package missionclass

import "testing"

// codesOf extracts just the mission codes from a slice of hits, preserving order.
func codesOf(hits []Hit) []string {
	out := make([]string, 0, len(hits))
	for _, h := range hits {
		out = append(out, h.Code)
	}
	return out
}

// equal reports whether two string slices are identical in length, order, and contents. nil and an
// empty slice compare equal so a no match (nil) matches the want of nil.
func equal(a, b []string) bool {
	if len(a) != len(b) {
		return false
	}
	for i := range a {
		if a[i] != b[i] {
			return false
		}
	}
	return true
}

func contains(s []string, want string) bool {
	for _, v := range s {
		if v == want {
			return true
		}
	}
	return false
}

func TestClassifyKeyword(t *testing.T) {
	cases := []struct {
		text string
		want []string // mission codes, in Codes order
	}{
		{"Provide SIGINT collection and COMSEC support", []string{"SIGINT", "COMSEC"}},
		{"signals intelligence analysis for the customer", []string{"SIGINT"}},
		{"satellite command and control operations", []string{"SAT_C2"}},
		{"a cross domain solution accreditation effort", []string{"CDS"}},
		{"general administrative support services", nil},
		{"", nil},
		// bare acronym must not match inside a longer word
		{"the cdsa framework", nil},
	}
	for _, tc := range cases {
		got := codesOf(ClassifyKeyword(tc.text))
		if !equal(got, tc.want) {
			t.Fatalf("ClassifyKeyword(%q) = %v, want %v", tc.text, got, tc.want)
		}
	}
}

func TestClassifyAlias(t *testing.T) {
	idx := NewAliasIndex(map[string]string{
		"sigint analyst":       "SIGINT",
		"signals intelligence": "SIGINT",
		"comsec custodian":     "COMSEC",
	})
	got := codesOf(ClassifyAlias("seeking a SIGINT Analyst and a COMSEC Custodian", idx))
	want := []string{"SIGINT", "COMSEC"}
	if !equal(got, want) {
		t.Fatalf("ClassifyAlias = %v, want %v", got, want)
	}

	// Empty text yields no hit.
	if got := ClassifyAlias("", idx); len(got) != 0 {
		t.Fatalf("ClassifyAlias of empty text should yield nothing, got %v", got)
	}

	// The alias mechanism and evidence phrase are recorded for traceability.
	hits := ClassifyAlias("hiring a SIGINT Analyst", idx)
	if len(hits) != 1 || hits[0].Mechanism != MechAlias || hits[0].Evidence != "sigint analyst" {
		t.Fatalf("alias hit must carry the alias mechanism and matched phrase, got %+v", hits)
	}
}

func TestClassifyCodes(t *testing.T) {
	// The AC PSC prefix (R&D, National Defense) is the one curated mapping: it yields SIGINT and EW.
	got := codesOf(ClassifyCodes("AC12", ""))
	if !contains(got, "SIGINT") || !contains(got, "EW") {
		t.Fatalf("AC PSC prefix must map to SIGINT and EW, got %v", got)
	}
	if len(got) != 2 {
		t.Fatalf("AC PSC prefix must yield exactly the two curated codes, got %v", got)
	}
	// The hits carry the psc mechanism and the uppercased code as evidence.
	for _, h := range ClassifyCodes("ac12", "") {
		if h.Mechanism != MechPSC || h.Evidence != "AC12" {
			t.Fatalf("psc hit must carry the psc mechanism and uppercased code, got %+v", h)
		}
	}
	// An unknown PSC and NAICS yields no mission rather than a wrong one.
	if got := ClassifyCodes("ZZZZ", "999999"); len(got) != 0 {
		t.Fatalf("unknown PSC and NAICS should yield no mission, got %v", got)
	}
	// A deliberately broad NAICS that is intentionally empty yields nothing.
	if got := ClassifyCodes("", "541330"); len(got) != 0 {
		t.Fatalf("intentionally broad NAICS 541330 must yield no mission, got %v", got)
	}
}

func TestClassifyUnion(t *testing.T) {
	// "case officer" carries HUMINT in the alias layer but has no keyword form, so the alias mechanism is
	// the only path to HUMINT and genuinely wins (it is not shadowed by a keyword hit).
	idx := NewAliasIndex(map[string]string{
		"case officer": "HUMINT",
	})
	// A record with a keyword hit (SIGINT), an alias only hit (HUMINT via case officer), and a code hit
	// (AC prefix => SIGINT, EW). SIGINT is reached by both keyword and code; the union dedupes by code and
	// the keyword mechanism wins because keyword is unioned first.
	hits := Classify("SIGINT collection led by a Case Officer", "AC10", "", idx)
	got := codesOf(hits)
	want := []string{"SIGINT", "HUMINT", "EW"}
	if !equal(got, want) {
		t.Fatalf("Classify union = %v, want %v", got, want)
	}
	byCode := map[string]Hit{}
	for _, h := range hits {
		byCode[h.Code] = h
	}
	if byCode["SIGINT"].Mechanism != MechKeyword {
		t.Fatalf("SIGINT was reached by keyword and code, keyword must win, got %q", byCode["SIGINT"].Mechanism)
	}
	if byCode["HUMINT"].Mechanism != MechAlias {
		t.Fatalf("HUMINT came only from the alias layer, got %q", byCode["HUMINT"].Mechanism)
	}
	if byCode["EW"].Mechanism != MechPSC {
		t.Fatalf("EW came only from the PSC crosswalk, got %q", byCode["EW"].Mechanism)
	}
}