goose 0.19.1

use super::{
    delta::*, iterations_per_user, per_second_calculations, prepare_status_codes, CoMetricsSummary,
    GooseMetrics, GooseRequestMetricAggregate, GooseRequestMetricTimingData, Millis, MillisFloat,
    NullableFloat,
};

use crate::{
    report::{
        get_response_metric, CORequestMetric, ErrorMetric, RequestMetric, ResponseMetric,
        ScenarioMetric, StatusCodeMetric, TransactionErrorMetric, TransactionMetric,
    },
    util, GooseError,
};
use itertools::Itertools;
use serde::{Deserialize, Deserializer};
use std::borrow::Cow;
use std::collections::HashMap;
use std::fs::File;
use std::hash::Hash;
use std::io::{BufReader, Read};
use std::path::{Path, PathBuf};

/// Custom deserializer for f64 values that converts JSON null to f64::NAN
fn deserialize_nullable_f64<'de, D>(deserializer: D) -> Result<f64, D::Error>
where
    D: Deserializer<'de>,
{
    let opt: Option<f64> = Option::deserialize(deserializer)?;
    Ok(opt.unwrap_or(f64::NAN))
}

/// Write request rows without their per status code breakdown rows, which are
/// rebuilt from the request's status codes whenever a report is rendered.
fn serialize_without_breakdowns<S>(rows: &[RequestMetric], serializer: S) -> Result<S::Ok, S::Error>
where
    S: serde::Serializer,
{
    serializer.collect_seq(rows.iter().filter(|row| !row.is_breakdown))
}

#[derive(Debug, Clone, serde::Serialize, serde::Deserialize)]
pub(crate) struct ReportData<'m> {
    pub raw_metrics: Cow<'m, GooseMetrics>,

    /// Each request's row, followed by its per status code breakdown rows,
    /// then the Aggregated row. The JSON report holds no breakdown rows.
    #[serde(serialize_with = "serialize_without_breakdowns")]
    pub raw_request_metrics: Vec<RequestMetric>,
    pub raw_response_metrics: Vec<ResponseMetric>,

    pub co_request_metrics: Option<Vec<CORequestMetric>>,
    pub co_response_metrics: Option<Vec<ResponseMetric>>,

    pub scenario_metrics: Option<Vec<ScenarioMetric>>,
    pub transaction_metrics: Option<Vec<TransactionMetric>>,

    pub status_code_metrics: Option<Vec<StatusCodeMetric>>,

    pub errors: Option<Vec<ErrorMetric>>,

    /// The errors transactions returned; left out of the JSON report when
    /// there are none, as a report from before Goose recorded them has none.
    #[serde(default, skip_serializing_if = "Option::is_none")]
    pub transaction_errors: Option<Vec<TransactionErrorMetric>>,

    pub coordinated_omission_metrics: Option<CoMetricsSummary>,
}

pub struct ReportOptions {
    pub no_transaction_metrics: bool,
    pub no_scenario_metrics: bool,
    pub no_status_codes: bool,
}

pub fn prepare_data_with_baseline<'a>(
    options: ReportOptions,
    metrics: &'a GooseMetrics,
    baseline: Option<&ReportData>,
) -> ReportData<'a> {
    let prepare = Prepare::new(options, metrics);
    let mut result = prepare.build();
    if let Some(baseline) = baseline {
        apply_baseline_deltas(&mut result, baseline);
    }
    result
}

/// Every request's measured times, requests and failures added together, as the
/// report's Aggregated row shows them and thresholds judge them.
#[derive(Default)]
pub(crate) struct RequestTotals {
    /// Every request's measured times together. Its count can be lower than
    /// `requests`: with coordinated omission mitigation, those include the
    /// synthetic requests, which have no measured time.
    pub(crate) times: GooseRequestMetricTimingData,
    /// Every request counted, successful or failed.
    pub(crate) requests: usize,
    /// Every failed request.
    pub(crate) failures: usize,
}

impl RequestTotals {
    /// Add one request's figures.
    pub(crate) fn add(&mut self, request: &GooseRequestMetricAggregate) {
        self.requests += request.success_count + request.fail_count;
        self.failures += request.fail_count;
        self.times.merge(&request.raw_data);
    }

    /// Every one of `requests` added together.
    pub(crate) fn of<'a>(
        requests: impl IntoIterator<Item = &'a GooseRequestMetricAggregate>,
    ) -> Self {
        let mut totals = RequestTotals::default();
        for request in requests {
            totals.add(request);
        }
        totals
    }
}

struct RawIntermediate {
    /// Every request's measured times together.
    raw_aggregate: GooseRequestMetricTimingData,
}

struct Prepare<'m> {
    options: ReportOptions,
    metrics: &'m GooseMetrics,
    co_data: bool,
}

impl<'m> Prepare<'m> {
    fn new(options: ReportOptions, metrics: &'m GooseMetrics) -> Self {
        Self {
            options,
            metrics,
            co_data: false,
        }
    }

    fn build(mut self) -> ReportData<'m> {
        // Determine whether or not to include Coordinated Omission data.
        self.co_data = self
            .metrics
            .requests
            .values()
            .any(|request| request.coordinated_omission_data.is_some());

        let (raw_request_metrics, raw_response_metrics, intermediate) = self.build_raw();
        let (co_request_metrics, co_response_metrics) = self.build_co(&intermediate);

        ReportData {
            raw_metrics: Cow::Borrowed(self.metrics),
            raw_request_metrics,
            raw_response_metrics,
            co_request_metrics,
            co_response_metrics,
            scenario_metrics: self.build_scenario(),
            transaction_metrics: self.build_transaction(),
            status_code_metrics: self.build_status_code(),
            errors: self.build_errors(),
            transaction_errors: self.build_transaction_errors(),
            coordinated_omission_metrics: self
                .metrics
                .coordinated_omission_metrics
                .as_ref()
                .map(|co| co.get_summary()),
        }
    }

    fn build_raw(&self) -> (Vec<RequestMetric>, Vec<ResponseMetric>, RawIntermediate) {
        // Prepare requests and responses variables.
        let mut raw_request_metrics = vec![];
        let mut raw_response_metrics = vec![];
        let mut totals = RequestTotals::default();

        for (request_key, request) in self.metrics.requests.iter().sorted() {
            let method = request.method_label();
            // The request_key is "{method} {name}", so by stripping the "{method} "
            // prefix we get the name.
            let name = request_key
                .strip_prefix(&format!("{} ", method))
                .unwrap()
                .to_string();
            let total_request_count = request.success_count + request.fail_count;
            let (requests_per_second, failures_per_second) = per_second_calculations(
                self.metrics.duration,
                total_request_count,
                request.fail_count,
            );
            // Prepare per-request metrics.
            raw_request_metrics.push(RequestMetric {
                method: method.to_string(),
                name: name.to_string(),
                number_of_requests: total_request_count.into(),
                number_of_failures: request.fail_count.into(),
                response_time_average: request.raw_data.average_ms_or_zero().into(),
                response_time_minimum: Millis(request.raw_data.minimum_time_us).into(),
                response_time_maximum: Millis(request.raw_data.maximum_time_us).into(),
                requests_per_second: requests_per_second.into(),
                failures_per_second: failures_per_second.into(),
                is_breakdown: false,
            });

            // Add per-status-code breakdown rows when multiple status codes exist.
            if let Some(breakdowns) = request.status_code_breakdowns() {
                for b in breakdowns {
                    raw_request_metrics.push(RequestMetric {
                        method: format!("{} ({:.1}%)", b.status_code, b.percentage),
                        name: String::new(),
                        number_of_requests: b.count.into(),
                        number_of_failures: 0usize.into(),
                        response_time_average: b.average.into(),
                        response_time_minimum: Millis(b.min_time_us).into(),
                        response_time_maximum: Millis(b.max_time_us).into(),
                        requests_per_second: 0.0f32.into(),
                        failures_per_second: 0.0f32.into(),
                        is_breakdown: true,
                    });
                }
            }

            // Prepare per-response metrics.
            raw_response_metrics.push(get_response_metric(method, &name, &request.raw_data));

            // Collect aggregated request and response metrics.
            totals.add(request);
        }
        let RequestTotals {
            times: raw_aggregate,
            requests: raw_aggregate_total_count,
            failures: raw_aggregate_fail_count,
        } = totals;

