package rules

import (
	"net/http"
	"testing"
)

func TestHasBodyRules(t *testing.T) {
	tests := []struct {
		name string
		rs   []Rule
		want bool
	}{
		{"empty", nil, false},
		{"header rule only", []Rule{{Enabled: true, Part: "header"}}, false},
		{"body rule enabled", []Rule{{Enabled: true, Part: "body"}}, true},
		{"body rule disabled", []Rule{{Enabled: false, Part: "body"}}, false},
		{"mixed, one enabled body rule", []Rule{
			{Enabled: true, Part: "header"},
			{Enabled: true, Part: "body"},
		}, true},
	}
	for _, tt := range tests {
		t.Run(tt.name, func(t *testing.T) {
			if got := HasBodyRules(tt.rs); got != tt.want {
				t.Errorf("HasBodyRules(%+v) = %v, want %v", tt.rs, got, tt.want)
			}
		})
	}
}

func TestApplyBodyLiteral(t *testing.T) {
	body := []byte(`{"admin":false,"user":"bob"}`)
	rs := []Rule{{Enabled: true, Part: "body", Match: `"admin":false`, Replace: `"admin":true`}}
	got := ApplyBody(body, rs)
	want := `{"admin":true,"user":"bob"}`
	if string(got) != want {
		t.Errorf("ApplyBody = %q, want %q", got, want)
	}
}

func TestApplyBodyRegex(t *testing.T) {
	body := []byte(`user_id=12345&session=abc`)
	rs := []Rule{{Enabled: true, Part: "body", Match: `user_id=\d+`, Replace: "user_id=1", IsRegex: true}}
	got := ApplyBody(body, rs)
	want := `user_id=1&session=abc`
	if string(got) != want {
		t.Errorf("ApplyBody = %q, want %q", got, want)
	}
}

func TestApplyBodySkipsDisabledAndHeaderRules(t *testing.T) {
	body := []byte("hello world")
	rs := []Rule{
		{Enabled: false, Part: "body", Match: "hello", Replace: "bye"},
		{Enabled: true, Part: "header", Match: "world", Replace: "planet"},
	}
	got := ApplyBody(body, rs)
	if string(got) != "hello world" {
		t.Errorf("ApplyBody = %q, want unchanged %q", got, "hello world")
	}
}

func TestApplyBodyRespectsPositionOrder(t *testing.T) {
	body := []byte("aaa")
	rs := []Rule{
		{Enabled: true, Part: "body", Match: "a", Replace: "b", Position: 1},
		{Enabled: true, Part: "body", Match: "b", Replace: "c", Position: 0},
	}
	// Position 0 runs first: "aaa" -[b->c, no match]-> "aaa" -[a->b]-> "bbb"
	got := ApplyBody(body, rs)
	if string(got) != "bbb" {
		t.Errorf("ApplyBody = %q, want %q", got, "bbb")
	}
}

func TestApplyHeadersAddsRemovesHeader(t *testing.T) {
	h := http.Header{"Host": []string{"example.com"}}
	rs := []Rule{{Enabled: true, Part: "header", Match: "Host: example.com", Replace: "Host: example.com\r\nX-Injected: 1"}}
	got := ApplyHeaders(h, rs)
	if got.Get("X-Injected") != "1" {
		t.Errorf("expected X-Injected header to be added, got %+v", got)
	}
}

func TestApplyHeadersInvalidRegexLeavesUnchanged(t *testing.T) {
	h := http.Header{"Host": []string{"example.com"}}
	rs := []Rule{{Enabled: true, Part: "header", Match: "(unclosed", Replace: "x", IsRegex: true}}
	got := ApplyHeaders(h, rs)
	if got.Get("Host") != "example.com" {
		t.Errorf("expected headers unchanged on invalid regex, got %+v", got)
	}
}