package controller

import (
	"fmt"
	"net/http"
	"strconv"
	"time"

	"seeyon-filesystem/config"
	"seeyon-filesystem/dto"
	"seeyon-filesystem/middleware"
	"seeyon-filesystem/model"
	"seeyon-filesystem/service"
	"seeyon-filesystem/storage"
	"seeyon-filesystem/utils"

	"github.com/gin-gonic/gin"
)

// OpenAPIFileController 对外文件API控制器
type OpenAPIFileController struct {
	fileService   *service.FileService
	folderService *service.FolderService
	chunkService  *service.ChunkUploadService
}

func NewOpenAPIFileController() *OpenAPIFileController {
	return &OpenAPIFileController{
		fileService:   service.NewFileService(),
		folderService: service.NewFolderService(),
		chunkService:  service.NewChunkUploadService(),
	}
}

// ========== 1. 根据父文件夹ID分页查询 ==========

// ListByFolder 分页查询文件夹下的文件和子文件夹
// GET /api/openapi/files?folder_id=0&page=1&page_size=20
// 返回树状结构: 文件夹 + 文件
func (c *OpenAPIFileController) ListByFolder(ctx *gin.Context) {
	userID := middleware.GetCurrentUserID(ctx)

	folderIDStr := ctx.DefaultQuery("folder_id", "0")
	folderID, _ := strconv.ParseUint(folderIDStr, 10, 64)
	page, _ := strconv.Atoi(ctx.DefaultQuery("page", "1"))
	pageSize, _ := strconv.Atoi(ctx.DefaultQuery("page_size", "50"))
	if page < 1 {
		page = 1
	}
	if pageSize < 1 || pageSize > 200 {
		pageSize = 50
	}

	// 获取用户角色
	roleIDs := getUserRoleIDs(userID)

	// 查询文件夹
	folders, err := getFoldersByParent(folderID, userID, page, pageSize)
	if err != nil {
		utils.ServerError(ctx, "查询文件夹失败")
		return
	}

	// 查询文件
	files, totalFiles, err := getFilesByFolder(folderID, userID, roleIDs, page, pageSize)
	if err != nil {
		utils.ServerError(ctx, "查询文件失败")
		return
	}

	// 组装树状结构
	result := dto.OpenAPIListResult{
		FolderID:   folderID,
		TotalFiles: totalFiles,
		Page:       page,
		PageSize:   pageSize,
	}

	for _, f := range folders {
		childCount := getFolderChildCount(f.ID)
		result.Folders = append(result.Folders, dto.OpenAPIFolderVO{
			ID:         dto.StringID(f.ID),
			Name:       f.Name,
			ParentID:   dto.StringID(f.ParentID),
			ChildCount: childCount,
			CreatedAt:  f.CreatedAt.Format("2006-01-02 15:04:05"),
		})
	}

	for _, f := range files {
		result.Files = append(result.Files, dto.OpenAPIFileVO{
			ID:          dto.StringID(f.ID),
			Name:        f.Name,
			Extension:   f.Extension,
			Size:        f.Size,
			MD5:         f.MD5,
			MimeType:    f.MimeType,
			DownloadURL: getCDNOrPresignedURL(&f),
			CreatedAt:   f.CreatedAt.Format("2006-01-02 15:04:05"),
		})
	}

	utils.Success(ctx, result)
}

// ========== 2. 按名称搜索返回树状结构 ==========

// SearchTree 按文件名/文件夹名搜索, 返回树状结构
// GET /api/openapi/files/search?keyword=报告&page=1&page_size=20
func (c *OpenAPIFileController) SearchTree(ctx *gin.Context) {
	userID := middleware.GetCurrentUserID(ctx)
	keyword := ctx.Query("keyword")
	if keyword == "" {
		utils.BadRequest(ctx, "请输入搜索关键词")
		return
	}

	page, _ := strconv.Atoi(ctx.DefaultQuery("page", "1"))
	pageSize, _ := strconv.Atoi(ctx.DefaultQuery("page_size", "50"))
	if page < 1 {
		page = 1
	}
	if pageSize < 1 || pageSize > 200 {
		pageSize = 50
	}

	roleIDs := getUserRoleIDs(userID)

	// 搜索文件
	files, total, err := searchFilesByName(userID, roleIDs, keyword, page, pageSize)
	if err != nil {
		utils.ServerError(ctx, "搜索失败")
		return
	}

