use std::collections::BTreeSet;

use crank_metrics::{
    HTTP_ROUTE_DOMAIN, HttpRoute, LabelClass, LabelDomain, MAX_LOGICAL_SERIES_PER_PROCESS,
    MAX_PRODUCT_LABELS_PER_FAMILY, MAX_RENDERED_SERIES_PER_PROCESS, METRIC_SCHEMA_VERSION,
    MetricDefinition, MetricKind, MetricProcess, MetricService, MetricUnit, metric_schema,
    metric_schema_for_service, render_metric_schema_json, schema_budget, validate_budget,
    validate_schema,
};

#[test]
fn schema_v1_is_complete_deterministic_and_inside_the_frozen_budget() {
    assert_eq!(METRIC_SCHEMA_VERSION, 1);
    assert_eq!(metric_schema().len(), 23);

    let budget = schema_budget().expect("canonical schema must be valid");
    assert!(budget.logical_series <= MAX_LOGICAL_SERIES_PER_PROCESS);
    assert!(budget.rendered_series <= MAX_RENDERED_SERIES_PER_PROCESS);

    for definition in metric_schema() {
        assert!(!definition.description.trim().is_empty());
        assert!(definition.labels.len() <= MAX_PRODUCT_LABELS_PER_FAMILY);
        assert!(!definition.processes.is_empty());
        assert_eq!(definition.labels.len(), definition.label_domains.len());
        assert!(definition.label_domains.iter().all(|domain| {
            !domain.values.is_empty()
                && domain.values.iter().all(|value| !value.is_empty())
                && domain.values.iter().copied().collect::<BTreeSet<_>>().len()
                    == domain.values.len()
        }));
        if definition.kind.as_str() == "histogram" {
            assert!(!definition.buckets.is_empty());
            assert!(definition.buckets.windows(2).all(|pair| pair[0] < pair[1]));
        } else {
            assert!(definition.buckets.is_empty());
        }
    }

    let first = render_metric_schema_json().expect("schema renders");
    let second = render_metric_schema_json().expect("schema renders deterministically");
    assert_eq!(first, second);
    assert!(first.len() < 65_536);
    assert!(!first.contains("trace_id"));
    assert!(!first.contains("request_id"));
}

#[test]
fn frozen_budget_edges_are_exact() {
    assert!(validate_budget(4_999, 14_999).is_ok());
    assert!(validate_budget(5_000, 15_000).is_ok());
    assert!(validate_budget(5_001, 15_000).is_err());
    assert!(validate_budget(5_000, 15_001).is_err());
    assert_eq!(crank_metrics::max_exemplar_slots(), 9_170);
}

#[test]
fn every_registered_route_round_trips_without_dynamic_segments() {
    assert_eq!(HTTP_ROUTE_DOMAIN.len(), 57);
    for route in HTTP_ROUTE_DOMAIN {
        assert_eq!(HttpRoute::from_matched_path(route).as_str(), *route);
        assert!(!route.contains("trace_id"));
        assert!(!route.contains("request_id"));
    }
}

#[test]
fn canonical_schema_validation_reports_its_category() {
    assert_eq!(
        schema_budget(),
        Ok(crank_metrics::SchemaBudget {
            logical_series: 4_513,
            rendered_series: 14_338
        })
    );
}

#[test]
fn exact_budget_math_counts_histogram_bucket_sum_and_count_series() {
    for definition in metric_schema() {
        let logical = definition
            .label_domains
            .iter()
            .map(|domain| domain.values.len())
            .product::<usize>();
        let logical = logical.max(1);
        let rendered = if definition.kind.as_str() == "histogram" {
            logical * (definition.buckets.len() + 3)
        } else {
            logical
        };
        assert_eq!(
            definition.max_logical_series, logical,
            "{}",
            definition.name
        );
        assert_eq!(
            definition.max_rendered_series, rendered,
            "{}",
            definition.name
        );
    }
}

#[test]
fn prometheus_reserved_and_digit_prefixed_label_names_are_rejected() {
    static DOMAIN: LabelDomain = LabelDomain {
        name: "valid",
        class: LabelClass::ProductClosed,
        values: &["value"],
    };
    for label in ["1invalid", "__reserved"] {
        let mut domain = DOMAIN;
        domain.name = label;
        let definition = MetricDefinition {
            name: "crank_test_total",
            kind: MetricKind::Counter,
            unit: MetricUnit::Count,
            labels: Box::leak(vec![label].into_boxed_slice()),
            label_domains: Box::leak(vec![domain].into_boxed_slice()),
            buckets: &[],
            processes: &[MetricProcess::AdminApi],
            max_logical_series: 1,
            max_rendered_series: 1,
            description: "test metric",
        };
        assert!(validate_schema(&[definition]).is_err(), "accepted {label}");
    }
}

#[test]
fn process_projection_excludes_mcp_only_metrics_from_admin() {
    let admin = metric_schema_for_service(MetricService::AdminApi)
        .map(|definition| definition.name)
        .collect::<BTreeSet<_>>();
    let mcp = metric_schema_for_service(MetricService::McpServer)
        .map(|definition| definition.name)
        .collect::<BTreeSet<_>>();
    assert!(!admin.contains("crank_mcp_active_sessions"));
    assert!(!admin.contains("crank_catalog_tools"));
    assert!(mcp.contains("crank_mcp_active_sessions"));
    assert!(admin.contains("crank_http_requests_total"));
    assert!(mcp.contains("crank_http_requests_total"));
}

#[test]
fn registered_admin_and_mcp_routes_are_exactly_the_schema_domain() {
    let admin_source = include_str!("../../../apps/admin-api/src/app.rs");
    let mcp_source = include_str!("../../crank-community-mcp/src/app.rs");
    let auth = ["/login", "/logout", "/session", "/profile", "/password"];
    let admin_root = ["/capabilities", "/workspaces", "/workspaces/{workspace_id}"];
    let mut actual = BTreeSet::from(["unmatched".to_owned()]);
    for route in route_literals(admin_source) {
        let canonical = if matches!(route.as_str(), "/health" | "/ready") {
            route
        } else if auth.contains(&route.as_str()) {
            format!("/api/auth{route}")
        } else if admin_root.contains(&route.as_str()) {
            format!("/api/admin{route}")
        } else {
            format!("/api/admin/workspaces/{{workspace_id}}{route}")
        };
        actual.insert(canonical);
    }
    actual.extend(route_literals(mcp_source));
    let expected = HTTP_ROUTE_DOMAIN
        .iter()
        .map(|route| (*route).to_owned())
        .collect::<BTreeSet<_>>();
    assert_eq!(actual, expected);
}

fn route_literals(source: &str) -> Vec<String> {
    let mut routes = Vec::new();
    let mut remaining = source;
    while let Some(offset) = remaining.find(".route(") {
        remaining = &remaining[offset + ".route(".len()..];
        let Some(start) = remaining.find('"') else {
            break;
        };
        let after_start = &remaining[start + 1..];
        let Some(end) = after_start.find('"') else {
            break;
        };
        routes.push(after_start[..end].to_owned());
        remaining = &after_start[end + 1..];
    }
    routes
}