package httpapi

import (
	"io"
	"net/http"
	"net/url"
	"os"
	"path/filepath"
	"time"

	"git.yeij.top/AskaEth/Scoreboard/server/internal/auth"
	"git.yeij.top/AskaEth/Scoreboard/server/internal/export"
)

const xlsxMIME = "application/vnd.openxmlformats-officedocument.spreadsheetml.sheet"

// exportRoutes 挂载 xlsx 导出、赛事项目包与备份查询。
func (s *server) exportRoutes(mux *http.ServeMux) {
	mux.HandleFunc("GET /api/export/standings.xlsx", s.read(auth.RoleGuest, s.exportStandingsXLSX))
	mux.HandleFunc("GET /api/export/all.xlsx", s.read(auth.RoleGuest, s.exportAllXLSX))
	// Go 1.22 ServeMux 的通配段必须独占一段，所以分项/单位导出用 /{id}，文件名由响应头给出。
	mux.HandleFunc("GET /api/export/events/{id}", s.read(auth.RoleGuest, s.exportEventXLSX))
	mux.HandleFunc("GET /api/export/teams/{id}", s.read(auth.RoleGuest, s.exportTeamXLSX))

	mux.HandleFunc("GET /api/export/project.zip", s.read(auth.RoleAdmin, s.exportProjectZip))
	mux.HandleFunc("POST /api/export/project/import", s.write(auth.RoleAdmin, s.importProjectZip))
	mux.HandleFunc("GET /api/export/backups", s.read(auth.RoleAdmin, s.listBackups))
}

// streamDownload 直接写响应体；返回 errHandled 让统一响应层不再追加 JSON。
func (s *server) streamDownload(w http.ResponseWriter, filename, contentType string, write func(io.Writer) error) (any, error) {
	w.Header().Set("Content-Type", contentType)
	w.Header().Set("Content-Disposition", "attachment; filename*=UTF-8''"+url.PathEscape(filename))
	if err := write(w); err != nil {
		s.logger.Error("导出写出失败", "file", filename, "err", err)
	}
	return nil, errHandled
}

func (s *server) exportStandingsXLSX(w http.ResponseWriter, r *http.Request) (any, error) {
	wb, err := export.LoadStandingsWorkbook(s.ev, export.Options{})
	if err != nil {
		return nil, internal(err)
	}
	return s.streamDownload(w, "总积分榜.xlsx", xlsxMIME, func(out io.Writer) error {
		return export.WriteStandingsXLSX(out, wb)
	})
}

func (s *server) exportEventXLSX(w http.ResponseWriter, r *http.Request) (any, error) {
	id, err := pathID(r, "id")
	if err != nil {
		return nil, err
	}
	wb, err := export.LoadEventWorkbook(s.ev, id, export.Options{})
	if err != nil {
		return nil, internal(err)
	}
	return s.streamDownload(w, "分项成绩表.xlsx", xlsxMIME, func(out io.Writer) error {
		return export.WriteEventXLSX(out, wb)
	})
}

func (s *server) exportAllXLSX(w http.ResponseWriter, r *http.Request) (any, error) {
	wb, err := export.LoadAllWorkbook(s.ev, export.Options{})
	if err != nil {
		return nil, internal(err)
	}
	return s.streamDownload(w, "赛事成绩总表.xlsx", xlsxMIME, func(out io.Writer) error {
		return export.WriteAllXLSX(out, wb)
	})
}

func (s *server) exportTeamXLSX(w http.ResponseWriter, r *http.Request) (any, error) {
	id, err := pathID(r, "id")
	if err != nil {
		return nil, err
	}
	wb, err := export.LoadTeamDetailWorkbook(s.ev, id, export.Options{})
	if err != nil {
		return nil, internal(err)
	}
	return s.streamDownload(w, "单位积分明细.xlsx", xlsxMIME, func(out io.Writer) error {
		return export.WriteTeamDetailXLSX(out, wb)
	})
}

func (s *server) exportProjectZip(w http.ResponseWriter, r *http.Request) (any, error) {
	dir := filepath.Join(s.dataDir, "exports")
	if err := os.MkdirAll(dir, 0o755); err != nil {
		return nil, internal(err)
	}
	dst := filepath.Join(dir, "project-"+time.Now().Format("20060102-150405")+".zip")
	if _, err := export.ExportProjectZip(s.ev, dst, export.ProjectExportOptions{}); err != nil {
		return nil, internal(err)
	}
	defer func() { _ = os.Remove(dst) }()

	w.Header().Set("Content-Type", "application/zip")
	w.Header().Set("Content-Disposition", "attachment; filename*=UTF-8''"+url.PathEscape("赛事项目包.zip"))
	http.ServeFile(w, r, dst)
	return nil, errHandled
}

func (s *server) importProjectZip(w http.ResponseWriter, r *http.Request) (any, error) {
	if err := r.ParseMultipartForm(512 << 20); err != nil {
		return nil, badRequest("解析上传失败", nil)
	}
	file, _, err := r.FormFile("file")
	if err != nil {
		return nil, badRequest("缺少上传字段 file", nil)
	}
	defer func() { _ = file.Close() }()

	tmpDir, err := os.MkdirTemp("", "scoreboard-import-")
	if err != nil {
		return nil, internal(err)
	}
	defer func() { _ = os.RemoveAll(tmpDir) }()

	tmp := filepath.Join(tmpDir, "project.zip")
	out, err := os.Create(tmp)
	if err != nil {
		return nil, internal(err)
	}
	if _, err := io.Copy(out, file); err != nil {
		_ = out.Close()
		return nil, internal(err)
	}
	if err := out.Close(); err != nil {
		return nil, internal(err)
	}

	res, err := export.ImportProjectZip(tmp, filepath.Join(s.dataDir, "event_projs"), export.ImportOptions{
		Overwrite: r.FormValue("overwrite") == "1",
		Rename:    r.FormValue("rename"),
	})
	if err != nil {
		return nil, badRequest(err.Error(), nil)
	}
	return res, nil
}

func (s *server) listBackups(w http.ResponseWriter, r *http.Request) (any, error) {
	items, err := export.ListBackups(filepath.Join(s.dataDir, "backups"), "")
	if err != nil {
		return nil, internal(err)
	}
	return items, nil
}