package web

import (
	"errors"
	"net/http"

	"inventree/internal/folders"
	"inventree/internal/models"
)

func (a *App) handleFolderGet(w http.ResponseWriter, r *http.Request) {
	id, err := pathID(r, "id")
	if err != nil {
		jsonErr(w, http.StatusBadRequest, err)
		return
	}
	f, err := a.Folders.Get(r.Context(), id)
	if err != nil {
		jsonErr(w, http.StatusNotFound, err)
		return
	}
	jsonOK(w, f)
}

type folderCreateRequest struct {
	Name        string `json:"name"`
	ParentID    *int64 `json:"parent_id"`
	Description string `json:"description"`
	Icon        string `json:"icon"`
	SortOrder   int    `json:"sort_order"`
}

func (a *App) handleFolderCreate(w http.ResponseWriter, r *http.Request) {
	var req folderCreateRequest
	if err := readJSON(r, &req); err != nil {
		jsonErr(w, http.StatusBadRequest, err)
		return
	}
	f := &models.Folder{Name: req.Name, ParentID: req.ParentID, Description: req.Description, Icon: req.Icon, SortOrder: req.SortOrder}
	if err := a.Folders.Create(r.Context(), f); err != nil {
		jsonErr(w, http.StatusBadRequest, err)
		return
	}
	jsonOK(w, f)
}

type folderUpdateRequest struct {
	Name        string `json:"name"`
	Description string `json:"description"`
	Icon        string `json:"icon"`
	SortOrder   int    `json:"sort_order"`
}

func (a *App) handleFolderUpdate(w http.ResponseWriter, r *http.Request) {
	id, err := pathID(r, "id")
	if err != nil {
		jsonErr(w, http.StatusBadRequest, err)
		return
	}
	var req folderUpdateRequest
	if err := readJSON(r, &req); err != nil {
		jsonErr(w, http.StatusBadRequest, err)
		return
	}
	f, err := a.Folders.Get(r.Context(), id)
	if err != nil {
		jsonErr(w, http.StatusNotFound, err)
		return
	}
	f.Name, f.Description, f.Icon, f.SortOrder = req.Name, req.Description, req.Icon, req.SortOrder
	if err := a.Folders.Update(r.Context(), f); err != nil {
		jsonErr(w, http.StatusBadRequest, err)
		return
	}
	jsonOK(w, f)
}

type folderMoveRequest struct {
	ParentID *int64 `json:"parent_id"`
}

func (a *App) handleFolderMove(w http.ResponseWriter, r *http.Request) {
	id, err := pathID(r, "id")
	if err != nil {
		jsonErr(w, http.StatusBadRequest, err)
		return
	}
	var req folderMoveRequest
	if err := readJSON(r, &req); err != nil {
		jsonErr(w, http.StatusBadRequest, err)
		return
	}
	if err := a.Folders.Move(r.Context(), id, req.ParentID); err != nil {
		status := http.StatusBadRequest
		if errors.Is(err, folders.ErrInvalidParent) {
			status = http.StatusConflict
		}
		jsonErr(w, status, err)
		return
	}
	jsonOK(w, map[string]any{"id": id, "parent_id": req.ParentID})
}

func (a *App) handleFolderDeleteInfo(w http.ResponseWriter, r *http.Request) {
	ctx := r.Context()
	id, err := pathID(r, "id")
	if err != nil {
		jsonErr(w, http.StatusBadRequest, err)
		return
	}
	folderCount, assetCount, err := a.Folders.Counts(ctx, id)
	if err != nil {
		jsonErr(w, http.StatusInternalServerError, err)
		return
	}
	f, err := a.Folders.Get(ctx, id)
	if err != nil {
		jsonErr(w, http.StatusNotFound, err)
		return
	}

	all, err := a.Folders.All(ctx)
	if err != nil {
		jsonErr(w, http.StatusInternalServerError, err)
		return
	}
	descendants := map[int64]bool{id: true}
	changed := true
	for changed {
		changed = false
		for _, cand := range all {
			if cand.ParentID != nil && descendants[*cand.ParentID] && !descendants[cand.ID] {
				descendants[cand.ID] = true
				changed = true
			}
		}
	}
	byID := map[int64]models.Folder{}
	for _, cand := range all {
		byID[cand.ID] = cand
	}
	var pathOf func(int64) string
	pathOf = func(fid int64) string {
		ff, ok := byID[fid]
		if !ok {
			return ""
		}
		if ff.ParentID == nil {
			return ff.Name
		}
		return pathOf(*ff.ParentID) + " / " + ff.Name
	}

	type dest struct {
		ID   int64  `json:"id"`
		Path string `json:"path"`
	}
	destinations := []dest{{ID: 0, Path: "Inventory (top level)"}}
	for _, cand := range all {
		if descendants[cand.ID] {
			continue
		}
		destinations = append(destinations, dest{ID: cand.ID, Path: pathOf(cand.ID)})
	}

	jsonOK(w, map[string]any{
		"folder_name":  f.Name,
		"folder_count": folderCount,
		"asset_count":  assetCount,
		"destinations": destinations,
	})
}

func (a *App) handleFolderDelete(w http.ResponseWriter, r *http.Request) {
	ctx := r.Context()
	id, err := pathID(r, "id")
	if err != nil {
		jsonErr(w, http.StatusBadRequest, err)
		return
	}

	mode := r.URL.Query().Get("mode")
	switch mode {
	case "relocate":
		var dest *int64
		if raw := r.URL.Query().Get("dest"); raw != "" && raw != "0" {
			d, err := queryOptionalID(r, "dest")
			if err != nil {
				jsonErr(w, http.StatusBadRequest, err)
				return
			}
			dest = d
		}
		if err := a.Folders.DeleteAndRelocate(ctx, id, dest); err != nil {
			jsonErr(w, http.StatusBadRequest, err)
			return
		}
	case "cascade":
		if err := a.Folders.CascadeDelete(ctx, id); err != nil {
			jsonErr(w, http.StatusBadRequest, err)
			return
		}
	default:
		if err := a.Folders.Delete(ctx, id); err != nil {
			status := http.StatusBadRequest
			if errors.Is(err, folders.ErrNotEmpty) {
				status = http.StatusConflict
			}
			jsonErr(w, status, err)
			return
		}
	}
	jsonOK(w, map[string]any{"id": id})
}