package rules

import (
	"encoding/json"
	"testing"
)

func TestArchiversCanBeNull(t *testing.T) {
	tests := []struct {
		name    string
		json    string
		wantNil bool
		check   func(t *testing.T, rule Rule)
	}{
		{
			name:    "mimetype rule with null extractors",
			json:    `{"mimetype": "text/html", "extractors": null}`,
			wantNil: true,
			check: func(t *testing.T, rule Rule) {
				mr, ok := rule.(*MimetypeRule)
				if !ok {
					t.Fatalf("expected MimetypeRule, got %T", rule)
				}
				if mr.Archivers != nil {
					t.Errorf("Archivers = %v, want nil", mr.Archivers)
				}
			},
		},
		{
			name:    "mimetype rule without extractors field",
			json:    `{"mimetype": "text/html"}`,
			wantNil: true,
			check: func(t *testing.T, rule Rule) {
				mr, ok := rule.(*MimetypeRule)
				if !ok {
					t.Fatalf("expected MimetypeRule, got %T", rule)
				}
				if mr.Archivers != nil {
					t.Errorf("Archivers = %v, want nil", mr.Archivers)
				}
			},
		},
		{
			name:    "hostname rule with null extractors",
			json:    `{"hostname": "example.com", "extractors": null}`,
			wantNil: true,
			check: func(t *testing.T, rule Rule) {
				hr, ok := rule.(*HostnameRule)
				if !ok {
					t.Fatalf("expected HostnameRule, got %T", rule)
				}
				if hr.Archivers != nil {
					t.Errorf("Archivers = %v, want nil", hr.Archivers)
				}
			},
		},
		{
			name:    "mimetype rule with extractors",
			json:    `{"mimetype": "text/html", "extractors": [{"key": "obelisk"}]}`,
			wantNil: false,
			check: func(t *testing.T, rule Rule) {
				mr, ok := rule.(*MimetypeRule)
				if !ok {
					t.Fatalf("expected MimetypeRule, got %T", rule)
				}
				if mr.Archivers == nil {
					t.Error("Archivers is nil, want non-nil")
				}
				if len(mr.Archivers) != 1 || mr.Archivers[0].Key != "obelisk" {
					t.Errorf("Archivers = %v, want [{key: obelisk}]", mr.Archivers)
				}
			},
		},
		{
			name:    "and rule with null extractors in child",
			json:    `{"and": [{"mimetype": "text/html"}], "extractors": [{"key": "obelisk"}]}`,
			wantNil: false,
			check: func(t *testing.T, rule Rule) {
				ar, ok := rule.(*AndRule)
				if !ok {
					t.Fatalf("expected AndRule, got %T", rule)
				}
				if len(ar.Rules) != 1 {
					t.Errorf("Rules length = %d, want 1", len(ar.Rules))
				}
				// Child rule should have nil extractors
				mr, ok := ar.Rules[0].(*MimetypeRule)
				if !ok {
					t.Fatalf("expected MimetypeRule child, got %T", ar.Rules[0])
				}
				if mr.Archivers != nil {
					t.Errorf("Child rule Archivers = %v, want nil", mr.Archivers)
				}
				// Root rule should have extractors
				if ar.Archivers == nil {
					t.Error("Root rule Archivers is nil, want non-nil")
				}
			},
		},
	}

	for _, tt := range tests {
		t.Run(tt.name, func(t *testing.T) {
			rule, err := UnmarshalRule([]byte(tt.json))
			if err != nil {
				t.Fatalf("UnmarshalRule() error = %v", err)
			}
			if rule == nil {
				t.Fatal("UnmarshalRule() returned nil rule")
			}
			if tt.check != nil {
				tt.check(t, rule)
			}
		})
	}
}

func TestArchiversOmitEmpty(t *testing.T) {
	// Test that rules without extractors don't include the field in JSON
	tests := []struct {
		name  string
		rule  Rule
		check func(t *testing.T, jsonStr string)
	}{
		{
			name: "mimetype rule without extractors",
			rule: &MimetypeRule{
				Mimetype:  "text/html",
				Archivers: nil,
			},
			check: func(t *testing.T, jsonStr string) {
				// Should not contain "extractors" field when nil
				if jsonStr == "" {
					t.Error("JSON is empty")
				}
				// When extractors is nil and omitempty is set, it should be omitted
				// But Go's json package will include null if the field is explicitly set
				// Let's check that it's either omitted or null
				hasExtractors := contains(jsonStr, "extractors")
				if hasExtractors && !contains(jsonStr, `"extractors":null`) {
					t.Errorf("JSON contains extractors but not as null: %s", jsonStr)
				}
			},
		},
		{
			name: "hostname rule without extractors",
			rule: &HostnameRule{
				Hostname:  "example.com",
				Archivers: nil,
			},
			check: func(t *testing.T, jsonStr string) {
				hasExtractors := contains(jsonStr, "extractors")
				if hasExtractors && !contains(jsonStr, `"extractors":null`) {
					t.Errorf("JSON contains extractors but not as null: %s", jsonStr)
				}
			},
		},
	}

	for _, tt := range tests {
		t.Run(tt.name, func(t *testing.T) {
			jsonBytes, err := json.Marshal(tt.rule)
			if err != nil {
				t.Fatalf("Marshal() error = %v", err)
			}
			if tt.check != nil {
				tt.check(t, string(jsonBytes))
			}
		})
	}
}

func contains(s, substr string) bool {
	for i := 0; i <= len(s)-len(substr); i++ {
		if s[i:i+len(substr)] == substr {
			return true
		}
	}
	return false
}