[#Reports]
== Reports
include::../variables.adoc[]

QQQ can generate reports based on {link-tables} defined within a QQQ Instance.
Users can run reports, providing input values.
Alternatively, application code can run reports as needed, supplying input values.

=== QReportMetaData
Reports are defined in a QQQ Instance with a `*QReportMetaData*` object.
Reports are defined in terms of their sources of data (`QReportDataSource`), and their view(s) of that data (`QReportView`).

*QReportMetaData Properties:*

* `name` - *String, Required* - Unique name for the report within the QQQ Instance.
* `label` - *String* - User-facing label for the report, presented in User Interfaces.
Inferred from `name` if not set.
* `processName` - *String* - Name of a {link-process} used to run the report in a User Interface.
* `inputFields` - *List of {link-field}* - Optional list of fields used as input to the report.
** The values in these fields can be used via the syntax `${input.NAME}`, where `NAME` is the `name` attribute of the `inputField`.
** For example:

[source,java]
----
// given this inputField:
new QFieldMetaData("storeId", QFieldType.INTEGER)

// its run-time value can be accessed, e.g., in a query filter under a data source:
new QFilterCriteria("storeId", QCriteriaOperator.EQUALS, List.of("${input.storeId}"))

// or in a report view's title or field formulas:
.withTitleFields(List.of("${input.storeId}"))
new QReportField().withName("storeId").withFormula("${input.storeId}")
----

* `dataSources` - *List of QReportDataSource, Required* - Definitions of the sources of data for the report.
At least one is required.

==== QReportDataSource
Data sources for QQQ Reports can either reference {link-tables} within the QQQ Instance, or they can provide custom code in the form of a `CodeReference` to a  `Supplier`, for use cases such as a static data tab in an Excel report.

*QReportDataSource Properties:*

* `name` - *String, Required* - Unique name for the data source within its containing Report.
* `sourceTable` - *String, Conditional* - Reference to a {link-table} in the QQQ Instance, which the data source queries data from.
* `queryFilter` - *QQueryFilter* - If a `sourceTable` is defined, then the filter specified here is used to filter and sort the records queried from that table when generating the report.
* `staticDataSupplier` - *QCodeReference, Conditional* - Reference to custom code which can be used to supply the data for the data source, as an alternative to querying a `sourceTable`.
** Must be a `JAVA` code type
** Must be a `REPORT_STATIC_DATA_SUPPLIER` code usage.
** The referenced class must implement the interface: `Supplier<List<List<Serializable>>>`.

==== QReportView
Report Views control how the source data for a report is organized and presented to the user in the output report file.
If a DataSource describes the rows for a report (e.g., what table provides what records), then a View may be thought of as describing the columns in the report.
A single report can have multiple views, specifically, for the use-case where an Excel file is being generated, in which case each View creates a tab or sheet within the `xlsx` file.

*QReportView Properties:*

* `name` - *String, Required* - Unique name for the view within its containing Report.
* `label` - *String* - Used as a sheet (tab) label in Excel formatted reports.
* `type` - *enum of TABLE, SUMMARY, PIVOT. Required* - Defines the type of view being defined.
** *TABLE* views are a simple listing of the records from the data source.
** *SUMMARY* views are essentially pre-computed Pivot Tables.
That is to say, the aggregation done by a Pivot Table in a spreadsheet file is done by QQQ while generating the report.
In this way, a non-spreadsheet report (e.g., PDF or CSV) can have summarized data, as though it were a Pivot Table in a live spreadsheet.
** *PIVOT* views produce actual Pivot Tables, and are only supported in Excel files _(and are not supported at the time of this writing)_.
* `dataSourceName` - *String, Required* - Reference to a DataSource within the report, that is used to provide the rows for the view.
* `varianceDataSourceName` - *String* - Optional reference to a second DataSource within the report, that is used in `*SUMMARY*` type views for computing variances.
** For example, given a Data Source with a filter that selects all sales records for a given year, a Variance Data Source may have a filter that selects the previous year, for doing comparissons.
* `pivotFields` - *List of String, Conditional* - For *SUMMARY* or *PIVOT* type views, specify the field(s) used as pivot rows.
** For example, in a summary view of orders, you may "pivot" on the *customerId* field, to produce one row per-customer, with aggregate data for that customer.
* `titleFormat` - *String* - Java Format String, used with `titleFields` (if given), to produce a title row, e.g., first row in the view (before any rows from the data source).
* `titleFields` - *List of String, Conditional* - Used with `titleFormat`, to provide values for any format specifiers in the format string.
Syntax to reference a field (e.g., from a report input field) is: `${input.NAME}`, where `NAME` is the `name` attribute of the inputField.
** Example of using `titleFormat` and `titleFields`:

[source,java]
----
// given these inputFields:
new QFieldMetaData("startDate", QFieldType.DATE)
new QFieldMetaData("endDate", QFieldType.DATE)

// a view can have a title row like this:
.withTitleFormat("Weekly Sales Report - %s - %s")
.withTitleFields(List.of("${input.startDate}", "${input.endDate}"))
----