	// 搜索文件夹
	folders, err := searchFoldersByName(userID, keyword, page, pageSize)
	if err != nil {
		utils.ServerError(ctx, "搜索失败")
		return
	}

	result := dto.OpenAPISearchResult{
		Keyword:    keyword,
		TotalFiles: total,
		Page:       page,
		PageSize:   pageSize,
	}

	for _, f := range folders {
		result.Folders = append(result.Folders, dto.OpenAPIFolderVO{
			ID:        dto.StringID(f.ID),
			Name:      f.Name,
			ParentID:  dto.StringID(f.ParentID),
			CreatedAt: f.CreatedAt.Format("2006-01-02 15:04:05"),
		})
	}

	for _, f := range files {
		result.Files = append(result.Files, dto.OpenAPIFileVO{
			ID:          dto.StringID(f.ID),
			Name:        f.Name,
			Extension:   f.Extension,
			Size:        f.Size,
			MD5:         f.MD5,
			MimeType:    f.MimeType,
			DownloadURL: getCDNOrPresignedURL(&f),
			CreatedAt:   f.CreatedAt.Format("2006-01-02 15:04:05"),
		})
	}

	utils.Success(ctx, result)
}

// ========== 3. 分片上传/下载 ==========

// ChunkUploadInit 初始化分片上传
// POST /api/openapi/files/upload/init
func (c *OpenAPIFileController) ChunkUploadInit(ctx *gin.Context) {
	userID := middleware.GetCurrentUserID(ctx)

	var req dto.ChunkUploadInitRequest
	if err := ctx.ShouldBindJSON(&req); err != nil {
		utils.BadRequest(ctx, "参数错误: "+err.Error())
		return
	}

	result, err := c.chunkService.InitUpload(req.FileName, req.FileSize, req.MD5, uint64(req.FolderID), userID, req.PolicyID)
	if err != nil {
		utils.ServerError(ctx, err.Error())
		return
	}

	utils.Success(ctx, result)
}

// ChunkUpload 上传分片
// PUT /api/openapi/files/upload/chunk/:uploadId/:index
func (c *OpenAPIFileController) ChunkUpload(ctx *gin.Context) {
	uploadID := ctx.Param("uploadId")
	indexStr := ctx.Param("index")
	index, err := strconv.Atoi(indexStr)
	if err != nil {
		utils.BadRequest(ctx, "分片索引无效")
		return
	}

	checksum := ctx.GetHeader("X-Checksum")

	file, err := ctx.FormFile("chunk")
	if err != nil {
		utils.BadRequest(ctx, "请上传分片文件")
		return
	}

	reader, err := file.Open()
	if err != nil {
		utils.BadRequest(ctx, "读取分片失败")
		return
	}
	defer reader.Close()

	result, err := c.chunkService.UploadChunk(uploadID, index, reader, checksum)
	if err != nil {
		utils.BadRequest(ctx, err.Error())
		return
	}

	utils.Success(ctx, result)
}

// ChunkMerge 合并分片
// POST /api/openapi/files/upload/merge/:uploadId
func (c *OpenAPIFileController) ChunkMerge(ctx *gin.Context) {
	uploadID := ctx.Param("uploadId")

	result, err := c.chunkService.MergeChunks(uploadID)
	if err != nil {
		utils.ServerError(ctx, err.Error())
		return
	}

	utils.Success(ctx, result)
}

// ChunkProgress 查询上传进度
// GET /api/openapi/files/upload/progress/:uploadId
func (c *OpenAPIFileController) ChunkProgress(ctx *gin.Context) {
	uploadID := ctx.Param("uploadId")

	result, err := c.chunkService.GetUploadProgress(uploadID)
	if err != nil {
		utils.NotFound(ctx, err.Error())
		return
	}

	utils.Success(ctx, result)
}

// Download 下载文件
// GET /api/openapi/files/:id/download
func (c *OpenAPIFileController) Download(ctx *gin.Context) {
	userID := middleware.GetCurrentUserID(ctx)
	fileID, err := strconv.ParseUint(ctx.Param("id"), 10, 64)
	if err != nil {
		utils.BadRequest(ctx, "无效的文件ID")
		return
	}

	reader, file, err := c.fileService.Download(fileID, userID)
	if err != nil {
		utils.ServerError(ctx, err.Error())
		return
	}
	defer reader.Close()

	ctx.Header("Content-Disposition", fmt.Sprintf("attachment; filename=\"%s\"", file.Name))
	ctx.Header("Content-Type", file.MimeType)
	ctx.Header("Content-Length", strconv.FormatInt(file.Size, 10))
	ctx.DataFromReader(http.StatusOK, file.Size, file.MimeType, reader, nil)
}

