package handlers

import (
	"fmt"
	"net/http"
	"path/filepath"
	"strings"
	"time"

	"github.com/flatrender/file-svc/internal/db"
	"github.com/flatrender/file-svc/internal/middleware"
	"github.com/flatrender/file-svc/internal/models"
	"github.com/flatrender/file-svc/internal/storage"
	"github.com/gin-gonic/gin"
	"github.com/google/uuid"
	"github.com/jackc/pgx/v5"
)

type FileHandler struct {
	store    *db.Store
	minio    *storage.MinioClient
	bucket   string // default upload bucket name
}

func NewFileHandler(store *db.Store, minio *storage.MinioClient, bucket string) *FileHandler {
	return &FileHandler{store: store, minio: minio, bucket: bucket}
}

// GET /v1/files
func (h *FileHandler) ListFiles(c *gin.Context) {
	userID := c.MustGet(middleware.KeyUserID).(uuid.UUID)

	var req models.FileListRequest
	if err := c.ShouldBindQuery(&req); err != nil {
		c.JSON(http.StatusBadRequest, models.ErrorResponse{Error: models.APIError{Code: "bad_request", Message: err.Error()}})
		return
	}
	if req.Page < 1 {
		req.Page = 1
	}
	if req.PageSize < 1 || req.PageSize > 100 {
		req.PageSize = 20
	}

	files, total, err := h.store.ListFiles(c.Request.Context(), userID, req)
	if err != nil {
		c.JSON(http.StatusInternalServerError, models.ErrorResponse{Error: models.APIError{Code: "db_error", Message: err.Error()}})
		return
	}

	if files == nil {
		files = []models.UserFile{}
	}

	c.JSON(http.StatusOK, models.PagedResponse[models.UserFile]{
		Items: files,
		Meta:  models.PaginationMeta{Page: req.Page, PageSize: req.PageSize, Total: total, TotalPages: db.TotalPages(total, req.PageSize)},
	})
}

// GET /v1/files/:id
func (h *FileHandler) GetFile(c *gin.Context) {
	userID := c.MustGet(middleware.KeyUserID).(uuid.UUID)
	id, err := uuid.Parse(c.Param("id"))
	if err != nil {
		c.JSON(http.StatusBadRequest, models.ErrorResponse{Error: models.APIError{Code: "bad_request", Message: "invalid id"}})
		return
	}

	file, err := h.store.GetFile(c.Request.Context(), id, userID)
	if err == pgx.ErrNoRows {
		c.JSON(http.StatusNotFound, models.ErrorResponse{Error: models.APIError{Code: "not_found", Message: "file not found"}})
		return
	}
	if err != nil {
		c.JSON(http.StatusInternalServerError, models.ErrorResponse{Error: models.APIError{Code: "db_error", Message: err.Error()}})
		return
	}

	c.JSON(http.StatusOK, file)
}

// POST /v1/files/presigned-upload
func (h *FileHandler) PresignedUpload(c *gin.Context) {
	userID := c.MustGet(middleware.KeyUserID).(uuid.UUID)
	tenantID := c.MustGet(middleware.KeyTenantID).(uuid.UUID)

	var req models.PresignedUploadRequest
	if err := c.ShouldBindJSON(&req); err != nil {
		c.JSON(http.StatusBadRequest, models.ErrorResponse{Error: models.APIError{Code: "bad_request", Message: err.Error()}})
		return
	}

	if err := h.store.EnsureQuota(c.Request.Context(), userID, tenantID); err != nil {
		c.JSON(http.StatusInternalServerError, models.ErrorResponse{Error: models.APIError{Code: "db_error", Message: err.Error()}})
		return
	}

	ext := strings.ToLower(filepath.Ext(req.Filename))
	key := fmt.Sprintf("uploads/%s/%s%s", userID, uuid.New(), ext)

	uploadURL, err := h.minio.PresignedPutURL(c.Request.Context(), h.bucket, key, 15*time.Minute)
	if err != nil {
		c.JSON(http.StatusInternalServerError, models.ErrorResponse{Error: models.APIError{Code: "storage_error", Message: err.Error()}})
		return
	}

	fileKind := guessFileKind(ext, req.MimeType)
	file := &models.UserFile{
		TenantID:         tenantID,
		UserID:           userID,
		UserFolderID:     req.TargetFolderID,
		Name:             req.Filename,
		OriginalFilename: &req.Filename,
		FileExtension:    &ext,
		MimeType:         req.MimeType,
		FileType:         fileKind,
		MinioBucket:      h.bucket,
		MinioKey:         key,
		FileAddress:      fmt.Sprintf("minio://%s/%s", h.bucket, key),
		SizeBytes:        req.SizeBytes,
		UploadStatus:     models.UploadStatusPending,
		Source:           strPtr("upload"),
	}

