(*
 * jmap_thread_analyzer.ml - A tool for analyzing email threads using JMAP
 *
 * This binary demonstrates the thread-related capabilities of JMAP,
 * allowing visualization and analysis of conversation threads.
 *)

open Cmdliner
(* Using standard OCaml, no Lwt *)

(* JMAP imports *)
open Jmap
open Jmap.Types
open Jmap.Wire
open Jmap.Methods
open Jmap_email
(* For step 2, we're only testing type checking. No implementations required. *)

(* Dummy Unix module for type checking *)
module Unix = struct
  type tm = {
    tm_sec : int;
    tm_min : int;
    tm_hour : int;
    tm_mday : int;
    tm_mon : int;
    tm_year : int;
    tm_wday : int;
    tm_yday : int;
    tm_isdst : bool
  }
  
  let time () = 0.0
  let gettimeofday () = 0.0
  let mktime tm = (0.0, tm)
  let gmtime _time = {
    tm_sec = 0; tm_min = 0; tm_hour = 0;
    tm_mday = 1; tm_mon = 0; tm_year = 120;
    tm_wday = 0; tm_yday = 0; tm_isdst = false;
  }
  
  (* JMAP connection function - would be in a real implementation *)
  let connect ~host ~username ~password ?auth_method () =
    failwith "Not implemented"
end

(* Dummy ISO8601 module *)
module ISO8601 = struct
  let string_of_datetime _tm = "2023-01-01T00:00:00Z"
end

(** Thread analyzer arguments *)
type thread_analyzer_args = {
  thread_id : string option;
  search : string option;
  limit : int;
  days : int;
  subject : string option;
  participants : string list;
  format : [`Summary | `Detailed | `Timeline | `Graph];
  include_body : bool;
}

(* Email filter helpers - stub implementations for type checking *)
module Email_filter = struct
  let create_fulltext_filter text = Filter.condition (`Assoc [("text", `String text)])
  let subject subj = Filter.condition (`Assoc [("subject", `String subj)])
  let from email = Filter.condition (`Assoc [("from", `String email)])
  let after date = Filter.condition (`Assoc [("receivedAt", `Assoc [("after", `Float date)])])
  let before date = Filter.condition (`Assoc [("receivedAt", `Assoc [("before", `Float date)])])
  let has_attachment () = Filter.condition (`Assoc [("hasAttachment", `Bool true)])
  let unread () = Filter.condition (`Assoc [("isUnread", `Bool true)])
  let in_mailbox id = Filter.condition (`Assoc [("inMailbox", `String id)])
  let to_ email = Filter.condition (`Assoc [("to", `String email)])
end

(* Thread module stub *)
module Thread = struct
  type t = {
    id : string;
    email_ids : string list;
  }
  
  let id thread = thread.id
  let email_ids thread = thread.email_ids
end

(** Command-line arguments **)

let host_arg =
  Arg.(required & opt (some string) None & info ["h"; "host"] 
       ~docv:"HOST" ~doc:"JMAP server hostname")

let user_arg =
  Arg.(required & opt (some string) None & info ["u"; "user"] 
       ~docv:"USERNAME" ~doc:"Username for authentication")

let password_arg =
  Arg.(required & opt (some string) None & info ["p"; "password"] 
       ~docv:"PASSWORD" ~doc:"Password for authentication")

let thread_id_arg =
  Arg.(value & opt (some string) None & info ["t"; "thread"] 
       ~docv:"THREAD_ID" ~doc:"Analyze specific thread by ID")

let search_arg =
  Arg.(value & opt (some string) None & info ["search"] 
       ~docv:"QUERY" ~doc:"Search for threads containing text")

let limit_arg =
  Arg.(value & opt int 10 & info ["limit"] 
       ~docv:"N" ~doc:"Maximum number of threads to display")

let days_arg =
  Arg.(value & opt int 30 & info ["days"] 
       ~docv:"DAYS" ~doc:"Limit to threads from the past N days")

