import path from 'node:path';
import { initProject, loadConfig } from './config.js';
import { detectQmd, installInstructions, runCommand } from './qmd.js';
import { toPosix } from './fs-utils.js';
import { finishBackgroundJob, startBackgroundJob } from './job-state.js';

const OPERATIONS = new Set(['setup', 'update', 'embed']);

function collectionNameFor(root, options: any = {}) {
  return String(options.name || path.basename(root) || 'project').replace(/[^a-zA-Z0-9_.-]+/g, '-');
}

function firstMask(config) {
  return Array.isArray(config.fileGlobs) && config.fileGlobs.length > 0 ? config.fileGlobs[0] : '**/*.md';
}

function qmdOperationCommand(operation, root, config, options: any = {}) {
  if (operation === 'setup') {
    const targetPath = options.path || '.';
    const command = ['collection', 'add', targetPath, '--name', collectionNameFor(root, options)];
    const mask = options.mask || firstMask(config);
    if (mask) command.push('--mask', mask);
    return command;
  }
  if (operation === 'update') return ['update'];
  if (operation === 'embed') return options.force ? ['embed', '-f'] : ['embed'];
  throw new Error(`Unknown qmd operation: ${operation}`);
}

function qmdOperationPlan(operation, options: any = {}, runtime: any = {}) {
  if (!OPERATIONS.has(operation)) throw new Error(`Unknown qmd operation: ${operation}. Use one of: setup, update, embed`);
  const root = runtime.root || process.cwd();
  initProject(root);
  const config = runtime.config || loadConfig(root);
  const qmd = runtime.qmd || detectQmd(config, root);
  const qmdArgs = qmdOperationCommand(operation, root, config, options);
  const command = qmd.available ? [...qmd.command, ...qmdArgs] : ['qmd', ...qmdArgs];
  const dryRunCommand = `qmd-adaptive-search qmd ${operation} --dry-run`;
  const confirmCommand = `qmd-adaptive-search qmd ${operation} --yes`;

  const details = {
    setup: {
      target: toPosix(path.resolve(root, options.path || '.')),
      sideEffects: [
        'qmd collection config is created or updated for this project path',
        'qmd may scan files matching the configured mask',
        'no embeddings are generated by setup alone'
      ],
      estimatedTime: 'usually seconds to a few minutes, depending on file count'
    },
    update: {
      target: 'all qmd collections unless qmd config narrows the scope',
      sideEffects: [
        'qmd re-indexes changed files',
        'qmd local index metadata may be rewritten',
        'new or changed documents may become pending for embedding'
      ],
      estimatedTime: 'minutes on medium projects; longer on large document sets'
    },
    embed: {
      target: options.force ? 'all qmd chunks (force re-embed)' : 'qmd chunks missing embeddings',
      sideEffects: [
        'qmd downloads or loads embedding model if needed',
        'qmd writes vector embeddings to its local index',
        'CPU/GPU and disk activity can be high during embedding'
      ],
      estimatedTime: 'minutes to much longer, depending on corpus size and model'
    }
  }[operation];

  return {
    operation,
    qmdAvailable: qmd.available,
    qmdCommand: qmd.command,
    command,
    target: details.target,
    sideEffects: details.sideEffects,
    estimatedTime: details.estimatedTime,
    dryRunCommand,
    confirmCommand,
    nextCommandOnFailure: 'qmd-adaptive-search status',
    warnings: qmd.available ? [] : [installInstructions()]
  };
}

function failureHint(operation, errorText) {
  return [
    `qmd ${operation} failed.`,
    errorText ? `Reason: ${errorText}` : 'Reason: qmd exited with a non-zero status.',
    `Next: run \`qmd-adaptive-search qmd ${operation} --dry-run\` to review the plan, then retry with \`--yes\` after fixing qmd output.`,
    'If qmd is missing, run `qmd-adaptive-search install-qmd` first.'
  ].join('\n');
}

function runQmdOperation(operation, options: any = {}, runtime: any = {}) {
  const root = runtime.root || process.cwd();
  const plan = qmdOperationPlan(operation, options, runtime);
  if (options.dryRun || options.planOnly) return { ok: true, dryRun: true, plan };
  if (!options.yes) return { ok: false, confirmationRequired: true, plan, nextCommand: plan.confirmCommand };
  if (!plan.qmdAvailable) return { ok: false, plan, error: 'qmd not found', humanMessage: installInstructions(), nextCommand: 'qmd-adaptive-search install-qmd' };

  const startedJob = startBackgroundJob(root, {
    type: `qmd-${operation}`,
    input: { operation, command: plan.command },
    qmd: { available: plan.qmdAvailable, command: plan.qmdCommand, method: operation }
  });
  const [bin, ...args] = plan.command;
  const result = runCommand([bin], args, { cwd: root, timeoutMs: options.timeoutMs || 30 * 60 * 1000 });
  const finishedAt = new Date().toISOString();
  const errorText = (result.stderr || result.error || '').toString().trim();
  if (result.status !== 0) {
    finishBackgroundJob(root, startedJob, {
      operation,
      status: 'failed',
      finishedAt,
      qmd: { available: plan.qmdAvailable, command: plan.qmdCommand, method: operation },
      result: { ok: false, status: result.status },
      error: errorText || `qmd ${operation} failed`,
      recoveryHint: failureHint(operation, errorText)
    });
    return {
      ok: false,
      plan,
      status: result.status,
      stdout: result.stdout || '',
      stderr: result.stderr || '',
      error: errorText || `qmd ${operation} failed`,
      humanMessage: failureHint(operation, errorText),
      nextCommand: plan.dryRunCommand
    };
  }

  finishBackgroundJob(root, startedJob, {
    operation,
    status: 'completed',
    finishedAt,
    qmd: { available: plan.qmdAvailable, command: plan.qmdCommand, method: operation },
    result: { ok: true, status: result.status }
  });
  return { ok: true, plan, status: result.status, stdout: result.stdout || '', stderr: result.stderr || '' };
}

function nextQmdOperation(root, config, qmd, jobState) {
  if (!qmd.available) return { operation: 'install-qmd', reason: 'qmd is not available', command: 'qmd-adaptive-search install-qmd' };
  if (!jobState.lastSetupJob) return { operation: 'setup', reason: 'no confirmed qmd collection setup has been recorded', command: 'qmd-adaptive-search qmd setup --dry-run' };
  if (!jobState.lastUpdateJob) return { operation: 'update', reason: 'no confirmed qmd index update has been recorded', command: 'qmd-adaptive-search qmd update --dry-run' };
  if (!jobState.lastEmbedJob) return { operation: 'embed', reason: 'no confirmed qmd embedding run has been recorded', command: 'qmd-adaptive-search qmd embed --dry-run' };
  return null;
}

export { qmdOperationPlan, runQmdOperation, nextQmdOperation };