/* See LICENSE file for license and copyright information */

#define _BSD_SOURCE
#define _XOPEN_SOURCE 700
// TODO: Implement realpath

#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <limits.h>
#include <errno.h>
#include <glib.h>
#include <glib/gi18n.h>

#include <girara/datastructures.h>
#include <girara/utils.h>
#include <girara/statusbar.h>
#include <girara/session.h>
#include <girara/settings.h>

#include "document.h"
#include "utils.h"
#include "zathura.h"
#include "render.h"
#include "database.h"
#include "page.h"
#include "page-widget.h"
#include "plugin.h"

/** Read a most GT_MAX_READ bytes before falling back to file. */
static const size_t GT_MAX_READ = 1 << 16;

static const gchar* guess_type(const char* path);

zathura_document_t*
zathura_document_open(zathura_t* zathura, const char* path, const char* password)
{
  if (path == NULL) {
    return NULL;
  }

  if (g_file_test(path, G_FILE_TEST_EXISTS) == FALSE) {
    girara_error("File '%s' does not exist", path);
    return NULL;
  }

  const gchar* content_type = guess_type(path);
  if (content_type == NULL) {
    girara_error("Could not determine file type.");
    return NULL;
  }

  /* determine real path */
  long path_max;
#ifdef PATH_MAX
  path_max = PATH_MAX;
#else
  path_max = pathconf(path,_PC_PATH_MAX);
  if (path_max <= 0)
    path_max = 4096;
#endif

  char* real_path              = NULL;
  zathura_document_t* document = NULL;

  real_path = malloc(sizeof(char) * path_max);
  if (real_path == NULL) {
    g_free((void*)content_type);
    return NULL;
  }

  if (realpath(path, real_path) == NULL) {
    g_free((void*)content_type);
    free(real_path);
    return NULL;
  }

  zathura_plugin_t* plugin = NULL;
  GIRARA_LIST_FOREACH(zathura->plugins.type_plugin_mapping, zathura_type_plugin_mapping_t*, iter, mapping)
    if (g_content_type_equals(content_type, mapping->type)) {
      plugin = mapping->plugin;
      break;
    }
  GIRARA_LIST_FOREACH_END(zathura->plugins.type_plugin_mapping, zathura_type_plugin_mapping_t*, iter, mapping);
  g_free((void*)content_type);

  if (plugin == NULL) {
    girara_error("unknown file type\n");
    goto error_free;
  }

  document = g_malloc0(sizeof(zathura_document_t));

  document->file_path = real_path;
  document->password  = password;
  document->scale     = 1.0;
  document->zathura   = zathura;
  document->plugin    = plugin;

  /* open document */
  if (plugin->functions.document_open == NULL) {
    girara_error("plugin has no open function\n");
    goto error_free;
  }

  zathura_error_t error = plugin->functions.document_open(document);
  if (error != ZATHURA_ERROR_OK) {
    if (error == ZATHURA_ERROR_INVALID_PASSWORD) {
      zathura_password_dialog_info_t* password_dialog_info = malloc(sizeof(zathura_password_dialog_info_t));
      if (password_dialog_info != NULL) {
        password_dialog_info->path    = g_strdup(path);
        password_dialog_info->zathura = zathura;

        if (path != NULL) {
          girara_dialog(zathura->ui.session, "Enter password:", true, NULL,
              (girara_callback_inputbar_activate_t) cb_password_dialog, password_dialog_info);
          goto error_free;
        } else {
          free(password_dialog_info);
        }
      }
      goto error_free;
    }

    girara_error("could not open document\n");
    goto error_free;
  }

  /* read history file */
  zathura_db_get_fileinfo(zathura->database, document->file_path,
      &document->current_page_number, &document->page_offset, &document->scale,
      &document->rotate);

  /* check for valid scale value */
  if (document->scale <= FLT_EPSILON) {
    girara_warning("document info: '%s' has non positive scale", document->file_path);
    document->scale = 1;
  }

  /* check current page number */
  if (document->current_page_number > document->number_of_pages) {
    girara_warning("document info: '%s' has an invalid page number", document->file_path);
    document->current_page_number = 0;
  }

  /* update statusbar */
  girara_statusbar_item_set_text(zathura->ui.session, zathura->ui.statusbar.file, real_path);

  /* read all pages */
  document->pages = calloc(document->number_of_pages, sizeof(zathura_page_t*));
  if (document->pages == NULL) {
    goto error_free;
  }

  for (unsigned int page_id = 0; page_id < document->number_of_pages; page_id++) {
    zathura_page_t* page = zathura_page_new(document, page_id, NULL);
    if (page == NULL) {
      goto error_free;
    }

    document->pages[page_id] = page;
  }

  /* jump to first page if setting enabled */
  bool always_first_page = false;
  girara_setting_get(zathura->ui.session, "open-first-page", &always_first_page);
  if (always_first_page == true) {
    document->current_page_number = 0;
  }

