation notes worth knowing

**The stylesheet is injected with `st.html`, not `st.markdown`.** Markdown
injection duplicated the style block on every rerun, and one malformed
selector silently killed every rule after it — the page rendered unstyled with
no error anywhere. Serving it from `static/` was tried and doesn't work:
Streamlit only serves its own hashed assets from that route, and an arbitrary
path falls through to the SPA shell and returns `index.html` as `text/html`.
`st.html` inserts the sheet into the page, isn't iframed, and replaces cleanly.

**Buttons and tab labels are plain text.** See the icon note above — this is
the one place Streamlit refuses to render HTML, and it fails loudly.

**Status messages are quiet pills, not alert blocks.** A filled
`st.warning` bar shouts at the reader for something that is background
information. `theme.pill()` sits at the same volume as the legend it belongs
next to. Genuine errors — source lines that have nowhere to go, subtotals that
do not reconcile — still use real alerts, because those are the thing to act on.

**Dispute choices are real Streamlit widgets.** Raw HTML `<select>` was tried
first and silently does nothing — the value never reaches Python, because
`st.markdown(unsafe_allow_html=True)` has no channel back to session state.
Keys are derived from the cell (`choice::<sheet>::<row>::<field>`) so a choice
survives a rerun and can be read back to build the override map.

## The rule that matters most

Where the two documents disagree, **the consultant's value is left alone and
the difference is reported.** The app never overwrites their work to match ours.

Every finding carries a `severity` decided in the data layer, not guessed from
the sentence text — so a red card always means "a person must choose":

| severity | meaning | on your sample |
|---|---|---|
| `decision` | the two documents genuinely disagree | **1** — overheads qty 15 000 vs 1 500 000 |
| `source_gap` | our PDF has no figure; theirs is better | 13 — all of Section 4 |
| `source_defect` | our PDF printed something corrupt | 2 — the `?` litre sign |
| `resolved` | the consultant settled it in the app | 0 until they do |
| `note` | worth knowing, no action implied | totals written |

A cell with an override is written instead of left alone, and the dispute drops
to `resolved` so it stops being flagged.

Two cases where that mattered:

- Candy prints the litre sign as `?`. Copying it into their file would have
  *introduced* a defect that was not there. Their `ℓ` was kept.
- Our PDF has all of Section 4 as "Rate only" (qty 0) — cable ducts and
  directional drilling were never quantified. Their template has real
  provisional quantities (100 m³ of trench, 200 m of 110 mm pipe, 70 m of
  drilling). Writing our `0` would have destroyed better data.

## Results on the sample

| | |
|---|---|
| Values written | 84 |
| Already correct (verified) | 98 |
| Source lines with nowhere to go | **0** |
| Disagreements reported, none overwritten | 16 |

Their workbook's own `COMBINED SUMMARY` recomputes to **R5,696,934.93** —
matching the Candy PDF's grand total to the cent, through their own formulas
and their own VAT line.

## Things the source BOQ gets wrong

Reported, not fixed — these are in the PDF:

1. **1.2 Scheduled Time-Related Items — R31,500.00 unexplained.** Its priced
   lines total R1,053,000.00 against a printed R1,084,500.00. Every other
   1.2.x line is blank/INCL. Worth a phone call.
2. **1.6 Temporary Works** — printed total swallows `1.5 Protection of Services`
   (R144,908.18), which the document numbers *after* it.
3. **2.1 Earthworks** — printed total swallows `2.2 Selected Sub Grade`
   (R146,983.50).
4. Item `4..2.5` (double dot), `2.5.4` used twice, two sections numbered
   `SECTION 6`, units drifting between `m2`/`m²`/`m3`/`m³`/`?`.

