# Rust-Side Lineloss XLSX Export Implementation Plan

> **For agentic workers:** REQUIRED SUB-SKILL: Use superpowers:subagent-driven-development (recommended) or superpowers:executing-plans to implement this plan task-by-task. Steps use checkbox (`- [ ]`) syntax for tracking.

**Goal:** Move XLSX export from browser JS (blocked by CORS) to Rust side, so `collect_lineloss.js` only collects data and Rust generates the `.xlsx` file locally.

**Architecture:** JS collects API data and returns a `report-artifact` JSON with `rows`, `column_defs`, and metadata. Rust parses the artifact, extracts rows + column definitions, and generates a standard `.xlsx` file using the `zip` crate + OpenXML XML strings (same pattern as `openxml_office_tool.rs`). Report log is deferred.

**Tech Stack:** Rust, `zip` 0.6.6, `serde_json`, OpenXML Spreadsheet ML, JavaScript (browser-injected)

**Spec:** `docs/superpowers/specs/2026-04-13-rust-side-lineloss-xlsx-export.md`

---

## File Structure

| File | Responsibility |
|------|---------------|
| `src/compat/lineloss_xlsx_export.rs` | **New.** Pure XLSX generation: takes column defs + row data, produces `.xlsx` file. No business logic. |
| `src/compat/deterministic_submit.rs` | **Modify.** After receiving JS artifact, extract rows + column_defs, call XLSX export, attach path to outcome. |
| `src/compat/mod.rs` | **Modify.** Register `lineloss_xlsx_export` module. |
| `D:/data/ideaSpace/rust/sgClaw/claw/claw/skills/skill_staging/skills/tq-lineloss-report/scripts/collect_lineloss.js` | **Modify.** Remove `exportWorkbook`/`writeReportLog` calls. Add `column_defs` to artifact. |
| `tests/lineloss_xlsx_export_test.rs` | **New.** Unit tests for XLSX generation. |

---

### Task 1: Create `lineloss_xlsx_export.rs` with Tests

**Files:**
- Create: `src/compat/lineloss_xlsx_export.rs`
- Create: `tests/lineloss_xlsx_export_test.rs`
- Modify: `src/compat/mod.rs`

- [ ] **Step 1: Register the new module in `src/compat/mod.rs`**

Add the module declaration in alphabetical order. In `src/compat/mod.rs`, insert after `pub mod event_bridge;`:

```rust
pub mod lineloss_xlsx_export;
```

The full file becomes:

```rust
pub mod artifact_open;
pub mod browser_script_skill_tool;
pub mod browser_tool_adapter;
pub mod config_adapter;
pub mod cron_adapter;
pub mod deterministic_submit;
pub mod direct_skill_runtime;
pub mod event_bridge;
pub mod lineloss_xlsx_export;
pub mod memory_adapter;
pub mod openxml_office_tool;
pub mod orchestration;
pub mod runtime;
pub mod screen_html_export_tool;
pub mod tq_lineloss;
pub mod workflow_executor;
```

