import type { SkillConfigRecord } from '@electron/utils/skill-config';
import type { ToolRenderHints } from '@runtime/shared/chat-model';

const FRONTMATTER_PATTERN = /^---\s*\r?\n([\s\S]*?)\r?\n---/;
const FILE_EXTENSION_PATTERN = /\.[a-z0-9]{2,8}\b/gi;
const ENV_VAR_PATTERN = /\$\{([A-Z][A-Z0-9_]+)\}/g;
const QUOTED_TEXT_PATTERN = /"([^"\n]{2,80})"|'([^'\n]{2,80})'/g;
const CODE_FENCE_PATTERN = /```([^\n`]*)\r?\n([\s\S]*?)```/g;
const SPREADSHEET_EXTENSIONS = ['.xlsx', '.xls', '.xlsm', '.csv', '.tsv', '.ods'];
const DOCUMENT_EXTENSIONS = ['.pdf', '.docx', '.doc', '.pptx', '.ppt', '.odt', '.odp', '.rtf'];
const COMMON_FILE_EXTENSIONS = [
  ...SPREADSHEET_EXTENSIONS,
  ...DOCUMENT_EXTENSIONS,
  '.txt',
  '.md',
  '.json',
  '.xml',
  '.html',
  '.htm',
  '.png',
  '.jpg',
  '.jpeg',
  '.gif',
  '.bmp',
  '.webp',
  '.svg',
];

const OPERATION_KEYWORDS: Array<[string, string[]]> = [
  ['search', ['search', 'look up', 'lookup', 'find', 'discover']],
  ['research', ['research', 'investigate']],
  ['extract', ['extract', 'scrape']],
  ['crawl', ['crawl', 'map']],
  ['read', ['read', 'open', 'inspect', 'review']],
  ['analyze', ['analyze', 'analysis', 'summarize', 'statistics']],
  ['create', ['create', 'build', 'generate', 'produce']],
  ['edit', ['edit', 'modify', 'update', 'fill cells', 'add formulas']],
  ['convert', ['convert', 'transform', 'export']],
  ['validate', ['validate', 'check formulas', 'verify']],
  ['repair', ['repair', 'fix', 'recover']],
  ['format', ['format', 'styling', 'style']],
];

export interface SkillCapability {
  skillKey: string;
  slug: string;
  name: string;
  description: string;
  enabled: boolean;
  category: string;
  version?: string;
  source?: string;
  baseDir?: string;
  manifestPath?: string;
  allowedTools: string[];
  operationHints: string[];
  triggerHints: string[];
  inputExtensions: string[];
  requiredEnvVars: string[];
  requiresAuth: boolean;
  plannerSummary: string;
  commandExamples?: string[];
  renderHints?: ToolRenderHints;
}

export interface SkillCapabilityParserInput {
  skillKey: string;
  config?: Partial<SkillConfigRecord> & {
    enabled?: boolean;
    apiKey?: string;
    env?: Record<string, string>;
  };
  manifestContent?: string | null;
}

type ParsedFrontmatter = {
  name?: string;
  description?: string;
  version?: string;
  category?: string;
  allowedTools: string[];
};

function uniq(values: Array<string | undefined | null>): string[] {
  return Array.from(new Set(values.map((value) => value?.trim()).filter(Boolean) as string[]));
}

function extractFrontmatter(markdown?: string | null): { frontmatter: string; body: string } {
  if (!markdown) {
    return { frontmatter: '', body: '' };
  }

  const match = markdown.match(FRONTMATTER_PATTERN);
  if (!match) {
    return { frontmatter: '', body: markdown };
  }

  return {
    frontmatter: match[1] || '',
    body: markdown.slice(match[0].length).trim(),
  };
}

function parseScalarFrontmatterValue(frontmatter: string, key: string): string | undefined {
  const pattern = new RegExp(`^${key}:\\s*(.+)$`, 'im');
  const match = frontmatter.match(pattern);
  if (!match?.[1]) {
    return undefined;
  }

