package otbuiltin

import (
	"strings"
	"unsafe"

	glib "github.com/sjoerdsimons/ostree-go/pkg/glibobject"
)

// #cgo pkg-config: ostree-1
// #include <stdlib.h>
// #include <glib.h>
// #include <ostree.h>
// #include "builtin.go.h"
import "C"

// Global variable for options
var checkoutOpts checkoutOptions

// Contains all of the options for checking commits out of
// an ostree repo
type checkoutOptions struct {
	UserMode         bool   // Do not change file ownership or initialize extended attributes
	Union            bool   // Keep existing directories and unchanged files, overwriting existing filesystem
	AllowNoent       bool   // Do nothing if the specified filepath does not exist
	DisableCache     bool   // Do not update or use the internal repository uncompressed object caceh
	Whiteouts        bool   // Process 'whiteout' (docker style) entries
	RequireHardlinks bool   // Do not fall back to full copies if hard linking fails
	Subpath          string // Checkout sub-directory path
	FromFile         string // Process many checkouts from the given file
}

// Instantiates and returns a checkoutOptions struct with default values set
func NewCheckoutOptions() checkoutOptions {
	return checkoutOptions{}
}

// Checks out a commit with the given ref from a repository at the location of repo path to to the destination.  Returns an error if the checkout could not be processed
func Checkout(repoPath, destination, commit string, opts checkoutOptions) error {
	checkoutOpts = opts

	var cancellable *glib.GCancellable
	ccommit := C.CString(commit)
	defer C.free(unsafe.Pointer(ccommit))
	var gerr = glib.NewGError()
	cerr := (*C.GError)(gerr.Ptr())
	defer C.free(unsafe.Pointer(cerr))

	repoPathc := C.g_file_new_for_path(C.CString(repoPath))
	defer C.g_object_unref(C.gpointer(repoPathc))
	crepo := C.ostree_repo_new(repoPathc)
	if !glib.GoBool(glib.GBoolean(C.ostree_repo_open(crepo, (*C.GCancellable)(cancellable.Ptr()), &cerr))) {
		return generateError(cerr)
	}

	if strings.Compare(checkoutOpts.FromFile, "") != 0 {
		err := processManyCheckouts(crepo, destination, cancellable)
		if err != nil {
			return err
		}
	} else {
		var resolvedCommit *C.char
		defer C.free(unsafe.Pointer(resolvedCommit))
		if !glib.GoBool(glib.GBoolean(C.ostree_repo_resolve_rev(crepo, ccommit, C.FALSE, &resolvedCommit, &cerr))) {
			return generateError(cerr)
		}
		err := processOneCheckout(crepo, resolvedCommit, checkoutOpts.Subpath, destination, cancellable)
		if err != nil {
			return err
		}
	}
	return nil
}

// Processes one checkout from the repo
func processOneCheckout(crepo *C.OstreeRepo, resolvedCommit *C.char, subpath, destination string, cancellable *glib.GCancellable) error {
	cdest := C.CString(destination)
	defer C.free(unsafe.Pointer(cdest))
	var gerr = glib.NewGError()
	cerr := (*C.GError)(gerr.Ptr())
	defer C.free(unsafe.Pointer(cerr))
	var repoCheckoutAtOptions C.OstreeRepoCheckoutAtOptions

	if checkoutOpts.UserMode {
		repoCheckoutAtOptions.mode = C.OSTREE_REPO_CHECKOUT_MODE_USER
	}
	if checkoutOpts.Union {
		repoCheckoutAtOptions.overwrite_mode = C.OSTREE_REPO_CHECKOUT_OVERWRITE_UNION_FILES
	}

	checkedOut := glib.GoBool(glib.GBoolean(C.ostree_repo_checkout_at(crepo, &repoCheckoutAtOptions, C._at_fdcwd(), cdest, resolvedCommit, nil, &cerr)))
	if !checkedOut {
		return generateError(cerr)
	}

	return nil
}

// process many checkouts
func processManyCheckouts(crepo *C.OstreeRepo, target string, cancellable *glib.GCancellable) error {
	return nil
}