(* -*- mode: tuareg; -*- *)

open Dream_html
open Config

type body_data = {
  title : string;
  subtitle : string;
  topnav : Dream_html.node;
  content : Dream_html.node list;
}

module Components = struct
  module Topnav = struct
    type t = None | Summary | Log | Files | Refs

    let v ?(active_path = None) repo =
      let open HTML in
      let nav_items =
        [
          (Routes.Repo repo, "Summary", Summary);
          (Routes.Log repo, "Log", Log);
          (Routes.Files repo, "Files", Files);
          (Routes.Refs repo, "Refs", Refs);
        ]
      in
      let li_of_item (route, text, path) =
        let is_active = path = active_path in
        let attrs = if is_active then [ id "active" ] else [] in
        HTML.li attrs [ Routes.link_to route (txt "%s" text) ]
      in
      nav [ id "top" ] [ ul [] @@ List.map li_of_item nav_items ]
  end
end

module Page = struct
  let page_header header1 header2 =
    let header2 =
      if String.starts_with ~prefix:"Unnamed repository" header2 then ""
      else header2
    in
    HTML.(null [ h1 [] [ txt "%s" header1 ]; h2 [] [ txt "%s" header2 ] ])

  let page_footer () =
    let today = Unix.localtime (Unix.time ()) in
    let year = string_of_int (today.Unix.tm_year + 1900) in
    let footer_text = Printf.sprintf "Copyright %s %s" year config.user in
    HTML.footer [] [ txt "%s" footer_text ]

  let render ?(page_title = "Ogit") body_data =
    let open HTML in
    html []
      [
        head []
          [
            title [] "%s" page_title;
            link [ rel "stylesheet"; href "/static/styles.css" ];
            link
              [ rel "icon"; type_ "image/x-icon"; href "/static/git_icon.svg" ];
          ];
        body []
          [
            page_header body_data.title body_data.subtitle;
            body_data.topnav;
            div [ id "main" ] body_data.content;
            page_footer ();
          ];
      ]
end

let root () =
  let all_repositories =
    let repos =
      Sys.readdir config.git_project_root
      |> Array.to_list |> List.sort String.compare
    in
    let li_of_repo repo =
      HTML.li [] [ Routes.link_to (Routes.Repo repo) (txt "%s" repo) ]
    in
    HTML.(div [ id "repositories" ] [ ul [] @@ List.map li_of_repo repos ])
  in
  let body_data =
    {
      title = "Ogit";
      subtitle = "Repositories for " ^ config.user;
      topnav = HTML.null [];
      content = [ all_repositories ];
    }
  in
  respond @@ Page.render body_data

module Repo = struct
  let page_title repo =
    Printf.sprintf "%s — %s" repo (Resolvers.repo_description repo)

  let li_of_author author = HTML.(li [] [ txt "%s" author ])

  let li_of_branch repo (branch : Resolvers.Branch.t) =
    HTML.(li [] [ Routes.link_to (Refs repo) (txt "%s" branch.name) ])

  let li_of_commit repo (commit : Resolvers.Commit.t) =
    let short_hash = Resolvers.short_hash commit.hash in
    let content =
      match commit.message with
      | None -> txt "%s" short_hash
      | Some msg ->
          let route = Routes.Commit (repo, commit.hash) in
          let node =
            HTML.(
              null
                [
                  span [ class_ "commit-hash" ] [ txt "%s" short_hash ];
                  txt " — %s" msg;
                ])
          in
          Routes.link_to route node
    in
    HTML.li [] [ content ]

  let li_of_entry repo (entry : Resolvers.Entry.t) =
    let display_name =
      if entry.perm = 0o040000 then entry.name ^ "/" else entry.name
    in
    let route =
      if entry.perm = 0o040000 then Routes.Files repo
      else Routes.File (repo, entry.hash)
    in
    HTML.(li [] [ Routes.link_to route @@ txt "%s" display_name ])