- [ ] **Step 2: Write the failing test for XLSX generation**

Create `tests/lineloss_xlsx_export_test.rs`:

```rust
use std::fs;
use std::path::PathBuf;

use serde_json::json;
use sgclaw::compat::lineloss_xlsx_export::{export_lineloss_xlsx, LinelossExportRequest};

fn temp_output_path(name: &str) -> PathBuf {
    let dir = std::env::temp_dir().join("sgclaw-test-xlsx");
    fs::create_dir_all(&dir).unwrap();
    dir.join(name)
}

#[test]
fn export_month_lineloss_produces_valid_xlsx() {
    let output_path = temp_output_path("month-test.xlsx");
    if output_path.exists() {
        fs::remove_file(&output_path).unwrap();
    }

    let request = LinelossExportRequest {
        sheet_name: "国网兰州供电公司月度线损分析报表(2026-03)".to_string(),
        column_defs: vec![
            ("ORG_NAME".to_string(), "供电单位".to_string()),
            ("YGDL".to_string(), "累计供电量".to_string()),
            ("YYDL".to_string(), "累计售电量".to_string()),
            ("YXSL".to_string(), "线损完成率(%)".to_string()),
            ("RAT_SCOPE".to_string(), "线损率累计目标值".to_string()),
            ("BLANK3".to_string(), "目标完成率".to_string()),
            ("BLANK2".to_string(), "排行".to_string()),
        ],
        rows: vec![
            serde_json::from_value(json!({
                "ORG_NAME": "城关供电",
                "YGDL": "12345.67",
                "YYDL": "11234.56",
                "YXSL": "9.00",
                "RAT_SCOPE": "9.50",
                "BLANK3": "94.74",
                "BLANK2": "1"
            }))
            .unwrap(),
            serde_json::from_value(json!({
                "ORG_NAME": "七里河供电",
                "YGDL": "9876.54",
                "YYDL": "8765.43",
                "YXSL": "11.24",
                "RAT_SCOPE": "10.00",
                "BLANK3": "112.40",
                "BLANK2": "2"
            }))
            .unwrap(),
        ],
        output_path: output_path.clone(),
    };

    let result_path = export_lineloss_xlsx(&request).unwrap();
    assert_eq!(result_path, output_path);
    assert!(output_path.exists());

    // Verify it's a valid ZIP (xlsx is a zip archive)
    let file = fs::File::open(&output_path).unwrap();
    let mut archive = zip::ZipArchive::new(file).unwrap();

    // Must contain the standard OpenXML entries
    let entry_names: Vec<String> = (0..archive.len())
        .map(|i| archive.by_index(i).unwrap().name().to_string())
        .collect();

    assert!(entry_names.contains(&"[Content_Types].xml".to_string()));
    assert!(entry_names.contains(&"xl/worksheets/sheet1.xml".to_string()));
    assert!(entry_names.contains(&"xl/workbook.xml".to_string()));

    // Read sheet1.xml and verify it contains our data
    let mut sheet = archive.by_name("xl/worksheets/sheet1.xml").unwrap();
    let mut xml = String::new();
    std::io::Read::read_to_string(&mut sheet, &mut xml).unwrap();

    assert!(xml.contains("供电单位"), "header row should contain 供电单位");
    assert!(xml.contains("累计供电量"), "header row should contain 累计供电量");
    assert!(xml.contains("城关供电"), "data should contain 城关供电");
    assert!(xml.contains("12345.67"), "data should contain 12345.67");
    assert!(xml.contains("七里河供电"), "data should contain second row");

    // Cleanup
    fs::remove_file(&output_path).unwrap();
}

#[test]
fn export_empty_rows_returns_error() {
    let output_path = temp_output_path("empty-test.xlsx");

    let request = LinelossExportRequest {
        sheet_name: "test".to_string(),
        column_defs: vec![("A".to_string(), "ColA".to_string())],
        rows: vec![],
        output_path: output_path.clone(),
    };

    let result = export_lineloss_xlsx(&request);
    assert!(result.is_err());
    assert!(
        result.unwrap_err().to_string().contains("rows must not be empty"),
        "should reject empty rows"
    );
}
```

- [ ] **Step 3: Run the test to verify it fails**

Run: `cargo test --test lineloss_xlsx_export_test -- --nocapture`

Expected: compilation error — `lineloss_xlsx_export` module doesn't exist yet or `export_lineloss_xlsx` / `LinelossExportRequest` not defined.

