/++
  module meta_read_source_files;<BR>
  - open markup files<BR>
  - if master file scan for addional files to import/insert
+/
module sdp.meta.read_source_files;
static template SiSUrawMarkupContent() {
  import
    sdp.meta.rgx;
  import
    sdp.meta,
    sdp.output.paths_source,
    std.file,
    std.path;
  mixin SiSUrgxInit;
  static auto rgx = Rgx();
  string[] _images=[];
  auto _extract_images(S)(S content_block) {
    string[] images_;
    auto _content_block = content_block.to!string;
    if (auto m = _content_block.matchAll(rgx.image)) {
      images_ ~= m.captures[1].to!string;
    }
    return images_;
  }
  auto rawsrc = RawMarkupContent();
  auto SiSUrawMarkupContent(O,Fn)(O _opt_action, Fn fn_src) {
    auto _0_header_1_body_content_2_insert_filelist_tuple =
      rawsrc.sourceContentSplitIntoHeaderAndBody(_opt_action, rawsrc.sourceContent(fn_src), fn_src);
    return _0_header_1_body_content_2_insert_filelist_tuple;
  }
  struct RawMarkupContent {
    final sourceContent(in string fn_src) {
      auto raw = MarkupRawUnit();
      auto source_txt_str =
        raw.markupSourceReadIn(fn_src);
      return source_txt_str;
    }
    final auto sourceContentSplitIntoHeaderAndBody(O)(O _opt_action, in string source_txt_str, in string fn_src="") {
      auto raw = MarkupRawUnit();
      string[] insert_file_list;
      string[] images_list;
      auto t =
        raw.markupSourceHeaderContentRawLineTupleArray(source_txt_str);
      auto header_raw = t[0];
      auto sourcefile_body_content = t[1];
      if (fn_src.match(rgx.src_fn_master)) { // filename with path needed if master file (.ssm) not otherwise
        auto ins = Inserts();
        auto tu =
          ins.scan_master_src_for_insert_files_and_import_content(_opt_action, sourcefile_body_content, fn_src);
        static assert(!isTypeTuple!(tu));
        sourcefile_body_content = tu[0];
        insert_file_list = tu[1].dup;
        images_list = tu[2].dup;
      } else if (_opt_action.source || _opt_action.sisupod) {
        auto ins = Inserts();
        auto tu =
          ins.scan_master_src_for_insert_files_and_import_content(_opt_action, sourcefile_body_content, fn_src);
        static assert(!isTypeTuple!(tu));
        images_list = tu[2].dup;
      }
      t = tuple(
        header_raw,
        sourcefile_body_content,
        insert_file_list,
        images_list
      );
      static assert(t.length==4);
      return t;
    }
  }
  struct MarkupRawUnit {
    import std.file;
    final private string readInMarkupSource(in char[] fn_src) {
      enforce(
        exists(fn_src)!=0,
        "file not found: «" ~
        fn_src ~ "»"
      );
      string source_txt_str;
      try {
        if (exists(fn_src)) {
          source_txt_str = fn_src.readText;
        }
      }
      catch (ErrnoException ex) {
      }
      catch (UTFException ex) {
        // Handle validation errors
      }
      catch (FileException ex) {
        // Handle errors
      }
      std.utf.validate(source_txt_str);
      return source_txt_str;
    }
    final private char[][] header0Content1(in string src_text) {
      /+ split string on _first_ match of "^:?A~\s" into [header, content] array/tuple +/
      char[][] header_and_content;
      auto m = (cast(char[]) src_text).matchFirst(rgx.heading_a);
      header_and_content ~= m.pre;
      header_and_content ~= m.hit ~ m.post;
      assert(header_and_content.length == 2,
        "document markup is broken, header body split == "
        ~ header_and_content.length.to!string
        ~ "; (header / body array split should == 2 (split is on level A~))"
      );
      return header_and_content;
    }
    final private char[][] markupSourceLineArray(in char[] src_text) {
      char[][] source_line_arr =
        (cast(char[]) src_text).split(rgx.newline_eol_strip_preceding);
      return source_line_arr;
    }
    auto markupSourceReadIn(in string fn_src) {
      static auto rgx = Rgx();
      enforce(
        fn_src.match(rgx.src_pth),
        "not a sisu markup filename: «" ~
        fn_src ~ "»"
      );
      auto source_txt_str = readInMarkupSource(fn_src);
      return source_txt_str;
    }