  /* apply open adjustment */
  char* adjust_open = "best-fit";
  document->adjust_mode = ADJUST_BESTFIT;
  if (girara_setting_get(zathura->ui.session, "adjust-open", &(adjust_open)) == true) {
    if (g_strcmp0(adjust_open, "best-fit") == 0) {
      document->adjust_mode = ADJUST_BESTFIT;
    } else if (g_strcmp0(adjust_open, "width") == 0) {
      document->adjust_mode = ADJUST_WIDTH;
    } else {
      document->adjust_mode = ADJUST_NONE;
    }
    g_free(adjust_open);
  }

  return document;

error_free:

  free(real_path);

  if (document != NULL && document->pages != NULL) {
    for (unsigned int page_id = 0; page_id < document->number_of_pages; page_id++) {
      zathura_page_free(document->pages[page_id]);
    }

    free(document->pages);
  }

  g_free(document);
  return NULL;
}

zathura_error_t
zathura_document_free(zathura_document_t* document)
{
  if (document == NULL || document->plugin == NULL || document->zathura == NULL
      || document->zathura->ui.session == NULL) {
    return ZATHURA_ERROR_INVALID_ARGUMENTS;
  }

  /* free pages */
  for (unsigned int page_id = 0; page_id < document->number_of_pages; page_id++) {
    zathura_page_free(document->pages[page_id]);
    document->pages[page_id] = NULL;
  }

  free(document->pages);

  /* free document */
  zathura_error_t error = ZATHURA_ERROR_OK;
  if (document->plugin->functions.document_free == NULL) {
    girara_notify(document->zathura->ui.session, GIRARA_WARNING, _("%s not implemented"), __FUNCTION__);
    girara_error("%s not implemented", __FUNCTION__);
    error = ZATHURA_ERROR_NOT_IMPLEMENTED;
  } else {
    error = document->plugin->functions.document_free(document, document->data);
  }

  if (document->file_path != NULL) {
    free(document->file_path);
  }

  g_free(document);

  return error;
}

const char*
zathura_document_get_path(zathura_document_t* document)
{
  if (document == NULL) {
    return NULL;
  }

  return document->file_path;
}

const char*
zathura_document_get_password(zathura_document_t* document)
{
  if (document == NULL) {
    return NULL;
  }

  return document->password;
}

void*
zathura_document_get_data(zathura_document_t* document)
{
  if (document == NULL) {
    return NULL;
  }

  return document->data;
}

void
zathura_document_set_data(zathura_document_t* document, void* data)
{
  if (document == NULL) {
    return;
  }

  document->data = data;
}

unsigned int
zathura_document_get_number_of_pages(zathura_document_t* document)
{
  if (document == NULL) {
    return 0;
  }

  return document->number_of_pages;
}

void
zathura_document_set_number_of_pages(zathura_document_t* document, unsigned int number_of_pages)
{
  if (document == NULL) {
    return;
  }

  document->number_of_pages = number_of_pages;
}

unsigned int
zathura_document_get_current_page(zathura_document_t* document)
{
  if (document == NULL) {
    return 0;
  }

  return document->current_page_number;
}

void
zathura_document_set_current_page(zathura_document_t* document, unsigned int
    current_page)
{
  if (document == NULL) {
    return;
  }

  document->current_page_number = current_page;
}

zathura_error_t
zathura_document_save_as(zathura_document_t* document, const char* path)
{
  if (document == NULL || document->plugin == NULL || path == NULL ||
      document->zathura == NULL || document->zathura->ui.session == NULL) {
    return ZATHURA_ERROR_UNKNOWN;
  }

  if (document->plugin->functions.document_save_as == NULL) {
    girara_notify(document->zathura->ui.session, GIRARA_WARNING, _("%s not implemented"), __FUNCTION__);
    girara_error("%s not implemented", __FUNCTION__);
    return ZATHURA_ERROR_NOT_IMPLEMENTED;
  }

  return document->plugin->functions.document_save_as(document, document->data, path);
}

girara_tree_node_t*
zathura_document_index_generate(zathura_document_t* document, zathura_error_t* error)
{
  if (document == NULL || document->plugin == NULL || document->zathura == NULL
      || document->zathura->ui.session == NULL) {
    if (error != NULL) {
      *error = ZATHURA_ERROR_INVALID_ARGUMENTS;
    }
    return NULL;
  }

