package handler

import (
	"fmt"
	"net/http"
	"net/url"
	"os"
	"path/filepath"
	"strconv"
	"strings"
	"time"

	"bj_power_mes/common/httpx"
	"bj_power_mes/ent"
	"bj_power_mes/internal/logic"
	"bj_power_mes/internal/svc"

	"github.com/zeromicro/go-zero/rest/pathvar"
)

// ---------- 附件（统一存储方案） ----------
//
// 落盘：<Upload.Dir>/年/月/日/<文件类型大写枚举>/<uuid>.<ext>
// 库内：filePath 只存相对路径；下载/预览按 id 提供，避免中文与多级路径问题。

// attachmentRow 附件返回视图（前端友好：附可直接预览/下载的 URL）。
type attachmentRow struct {
	ID         int    `json:"id"`
	BizType    string `json:"bizType"`
	BizID      string `json:"bizId"`
	FileType   string `json:"fileType"`
	FileName   string `json:"fileName"`
	FilePath   string `json:"filePath"`
	FileSize   int    `json:"fileSize"`
	FileExt    string `json:"fileExt"`
	MimeType   string `json:"mimeType"`
	Uploader   string `json:"uploader"`
	Archived   bool   `json:"archived"`
	Deleted    bool   `json:"deleted"`
	DeletedBy  string `json:"deletedBy"`
	CreatedAt  int64  `json:"createdAt"`
	URL        string `json:"url"`
	PreviewURL string `json:"previewUrl"`
}

func toAttachmentRow(a *ent.Attachment) *attachmentRow {
	// 预览走公开直链（文件名不可枚举：UUID + 日期目录），<img>/<iframe> 无法携带 JWT；
	// 下载走带鉴权的 id 路由，由服务端给出 RFC5987 中文文件名与 Content-Disposition。
	return &attachmentRow{
		ID: a.ID, BizType: a.BizType, BizID: a.BizId, FileType: a.FileType,
		FileName: a.FileName, FilePath: a.FilePath, FileSize: a.FileSize,
		FileExt: a.FileExt, MimeType: a.MimeType, Uploader: a.Uploader,
		Archived: a.Archived, Deleted: a.Deleted, DeletedBy: a.DeletedBy,
		CreatedAt:  a.CreatedAt.Unix(),
		URL:        "/api/v1/attachment/file/" + strconv.Itoa(a.ID) + "?dl=1",
		PreviewURL: previewURL(a.FilePath),
	}
}

// previewURL 相对路径 → 公开免鉴权直链（复用 /files 路由，天然支持多级目录）。
func previewURL(relPath string) string {
	if relPath == "" {
		return ""
	}
	return fileURL(relPath)
}

// AttachmentUploadHandler POST /attachment/upload
// multipart 字段：bizType(必填)、bizId(必填)、file(必填)、fileType(可选，大写枚举)
// 流式落盘 + MD5 秒传（同业务对象同 MD5 直接返回既有记录，不重复存文件）。
func AttachmentUploadHandler(svcCtx *svc.ServiceContext) http.HandlerFunc {
	return func(w http.ResponseWriter, r *http.Request) {
		if err := r.ParseMultipartForm(4 << 20); err != nil && err != http.ErrNotMultipart {
			httpx.BadRequest(w, "表单解析失败："+err.Error())
			return
		}
		bizType := strings.TrimSpace(r.FormValue("bizType"))
		bizId := strings.TrimSpace(r.FormValue("bizId"))
		if bizType == "" || bizId == "" {
			httpx.BadRequest(w, "bizType 与 bizId 必填")
			return
		}
		fileType := strings.ToUpper(strings.TrimSpace(r.FormValue("fileType")))
		dir := svcCtx.Config.Upload.Dir

		// 先解析扩展名推断文件类型，再取对应大小上限
		if fileType == "" || !validFileTypes[fileType] {
			// 由 saveTypedUpload 内部按扩展名推断（此处先给空值）
			fileType = ""
		}
		maxBytes := uploadMaxBytes(svcCtx.Config.Upload.MaxSize, svcCtx.Config.Upload.MaxMB, fileType)
		res, err := saveTypedUpload(r, "file", dir, bizType, fileType, maxBytes)
		if err != nil {
			httpx.Fail(w, 3311, err.Error())
			return
		}