    auto markupSourceHeaderContentRawLineTupleArray(in string source_txt_str) {
      string[] file_insert_list = [];
      string[] images_list = [];
      auto hc = header0Content1(source_txt_str);
      auto header = hc[0];
      char[] source_txt = hc[1];
      auto source_line_arr = markupSourceLineArray(source_txt);
      auto t = tuple(
        header,
        source_line_arr,
        file_insert_list,
        images_list
      );
      return t;
    }
    final char[][] getInsertMarkupSourceContentRawLineArray(
      in char[]    fn_src_insert,
      Regex!(char) rgx_file
    ) {
      enforce(
        fn_src_insert.match(rgx_file),
        "not a sisu markup filename: «" ~
        fn_src_insert  ~ "»"
      );
      auto source_txt_str = readInMarkupSource(fn_src_insert);
      auto source_line_arr = markupSourceLineArray(source_txt_str);
      return source_line_arr;
    }
  }
  struct Inserts {
    import sdp.meta.defaults;
    auto scan_subdoc_source(O)(
      O        _opt_action,
      char[][] markup_sourcefile_insert_content,
      string   fn_src
    ) {
      mixin SiSUrgxInitFlags;
      char[][] contents_insert;
      auto type1 = flags_type_init;
      auto fn_pth_full = fn_src.match(rgx.src_pth);
      auto markup_src_file_path = fn_pth_full.captures[1];
      foreach (line; markup_sourcefile_insert_content) {
        if (type1["curly_code"] == 1) {
          type1["header_make"] = 0;
          type1["header_meta"] = 0;
          if (line.matchFirst(rgx.block_curly_code_close)) {
            type1["curly_code"] = 0;
          }
          contents_insert ~= line;
        } else if (line.matchFirst(rgx.block_curly_code_open)) {
          type1["curly_code"] = 1;
          type1["header_make"] = 0;
          type1["header_meta"] = 0;
          contents_insert ~= line;
        } else if (type1["tic_code"] == 1) {
          type1["header_make"] = 0;
          type1["header_meta"] = 0;
          if (line.matchFirst(rgx.block_tic_close)) {
            type1["tic_code"] = 0;
          }
          contents_insert ~= line;
        } else if (line.matchFirst(rgx.block_tic_code_open)) {
          type1["tic_code"] = 1;
          type1["header_make"] = 0;
          type1["header_meta"] = 0;
          contents_insert ~= line;
        } else if (
          (type1["header_make"] == 1)
          && line.matchFirst(rgx.native_header_sub)
        ) {
            type1["header_make"] = 1;
            type1["header_meta"] = 0;
        } else if (
          (type1["header_meta"] == 1)
          && line.matchFirst(rgx.native_header_sub)
        ) {
            type1["header_meta"] = 1;
            type1["header_make"] = 0;
        } else if (auto m = line.match(rgx.insert_src_fn_ssi_or_sst)) {
          type1["header_make"] = 0;
          type1["header_meta"] = 0;
          auto insert_fn = m.captures[2];
          auto insert_sub_pth = m.captures[1];
          auto fn_src_insert =
            chainPath(markup_src_file_path, insert_sub_pth ~ insert_fn).array;
          auto raw = MarkupRawUnit();
          auto markup_sourcesubfile_insert_content =
            raw.getInsertMarkupSourceContentRawLineArray(fn_src_insert, rgx.src_fn_find_inserts);
          debug(insert_file) {
            tell_l("red", line);
            tell_l("red", fn_src_insert);
            tell_l("fuchsia", "ERROR");
            writeln(
              "  length contents insert array: ",
              markup_sourcesubfile_insert_content.length
            );
          }
          if (_opt_action.source || _opt_action.sisupod) {
            _images ~= _extract_images(markup_sourcesubfile_insert_content);
          }
          auto ins = Inserts();
          /+
            - 1. load file
            - 2. read lines
            - 3. scan lines
              - a. if filename insert, and insert filename
                 - repeat 1
              - b. else
                 - add line to new array;
                 - build image list, search for any image files to add to image list
          +/
        } else {
          type1["header_make"] = 0;
          type1["header_meta"] = 0;
          contents_insert ~= line; // images to extract for image list?