        // Prepare aggregate per-request metrics.
        let (raw_aggregate_requests_per_second, raw_aggregate_failures_per_second) =
            per_second_calculations(
                self.metrics.duration,
                raw_aggregate_total_count,
                raw_aggregate_fail_count,
            );
        raw_request_metrics.push(RequestMetric {
            method: "".to_string(),
            name: "Aggregated".to_string(),
            number_of_requests: raw_aggregate_total_count.into(),
            number_of_failures: raw_aggregate_fail_count.into(),
            response_time_average: raw_aggregate.average_ms_or_zero().into(),
            response_time_minimum: Millis(raw_aggregate.minimum_time_us).into(),
            response_time_maximum: Millis(raw_aggregate.maximum_time_us).into(),
            requests_per_second: raw_aggregate_requests_per_second.into(),
            failures_per_second: raw_aggregate_failures_per_second.into(),
            is_breakdown: false,
        });

        // Prepare aggregate per-response metrics.
        raw_response_metrics.push(get_response_metric("", "Aggregated", &raw_aggregate));

        (
            raw_request_metrics,
            raw_response_metrics,
            RawIntermediate { raw_aggregate },
        )
    }

    fn build_co(
        &self,
        intermediate: &RawIntermediate,
    ) -> (Option<Vec<CORequestMetric>>, Option<Vec<ResponseMetric>>) {
        if !self.co_data {
            return (None, None);
        }

        let mut co_request_metrics = vec![];
        let mut co_response_metrics = vec![];
        // Every request's adjusted times together: its measured times plus
        // the synthetic ones, or only its measured times when mitigation
        // added none to it.
        let mut co_aggregate = GooseRequestMetricTimingData::new(None);

        for (request_key, request) in self.metrics.requests.iter().sorted() {
            co_aggregate.merge(
                request
                    .coordinated_omission_data
                    .as_ref()
                    .unwrap_or(&request.raw_data),
            );
            if let Some(coordinated_omission_data) = request.coordinated_omission_data.as_ref() {
                let method = request.method_label();
                // The request_key is "{method} {name}", so by stripping the "{method} "
                // prefix we get the name.
                let name = request_key
                    .strip_prefix(&format!("{} ", method))
                    .unwrap()
                    .to_string();
                let raw_average = request.raw_data.average_ms_or_zero();
                let co_average = coordinated_omission_data.average_ms_or_zero();
                // Prepare per-request metrics.
                co_request_metrics.push(CORequestMetric {
                    method: method.to_string(),
                    name: name.to_string(),
                    response_time_average: co_average.into(),
                    response_time_standard_deviation: util::standard_deviation(
                        raw_average as f32,
                        co_average as f32,
                    )
                    .into(),
                    response_time_maximum: Millis(coordinated_omission_data.maximum_time_us).into(),
                });

                // Prepare per-response metrics.
                co_response_metrics.push(get_response_metric(
                    method,
                    &name,
                    coordinated_omission_data,
                ));
            }
        }
        let co_average = co_aggregate.average_ms_or_zero();
        let raw_average = intermediate.raw_aggregate.average_ms_or_zero();
        co_request_metrics.push(CORequestMetric {
            method: "".to_string(),
            name: "Aggregated".to_string(),
            response_time_average: co_average.into(),
            response_time_standard_deviation: util::standard_deviation(
                raw_average as f32,
                co_average as f32,
            )
            .into(),
            response_time_maximum: Millis(co_aggregate.maximum_time_us).into(),
        });

        // Prepare aggregate per-response metrics.
        co_response_metrics.push(get_response_metric("", "Aggregated", &co_aggregate));

        (Some(co_request_metrics), Some(co_response_metrics))
    }

    fn build_transaction(&self) -> Option<Vec<TransactionMetric>> {
        if self.options.no_transaction_metrics {
            return None;
        }

        let mut transaction_metrics = Vec::new();
        let mut aggregate_total_count = 0;
        let mut aggregate_fail_count = 0;
        // Every transaction's run times together.
        let mut aggregate_times = GooseRequestMetricTimingData::default();
        for (scenario_counter, scenario) in self.metrics.transactions.iter().enumerate() {
            for (transaction_counter, transaction) in scenario.iter().enumerate() {
                if transaction_counter == 0 {
                    // Only the scenario_name is used for scenarios.
                    transaction_metrics.push(TransactionMetric {
                        is_scenario: true,
                        transaction: "".to_string(),
                        name: transaction.scenario_name.to_string(),
                        number_of_requests: 0usize.into(),
                        number_of_failures: 0usize.into(),
                        response_time_average: None,
                        response_time_minimum: 0usize.into(),
                        response_time_maximum: 0usize.into(),
                        requests_per_second: None,
                        failures_per_second: None,
                    });
                }
                let total_run_count = transaction.success_count + transaction.fail_count;
                let (requests_per_second, failures_per_second) = per_second_calculations(
                    self.metrics.duration,
                    total_run_count,
                    transaction.fail_count,
                );
                let times = &transaction.run_times;
                transaction_metrics.push(TransactionMetric {
                    is_scenario: false,
                    transaction: format!("{scenario_counter}.{transaction_counter}"),
                    name: transaction
                        .transaction_name
                        .name_for_transaction()
                        .to_string(),
                    number_of_requests: total_run_count.into(),
                    number_of_failures: transaction.fail_count.into(),
                    response_time_average: Some(times.average_ms_or_zero().into()),
                    response_time_minimum: Millis(times.minimum_time_us).into(),
                    response_time_maximum: Millis(times.maximum_time_us).into(),
                    requests_per_second: Some(requests_per_second.into()),
                    failures_per_second: Some(failures_per_second.into()),
                });

                aggregate_total_count += total_run_count;
                aggregate_fail_count += transaction.fail_count;
                aggregate_times.merge(times);
            }
        }

        let (aggregate_requests_per_second, aggregate_failures_per_second) =
            per_second_calculations(
                self.metrics.duration,
                aggregate_total_count,
                aggregate_fail_count,
            );
        transaction_metrics.push(TransactionMetric {
            is_scenario: false,
            transaction: "".to_string(),
            name: "Aggregated".to_string(),
            number_of_requests: aggregate_total_count.into(),
            number_of_failures: aggregate_fail_count.into(),
            response_time_average: Some(aggregate_times.average_ms_or_zero().into()),
            response_time_minimum: Millis(aggregate_times.minimum_time_us).into(),
            response_time_maximum: Millis(aggregate_times.maximum_time_us).into(),
            requests_per_second: Some(aggregate_requests_per_second.into()),
            failures_per_second: Some(aggregate_failures_per_second.into()),
        });

        Some(transaction_metrics)
    }

    fn build_scenario(&self) -> Option<Vec<ScenarioMetric>> {
        if self.options.no_scenario_metrics {
            return None;
        }

        let mut scenario_metrics = Vec::new();
        let mut aggregate_users = 0;
        // Every scenario's run times together.
        let mut aggregate_times = GooseRequestMetricTimingData::default();
        for scenario in &self.metrics.scenarios {
            let times = &scenario.run_times;
            let (count_per_second, _failures_per_second) =
                per_second_calculations(self.metrics.duration, times.counter, 0);
            let iterations = iterations_per_user(times.counter, scenario.users.len());
            scenario_metrics.push(ScenarioMetric {
                name: scenario.name.to_string(),
                users: scenario.users.len().into(),
                count: times.counter.into(),
                response_time_average: times.average_ms_or_zero().into(),
                response_time_minimum: Millis(times.minimum_time_us).into(),
                response_time_maximum: Millis(times.maximum_time_us).into(),
                count_per_second: count_per_second.into(),
                iterations: iterations.into(),
            });

            aggregate_users += scenario.users.len();
            aggregate_times.merge(times);
        }

        let (aggregate_count_per_second, _aggregate_failures_per_second) =
            per_second_calculations(self.metrics.duration, aggregate_times.counter, 0);
        scenario_metrics.push(ScenarioMetric {
            name: "Aggregated".to_string(),
            users: aggregate_users.into(),
            count: aggregate_times.counter.into(),
            response_time_average: aggregate_times.average_ms_or_zero().into(),
            response_time_minimum: Millis(aggregate_times.minimum_time_us).into(),
            response_time_maximum: Millis(aggregate_times.maximum_time_us).into(),
            count_per_second: aggregate_count_per_second.into(),
            iterations: iterations_per_user(aggregate_times.counter, aggregate_users).into(),
        });

