#!/usr/bin/env bun
/**
 * Generate SKILL.md files from .tmpl templates.
 *
 * Pipeline:
 *   read .tmpl → find {{PLACEHOLDERS}} → resolve from source → format → write .md
 *
 * Supports --dry-run: generate to memory, exit 1 if different from committed file.
 * Used by skill:check and CI freshness checks.
 */

import { COMMAND_DESCRIPTIONS } from '../browse/src/commands';
import { SNAPSHOT_FLAGS } from '../browse/src/snapshot';
import { discoverTemplates } from './discover-skills';
import * as fs from 'fs';
import * as path from 'path';
import type { Host, TemplateContext } from './resolvers/types';
import { HOST_PATHS } from './resolvers/types';
import { RESOLVERS } from './resolvers/index';
import { codexSkillName, transformFrontmatter, extractHookSafetyProse, extractNameAndDescription, condenseOpenAIShortDescription, generateOpenAIYaml } from './resolvers/codex-helpers';
import { generatePlanCompletionAuditShip, generatePlanCompletionAuditReview, generatePlanVerificationExec } from './resolvers/review';

const ROOT = path.resolve(import.meta.dir, '..');
const DRY_RUN = process.argv.includes('--dry-run');

// ─── Host Detection ─────────────────────────────────────────

const HOST_ARG = process.argv.find(a => a.startsWith('--host'));
const HOST: Host = (() => {
  if (!HOST_ARG) return 'claude';
  const val = HOST_ARG.includes('=') ? HOST_ARG.split('=')[1] : process.argv[process.argv.indexOf(HOST_ARG) + 1];
  if (val === 'codex' || val === 'agents') return 'codex';
  if (val === 'claude') return 'claude';
  throw new Error(`Unknown host: ${val}. Use claude, codex, or agents.`);
})();

// HostPaths, HOST_PATHS, and TemplateContext imported from ./resolvers/types (line 7-8)

// ─── Shared Design Constants ────────────────────────────────

/** gstack's 10 AI slop anti-patterns — shared between DESIGN_METHODOLOGY and DESIGN_HARD_RULES */
const AI_SLOP_BLACKLIST = [
  'Purple/violet/indigo gradient backgrounds or blue-to-purple color schemes',
  '**The 3-column feature grid:** icon-in-colored-circle + bold title + 2-line description, repeated 3x symmetrically. THE most recognizable AI layout.',
  'Icons in colored circles as section decoration (SaaS starter template look)',
  'Centered everything (`text-align: center` on all headings, descriptions, cards)',
  'Uniform bubbly border-radius on every element (same large radius on everything)',
  'Decorative blobs, floating circles, wavy SVG dividers (if a section feels empty, it needs better content, not decoration)',
  'Emoji as design elements (rockets in headings, emoji as bullet points)',
  'Colored left-border on cards (`border-left: 3px solid <accent>`)',
  'Generic hero copy ("Welcome to [X]", "Unlock the power of...", "Your all-in-one solution for...")',
  'Cookie-cutter section rhythm (hero → 3 features → testimonials → pricing → CTA, every section same height)',
];

/** OpenAI hard rejection criteria (from "Designing Delightful Frontends with GPT-5.4", Mar 2026) */
const OPENAI_HARD_REJECTIONS = [
  'Generic SaaS card grid as first impression',
  'Beautiful image with weak brand',
  'Strong headline with no clear action',
  'Busy imagery behind text',
  'Sections repeating same mood statement',
  'Carousel with no narrative purpose',
  'App UI made of stacked cards instead of layout',
];

/** OpenAI litmus checks — 7 yes/no tests for cross-model consensus scoring */
const OPENAI_LITMUS_CHECKS = [
  'Brand/product unmistakable in first screen?',
  'One strong visual anchor present?',
  'Page understandable by scanning headlines only?',
  'Each section has one job?',
  'Are cards actually necessary?',
  'Does motion improve hierarchy or atmosphere?',
  'Would design feel premium with all decorative shadows removed?',
];