          if (_opt_action.source || _opt_action.sisupod) {
            auto _image_linelist = _extract_images(line);
            if (_image_linelist.length > 0) {
              _images ~= _image_linelist;
            }
          }
        }
      } // end src subdoc (inserts) loop
      auto t = tuple(
        contents_insert,
        _images
      );
      return t;
    }
    auto scan_master_src_for_insert_files_and_import_content(O)(
      O        _opt_action,
      char[][] sourcefile_body_content,
      string   fn_src
    ) {
      import std.algorithm;
      mixin SiSUrgxInitFlags;
      char[][] contents;
      auto type = flags_type_init;
      auto fn_pth_full = fn_src.match(rgx.src_pth);
      auto markup_src_file_path = fn_pth_full.captures[1];
      char[][] contents_insert;
      string[] _images =[];
      string[] insert_file_list =[];
      foreach (line; sourcefile_body_content) {
        if (type["curly_code"] == 1) {
          if (line.matchFirst(rgx.block_curly_code_close)) {
            type["curly_code"] = 0;
          }
          contents ~= line;
        } else if (line.matchFirst(rgx.block_curly_code_open)) {
          type["curly_code"] = 1;
          contents ~= line;
        } else if (type["tic_code"] == 1) {
          if (line.matchFirst(rgx.block_tic_close)) {
            type["tic_code"] = 0;
          }
          contents ~= line;
        } else if (line.matchFirst(rgx.block_tic_code_open)) {
          type["tic_code"] = 1;
          contents ~= line;
        } else if (auto m = line.match(rgx.insert_src_fn_ssi_or_sst)) {
          auto insert_fn = m.captures[2];
          auto insert_sub_pth = m.captures[1];
          auto fn_src_insert =
            chainPath(markup_src_file_path, insert_sub_pth ~ insert_fn).array;
            insert_file_list ~= to!string(fn_src_insert);
          auto raw = MarkupRawUnit();
          /+ TODO +/
          if (auto ma = line.match(rgx.src_fn_text)) {
            /+ .sst when inserted, not used: headers and heading level ^:?A~ so remove +/
            writeln(__LINE__); writeln(ma);
          }
          auto markup_sourcefile_insert_content =
            raw.getInsertMarkupSourceContentRawLineArray(fn_src_insert, rgx.src_fn_find_inserts);
          debug(insert_file) {
            tell_l("red", line);
            tell_l("red", fn_src_insert);
            writeln(
              "  length contents insert array: ",
              markup_sourcefile_insert_content.length
            );
          }
          auto ins = Inserts();
          auto contents_insert_tu = ins.scan_subdoc_source(
            _opt_action,
            markup_sourcefile_insert_content,
            to!string(fn_src_insert)
          );
          contents ~= contents_insert_tu[0]; // images to extract for image list?
          if (_opt_action.source || _opt_action.sisupod) {
            auto _image_linelist = _extract_images(contents_insert_tu[0]);
            if (_image_linelist.length > 0) {
              _images ~= _image_linelist;
            }
          }
          /+
            - 1. load file
            - 2. read lines
            - 3. scan lines
              - a. if filename insert, and insert filename
                 - repeat 1
              - b. else
                 - add line to new array;
                 - build image list, search for any image files to add to image list
          +/
        } else {
          contents ~= line;
          if (_opt_action.source || _opt_action.sisupod) {
            auto _image_linelist = _extract_images(line);
            if (_image_linelist.length > 0) {
              _images ~= _image_linelist;
            }
          }
        }
      } // end src doc loop
      string[] images = [];
      foreach(i; uniq(_images.sort())) {
        images ~= i;
      }
      debug(insert_file) {
        writeln(__LINE__);
        writeln(contents.length);
      }
      auto t = tuple(
        contents,
        insert_file_list,
        images
      );
      return t;
    }
  }
}