package loop

import (
	"context"
	"io"
	"net/http"
	"net/http/httptest"
	"strings"
	"sync"
	"testing"

	"git.yeij.top/AskaEth/Cyrene_v2/internal/config"
	"git.yeij.top/AskaEth/Cyrene_v2/internal/runtime/agent"
	"git.yeij.top/AskaEth/Cyrene_v2/internal/runtime/model"
)

// anthropicToolRoundSSE is a native Anthropic stream that thinks, then emits a
// tool_use block with an empty text part — the exact shape that starved the old
// loop (which only looked for a JSON envelope in Content).
const anthropicToolRoundSSE = `data: {"type":"message_start","message":{"model":"m","usage":{"input_tokens":10}}}

data: {"type":"content_block_start","index":0,"content_block":{"type":"thinking","thinking":""}}

data: {"type":"content_block_delta","index":0,"delta":{"type":"thinking_delta","thinking":"checking the clock"}}

data: {"type":"content_block_stop","index":0}

data: {"type":"content_block_start","index":1,"content_block":{"type":"tool_use","id":"toolu_1","name":"datetime","input":{}}}

data: {"type":"content_block_delta","index":1,"delta":{"type":"input_json_delta","partial_json":"{\"timezone\":\"Asia/Shanghai\"}"}}

data: {"type":"content_block_stop","index":1}

data: {"type":"message_delta","delta":{"stop_reason":"tool_use"},"usage":{"output_tokens":20}}

data: {"type":"message_stop"}

`

// anthropicTextRoundSSE is the follow-up stream: a plain text answer after the
// tool result was fed back.
const anthropicTextRoundSSE = `data: {"type":"message_start","message":{"model":"m","usage":{"input_tokens":30}}}

data: {"type":"content_block_start","index":0,"content_block":{"type":"text","text":""}}

data: {"type":"content_block_delta","index":0,"delta":{"type":"text_delta","text":"现在是 10:34。"}}

data: {"type":"content_block_stop","index":0}

data: {"type":"message_delta","delta":{"stop_reason":"end_turn"},"usage":{"output_tokens":8}}

data: {"type":"message_stop"}

`

// TestRun_NativeToolCall_AnthropicAdapter_HTTP exercises the real loop path end
// to end through the real AnthropicChatAdapter against a stub /v1/messages
// server: round 1 streams a thinking + tool_use block with no text, the loop
// must execute it and re-ask, and round 2 must carry the assistant tool_use turn
// plus a correlated tool_result and return the model's text (not an empty reply).
func TestRun_NativeToolCall_AnthropicAdapter_HTTP(t *testing.T) {
	t.Parallel()
	var mu sync.Mutex
	round := 0
	var secondBody string
	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		body, _ := io.ReadAll(r.Body)
		mu.Lock()
		round++
		n := round
		if n == 2 {
			secondBody = string(body)
		}
		mu.Unlock()
		w.Header().Set("Content-Type", "text/event-stream")
		if n == 1 {
			_, _ = io.WriteString(w, anthropicToolRoundSSE)
			return
		}
		_, _ = io.WriteString(w, anthropicTextRoundSSE)
	}))
	t.Cleanup(srv.Close)

	ad := model.NewAnthropicChat(config.LLMConfig{AnthropicBaseURL: srv.URL, AnthropicModel: "m"})
	td := dispatcherWith(t, &mockTool{name: "datetime", result: map[string]any{"now": "2026-09-08 22:34:00"}})
	ag, err := agent.New("你是昔涟。", td, nil, agent.WithModel(ad, nil))
	if err != nil {
		t.Fatalf("agent.New: %v", err)
	}
	l := New(Options{Agent: ag, MaxRounds: 8, OnStream: func(model.StreamEvent) {}})

	res, err := l.Run(context.Background(), "sess", []model.Message{model.TextMessage(model.RoleUser, "瞅瞅当前系统时间是多少")})
	if err != nil {
		t.Fatalf("Run: %v", err)
	}
	if res.Text != "现在是 10:34。" {
		t.Fatalf("Text = %q, want the follow-up answer (empty means the native tool call was dropped)", res.Text)
	}
	if res.ToolCallsExecuted != 1 {
		t.Fatalf("ToolCallsExecuted = %d, want 1", res.ToolCallsExecuted)
	}
	if secondBody == "" {
		t.Fatal("adapter never made a second request (tool result was not fed back)")
	}
	for _, want := range []string{`"type":"tool_use"`, `"id":"toolu_1"`, `"type":"tool_result"`, `"tool_use_id":"toolu_1"`} {
		if !strings.Contains(secondBody, want) {
			t.Fatalf("second request missing %s:\n%s", want, secondBody)
		}
	}
}