// The Issues view (spec §8).

import * as vscode from "vscode";

import type * as api from "./hubapi";

import { HubAuth } from "./auth";

import { hubUrl } from "./hub";

import type { HubRepo } from "./proposals";

type Node = { kind: "repo"; repo: HubRepo } | { kind: "issue"; repo: HubRepo; i: api.Issue };

export type IssueNode = Extract<Node, { kind: "issue" }>;

export class IssuesProvider implements vscode.TreeDataProvider<Node> {

  private readonly emitter = new vscode.EventEmitter<void>();

  readonly onDidChangeTreeData = this.emitter.event;

  constructor(

    private readonly repos: () => Promise<HubRepo[]>,

    private readonly auth: HubAuth,

  ) {}

  refresh(): void {

    this.emitter.fire();

  }

  getTreeItem(node: Node): vscode.TreeItem {

    if (node.kind === "repo") {

      const item = new vscode.TreeItem(`${node.repo.owner}/${node.repo.name}`, vscode.TreeItemCollapsibleState.Expanded);

      item.iconPath = new vscode.ThemeIcon("repo");

      return item;

    }

    const i = node.i;

    const item = new vscode.TreeItem(`#${i.number} ${i.title}`, vscode.TreeItemCollapsibleState.None);

    item.description = [i.labels.map((l) => l.name).join(", "), i.assignees.length ? "→ " + i.assignees.join(", ") : "", i.milestone ?? ""].filter(Boolean).join(" · ");

    item.iconPath = new vscode.ThemeIcon(i.state === "open" ? "issue-opened" : "issue-closed");

    item.contextValue = "issue";

    item.tooltip = new vscode.MarkdownString(`**${i.title}**\n\nopened by ${i.author} · ${i.comments} comment(s)\n\n${i.body.slice(0, 400)}`);

    item.command = { title: "Open", command: "oxygenhub.openIssue", arguments: [node] };

    return item;

  }

  async getChildren(node?: Node): Promise<Node[]> {

    if (!node) {

      return (await this.repos()).map((repo) => ({ kind: "repo", repo }));

    }

    if (node.kind === "repo") {

      try {

        const me = this.auth.sessionFor(node.repo.base)?.username;

        const list = await this.auth.clientFor(node.repo.base).issues(node.repo.owner, node.repo.name, "open");

        list.sort((a, b) => Number(b.assignees.includes(me ?? "")) - Number(a.assignees.includes(me ?? "")) || b.updated_ms - a.updated_ms);

        return list.map((i) => ({ kind: "issue", repo: node.repo, i }));

      } catch (e) {

        void vscode.window.showWarningMessage(`OxygenHub: ${(e as Error).message}`);

        return [];

      }

    }

    return [];

  }

}

export async function showIssue(auth: HubAuth, repo: HubRepo, i: api.Issue): Promise<void> {

  const comments = await auth.clientFor(repo.base).issueComments(repo.owner, repo.name, i.number);

  const panel = vscode.window.createWebviewPanel("oxygenhub.issue", `#${i.number} ${i.title}`, vscode.ViewColumn.Beside, { enableCommandUris: true });

  const esc = (s: string) => s.replace(/&/g, "&amp;").replace(/</g, "&lt;").replace(/>/g, "&gt;");

  const arg = encodeURIComponent(JSON.stringify([repo.base, repo.owner, repo.name, i.number]));

  const thread = comments.map((c) => `<div class=c><b>${esc(c.author)}</b> <span class=mute>${new Date(c.created_ms).toLocaleString()}</span><pre>${esc(c.body)}</pre></div>`).join("");

  panel.webview.html = `<!doctype html><html><body style="font-family: var(--vscode-font-family); padding: 12px">

  <h2>#${i.number} ${esc(i.title)} <small>${i.state}${i.reason ? ": " + i.reason : ""}</small></h2>

  <p class=mute>opened by ${esc(i.author)} · ${i.labels.map((l) => esc(l.name)).join(", ") || "no labels"} · ${i.assignees.length ? "assigned to " + i.assignees.map(esc).join(", ") : "unassigned"}${i.milestone ? " · " + esc(i.milestone) : ""}</p>

  <p><a href="${hubUrl(repo.base, repo.owner, repo.name, { kind: "issue", number: i.number })}">Open on hub</a> · <a href="command:oxygenhub.commentIssue?${arg}">Comment</a> · <a href="command:oxygenhub.${i.state === "open" ? "closeIssue" : "reopenIssue"}?${arg}">${i.state === "open" ? "Close" : "Reopen"}</a> · <a href="command:oxygenhub.assignMe?${arg}">Assign to me</a></p>

  <pre style="white-space: pre-wrap">${esc(i.body) || "<i>No description.</i>"}</pre>

  ${thread}

  <style>.mute{opacity:.7} .c{border-top:1px solid var(--vscode-widget-border);padding:8px 0} pre{white-space:pre-wrap} small{font-weight:normal;opacity:.7}</style>

  </body></html>`;

}