- [ ] **Step 4: Implement `src/compat/lineloss_xlsx_export.rs`**

```rust
use std::fs;
use std::io::Write;
use std::path::{Path, PathBuf};

use serde_json::{Map, Value};
use zip::write::FileOptions;
use zip::{CompressionMethod, ZipWriter};

pub struct LinelossExportRequest {
    pub sheet_name: String,
    pub column_defs: Vec<(String, String)>,
    pub rows: Vec<Map<String, Value>>,
    pub output_path: PathBuf,
}

pub fn export_lineloss_xlsx(request: &LinelossExportRequest) -> anyhow::Result<PathBuf> {
    if request.rows.is_empty() {
        anyhow::bail!("rows must not be empty");
    }
    if request.column_defs.is_empty() {
        anyhow::bail!("column_defs must not be empty");
    }

    let sheet_xml = build_worksheet_xml(&request.column_defs, &request.rows);

    write_xlsx(
        &request.output_path,
        &request.sheet_name,
        &sheet_xml,
    )?;

    Ok(request.output_path.clone())
}

fn build_worksheet_xml(
    column_defs: &[(String, String)],
    rows: &[Map<String, Value>],
) -> String {
    let mut xml_rows = Vec::with_capacity(rows.len() + 1);

    // Header row (row 1)
    let header_cells: Vec<String> = column_defs
        .iter()
        .enumerate()
        .map(|(col_idx, (_key, label))| {
            let col_letter = column_letter(col_idx);
            format!(
                "<c r=\"{col_letter}1\" t=\"inlineStr\"><is><t>{}</t></is></c>",
                xml_escape(label)
            )
        })
        .collect();
    xml_rows.push(format!("<row r=\"1\">{}</row>", header_cells.join("")));

    // Data rows (row 2+)
    for (row_idx, row) in rows.iter().enumerate() {
        let excel_row = row_idx + 2;
        let cells: Vec<String> = column_defs
            .iter()
            .enumerate()
            .map(|(col_idx, (key, _label))| {
                let col_letter = column_letter(col_idx);
                let value = row
                    .get(key)
                    .map(|v| value_to_string(v))
                    .unwrap_or_default();
                format!(
                    "<c r=\"{col_letter}{excel_row}\" t=\"inlineStr\"><is><t>{}</t></is></c>",
                    xml_escape(&value)
                )
            })
            .collect();
        xml_rows.push(format!("<row r=\"{excel_row}\">{}</row>", cells.join("")));
    }

    format!(
        "<?xml version=\"1.0\" encoding=\"UTF-8\" standalone=\"yes\"?>\
<worksheet xmlns=\"http://schemas.openxmlformats.org/spreadsheetml/2006/main\">\
<sheetData>{}</sheetData>\
</worksheet>",
        xml_rows.join("")
    )
}

fn column_letter(index: usize) -> String {
    let mut result = String::new();
    let mut n = index;
    loop {
        result.insert(0, (b'A' + (n % 26) as u8) as char);
        if n < 26 {
            break;
        }
        n = n / 26 - 1;
    }
    result
}

fn value_to_string(value: &Value) -> String {
    match value {
        Value::String(text) => text.clone(),
        Value::Number(number) => number.to_string(),
        Value::Bool(flag) => flag.to_string(),
        Value::Null => String::new(),
        other => other.to_string(),
    }
}

fn xml_escape(value: &str) -> String {
    value
        .replace('&', "&amp;")
        .replace('<', "&lt;")
        .replace('>', "&gt;")
}

fn write_xlsx(output_path: &Path, sheet_name: &str, sheet_xml: &str) -> anyhow::Result<()> {
    if let Some(parent) = output_path.parent() {
        fs::create_dir_all(parent)?;
    }
    if output_path.exists() {
        fs::remove_file(output_path)?;
    }

    let file = fs::File::create(output_path)?;
    let mut zip = ZipWriter::new(file);
    let options = FileOptions::default().compression_method(CompressionMethod::Stored);

    zip.start_file("[Content_Types].xml", options)?;
    zip.write_all(content_types_xml().as_bytes())?;

    zip.start_file("_rels/.rels", options)?;
    zip.write_all(root_rels_xml().as_bytes())?;

    zip.start_file("docProps/app.xml", options)?;