* `includeHeaderRow` - *boolean, default true* - Indication that first row of the view should be the column labels.
** If true, then header row is put in the view.
** If false, then no header row is put in the view.
* `includeTotalRow` - *boolean, default false* - Indication that a totals row should be added to the view.
All numeric columns are summed to produce values in the totals row.
** If true, then totals row is put in the view.
** If false, then no totals row is put in the view.
* `includePivotSubTotals` - *boolean, default false* - For a *SUMMARY* or *PIVOT* type view, if there are more than 1 *pivotFields* being used, this field is an indication that each higher-level pivot should include sub-totals.
** #TODO - provide example#
* `columns` - *List of QReportField, required* - Definition of the columns to appear in the view.  See section on QReportField for details.
* `orderByFields` - *List of QFilterOrderBy, optional* - For a *SUMMARY* or *PIVOT* type view, how to sort the rows.
* `recordTransformStep` - *QCodeReference, subclass of `AbstractTransformStep`* - Custom code reference that can be used to transform records after they are queried from the data source, and before they are placed into the view.
Can be used to transform or customize values, or to look up additional values to add to the report.
** #TODO - provide example#
* `viewCustomizer` - *QCodeReference, implementation of interface `Function<QReportView, QReportView>`* - Custom code reference that can be used to customize the report view, at runtime.
Can be used, for example, to dynamically define the report's *columns*.
** #TODO - provide example#

===== QReportField
Report Fields define the fields (AKA columns) of data that appear in a report view.
These fields can either be direct references to fields from the report's data sources, or values computed using formula defined in the QReportField.

*QReportField Properties:*

* `name` - *String, required* - Unique identifier for the field within its ReportView.
In general, will be a reference to a field from the ReportView's DataSource *unless a *formula* is given (for *SUMMARY* type views), the field is marked as *isVirtual*, or the field is marked as *showPossibleValueLabel*).
* `label` - *String* - Optional text label to identify the field, for example, in a header row.
If not given, may be derived from field, where possible.
* `type` - *QFieldType*
* `formula` - *String, conditional* - Required for *SUMMARY* type views.
Defines the formula to be used for computing the value in this field.
** For example:

[source,java]
----
.withName("reportEndDate").withFormula("${input.endDate}")

.withName("count").withFormula("${pivot.count.id}")

.withName("percentOfTotal").withFormula("=DIVIDE(${pivot.count.id},${total.count.id})")

.withName("sumCost").withFormula("${pivot.sum.cost}")

.withName("sumCharge").withFormula("${pivot.sum.charge}")

.withName("profit").withFormula("=MINUS(${pivot.sum.charge},${pivot.sum.cost})")

.withName("totalCost").withFormula("=DIVIDE_SCALE(${pivot.sum.cost},${pivot.count.id},2)")

.withName("revenuePer").withFormula("=DIVIDE_SCALE(${pivot.sum.charge},${pivot.count.id},2)")

.withName("marginPer").withFormula("=MINUS(DIVIDE_SCALE(${pivot.sum.charge},${pivot.count.id},2),DIVIDE_SCALE(${pivot.sum.cost},${pivot.count.id},2))")

.withName("thisWeekMargin").withFormula("=SCALE(DIVIDE(${thisRow.profit},${pivot.sum.charge}),2)")

.withName("previousWeekProfit").withFormula("=MINUS(${variancePivot.sum.charge},${variancePivot.sum.cost})")

.withName("previousWeekMargin").withFormula("=SCALE(DIVIDE(${thisRow.previousWeekProfit},${variancePivot.sum.charge}),2)")

.withName("marginThisVsPrevious").withFormula("=SCALE(MINUS(${thisRow.margin},${thisRow.marginPrevious}),3)")

.withName("exception").withFormula("""
   =IF(LT(${thisRow.margin},0),Negative Margin,IF(LT(${thisRow.marginThisVsPrevious},0),Margin Decreased,""))""")
----

* `displayFormat` *String*
* `isVirtual` *Boolean, default false* - (needs reviewed - may only be required for report views using a data source with a *staticDataSupplier*)
* `showPossibleValueLabel` *Boolean, default false* - To show a translated value for a Possible Value field (e.g., a name or other value meaningful to a user, instead of a foreign key).
* `sourceFieldName` *String* - Used for the scenario where a possibleValue field is included in a report both as the foreign key (raw, id value), and the translated "label" value.
In that case, the field marked with *showPossibleValueLabel* = true should be given a different name, and should use *sourceFieldName* to indicate the field that has the id value.
** For example:

[source,java]
----
// this field would have the "raw" warehouseId values
// e.g., integers - foreign keys to a warehouse table.  Generally useful for machines to know.
new QReportField("warehouseId")
   .withLabel("Warehouse Id"),

// this field would have the translated values from the warehouse PossibleValueSource
// for example, maybe the name field from the warehouse table.  A string, useful for humans to read.
new QReportField("warehouseName")
   .withSourceFieldName("warehouseId")
   .withShowPossibleValueLabel(true)
   .withLabel("Warehouse Name"),
----