// ─── Codex Helpers ───────────────────────────────────────────

function codexSkillName(skillDir: string): string {
  if (skillDir === '.' || skillDir === '') return 'gstack';
  // Don't double-prefix: gstack-upgrade → gstack-upgrade (not gstack-gstack-upgrade)
  if (skillDir.startsWith('gstack-')) return skillDir;
  return `gstack-${skillDir}`;
}

function extractNameAndDescription(content: string): { name: string; description: string } {
  const fmStart = content.indexOf('---\n');
  if (fmStart !== 0) return { name: '', description: '' };
  const fmEnd = content.indexOf('\n---', fmStart + 4);
  if (fmEnd === -1) return { name: '', description: '' };

  const frontmatter = content.slice(fmStart + 4, fmEnd);
  const nameMatch = frontmatter.match(/^name:\s*(.+)$/m);
  const name = nameMatch ? nameMatch[1].trim() : '';

  let description = '';
  const lines = frontmatter.split('\n');
  let inDescription = false;
  const descLines: string[] = [];
  for (const line of lines) {
    if (line.match(/^description:\s*\|?\s*$/)) {
      inDescription = true;
      continue;
    }
    if (line.match(/^description:\s*\S/)) {
      description = line.replace(/^description:\s*/, '').trim();
      break;
    }
    if (inDescription) {
      if (line === '' || line.match(/^\s/)) {
        descLines.push(line.replace(/^  /, ''));
      } else {
        break;
      }
    }
  }
  if (descLines.length > 0) {
    description = descLines.join('\n').trim();
  }

  return { name, description };
}

const OPENAI_SHORT_DESCRIPTION_LIMIT = 120;

function condenseOpenAIShortDescription(description: string): string {
  const firstParagraph = description.split(/\n\s*\n/)[0] || description;
  const collapsed = firstParagraph.replace(/\s+/g, ' ').trim();
  if (collapsed.length <= OPENAI_SHORT_DESCRIPTION_LIMIT) return collapsed;

  const truncated = collapsed.slice(0, OPENAI_SHORT_DESCRIPTION_LIMIT - 3);
  const lastSpace = truncated.lastIndexOf(' ');
  const safe = lastSpace > 40 ? truncated.slice(0, lastSpace) : truncated;
  return `${safe}...`;
}

function generateOpenAIYaml(displayName: string, shortDescription: string): string {
  return `interface:
  display_name: ${JSON.stringify(displayName)}
  short_description: ${JSON.stringify(shortDescription)}
  default_prompt: ${JSON.stringify(`Use ${displayName} for this task.`)}
policy:
  allow_implicit_invocation: true
`;
}

/**
 * Transform frontmatter for Codex: keep only name + description.
 * Strips allowed-tools, hooks, version, and all other fields.
 * Handles multiline block scalar descriptions (YAML | syntax).
 */
function transformFrontmatter(content: string, host: Host): string {
  if (host === 'claude') return content;

  const fmStart = content.indexOf('---\n');
  if (fmStart !== 0) return content;
  const fmEnd = content.indexOf('\n---', fmStart + 4);
  if (fmEnd === -1) return content;
  const body = content.slice(fmEnd + 4); // includes the leading \n after ---
  const { name, description } = extractNameAndDescription(content);

  // Codex 1024-char description limit — fail build, don't ship broken skills
  const MAX_DESC = 1024;
  if (description.length > MAX_DESC) {
    throw new Error(
      `Codex description for "${name}" is ${description.length} chars (max ${MAX_DESC}). ` +
      `Compress the description in the .tmpl file.`
    );
  }

  // Re-emit Codex frontmatter (name + description only)
  const indentedDesc = description.split('\n').map(l => `  ${l}`).join('\n');
  const codexFm = `---\nname: ${name}\ndescription: |\n${indentedDesc}\n---`;
  return codexFm + body;
}

/**
 * Extract hook descriptions from frontmatter for inline safety prose.
 * Returns a description of what the hooks do, or null if no hooks.
 */
function extractHookSafetyProse(tmplContent: string): string | null {
  if (!tmplContent.match(/^hooks:/m)) return null;

  // Parse the hook matchers to build a human-readable safety description
  const matchers: string[] = [];
  const matcherRegex = /matcher:\s*"(\w+)"/g;
  let m;
  while ((m = matcherRegex.exec(tmplContent)) !== null) {
    if (!matchers.includes(m[1])) matchers.push(m[1]);
  }

  if (matchers.length === 0) return null;