  if (document->plugin->functions.document_index_generate == NULL) {
    girara_notify(document->zathura->ui.session, GIRARA_WARNING, _("%s not implemented"), __FUNCTION__);
    girara_error("%s not implemented", __FUNCTION__);
    if (error != NULL) {
      *error = ZATHURA_ERROR_NOT_IMPLEMENTED;
    }
    return NULL;
  }

  return document->plugin->functions.document_index_generate(document, document->data, error);
}

girara_list_t*
zathura_document_attachments_get(zathura_document_t* document, zathura_error_t* error)
{
  if (document == NULL || document->plugin == NULL || document->zathura == NULL
      || document->zathura->ui.session == NULL) {
    if (error != NULL) {
      *error = ZATHURA_ERROR_INVALID_ARGUMENTS;
    }
    return NULL;
  }

  if (document->plugin->functions.document_attachments_get == NULL) {
    girara_notify(document->zathura->ui.session, GIRARA_WARNING, _("%s not implemented"), __FUNCTION__);
    girara_error("%s not implemented", __FUNCTION__);
    if (error != NULL) {
      *error = ZATHURA_ERROR_NOT_IMPLEMENTED;
    }
    return NULL;
  }

  return document->plugin->functions.document_attachments_get(document, document->data, error);
}

zathura_error_t
zathura_document_attachment_save(zathura_document_t* document, const char* attachment, const char* file)
{
  if (document == NULL || document->plugin == NULL || document->zathura == NULL
      || document->zathura->ui.session == NULL) {
    return ZATHURA_ERROR_INVALID_ARGUMENTS;
  }

  if (document->plugin->functions.document_attachment_save == NULL) {
    girara_notify(document->zathura->ui.session, GIRARA_WARNING, _("%s not implemented"), __FUNCTION__);
    girara_error("%s not implemented", __FUNCTION__);
    return ZATHURA_ERROR_NOT_IMPLEMENTED;
  }

  return document->plugin->functions.document_attachment_save(document, document->data, attachment, file);
}

char*
zathura_document_meta_get(zathura_document_t* document, zathura_document_meta_t meta, zathura_error_t* error)
{
  if (document == NULL || document->plugin == NULL || document->zathura == NULL || document->zathura->ui.session == NULL) {
    if (error != NULL) {
      *error = ZATHURA_ERROR_INVALID_ARGUMENTS;
    }
    return NULL;
  }

  if (document->plugin->functions.document_meta_get == NULL) {
    if (error != NULL) {
      *error = ZATHURA_ERROR_NOT_IMPLEMENTED;
    }
    girara_notify(document->zathura->ui.session, GIRARA_WARNING, _("%s not implemented"), __FUNCTION__);
    girara_error("%s not implemented", __FUNCTION__);
    return NULL;
  }

  return document->plugin->functions.document_meta_get(document, document->data, meta, error);
}

static const gchar*
guess_type(const char* path)
{
  gboolean uncertain;
  const gchar* content_type = g_content_type_guess(path, NULL, 0, &uncertain);
  if (content_type == NULL) {
    return NULL;
  }

  if (uncertain == FALSE) {
    return content_type;
  }

  girara_debug("g_content_type is uncertain, guess: %s\n", content_type);

  FILE* f = fopen(path, "rb");
  if (f == NULL) {
    return NULL;
  }

  const int fd = fileno(f);
  guchar* content = NULL;
  size_t length = 0u;
  while (uncertain == TRUE && length < GT_MAX_READ) {
    g_free((void*)content_type);
    content_type = NULL;

    content = g_realloc(content, length + BUFSIZ);
    const ssize_t r = read(fd, content + length, BUFSIZ);
    if (r == -1) {
      break;
    }

    length += r;
    content_type = g_content_type_guess(NULL, content, length, &uncertain);
    girara_debug("new guess: %s uncertain: %d, read: %zu\n", content_type, uncertain, length);
  }

  fclose(f);
  g_free(content);
  if (uncertain == FALSE) {
    return content_type;
  }

  g_free((void*)content_type);
  content_type = NULL;

  girara_debug("falling back to file");

  GString* command = g_string_new("file -b --mime-type ");
  char* tmp        = g_shell_quote(path);

  g_string_append(command, tmp);
  g_free(tmp);

  GError* error = NULL;
  char* out = NULL;
  int ret = 0;
  g_spawn_command_line_sync(command->str, &out, NULL, &ret, &error);
  g_string_free(command, TRUE);
  if (error != NULL) {
    girara_warning("failed to execute command: %s", error->message);
    g_error_free(error);
    g_free(out);
    return NULL;
  }
  if (WEXITSTATUS(ret) != 0) {
    girara_warning("file failed with error code: %d", WEXITSTATUS(ret));
    g_free(out);
    return NULL;
  }

  g_strdelimit(out, "\n\r", '\0');
  return out;
}