// Preview 预览文件
// GET /api/openapi/files/:id/preview
func (c *OpenAPIFileController) Preview(ctx *gin.Context) {
	userID := middleware.GetCurrentUserID(ctx)
	fileID, err := strconv.ParseUint(ctx.Param("id"), 10, 64)
	if err != nil {
		utils.BadRequest(ctx, "无效的文件ID")
		return
	}

	reader, file, err := c.fileService.Download(fileID, userID)
	if err != nil {
		utils.ServerError(ctx, err.Error())
		return
	}
	defer reader.Close()

	ctx.Header("Content-Disposition", fmt.Sprintf("inline; filename=\"%s\"", file.Name))
	ctx.Header("Content-Type", file.MimeType)
	ctx.Header("Content-Length", strconv.FormatInt(file.Size, 10))
	ctx.DataFromReader(http.StatusOK, file.Size, file.MimeType, reader, nil)
}

// ========== 辅助函数 ==========

func getUserRoleIDs(userID uint64) []uint64 {
	var userRoles []model.UserRole
	config.DB.Where("user_id = ?", userID).Find(&userRoles)
	ids := make([]uint64, 0, len(userRoles))
	for _, ur := range userRoles {
		ids = append(ids, ur.RoleID)
	}
	return ids
}

func getFoldersByParent(parentID, ownerID uint64, page, pageSize int) ([]model.Folder, error) {
	var folders []model.Folder
	err := config.DB.Where("parent_id = ? AND owner_id = ? AND status = 1", parentID, ownerID).
		Order("name ASC").Offset((page - 1) * pageSize).Limit(pageSize).Find(&folders).Error
	return folders, err
}

func getFilesByFolder(folderID, userID uint64, roleIDs []uint64, page, pageSize int) ([]model.File, int64, error) {
	var files []model.File
	query := config.DB.Where("folder_id = ? AND owner_id = ? AND status = 1", folderID, userID)
	var total int64
	query.Model(&model.File{}).Count(&total)
	err := query.Order("name ASC").Offset((page - 1) * pageSize).Limit(pageSize).Find(&files).Error
	return files, total, err
}

func getFolderChildCount(folderID uint64) int64 {
	var count int64
	config.DB.Model(&model.Folder{}).Where("parent_id = ? AND status = 1", folderID).Count(&count)
	return count
}

func searchFilesByName(userID uint64, roleIDs []uint64, keyword string, page, pageSize int) ([]model.File, int64, error) {
	var files []model.File
	query := config.DB.Where("owner_id = ? AND status = 1 AND name LIKE ?", userID, "%"+keyword+"%")
	var total int64
	query.Model(&model.File{}).Count(&total)
	err := query.Order("created_at DESC").Offset((page - 1) * pageSize).Limit(pageSize).Find(&files).Error
	return files, total, err
}

func searchFoldersByName(ownerID uint64, keyword string, page, pageSize int) ([]model.Folder, error) {
	var folders []model.Folder
	err := config.DB.Where("owner_id = ? AND status = 1 AND name LIKE ?", ownerID, "%"+keyword+"%").
		Order("name ASC").Offset((page - 1) * pageSize).Limit(pageSize).Find(&folders).Error
	return folders, err
}

func getCDNOrPresignedURL(file *model.File) string {
	if file.StorageKey == "" {
		return ""
	}
	engine, err := storage.GetEngineByPolicyID(file.StoragePolicyID)
	if err != nil {
		return ""
	}
	if localEngine, ok := engine.(*storage.LocalEngine); ok {
		return localEngine.GetURL(file.StorageKey)
	}
	if minioEngine, ok := engine.(*storage.MinIOEngine); ok {
		url, err := minioEngine.GetPresignedURL(file.StorageKey, 24*time.Hour)
		if err == nil {
			return url
		}
	}
	return ""
}