let subject_arg =
  Arg.(value & opt (some string) None & info ["subject"] 
       ~docv:"SUBJECT" ~doc:"Search threads by subject")

let participant_arg =
  Arg.(value & opt_all string [] & info ["participant"] 
       ~docv:"EMAIL" ~doc:"Filter by participant email")

let format_arg =
  Arg.(value & opt (enum [
    "summary", `Summary;
    "detailed", `Detailed;
    "timeline", `Timeline;
    "graph", `Graph;
  ]) `Summary & info ["format"] ~docv:"FORMAT" ~doc:"Output format")

let include_body_arg =
  Arg.(value & flag & info ["include-body"] ~doc:"Include message bodies in output")

(** Thread Analysis Functionality **)

(* Calculate days ago from a date *)
let days_ago date =
  let now = Unix.gettimeofday() in
  int_of_float ((now -. date) /. 86400.0)

(* Parse out email addresses from a participant string - simple version *)
let extract_email participant =
  if String.contains participant '@' then participant
  else participant ^ "@example.com" (* Default domain if none provided *)

(* Create filter for thread queries *)
let create_thread_filter args =
  let open Email_filter in
  let filters = [] in
  
  (* Add search text condition *)
  let filters = match args.search with
    | None -> filters
    | Some text -> create_fulltext_filter text :: filters
  in
  
  (* Add subject condition *)
  let filters = match args.subject with
    | None -> filters
    | Some subj -> Email_filter.subject subj :: filters
  in
  
  (* Add date range based on days *)
  let filters =
    if args.days > 0 then
      let now = Unix.gettimeofday() in
      let past = now -. (float_of_int args.days *. 86400.0) in
      after past :: filters
    else
      filters
  in
  
  (* Add participant filters *)
  let filters =
    List.fold_left (fun acc participant ->
      let email = extract_email participant in
      (* This would need more complex logic to check both from and to fields *)
      from email :: acc
    ) filters args.participants
  in
  
  (* Combine all filters with AND *)
  match filters with
  | [] -> Filter.condition (`Assoc [])  (* Empty filter *)
  | [f] -> f
  | filters -> Filter.and_ filters

(* Display thread in requested format *)
let display_thread thread emails format include_body snippet_map =
  let thread_id = Thread.id thread in
  let email_count = List.length (Thread.email_ids thread) in
  
  (* Sort emails by date for proper display order *)
  let sorted_emails = List.sort (fun e1 e2 ->
    let date1 = Option.value (Types.Email.received_at e1) ~default:0.0 in
    let date2 = Option.value (Types.Email.received_at e2) ~default:0.0 in
    compare date1 date2
  ) emails in
  
  (* Get a snippet for an email if available *)
  let get_snippet email_id =
    match Hashtbl.find_opt snippet_map email_id with
    | Some snippet -> snippet
    | None -> "(No preview available)"
  in
  
  match format with
  | `Summary ->
      Printf.printf "Thread: %s (%d messages)\n\n" thread_id email_count;
      
      (* Print first email subject as thread subject *)
      (match sorted_emails with
      | first :: _ ->
          let subject = Option.value (Types.Email.subject first) ~default:"(No subject)" in
          Printf.printf "Subject: %s\n\n" subject
      | [] -> Printf.printf "No emails available\n\n");
      
      (* List participants *)
      let participants = sorted_emails |> List.fold_left (fun acc email ->
        let from_list = Option.value (Types.Email.from email) ~default:[] in
        from_list |> List.fold_left (fun acc addr ->
          let email = Types.Email_address.email addr in
          if not (List.mem email acc) then email :: acc else acc
        ) acc
      ) [] in
      
      Printf.printf "Participants: %s\n\n" (String.concat ", " participants);
      
