package web

import (
	"context"
	"net/http"

	"inventree/internal/assets"
	"inventree/internal/models"
)

// InventoryPageData is the top-level data passed to templates/pages/inventory.html.
type InventoryPageData struct {
	User      *models.User
	Tree      []models.TreeNode
	Root      *RootPanelData
	ItemTypes []models.ItemType
	Statuses  []models.Status
}

func (a *App) handleInventoryPage(w http.ResponseWriter, r *http.Request) {
	ctx := r.Context()
	u := currentUser(r)

	expanded, err := a.expandedFolderIDs(ctx, u.ID)
	if err != nil {
		writeErr(w, http.StatusInternalServerError, err.Error())
		return
	}
	tree, err := a.buildTree(ctx, nil, expanded)
	if err != nil {
		writeErr(w, http.StatusInternalServerError, err.Error())
		return
	}
	root, err := a.rootPanelData(ctx)
	if err != nil {
		writeErr(w, http.StatusInternalServerError, err.Error())
		return
	}
	itemTypes, err := a.ItemTypes.List(ctx, false)
	if err != nil {
		writeErr(w, http.StatusInternalServerError, err.Error())
		return
	}
	statusList, err := a.Statuses.List(ctx)
	if err != nil {
		writeErr(w, http.StatusInternalServerError, err.Error())
		return
	}

	a.Render(w, http.StatusOK, "inventory", InventoryPageData{
		User: u, Tree: tree, Root: root, ItemTypes: itemTypes, Statuses: statusList,
	})
}

// handleTreeChildren serves one level of the tree lazily for AJAX expand.
// When persist=1, the expanded state is remembered for the current user.
func (a *App) handleTreeChildren(w http.ResponseWriter, r *http.Request) {
	ctx := r.Context()
	u := currentUser(r)

	parentID, err := queryOptionalID(r, "parent_id")
	if err != nil {
		writeErr(w, http.StatusBadRequest, "invalid parent_id")
		return
	}
	if r.URL.Query().Get("persist") == "1" && parentID != nil {
		if err := a.persistExpand(ctx, u.ID, *parentID); err != nil {
			a.Log.Warn("persist expand failed", "error", err)
		}
	}

	// Honor already-persisted expand state for descendants so that
	// re-fetching a branch (e.g. after a drag-and-drop move) doesn't
	// visually collapse folders the user had already opened.
	expanded, err := a.expandedFolderIDs(ctx, u.ID)
	if err != nil {
		writeErr(w, http.StatusInternalServerError, err.Error())
		return
	}
	nodes, err := a.buildTree(ctx, parentID, expanded)
	if err != nil {
		writeErr(w, http.StatusInternalServerError, err.Error())
		return
	}
	a.RenderFragment(w, http.StatusOK, "tree_children", nodes)
}

func (a *App) handleTreeCollapse(w http.ResponseWriter, r *http.Request) {
	u := currentUser(r)
	if err := r.ParseForm(); err != nil {
		writeErr(w, http.StatusBadRequest, "invalid form")
		return
	}
	folderID := queryInt64(r, "folder_id")
	if folderID == 0 {
		writeErr(w, http.StatusBadRequest, "folder_id is required")
		return
	}
	if err := a.persistCollapse(r.Context(), u.ID, folderID); err != nil {
		writeErr(w, http.StatusInternalServerError, err.Error())
		return
	}
	w.WriteHeader(http.StatusNoContent)
}

func (a *App) handleTreeCollapseAll(w http.ResponseWriter, r *http.Request) {
	u := currentUser(r)
	if err := a.persistCollapseAll(r.Context(), u.ID); err != nil {
		writeErr(w, http.StatusInternalServerError, err.Error())
		return
	}
	w.WriteHeader(http.StatusNoContent)
}