        Some(scenario_metrics)
    }

    fn build_status_code(&self) -> Option<Vec<StatusCodeMetric>> {
        if self.options.no_status_codes {
            return None;
        }

        let mut status_code_metrics = Vec::new();
        let mut aggregated_status_code_counts: HashMap<u16, usize> = HashMap::new();
        for (request_key, request) in self.metrics.requests.iter().sorted() {
            let method = request.method_label();
            // The request_key is "{method} {name}", so by stripping the "{method} "
            // prefix we get the name.
            let name = request_key
                .strip_prefix(&format!("{} ", method))
                .unwrap()
                .to_string();

            // Build a list of status codes, and update the aggregate record.
            let codes = prepare_status_codes(
                &request.status_code_counts,
                &mut Some(&mut aggregated_status_code_counts),
            );

            // Add a row of data for the status code table.
            status_code_metrics.push(StatusCodeMetric {
                method: method.to_string(),
                name,
                status_codes: codes,
            });
        }

        // Build a list of aggregate status codes.
        let aggregated_codes = prepare_status_codes(&aggregated_status_code_counts, &mut None);

        // Add a final row of aggregate data for the status code table.
        status_code_metrics.push(StatusCodeMetric {
            method: "".to_string(),
            name: "Aggregated".to_string(),
            status_codes: aggregated_codes,
        });

        Some(status_code_metrics)
    }

    fn build_errors(&self) -> Option<Vec<ErrorMetric>> {
        if self.metrics.errors.is_empty() {
            return None;
        }

        let errors: Vec<ErrorMetric> = self
            .metrics
            .errors
            .values()
            .map(|error| ErrorMetric {
                method: error.method_label().to_string(),
                name: error.name.clone(),
                error: error.error.clone(),
                occurrences: error.occurrences.into(),
            })
            .collect();

        Some(errors)
    }

    fn build_transaction_errors(&self) -> Option<Vec<TransactionErrorMetric>> {
        if self.metrics.transaction_errors.is_empty() {
            return None;
        }

        // Most frequent first, as the console and the dashboard list them.
        let mut errors: Vec<_> = self.metrics.transaction_errors.values().collect();
        errors.sort_by(|a, b| {
            b.occurrences
                .cmp(&a.occurrences)
                .then_with(|| a.scenario_index.cmp(&b.scenario_index))
                .then_with(|| a.transaction_index.cmp(&b.transaction_index))
                .then_with(|| a.error.cmp(&b.error))
        });
        Some(
            errors
                .into_iter()
                .map(|error| TransactionErrorMetric {
                    transaction: error.transaction_number(),
                    scenario: error.scenario_name.clone(),
                    name: error.transaction_name.clone(),
                    error: error.error.clone(),
                    occurrences: error.occurrences.into(),
                })
                .collect(),
        )
    }
}

/// Apply baseline deltas to the current report data
pub(crate) fn apply_baseline_deltas(current: &mut ReportData, baseline: &ReportData) {
    // Apply deltas to raw request metrics
    correlate_deltas(
        &mut current.raw_request_metrics,
        &baseline.raw_request_metrics,
        |r| (r.method.clone(), r.name.clone()),
    );

    // Apply deltas to raw response metrics
    correlate_deltas(
        &mut current.raw_response_metrics,
        &baseline.raw_response_metrics,
        |r| (r.method.clone(), r.name.clone()),
    );

    // Apply deltas to CO request metrics if present
    if let (Some(current_co), Some(baseline_co)) = (
        &mut current.co_request_metrics,
        &baseline.co_request_metrics,
    ) {
        correlate_deltas(current_co, baseline_co, |r| {
            (r.method.clone(), r.name.clone())
        });
    }

    // Apply deltas to CO response metrics if present
    if let (Some(current_co), Some(baseline_co)) = (
        &mut current.co_response_metrics,
        &baseline.co_response_metrics,
    ) {
        correlate_deltas(current_co, baseline_co, |r| {
            (r.method.clone(), r.name.clone())
        });
    }

    // Apply deltas to transaction metrics if present
    if let (Some(current_transactions), Some(baseline_transactions)) = (
        &mut current.transaction_metrics,
        &baseline.transaction_metrics,
    ) {
        correlate_deltas(current_transactions, baseline_transactions, |t| {
            (t.transaction.clone(), t.name.clone())
        });
    }

    // Apply deltas to scenario metrics if present
    if let (Some(current_scenarios), Some(baseline_scenarios)) =
        (&mut current.scenario_metrics, &baseline.scenario_metrics)
    {
        correlate_deltas(current_scenarios, baseline_scenarios, |s| s.name.clone());
    }

    // Apply deltas to error metrics if present
    if let (Some(current_errors), Some(baseline_errors)) = (&mut current.errors, &baseline.errors) {
        correlate_deltas(current_errors, baseline_errors, |e| {
            (e.method.clone(), e.name.clone(), e.error.clone())
        });
    }

    // Apply deltas to transaction error metrics if present
    if let (Some(current_errors), Some(baseline_errors)) = (
        &mut current.transaction_errors,
        &baseline.transaction_errors,
    ) {
        correlate_deltas(current_errors, baseline_errors, |e| {
            (
                e.scenario.clone(),
                e.transaction.clone(),
                e.name.clone(),
                e.error.clone(),
            )
        });
    }
}

/// The JSON report at `path`, or in the folder `path` names: its
/// `report.json`, else its `report.json.gz`.
pub(crate) fn json_report_path(path: &Path) -> PathBuf {
    if !path.is_dir() {
        return path.to_path_buf();
    }
    let json = path.join(crate::runs::REPORT_JSON);
    if json.is_file() {
        json
    } else {
        path.join(format!("{}.gz", crate::runs::REPORT_JSON))
    }
}

/// Read a report, gunzipping one whose name ends in `.gz`.
pub(crate) fn open_report(path: &Path) -> std::io::Result<Box<dyn Read>> {
    let file = BufReader::new(File::open(path)?);
    if crate::runs::without_gz(&path.to_string_lossy()).1 {
        Ok(Box::new(flate2::read::MultiGzDecoder::new(file)))
    } else {
        Ok(Box::new(file))
    }
}

/// The text of a report, gunzipped when its name ends in `.gz`.
pub(crate) fn read_report_text(path: &Path) -> std::io::Result<String> {
    let mut text = String::new();
    open_report(path)?.read_to_string(&mut text)?;
    Ok(text)
}

/// Load baseline data from a JSON report, plain or gzipped, or from the
/// `report.json`, else `report.json.gz`, in a folder when `path` is a folder.
pub fn load_baseline_file<P: AsRef<Path>>(path: P) -> Result<ReportData<'static>, GooseError> {
    let path_str = path.as_ref().to_string_lossy();
    let file_path = json_report_path(path.as_ref());

    // Open and read the baseline file
    let file = open_report(&file_path).map_err(|err| GooseError::InvalidOption {
        option: "--baseline-file".to_string(),
        value: path_str.to_string(),
        detail: format!("Failed to open baseline file: {err}"),
    })?;

    let mut baseline = read_report(file).map_err(|err| GooseError::InvalidOption {
        option: "--baseline-file".to_string(),
        value: path_str.to_string(),
        detail: format!("Failed to parse baseline file as JSON: {err}"),
    })?;

    // Validate the loaded baseline data
    validate_baseline_data(&baseline, &path_str)?;

    // Convert borrowed data to owned for static lifetime
    baseline.raw_metrics = Cow::Owned(baseline.raw_metrics.into_owned());

    Ok(baseline)
}

/// A JSON report read back: its tables, the record of its run, and its graph
/// data when it holds any.
pub(crate) struct LoadedReport {
    pub data: ReportData<'static>,
    pub record: crate::runs::RunRecord,
    pub graphs: Option<(crate::graph::GraphData, Option<serde_json::Value>)>,
}

impl LoadedReport {
    /// Read the JSON report at `path`. An error is one line for the person who
    /// asked.
    pub(crate) fn read(path: &Path) -> Result<LoadedReport, String> {
        let text =
            read_report_text(path).map_err(|e| format!("Can't read {}: {e}", path.display()))?;
        Self::parse(&text)
            .map_err(|e| format!("{} is not a Goose JSON report: {e}", path.display()))
    }