		// MD5 秒传：同业务对象 + 同 MD5 已存在 → 直接返回既有记录（删除刚落盘文件）
		if exist, e := logic.New(svcCtx).FindByMD5(r.Context(), bizType, bizId, res.MD5); e == nil && exist != nil {
			if abs, ok := safeAbsPath(dir, res.RelPath); ok {
				_ = os.Remove(abs)
			}
			httpx.Ok(w, toAttachmentRow(exist))
			return
		}

		uploader := operator(r, "")
		rec, err := logic.New(svcCtx).AddAttachment(r.Context(), bizType, bizId,
			res.RelPath2FileType(), res.FileName, res.RelPath, res.Ext, res.MD5, res.MimeType, int(res.Size), uploader)
		if err != nil {
			httpx.Fail(w, 3311, "附件登记失败："+err.Error())
			return
		}
		svcCtx.EventLog.Write(r.Context(), "attachment.upload", "", uploader, "attachment", bizId,
			"上传附件 "+res.FileName, map[string]any{"bizType": bizType, "fileType": res.RelPath2FileType(), "size": res.Size})
		httpx.Ok(w, toAttachmentRow(rec))
	}
}

// AttachmentListHandler GET /attachments?bizType=&bizId= 某业务对象的附件列表
func AttachmentListHandler(svcCtx *svc.ServiceContext) http.HandlerFunc {
	return func(w http.ResponseWriter, r *http.Request) {
		q := r.URL.Query()
		data, err := logic.New(svcCtx).ListAttachments(r.Context(), q.Get("bizType"), q.Get("bizId"))
		if err != nil {
			httpx.Fail(w, 3312, err.Error())
			return
		}
		rows := make([]*attachmentRow, 0, len(data))
		for _, a := range data {
			rows = append(rows, toAttachmentRow(a))
		}
		httpx.Ok(w, map[string]any{"list": rows, "total": len(rows)})
	}
}

// AttachmentCenterHandler GET /attachment/all 附件中心（全量分页 + 磁盘状态）
// 参数：fileType / bizType / bizId / fileName / startDate / endDate / includeDeleted / page / pageSize
func AttachmentCenterHandler(svcCtx *svc.ServiceContext) http.HandlerFunc {
	return func(w http.ResponseWriter, r *http.Request) {
		q := r.URL.Query()
		page := atoiDefault(q.Get("page"), 1)
		pageSize := atoiDefault(q.Get("pageSize"), 20)
		if page < 1 {
			page = 1
		}
		if pageSize < 1 || pageSize > 200 {
			pageSize = 20
		}
		var start, end time.Time
		if v := strings.TrimSpace(q.Get("startDate")); v != "" {
			if t, err := time.ParseInLocation("2006-01-02", v, time.Local); err == nil {
				start = t
			}
		}
		if v := strings.TrimSpace(q.Get("endDate")); v != "" {
			if t, err := time.ParseInLocation("2006-01-02", v, time.Local); err == nil {
				end = t.Add(24*time.Hour - time.Second)
			}
		}
		total, list, err := logic.New(svcCtx).ListAttachmentPage(r.Context(),
			strings.ToUpper(strings.TrimSpace(q.Get("fileType"))), strings.TrimSpace(q.Get("bizType")),
			strings.TrimSpace(q.Get("bizId")), strings.TrimSpace(q.Get("fileName")),
			start, end, q.Get("includeDeleted") == "true", page, pageSize)
		if err != nil {
			httpx.Fail(w, 3312, err.Error())
			return
		}
		rows := make([]*attachmentRow, 0, len(list))
		for _, a := range list {
			rows = append(rows, toAttachmentRow(a))
		}
		httpx.Ok(w, map[string]any{
			"total": total, "list": rows, "page": page, "pageSize": pageSize,
			"disk": diskStatus(svcCtx),
		})
	}
}

// AttachmentFileHandler GET /attachment/file/:id 下载/预览（支持 Range 断点续传；?dl=1 强制下载）
func AttachmentFileHandler(svcCtx *svc.ServiceContext) http.HandlerFunc {
	return func(w http.ResponseWriter, r *http.Request) {
		id := atoiDefault(pathvar.Vars(r)["id"], 0)
		if id <= 0 {
			httpx.BadRequest(w, "id 非法")
			return
		}
		rec, err := logic.New(svcCtx).GetAttachment(r.Context(), id)
		if err != nil {
			http.NotFound(w, r)
			return
		}
		abs, ok := safeAbsPath(svcCtx.Config.Upload.Dir, rec.FilePath)
		if !ok {
			http.NotFound(w, r)
			return
		}
		if _, err := os.Stat(abs); err != nil {
			http.NotFound(w, r)
			return
		}
		// 中文文件名走 RFC 5987；下载(dl=1)才强制 attachment，否则内联预览
		disp := "inline"
		if r.URL.Query().Get("dl") == "1" {
			disp = "attachment"
		}
		w.Header().Set("Content-Disposition", fmt.Sprintf(`%s; filename*=UTF-8''%s`, disp, url.QueryEscape(rec.FileName)))
		http.ServeFile(w, r, abs) // ServeFile 自带 Range 支持
	}
}