  // Build safety prose based on what tools are hooked
  const toolDescriptions: Record<string, string> = {
    Bash: 'check bash commands for destructive operations (rm -rf, DROP TABLE, force-push, git reset --hard, etc.) before execution',
    Edit: 'verify file edits are within the allowed scope boundary before applying',
    Write: 'verify file writes are within the allowed scope boundary before applying',
  };

  const safetyChecks = matchers
    .map(t => toolDescriptions[t] || `check ${t} operations for safety`)
    .join(', and ');

  return `> **Safety Advisory:** This skill includes safety checks that ${safetyChecks}. When using this skill, always pause and verify before executing potentially destructive operations. If uncertain about a command's safety, ask the user for confirmation before proceeding.`;
}

// ─── Template Processing ────────────────────────────────────

const GENERATED_HEADER = `<!-- AUTO-GENERATED from {{SOURCE}} — do not edit directly -->\n<!-- Regenerate: bun run gen:skill-docs -->\n`;

function processTemplate(tmplPath: string, host: Host = 'claude'): { outputPath: string; content: string; symlinkLoop?: boolean } {
  const tmplContent = fs.readFileSync(tmplPath, 'utf-8');
  const relTmplPath = path.relative(ROOT, tmplPath);
  let outputPath = tmplPath.replace(/\.tmpl$/, '');

  // Determine skill directory relative to ROOT
  const skillDir = path.relative(ROOT, path.dirname(tmplPath));

  let outputDir: string | null = null;

  // For codex host, route output to .agents/skills/{codexSkillName}/SKILL.md
  let symlinkLoop = false;
  if (host === 'codex') {
    const codexName = codexSkillName(skillDir === '.' ? '' : skillDir);
    outputDir = path.join(ROOT, '.agents', 'skills', codexName);
    fs.mkdirSync(outputDir, { recursive: true });
    outputPath = path.join(outputDir, 'SKILL.md');

    // Guard against symlink loops: if .agents/skills/gstack → repo root,
    // writing to .agents/skills/gstack/SKILL.md would overwrite the Claude version.
    // Skip the write entirely for this skill — the codex content is still generated
    // for token budget tracking.
    const claudePath = tmplPath.replace(/\.tmpl$/, '');
    try {
      const resolvedClaude = fs.realpathSync(claudePath);
      const resolvedCodex = fs.realpathSync(path.dirname(outputPath)) + '/' + path.basename(outputPath);
      if (resolvedClaude === resolvedCodex) {
        symlinkLoop = true;
      }
    } catch {
      // realpathSync fails if file doesn't exist yet — that's fine, no symlink loop
    }
  }

  // Extract skill name from frontmatter for TemplateContext
  const { name: extractedName, description: extractedDescription } = extractNameAndDescription(tmplContent);
  const skillName = extractedName || path.basename(path.dirname(tmplPath));

  // Extract benefits-from list from frontmatter (inline YAML: benefits-from: [a, b])
  const benefitsMatch = tmplContent.match(/^benefits-from:\s*\[([^\]]*)\]/m);
  const benefitsFrom = benefitsMatch
    ? benefitsMatch[1].split(',').map(s => s.trim()).filter(Boolean)
    : undefined;

  // Extract preamble-tier from frontmatter (1-4, controls which preamble sections are included)
  const tierMatch = tmplContent.match(/^preamble-tier:\s*(\d+)$/m);
  const preambleTier = tierMatch ? parseInt(tierMatch[1], 10) : undefined;

  const ctx: TemplateContext = { skillName, tmplPath, benefitsFrom, host, paths: HOST_PATHS[host], preambleTier };

  // Replace placeholders
  let content = tmplContent.replace(/\{\{(\w+)\}\}/g, (match, name) => {
    const resolver = RESOLVERS[name];
    if (!resolver) throw new Error(`Unknown placeholder {{${name}}} in ${relTmplPath}`);
    return resolver(ctx);
  });

  // Check for any remaining unresolved placeholders
  const remaining = content.match(/\{\{(\w+)\}\}/g);
  if (remaining) {
    throw new Error(`Unresolved placeholders in ${relTmplPath}: ${remaining.join(', ')}`);
  }

  // For codex host: transform frontmatter and replace Claude-specific paths
  if (host === 'codex') {
    // Extract hook safety prose BEFORE transforming frontmatter (which strips hooks)
    const safetyProse = extractHookSafetyProse(tmplContent);

    // Transform frontmatter: keep only name + description
    content = transformFrontmatter(content, host);