    /// A JSON report's text read back.
    pub(crate) fn parse(text: &str) -> Result<LoadedReport, serde_json::Error> {
        #[derive(Deserialize)]
        struct Graphs {
            graphs: Option<crate::graph::RecordedGraphs>,
        }
        let mut data = read_report(text.as_bytes())?;
        data.raw_metrics = Cow::Owned(data.raw_metrics.into_owned());
        restore_breakdown_rows(&mut data);
        Ok(LoadedReport {
            data,
            record: serde_json::from_str(text)?,
            graphs: serde_json::from_str::<Graphs>(text)?
                .graphs
                .map(crate::graph::RecordedGraphs::into_parts),
        })
    }

    /// The reports written from this one, by `configuration`'s options.
    pub(crate) fn source<'a>(
        &'a self,
        configuration: &'a crate::GooseConfiguration,
        empty: &'a crate::graph::GraphData,
    ) -> super::ReportSource<'a> {
        let (graph_data, heatmap) = match &self.graphs {
            Some((graph_data, heatmap)) => (graph_data, heatmap.as_ref()),
            None => (empty, None),
        };
        super::ReportSource {
            configuration,
            metrics: &self.data.raw_metrics,
            graph_data,
            graphs: self.graphs.is_some(),
            heatmap,
            loaded: Some(&self.data),
            record: &self.record,
            graph_data_in_json: self.graphs.is_some(),
        }
    }
}

/// Compare two runs: the run's JSON report with the baseline run's
/// deltas applied, rendered by the Markdown report writer. An error is one
/// line of plain text for the person who asked.
#[cfg(feature = "dashboard")]
pub(crate) fn compare_reports(
    run: &Path,
    run_id: &str,
    baseline: &Path,
    baseline_id: &str,
) -> Result<Vec<u8>, String> {
    let load = |path: &Path, id: &str| -> Result<ReportData<'static>, String> {
        let reader = open_report(path).map_err(|e| format!("Can't read run {id}: {e}"))?;
        let data =
            read_report(reader).map_err(|e| format!("Can't read the report of run {id}: {e}"))?;
        let requests = data
            .raw_request_metrics
            .iter()
            .filter(|r| !r.is_breakdown)
            .count();
        if requests == 0 {
            return Err(format!("Run {id} has no requests to compare."));
        }
        if requests != data.raw_response_metrics.len() {
            return Err(format!("The report of run {id} is inconsistent."));
        }
        Ok(data)
    };
    let mut current = load(run, run_id)?;
    let previous = load(baseline, baseline_id)?;
    apply_baseline_deltas(&mut current, &previous);
    let mut out = Vec::new();
    crate::report::write_markdown_report(&mut out, current, &[])
        .map_err(|e| format!("Can't compare run {run_id} with run {baseline_id}: {e}"))?;
    Ok(out)
}

/// A JSON report as a baseline. A report's JSON minimums, maximums and
/// percentiles hold whole milliseconds, so when the report has microsecond
/// buckets its rows are rebuilt from its raw timing data, as a live report's
/// are. A report without microsecond buckets keeps its rows.
fn read_report(mut reader: impl Read) -> Result<ReportData<'static>, serde_json::Error> {
    let mut text = String::new();
    reader
        .read_to_string(&mut text)
        .map_err(serde_json::Error::io)?;
    let mut report = serde_json::from_str::<BaselineReportData>(&text)?.into_report_data();
    if serde_json::from_str::<MicrosecondsProbe>(&text)?.has_microseconds() {
        // The rows are rebuilt as a live report's are, which takes each
        // request's name from its key, "{method} {name}".
        if let Some(key) = report
            .raw_metrics
            .requests
            .iter()
            .find_map(|(key, request)| {
                (!key.starts_with(&format!("{} ", request.method_label()))).then_some(key)
            })
        {
            return Err(serde::de::Error::custom(format!(
                "request {key:?} does not start with its method"
            )));
        }
        rebuild_timed_rows(&mut report);
    }
    Ok(report)
}

/// Whether a JSON report's requests, transactions or scenarios carry
/// `times_us`, as reports from Goose 0.19 on do.
#[derive(Deserialize)]
struct MicrosecondsProbe {
    raw_metrics: ProbeMetrics,
}

#[derive(Deserialize)]
struct ProbeMetrics {
    requests: HashMap<String, ProbeRequest>,
    #[serde(default)]
    transactions: Vec<Vec<ProbeTimingData>>,
    #[serde(default)]
    scenarios: Vec<ProbeTimingData>,
}

#[derive(Deserialize)]
struct ProbeRequest {
    raw_data: ProbeTimingData,
}

#[derive(Deserialize)]
struct ProbeTimingData {
    times_us: Option<serde::de::IgnoredAny>,
}

impl MicrosecondsProbe {
    fn has_microseconds(&self) -> bool {
        let metrics = &self.raw_metrics;
        metrics
            .requests
            .values()
            .any(|request| request.raw_data.times_us.is_some())
            || metrics
                .transactions
                .iter()
                .flatten()
                .any(|transaction| transaction.times_us.is_some())
            || metrics
                .scenarios
                .iter()
                .any(|scenario| scenario.times_us.is_some())
    }
}

/// Replace the request, coordinated omission, transaction and scenario rows
/// of `report` with the rows its raw timing data gives. Status code
/// breakdown rows, whose times the raw data does not keep, stay.
fn rebuild_timed_rows(report: &mut ReportData<'static>) {
    let ReportData {
        raw_request_metrics,
        raw_response_metrics,
        co_request_metrics,
        co_response_metrics,
        transaction_metrics,
        scenario_metrics,
        ..
    } = Prepare::new(
        ReportOptions {
            no_transaction_metrics: report.transaction_metrics.is_none(),
            no_scenario_metrics: report.scenario_metrics.is_none(),
            no_status_codes: true,
        },
        &report.raw_metrics,
    )
    .build();
    let request_key = |r: &RequestMetric| (r.method.clone(), r.name.clone());
    let response_key = |r: &ResponseMetric| (r.method.clone(), r.name.clone());
    replace_rows(
        &mut report.raw_request_metrics,
        raw_request_metrics,
        request_key,
    );
    replace_rows(
        &mut report.raw_response_metrics,
        raw_response_metrics,
        response_key,
    );
    if let (Some(stored), Some(rebuilt)) = (&mut report.co_request_metrics, co_request_metrics) {
        replace_rows(stored, rebuilt, |r| (r.method.clone(), r.name.clone()));
    }
    if let (Some(stored), Some(rebuilt)) = (&mut report.co_response_metrics, co_response_metrics) {
        replace_rows(stored, rebuilt, response_key);
    }
    if let (Some(stored), Some(rebuilt)) = (&mut report.transaction_metrics, transaction_metrics) {
        replace_rows(stored, rebuilt, |t| (t.transaction.clone(), t.name.clone()));
    }
    if let (Some(stored), Some(rebuilt)) = (&mut report.scenario_metrics, scenario_metrics) {
        replace_rows(stored, rebuilt, |s| s.name.clone());
    }
}

/// Put back the per status code breakdown rows a JSON report leaves out, each
/// after its request's row, as a live report has them.
fn restore_breakdown_rows(report: &mut ReportData<'static>) {
    let (rebuilt, _, _) = Prepare::new(
        ReportOptions {
            no_transaction_metrics: true,
            no_scenario_metrics: true,
            no_status_codes: true,
        },
        &report.raw_metrics,
    )
    .build_raw();
    // The breakdown rows that follow each request's row, by that row's key.
    let mut breakdowns: HashMap<(String, String), Vec<RequestMetric>> = HashMap::new();
    let mut parent = None;
    for row in rebuilt {
        if row.is_breakdown {
            if let Some(key) = &parent {
                breakdowns.entry(Clone::clone(key)).or_default().push(row);
            }
        } else {
            parent = Some((row.method, row.name));
        }
    }
    if breakdowns.is_empty() {
        return;
    }
    let stored = std::mem::take(&mut report.raw_request_metrics);
    for row in stored {
        let following = breakdowns.remove(&(row.method.clone(), row.name.clone()));
        report.raw_request_metrics.push(row);
        report
            .raw_request_metrics
            .extend(following.into_iter().flatten());
    }
}