// AttachmentDeleteHandler POST /attachment/delete {id} 逻辑删除（库内标记，物理文件交由归档任务处理）
func AttachmentDeleteHandler(svcCtx *svc.ServiceContext) http.HandlerFunc {
	return func(w http.ResponseWriter, r *http.Request) {
		var req struct {
			Id int `json:"id"`
		}
		if err := httpx.ParseJSON(r, &req); err != nil || req.Id <= 0 {
			httpx.BadRequest(w, "参数错误：id 必填")
			return
		}
		att, err := logic.New(svcCtx).DeleteAttachment(r.Context(), req.Id, operator(r, ""))
		if err != nil {
			httpx.Fail(w, 3313, "删除附件失败："+err.Error())
			return
		}
		svcCtx.EventLog.Write(r.Context(), "attachment.delete", "", operator(r, ""), "attachment", att.BizId,
			"删除附件 "+att.FileName, nil)
		httpx.OkMessage(w, "删除成功", nil)
	}
}

// AttachmentDiskStatusHandler GET /attachment/disk-status 磁盘剩余空间状态
func AttachmentDiskStatusHandler(svcCtx *svc.ServiceContext) http.HandlerFunc {
	return func(w http.ResponseWriter, r *http.Request) {
		httpx.Ok(w, diskStatus(svcCtx))
	}
}

// AttachmentArchiveHandler POST /attachment/archive {dryRun} 归档
// 把「早于本地保留年数」的附件移动到 ArchiveDir 并标记 archived=true（保留索引可追溯）。
// ArchiveDir 为空时只标记不移动；dryRun=true 时仅返回将被归档的数量。
func AttachmentArchiveHandler(svcCtx *svc.ServiceContext) http.HandlerFunc {
	return func(w http.ResponseWriter, r *http.Request) {
		var req struct {
			DryRun bool `json:"dryRun"`
		}
		_ = httpx.ParseJSON(r, &req)
		cfg := svcCtx.Config.Upload
		years := cfg.LocalRetentionYears
		if years <= 0 {
			years = 1
		}
		cutYear := time.Now().Year() - years // 早于该年份的附件可归档
		svc := logic.New(svcCtx)
		recs, err := svc.ListArchivableAttachments(r.Context())
		if err != nil {
			httpx.Fail(w, 3314, err.Error())
			return
		}
		moved, marked, failed := 0, 0, 0
		for _, rec := range recs {
			if rec.CreatedAt.Year() > cutYear-1 {
				continue
			}
			if req.DryRun {
				marked++
				continue
			}
			if cfg.ArchiveDir != "" {
				src, ok1 := safeAbsPath(cfg.Dir, rec.FilePath)
				dst, ok2 := safeAbsPath(cfg.ArchiveDir, rec.FilePath)
				if !ok1 || !ok2 {
					failed++
					continue
				}
				if err := os.MkdirAll(filepath.Dir(dst), 0o755); err != nil {
					failed++
					continue
				}
				if err := os.Rename(src, dst); err != nil {
					if err2 := copyFile(src, dst); err2 != nil {
						failed++
						continue
					}
					_ = os.Remove(src)
				}
				moved++
			}
			if err := svc.MarkArchived(r.Context(), rec.ID); err != nil {
				failed++
				continue
			}
			marked++
		}
		if !req.DryRun {
			svcCtx.EventLog.Write(r.Context(), "attachment.archive", "", operator(r, ""), "attachment", "archive",
				fmt.Sprintf("附件归档：移动%d 标记%d 失败%d（早于 %d 年）", moved, marked, failed, cutYear),
				map[string]any{"moved": moved, "marked": marked, "failed": failed})
		}
		httpx.Ok(w, map[string]any{
			"moved": moved, "marked": marked, "failed": failed,
			"cutYear": cutYear, "archiveDir": cfg.ArchiveDir, "dryRun": req.DryRun,
		})
	}
}

// copyFile 兜底复制（跨盘符 Rename 失败时用）。
func copyFile(src, dst string) error {
	in, err := os.Open(src)
	if err != nil {
		return err
	}
	defer in.Close()
	if err := os.MkdirAll(filepath.Dir(dst), 0o755); err != nil {
		return err
	}
	out, err := os.Create(dst)
	if err != nil {
		return err
	}
	if _, err := out.ReadFrom(in); err != nil {
		_ = out.Close()
		return err
	}
	return out.Close()
}