  const value = match[1].trim().replace(/^["']|["']$/g, '');
  if (value === '|' || value === '>') {
    return undefined;
  }

  return value;
}

function parseNestedFrontmatterValue(frontmatter: string, key: string): string | undefined {
  const pattern = new RegExp(`^\\s+${key}:\\s*(.+)$`, 'im');
  const match = frontmatter.match(pattern);
  if (!match?.[1]) {
    return undefined;
  }

  return match[1].trim().replace(/^["']|["']$/g, '');
}

function parseDescription(frontmatter: string, markdown?: string | null): string | undefined {
  const blockMatch = frontmatter.match(/^description:\s*\|\s*\r?\n([\s\S]*?)(?:\r?\n(?:[A-Za-z0-9_-]+:|[A-Za-z0-9_-]+:\s)|$)/im);
  if (blockMatch?.[1]) {
    return blockMatch[1]
      .split(/\r?\n/)
      .map((line) => line.trim())
      .filter(Boolean)
      .join(' ')
      .trim();
  }

  const scalar = parseScalarFrontmatterValue(frontmatter, 'description');
  if (scalar) {
    return scalar;
  }

  if (!markdown) {
    return undefined;
  }

  const lines = markdown
    .split(/\r?\n/)
    .map((line) => line.trim())
    .filter(Boolean);

  for (const line of lines) {
    if (line.startsWith('#') || line === '---') {
      continue;
    }
    return line.replace(/\s+/g, ' ').trim();
  }

  return undefined;
}

function parseAllowedTools(frontmatter: string): string[] {
  const scalar = parseScalarFrontmatterValue(frontmatter, 'allowed-tools');
  if (!scalar) {
    return [];
  }

  return uniq(scalar.split(','));
}

function parseCategory(frontmatter: string): string | undefined {
  const scalar = parseScalarFrontmatterValue(frontmatter, 'category');
  if (scalar) {
    return scalar;
  }

  const nested = frontmatter.match(/^\s+category:\s*(.+)$/im);
  if (!nested?.[1]) {
    return undefined;
  }

  return nested[1].trim().replace(/^["']|["']$/g, '');
}

function parseFrontmatter(markdown?: string | null): ParsedFrontmatter {
  const { frontmatter } = extractFrontmatter(markdown);
  return {
    name: parseScalarFrontmatterValue(frontmatter, 'name'),
    description: parseDescription(frontmatter, markdown),
    version: parseScalarFrontmatterValue(frontmatter, 'version')
      || parseNestedFrontmatterValue(frontmatter, 'version'),
    category: parseCategory(frontmatter),
    allowedTools: parseAllowedTools(frontmatter),
  };
}

function collectMatches(pattern: RegExp, text: string): string[] {
  const matches: string[] = [];
  const regex = new RegExp(pattern.source, pattern.flags);
  let match: RegExpExecArray | null;

  while ((match = regex.exec(text)) !== null) {
    const value = match.slice(1).find(Boolean) || match[0];
    if (value) {
      matches.push(value);
    }
  }

  return uniq(matches);
}

function detectOperations(text: string): string[] {
  const lowerText = text.toLowerCase();
  const operations = OPERATION_KEYWORDS
    .filter(([, keywords]) => keywords.some((keyword) => lowerText.includes(keyword)))
    .map(([operation]) => operation);

  return operations.length > 0 ? operations : ['assist'];
}

function detectInputExtensions(text: string): string[] {
  return uniq(
    collectMatches(FILE_EXTENSION_PATTERN, text)
      .map((value) => value.toLowerCase())
      .filter((value) => COMMON_FILE_EXTENSIONS.includes(value)),
  );
}

function detectTriggerHints(text: string, inputExtensions: string[]): string[] {
  const quotedHints = collectMatches(QUOTED_TEXT_PATTERN, text)
    .filter((value) => value.length <= 64);