	if err := h.store.CreateFileRecord(c.Request.Context(), file); err != nil {
		c.JSON(http.StatusInternalServerError, models.ErrorResponse{Error: models.APIError{Code: "db_error", Message: err.Error()}})
		return
	}

	c.JSON(http.StatusOK, models.PresignedUploadResponse{
		UploadURL: uploadURL,
		FileID:    file.ID,
		ExpiresAt: time.Now().Add(15 * time.Minute),
	})
}

// POST /v1/files/:id/confirm
func (h *FileHandler) ConfirmUpload(c *gin.Context) {
	userID := c.MustGet(middleware.KeyUserID).(uuid.UUID)
	id, err := uuid.Parse(c.Param("id"))
	if err != nil {
		c.JSON(http.StatusBadRequest, models.ErrorResponse{Error: models.APIError{Code: "bad_request", Message: "invalid id"}})
		return
	}

	file, err := h.store.GetFile(c.Request.Context(), id, userID)
	if err == pgx.ErrNoRows {
		c.JSON(http.StatusNotFound, models.ErrorResponse{Error: models.APIError{Code: "not_found", Message: "file not found"}})
		return
	}
	if err != nil {
		c.JSON(http.StatusInternalServerError, models.ErrorResponse{Error: models.APIError{Code: "db_error", Message: err.Error()}})
		return
	}

	if err := h.store.MarkFileReady(c.Request.Context(), id, nil); err != nil {
		c.JSON(http.StatusInternalServerError, models.ErrorResponse{Error: models.APIError{Code: "db_error", Message: err.Error()}})
		return
	}

	if err := h.store.AddUsedBytes(c.Request.Context(), userID, file.SizeBytes); err != nil {
		c.JSON(http.StatusInternalServerError, models.ErrorResponse{Error: models.APIError{Code: "db_error", Message: err.Error()}})
		return
	}

	c.JSON(http.StatusOK, gin.H{"status": "ready"})
}

// DELETE /v1/files/:id
func (h *FileHandler) DeleteFile(c *gin.Context) {
	userID := c.MustGet(middleware.KeyUserID).(uuid.UUID)
	id, err := uuid.Parse(c.Param("id"))
	if err != nil {
		c.JSON(http.StatusBadRequest, models.ErrorResponse{Error: models.APIError{Code: "bad_request", Message: "invalid id"}})
		return
	}

	file, err := h.store.DeleteFile(c.Request.Context(), id, userID)
	if err == pgx.ErrNoRows {
		c.JSON(http.StatusNotFound, models.ErrorResponse{Error: models.APIError{Code: "not_found", Message: "file not found"}})
		return
	}
	if err != nil {
		c.JSON(http.StatusInternalServerError, models.ErrorResponse{Error: models.APIError{Code: "db_error", Message: err.Error()}})
		return
	}

	_ = h.minio.DeleteObject(c.Request.Context(), file.MinioBucket, file.MinioKey)
	_ = h.store.AddUsedBytes(c.Request.Context(), userID, -file.SizeBytes)

	c.Status(http.StatusNoContent)
}

// GET /v1/files/:id/download
func (h *FileHandler) GetDownloadURL(c *gin.Context) {
	userID := c.MustGet(middleware.KeyUserID).(uuid.UUID)
	id, err := uuid.Parse(c.Param("id"))
	if err != nil {
		c.JSON(http.StatusBadRequest, models.ErrorResponse{Error: models.APIError{Code: "bad_request", Message: "invalid id"}})
		return
	}

	file, err := h.store.GetFile(c.Request.Context(), id, userID)
	if err == pgx.ErrNoRows {
		c.JSON(http.StatusNotFound, models.ErrorResponse{Error: models.APIError{Code: "not_found", Message: "file not found"}})
		return
	}
	if err != nil {
		c.JSON(http.StatusInternalServerError, models.ErrorResponse{Error: models.APIError{Code: "db_error", Message: err.Error()}})
		return
	}

	dlURL, err := h.minio.PresignedGetURL(c.Request.Context(), file.MinioBucket, file.MinioKey, time.Hour)
	if err != nil {
		c.JSON(http.StatusInternalServerError, models.ErrorResponse{Error: models.APIError{Code: "storage_error", Message: err.Error()}})
		return
	}

