// SPDX-License-Identifier: MIT
// SPDX-FileCopyrightText: 2026 avtc <tarasenkov@gmail.com>

/** Register the add_to_backlog tool — adds a new feature to the kanban board backlog. */

import { basename } from "node:path";
import { Type } from "@earendil-works/pi-ai";
import type { ExtensionAPI } from "@earendil-works/pi-coding-agent";
import { Text } from "@earendil-works/pi-tui";
import type { KanbanContext } from "../kanban/kanban-context.js";
import { textResult } from "./text-result.js";

/** Register the add_to_backlog tool. */
export function registerAddToBacklogTool(pi: ExtensionAPI, ctx: KanbanContext): void {
  const { getDatabase } = ctx;

  pi.registerTool({
    name: "add_to_backlog",
    label: "Add Feature to Backlog",
    description: [
      "Add a new feature to the kanban board backlog.",
      "Use when decomposing a feature into smaller parts (after user confirmation),",
      "or when the user requests adding a new feature to the board.",
      "Returns the feature ID and slug for reference.",
    ].join(" "),
    parameters: Type.Object({
      slug: Type.String({
        description:
          "Unique slug for the feature (YYYY-MM-DD-<topic> format). Must match the design-doc/plan-doc filename pattern.",
      }),
      title: Type.String({
        maxLength: 200,
        description: "Short, descriptive title for the feature",
      }),
      description: Type.String({
        description: [
          "Detailed feature description with all known context, requirements, and constraints.",
          "Include everything a future agent session would need to start working on this feature",
          "without any prior context — problem statement, proposed approach, key decisions,",
          "relevant code areas, and any user preferences discussed.",
        ].join(" "),
      }),
    }),
    async execute(_toolCallId, params, _signal, _onUpdate, _toolCtx) {
      const database = await getDatabase();

      // Resolve or auto-create project
      const { detectProject } = await import("../kanban/data/kanban-detect-project.js");
      let projectId = await detectProject(database, process.cwd());
      if (!projectId) {
        const cwd = process.cwd();
        // Check if a project with this repo path already exists (e.g. created by a previous call)
        const existingProject = database.findProjectByRepoPath(cwd);
        if (existingProject) {
          projectId = existingProject.id;
        } else {
          projectId = database.createProject({
            name: basename(cwd),
            repoPath: cwd,
          });
        }
      }

      const slug = params.slug;

      // Check for slug collision
      const existingFeature = database.findFeatureBySlug(slug, projectId);
      if (existingFeature) {
        return textResult(
          `A feature with slug "${slug}" already exists (ID: ${existingFeature.id}, lane: ${existingFeature.lane}). Not creating duplicate.`,
        );
      }

      // Prefix description with LLM-generated note
      const prefixedDescription =
        "Important: content generated by LLM, based on user description — " +
        "research and reask user regarding every section and nuances\n\n" +
        params.description;

      // Create feature in backlog
      const featureId = database.createFeature({
        projectId,
        slug,
        title: params.title,
        description: prefixedDescription,
        lane: "backlog",
      });

      return textResult(
        [
          "Feature added to backlog:",
          `- ID: ${featureId}`,
          `- Title: ${params.title}`,
          `- Slug: ${slug}`,
          "- Lane: backlog",
          "",
          "Move it to the design lane to have the auto-designer pick it up, or start a design session manually.",
        ].join("\n"),
      );
    },
    renderCall(args, theme) {
      let text = theme.fg("toolTitle", theme.bold("add_to_backlog "));
      text += theme.fg("accent", `"${args.slug}"`);
      return new Text(text, 0, 0);
    },
    renderResult(result, _options, theme) {
      if (result.content?.[0]?.type === "text") {
        const text = result.content[0].text;
        if (text.includes("already exists")) {
          return new Text(theme.fg("error", text), 0, 0);
        }
        return new Text(theme.fg("success", text), 0, 0);
      }
      return new Text("", 0, 0);
    },
  });
}