package documents

import (
	"context"
	"encoding/json"
	"errors"
	"os"
	"path/filepath"
	"strings"
	"testing"

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

// 这些测试钉住摄取层的落地事实（design/24 §4.3/§4.4）：**只抽一次**（第二次读
// sidecar，原文件被删也照样出正文）、失败可见（unreadable + 诚实原因，且失败也
// 只抽一次）、名字形态非法绝不碰文件系统、抽取器版本变化让缓存失效。

// testLayout 是一份隔离的临时目录布局：数据目录 + S1 的上传目录。
type testLayout struct {
	dataDir string
	uploads string
}

func newTestLayout(t *testing.T) testLayout {
	t.Helper()
	data := t.TempDir()
	uploads := filepath.Join(data, "uploads", "documents")
	if err := os.MkdirAll(uploads, 0o700); err != nil {
		t.Fatalf("mkdir uploads: %v", err)
	}
	return testLayout{dataDir: data, uploads: uploads}
}

// writeUpload 把一份文档放进上传目录，返回它的存储名。
func (l testLayout) writeUpload(t *testing.T, name string, data []byte) string {
	t.Helper()
	if err := os.WriteFile(filepath.Join(l.uploads, name), data, 0o600); err != nil {
		t.Fatalf("write upload: %v", err)
	}
	return name
}

// sidecarPath 是某份文档的 sidecar 路径。
func (l testLayout) sidecarPath(name string) string {
	return filepath.Join(l.dataDir, sidecarDirName, name+sidecarSuffix)
}

// resolveOne 用给定解析器解析一份文档消息，返回结论与正文（测试专用的窄入口）。
func resolveOne(t *testing.T, r *Resolver, name string) (history.DocumentRef, string) {
	t.Helper()
	msg := model.DocumentMessage(model.RoleUser, "", model.Document{Name: name, MIME: "text/plain", Size: 0})
	refs, bodies, err := r.Resolve(context.Background(), msg)
	if err != nil {
		t.Fatalf("Resolve: %v", err)
	}
	return refs[name], bodies[name]
}

// TestResolver_ExtractsOnceAndThenReadsSidecar 钉住「只抽一次」（design/24 §4.3）：
// 首次解析写 sidecar，之后**原文件被删**也能从 sidecar 出正文，且 sidecar 不被
// 重写（mtime 不变 —— 「后续回合不再碰原文件」在文件系统上可观测）。
func TestResolver_ExtractsOnceAndThenReadsSidecar(t *testing.T) {
	t.Parallel()
	layout := newTestLayout(t)
	body := "报告正文：三个要点。\n"
	name := layout.writeUpload(t, txtName, []byte(body))
	r := NewResolver(Config{DataDir: layout.dataDir, UploadsDir: layout.uploads})

	ref, got := resolveOne(t, r, name)
	if ref.Status != history.DocumentStatusExtracted || got != body {
		t.Fatalf("首次解析 = (%+v, %q), want extracted + 原文", ref, got)
	}
	first, err := os.Stat(layout.sidecarPath(name))
	if err != nil {
		t.Fatalf("sidecar 未写出: %v", err)
	}

	if err := os.Remove(filepath.Join(layout.uploads, name)); err != nil {
		t.Fatalf("删除原文件: %v", err)
	}
	ref2, got2 := resolveOne(t, r, name)
	if ref2.Status != history.DocumentStatusExtracted || got2 != body {
		t.Fatalf("第二次解析 = (%+v, %q), want 从 sidecar 得到同一正文", ref2, got2)
	}
	second, err := os.Stat(layout.sidecarPath(name))
	if err != nil {
		t.Fatalf("sidecar 消失: %v", err)
	}
	if !second.ModTime().Equal(first.ModTime()) {
		t.Fatalf("sidecar 被重写：mtime %v → %v（「只写一次」被破坏）", first.ModTime(), second.ModTime())
	}
}

