// The Proposals view (spec §5): per repository with a hub remote, three

// buckets, a detail webview, and the actions.

import * as vscode from "vscode";

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

import { HubAuth } from "./auth";

import { hubUrl, needsMe, parseRepoUrl } from "./hub";

import type { OxygenAPI, RepositoryHandle } from "./oxygenapi";

/** A repository in the workspace with a hub remote. */

export interface HubRepo {

  handle: RepositoryHandle;

  base: string;

  owner: string;

  name: string;

  remote: string;

}

/** Just enough to name a repository on a hub. */

export type RepoRef = Pick<HubRepo, "base" | "owner" | "name">;

/** Find the hub remotes of every repository the Oxygen extension knows. */

export async function hubRepos(oxygen: OxygenAPI, auth: HubAuth): Promise<HubRepo[]> {

  const out: HubRepo[] = [];

  const bases = auth.bases();

  for (const handle of oxygen.repositories) {

    let remotes: { name: string; url: string }[] = [];

    try {

      remotes = await handle.remotes();

    } catch {

      continue;

    }

    for (const r of remotes) {

      const p = parseRepoUrl(r.url);

      if (p && bases.includes(p.base)) {

        out.push({ handle, base: p.base, owner: p.owner, name: p.name, remote: r.name });

        break;

      }

    }

  }

  return out;

}

type Node =

  | { kind: "repo"; repo: HubRepo }

  | { kind: "bucket"; repo: HubRepo; label: string; items: api.Proposal[] }

  | { kind: "proposal"; repo: HubRepo; p: api.Proposal }

  | { kind: "file"; repo: HubRepo; p: api.Proposal; f: api.ProposalFile };

const FILE_ICONS: Record<string, string> = { added: "diff-added", removed: "diff-removed", renamed: "diff-renamed", modified: "diff-modified" };

export class ProposalsProvider implements vscode.TreeDataProvider<Node> {

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

  readonly onDidChangeTreeData = this.emitter.event;

  private cache = new Map<string, api.Proposal[]>();

  private files = new Map<string, api.ProposalFile[]>();

  constructor(

    private readonly oxygen: () => OxygenAPI | undefined,

    private readonly auth: HubAuth,

  ) {}

  refresh(): void {

    this.cache.clear();

    this.files.clear();

    this.emitter.fire();

  }

  async repos(): Promise<HubRepo[]> {

    const o = this.oxygen();

    return o ? hubRepos(o, this.auth) : [];

  }

  async proposalsOf(repo: HubRepo): Promise<api.Proposal[]> {

    const key = `${repo.base}/${repo.owner}/${repo.name}`;

    const hit = this.cache.get(key);

    if (hit) {

      return hit;

    }

    const list = await this.auth.clientFor(repo.base).proposals(repo.owner, repo.name);

    this.cache.set(key, list);

    return list;

  }

  /** The files a proposal changes, cached until the next refresh. */

  async filesOf(repo: HubRepo, p: api.Proposal): Promise<api.ProposalFile[]> {

    const key = `${repo.base}/${repo.owner}/${repo.name}#${p.number}`;

    const hit = this.files.get(key);

    if (hit) {

      return hit;

    }

    const list = await this.auth.clientFor(repo.base).proposalFiles(repo.owner, repo.name, p.number);

    this.files.set(key, list);

    return list;

  }

  getTreeItem(node: Node): vscode.TreeItem {

    switch (node.kind) {

      case "repo": {

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

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

        item.contextValue = "repo";

        return item;

      }

      case "bucket": {

        const item = new vscode.TreeItem(`${node.label} (${node.items.length})`, node.items.length ? vscode.TreeItemCollapsibleState.Expanded : vscode.TreeItemCollapsibleState.Collapsed);

        item.contextValue = "bucket";

        return item;

      }

      case "proposal": {

        const p = node.p;

        const item = new vscode.TreeItem(`#${p.number} ${p.title}`, vscode.TreeItemCollapsibleState.Collapsed);

        const sealed = p.approvals.filter((a) => a.sealed).length;

        const chips = [p.state === "draft" ? "draft" : "", p.conflicted ? "conflicts" : "", p.landable ? "landable" : "", sealed ? `${sealed} sealed` : ""].filter(Boolean).join(" · ");

        item.description = `${p.author} → ${p.target}${chips ? " · " + chips : ""}`;

        item.tooltip = new vscode.MarkdownString(`**${p.title}** by ${p.author}\n\n${p.changes.length} change(s) into ${p.target}\n\n${p.blockers.length ? "Blocked: " + p.blockers.join("; ") : "Ready to land"}`);

        item.iconPath = new vscode.ThemeIcon(p.conflicted ? "warning" : p.landable ? "pass" : p.state === "draft" ? "circle-outline" : "git-pull-request");

        item.contextValue = "proposal";