## Layout

```
static/theme.css         design tokens + all styling (edit this to retune)
.streamlit/config.toml   base Streamlit theme colours
boq_engine/extract.py    PDF -> tree            (deterministic, no model)
boq_engine/template.py   layout detect + align + write + totals
boq_engine/validate.py   arithmetic + structure checks
boq_engine/profiles.py   per-consultant template profiles
boq_engine/theme.py      injects the stylesheet, builds finding cards
boq_engine/populate.py   tree -> standalone xlsx + csv
app.py                   Streamlit UI
run.py                   CLI: PDF -> xlsx + csv
```

## How it handles a different template

Two real consultant workbooks have been run through it end to end:

| | Blueberry Square | Central Towers |
|---|---|---|
| source PDF | 11pp, 5 sections | 20pp, 18 sections |
| consultant workbook | 3 sheets, Candy-derived | **53 sheets, SANS 1200** |
| source total reproduced | R5,696,934.93 exact | R38,250,252.60 exact |
| lines written | 83 | 182 |
| already correct | 94 | 159 |
| **lines with no home** | **1 of 108** | **33 of 226** |
| consultant formulas destroyed | **0** | **0** |

What it takes to cope with a template nobody has seen before:

- **Item numbering.** Candy prints references three ways - `1.1.1`, `110....`,
  and a leading-dot `.01`. All are recognised. A running counter is rebuilt per
  section, because Candy restarts `.01` under every repeated heading while the
  consultant's template numbers them sequentially.
- **Wrapped headers.** A narrow column splits `QUANTITY` into `QUAN-` / `TITY`.
  Both header rows are read and joined, hyphen stripped, or the quantity column
  is simply never found.
- **The header lies.** On the SANS 1200 template the header advertises
  DESCRIPTION in column E while the text sits in D - and moves *within* one
  sheet. So the description is treated as whatever run of columns sits between
  ITEM and UNIT, not a single column.
- **Numbers are implied, not repeated.** A blank item cell still belongs to the
  number printed above it, so that is carried down. Without it two thirds of
  the rows read as unnumbered and nothing can match them.
- **The pool is cut to what matters.** Aligning against all 1314 rows of a
  53-sheet workbook makes the aligner cherry-pick; it is restricted to the
  sheets that own a section named in the source, leaving 499.

**The hard guarantee: the consultant's workbook is never damaged.** Every cell
that held a formula still holds it. A guard stops each write, and a final pass
re-reads the original and restores anything disturbed, so the promise is
checked rather than intended. On the SANS 1200 template, where quantities are
derived (`=G35`, `=CEILING.MATH(...)`), writing a literal over that would
destroy the engineer's model while looking like it worked.

## The download is gated

Nothing is offered for download until the **output file has been read back off
disk** and checked against the source. It does not trust what the writer
believes it did:

| check | fatal? | on Blueberry | on Central Towers |
|---|---|---|---|
| every formula the consultant had is still there | yes | 12 checked, 0 damaged | 3 633 checked, 0 damaged |
| no sheet went missing | yes | 3 → 3 | 53 → 53 |
| every write actually landed in the cell | yes | 70 of 70 | 225 of 225 |
| every source line accounted for | no | 107 of 108 | 193 of 226 |
| nothing replaced without a decision | no | 1 flagged | 6 flagged |
| the workbook's own arithmetic recomputes | no | R6 551 475.17 | R10 627 811.60 |

A failed fatal check **removes the download button** rather than showing a
warning somebody can scroll past. Recalculation needs LibreOffice; when it is
absent that check is skipped cleanly and the structural checks stand on their
own, which is why the container image does not carry it.

The **Verification** tab also shows, sheet by sheet, exactly what the app
decided about your columns — header row, item, description run, unit, quantity,
rate, amount. If a column is wrong you can see it and say so, instead of
wondering what the tool assumed.

## Known limits

- Central Towers coverage is **85%**, not 100%. The 33 unmatched lines are
  reported rather than written somewhere plausible, which is the safe failure —
  but it does mean that workbook is not finished. They cluster by section:
  200 (9), 143 (7), 141 (4), 142 (4), 146 (3), 110 (2), 190 (2), 170 (1),
  plus one `c)` sub-line. Sections 141–143 and 200 are where Candy's running
  `.01` counter still collides on the same number for genuinely different
  items, so those need a human to place.
- Column bands are tuned for A4 portrait Candy output. A different print layout
  needs `BANDS` in `extract.py` re-measured.
- The Central Towers workbook carries **external links** (`='[9]1200MF'!I56`).
  Those are preserved but will not resolve without the linked file.
- Description joins can drop a space where Candy's print engine split a word
  (`Fixed-ChargeItems`). Cosmetic.