// TestResolver_KeepsFullBodyAndRecordsSafetyTruncationInSidecar 钉住 sidecar 的
// 存全文语义（切片 T1 §7.2 第 1 条）与安全上限的如实记账：
//
//   - 正文远超旧的 64K 注入预算、但未撞上安全上限 ⇒ 整份存下，truncated=false，
//     因此 document-read 按清单游标续读能真的读到预算之外的正文；
//   - 撞上安全上限（MaxSidecarBytes）⇒ truncated=true 且字符数随 sidecar 往返。
func TestResolver_KeepsFullBodyAndRecordsSafetyTruncationInSidecar(t *testing.T) {
	t.Parallel()
	layout := newTestLayout(t)
	name := layout.writeUpload(t, txtName, []byte(strings.Repeat("宽", 100*1024)))
	r := NewResolver(Config{DataDir: layout.dataDir, UploadsDir: layout.uploads})

	ref, body := resolveOne(t, r, name)
	if ref.Truncated || ref.Chars != 100*1024 {
		t.Fatalf("首次解析 = %+v, want 全文（%d 字符、未截断）", ref, 100*1024)
	}
	if err := os.Remove(filepath.Join(layout.uploads, name)); err != nil {
		t.Fatalf("删除原文件: %v", err)
	}
	ref2, body2 := resolveOne(t, r, name)
	if ref2.Truncated || ref2.Chars != 100*1024 || body2 != body {
		t.Fatalf("sidecar 命中 = %+v, want 从 sidecar 读回同一份全文", ref2)
	}

	capped := layout.writeUpload(t, "0123456789abcdef0123456789abcdee.txt", []byte(strings.Repeat("宽", MaxSidecarBytes)))
	ref3, body3 := resolveOne(t, r, capped)
	if !ref3.Truncated {
		t.Fatalf("撞上安全上限的文档 = %+v, want truncated=true", ref3)
	}
	if ref3.Chars != len([]rune(body3)) || len(body3) > MaxSidecarBytes {
		t.Fatalf("上限命中：Chars=%d / 正文字节=%d，want 一致且不超过 %d", ref3.Chars, len(body3), MaxSidecarBytes)
	}
}

// TestResolver_UnreadableIsHonestAndCached 钉住失败可见（design/24 §4.4）：图片型/
// 无文本层 PDF 得到 unreadable + **诚实原因**（必须点明「需要 OCR」），清单/回传
// 状态有来源；失败同样只抽一次。
func TestResolver_UnreadableIsHonestAndCached(t *testing.T) {
	t.Parallel()
	layout := newTestLayout(t)
	name := layout.writeUpload(t, pdfName, buildPDF(t, pdfFixture{Contents: []string{imageContent}}))
	r := NewResolver(Config{DataDir: layout.dataDir, UploadsDir: layout.uploads})

	ref, body := resolveOne(t, r, name)
	if ref.Status != history.DocumentStatusUnreadable {
		t.Fatalf("Status = %q, want %q", ref.Status, history.DocumentStatusUnreadable)
	}
	if body != reasonPDFNoTextLayer {
		t.Fatalf("body = %q, want %q", body, reasonPDFNoTextLayer)
	}
	if !strings.Contains(body, "OCR") {
		t.Fatalf("原因文案 %q 没点明需要 OCR（用户要知道这份 PDF 得先转文字）", body)
	}
	if _, err := os.Stat(layout.sidecarPath(name)); err != nil {
		t.Fatalf("失败的抽取也应留下 sidecar（只抽一次同样适用于失败）: %v", err)
	}
	if err := os.Remove(filepath.Join(layout.uploads, name)); err != nil {
		t.Fatalf("删除原文件: %v", err)
	}
	if _, body2 := resolveOne(t, r, name); body2 != reasonPDFNoTextLayer {
		t.Fatalf("第二次 body = %q, want 从 sidecar 读回同一原因", body2)
	}
}

