import { spawnSync } from 'node:child_process';
import path from 'node:path';

export const DEFAULT_ZVEC_QUERY_LIMIT = 8;

function truthy(value, fallback = false) {
  const raw = String(value ?? '').trim().toLowerCase();
  if (!raw) return fallback;
  return ['1', 'true', 'yes', 'on'].includes(raw);
}

export function resolveZvecWorkspaceMode(env = process.env) {
  const raw = String(env.MEMIND_ZVEC_WORKSPACE_MODE ?? 'off').trim().toLowerCase();
  return ['off', 'shadow', 'active'].includes(raw) ? raw : 'off';
}

export function resolveZvecBinary(env = process.env) {
  return String(env.MEMIND_ZVEC_BINARY ?? 'zg').trim() || 'zg';
}

export function resolveZvecWorkspaceRoot(cwd, env = process.env) {
  const explicit = String(env.MEMIND_ZVEC_WORKSPACE_ROOT ?? '').trim();
  if (explicit) return path.resolve(explicit);
  return path.resolve(String(cwd ?? process.cwd()));
}

function parseZvecQueryOutput(stdout) {
  const hits = [];
  const lines = String(stdout ?? '').split('\n');
  for (const line of lines) {
    const match = line.match(/^#(\d+) matchedBy=([^\s]+)\s+(.+?):(\d+)-(\d+)/);
    if (!match) continue;
    hits.push({
      rank: Number(match[1]),
      matchedBy: match[2],
      path: match[3].trim(),
      startLine: Number(match[4]),
      endLine: Number(match[5]),
    });
  }
  return hits;
}

export function searchZvecWorkspace({
  query,
  limit = DEFAULT_ZVEC_QUERY_LIMIT,
  cwd,
  env = process.env,
  spawnImpl = spawnSync,
} = {}) {
  const mode = resolveZvecWorkspaceMode(env);
  const text = String(query ?? '').trim();
  const workspaceRoot = resolveZvecWorkspaceRoot(cwd, env);
  if (mode === 'off' || !text) {
    return {
      mode,
      query: text,
      hits: [],
      applied: false,
      skipped: true,
      reason: mode === 'off' ? 'disabled' : 'empty_query',
    };
  }

  const binary = resolveZvecBinary(env);
  const result = spawnImpl(binary, ['query', text, '--limit', String(limit)], {
    cwd: workspaceRoot,
    env: { ...process.env, ...env },
    encoding: 'utf8',
  });

  if (result.status !== 0) {
    return {
      mode,
      query: text,
      hits: [],
      applied: false,
      skipped: true,
      reason: 'zvec_query_failed',
      stderr: String(result.stderr ?? '').trim().slice(0, 400),
    };
  }

  const hits = parseZvecQueryOutput(result.stdout);
  return {
    mode,
    query: text,
    workspaceRoot,
    hits,
    hitCount: hits.length,
    applied: mode === 'active',
    skipped: false,
    stdoutPreview: String(result.stdout ?? '').trim().slice(0, 1200),
  };
}

export function formatZvecWorkspaceBlock(result) {
  if (!result?.hits?.length) return '';
  const lines = [
    '【Workspace 代码检索】',
    '以下片段来自本工作区索引，仅供开发/排查参考，不是用户生活记忆。',
  ];
  for (const hit of result.hits.slice(0, 8)) {
    lines.push(
      `- ${hit.path}:${hit.startLine}-${hit.endLine} (${hit.matchedBy})`,
    );
  }
  return lines.join('\n').trim();
}

export function isZvecWorkspaceEnabled(env = process.env) {
  return resolveZvecWorkspaceMode(env) !== 'off';
}

export function shouldAttachZvecWorkspaceForTask(taskType, env = process.env) {
  if (!isZvecWorkspaceEnabled(env)) return false;
  const raw = String(env.MEMIND_ZVEC_WORKSPACE_TASK_TYPES ?? 'page_data_dev_complex,repo_refactor,multi_file')
    .split(',')
    .map((item) => item.trim().toLowerCase())
    .filter(Boolean);
  const normalizedTask = String(taskType ?? '').trim().toLowerCase();
  return raw.includes(normalizedTask);
}