import { useMemo } from "react";
import { useFetch } from "../hooks";
import { fmtCost, fmtDate, fmtRelative, useT, type Key } from "../i18n";
import { navigate } from "../router";
import { useStore } from "../store";
import type { Session } from "../types";
import { Icon } from "./Icon";
import { basename } from "./FileFigure";

interface Overview {
  sessions: Record<string, { files: number; check: string | null; checks_failed: number; cost: number }>;
  check: { command: string; enabled: boolean } | null;
  defaults: { model?: string; agent?: string; permission_mode?: string; color?: string; instructions?: string; folder?: string } | null;
  currency: string;
}

const day = (ms: number) => new Date(ms).toDateString();

/** One project folder: its chats as a timeline (newest first) with what each one did. */
export function ProjectPage({ cwd, onMenu }: { cwd: string; onMenu: () => void }) {
  const t = useT();
  const all = useStore((s) => s.sessions);
  const { data } = useFetch<Overview>(`/projects/overview?cwd=${encodeURIComponent(cwd)}`);
  const sessions = useMemo(() => all.filter((s) => s.cwd === cwd && !s.archived).sort((a, b) => b.updated_at - a.updated_at), [all, cwd]);
  const archived = all.filter((s) => s.cwd === cwd && s.archived).length;

  // Day groups: "Today", "Yesterday", date.
  const groups = useMemo(() => {
    const out: { label: string; items: Session[] }[] = [];
    const today = day(Date.now());
    const yesterday = day(Date.now() - 86_400_000);
    for (const s of sessions) {
      const d = day(s.updated_at);
      const label = d === today ? t("project.today") : d === yesterday ? t("project.yesterday") : fmtDate(s.updated_at, false);
      const last = out[out.length - 1];
      if (last?.label === label) last.items.push(s);
      else out.push({ label, items: [s] });
    }
    return out;
  }, [sessions, t]);

  const totalCost = sessions.reduce((n, s) => n + (data?.sessions[s.id]?.cost ?? 0), 0);
  const totalFiles = sessions.reduce((n, s) => n + (data?.sessions[s.id]?.files ?? 0), 0);

  const newChat = () => {
    try {
      localStorage.setItem("codecraft.lastDir", cwd);
    } catch {
      // Without storage the wizard starts at its usual folder.
    }
    navigate("/new");
  };

  return (
    <>
      <div className="topbar">
        <button className="ghost menu-btn" onClick={onMenu} aria-label={t("nav.menu")}>
          <Icon name="menu" />
        </button>
        <div className="grow">
          <h1>
            <Icon name="folder" /> {basename(cwd) || "/"}
          </h1>
          <div className="path mono">{cwd}</div>
        </div>
        <button className="small primary" onClick={newChat}>
          <Icon name="plus" /> {t("project.newChat")}
        </button>
      </div>
      <div className="chat-scroll">
        <div className="chat project-page">
          <div className="project-summary">
            <span className="chip">{t("project.chats", { n: sessions.length })}</span>
            {totalFiles > 0 && <span className="chip">{t("project.files", { n: totalFiles })}</span>}
            {data && totalCost > 0 && <span className="chip">{fmtCost(totalCost, data.currency)}</span>}
            {data?.check?.enabled && (
              <span className="chip mono" title={t("check.title")}>
                <Icon name="check" className="tiny" /> {data.check.command}
              </span>
            )}
            {data?.defaults?.model && (
              <span className="chip" title={t("projectDefaults.hint")}>
                <Icon name="template" className="tiny" /> {data.defaults.model.split("/").pop()}
              </span>
            )}
            {archived > 0 && <span className="hint">{t("project.archived", { n: archived })}</span>}
          </div>
          {sessions.length === 0 && <div className="empty">{t("project.empty")}</div>}
          {groups.map((g) => (
            <section key={g.label} className="timeline-day">
              <h3>{g.label}</h3>
              <ol className="timeline">
                {g.items.map((s) => {
                  const info = data?.sessions[s.id];
                  return (
                    <li key={s.id} data-color={s.color} className={s.color ? "tagged" : ""}>
                      <a href={`#/s/${s.id}`} onClick={(e) => (e.preventDefault(), navigate(`/s/${s.id}`))}>
                        <div className="tl-title">
                          <span className={s.color ? "color-badge" : undefined}>
                            {s.icon && <Icon name={s.icon} className="tiny chat-icon" />}
                            {s.title || t("session.untitled")}
                          </span>
                          <span className="tl-when" title={fmtDate(s.updated_at)}>
                            {fmtRelative(s.updated_at)}
                          </span>
                        </div>
                        {s.summary && <div className="tl-summary">{s.summary}</div>}
                        <div className="tl-meta">
                          <span>{s.agent}</span>
                          <span>{s.model.split("/").pop()}</span>
                          {!!info?.files && <span>{t("project.files", { n: info.files })}</span>}
                          {info?.check && (
                            <span className={`check-${info.check}`}>
                              <Icon name={info.check === "passed" ? "check" : info.check === "running" ? "clock" : "x-mark"} className="tiny" /> {t(`check.${info.check}` as Key)}
                            </span>
                          )}
                          {!!info?.checks_failed && <span className="check-failed">{t("project.checksFailed", { n: info.checks_failed })}</span>}
                          {!!info?.cost && data && <span>{fmtCost(info.cost, data.currency)}</span>}
                        </div>
                      </a>
                    </li>
                  );
                })}
              </ol>
            </section>
          ))}
        </div>
      </div>
    </>
  );
}