// TestResolver_PDFPagesAndKindReachTheSidecar 钉住切片 B1 的 sidecar 元数据：
// PDF 的抽取结论带 `kind=pdf` 与**页数** —— 两者随 sidecar 落盘、可被读侧取回，
// 因此「这份 PDF 一共产出多少页」在缓存里是可查的事实（不是只留在日志里）。
func TestResolver_PDFPagesAndKindReachTheSidecar(t *testing.T) {
	t.Parallel()
	layout := newTestLayout(t)
	name := layout.writeUpload(t, pdfName, buildPDF(t, pdfFixture{Contents: []string{
		textContent("first page"),
		textContent("second page"),
		textContent("third page"),
	}}))
	r := NewResolver(Config{DataDir: layout.dataDir, UploadsDir: layout.uploads})

	ref, body := resolveOne(t, r, name)
	if ref.Status != history.DocumentStatusExtracted || !strings.Contains(body, "third page") {
		t.Fatalf("解析 = (%+v, %q), want extracted 且含第三页正文", ref, body)
	}
	side, err := ReadSidecar(layout.dataDir, name)
	if err != nil {
		t.Fatalf("ReadSidecar: %v", err)
	}
	if side.Kind != kindPDF || side.Pages != 3 {
		t.Fatalf("sidecar = (kind=%q, pages=%d), want (%q,3)", side.Kind, side.Pages, kindPDF)
	}
	raw, err := os.ReadFile(layout.sidecarPath(name))
	if err != nil {
		t.Fatalf("读 sidecar: %v", err)
	}
	header, _, ok := strings.Cut(string(raw), sidecarHeaderEnd)
	if !ok {
		t.Fatalf("sidecar 缺少元数据行: %q", raw)
	}
	var meta sidecarMeta
	if err := json.Unmarshal([]byte(header), &meta); err != nil {
		t.Fatalf("元数据行解码失败: %v (%q)", err, header)
	}
	if meta.Kind != kindPDF || meta.Pages != 3 || meta.Version != ExtractorVersion {
		t.Fatalf("落盘元数据 = (kind=%q, pages=%d, v=%q), want (%q,3,%q)",
			meta.Kind, meta.Pages, meta.Version, kindPDF, ExtractorVersion)
	}
}

// TestResolver_MissingFileIsUnreadable 钉住「文件不存在」不是 error、也不是
// 静默：它是一条 unreadable 结论 + 诚实原因（回合照常继续）。
func TestResolver_MissingFileIsUnreadable(t *testing.T) {
	t.Parallel()
	layout := newTestLayout(t)
	r := NewResolver(Config{DataDir: layout.dataDir, UploadsDir: layout.uploads})

	ref, body := resolveOne(t, r, txtName)
	if ref.Status != history.DocumentStatusUnreadable || body != reasonMissing {
		t.Fatalf("解析不存在的文档 = (%+v, %q), want unreadable + %q", ref, body, reasonMissing)
	}
	if ref.Name != txtName {
		t.Fatalf("Name = %q, want 部件里的存储名（身份来自部件）", ref.Name)
	}
}

// TestResolver_RejectsIllegalStorageName 钉住防御性的路径安全：形态非法的名字
// 绝不参与读盘或 sidecar 路径，只得到 unreadable + 诚实原因。
func TestResolver_RejectsIllegalStorageName(t *testing.T) {
	t.Parallel()
	layout := newTestLayout(t)
	r := NewResolver(Config{DataDir: layout.dataDir, UploadsDir: layout.uploads})

	for _, name := range []string{"../secret.txt", "..", "a.txt", "0123456789abcdef0123456789abcde.txt", "0123456789abcdef0123456789abcdef./x.txt"} {
		ref, body := resolveOne(t, r, name)
		if ref.Status != history.DocumentStatusUnreadable || body != reasonNameInvalid {
			t.Fatalf("解析 %q = (%+v, %q), want unreadable + %q", name, ref, body, reasonNameInvalid)
		}
	}
	entries, err := os.ReadDir(filepath.Join(layout.dataDir, sidecarDirName))
	if err != nil && !errors.Is(err, os.ErrNotExist) {
		t.Fatalf("read extracted dir: %v", err)
	}
	if len(entries) != 0 {
		t.Fatalf("非法名字竟然写出了 %d 个 sidecar", len(entries))
	}
}