// RootPanelData backs the main panel when nothing is selected: the virtual
// "Inventory" root, showing top-level folders, unfiled assets, and the
// small dashboard.
type RootPanelData struct {
	Folders       []models.Folder
	UnfiledAssets []models.Asset
	UnfiledTotal  int
	Stats         *assets.DashboardStats
}

func (a *App) rootPanelData(ctx context.Context) (*RootPanelData, error) {
	folderList, err := a.Folders.Children(ctx, nil)
	if err != nil {
		return nil, err
	}
	unfiled, total, err := a.Assets.List(ctx, assets.ListFilter{FolderSet: true, FolderID: nil, Page: 1, PageSize: 50})
	if err != nil {
		return nil, err
	}
	stats, err := a.Assets.Stats(ctx)
	if err != nil {
		return nil, err
	}
	return &RootPanelData{Folders: folderList, UnfiledAssets: unfiled, UnfiledTotal: total, Stats: stats}, nil
}

func (a *App) handlePanelRoot(w http.ResponseWriter, r *http.Request) {
	data, err := a.rootPanelData(r.Context())
	if err != nil {
		writeErr(w, http.StatusInternalServerError, err.Error())
		return
	}
	a.RenderFragment(w, http.StatusOK, "panel_root", data)
}

// FolderPanelData backs the main panel when a folder is selected.
type FolderPanelData struct {
	Folder     *models.Folder
	Breadcrumb []models.BreadcrumbItem
	Subfolders []models.Folder
	Assets     []models.Asset
	Total      int
	Page       int
	PageSize   int
	ItemTypes  []models.ItemType
	Statuses   []models.Status
	FilterType int64
	FilterStat int64
	Query      string
}

func (a *App) handlePanelFolder(w http.ResponseWriter, r *http.Request) {
	ctx := r.Context()
	id, err := pathID(r, "id")
	if err != nil {
		writeErr(w, http.StatusBadRequest, "invalid folder id")
		return
	}
	folder, err := a.Folders.Get(ctx, id)
	if err != nil {
		writeErr(w, http.StatusNotFound, err.Error())
		return
	}
	breadcrumb, err := a.Folders.Path(ctx, id)
	if err != nil {
		writeErr(w, http.StatusInternalServerError, err.Error())
		return
	}
	subfolders, err := a.Folders.Children(ctx, &id)
	if err != nil {
		writeErr(w, http.StatusInternalServerError, err.Error())
		return
	}

	page := queryInt(r, "page", 1)
	filterType := queryInt64(r, "item_type_id")
	filterStatus := queryInt64(r, "status_id")
	query := r.URL.Query().Get("q")

	assetList, total, err := a.Assets.List(ctx, assets.ListFilter{
		FolderID: &id, FolderSet: true, ItemTypeID: filterType, StatusID: filterStatus,
		Query: query, Page: page, PageSize: 50,
	})
	if err != nil {
		writeErr(w, http.StatusInternalServerError, err.Error())
		return
	}

	itemTypes, err := a.ItemTypes.List(ctx, false)
	if err != nil {
		writeErr(w, http.StatusInternalServerError, err.Error())
		return
	}
	statusList, err := a.Statuses.List(ctx)
	if err != nil {
		writeErr(w, http.StatusInternalServerError, err.Error())
		return
	}

	a.RenderFragment(w, http.StatusOK, "panel_folder", FolderPanelData{
		Folder: folder, Breadcrumb: breadcrumb, Subfolders: subfolders,
		Assets: assetList, Total: total, Page: page, PageSize: 50,
		ItemTypes: itemTypes, Statuses: statusList,
		FilterType: filterType, FilterStat: filterStatus, Query: query,
	})
}

// AssetPanelData backs the main panel when an asset is selected (view mode).
type AssetPanelData struct {
	Asset         *models.Asset
	CanEdit       bool
	FolderOptions []FolderOption
}

func (a *App) handlePanelAsset(w http.ResponseWriter, r *http.Request) {
	ctx := r.Context()
	id, err := pathID(r, "id")
	if err != nil {
		writeErr(w, http.StatusBadRequest, "invalid asset id")
		return
	}
	asset, err := a.Assets.Get(ctx, id)
	if err != nil {
		writeErr(w, http.StatusNotFound, err.Error())
		return
	}
	opts, err := a.folderOptions(ctx)
	if err != nil {
		writeErr(w, http.StatusInternalServerError, err.Error())
		return
	}
	a.RenderFragment(w, http.StatusOK, "panel_asset", AssetPanelData{Asset: asset, CanEdit: currentUser(r).IsAdmin(), FolderOptions: opts})
}