  const sentenceHints = text
    .split(/(?<=[.!?])\s+/)
    .map((sentence) => sentence.trim())
    .filter((sentence) => {
      const lowerSentence = sentence.toLowerCase();
      return lowerSentence.includes('use this skill')
        || lowerSentence.includes('use when')
        || lowerSentence.includes('trigger')
        || lowerSentence.includes('when to use');
    })
    .slice(0, 4)
    .map((sentence) => sentence.replace(/\s+/g, ' ').trim());

  return uniq([...quotedHints, ...sentenceHints, ...inputExtensions]).slice(0, 8);
}

function detectRequiredEnvVars(
  manifestContent: string,
  config?: SkillCapabilityParserInput['config'],
): string[] {
  const fromManifest = collectMatches(ENV_VAR_PATTERN, manifestContent);
  const fromConfig = config?.env ? Object.keys(config.env) : [];
  return uniq([...fromManifest, ...fromConfig]);
}

function isCommandFenceLanguage(value: string): boolean {
  const normalized = value.trim().toLowerCase();
  return normalized === ''
    || ['bash', 'sh', 'shell', 'zsh', 'powershell', 'pwsh', 'ps1', 'cmd', 'bat'].includes(normalized);
}

function normalizeCommandBlockLines(block: string): string[] {
  const lines = block
    .split(/\r?\n/)
    .map((line) => line.trim())
    .filter(Boolean)
    .filter((line) => !line.startsWith('#'));

  const combined: string[] = [];
  for (const line of lines) {
    if (combined.length > 0 && combined[combined.length - 1].endsWith('\\')) {
      combined[combined.length - 1] = `${combined[combined.length - 1].slice(0, -1).trim()} ${line}`;
      continue;
    }

    combined.push(line);
  }

  return combined;
}

function isSafeCommandExample(line: string): boolean {
  const normalized = line.trim();
  if (!normalized) {
    return false;
  }

  if (normalized.startsWith('$ ')) {
    return isSafeCommandExample(normalized.slice(2));
  }

  if (
    normalized.includes('|')
    || normalized.includes('&&')
    || normalized.includes('||')
    || normalized.includes(';')
    || normalized.includes('>$')
    || normalized.includes('$(')
    || normalized.includes('`')
    || normalized.includes('<<')
  ) {
    return false;
  }

  return !/^(curl|wget|brew|apt|apt-get|yum|dnf|pip|pip3|pnpm|npm|yarn)\s+(install|add)\b/i.test(normalized)
    && !/\blogin\b/i.test(normalized)
    && !/\bsetup\b/i.test(normalized);
}

function extractCommandExamples(markdown?: string | null): string[] {
  if (!markdown) {
    return [];
  }

  const examples: string[] = [];
  for (const match of markdown.matchAll(CODE_FENCE_PATTERN)) {
    const language = match[1] || '';
    const block = match[2] || '';
    if (!isCommandFenceLanguage(language)) {
      continue;
    }

    for (const line of normalizeCommandBlockLines(block)) {
      const candidate = line.startsWith('$ ') ? line.slice(2).trim() : line;
      if (!isSafeCommandExample(candidate)) {
        continue;
      }
      examples.push(candidate);
    }
  }

  return uniq(examples).slice(0, 12);
}

function inferCategory(
  parsedCategory: string | undefined,
  operationHints: string[],
  inputExtensions: string[],
): string {
  if (parsedCategory) {
    return parsedCategory;
  }

  if (inputExtensions.some((extension) => SPREADSHEET_EXTENSIONS.includes(extension))) {
    return 'document';
  }

  if (inputExtensions.some((extension) => DOCUMENT_EXTENSIONS.includes(extension))) {
    return 'document';
  }

  if (operationHints.some((operation) => ['search', 'research', 'crawl', 'extract'].includes(operation))) {
    return 'search';
  }