    zip.write_all(app_xml().as_bytes())?;

    zip.start_file("docProps/core.xml", options)?;
    zip.write_all(core_xml().as_bytes())?;

    zip.start_file("xl/workbook.xml", options)?;
    zip.write_all(workbook_xml(&xml_escape(sheet_name)).as_bytes())?;

    zip.start_file("xl/_rels/workbook.xml.rels", options)?;
    zip.write_all(workbook_rels_xml().as_bytes())?;

    zip.start_file("xl/worksheets/sheet1.xml", options)?;
    zip.write_all(sheet_xml.as_bytes())?;

    zip.finish()?;
    Ok(())
}

fn content_types_xml() -> &'static str {
    r#"<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<Types xmlns="http://schemas.openxmlformats.org/package/2006/content-types">
  <Default Extension="rels" ContentType="application/vnd.openxmlformats-package.relationships+xml"/>
  <Default Extension="xml" ContentType="application/xml"/>
  <Override PartName="/xl/workbook.xml" ContentType="application/vnd.openxmlformats-officedocument.spreadsheetml.sheet.main+xml"/>
  <Override PartName="/xl/worksheets/sheet1.xml" ContentType="application/vnd.openxmlformats-officedocument.spreadsheetml.worksheet+xml"/>
  <Override PartName="/docProps/core.xml" ContentType="application/vnd.openxmlformats-package.core-properties+xml"/>
  <Override PartName="/docProps/app.xml" ContentType="application/vnd.openxmlformats-officedocument.extended-properties+xml"/>
</Types>"#
}

fn root_rels_xml() -> &'static str {
    r#"<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<Relationships xmlns="http://schemas.openxmlformats.org/package/2006/relationships">
  <Relationship Id="rId1" Type="http://schemas.openxmlformats.org/officeDocument/2006/relationships/officeDocument" Target="xl/workbook.xml"/>
  <Relationship Id="rId2" Type="http://schemas.openxmlformats.org/package/2006/relationships/metadata/core-properties" Target="docProps/core.xml"/>
  <Relationship Id="rId3" Type="http://schemas.openxmlformats.org/officeDocument/2006/relationships/extended-properties" Target="docProps/app.xml"/>
</Relationships>"#
}

fn app_xml() -> &'static str {
    r#"<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<Properties xmlns="http://schemas.openxmlformats.org/officeDocument/2006/extended-properties"
            xmlns:vt="http://schemas.openxmlformats.org/officeDocument/2006/docPropsVTypes">
  <Application>sgClaw</Application>
</Properties>"#
}

fn core_xml() -> &'static str {
    r#"<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<cp:coreProperties xmlns:cp="http://schemas.openxmlformats.org/package/2006/metadata/core-properties"
                   xmlns:dc="http://purl.org/dc/elements/1.1/"
                   xmlns:dcterms="http://purl.org/dc/terms/"
                   xmlns:dcmitype="http://purl.org/dc/dcmitype/"
                   xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
  <dc:title>台区线损报表</dc:title>
</cp:coreProperties>"#
}

fn workbook_xml(sheet_name: &str) -> String {
    format!(
        r#"<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<workbook xmlns="http://schemas.openxmlformats.org/spreadsheetml/2006/main"
          xmlns:r="http://schemas.openxmlformats.org/officeDocument/2006/relationships">
  <sheets>
    <sheet name="{sheet_name}" sheetId="1" r:id="rId1"/>
  </sheets>
</workbook>"#
    )
}

fn workbook_rels_xml() -> &'static str {
    r#"<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<Relationships xmlns="http://schemas.openxmlformats.org/package/2006/relationships">
  <Relationship Id="rId1" Type="http://schemas.openxmlformats.org/officeDocument/2006/relationships/worksheet" Target="worksheets/sheet1.xml"/>
</Relationships>"#
}

#[cfg(test)]
mod tests {
    use super::column_letter;

    #[test]
    fn column_letter_maps_indices_correctly() {
        assert_eq!(column_letter(0), "A");
        assert_eq!(column_letter(1), "B");
        assert_eq!(column_letter(6), "G");
        assert_eq!(column_letter(25), "Z");
        assert_eq!(column_letter(26), "AA");
    }
}
```