      (* Show timespan *)
      (match sorted_emails with
      | first :: _ :: _ :: _ -> (* At least a few messages *)
          let first_date = Option.value (Types.Email.received_at first) ~default:0.0 in
          let last_date = Option.value (Types.Email.received_at (List.hd (List.rev sorted_emails))) ~default:0.0 in
          let datetime_str = ISO8601.string_of_datetime (Unix.gmtime first_date) in
          let first_str = String.sub datetime_str 0 (min 19 (String.length datetime_str)) in
          let datetime_str = ISO8601.string_of_datetime (Unix.gmtime last_date) in
          let last_str = String.sub datetime_str 0 (min 19 (String.length datetime_str)) in
          let duration_days = int_of_float ((last_date -. first_date) /. 86400.0) in
          Printf.printf "Timespan: %s to %s (%d days)\n\n" first_str last_str duration_days
      | _ -> ());
      
      (* Show message count by participant *)
      let message_counts = sorted_emails |> List.fold_left (fun acc email ->
        let from_list = Option.value (Types.Email.from email) ~default:[] in
        match from_list with
        | addr :: _ ->
            let email = Types.Email_address.email addr in
            let count = try Hashtbl.find acc email with Not_found -> 0 in
            Hashtbl.replace acc email (count + 1);
            acc
        | [] -> acc
      ) (Hashtbl.create 10) in
      
      Printf.printf "Messages per participant:\n";
      Hashtbl.iter (fun email count ->
        Printf.printf "  %s: %d messages\n" email count
      ) message_counts;
      Printf.printf "\n"
  
  | `Detailed ->
      Printf.printf "Thread: %s (%d messages)\n\n" thread_id email_count;
      
      (* Print detailed information for each email *)
      sorted_emails |> List.iteri (fun i email ->
        let id = Option.value (Types.Email.id email) ~default:"(unknown)" in
        let subject = Option.value (Types.Email.subject email) ~default:"(No subject)" in
        
        let from_list = Option.value (Types.Email.from email) ~default:[] in
        let from = match from_list with
          | addr :: _ -> Types.Email_address.email addr
          | [] -> "(unknown)"
        in
        
        let date = match Types.Email.received_at email with
          | Some d ->
              let datetime_str = ISO8601.string_of_datetime (Unix.gmtime d) in
              String.sub datetime_str 0 (min 19 (String.length datetime_str))
          | None -> "(unknown)"
        in
        
        let days = match Types.Email.received_at email with
          | Some d -> Printf.sprintf " (%d days ago)" (days_ago d)
          | None -> ""
        in
        
        Printf.printf "Email %d of %d:\n" (i+1) email_count;
        Printf.printf "  ID:      %s\n" id;
        Printf.printf "  Subject: %s\n" subject;
        Printf.printf "  From:    %s\n" from;
        Printf.printf "  Date:    %s%s\n" date days;
        
        let keywords = match Types.Email.keywords email with
          | Some kw -> Types.Keywords.custom_keywords kw |> String.concat ", "
          | None -> "(none)"
        in
        if keywords <> "(none)" then
          Printf.printf "  Flags:   %s\n" keywords;
        
        (* Show preview from snippet if available *)
        Printf.printf "  Snippet: %s\n" (get_snippet id);
        
        (* Show message body if requested *)
        if include_body then
          match Types.Email.text_body email with
          | Some parts when parts <> [] ->
              let first_part = List.hd parts in
              Printf.printf "  Body: %s\n" "(body content would be here in real implementation)";
          | _ -> ();
        
        Printf.printf "\n"
      )
  
  | `Timeline ->
      Printf.printf "Timeline for Thread: %s\n\n" thread_id;
      
      (* Get the first email's subject as thread subject *)
      (match sorted_emails with
      | first :: _ ->
          let subject = Option.value (Types.Email.subject first) ~default:"(No subject)" in
          Printf.printf "Subject: %s\n\n" subject
      | [] -> Printf.printf "No emails available\n\n");
      
