package ctxmgr

import (
	"fmt"
	"strings"
	"testing"
)

func TestAssembleWindow_MaxTurnsBudget(t *testing.T) {
	// 构造 20 条消息
	var msgs []ChatMessageRecord
	for i := 1; i <= 20; i++ {
		role := "user"
		if i%2 == 0 {
			role = "assistant"
		}
		msgs = append(msgs, ChatMessageRecord{
			ID:      int64(i),
			Role:    role,
			Content: fmt.Sprintf("这是测试消息第 %d 条内容", i),
		})
	}

	cfg := WindowConfig{
		MaxTurns:    8, // 最多 8 条
		TokenBudget: 5000,
		ReserveTail: 500,
	}

	window, early, truncated := AssembleWindow(msgs, cfg)
	if !truncated {
		t.Fatalf("expected truncated to be true")
	}
	if len(window) != 8 {
		t.Errorf("expected 8 messages in window, got %d", len(window))
	}
	if len(early) != 12 {
		t.Errorf("expected 12 messages in early, got %d", len(early))
	}
	// 检查窗口中第一条是否是第 13 条
	if window[0].ID != 13 {
		t.Errorf("expected window start with ID 13, got %d", window[0].ID)
	}
	// 检查窗口最后一条是否是第 20 条
	if window[len(window)-1].ID != 20 {
		t.Errorf("expected window end with ID 20, got %d", window[len(window)-1].ID)
	}
}

func TestAssembleWindow_TokenBudgetLimit(t *testing.T) {
	// 构造 5 条消息，每条内容长度 350 字符
	var msgs []ChatMessageRecord
	for i := 1; i <= 5; i++ {
		msgs = append(msgs, ChatMessageRecord{
			ID:      int64(i),
			Role:    "user",
			Content: strings.Repeat("长文本七字内容", 50), // 7 * 50 = 350 字符
		})
	}

	cfg := WindowConfig{
		MaxTurns:    10,   // 条数未超限
		TokenBudget: 1000, // 预算 1000
		ReserveTail: 200,  // 净可用 800，最多容纳 2 条 (300*2=600 <= 800)
	}

	window, early, truncated := AssembleWindow(msgs, cfg)
	if !truncated {
		t.Fatalf("expected truncated to be true")
	}
	if len(window) != 2 {
		t.Errorf("expected 2 messages in window due to token budget, got %d", len(window))
	}
	if len(early) != 3 {
		t.Errorf("expected 3 early messages, got %d", len(early))
	}
}

func TestFormatNumberedDialogue(t *testing.T) {
	msgs := []ChatMessageRecord{
		{Role: "user", Content: "你好，请问你是谁？"},
		{Role: "assistant", Content: "我是水木东方研发协同参谋。"},
	}

	formatted := FormatNumberedDialogue(msgs, 5)
	expected := "[5] 用户: 你好，请问你是谁？\n[6] 助手: 我是水木东方研发协同参谋。\n"
	if formatted != expected {
		t.Errorf("expected formatted output:\n%s\ngot:\n%s", expected, formatted)
	}
}