- [ ] **Step 5: Run the tests to verify they pass**

Run: `cargo test --test lineloss_xlsx_export_test -- --nocapture`

Expected: both `export_month_lineloss_produces_valid_xlsx` and `export_empty_rows_returns_error` PASS.

Also run the internal unit test:

Run: `cargo test lineloss_xlsx_export -- --nocapture`

Expected: `column_letter_maps_indices_correctly` PASS.

- [ ] **Step 6: Commit**

```bash
git add src/compat/lineloss_xlsx_export.rs src/compat/mod.rs tests/lineloss_xlsx_export_test.rs
git commit -m "feat(lineloss): add Rust-side XLSX generation for lineloss reports"
```

---

### Task 2: Integrate XLSX Export into `deterministic_submit.rs`

**Files:**
- Modify: `src/compat/deterministic_submit.rs`

- [ ] **Step 1: Add imports and helper function to extract export data from artifact**

At the top of `src/compat/deterministic_submit.rs`, add the import:

```rust
use crate::compat::lineloss_xlsx_export::{export_lineloss_xlsx, LinelossExportRequest};
```

Then add a new helper function after `summarize_lineloss_artifact`:

```rust
struct LinelossArtifactExportData {
    sheet_name: String,
    column_defs: Vec<(String, String)>,
    rows: Vec<Map<String, Value>>,
}

fn extract_export_data(output: &str) -> Option<LinelossArtifactExportData> {
    let payload: Value = serde_json::from_str(output).ok()?;
    let artifact = payload
        .as_object()
        .and_then(|object| object.get("text"))
        .unwrap_or(&payload);
    let artifact = artifact.as_object()?;

    if artifact.get("type").and_then(Value::as_str) != Some("report-artifact") {
        return None;
    }

    let status = artifact.get("status").and_then(Value::as_str).unwrap_or("");
    if !matches!(status, "ok" | "partial") {
        return None;
    }

    let rows = artifact
        .get("rows")
        .and_then(Value::as_array)?;
    if rows.is_empty() {
        return None;
    }
    let rows: Vec<Map<String, Value>> = rows
        .iter()
        .filter_map(|row| row.as_object().cloned())
        .collect();
    if rows.is_empty() {
        return None;
    }

    let column_defs: Vec<(String, String)> = artifact
        .get("column_defs")
        .and_then(Value::as_array)
        .map(|defs| {
            defs.iter()
                .filter_map(|def| {
                    let arr = def.as_array()?;
                    let key = arr.first()?.as_str()?.to_string();
                    let label = arr.get(1)?.as_str()?.to_string();
                    Some((key, label))
                })
                .collect()
        })
        .unwrap_or_default();

    // Fallback: if column_defs not in artifact, try "columns" array as keys
    let column_defs = if column_defs.is_empty() {
        let columns = artifact
            .get("columns")
            .and_then(Value::as_array)?;
        columns
            .iter()
            .filter_map(|col| {
                let key = col.as_str()?.to_string();
                Some((key.clone(), key))
            })
            .collect()
    } else {
        column_defs
    };

    if column_defs.is_empty() {
        return None;
    }

    let org_label = artifact
        .get("org")
        .and_then(Value::as_object)
        .and_then(|org| org.get("label"))
        .and_then(Value::as_str)
        .unwrap_or("lineloss");
    let period_mode = artifact
        .get("period")
        .and_then(Value::as_object)
        .and_then(|p| p.get("mode"))
        .and_then(Value::as_str)
        .unwrap_or("month");
    let period_value = artifact
        .get("period")
        .and_then(Value::as_object)
        .and_then(|p| p.get("value"))
        .and_then(Value::as_str)
        .unwrap_or("");
    let mode_label = if period_mode == "week" { "周度" } else { "月度" };
    let sheet_name = format!("{org_label}{mode_label}线损分析报表({period_value})");

    Some(LinelossArtifactExportData {
        sheet_name,
        column_defs,
        rows,
    })
}
```

