/**
 * hive_execute_merge tool — called by the LLM after pre-merge checks.
 * Handles: test merge, execute merge, cleanup worktree + branch.
 */

import type { ExtensionAPI } from "@mariozechner/pi-coding-agent";
import { Type } from "@sinclair/typebox";
import * as fs from "node:fs";
import * as path from "node:path";
import { execFileSync } from "node:child_process";
import {
  testMerge,
  executeMerge,
  removeWorktree,
  deleteBranch,
  getCurrentBranch,
  getDiffStats,
  listWorktrees,
} from "../lib/git-worktree.js";

const MergeParams = Type.Object({
  worktreePath: Type.String({ description: "Absolute path to the worktree directory" }),
  branch: Type.String({ description: "Branch name of the worktree to merge" }),
  featureTitles: Type.Optional(
    Type.Array(Type.String(), { description: "Feature titles that were in this worktree" }),
  ),
});

export function registerWorktreeMergeTool(pi: ExtensionAPI) {
  pi.registerTool({
    name: "hive_execute_merge",
    label: "Hive Merge",
    description:
      "Merge a worktree branch into the main branch. Only call this after verifying the worktree is ready (no uncommitted changes, features complete). Tests for conflicts before merging.",
    parameters: MergeParams,

    async execute(_toolCallId, params, _signal, _onUpdate, ctx) {
      // Find the main project directory (not the worktree)
      const configEntry = getLatestEntry(ctx, "hive-merge-config");
      const projectDir = configEntry?.projectDir ?? ctx.cwd;

      const mainBranch = await getCurrentBranch(projectDir);
      const { worktreePath, branch } = params;
      const featureTitles = params.featureTitles ?? [];

      // ── Step 1: Test merge ─────────────────────────────────────
      const mergeTest = await testMerge(projectDir, branch);

      if (!mergeTest.clean) {
        return {
          content: [{
            type: "text" as const,
            text: `Conflicts detected! Merge aborted.\n\nConflicting files:\n${mergeTest.conflicts.map((f) => `  ${f}`).join("\n")}\n\nHow to resolve:\n  1. cd ${worktreePath}\n  2. git merge ${mainBranch}\n  3. Resolve conflicts manually\n  4. git add . && git commit\n  5. /hive:worktree-merge ${path.basename(worktreePath)}`,
          }],
          details: {},
          isError: true,
        };
      }

      // ── Step 2: Execute merge ──────────────────────────────────
      const featureList = featureTitles.length > 0
        ? featureTitles.join(", ")
        : path.basename(worktreePath);

      const commitMsg = `merge: ${branch} — Features: ${featureList}`;

      try {
        await executeMerge(projectDir, branch, commitMsg);
      } catch (err: any) {
        return {
          content: [{
            type: "text" as const,
            text: `Merge failed: ${err.message}`,
          }],
          details: {},
          isError: true,
        };
      }

      // ── Step 3: Get diff stats ─────────────────────────────────
      const diffStats = await getDiffStats(projectDir, branch);

      // ── Step 3.5: Sandbox cleanup ──────────────────────────────
      try {
        const mapPath = path.join(projectDir, "territory_map.json");
        if (fs.existsSync(mapPath)) {
          const map = JSON.parse(fs.readFileSync(mapPath, "utf-8"));
          const wtEntry = (map.worktrees || []).find((w: any) => w.path === worktreePath || w.branch === branch);
          if (wtEntry?.sandbox?.enabled && wtEntry.sandbox.name) {
            try {
              execFileSync("docker", ["sandbox", "rm", wtEntry.sandbox.name], { stdio: "ignore" });
            } catch { /* already removed or not running */ }
          }
        }
      } catch { /* ignore territory_map read errors */ }

      // ── Step 4: Cleanup ────────────────────────────────────────
      const cleanupErrors: string[] = [];
      try {
        await removeWorktree(projectDir, worktreePath);
      } catch (err: any) {
        cleanupErrors.push(`Worktree removal: ${err.message}`);
      }

      try {
        await deleteBranch(projectDir, branch);
      } catch (err: any) {
        cleanupErrors.push(`Branch deletion: ${err.message}`);
      }

      // ── Step 5: List remaining worktrees ───────────────────────
      const remaining = await listWorktrees(projectDir);
      const otherWorktrees = remaining.filter(
        (wt) => wt.path !== projectDir && !wt.isBare,
      );

      // ── Step 6: Report ─────────────────────────────────────────
      let report = `Merge complete!\n\n`;
      report += `Branch: ${branch} → ${mainBranch}\n`;

      if (featureTitles.length > 0) {
        report += `Features merged:\n${featureTitles.map((t) => `  ${t}`).join("\n")}\n`;
      }

      if (diffStats) {
        report += `\n${diffStats}\n`;
      }

      if (cleanupErrors.length > 0) {
        report += `\nCleanup warnings:\n${cleanupErrors.map((e) => `  ⚠ ${e}`).join("\n")}\n`;
      }

      if (otherWorktrees.length > 0) {
        report += `\nWorktrees remaining:\n`;
        for (const wt of otherWorktrees) {
          report += `  ${path.basename(wt.path)} (branch: ${wt.branch})\n`;
        }
        report += `\nNext: /hive:worktree-merge ${path.basename(otherWorktrees[0].path)}`;
      } else {
        report += `\nAll worktrees merged! 🎉`;
      }

      return {
        content: [{ type: "text" as const, text: report }],
        details: {},
      };
    },
  });
}

function getLatestEntry(ctx: any, customType: string): any {
  const entries = ctx.sessionManager.getEntries();
  for (let i = entries.length - 1; i >= 0; i--) {
    const e = entries[i] as any;
    if (e.type === "custom" && e.customType === customType) {
      return e.data;
    }
  }
  return null;
}