// TestSidecar_SaveRejectsIllegalName 钉住 sidecar 写入的防御层：形态非法的名字
// 绝不落盘，也绝不把路径带出 sidecar 目录。
func TestSidecar_SaveRejectsIllegalName(t *testing.T) {
	t.Parallel()
	dir := t.TempDir()
	store := newSidecarStore(dir, sourcedLog(nil))
	err := store.save("../escape.txt", cachedExtract{Status: history.DocumentStatusExtracted}, 1)
	if !errors.Is(err, ErrInvalidName) {
		t.Fatalf("save(非法名) = %v, want ErrInvalidName", err)
	}
	entries, readErr := os.ReadDir(dir)
	if readErr != nil {
		t.Fatalf("read dir: %v", readErr)
	}
	if len(entries) != 0 {
		t.Fatalf("非法名字竟然落盘了 %d 个文件", len(entries))
	}
}

// TestSidecar_StaleVersionIsReextracted 钉住「抽取器版本」的用处（design/24
// §4.3）：旧版本的 sidecar 判为失效并重抽一次，新版结论落到盘上。
func TestSidecar_StaleVersionIsReextracted(t *testing.T) {
	t.Parallel()
	layout := newTestLayout(t)
	body := "正文\n"
	name := layout.writeUpload(t, txtName, []byte(body))
	if err := os.MkdirAll(filepath.Join(layout.dataDir, sidecarDirName), sidecarDirMode); err != nil {
		t.Fatalf("mkdir extracted: %v", err)
	}
	header, err := json.Marshal(sidecarMeta{Version: "documents/v0", Status: history.DocumentStatusExtracted, Chars: 2})
	if err != nil {
		t.Fatalf("marshal meta: %v", err)
	}
	if err := os.WriteFile(layout.sidecarPath(name), append(header, '\n'), 0o600); err != nil {
		t.Fatalf("write stale sidecar: %v", err)
	}

	r := NewResolver(Config{DataDir: layout.dataDir, UploadsDir: layout.uploads})
	ref, got := resolveOne(t, r, name)
	if ref.Status != history.DocumentStatusExtracted || got != body {
		t.Fatalf("解析 = (%+v, %q), want 重抽得到 %q", ref, got, body)
	}
	raw, err := os.ReadFile(layout.sidecarPath(name))
	if err != nil {
		t.Fatalf("read sidecar: %v", err)
	}
	if !strings.Contains(string(raw), ExtractorVersion) {
		t.Fatalf("sidecar 仍是旧版本: %q", string(raw))
	}
}

// TestSidecar_CorruptIsReextracted 钉住「缓存坏了就重抽」：损坏的 sidecar 绝不
// 让解析失败，也绝不把畸形内容当正文注入。
func TestSidecar_CorruptIsReextracted(t *testing.T) {
	t.Parallel()
	layout := newTestLayout(t)
	body := "好内容\n"
	name := layout.writeUpload(t, txtName, []byte(body))
	if err := os.MkdirAll(filepath.Join(layout.dataDir, sidecarDirName), sidecarDirMode); err != nil {
		t.Fatalf("mkdir extracted: %v", err)
	}
	if err := os.WriteFile(layout.sidecarPath(name), []byte("not-json\n垃圾"), 0o600); err != nil {
		t.Fatalf("write corrupt sidecar: %v", err)
	}

	r := NewResolver(Config{DataDir: layout.dataDir, UploadsDir: layout.uploads})
	ref, got := resolveOne(t, r, name)
	if ref.Status != history.DocumentStatusExtracted || got != body {
		t.Fatalf("解析 = (%+v, %q), want 重抽得到 %q", ref, got, body)
	}
}

// TestResolver_CanceledContextReturnsError 钉住契约里的 error 分支：单份文档的
// 失败是 unreadable 结论，而**整条消息解析不了**（回合已取消）才是 error，由
// 循环降级为诚实兜底。
func TestResolver_CanceledContextReturnsError(t *testing.T) {
	t.Parallel()
	layout := newTestLayout(t)
	name := layout.writeUpload(t, txtName, []byte("正文"))
	r := NewResolver(Config{DataDir: layout.dataDir, UploadsDir: layout.uploads})

	ctx, cancel := context.WithCancel(context.Background())
	cancel()
	msg := model.DocumentMessage(model.RoleUser, "", model.Document{Name: name, MIME: "text/plain"})
	if _, _, err := r.Resolve(ctx, msg); !errors.Is(err, context.Canceled) {
		t.Fatalf("Resolve(已取消的 ctx) = %v, want context.Canceled", err)
	}
}