- [ ] **Step 2: Add the export-after-collection function**

Add a new function that wraps the existing flow with XLSX export:

```rust
fn try_export_lineloss_xlsx(
    output: &str,
    workspace_root: &Path,
) -> Option<PathBuf> {
    let data = extract_export_data(output)?;
    let nanos = std::time::SystemTime::now()
        .duration_since(std::time::UNIX_EPOCH)
        .map(|d| d.as_nanos())
        .unwrap_or_default();
    let out_dir = workspace_root.join("out");
    let output_path = out_dir.join(format!("tq-lineloss-{nanos}.xlsx"));

    let request = LinelossExportRequest {
        sheet_name: data.sheet_name,
        column_defs: data.column_defs,
        rows: data.rows,
        output_path,
    };

    match export_lineloss_xlsx(&request) {
        Ok(path) => {
            eprintln!("[deterministic_submit] XLSX exported to: {}", path.display());
            Some(path)
        }
        Err(err) => {
            eprintln!("[deterministic_submit] XLSX export failed: {err}");
            None
        }
    }
}
```

- [ ] **Step 3: Modify `execute_deterministic_submit_with_browser_backend` to call export**

Replace the body of `execute_deterministic_submit_with_browser_backend` (lines 119-136 of the original file):

```rust
pub fn execute_deterministic_submit_with_browser_backend(
    browser_backend: Arc<dyn BrowserBackend>,
    plan: &DeterministicExecutionPlan,
    workspace_root: &Path,
    settings: &SgClawSettings,
) -> Result<DirectSubmitOutcome, PipeError> {
    let args = deterministic_submit_args(plan);
    let output =
        crate::compat::direct_skill_runtime::execute_browser_script_skill_raw_output_with_browser_backend(
            browser_backend,
            &plan.tool_name,
            workspace_root,
            settings,
            args,
        )?;

    let export_path = try_export_lineloss_xlsx(&output, workspace_root);
    Ok(summarize_lineloss_output_with_export(&output, export_path.as_deref()))
}
```

Apply the same change to `execute_deterministic_submit` (the non-backend variant, lines 101-117):

```rust
pub fn execute_deterministic_submit<T: Transport + 'static>(
    browser_tool: BrowserPipeTool<T>,
    plan: &DeterministicExecutionPlan,
    workspace_root: &Path,
    settings: &SgClawSettings,
) -> Result<DirectSubmitOutcome, PipeError> {
    let args = deterministic_submit_args(plan);
    let output = crate::compat::direct_skill_runtime::execute_browser_script_skill_raw_output(
        browser_tool,
        &plan.tool_name,
        workspace_root,
        settings,
        args,
    )?;

    let export_path = try_export_lineloss_xlsx(&output, workspace_root);
    Ok(summarize_lineloss_output_with_export(&output, export_path.as_deref()))
}
```

- [ ] **Step 4: Add `summarize_lineloss_output_with_export` function**

Add this new function. It wraps the existing `summarize_lineloss_output` and appends the export path:

```rust
fn summarize_lineloss_output_with_export(output: &str, export_path: Option<&Path>) -> DirectSubmitOutcome {
    let mut outcome = summarize_lineloss_output(output);

    if let Some(path) = export_path {
        outcome.summary.push_str(&format!(" export_path={}", path.display()));
    }

    outcome
}
```

- [ ] **Step 5: Run existing tests to ensure nothing breaks**

Run: `cargo test --test deterministic_submit_test -- --nocapture`

Expected: all existing tests PASS (the tests don't call `execute_deterministic_submit`, they test `decide_deterministic_submit` and parsing logic which is unchanged).

Run: `cargo test deterministic_submit -- --nocapture`

Expected: PASS.

