package ai

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

func TestParseVerdictOnTask(t *testing.T) {
	v, err := parseVerdict(`{"on_task": true, "reason": ""}`)
	if err != nil {
		t.Fatalf("parse: %v", err)
	}
	if !v.OnTask {
		t.Fatalf("expected on-task, got %+v", v)
	}
}

func TestParseVerdictDriftingChatty(t *testing.T) {
	v, err := parseVerdict("Sure! here is the call:\n{\"on_task\": false, \"reason\": \"Reddit is unrelated\"}\nhope that helps")
	if err != nil {
		t.Fatalf("parse: %v", err)
	}
	if v.OnTask || v.Reason != "Reddit is unrelated" {
		t.Fatalf("bad verdict: %+v", v)
	}
}

func TestParseVerdictDriftingNeedsReason(t *testing.T) {
	if _, err := parseVerdict(`{"on_task": false}`); !errors.Is(err, ErrInvalidVerdict) {
		t.Fatalf("want ErrInvalidVerdict for reasonless drift, got %v", err)
	}
}

func TestParseVerdictEmpty(t *testing.T) {
	if _, err := parseVerdict("   "); !errors.Is(err, ErrEmptyResponse) {
		t.Fatalf("want ErrEmptyResponse, got %v", err)
	}
}

func TestParseVerdictNoJSON(t *testing.T) {
	if _, err := parseVerdict("I cannot help"); !errors.Is(err, ErrNoJSON) {
		t.Fatalf("want ErrNoJSON, got %v", err)
	}
}

func TestServiceJudgeDrift(t *testing.T) {
	fb := &fakeBackend{out: `{"on_task": false, "reason": "YouTube is off-task"}`}
	v, err := NewService(fb).JudgeDrift(context.Background(), "write the report", "firefox", "YouTube")
	if err != nil {
		t.Fatalf("judge: %v", err)
	}
	if v.OnTask || v.Reason == "" {
		t.Fatalf("bad verdict: %+v", v)
	}
	if !strings.Contains(fb.gotPrompt, "write the report") || !strings.Contains(fb.gotPrompt, "YouTube") {
		t.Fatalf("prompt should embed commitment and window: %s", fb.gotPrompt)
	}
}

func TestServiceJudgeDriftBackendError(t *testing.T) {
	fb := &fakeBackend{err: errors.New("boom")}
	if _, err := NewService(fb).JudgeDrift(context.Background(), "x", "c", "t"); err == nil {
		t.Fatal("want backend error")
	}
}