    // Insert safety advisory at the top of the body (after frontmatter)
    if (safetyProse) {
      const bodyStart = content.indexOf('\n---') + 4;
      content = content.slice(0, bodyStart) + '\n' + safetyProse + '\n' + content.slice(bodyStart);
    }

    // Replace remaining hardcoded Claude paths with host-appropriate paths
    content = content.replace(/~\/\.claude\/skills\/gstack/g, ctx.paths.skillRoot);
    content = content.replace(/\.claude\/skills\/gstack/g, ctx.paths.localSkillRoot);
    content = content.replace(/\.claude\/skills\/review/g, '.agents/skills/gstack/review');
    content = content.replace(/\.claude\/skills/g, '.agents/skills');

    if (outputDir && !symlinkLoop) {
      const codexName = codexSkillName(skillDir === '.' ? '' : skillDir);
      const agentsDir = path.join(outputDir, 'agents');
      fs.mkdirSync(agentsDir, { recursive: true });
      const displayName = codexName;
      const shortDescription = condenseOpenAIShortDescription(extractedDescription);
      fs.writeFileSync(path.join(agentsDir, 'openai.yaml'), generateOpenAIYaml(displayName, shortDescription));
    }
  }

  // Prepend generated header (after frontmatter)
  const header = GENERATED_HEADER.replace('{{SOURCE}}', path.basename(tmplPath));
  const fmEnd = content.indexOf('---', content.indexOf('---') + 3);
  if (fmEnd !== -1) {
    const insertAt = content.indexOf('\n', fmEnd) + 1;
    content = content.slice(0, insertAt) + header + content.slice(insertAt);
  } else {
    content = header + content;
  }

  return { outputPath, content, symlinkLoop };
}

// ─── Main ───────────────────────────────────────────────────

function findTemplates(): string[] {
  return discoverTemplates(ROOT).map(t => path.join(ROOT, t.tmpl));
}

let hasChanges = false;
const tokenBudget: Array<{ skill: string; lines: number; tokens: number }> = [];

for (const tmplPath of findTemplates()) {
  // Skip /codex skill for codex host (self-referential — it's a Claude wrapper around codex exec)
  if (HOST === 'codex') {
    const dir = path.basename(path.dirname(tmplPath));
    if (dir === 'codex') continue;
  }

  const { outputPath, content, symlinkLoop } = processTemplate(tmplPath, HOST);
  const relOutput = path.relative(ROOT, outputPath);

  if (symlinkLoop) {
    console.log(`SKIPPED (symlink loop): ${relOutput}`);
  } else if (DRY_RUN) {
    const existing = fs.existsSync(outputPath) ? fs.readFileSync(outputPath, 'utf-8') : '';
    if (existing !== content) {
      console.log(`STALE: ${relOutput}`);
      hasChanges = true;
    } else {
      console.log(`FRESH: ${relOutput}`);
    }
  } else {
    fs.writeFileSync(outputPath, content);
    console.log(`GENERATED: ${relOutput}`);
  }

  // Track token budget
  const lines = content.split('\n').length;
  const tokens = Math.round(content.length / 4); // ~4 chars per token
  tokenBudget.push({ skill: relOutput, lines, tokens });
}

if (DRY_RUN && hasChanges) {
  console.error('\nGenerated SKILL.md files are stale. Run: bun run gen:skill-docs');
  process.exit(1);
}

// Print token budget summary
if (!DRY_RUN && tokenBudget.length > 0) {
  tokenBudget.sort((a, b) => b.lines - a.lines);
  const totalLines = tokenBudget.reduce((s, t) => s + t.lines, 0);
  const totalTokens = tokenBudget.reduce((s, t) => s + t.tokens, 0);

  console.log('');
  console.log(`Token Budget (${HOST} host)`);
  console.log('═'.repeat(60));
  for (const t of tokenBudget) {
    const name = t.skill.replace(/\/SKILL\.md$/, '').replace(/^\.agents\/skills\//, '');
    console.log(`  ${name.padEnd(30)} ${String(t.lines).padStart(5)} lines  ~${String(t.tokens).padStart(6)} tokens`);
  }
  console.log('─'.repeat(60));
  console.log(`  ${'TOTAL'.padEnd(30)} ${String(totalLines).padStart(5)} lines  ~${String(totalTokens).padStart(6)} tokens`);
  console.log('');
}