/// Replace each row of `stored` with the row of `rebuilt` that has its key.
fn replace_rows<T, K: Eq + Hash>(stored: &mut [T], rebuilt: Vec<T>, key: impl Fn(&T) -> K) {
    let mut rebuilt: HashMap<K, T> = rebuilt.into_iter().map(|row| (key(&row), row)).collect();
    for row in stored {
        if let Some(new) = rebuilt.remove(&key(row)) {
            *row = new;
        }
    }
}

/// Intermediate structure for deserializing baseline data with plain values
/// that need to be converted to Value<T> enum format
#[derive(Debug, Deserialize)]
struct BaselineReportData {
    pub raw_metrics: BaselineGooseMetrics,
    pub raw_request_metrics: Vec<BaselineRequestMetric>,
    pub raw_response_metrics: Vec<BaselineResponseMetric>,
    pub co_request_metrics: Option<Vec<BaselineCORequestMetric>>,
    pub co_response_metrics: Option<Vec<BaselineResponseMetric>>,
    pub scenario_metrics: Option<Vec<BaselineScenarioMetric>>,
    pub transaction_metrics: Option<Vec<BaselineTransactionMetric>>,
    pub status_code_metrics: Option<Vec<StatusCodeMetric>>,
    pub errors: Option<Vec<BaselineErrorMetric>>,
    #[serde(default)]
    pub transaction_errors: Option<Vec<BaselineTransactionErrorMetric>>,
    pub coordinated_omission_metrics: Option<CoMetricsSummary>,
}

/// Baseline GooseMetrics structure that handles missing history field
#[derive(Debug, Deserialize)]
struct BaselineGooseMetrics {
    pub hash: u64,
    #[serde(default)]
    pub history: Vec<crate::test_plan::TestPlanHistory>,
    pub duration: usize,
    pub maximum_users: usize,
    pub total_users: usize,
    pub requests: super::GooseRequestMetrics,
    pub transactions: super::TransactionMetrics,
    #[serde(default)]
    pub scenarios: super::ScenarioMetrics,
    pub errors: super::GooseErrorMetrics,
    #[serde(default)]
    pub transaction_errors: super::GooseTransactionErrorMetrics,
    #[serde(default)]
    pub hosts: std::collections::HashSet<String>,
    pub coordinated_omission_metrics: Option<super::CoordinatedOmissionMetrics>,
    #[serde(default)]
    pub final_metrics: bool,
    #[serde(default)]
    pub display_status_codes: bool,
    #[serde(default)]
    pub display_metrics: bool,
    #[serde(default)]
    pub thresholds: Vec<crate::threshold::ThresholdResult>,
}

impl From<BaselineGooseMetrics> for GooseMetrics {
    fn from(baseline: BaselineGooseMetrics) -> Self {
        GooseMetrics {
            hash: baseline.hash,
            history: baseline.history,
            duration: baseline.duration,
            maximum_users: baseline.maximum_users,
            total_users: baseline.total_users,
            requests: baseline.requests,
            transactions: baseline.transactions,
            scenarios: baseline.scenarios,
            errors: baseline.errors,
            transaction_errors: baseline.transaction_errors,
            hosts: baseline.hosts,
            coordinated_omission_metrics: baseline.coordinated_omission_metrics,
            final_metrics: baseline.final_metrics,
            display_status_codes: baseline.display_status_codes,
            display_metrics: baseline.display_metrics,
            thresholds: baseline.thresholds,
            threshold_abort: None,
            rps_window: Default::default(),
        }
    }
}

impl BaselineReportData {
    fn into_report_data(self) -> ReportData<'static> {
        ReportData {
            raw_metrics: Cow::Owned(self.raw_metrics.into()),
            raw_request_metrics: self
                .raw_request_metrics
                .into_iter()
                .map(Into::into)
                .collect(),
            raw_response_metrics: self
                .raw_response_metrics
                .into_iter()
                .map(Into::into)
                .collect(),
            co_request_metrics: self
                .co_request_metrics
                .map(|metrics| metrics.into_iter().map(Into::into).collect()),
            co_response_metrics: self
                .co_response_metrics
                .map(|metrics| metrics.into_iter().map(Into::into).collect()),
            scenario_metrics: self
                .scenario_metrics
                .map(|metrics| metrics.into_iter().map(Into::into).collect()),
            transaction_metrics: self
                .transaction_metrics
                .map(|metrics| metrics.into_iter().map(Into::into).collect()),
            status_code_metrics: self.status_code_metrics,
            errors: self
                .errors
                .map(|errors| errors.into_iter().map(Into::into).collect()),
            transaction_errors: self
                .transaction_errors
                .map(|errors| errors.into_iter().map(Into::into).collect()),
            coordinated_omission_metrics: self.coordinated_omission_metrics,
        }
    }
}

/// Baseline request metric with plain values
#[derive(Debug, Deserialize)]
struct BaselineRequestMetric {
    pub method: String,
    pub name: String,
    pub number_of_requests: usize,
    pub number_of_failures: usize,
    #[serde(deserialize_with = "deserialize_nullable_f64")]
    pub response_time_average: f64,
    pub response_time_minimum: usize,
    pub response_time_maximum: usize,
    #[serde(deserialize_with = "deserialize_nullable_f64")]
    pub requests_per_second: f64,
    #[serde(deserialize_with = "deserialize_nullable_f64")]
    pub failures_per_second: f64,
    #[serde(default)]
    pub is_breakdown: bool,
}

impl From<BaselineRequestMetric> for RequestMetric {
    fn from(baseline: BaselineRequestMetric) -> Self {
        RequestMetric {
            method: baseline.method,
            name: baseline.name,
            number_of_requests: Value::Plain(baseline.number_of_requests),
            number_of_failures: Value::Plain(baseline.number_of_failures),
            response_time_average: Value::Plain(MillisFloat(baseline.response_time_average)),
            response_time_minimum: baseline.response_time_minimum.into(),
            response_time_maximum: baseline.response_time_maximum.into(),
            requests_per_second: Value::Plain(NullableFloat(baseline.requests_per_second)),
            failures_per_second: Value::Plain(NullableFloat(baseline.failures_per_second)),
            is_breakdown: baseline.is_breakdown,
        }
    }
}

/// Baseline response metric with plain values
#[derive(Debug, Deserialize)]
struct BaselineResponseMetric {
    pub method: String,
    pub name: String,
    pub percentile_50: usize,
    pub percentile_60: usize,
    pub percentile_70: usize,
    pub percentile_80: usize,
    pub percentile_90: usize,
    pub percentile_95: usize,
    pub percentile_99: usize,
    pub percentile_100: usize,
}

impl From<BaselineResponseMetric> for ResponseMetric {
    fn from(baseline: BaselineResponseMetric) -> Self {
        ResponseMetric {
            method: baseline.method,
            name: baseline.name,
            percentile_50: baseline.percentile_50.into(),
            percentile_60: baseline.percentile_60.into(),
            percentile_70: baseline.percentile_70.into(),
            percentile_80: baseline.percentile_80.into(),
            percentile_90: baseline.percentile_90.into(),
            percentile_95: baseline.percentile_95.into(),
            percentile_99: baseline.percentile_99.into(),
            percentile_100: baseline.percentile_100.into(),
        }
    }
}

/// Baseline coordinated omission request metric with plain values
#[derive(Debug, Deserialize)]
struct BaselineCORequestMetric {
    pub method: String,
    pub name: String,
    pub response_time_average: f64,
    pub response_time_standard_deviation: f64,
    pub response_time_maximum: usize,
}

impl From<BaselineCORequestMetric> for CORequestMetric {
    fn from(baseline: BaselineCORequestMetric) -> Self {
        CORequestMetric {
            method: baseline.method,
            name: baseline.name,
            response_time_average: Value::Plain(MillisFloat(baseline.response_time_average)),
            response_time_standard_deviation: Value::Plain(MillisFloat(
                baseline.response_time_standard_deviation,
            )),
            response_time_maximum: baseline.response_time_maximum.into(),
        }
    }
}

