import type { ExtensionCommandContext } from "@earendil-works/pi-coding-agent";
import { matchesKey, Text, truncateToWidth } from "@earendil-works/pi-tui";
import type { LabelProposal } from "./types.ts";

export interface ReviewProposal extends LabelProposal {
  currentLabel?: string;
  replacement: boolean;
  originalIndex: number;
}

export function classifyReviewProposals(
  proposals: LabelProposal[],
  getLabel: (entryId: string) => string | undefined,
): ReviewProposal[] {
  return proposals
    .map((proposal, originalIndex) => {
      const currentLabel = getLabel(proposal.entryId);
      return { ...proposal, currentLabel, replacement: currentLabel !== undefined, originalIndex };
    })
    .sort((a, b) => Number(a.replacement) - Number(b.replacement) || a.originalIndex - b.originalIndex);
}

export async function reviewProposals(
  proposals: LabelProposal[],
  ctx: ExtensionCommandContext,
): Promise<LabelProposal[] | undefined> {
  if (ctx.mode !== "tui") return undefined;
  if (!proposals.length) return [];

  const items = classifyReviewProposals(proposals, (entryId) => ctx.sessionManager.getLabel(entryId));
  const freshCount = items.filter((item) => !item.replacement).length;
  const replacementCount = items.length - freshCount;

  return ctx.ui.custom<LabelProposal[] | undefined>((tui, theme, _kb, done) => {
    let cursor = 0;
    const checked = proposals.map(() => true);
    return {
      invalidate() {},
      render(width: number) {
        const available = Math.max(1, tui.terminal.rows - 7);
        const start = Math.max(0, Math.min(cursor - Math.floor(available / 2), items.length - available));
        const visible = items.slice(start, start + available);
        const lines = [
          theme.fg("accent", theme.bold("Tree label proposals")),
          theme.fg("dim", "↑/↓ move · Space toggle · Enter apply · Esc cancel"),
          theme.fg("muted", `Fresh labels: ${freshCount} · Replacements: ${replacementCount} · uncheck a replacement to keep its current label`),
          "",
        ];
        let previousSection: boolean | undefined;
        visible.forEach((item, visibleIndex) => {
          const index = start + visibleIndex;
          if (item.replacement !== previousSection) {
            lines.push(theme.fg("accent", theme.bold(item.replacement ? "Replacements" : "Fresh labels")));
            previousSection = item.replacement;
          }
          const marker = checked[item.originalIndex] ? "[x]" : "[ ]";
          const pointer = index === cursor ? "›" : " ";
          const change = item.replacement
            ? `${JSON.stringify(item.currentLabel)} → ${JSON.stringify(item.label)}`
            : `new: ${JSON.stringify(item.label)}`;
          const main = truncateToWidth(`${pointer} ${marker} ${item.entryId}  ${change}  (${item.kind})`, Math.max(1, width - 2));
          lines.push(index === cursor ? theme.fg("accent", theme.bold(main)) : main);
          if (index === cursor && item.rationale) lines.push(theme.fg("muted", truncateToWidth(`      ${item.rationale}`, Math.max(1, width - 2))));
        });
        if (items.length > available) lines.push(theme.fg("dim", `  (${cursor + 1}/${items.length})`));
        return new Text(lines.join("\n"), 1, 0).render(width);
      },
      handleInput(data: string) {
        if (matchesKey(data, "up")) cursor = (cursor - 1 + items.length) % items.length;
        else if (matchesKey(data, "down")) cursor = (cursor + 1) % items.length;
        else if (matchesKey(data, "space")) checked[items[cursor].originalIndex] = !checked[items[cursor].originalIndex];
        else if (matchesKey(data, "enter")) done(proposals.filter((_, index) => checked[index]));
        else if (matchesKey(data, "escape") || matchesKey(data, "ctrl+c")) done(undefined);
        tui.requestRender();
      },
    };
  });
}