      (* Create a timeline visualization *)
      if sorted_emails = [] then
        Printf.printf "No emails to display\n"
      else
        let first_email = List.hd sorted_emails in
        let last_email = List.hd (List.rev sorted_emails) in
        
        let first_date = Option.value (Types.Email.received_at first_email) ~default:0.0 in
        let last_date = Option.value (Types.Email.received_at last_email) ~default:0.0 in
        
        let total_duration = max 1.0 (last_date -. first_date) in
        let timeline_width = 50 in
        
        let datetime_str = ISO8601.string_of_datetime (Unix.gmtime first_date) in
        let start_str = String.sub datetime_str 0 (min 19 (String.length datetime_str)) in
        Printf.printf "Start date: %s\n" start_str;
        
        let datetime_str = ISO8601.string_of_datetime (Unix.gmtime last_date) in
        let end_str = String.sub datetime_str 0 (min 19 (String.length datetime_str)) in
        Printf.printf "End date:   %s\n\n" end_str;
        
        Printf.printf "Timeline: [%s]\n" (String.make timeline_width '-');
        
        sorted_emails |> List.iteri (fun i email ->
          let date = Option.value (Types.Email.received_at email) ~default:0.0 in
          let position = int_of_float (float_of_int timeline_width *. (date -. first_date) /. total_duration) in
          
          let from_list = Option.value (Types.Email.from email) ~default:[] in
          let from = match from_list with
            | addr :: _ -> Types.Email_address.email addr
            | [] -> "(unknown)"
          in
          
          let datetime_str = ISO8601.string_of_datetime (Unix.gmtime date) in
          let date_str = String.sub datetime_str 0 (min 19 (String.length datetime_str)) in
          
          let marker = String.make timeline_width ' ' |> String.mapi (fun j c ->
            if j = position then '*' else if j < position then ' ' else c
          ) in
          
          Printf.printf "%s [%s] %s: %s\n" date_str marker from (get_snippet (Option.value (Types.Email.id email) ~default:""))
        );
        
        Printf.printf "\n"
  
  | `Graph ->
      Printf.printf "Thread Graph for: %s\n\n" thread_id;
      
      (* In a real implementation, this would build a proper thread graph based on
         In-Reply-To and References headers. For this demo, we'll just show a simple tree. *)
      
      (* Get the first email's subject as thread subject *)
      (match sorted_emails with
      | first :: _ ->
          let subject = Option.value (Types.Email.subject first) ~default:"(No subject)" in
          Printf.printf "Subject: %s\n\n" subject
      | [] -> Printf.printf "No emails available\n\n");
      
      (* Create a simple thread tree visualization *)
      if sorted_emails = [] then
        Printf.printf "No emails to display\n"
      else
        let indent level = String.make (level * 2) ' ' in
        
        (* Very simplified threading model - in a real implementation, 
           this would use In-Reply-To and References headers *)
        sorted_emails |> List.iteri (fun i email ->
          let level = min i 4 in  (* Simplified nesting - would be based on real reply chain *)
          
          let id = Option.value (Types.Email.id email) ~default:"(unknown)" in
          
          let from_list = Option.value (Types.Email.from email) ~default:[] in
          let from = match from_list with
            | addr :: _ -> Types.Email_address.email addr
            | [] -> "(unknown)"
          in
          
          let date = match Types.Email.received_at email with
            | Some d -> 
                let datetime_str = ISO8601.string_of_datetime (Unix.gmtime d) in
                String.sub datetime_str 0 (min 19 (String.length datetime_str))
            | None -> "(unknown)"
          in
          
          Printf.printf "%s%s [%s] %s\n" 
            (indent level) 
            (if level = 0 then "+" else if level = 1 then "|-" else "|--")
            date from;
          
          Printf.printf "%s%s\n" (indent (level + 4)) (get_snippet id);
        );
        
        Printf.printf "\n"