- [ ] **Step 6: Commit**

```bash
git add src/compat/deterministic_submit.rs
git commit -m "feat(lineloss): integrate Rust-side XLSX export into deterministic submit pipeline"
```

---

### Task 3: Modify `collect_lineloss.js` to Skip Browser-Side Export

**Files:**
- Modify: `D:/data/ideaSpace/rust/sgClaw/claw/claw/skills/skill_staging/skills/tq-lineloss-report/scripts/collect_lineloss.js`

- [ ] **Step 1: Add `column_defs` to the artifact returned by `buildArtifact`**

In the `buildArtifact` function (around line 198), the `columns` field currently contains just column keys (e.g., `["ORG_NAME", "YGDL", ...]`). Add a `column_defs` field that includes the full key+label pairs. Change the `buildArtifact` function to also accept and emit `column_defs`:

Find this block in `buildArtifact` (line 198-242):

```javascript
function buildArtifact({
  status,
  blockedReason = '',
  fatalError = '',
  org_label = '',
  org_code = '',
  period_mode = '',
  period_mode_code = '',
  period_value = '',
  period_payload = {},
  columns = [],
  rows = [],
  export: exportState,
  reasons = []
}) {
```

Replace with:

```javascript
function buildArtifact({
  status,
  blockedReason = '',
  fatalError = '',
  org_label = '',
  org_code = '',
  period_mode = '',
  period_mode_code = '',
  period_value = '',
  period_payload = {},
  columns = [],
  column_defs = [],
  rows = [],
  export: exportState,
  reasons = []
}) {
```

In the returned object (the `return { ... }` block inside `buildArtifact`), add `column_defs` after `columns`:

```javascript
    columns: [...columns],
    column_defs: [...column_defs],
    rows: [...rows],
```

- [ ] **Step 2: Pass `column_defs` from `buildBrowserEntrypointResult`**

In `buildBrowserEntrypointResult`, after the `columns` assignment (around line 452), add:

```javascript
  const columns = normalizedArgs.period_mode === 'week' ? WEEK_COLUMNS : MONTH_COLUMNS;
  const columnDefs = normalizedArgs.period_mode === 'week' ? WEEK_COLUMN_DEFS : MONTH_COLUMN_DEFS;
```

Then in every call to `buildArtifact` inside `buildBrowserEntrypointResult`, add `column_defs: columnDefs` alongside `columns`. There are 5 calls:

**Call 1** (API error, around line 466):
```javascript
      columns,
      column_defs: columnDefs,
      rows: [],
```

**Call 2** (empty rows, around line 483):
```javascript
      columns,
      column_defs: columnDefs,
      rows: []
```

**Call 3** (normalization failure, around line 497):
```javascript
      columns,
      column_defs: columnDefs,
      rows: [],
```

**Call 4** (success, around line 558):
```javascript
    columns,
    column_defs: columnDefs,
    rows,
```

Note: the two `buildArtifact` calls before the `columns` variable is assigned (validation failure and page context failure, around lines 422 and 439) don't need `column_defs` since they don't have data.

- [ ] **Step 3: Remove the `exportWorkbook` and `writeReportLog` calls from the success path**

In `buildBrowserEntrypointResult`, replace the entire export block (lines 518-556) with a simplified version:

Find:
```javascript
  const exportState = {
    attempted: false,
    status: 'skipped',
    message: null
  };

  if (typeof deps.exportWorkbook === 'function') {
    exportState.attempted = true;
    try {
      const exportPayload = buildExportPayload({
        mode: normalizedArgs.period_mode,
        orgLabel: normalizedArgs.org_label,
        periodValue: normalizedArgs.period_value,
        rows
      });
      const exportResult = await deps.exportWorkbook(exportPayload);
      const exportPath = pickFirstNonEmpty(exportResult?.path, exportResult?.data?.path, exportResult?.data?.data);
      if (!exportPath) {
        throw new Error('export_failed');
      }
      exportState.status = 'ok';
      exportState.message = exportPath;

      if (typeof deps.writeReportLog === 'function') {
        try {
          const reportLog = await deps.writeReportLog(buildReportName(normalizedArgs), exportPath);
          if (reportLog?.success === false) {
            reasons.push('report_log_failed');
          }
        } catch (_error) {
          reasons.push('report_log_failed');
        }
      }
    } catch (error) {
      reasons.push('export_failed');
      exportState.status = 'failed';
      exportState.message = pickFirstNonEmpty(error?.message, 'export_failed');
    }
  }
```