/// Baseline transaction metric with plain values
#[derive(Debug, Deserialize)]
struct BaselineTransactionMetric {
    pub is_scenario: bool,
    pub transaction: String,
    pub name: String,
    pub number_of_requests: usize,
    pub number_of_failures: usize,
    pub response_time_average: Option<f64>,
    pub response_time_minimum: usize,
    pub response_time_maximum: usize,
    pub requests_per_second: Option<f64>,
    pub failures_per_second: Option<f64>,
}

impl From<BaselineTransactionMetric> for TransactionMetric {
    fn from(baseline: BaselineTransactionMetric) -> Self {
        TransactionMetric {
            is_scenario: baseline.is_scenario,
            transaction: baseline.transaction,
            name: baseline.name,
            number_of_requests: Value::Plain(baseline.number_of_requests),
            number_of_failures: Value::Plain(baseline.number_of_failures),
            response_time_average: baseline
                .response_time_average
                .map(|v| Value::Plain(MillisFloat(v))),
            response_time_minimum: baseline.response_time_minimum.into(),
            response_time_maximum: baseline.response_time_maximum.into(),
            requests_per_second: baseline
                .requests_per_second
                .map(|v| Value::Plain(NullableFloat(v))),
            failures_per_second: baseline
                .failures_per_second
                .map(|v| Value::Plain(NullableFloat(v))),
        }
    }
}

/// Baseline scenario metric with plain values
#[derive(Debug, Deserialize)]
struct BaselineScenarioMetric {
    pub name: String,
    pub users: usize,
    pub count: usize,
    pub response_time_average: Option<f64>,
    pub response_time_minimum: usize,
    pub response_time_maximum: usize,
    pub count_per_second: f64,
    pub iterations: Option<f64>,
}

impl From<BaselineScenarioMetric> for ScenarioMetric {
    fn from(baseline: BaselineScenarioMetric) -> Self {
        ScenarioMetric {
            name: baseline.name,
            users: Value::Plain(baseline.users),
            count: Value::Plain(baseline.count),
            response_time_average: Value::Plain(MillisFloat(
                baseline.response_time_average.unwrap_or(f64::NAN),
            )),
            response_time_minimum: baseline.response_time_minimum.into(),
            response_time_maximum: baseline.response_time_maximum.into(),
            count_per_second: Value::Plain(NullableFloat(baseline.count_per_second)),
            iterations: Value::Plain(NullableFloat(baseline.iterations.unwrap_or(f64::NAN))),
        }
    }
}

/// Baseline error metric with plain values
#[derive(Debug, Deserialize)]
struct BaselineErrorMetric {
    pub method: String,
    pub name: String,
    pub error: String,
    pub occurrences: usize,
}

/// Baseline transaction error metric with plain values
#[derive(Debug, Deserialize)]
struct BaselineTransactionErrorMetric {
    pub transaction: String,
    pub scenario: String,
    pub name: String,
    pub error: String,
    pub occurrences: usize,
}

impl From<BaselineTransactionErrorMetric> for TransactionErrorMetric {
    fn from(baseline: BaselineTransactionErrorMetric) -> Self {
        TransactionErrorMetric {
            transaction: baseline.transaction,
            scenario: baseline.scenario,
            name: baseline.name,
            error: baseline.error,
            occurrences: Value::Plain(baseline.occurrences),
        }
    }
}

impl From<BaselineErrorMetric> for ErrorMetric {
    fn from(baseline: BaselineErrorMetric) -> Self {
        ErrorMetric {
            method: baseline.method,
            name: baseline.name,
            error: baseline.error,
            occurrences: Value::Plain(baseline.occurrences),
        }
    }
}

/// Validate that baseline data is structurally sound.
fn validate_baseline_data(baseline: &ReportData, path_str: &str) -> Result<(), GooseError> {
    // Request metrics (excluding per-status-code breakdown rows) must match
    // response metrics 1:1, and there must be at least one.
    let non_breakdown_request_count = baseline
        .raw_request_metrics
        .iter()
        .filter(|r| !r.is_breakdown)
        .count();
    let response_count = baseline.raw_response_metrics.len();

    if non_breakdown_request_count != response_count {
        return Err(GooseError::InvalidOption {
            option: "--baseline-file".to_string(),
            value: path_str.to_string(),
            detail: format!(
                "Inconsistent baseline data: {} request metrics vs {} response metrics",
                non_breakdown_request_count, response_count
            ),
        });
    }

    if non_breakdown_request_count == 0 {
        return Err(GooseError::InvalidOption {
            option: "--baseline-file".to_string(),
            value: path_str.to_string(),
            detail: "Baseline file contains no request metrics".to_string(),
        });
    }

    Ok(())
}

/// Take a current slice of metrics, and apply correlated baseline metrics.
///
/// This will iterate over all the current metrics, fetch the correlated baseline metrics and call
/// [`DeltaTo::delta_to`] on it. Entries are correlated by the key returned from the function `f`.
fn correlate_deltas<T, F, K>(current: &mut [T], baseline: &[T], f: F)
where
    T: DeltaTo,
    F: Fn(&T) -> K,
    K: Eq + Hash,
{
    let mut current = current
        .iter_mut()
        .map(|request| (f(request), request))
        .collect::<HashMap<_, _>>();
    let previous = baseline
        .iter()
        .map(|request| (f(request), request))
        .collect::<HashMap<_, _>>();

    for (k, v) in &mut current {
        if let Some(previous) = previous.get(k) {
            v.delta_to(previous);
        }
    }
}

#[cfg(test)]
mod test {
    use super::*;
    use crate::metrics::millis::MillisDelta;
    use crate::report::RequestMetric;

    /// Two scenarios with different iteration counts: one user ran the first
    /// 10 times, three users ran the second twice.
    fn two_scenario_metrics() -> GooseMetrics {
        use crate::metrics::ScenarioMetricAggregate;
        let mut metrics = GooseMetrics {
            display_metrics: true,
            duration: 10,
            ..Default::default()
        };
        let mut first = ScenarioMetricAggregate::new(0, "First".into());
        for _ in 0..10 {
            first.update(10, 0);
        }
        let mut second = ScenarioMetricAggregate::new(1, "Second".into());
        second.update(10, 1);
        second.update(10, 2);
        second.users.insert(3);
        metrics.scenarios = vec![first, second];
        metrics
    }

    #[test]
    fn report_aggregated_iterations_match_the_console() {
        let metrics = two_scenario_metrics();
        let data = prepare_data_with_baseline(
            ReportOptions {
                no_transaction_metrics: false,
                no_scenario_metrics: false,
                no_status_codes: false,
            },
            &metrics,
            None,
        );
        let scenarios = data.scenario_metrics.expect("scenario metrics");
        let aggregated = scenarios.last().unwrap();
        assert_eq!(aggregated.name, "Aggregated");
        // 12 runs by 4 users.
        assert_eq!(*aggregated.iterations.value(), 3.0);
        // The console shows the same.
        let console = metrics.to_string();
        let row = console
            .lines()
            .find(|line| line.trim_start().starts_with("Aggregated") && line.contains(" 12 |"))
            .unwrap_or_else(|| panic!("aggregated scenario row in {}", console));
        assert_eq!(row.rsplit('|').next().unwrap().trim(), "3.00");

        // As does the Markdown report, in a table of scenarios.
        let mut markdown = Vec::new();
        crate::report::write_markdown_report(
            &mut markdown,
            prepare_data_with_baseline(
                ReportOptions {
                    no_transaction_metrics: false,
                    no_scenario_metrics: false,
                    no_status_codes: false,
                },
                &metrics,
                None,
            ),
            &[],
        )
        .unwrap();
        let markdown = String::from_utf8(markdown).unwrap();
        let table = &markdown[markdown.find("## Scenario Metrics").unwrap()..];
        assert!(table.contains("\n| Scenario | # Users |"), "{}", table);
        let row = table
            .lines()
            .find(|line| line.starts_with("| Aggregated |"))
            .unwrap();
        assert!(row.ends_with("| 3.00 |"), "{}", row);
    }