  let summary repo branches commits authors =
    let content =
      HTML.
        [
          h3 [] [ txt "Branches" ];
          ul [] (List.map (li_of_branch repo) branches);
          h3 [] [ txt "Latest commits" ];
          ul [] (List.map (li_of_commit repo) commits);
          h3 [] [ txt "Authors" ];
          ul [] (List.map li_of_author authors);
        ]
    in
    respond
    @@ Page.render ~page_title:(page_title repo)
         {
           title = repo;
           subtitle = Resolvers.repo_description repo;
           topnav = Components.Topnav.(v ~active_path:Summary repo);
           content;
         }

  let refs repo branches =
    let content =
      HTML.
        [
          h3 [] [ txt "Branches" ];
          ul [] (List.map (li_of_branch repo) branches);
        ]
    in
    respond
    @@ Page.render ~page_title:(page_title repo)
         {
           title = repo;
           subtitle = Resolvers.repo_description repo;
           topnav = Components.Topnav.(v ~active_path:Refs repo);
           content;
         }

  let log repo commits =
    let content =
      HTML.
        [
          h3 [] [ txt "All commits" ];
          ul [] (List.map (li_of_commit repo) commits);
        ]
    in
    respond
    @@ Page.render ~page_title:(page_title repo)
         {
           title = repo;
           subtitle = Resolvers.repo_description repo;
           topnav = Components.Topnav.(v ~active_path:Log repo);
           content;
         }

  let files repo (tree : Resolvers.Tree.t) =
    let content =
      HTML.
        [
          h3 [] [ txt "Files %s" @@ Resolvers.short_hash tree.hash ];
          ul [] (List.map (li_of_entry repo) tree.entries);
        ]
    in
    respond
    @@ Page.render ~page_title:(page_title repo)
         {
           title = Printf.sprintf "%s" repo;
           subtitle = Resolvers.repo_description repo;
           topnav = Components.Topnav.(v ~active_path:Files repo);
           content;
         }

  let file repo (blob : Resolvers.Blob.t) =
    let title = Printf.sprintf "%s" repo in
    let to_numbered_line number line =
      let n = number + 1 in
      HTML.
        [
          a [ id "%d" n; class_ "line-anchor"; href "#%d" n ] [ txt "%d" n ];
          span [ class_ "line" ] [ txt "\t%s\n" line ];
        ]
    in
    let formatted_blob =
      String.split_on_char '\n' blob.content
      |> List.mapi to_numbered_line |> List.flatten
    in
    let content =
      HTML.[ h3 [] [ txt "File" ]; div [ id "blob" ] formatted_blob ]
    in
    respond
    @@ Page.render ~page_title:(page_title repo)
         {
           title;
           subtitle = Resolvers.repo_description repo;
           topnav = Components.Topnav.(v ~active_path:Files repo);
           content;
         }

  let commit repo (commit : Resolvers.Commit.t) =
    let message = match commit.message with Some msg -> msg | None -> "" in
    let title =
      Printf.sprintf "%s : %s" repo @@ Resolvers.short_hash commit.hash
    in
    let content = HTML.[ h3 [] [ txt "%s" message ] ] in
    respond
    @@ Page.render ~page_title:(page_title repo)
         {
           title;
           subtitle = Resolvers.repo_description repo;
           topnav = Components.Topnav.v repo;
           content;
         }
end

let error_page message =
  let open HTML in
  respond
  @@ html []
       [
         head []
           [
             title [] "Fatal error";
             link [ rel "stylesheet"; href "/static/styles.css" ];
             link
               [ rel "icon"; type_ "image/x-icon"; href "/static/git_icon.svg" ];
           ];
         body []
           [
             h1 [] [ txt "Fatal Error" ];
             div
               [ id "main" ]
               [
                 p [] [ b [] [ txt "%s" message ] ];
                 p []
                   [
                     txt
                       "Your best course of action is to press the 'back' \
                        button in your browser.";
                   ];
               ];
           ];
       ]