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

        return item;

      }

      case "file": {

        const f = node.f;

        const slash = f.path.lastIndexOf("/");

        const item = new vscode.TreeItem(f.path.slice(slash + 1), vscode.TreeItemCollapsibleState.None);

        const dir = slash > 0 ? f.path.slice(0, slash) : "";

        item.description = [dir, f.from ? `from ${f.from}` : "", f.added || f.removed ? `+${f.added} −${f.removed}` : f.kind].filter(Boolean).join(" · ");

        item.tooltip = `${f.path} (${f.kind})`;

        item.iconPath = new vscode.ThemeIcon(FILE_ICONS[f.kind] ?? "diff");

        item.contextValue = "proposalFile";

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

        return item;

      }

    }

  }

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

    if (!node) {

      const repos = await this.repos();

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

    }

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

      let list: api.Proposal[] = [];

      try {

        list = await this.proposalsOf(node.repo);

      } catch (e) {

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

        return [];

      }

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

      const mine = list.filter((p) => p.author === me);

      const needing = list.filter((p) => needsMe(p, me));

      const rest = list.filter((p) => !mine.includes(p) && !needing.includes(p));

      return [

        { kind: "bucket", repo: node.repo, label: "Needing me", items: needing },

        { kind: "bucket", repo: node.repo, label: "Mine", items: mine },

        { kind: "bucket", repo: node.repo, label: "Open", items: rest },

      ];

    }

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

      return node.items.map((p) => ({ kind: "proposal", repo: node.repo, p }));

    }

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

      try {

        const files = await this.filesOf(node.repo, node.p);

        return files.map((f) => ({ kind: "file", repo: node.repo, p: node.p, f }));

      } catch (e) {

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

      }

    }

    return [];

  }

}

export type ProposalNode = Extract<Node, { kind: "proposal" }>;

export type ProposalFileNode = Extract<Node, { kind: "file" }>;

/** The detail webview. */

export function showDetail(repo: HubRepo, p: api.Proposal, checks: api.Check[]): void {

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

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

  const changes = p.changes.map((c) => `<li><code>${c.hash.slice(0, 12)}</code> ${esc(c.message.split("\n")[0])} <span class="mute">${esc(c.author.name)} · ${c.signature.status}</span></li>`).join("");

  const approvals = p.approvals.map((a) => `<li>${a.sealed ? "◈" : "○"} ${esc(a.account)}${a.sealed ? "" : " (seal pending)"}</li>`).join("") || "<li class=mute>none</li>";

  const blockers = p.blockers.map((b) => `<li>✘ ${esc(b)}</li>`).join("") || "<li>✔ ready to land</li>";

  const checkRows = checks.map((c) => `<li>${c.status === "passed" ? "✔" : c.status === "failed" ? "✘" : "…"} ${esc(c.name)} <span class=mute>${c.status}${c.summary ? " · " + esc(c.summary) : ""}</span></li>`).join("") || "<li class=mute>none</li>";

  const url = hubUrl(repo.base, repo.owner, repo.name, { kind: "proposal", number: p.number });

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

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

  <h2>#${p.number} ${esc(p.title)} <small>${p.state}</small></h2>

  <p>${esc(p.author)} wants <b>${esc(JSON.stringify(p.source))}</b> into <b>${esc(p.target)}</b> · ${p.changes.length} change(s)${p.conflicted ? " · <b>conflicts</b>" : ""}</p>

  <p><a href="${url}">Open on hub</a> · <a href="command:oxygenhub.openProposalChanges?${arg}">View changes</a> · <a href="command:oxygenhub.checkoutProposal?${arg}">Check out</a> · <a href="command:oxygenhub.review?${arg}">Review</a> · <a href="command:oxygenhub.sealApproval?${arg}">Seal approval</a> · <a href="command:oxygenhub.land?${arg}">Land</a></p>

  <div>${p.body ? `<pre style="white-space: pre-wrap">${esc(p.body)}</pre>` : ""}</div>

  <h3>Landing</h3><ul>${blockers}</ul>

  <h3>Approvals</h3><ul>${approvals}</ul>

  <h3>Checks</h3><ul>${checkRows}</ul>

  <h3>Changes</h3><ul>${changes}</ul>

  <style>.mute{opacity:.7} small{font-weight:normal;opacity:.7}</style>

  </body></html>`;

}