    #[test]
    fn delta_value_usize() {
        assert_eq!(100usize.delta(50usize), 50isize);
        assert_eq!(usize::MAX.delta(usize::MAX), 0isize);
        assert_eq!(usize::MAX.delta(0usize), isize::MAX);
        assert_eq!(0usize.delta(usize::MAX), isize::MIN);
    }

    #[test]
    fn correlate_deltas_matches_by_key() {
        let mut current = vec![
            RequestMetric {
                method: "GET".into(),
                name: "/".into(),
                number_of_requests: 200usize.into(),
                number_of_failures: 5usize.into(),
                response_time_average: 50.0f32.into(),
                response_time_minimum: 10usize.into(),
                response_time_maximum: 500usize.into(),
                requests_per_second: 20.0f32.into(),
                failures_per_second: 0.5f32.into(),
                is_breakdown: false,
            },
            RequestMetric {
                method: "POST".into(),
                name: "/api".into(),
                number_of_requests: 100usize.into(),
                number_of_failures: 2usize.into(),
                response_time_average: 80.0f32.into(),
                response_time_minimum: 20usize.into(),
                response_time_maximum: 800usize.into(),
                requests_per_second: 10.0f32.into(),
                failures_per_second: 0.2f32.into(),
                is_breakdown: false,
            },
        ];

        let baseline = vec![RequestMetric {
            method: "GET".into(),
            name: "/".into(),
            number_of_requests: 150usize.into(),
            number_of_failures: 3usize.into(),
            response_time_average: 40.0f32.into(),
            response_time_minimum: 8usize.into(),
            response_time_maximum: 400usize.into(),
            requests_per_second: 15.0f32.into(),
            failures_per_second: 0.3f32.into(),
            is_breakdown: false,
        }];

        correlate_deltas(&mut current, &baseline, |r| {
            (r.method.clone(), r.name.clone())
        });

        // GET / should have deltas applied
        assert_eq!(current[0].number_of_requests.value(), 200);
        assert!(matches!(current[0].number_of_requests, Value::Delta { .. }));

        // POST /api has no baseline match, so it stays Plain
        assert_eq!(current[1].number_of_requests.value(), 100);
        assert!(matches!(current[1].number_of_requests, Value::Plain(_)));
    }

    /// Helper: build a minimal valid baseline JSON string.
    fn minimal_baseline_json(
        requests: usize,
        failures: usize,
        avg_response: f32,
        min_response: usize,
        max_response: usize,
    ) -> String {
        format!(
            r#"{{
                "raw_metrics": {{
                    "hash": 0,
                    "duration": 60,
                    "maximum_users": 10,
                    "total_users": 10,
                    "requests": {{}},
                    "transactions": [],
                    "errors": {{}}
                }},
                "raw_request_metrics": [
                    {{
                        "method": "GET",
                        "name": "/",
                        "number_of_requests": {requests},
                        "number_of_failures": {failures},
                        "response_time_average": {avg_response},
                        "response_time_minimum": {min_response},
                        "response_time_maximum": {max_response},
                        "requests_per_second": 10.0,
                        "failures_per_second": 0.5
                    }}
                ],
                "raw_response_metrics": [
                    {{
                        "method": "GET",
                        "name": "/",
                        "percentile_50": 50,
                        "percentile_60": 60,
                        "percentile_70": 70,
                        "percentile_80": 80,
                        "percentile_90": 90,
                        "percentile_95": 95,
                        "percentile_99": 99,
                        "percentile_100": 100
                    }}
                ]
            }}"#,
        )
    }

    #[test]
    fn load_baseline_file_valid() {
        let path = std::env::temp_dir().join("goose_test_valid_baseline.json");
        std::fs::write(&path, minimal_baseline_json(500, 10, 45.5, 5, 200)).unwrap();
        let result = load_baseline_file(&path);
        std::fs::remove_file(&path).ok();

        let data = result.expect("should load valid baseline");
        assert_eq!(data.raw_request_metrics.len(), 1);
        assert_eq!(data.raw_response_metrics.len(), 1);
        assert_eq!(data.raw_request_metrics[0].number_of_requests.value(), 500);
        assert_eq!(data.raw_request_metrics[0].number_of_failures.value(), 10);
        assert_eq!(data.raw_response_metrics[0].percentile_50.value(), 50);
        assert_eq!(data.raw_response_metrics[0].percentile_100.value(), 100);
        // All values should be Plain (no deltas yet)
        assert!(matches!(
            data.raw_request_metrics[0].number_of_requests,
            Value::Plain(500)
        ));
    }

    #[test]
    fn apply_baseline_deltas_all_metric_types() {
        use crate::report::{
            CORequestMetric, ErrorMetric, ResponseMetric, ScenarioMetric, TransactionMetric,
        };

        let mut current = ReportData {
            raw_metrics: Cow::Owned(GooseMetrics::default()),
            raw_request_metrics: vec![RequestMetric {
                method: "GET".into(),
                name: "/".into(),
                number_of_requests: 200usize.into(),
                number_of_failures: 5usize.into(),
                response_time_average: 50.0f32.into(),
                response_time_minimum: 10usize.into(),
                response_time_maximum: 500usize.into(),
                requests_per_second: 20.0f32.into(),
                failures_per_second: 0.5f32.into(),
                is_breakdown: false,
            }],
            raw_response_metrics: vec![ResponseMetric {
                method: "GET".into(),
                name: "/".into(),
                percentile_50: 50usize.into(),
                percentile_60: 60usize.into(),
                percentile_70: 70usize.into(),
                percentile_80: 80usize.into(),
                percentile_90: 90usize.into(),
                percentile_95: 95usize.into(),
                percentile_99: 99usize.into(),
                percentile_100: 100usize.into(),
            }],
            co_request_metrics: Some(vec![CORequestMetric {
                method: "GET".into(),
                name: "/".into(),
                response_time_average: 55.0f32.into(),
                response_time_standard_deviation: 5.0f32.into(),
                response_time_maximum: 600usize.into(),
            }]),
            co_response_metrics: Some(vec![ResponseMetric {
                method: "GET".into(),
                name: "/".into(),
                percentile_50: 55usize.into(),
                percentile_60: 65usize.into(),
                percentile_70: 75usize.into(),
                percentile_80: 85usize.into(),
                percentile_90: 95usize.into(),
                percentile_95: 100usize.into(),
                percentile_99: 110usize.into(),
                percentile_100: 120usize.into(),
            }]),
            transaction_metrics: Some(vec![TransactionMetric {
                is_scenario: false,
                transaction: "LoadTest".into(),
                name: "front page".into(),
                number_of_requests: 200usize.into(),
                number_of_failures: 5usize.into(),
                response_time_average: Some(50.0f32.into()),
                response_time_minimum: 10usize.into(),
                response_time_maximum: 500usize.into(),
                requests_per_second: Some(20.0f32.into()),
                failures_per_second: Some(0.5f32.into()),
            }]),
            scenario_metrics: Some(vec![ScenarioMetric {
                name: "LoadTest".into(),
                users: 10usize.into(),
                count: 200usize.into(),
                response_time_average: 50.0f32.into(),
                response_time_minimum: 10usize.into(),
                response_time_maximum: 500usize.into(),
                count_per_second: 20.0f32.into(),
                iterations: 5.0f32.into(),
            }]),
            status_code_metrics: None,
            errors: Some(vec![ErrorMetric {
                method: "GET".into(),
                name: "/".into(),
                error: "503 Service Unavailable".into(),
                occurrences: 5usize.into(),
            }]),
            transaction_errors: None,
            coordinated_omission_metrics: None,
        };