  return 'general';
}

function inferRenderHints(
  category: string,
  operationHints: string[],
  inputExtensions: string[],
  skillKey: string,
): ToolRenderHints {
  if (inputExtensions.some((extension) => SPREADSHEET_EXTENSIONS.includes(extension))) {
    return {
      card: 'document-analysis',
      preferredView: 'table',
      skillType: 'spreadsheet',
      metadata: {
        skillKey,
        operations: operationHints,
      },
    };
  }

  if (inputExtensions.some((extension) => DOCUMENT_EXTENSIONS.includes(extension)) || category === 'document') {
    return {
      card: 'document-analysis',
      preferredView: 'summary',
      skillType: 'document',
      metadata: {
        skillKey,
        operations: operationHints,
        inputExtensions,
      },
    };
  }

  if (category === 'search' || operationHints.some((operation) => ['search', 'research', 'crawl'].includes(operation))) {
    return {
      card: 'search-results',
      preferredView: 'summary',
      skillType: 'search',
      metadata: {
        skillKey,
        operations: operationHints,
      },
    };
  }

  return {
    card: 'generic',
    preferredView: 'summary',
    skillType: category,
    metadata: {
      skillKey,
      operations: operationHints,
    },
  };
}

function truncateDescription(value: string, maxLength = 180): string {
  const normalized = value.replace(/\s+/g, ' ').trim();
  if (normalized.length <= maxLength) {
    return normalized;
  }

  return `${normalized.slice(0, maxLength - 3).trim()}...`;
}

function buildPlannerSummary(
  category: string,
  operationHints: string[],
  inputExtensions: string[],
  description: string,
  requiresAuth: boolean,
): string {
  const segments: string[] = [];

  segments.push(`${category} skill`);

  if (operationHints.length > 0) {
    segments.push(`operations: ${operationHints.join(', ')}`);
  }

  if (inputExtensions.length > 0) {
    segments.push(`inputs: ${inputExtensions.join(', ')}`);
  }

  if (requiresAuth) {
    segments.push('auth/environment required');
  }

  segments.push(truncateDescription(description));

  return segments.join('; ');
}

export function parseSkillCapability(input: SkillCapabilityParserInput): SkillCapability {
  const manifestContent = input.manifestContent?.trim() || '';
  const parsed = parseFrontmatter(manifestContent);
  const config = input.config || {};
  const name = parsed.name || config.name || config.slug || input.skillKey;
  const description = parsed.description || config.description || `Enabled skill ${name}`;
  const combinedText = [description, manifestContent].filter(Boolean).join('\n');
  const operationHints = detectOperations(combinedText);
  const inputExtensions = detectInputExtensions(combinedText);
  const requiredEnvVars = detectRequiredEnvVars(manifestContent, config);
  const commandExamples = extractCommandExamples(manifestContent);
  const requiresAuth = Boolean(config.apiKey)
    || requiredEnvVars.length > 0
    || /requires api key|api key required|authentication required|authorization required|authorize|authorization|login\b|sign in|oauth|access token|bearer token/i.test(combinedText);
  const category = inferCategory(parsed.category, operationHints, inputExtensions);
  const renderHints = inferRenderHints(category, operationHints, inputExtensions, input.skillKey);

  return {
    skillKey: input.skillKey,
    slug: config.slug || input.skillKey,
    name,
    description,
    enabled: config.enabled !== false,
    category,
    version: config.version || parsed.version,
    source: config.source,
    baseDir: config.baseDir,
    manifestPath: config.filePath,
    allowedTools: uniq(parsed.allowedTools),
    operationHints,
    triggerHints: detectTriggerHints(combinedText, inputExtensions),
    inputExtensions,
    requiredEnvVars,
    requiresAuth,
    commandExamples,
    plannerSummary: buildPlannerSummary(
      category,
      operationHints,
      inputExtensions,
      description,
      requiresAuth,
    ),
    renderHints,
  };
}