package agent

import (
	"context"
	"path/filepath"
	"strings"
	"testing"
	"time"

	"github.com/crypto/byteclaw/internal/llm"
	"github.com/crypto/byteclaw/internal/store"
	"github.com/crypto/byteclaw/internal/tools"
)

// scripted provider returns queued responses and records requests.
type scripted struct {
	resps []llm.Response
	reqs  []llm.Request
}

func (s *scripted) Chat(_ context.Context, req llm.Request, d llm.DeltaFunc) (llm.Response, error) {
	s.reqs = append(s.reqs, req)
	r := s.resps[0]
	s.resps = s.resps[1:]
	if d != nil && r.Content != "" {
		d(r.Content)
	}
	return r, nil
}

func newStore(t *testing.T) *store.Store {
	s, err := store.Open(filepath.Join(t.TempDir(), "a.db"))
	if err != nil {
		t.Fatal(err)
	}
	t.Cleanup(func() { s.Close() })
	return s
}

func TestToolLoop(t *testing.T) {
	st := newStore(t)
	ss, _ := st.CreateSession(context.Background(), "")
	p := &scripted{resps: []llm.Response{
		{ToolCalls: []llm.ToolCall{{ID: "c1", Name: "time_now", Arguments: `{"timezone":"UTC"}`}}},
		{Content: "It is noon."},
	}}
	fixed := time.Date(2026, 5, 5, 12, 0, 0, 0, time.UTC)
	a := &Agent{LLM: p, Store: st, Tools: tools.NewRegistry(tools.TimeNow{Now: func() time.Time { return fixed }}), SystemPrompt: "sys", MaxIterations: 4}
	var events []Event
	out, err := a.Run(context.Background(), ss.ID, "what time?", func(e Event) { events = append(events, e) })
	if err != nil || out != "It is noon." {
		t.Fatalf("%q %v", out, err)
	}
	second := p.reqs[1].Messages
	if second[0].Role != llm.RoleSystem || second[len(second)-1].Role != llm.RoleTool || !strings.HasPrefix(second[len(second)-1].Content, "2026-05-05T12:00:00") {
		t.Fatalf("bad second request: %+v", second)
	}
	types := []string{}
	for _, e := range events {
		types = append(types, e.Type)
	}
	if strings.Join(types, ",") != "tool_call,tool_result,delta" {
		t.Fatalf("events %v", types)
	}
	msgs, _ := st.Messages(context.Background(), ss.ID, 0)
	if len(msgs) != 4 {
		t.Fatalf("stored %d msgs", len(msgs))
	}
}

func TestMaxIterations(t *testing.T) {
	st := newStore(t)
	ss, _ := st.CreateSession(context.Background(), "")
	call := llm.Response{ToolCalls: []llm.ToolCall{{ID: "c", Name: "time_now", Arguments: "{}"}}}
	a := &Agent{LLM: &scripted{resps: []llm.Response{call, call}}, Store: st, Tools: tools.NewRegistry(tools.TimeNow{}), MaxIterations: 2}
	if _, err := a.Run(context.Background(), ss.ID, "loop", nil); err == nil {
		t.Fatal("expected iteration error")
	}
}

func TestHistoryDropsOrphanToolMessages(t *testing.T) {
	st := newStore(t)
	ctx := context.Background()
	ss, _ := st.CreateSession(ctx, "")
	st.AppendMessage(ctx, ss.ID, llm.Message{Role: llm.RoleAssistant, ToolCalls: []llm.ToolCall{{ID: "x", Name: "t"}}})
	st.AppendMessage(ctx, ss.ID, llm.Message{Role: llm.RoleTool, ToolCallID: "x", Content: "r"})
	st.AppendMessage(ctx, ss.ID, llm.Message{Role: llm.RoleAssistant, Content: "ok"})
	a := &Agent{Store: st, HistoryLimit: 2}
	h, _ := a.history(ctx, ss.ID)
	if len(h) != 1 || h[0].Content != "ok" {
		t.Fatalf("%+v", h)
	}
}