        // Build a baseline with different values
        let baseline = ReportData {
            raw_metrics: Cow::Owned(GooseMetrics::default()),
            raw_request_metrics: vec![RequestMetric {
                method: "GET".into(),
                name: "/".into(),
                number_of_requests: 150usize.into(),
                number_of_failures: 3usize.into(),
                response_time_average: 40.0f32.into(),
                response_time_minimum: 8usize.into(),
                response_time_maximum: 400usize.into(),
                requests_per_second: 15.0f32.into(),
                failures_per_second: 0.3f32.into(),
                is_breakdown: false,
            }],
            raw_response_metrics: vec![ResponseMetric {
                method: "GET".into(),
                name: "/".into(),
                percentile_50: 40usize.into(),
                percentile_60: 50usize.into(),
                percentile_70: 60usize.into(),
                percentile_80: 70usize.into(),
                percentile_90: 80usize.into(),
                percentile_95: 85usize.into(),
                percentile_99: 90usize.into(),
                percentile_100: 95usize.into(),
            }],
            co_request_metrics: Some(vec![CORequestMetric {
                method: "GET".into(),
                name: "/".into(),
                response_time_average: 45.0f32.into(),
                response_time_standard_deviation: 4.0f32.into(),
                response_time_maximum: 500usize.into(),
            }]),
            co_response_metrics: Some(vec![ResponseMetric {
                method: "GET".into(),
                name: "/".into(),
                percentile_50: 45usize.into(),
                percentile_60: 55usize.into(),
                percentile_70: 65usize.into(),
                percentile_80: 75usize.into(),
                percentile_90: 85usize.into(),
                percentile_95: 90usize.into(),
                percentile_99: 100usize.into(),
                percentile_100: 110usize.into(),
            }]),
            transaction_metrics: Some(vec![TransactionMetric {
                is_scenario: false,
                transaction: "LoadTest".into(),
                name: "front page".into(),
                number_of_requests: 150usize.into(),
                number_of_failures: 3usize.into(),
                response_time_average: Some(40.0f32.into()),
                response_time_minimum: 8usize.into(),
                response_time_maximum: 400usize.into(),
                requests_per_second: Some(15.0f32.into()),
                failures_per_second: Some(0.3f32.into()),
            }]),
            scenario_metrics: Some(vec![ScenarioMetric {
                name: "LoadTest".into(),
                users: 8usize.into(),
                count: 150usize.into(),
                response_time_average: 40.0f32.into(),
                response_time_minimum: 8usize.into(),
                response_time_maximum: 400usize.into(),
                count_per_second: 15.0f32.into(),
                iterations: 4.0f32.into(),
            }]),
            status_code_metrics: None,
            errors: Some(vec![ErrorMetric {
                method: "GET".into(),
                name: "/".into(),
                error: "503 Service Unavailable".into(),
                occurrences: 3usize.into(),
            }]),
            transaction_errors: None,
            coordinated_omission_metrics: None,
        };

        apply_baseline_deltas(&mut current, &baseline);

        // Request metrics: 200 - 150 = +50
        assert!(matches!(
            current.raw_request_metrics[0].number_of_requests,
            Value::Delta {
                value: 200,
                delta: 50
            }
        ));
        // Response percentile: 50 - 40 = +10
        assert!(matches!(
            current.raw_response_metrics[0].percentile_50,
            Value::Delta {
                value: Millis(50_000),
                delta: MillisDelta(10_000)
            }
        ));
        // CO request: 600 - 500 = +100
        assert!(matches!(
            current.co_request_metrics.as_ref().unwrap()[0].response_time_maximum,
            Value::Delta {
                value: Millis(600_000),
                delta: MillisDelta(100_000)
            }
        ));
        // CO response percentile: 55 - 45 = +10
        assert!(matches!(
            current.co_response_metrics.as_ref().unwrap()[0].percentile_50,
            Value::Delta {
                value: Millis(55_000),
                delta: MillisDelta(10_000)
            }
        ));
        // Transaction: 200 - 150 = +50
        assert!(matches!(
            current.transaction_metrics.as_ref().unwrap()[0].number_of_requests,
            Value::Delta {
                value: 200,
                delta: 50
            }
        ));
        // Scenario: 10 - 8 = +2
        assert!(matches!(
            current.scenario_metrics.as_ref().unwrap()[0].users,
            Value::Delta {
                value: 10,
                delta: 2
            }
        ));
        // Error: 5 - 3 = +2
        assert!(matches!(
            current.errors.as_ref().unwrap()[0].occurrences,
            Value::Delta { value: 5, delta: 2 }
        ));
    }

    #[test]
    fn round_trip_serialize_then_load_as_baseline() {
        use crate::report::ResponseMetric;

        // Build a ReportData, serialize to JSON, load as baseline
        let mut metrics = GooseMetrics::default();
        metrics
            .history
            .push(crate::test_plan::TestPlanHistory::step(
                crate::test_plan::TestPlanStepAction::Increasing,
                0,
            ));
        let original = ReportData {
            raw_metrics: Cow::Owned(metrics),
            raw_request_metrics: vec![RequestMetric {
                method: "POST".into(),
                name: "/api/submit".into(),
                number_of_requests: 1000usize.into(),
                number_of_failures: 25usize.into(),
                response_time_average: 120.5f32.into(),
                response_time_minimum: 15usize.into(),
                response_time_maximum: 3000usize.into(),
                requests_per_second: 16.7f32.into(),
                failures_per_second: 0.42f32.into(),
                is_breakdown: false,
            }],
            raw_response_metrics: vec![ResponseMetric {
                method: "POST".into(),
                name: "/api/submit".into(),
                percentile_50: 100usize.into(),
                percentile_60: 110usize.into(),
                percentile_70: 130usize.into(),
                percentile_80: 150usize.into(),
                percentile_90: 200usize.into(),
                percentile_95: 500usize.into(),
                percentile_99: 1500usize.into(),
                percentile_100: 3000usize.into(),
            }],
            co_request_metrics: None,
            co_response_metrics: None,
            scenario_metrics: None,
            transaction_metrics: None,
            status_code_metrics: None,
            errors: None,
            transaction_errors: None,
            coordinated_omission_metrics: None,
        };

        let json = serde_json::to_string_pretty(&original).unwrap();

        let path = std::env::temp_dir().join("goose_test_roundtrip.json");
        std::fs::write(&path, &json).unwrap();
        let loaded = load_baseline_file(&path);
        std::fs::remove_file(&path).ok();

        let data = loaded.expect("round-trip should succeed");
        assert_eq!(data.raw_request_metrics.len(), 1);
        assert_eq!(data.raw_request_metrics[0].method, "POST");
        assert_eq!(data.raw_request_metrics[0].name, "/api/submit");
        assert_eq!(data.raw_request_metrics[0].number_of_requests.value(), 1000);
        assert_eq!(data.raw_response_metrics[0].percentile_99.value(), 1500);
        // The test plan history is kept, so a report rendered from the JSON
        // has a plan overview.
        assert_eq!(data.raw_metrics.history.len(), 1);
    }

    #[test]
    fn load_baseline_file_from_run_directory() {
        let dir = std::env::temp_dir().join(format!(
            "goose_test_baseline_run_dir_{}",
            std::process::id()
        ));
        std::fs::create_dir_all(&dir).unwrap();
        std::fs::write(
            dir.join(crate::runs::REPORT_JSON),
            minimal_baseline_json(500, 10, 45.5, 5, 200),
        )
        .unwrap();
        let result = load_baseline_file(&dir);
        std::fs::remove_dir_all(&dir).ok();

        let data = result.expect("should load report.json from the run directory");
        assert_eq!(data.raw_request_metrics[0].number_of_requests.value(), 500);
    }

    #[test]
    fn load_baseline_file_invalid_path() {
        let result = load_baseline_file("/nonexistent/path.json");
        assert!(result.is_err());
    }

    #[test]
    fn load_baseline_file_invalid_json() {
        let path = std::env::temp_dir().join("goose_test_invalid.json");
        std::fs::write(&path, "not valid json").unwrap();
        let result = load_baseline_file(&path);
        std::fs::remove_file(&path).ok();
        assert!(result.is_err());
    }

    #[test]
    fn load_baseline_file_empty_metrics() {
        let path = std::env::temp_dir().join("goose_test_empty.json");
        std::fs::write(
            &path,
            r#"{
                "raw_metrics": {
                    "hash": 0,
                    "duration": 10,
                    "maximum_users": 1,
                    "total_users": 1,
                    "requests": {},
                    "transactions": [],
                    "errors": {}
                },
                "raw_request_metrics": [],
                "raw_response_metrics": []
            }"#,
        )
        .unwrap();
        let result = load_baseline_file(&path);
        std::fs::remove_file(&path).ok();
        match result {
            Err(GooseError::InvalidOption { detail, .. }) => {
                assert!(
                    detail.contains("no request metrics"),
                    "unexpected detail: {}",
                    detail
                );
            }
            other => panic!("expected InvalidOption error, got: {:?}", other),
        }
    }
}