package ai

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

func TestProposeParsesProposal(t *testing.T) {
	svc := NewService(&fakeBackend{out: `{"next_action":"call mum","rationale":"people goal"}`})
	p, err := svc.Propose(context.Background(), "off-screen brief")
	if err != nil {
		t.Fatalf("Propose: %v", err)
	}
	if p.NextAction != "call mum" || p.Rationale != "people goal" {
		t.Fatalf("proposal = %+v", p)
	}
}

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

func TestProposeUnparseable(t *testing.T) {
	fb := &fakeBackend{out: "I cannot help."}
	if _, err := NewService(fb).Propose(context.Background(), "brief"); !errors.Is(err, ErrNoJSON) {
		t.Fatalf("want ErrNoJSON, got %v", err)
	}
}

func TestProposePromptIncludesBrief(t *testing.T) {
	fb := &fakeBackend{out: `{"next_action":"a","rationale":"b"}`}
	if _, err := NewService(fb).Propose(context.Background(), "water the tomato plants"); err != nil {
		t.Fatalf("Propose: %v", err)
	}
	if !strings.Contains(fb.gotPrompt, "water the tomato plants") {
		t.Fatalf("prompt should embed the brief, got: %s", fb.gotPrompt)
	}
}

func TestProposePromptHasFollowUpRule(t *testing.T) {
	p := buildProposePrompt("brief")
	if !strings.Contains(p, "do not simply repeat") {
		t.Fatalf("prompt missing follow-up rule:\n%s", p)
	}
}