// AssetFormData backs both the "new asset" and "edit asset" forms.
type AssetFormData struct {
	Asset         *models.Asset // nil when creating
	FolderID      *int64
	ItemTypes     []models.ItemType
	Statuses      []models.Status
	Users         []models.User
	FolderOptions []FolderOption
	SelectedIT    int64
	Fields        []models.AssetFieldValue
}

func (a *App) handlePanelAssetNew(w http.ResponseWriter, r *http.Request) {
	ctx := r.Context()
	folderID, err := queryOptionalID(r, "folder_id")
	if err != nil {
		writeErr(w, http.StatusBadRequest, "invalid folder_id")
		return
	}
	itemTypes, err := a.ItemTypes.List(ctx, false)
	if err != nil {
		writeErr(w, http.StatusInternalServerError, err.Error())
		return
	}
	statusList, err := a.Statuses.List(ctx)
	if err != nil {
		writeErr(w, http.StatusInternalServerError, err.Error())
		return
	}
	userList, err := a.Users.List(ctx)
	if err != nil {
		writeErr(w, http.StatusInternalServerError, err.Error())
		return
	}
	folderOpts, err := a.folderOptions(ctx)
	if err != nil {
		writeErr(w, http.StatusInternalServerError, err.Error())
		return
	}

	var selectedIT int64
	var fields []models.AssetFieldValue
	if len(itemTypes) > 0 {
		selectedIT = itemTypes[0].ID
		fields = fieldValuesForCreate(itemTypes[0].Fields)
	}

	a.RenderFragment(w, http.StatusOK, "asset_form", AssetFormData{
		FolderID: folderID, ItemTypes: itemTypes, Statuses: statusList, Users: userList, FolderOptions: folderOpts,
		SelectedIT: selectedIT, Fields: fields,
	})
}

func (a *App) handlePanelAssetEdit(w http.ResponseWriter, r *http.Request) {
	ctx := r.Context()
	id, err := pathID(r, "id")
	if err != nil {
		writeErr(w, http.StatusBadRequest, "invalid asset id")
		return
	}
	asset, err := a.Assets.Get(ctx, id)
	if err != nil {
		writeErr(w, http.StatusNotFound, err.Error())
		return
	}
	itemTypes, err := a.ItemTypes.List(ctx, true)
	if err != nil {
		writeErr(w, http.StatusInternalServerError, err.Error())
		return
	}
	statusList, err := a.Statuses.List(ctx)
	if err != nil {
		writeErr(w, http.StatusInternalServerError, err.Error())
		return
	}
	userList, err := a.Users.List(ctx)
	if err != nil {
		writeErr(w, http.StatusInternalServerError, err.Error())
		return
	}
	folderOpts, err := a.folderOptions(ctx)
	if err != nil {
		writeErr(w, http.StatusInternalServerError, err.Error())
		return
	}

	a.RenderFragment(w, http.StatusOK, "asset_form", AssetFormData{
		Asset: asset, ItemTypes: itemTypes, Statuses: statusList, Users: userList, FolderOptions: folderOpts,
		SelectedIT: asset.ItemTypeID, Fields: asset.CustomFields,
	})
}

// handleAssetFieldsFragment renders just the dynamic custom-field inputs for
// a chosen item type, used when the item type dropdown changes on the
// "new asset" form.
func (a *App) handleAssetFieldsFragment(w http.ResponseWriter, r *http.Request) {
	ctx := r.Context()
	itemTypeID := queryInt64(r, "item_type_id")
	it, err := a.ItemTypes.Get(ctx, itemTypeID)
	if err != nil {
		writeErr(w, http.StatusNotFound, err.Error())
		return
	}
	a.RenderFragment(w, http.StatusOK, "asset_fields_only", fieldValuesForCreate(it.Fields))
}