package core

import (
	"errors"
	"strings"
	"testing"
)

func TestParseDocID(t *testing.T) {
	tests := []struct {
		name       string
		in         string
		wantPrefix string
		wantSeq    string
		ok         bool
	}{
		{"spec", "SPEC-0007", "SPEC", "0007", true},
		{"rfc", "RFC-1", "RFC", "1", true},
		{"single letter prefix", "X-42", "X", "42", true},
		{"digits in prefix", "C4-0001", "C4", "0001", true},
		{"all zeros", "SPEC-0000", "SPEC", "0000", true},
		{"max prefix", strings.Repeat("A", MaxDocIDPrefixLen) + "-1", strings.Repeat("A", MaxDocIDPrefixLen), "1", true},
		{"max seq", "SPEC-" + strings.Repeat("9", MaxDocIDSeqLen), "SPEC", strings.Repeat("9", MaxDocIDSeqLen), true},

		{"empty", "", "", "", false},
		{"no separator", "SPEC0007", "", "", false},
		{"two separators", "HOME-OPS-0001", "", "", false},
		{"double dash", "SPEC--1", "", "", false},
		{"empty prefix", "-0007", "", "", false},
		{"empty seq", "SPEC-", "", "", false},
		{"lowercase prefix", "spec-0007", "", "", false},
		{"mixed case prefix", "Spec-0007", "", "", false},
		{"digit-leading prefix", "0SPEC-1", "", "", false},
		{"underscore in prefix", "SPEC_A-1", "", "", false},
		{"dot in prefix", "SPEC.A-1", "", "", false},
		{"non-digit seq", "SPEC-007a", "", "", false},
		{"signed seq", "SPEC-+1", "", "", false},
		{"hex seq", "SPEC-0x7", "", "", false},
		{"prefix too long", strings.Repeat("A", MaxDocIDPrefixLen+1) + "-1", "", "", false},
		{"seq too long", "SPEC-" + strings.Repeat("9", MaxDocIDSeqLen+1), "", "", false},
		{"leading space", " SPEC-0007", "", "", false},
		{"trailing space", "SPEC-0007 ", "", "", false},
		{"inner space", "SPEC - 0007", "", "", false},
		{"newline", "SPEC-0007\n", "", "", false},
		// Homograph: Cyrillic С/Р/Е/С look identical to Latin in most fonts.
		// Accepting them would let two visually identical IDs both register.
		{"cyrillic homograph", "СПЕС-0007", "", "", false},
		{"fullwidth digits", "SPEC-０００７", "", "", false},
		{"arabic-indic digits", "SPEC-٠٠٠٧", "", "", false},
		{"path injection", "SPEC-0007/../x", "", "", false},
	}
	for _, tc := range tests {
		t.Run(tc.name, func(t *testing.T) {
			id, err := ParseDocID(tc.in)
			if (err == nil) != tc.ok {
				t.Fatalf("ParseDocID(%q) = %+v, %v, want ok=%v", tc.in, id, err, tc.ok)
			}
			if !tc.ok {
				if !errors.Is(err, ErrInvalidDocID) {
					t.Fatalf("error %v is not ErrInvalidDocID", err)
				}
				return
			}
			if id.Prefix != tc.wantPrefix || id.Seq != tc.wantSeq {
				t.Fatalf("ParseDocID(%q) = %+v, want {%q %q}", tc.in, id, tc.wantPrefix, tc.wantSeq)
			}
			if got := id.String(); got != tc.in {
				t.Fatalf("String() = %q, want round-trip %q", got, tc.in)
			}
		})
	}
}

// Leading zeros are significant: the registry is global and "SPEC-7" is a
// different key from "SPEC-0007". Normalizing them together would silently
// merge two documents.
func TestDocIDLeadingZerosAreSignificant(t *testing.T) {
	a, err := ParseDocID("SPEC-7")
	if err != nil {
		t.Fatal(err)
	}
	b, err := ParseDocID("SPEC-0007")
	if err != nil {
		t.Fatal(err)
	}
	if a == b {
		t.Fatalf("SPEC-7 and SPEC-0007 must not compare equal, got %+v", a)
	}
	if a.String() == b.String() {
		t.Fatal("SPEC-7 and SPEC-0007 must not render identically")
	}
}

func TestValidateDocID(t *testing.T) {
	if err := ValidateDocID("SPEC-0007"); err != nil {
		t.Fatalf("ValidateDocID(SPEC-0007) = %v, want nil", err)
	}
	if err := ValidateDocID("spec-0007"); !errors.Is(err, ErrInvalidDocID) {
		t.Fatalf("ValidateDocID(spec-0007) = %v, want ErrInvalidDocID", err)
	}
}