package iace

import (
	"math"
	"strconv"
	"strings"
	"testing"
)

// These tests codify the May-built-but-never-verified OSHA minimum-distance
// library: that its public-domain values convert correctly, that the
// measure→distance links point at real measures and real distances, and that
// a "value_source" link's OSHA figure actually appears in the measure prose
// (the consistency the audit asked for).

const inchToMM = 25.4

func TestOSHAMinimumDistances_ConversionAndLicense(t *testing.T) {
	dists := GetOSHAMinimumDistances()
	if len(dists) == 0 {
		t.Fatal("OSHA minimum-distance library is empty")
	}
	seen := map[string]bool{}
	for _, d := range dists {
		if seen[d.ID] {
			t.Errorf("duplicate distance ID %q", d.ID)
		}
		seen[d.ID] = true

		if d.License == "" || d.SourceCFR == "" || d.Context == "" {
			t.Errorf("%s: missing license/source/context: %+v", d.ID, d)
		}

		// Inch → mm conversions must be mathematically exact (within rounding).
		if d.OriginalUnit == UnitInch {
			checkConv := func(label string, orig, exact float64) {
				if orig == 0 && exact == 0 {
					return
				}
				if math.Abs(orig*inchToMM-exact) > 0.05 {
					t.Errorf("%s: %s conversion off: %.3f in → %.3f mm (expected %.3f)",
						d.ID, label, orig, exact, orig*inchToMM)
				}
			}
			checkConv("value", d.OriginalValue, d.ExactMM)
			checkConv("min", d.OriginalMin, d.ExactMinMM)
			checkConv("max", d.OriginalMax, d.ExactMaxMM)
		}

		// Safe-side rounding must stay near the exact value (≤5 mm grid).
		if d.ExactMM > 0 && d.RecommendedMM > 0 {
			if math.Abs(float64(d.RecommendedMM)-d.ExactMM) > 5 {
				t.Errorf("%s: recommended %d mm too far from exact %.2f mm",
					d.ID, d.RecommendedMM, d.ExactMM)
			}
		}
	}
}

func TestMeasureDistanceLinks_Integrity(t *testing.T) {
	measures := map[string]ProtectiveMeasureEntry{}
	for _, m := range GetProtectiveMeasureLibrary() {
		measures[m.ID] = m
	}

	links := AllMeasureDistanceLinks()
	if len(links) == 0 {
		t.Fatal("no measure→distance links declared")
	}
	for _, l := range links {
		if _, ok := measures[l.MeasureID]; !ok {
			t.Errorf("link references unknown measure %q", l.MeasureID)
		}
		if l.Relation != LinkValueSource && l.Relation != LinkCrossRef {
			t.Errorf("link %q has invalid relation %q", l.MeasureID, l.Relation)
		}
		if len(l.DistanceIDs) == 0 {
			t.Errorf("link %q has no distance IDs", l.MeasureID)
		}
		for _, id := range l.DistanceIDs {
			if _, ok := GetMinimumDistanceByID(id); !ok {
				t.Errorf("link %q references unknown distance %q", l.MeasureID, id)
			}
		}
		// The resolver must return exactly the linked distances.
		if got := len(MinimumDistancesForMeasure(l.MeasureID)); got != len(l.DistanceIDs) {
			t.Errorf("resolver for %q returned %d, expected %d", l.MeasureID, got, len(l.DistanceIDs))
		}
	}
}

func TestMeasureDistanceLinks_ValueSourceProseConsistency(t *testing.T) {
	measures := map[string]ProtectiveMeasureEntry{}
	for _, m := range GetProtectiveMeasureLibrary() {
		measures[m.ID] = m
	}

	for _, l := range AllMeasureDistanceLinks() {
		if l.Relation != LinkValueSource {
			continue // cross-refs legitimately use an EU value in prose
		}
		m := measures[l.MeasureID]
		text := strings.ToLower(m.Name + " " + m.Description + " " + strings.Join(m.Examples, " "))
		text = strings.ReplaceAll(text, ".", "") // "1.600" → "1600"

		for _, id := range l.DistanceIDs {
			md, _ := GetMinimumDistanceByID(id)
			if !proseMentionsDistance(text, md) {
				t.Errorf("value_source measure %q does not mention any value of linked distance %q "+
					"— prose has drifted from the OSHA source", l.MeasureID, id)
			}
		}
	}
}

// proseMentionsDistance reports whether the (dot-stripped, lowercased) measure
// text contains a numeric form of the distance's value, formula or recommended mm.
func proseMentionsDistance(text string, md MinimumDistance) bool {
	candidates := []int{}
	if md.FormulaMMPerSecond > 0 {
		candidates = append(candidates, int(math.Round(md.FormulaMMPerSecond)))
	}
	if md.RecommendedMM > 0 {
		candidates = append(candidates, md.RecommendedMM)
	}
	if md.RecommendedMinMM > 0 {
		candidates = append(candidates, md.RecommendedMinMM)
	}
	for _, n := range candidates {
		if strings.Contains(text, strconv.Itoa(n)) {
			return true
		}
	}
	return false
}