// Copyright 2013 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include "components/dom_distiller/content/distiller_page_web_contents.h"

#include "base/callback.h"
#include "base/memory/scoped_ptr.h"
#include "base/strings/utf_string_conversions.h"
#include "components/dom_distiller/content/web_contents_main_frame_observer.h"
#include "components/dom_distiller/core/distiller_page.h"
#include "components/dom_distiller/core/dom_distiller_service.h"
#include "content/public/browser/browser_context.h"
#include "content/public/browser/navigation_controller.h"
#include "content/public/browser/render_frame_host.h"
#include "content/public/browser/render_view_host.h"
#include "content/public/browser/web_contents.h"
#include "content/public/browser/web_contents_observer.h"
#include "url/gurl.h"

namespace dom_distiller {

SourcePageHandleWebContents::SourcePageHandleWebContents(
    scoped_ptr<content::WebContents> web_contents)
    : web_contents_(web_contents.Pass()) {
  DCHECK(web_contents_);
}

SourcePageHandleWebContents::~SourcePageHandleWebContents() {
}

scoped_ptr<content::WebContents> SourcePageHandleWebContents::GetWebContents() {
  return web_contents_.Pass();
}

scoped_ptr<DistillerPage> DistillerPageWebContentsFactory::CreateDistillerPage()
    const {
  DCHECK(browser_context_);
  return scoped_ptr<DistillerPage>(new DistillerPageWebContents(
      browser_context_, scoped_ptr<SourcePageHandleWebContents>()));
}

scoped_ptr<DistillerPage>
DistillerPageWebContentsFactory::CreateDistillerPageWithHandle(
    scoped_ptr<SourcePageHandle> handle) const {
  DCHECK(browser_context_);
  scoped_ptr<SourcePageHandleWebContents> web_contents_handle =
      scoped_ptr<SourcePageHandleWebContents>(
          static_cast<SourcePageHandleWebContents*>(handle.release()));
  return scoped_ptr<DistillerPage>(new DistillerPageWebContents(
      browser_context_, web_contents_handle.Pass()));
}

DistillerPageWebContents::DistillerPageWebContents(
    content::BrowserContext* browser_context,
    scoped_ptr<SourcePageHandleWebContents> optional_web_contents_handle)
    : state_(IDLE), browser_context_(browser_context) {
  if (optional_web_contents_handle) {
    web_contents_ = optional_web_contents_handle->GetWebContents().Pass();
  }
}

DistillerPageWebContents::~DistillerPageWebContents() {
}

void DistillerPageWebContents::DistillPageImpl(const GURL& url,
                                               const std::string& script) {
  DCHECK(browser_context_);
  DCHECK(state_ == IDLE);
  state_ = LOADING_PAGE;
  script_ = script;

  if (web_contents_ && web_contents_->GetLastCommittedURL() == url) {
    WebContentsMainFrameObserver* main_frame_observer =
        WebContentsMainFrameObserver::FromWebContents(web_contents_.get());
    if (main_frame_observer && main_frame_observer->is_initialized()) {
      if (main_frame_observer->is_document_loaded_in_main_frame()) {
        // Main frame has already loaded for the current WebContents, so execute
        // JavaScript immediately.
        ExecuteJavaScript();
      } else {
        // Main frame document has not loaded yet, so wait until it has before
        // executing JavaScript. It will trigger after DocumentLoadedInFrame is
        // called for the main frame.
        content::WebContentsObserver::Observe(web_contents_.get());
      }
    } else {
      // The WebContentsMainFrameObserver has not been correctly initialized,
      // so fall back to creating a new WebContents.
      CreateNewWebContents(url);
    }
  } else {
    CreateNewWebContents(url);
  }
}

void DistillerPageWebContents::CreateNewWebContents(const GURL& url) {
  // Create new WebContents to use for distilling the content.
  content::WebContents::CreateParams create_params(browser_context_);
  create_params.initially_hidden = true;
  web_contents_.reset(content::WebContents::Create(create_params));
  DCHECK(web_contents_.get());

  // Start observing WebContents and load the requested URL.
  content::WebContentsObserver::Observe(web_contents_.get());
  content::NavigationController::LoadURLParams params(url);
  web_contents_->GetController().LoadURLWithParams(params);
}

void DistillerPageWebContents::DocumentLoadedInFrame(
    int64 frame_id,
    RenderViewHost* render_view_host) {
  if (frame_id == web_contents_->GetMainFrame()->GetRoutingID()) {
    ExecuteJavaScript();
  }
}

void DistillerPageWebContents::DidFailLoad(
    int64 frame_id,
    const GURL& validated_url,
    bool is_main_frame,
    int error_code,
    const base::string16& error_description,
    RenderViewHost* render_view_host) {
  if (is_main_frame) {
    content::WebContentsObserver::Observe(NULL);
    DCHECK(state_ == LOADING_PAGE || state_ == EXECUTING_JAVASCRIPT);
    state_ = PAGELOAD_FAILED;
    scoped_ptr<base::Value> empty(base::Value::CreateNullValue());
    OnWebContentsDistillationDone(GURL(), empty.get());
  }
}

void DistillerPageWebContents::ExecuteJavaScript() {
  content::RenderFrameHost* frame = web_contents_->GetMainFrame();
  DCHECK(frame);
  DCHECK_EQ(LOADING_PAGE, state_);
  state_ = EXECUTING_JAVASCRIPT;
  content::WebContentsObserver::Observe(NULL);
  web_contents_->Stop();
  DVLOG(1) << "Beginning distillation";
  frame->ExecuteJavaScript(
      base::UTF8ToUTF16(script_),
      base::Bind(&DistillerPageWebContents::OnWebContentsDistillationDone,
                 base::Unretained(this),
                 web_contents_->GetLastCommittedURL()));
}

void DistillerPageWebContents::OnWebContentsDistillationDone(
    const GURL& page_url,
    const base::Value* value) {
  DCHECK(state_ == PAGELOAD_FAILED || state_ == EXECUTING_JAVASCRIPT);
  state_ = IDLE;
  DistillerPage::OnDistillationDone(page_url, value);
}

}  // namespace dom_distiller