	c.JSON(http.StatusOK, gin.H{"url": dlURL, "expires_in": 3600})
}

// GET /v1/quota
func (h *FileHandler) GetQuota(c *gin.Context) {
	userID := c.MustGet(middleware.KeyUserID).(uuid.UUID)
	tenantID := c.MustGet(middleware.KeyTenantID).(uuid.UUID)

	if err := h.store.EnsureQuota(c.Request.Context(), userID, tenantID); err != nil {
		c.JSON(http.StatusInternalServerError, models.ErrorResponse{Error: models.APIError{Code: "db_error", Message: err.Error()}})
		return
	}

	quota, err := h.store.GetQuota(c.Request.Context(), userID)
	if err != nil {
		c.JSON(http.StatusInternalServerError, models.ErrorResponse{Error: models.APIError{Code: "db_error", Message: err.Error()}})
		return
	}

	c.JSON(http.StatusOK, quota)
}

// ── Folders ───────────────────────────────────────────────────────────────────

// GET /v1/folders
func (h *FileHandler) ListFolders(c *gin.Context) {
	userID := c.MustGet(middleware.KeyUserID).(uuid.UUID)

	var parentID *uuid.UUID
	if p := c.Query("parent_id"); p != "" {
		id, err := uuid.Parse(p)
		if err != nil {
			c.JSON(http.StatusBadRequest, models.ErrorResponse{Error: models.APIError{Code: "bad_request", Message: "invalid parent_id"}})
			return
		}
		parentID = &id
	}

	folders, err := h.store.GetFolders(c.Request.Context(), userID, parentID)
	if err != nil {
		c.JSON(http.StatusInternalServerError, models.ErrorResponse{Error: models.APIError{Code: "db_error", Message: err.Error()}})
		return
	}

	if folders == nil {
		folders = []models.UserFolder{}
	}
	c.JSON(http.StatusOK, folders)
}

// POST /v1/folders
func (h *FileHandler) CreateFolder(c *gin.Context) {
	userID := c.MustGet(middleware.KeyUserID).(uuid.UUID)
	tenantID := c.MustGet(middleware.KeyTenantID).(uuid.UUID)

	var req models.CreateFolderRequest
	if err := c.ShouldBindJSON(&req); err != nil {
		c.JSON(http.StatusBadRequest, models.ErrorResponse{Error: models.APIError{Code: "bad_request", Message: err.Error()}})
		return
	}

	folder, err := h.store.CreateFolder(c.Request.Context(), tenantID, userID, req)
	if err != nil {
		c.JSON(http.StatusInternalServerError, models.ErrorResponse{Error: models.APIError{Code: "db_error", Message: err.Error()}})
		return
	}

	c.JSON(http.StatusCreated, folder)
}

// DELETE /v1/folders/:id
func (h *FileHandler) DeleteFolder(c *gin.Context) {
	userID := c.MustGet(middleware.KeyUserID).(uuid.UUID)
	id, err := uuid.Parse(c.Param("id"))
	if err != nil {
		c.JSON(http.StatusBadRequest, models.ErrorResponse{Error: models.APIError{Code: "bad_request", Message: "invalid id"}})
		return
	}

	if err := h.store.DeleteFolder(c.Request.Context(), id, userID); err == pgx.ErrNoRows {
		c.JSON(http.StatusNotFound, models.ErrorResponse{Error: models.APIError{Code: "not_found", Message: "folder not found"}})
		return
	} else if err != nil {
		c.JSON(http.StatusInternalServerError, models.ErrorResponse{Error: models.APIError{Code: "db_error", Message: err.Error()}})
		return
	}

	c.Status(http.StatusNoContent)
}

// ── Helpers ───────────────────────────────────────────────────────────────────

func guessFileKind(ext string, mime *string) models.FileKind {
	if mime != nil {
		switch {
		case strings.HasPrefix(*mime, "video/"):
			return models.FileKindVideo
		case strings.HasPrefix(*mime, "image/"):
			return models.FileKindImage
		case strings.HasPrefix(*mime, "audio/"):
			return models.FileKindAudio
		}
	}
	switch ext {
	case ".mp4", ".mov", ".avi", ".webm", ".mkv":
		return models.FileKindVideo
	case ".jpg", ".jpeg", ".png", ".gif", ".webp", ".svg":
		return models.FileKindImage
	case ".mp3", ".wav", ".ogg", ".aac", ".flac":
		return models.FileKindAudio
	}
	return models.FileKindOther
}

func strPtr(s string) *string { return &s }