package session

import (
	"os"
	"path/filepath"
	"strings"
	"testing"

	"agent-native/runtime/llm"
)

func TestClearOldToolResultsKeepsLastFive(t *testing.T) {
	var msgs []llm.Message
	for i := 0; i < 8; i++ {
		id := string(rune('a' + i))
		msgs = append(msgs,
			llm.Message{Role: llm.RoleAssistant, ToolCalls: []llm.ToolCall{{ID: id, Name: "read_file"}}},
			llm.Message{Role: llm.RoleTool, Name: "read_file", ToolCallID: id, Content: "正文-" + id},
		)
	}
	out := ClearOldToolResults(msgs, 5)
	if len(out) != len(msgs) {
		t.Fatalf("len %d, want %d", len(out), len(msgs))
	}
	cleared := 0
	for i, m := range out {
		if m.Role != llm.RoleTool {
			if m.Role != msgs[i].Role || len(m.ToolCalls) != len(msgs[i].ToolCalls) {
				t.Fatalf("pairing changed at %d", i)
			}
			continue
		}
		if m.ToolCallID != msgs[i].ToolCallID {
			t.Fatalf("tool id changed at %d", i)
		}
		if strings.Contains(m.Content, "旧工具结果已清理") {
			cleared++
			if !strings.Contains(m.Content, m.ToolCallID) {
				t.Fatalf("placeholder missing call id: %s", m.Content)
			}
		} else if m.Content != msgs[i].Content {
			t.Fatalf("recent result changed: %s", m.Content)
		}
	}
	if cleared != 3 {
		t.Fatalf("cleared %d, want 3", cleared)
	}
	for _, m := range out[len(out)-10:] {
		if m.Role == llm.RoleTool && strings.Contains(m.Content, "旧工具结果已清理") {
			t.Fatalf("last five were cleared: %s", m.ToolCallID)
		}
	}
}

func TestNeedsClearUsesConservativeWindow(t *testing.T) {
	if NeedsClear(10, 0, 0, 0) {
		t.Fatal("small estimate must fit the default window")
	}
	if !NeedsClear(DefaultContextWindow, 0, DefaultOutputReserve, DefaultContextBuffer) {
		t.Fatal("estimate at the default window must clear")
	}
}

// ---- N2 WP1：旧工具结果落盘（路径占位）----

func spillFixture() []llm.Message {
	msgs := []llm.Message{{Role: llm.RoleUser, Content: "u"}}
	for i := 0; i < 7; i++ {
		id := "call-" + string(rune('a'+i))
		msgs = append(msgs,
			llm.Message{Role: llm.RoleAssistant, ToolCalls: []llm.ToolCall{{ID: id, Name: "read", Arguments: "{}"}}},
			llm.Message{Role: llm.RoleTool, ToolCallID: id, Name: "read", Content: "完整结果内容-" + id})
	}
	return msgs
}

func TestClearOldToolResultsSpillsToDisk(t *testing.T) {
	dir := t.TempDir()
	out := ClearOldToolResultsTo(spillFixture(), 5, dir)
	if len(out) != len(spillFixture()) {
		t.Fatal("消息条数不得变")
	}
	// 最旧两条被落盘，占位带路径。
	for i, id := range []string{"call-a", "call-b"} {
		path := filepath.Join(dir, id+".txt")
		b, err := os.ReadFile(path)
		if err != nil {
			t.Fatalf("落盘文件缺失：%v", err)
		}
		if string(b) != "完整结果内容-"+id {
			t.Fatalf("落盘内容不符：%q", b)
		}
		placeholder := out[2+i*2].Content
		if !strings.Contains(placeholder, path) {
			t.Fatalf("占位未带路径：%q", placeholder)
		}
	}
	// 保留的最近 5 条正文不动。
	if out[len(out)-1].Content != "完整结果内容-call-g" {
		t.Fatalf("最近结果被误改：%q", out[len(out)-1].Content)
	}
}

func TestClearOldToolResultsEmptyDirKeepsLegacyPlaceholder(t *testing.T) {
	out := ClearOldToolResultsTo(spillFixture(), 5, "")
	legacy := ClearOldToolResults(spillFixture(), 5)
	for i := range out {
		if out[i].Content != legacy[i].Content {
			t.Fatalf("空 dir 应与旧行为逐字节一致：msg %d", i)
		}
	}
}

func TestClearOldToolResultsSpillFailureFallsBack(t *testing.T) {
	// 不可写目录：占位回落为转录指针，不阻断。
	blocked := filepath.Join(t.TempDir(), "file")
	if err := os.WriteFile(blocked, []byte("x"), 0o644); err != nil {
		t.Fatal(err)
	}
	out := ClearOldToolResultsTo(spillFixture(), 5, filepath.Join(blocked, "sub"))
	if !strings.Contains(out[2].Content, "会话记录中的调用 call-a") {
		t.Fatalf("写盘失败应回落转录指针：%q", out[2].Content)
	}
}

func TestSpillResultSanitizesCallID(t *testing.T) {
	dir := t.TempDir()
	path, ok := spillResult(dir, "call/../evil\x00id", "x")
	if !ok {
		t.Fatal("spill 失败")
	}
	base := filepath.Base(path)
	if strings.Contains(base, "/") || strings.ContainsRune(base, 0) || filepath.Dir(path) != dir {
		t.Fatalf("文件名未消毒或越出目录：%q", path)
	}
}