open Piaf

type pool = ((module Rapper_helper.CONNECTION), Caqti_error.t) Caqti_eio.Pool.t

(* This is the main handler function for the GET /posts endpoint. *)
(* It takes a database connection pool and a Piaf request as input. *)
let get_posts (db_pool : pool) (_request : Request.t) =
  (* Use a connection from the pool. Caqti_eio.Pool.use handles acquiring and releasing the connection. *)
  Caqti_eio.Pool.use
    (fun conn ->
      (* Call the get_poasts function from the Query module to fetch posts from the database. *)
      let posts_or_error = Query.get_poasts () conn in
      (* Pattern match on the result of the database query. *)
      match posts_or_error with
      (* If the query is successful, the result is a list of posts. *)
      | Ok posts ->
        (* Map the list of post tuples to a Yojson list. *)
        let json =
          `List
            ((* For each post tuple, create a JSON object. *)
             List.map
               (fun (post : Query.post_summary) -> `Assoc [ "title", `String post.title ])
               posts)
        in
        (* Return a 200 OK response with the JSON body. *)
        Ok (Response.of_string ~body:(Yojson.Safe.to_string json) `OK)
      (* If the query fails, log the error and return a 500 Internal Server Error response. *)
      | Error err ->
        Logs.err (fun m -> m "Database error: %a" Caqti_error.pp err);
        Ok (Response.create `Internal_server_error))
    db_pool
;;

(* Handler for GET /posts/:id - gets a single post by ID *)
let get_post post_id (db_pool : pool) (_request : Request.t) =
  Caqti_eio.Pool.use
    (fun conn ->
      let post_or_error = Query.get_poast post_id conn in
      match post_or_error with
      | Ok (Some post) ->
        let json =
          `Assoc
            [ "id", `Int post.id
            ; "title", `String post.title
            ; "content", `String post.content
            ; "date", `String post.date
            ; "tags", `String post.tags
            ; "url", `String post.url
            ]
        in
        Ok (Response.of_string ~body:(Yojson.Safe.to_string json) `OK)
      | Ok None -> Ok (Response.create `Not_found)
      | Error err ->
        Logs.err (fun m -> m "Database error: %a" Caqti_error.pp err);
        Ok (Response.create `Internal_server_error))
    db_pool
;;

(* Handler for GET /comments/:id - gets a single comment by ID *)
let get_comment comment_id (db_pool : pool) (_request : Request.t) =
  Caqti_eio.Pool.use
    (fun conn ->
      let comment_or_error = Query.Query.comment ~id:comment_id conn in
      match comment_or_error with
      | Ok (Some comment) ->
        let json =
          `Assoc
            [ "id", `Int comment.id
            ; "content", `String comment.content
            ; "date", `String comment.date
            ; "tags", `String comment.tags
            ; "url", `String comment.url
            ]
        in
        Ok (Response.of_string ~body:(Yojson.Safe.to_string json) `OK)
      | Ok None -> Ok (Response.create `Not_found)
      | Error err ->
        Logs.err (fun m -> m "Database error: %a" Caqti_error.pp err);
        Ok (Response.create `Internal_server_error))
    db_pool
;;

(* Handler for GET /users/:username/comments - gets comments by a user *)
let get_user_comments username (db_pool : pool) (_request : Request.t) =
  Caqti_eio.Pool.use
    (fun conn ->
      let comments_or_error = Query.Query.user_comments ~username conn in
      match comments_or_error with
      | Ok comments ->
        let json =
          `List
            (List.map
               (fun (comment : Query.comment) ->
                 `Assoc
                   [ "id", `Int comment.id
                   ; "content", `String comment.content
                   ; "date", `String comment.date
                   ; "tags", `String comment.tags
                   ; "url", `String comment.url
                   ])
               comments)
        in
        Ok (Response.of_string ~body:(Yojson.Safe.to_string json) `OK)
      | Error err ->
        Logs.err (fun m -> m "Database error: %a" Caqti_error.pp err);
        Ok (Response.create `Internal_server_error))
    db_pool
;;

(* Handler for GET /posts/:id/comments - gets comments for a post *)
let get_post_comments post_id (db_pool : pool) (_request : Request.t) =
  Caqti_eio.Pool.use
    (fun conn ->
      let comments_or_error = Query.Query.post_comments ~post_id conn in
      match comments_or_error with
      | Ok comments ->
        let json =
          `List
            (List.map
               (fun (comment : Query.comment) ->
                 `Assoc
                   [ "id", `Int comment.id
                   ; "content", `String comment.content
                   ; "date", `String comment.date
                   ; "tags", `String comment.tags
                   ; "url", `String comment.url
                   ])
               comments)
        in
        Ok (Response.of_string ~body:(Yojson.Safe.to_string json) `OK)
      | Error err ->
        Logs.err (fun m -> m "Database error: %a" Caqti_error.pp err);
        Ok (Response.create `Internal_server_error))
    db_pool
;;

(* Handler for GET /comments/:id/children - gets child comments *)
let get_comment_children parent_id (db_pool : pool) (_request : Request.t) =
  Caqti_eio.Pool.use
    (fun conn ->
      let comments_or_error = Query.Query.comment_children ~post_id:parent_id conn in
      match comments_or_error with
      | Ok comments ->
        let json =
          `List
            (List.map
               (fun (comment : Query.comment) ->
                 `Assoc
                   [ "id", `Int comment.id
                   ; "content", `String comment.content
                   ; "date", `String comment.date
                   ; "tags", `String comment.tags
                   ; "url", `String comment.url
                   ])
               comments)
        in
        Ok (Response.of_string ~body:(Yojson.Safe.to_string json) `OK)
      | Error err ->
        Logs.err (fun m -> m "Database error: %a" Caqti_error.pp err);
        Ok (Response.create `Internal_server_error))
    db_pool
;;