/* This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at https://mozilla.org/MPL/2.0/. */

use crate::dom::bindings::codegen::Bindings::BlobBinding::BlobMethods;
use crate::dom::bindings::codegen::Bindings::FileReaderSyncBinding::FileReaderSyncMethods;
use crate::dom::bindings::error::{Error, Fallible};
use crate::dom::bindings::reflector::{reflect_dom_object, Reflector};
use crate::dom::bindings::root::DomRoot;
use crate::dom::bindings::str::DOMString;
use crate::dom::blob::Blob;
use crate::dom::filereader::FileReaderSharedFunctionality;
use crate::dom::globalscope::GlobalScope;
use crate::script_runtime::JSContext;
use dom_struct::dom_struct;
use js::jsapi::JSObject;
use js::typedarray::{ArrayBuffer, CreateWith};
use std::ptr;
use std::ptr::NonNull;

#[dom_struct]
pub struct FileReaderSync {
    reflector: Reflector,
}

impl FileReaderSync {
    pub fn new_inherited() -> FileReaderSync {
        FileReaderSync {
            reflector: Reflector::new(),
        }
    }

    pub fn new(global: &GlobalScope) -> DomRoot<FileReaderSync> {
        reflect_dom_object(Box::new(FileReaderSync::new_inherited()), global)
    }

    #[allow(non_snake_case)]
    pub fn Constructor(global: &GlobalScope) -> Fallible<DomRoot<FileReaderSync>> {
        Ok(FileReaderSync::new(global))
    }

    fn get_blob_bytes(blob: &Blob) -> Result<Vec<u8>, Error> {
        blob.get_bytes().map_err(|_| Error::NotReadable)
    }
}

impl FileReaderSyncMethods for FileReaderSync {
    // https://w3c.github.io/FileAPI/#readAsBinaryStringSyncSection
    fn ReadAsBinaryString(&self, blob: &Blob) -> Fallible<DOMString> {
        // step 1
        let blob_contents = FileReaderSync::get_blob_bytes(blob)?;

        // step 2
        Ok(DOMString::from(String::from_utf8_lossy(&blob_contents)))
    }

    // https://w3c.github.io/FileAPI/#readAsTextSync
    fn ReadAsText(&self, blob: &Blob, label: Option<DOMString>) -> Fallible<DOMString> {
        // step 1
        let blob_contents = FileReaderSync::get_blob_bytes(blob)?;

        // step 2
        let blob_label = label.map(String::from);
        let blob_type = String::from(blob.Type());

        let output =
            FileReaderSharedFunctionality::text_decode(&blob_contents, &blob_type, &blob_label);

        Ok(output)
    }

    // https://w3c.github.io/FileAPI/#readAsDataURLSync-section
    fn ReadAsDataURL(&self, blob: &Blob) -> Fallible<DOMString> {
        // step 1
        let blob_contents = FileReaderSync::get_blob_bytes(blob)?;

        // step 2
        let output =
            FileReaderSharedFunctionality::dataurl_format(&blob_contents, blob.Type().to_string());

        Ok(output)
    }

    #[allow(unsafe_code)]
    // https://w3c.github.io/FileAPI/#readAsArrayBufferSyncSection
    fn ReadAsArrayBuffer(&self, cx: JSContext, blob: &Blob) -> Fallible<NonNull<JSObject>> {
        // step 1
        let blob_contents = FileReaderSync::get_blob_bytes(blob)?;

        // step 2
        unsafe {
            rooted!(in(*cx) let mut array_buffer = ptr::null_mut::<JSObject>());
            assert!(ArrayBuffer::create(
                *cx,
                CreateWith::Slice(&blob_contents),
                array_buffer.handle_mut()
            )
            .is_ok());

            Ok(NonNull::new_unchecked(array_buffer.get()))
        }
    }
}