// TestResolver_NoDocumentsIsNoWork 钉住短路：没有文档部件时不做任何工作，也
// 不产生结论（使没有附件的回合与接线前逐字节一致）。
func TestResolver_NoDocumentsIsNoWork(t *testing.T) {
	t.Parallel()
	r := NewResolver(Config{})
	refs, bodies, err := r.Resolve(context.Background(), model.TextMessage(model.RoleUser, "没有附件"))
	if err != nil || refs != nil || bodies != nil {
		t.Fatalf("Resolve(无文档) = (%v, %v, %v), want (nil, nil, nil)", refs, bodies, err)
	}
}

// TestResolver_UploadsDirMissingIsUnreadable 钉住配置缺失时的诚实：上传目录
// 没接上时每份文档都是 unreadable（而不是假装读到、也不是 error）。
func TestResolver_UploadsDirMissingIsUnreadable(t *testing.T) {
	t.Parallel()
	layout := newTestLayout(t)
	r := NewResolver(Config{DataDir: layout.dataDir})
	ref, body := resolveOne(t, r, txtName)
	if ref.Status != history.DocumentStatusUnreadable || body != reasonNoUploadDir {
		t.Fatalf("解析 = (%+v, %q), want unreadable + %q", ref, body, reasonNoUploadDir)
	}
}

// recordingAdapter 是集成测试用的最小模型适配器：记录喂给模型的请求并回一句
// 文本，使测试能断言「模型实际看到了什么」。
type recordingAdapter struct{ reqs []model.Request }

func (a *recordingAdapter) Name() string { return "recording" }

func (a *recordingAdapter) Chat(_ context.Context, req model.Request, _ model.Options) (model.Response, error) {
	a.reqs = append(a.reqs, req)
	return model.Response{Model: "stub", Content: "好"}, nil
}

func (a *recordingAdapter) ChatStream(ctx context.Context, req model.Request, _ func(model.StreamEvent)) (model.Response, error) {
	return a.Chat(ctx, req, model.Options{})
}

// TestResolver_EndToEndWithLoop 是本切片唯一的跨包集成：真实解析器 + 真实循环，
// 证明「上传目录里的文档 → sidecar → 装配期注入 → 模型可见正文」这条链闭合，
// 且文档部件在模型可见上下文里一个不剩（S2 的编码器对文档 fail-loud）。
func TestResolver_EndToEndWithLoop(t *testing.T) {
	t.Parallel()
	layout := newTestLayout(t)
	body := "季度报告：营收增长 12%。\n"
	name := layout.writeUpload(t, txtName, []byte(body))
	r := NewResolver(Config{DataDir: layout.dataDir, UploadsDir: layout.uploads})

	ad := &recordingAdapter{}
	ag, err := agent.New("你是助手。", nil, nil, agent.WithModel(ad, nil))
	if err != nil {
		t.Fatalf("agent.New: %v", err)
	}
	l := loop.New(loop.Options{Agent: ag, DocumentResolver: r, MaxRounds: 1})
	msg := model.DocumentMessage(model.RoleUser, "看看附件", model.Document{Name: name, MIME: "text/plain", Size: int64(len(body))})
	res, err := l.Run(context.Background(), "sess-doc-e2e", []model.Message{msg})
	if err != nil {
		t.Fatalf("Run: %v", err)
	}
	if len(ad.reqs) == 0 {
		t.Fatal("没有记录到模型请求")
	}
	injected := false
	for _, m := range ad.reqs[0].Messages {
		for _, part := range m.Content {
			if part.Type == model.ContentTypeDocument {
				t.Fatalf("文档部件抵达了模型: %+v", m)
			}
			if part.Type == model.ContentTypeText && strings.Contains(part.Text, "营收增长 12%") {
				injected = true
			}
		}
	}
	if !injected {
		t.Fatal("抽取正文没有注入模型可见上下文")
	}
	if len(res.Documents) != 1 || res.Documents[0].Status != history.DocumentStatusExtracted {
		t.Fatalf("Result.Documents = %+v, want 一条 extracted", res.Documents)
	}
	if _, err := os.Stat(layout.sidecarPath(name)); err != nil {
		t.Fatalf("sidecar 未写出: %v", err)
	}
}