package ai

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

func TestServiceNudgeSuccess(t *testing.T) {
	fb := &fakeBackend{out: `{"on_track": false, "message": "reading news, not the auth flow"}`}
	advisory, err := NewService(fb).Nudge(context.Background(), "fix auth", []string{"Firefox - Hacker News"})
	if err != nil {
		t.Fatalf("nudge: %v", err)
	}
	if advisory == "" {
		t.Fatal("expected non-empty advisory")
	}
	if !strings.Contains(fb.gotPrompt, "fix auth") {
		t.Fatalf("prompt should embed the commitment, got: %s", fb.gotPrompt)
	}
}

func TestServiceNudgeBackendError(t *testing.T) {
	fb := &fakeBackend{err: errors.New("boom")}
	if _, err := NewService(fb).Nudge(context.Background(), "fix auth", []string{"Firefox - Hacker News"}); err == nil {
		t.Fatal("want backend error")
	}
}

func TestParseNudge(t *testing.T) {
	tests := []struct {
		name    string
		in      string
		want    string
		wantErr error
	}{
		{"on track yields empty", `{"on_track": true, "message": ""}`, "", nil},
		{"concern returns message", `{"on_track": false, "message": "editing unrelated CSS, not the auth flow"}`, "editing unrelated CSS, not the auth flow", nil},
		{"concern is trimmed", `{"on_track": false, "message": "  drifted  "}`, "drifted", nil},
		{"concern without message degrades to silence", `{"on_track": false, "message": ""}`, "", nil},
		{"json embedded in prose", `sure thing: {"on_track": false, "message": "wrong project"} done`, "wrong project", nil},
		{"empty response", "   ", "", ErrEmptyResponse},
		{"no json", "no braces here", "", ErrNoJSON},
		{"malformed json", `{"on_track": false, "message":`, "", ErrInvalidNudge},
	}
	for _, tt := range tests {
		t.Run(tt.name, func(t *testing.T) {
			got, err := parseNudge(tt.in)
			if tt.wantErr != nil {
				if !errors.Is(err, tt.wantErr) {
					t.Fatalf("err = %v, want %v", err, tt.wantErr)
				}
				return
			}
			if err != nil {
				t.Fatalf("unexpected err: %v", err)
			}
			if got != tt.want {
				t.Fatalf("got %q, want %q", got, tt.want)
			}
		})
	}
}