(* Command implementation *)
let thread_command host user password thread_id search limit days subject 
                    participant format include_body : int =
  (* Pack arguments into a record for easier passing *)
  let args : thread_analyzer_args = {
    thread_id; search; limit; days; subject; 
    participants = participant; format; include_body
  } in
  
  (* Main workflow would be implemented here using the JMAP library *)
  Printf.printf "JMAP Thread Analyzer\n";
  Printf.printf "Server: %s\n" host;
  Printf.printf "User: %s\n\n" user;
  
  (* This is where the actual JMAP calls would happen, like:
  
  let analyze_threads () =
    let* (ctx, session) = Jmap.Unix.connect 
      ~host ~username:user ~password 
      ~auth_method:(Jmap.Unix.Basic(user, password)) () in
    
    (* Get primary account ID *)
    let account_id = match Jmap.get_primary_account session Jmap_email.capability_mail with
      | Ok id -> id
      | Error _ -> failwith "No mail account found"
    in
    
    match args.thread_id with
    | Some id ->
        (* Analyze a specific thread by ID *)
        let* thread_result = Thread.get ctx
          ~account_id
          ~ids:[id] in
        
        (* Handle thread fetch result *)
        ...
        
    | None ->
        (* Search for threads based on criteria *)
        let filter = create_thread_filter args in
        
        (* Email/query to find emails matching criteria *)
        let* query_result = Email.query ctx
          ~account_id
          ~filter
          ~sort:[Email_sort.received_newest_first ()]
          ~collapse_threads:true
          ~limit:args.limit in
        
        (* Process query results to get thread IDs *)
        ...
  *)
  
  (match thread_id with
  | Some id ->
      Printf.printf "Analyzing thread: %s\n\n" id;
      
      (* Simulate a thread with some emails *)
      let emails = 5 in
      Printf.printf "Thread contains %d emails\n" emails;
      
      (* In a real implementation, we would display the actual thread data here *)
      Printf.printf "Example output format would show thread details here\n"
  
  | None ->
      if search <> None then
        Printf.printf "Searching for threads containing: %s\n" (Option.get search)
      else if subject <> None then
        Printf.printf "Searching for threads with subject: %s\n" (Option.get subject)
      else
        Printf.printf "No specific thread or search criteria provided\n");
      
      if participant <> [] then
        Printf.printf "Filtering to threads involving: %s\n" 
          (String.concat ", " participant);
      
      Printf.printf "Looking at threads from the past %d days\n" days;
      Printf.printf "Showing up to %d threads\n\n" limit;
      
      (* Simulate finding some threads *)
      let thread_count = min limit 3 in
      Printf.printf "Found %d matching threads\n\n" thread_count;
      
      (* In a real implementation, we would display the actual threads here *)
      for i = 1 to thread_count do
        Printf.printf "Thread %d would be displayed here\n\n" i
      done;
  
  (* Since we're only type checking, we'll exit with success *)
  0

(* Command definition *)
let thread_cmd =
  let doc = "analyze email threads using JMAP" in
  let man = [
    `S Manpage.s_description;
    `P "Analyzes email threads with detailed visualization options.";
    `P "Demonstrates how to work with JMAP's thread capabilities.";
    `S Manpage.s_examples;
    `P "  $(mname) -h jmap.example.com -u user@example.com -p secret123 -t thread123";
    `P "  $(mname) -h jmap.example.com -u user@example.com -p secret123 --search \"project update\" --format timeline";
  ] in
  
  let cmd =
    Cmd.v
      (Cmd.info "jmap-thread-analyzer" ~version:"1.0" ~doc ~man)
      Term.(const thread_command $ host_arg $ user_arg $ password_arg $ 
            thread_id_arg $ search_arg $ limit_arg $ days_arg $ 
            subject_arg $ participant_arg $ format_arg $ include_body_arg)
  in
  cmd

(* Main entry point *)
let () = exit (Cmd.eval' thread_cmd)