Replace with:
```javascript
  // Export is handled by Rust side after receiving the artifact.
  // JS only provides rows + column_defs in the artifact.
  const exportState = {
    attempted: false,
    status: 'deferred_to_rust',
    message: null
  };
```

- [ ] **Step 4: Remove unused constants and functions**

Remove these constants (lines 5-6) since they are no longer called from JS:

```javascript
const EXPORT_SERVICE_URL = 'http://localhost:13313/SurfaceServices/personalBread/export/faultDetailsExportXLSX';
const REPORT_LOG_URL = 'http://localhost:13313/ReportServices/Api/setReportLog';
```

Remove the `postJson` function (lines 264-294) — it is no longer needed since no JS-side HTTP calls are made to localhost.

Remove these functions from `defaultBrowserDeps()`:
- `exportWorkbook` (lines 350-373)
- `writeReportLog` (lines 375-409)

Remove these now-unused functions:
- `buildExportTitles` (lines 244-254)
- `buildExportPayload` (lines 256-262)
- `buildReportName` (lines 413-415)

- [ ] **Step 5: Update the module.exports to remove unused exports**

Update the `module.exports` block (lines 572-586). Remove `buildBrowserEntrypointResult` from exports if it was only used for testing with full deps, or keep it for test compatibility. The final exports block:

```javascript
if (typeof module !== 'undefined' && module.exports) {
  module.exports = {
    MONTH_COLUMNS,
    WEEK_COLUMNS,
    MONTH_COLUMN_DEFS,
    WEEK_COLUMN_DEFS,
    validateArgs,
    buildMonthRequest,
    buildWeekRequest,
    normalizeRows,
    determineArtifactStatus,
    buildArtifact,
    buildBrowserEntrypointResult
  };
} else {
  return buildBrowserEntrypointResult(args);
}
```

- [ ] **Step 6: Verify the JS file has no syntax errors**

Run: `node -c "D:/data/ideaSpace/rust/sgClaw/claw/claw/skills/skill_staging/skills/tq-lineloss-report/scripts/collect_lineloss.js"`

Expected: no syntax errors. (Note: the file uses `return` at top level inside a wrapped IIFE when injected into the browser, so Node syntax check may warn — the important thing is no parse errors.)

Alternatively, check the test file still works:

Run: `node "D:/data/ideaSpace/rust/sgClaw/claw/claw/skills/skill_staging/skills/tq-lineloss-report/scripts/collect_lineloss.test.js"`

Expected: tests pass (or at least no JS parse errors).

- [ ] **Step 7: Commit**

```bash
git add "D:/data/ideaSpace/rust/sgClaw/claw/claw/skills/skill_staging/skills/tq-lineloss-report/scripts/collect_lineloss.js"
git commit -m "feat(lineloss): remove browser-side export, defer to Rust-side XLSX generation"
```

---

### Task 4: Full Build Verification

**Files:** None (verification only)

- [ ] **Step 1: Run full cargo build**

Run: `cargo build`

Expected: successful compilation with no errors.

- [ ] **Step 2: Run all tests**

Run: `cargo test -- --nocapture`

Expected: all tests pass, including:
- `lineloss_xlsx_export_test::export_month_lineloss_produces_valid_xlsx`
- `lineloss_xlsx_export_test::export_empty_rows_returns_error`
- `lineloss_xlsx_export::tests::column_letter_maps_indices_correctly`
- All existing `deterministic_submit_test` tests

- [ ] **Step 3: Commit (if any fixups needed)**

Only if compilation or test fixes were required in this step.