// Copyright (C) 2025 Keygraph, Inc.
//
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU Affero General Public License version 3
// as published by the Free Software Foundation.

import { fs, path } from 'zx';
import { PROMPTS_DIR } from '../paths.js';
import { PLAYWRIGHT_SESSION_MAPPING } from '../session-manager.js';
import type { ActivityLogger } from '../types/activity-logger.js';
import type { Authentication, DistributedConfig, DistributedReportConfig, Rule, VulnClass } from '../types/config.js';
import { isGlobPattern } from '../utils/glob.js';
import { handlePromptError, PentestError } from './error-handling.js';

function renderRuleLine(tag: string, value: string, description?: string): string {
  const base = `- ${tag} ${value}`;
  return description ? `${base} - ${description}` : base;
}

function renderUrlRules(rules: Rule[]): string {
  if (rules.length === 0) return 'None';
  return rules.map((r) => renderRuleLine(`[${r.type.toUpperCase()}]`, r.value, r.description)).join('\n');
}

function renderCodePathRules(rules: Rule[]): string {
  const filtered = rules.filter((r) => r.type === 'code_path');
  if (filtered.length === 0) return 'None';
  return filtered
    .map((r) => renderRuleLine(isGlobPattern(r.value) ? '[GLOB]' : '[FILE]', r.value, r.description))
    .join('\n');
}

const VULN_CLASS_HEADINGS: Record<VulnClass, string> = {
  auth: 'Authentication Vulnerabilities',
  authz: 'Authorization Vulnerabilities',
  xss: 'Cross-Site Scripting (XSS) Vulnerabilities',
  injection: 'SQL/Command Injection Vulnerabilities',
  ssrf: 'Server-Side Request Forgery (SSRF) Vulnerabilities',
};

/**
 * Renders the <not_assessed_classes> block. Empty when every class completed.
 *
 * A class whose analysis failed was never assessed, so the report must not present its
 * absence of findings as a clean result. The block is authoritative for that caveat.
 */
function renderNotAssessedClassesBlock(failed: readonly VulnClass[] = []): string {
  if (failed.length === 0) {
    return '';
  }

  const classes = [...new Set(failed)];
  const lines: string[] = [
    '<not_assessed_classes>',
    'The following vulnerability classes did not complete and were NOT assessed in this run. Treat this list as authoritative for completeness caveats.',
    '',
  ];

  for (const cls of classes) {
    lines.push(
      `- ${VULN_CLASS_HEADINGS[cls]}: analysis did not complete; this class was NOT assessed. Absence of findings here does not indicate the class is clean.`,
    );
  }

  lines.push(
    '',
    'When writing report_meta.executive_summary, scope any no-findings statement to the classes that were assessed and mention these not-assessed classes. Do not state or imply that the target is clean for these classes.',
    '</not_assessed_classes>',
  );
  return lines.join('\n');
}

/**
 * Which configured filters this run can actually enforce.
 *
 * Every finding carries `severity` (see ../collectors/finding-collector.ts), so a severity
 * threshold always applies. `confidence` exists only on an analysed finding — handing an
 * exploit run a confidence threshold is a directive it cannot honor.
 */
function applicableFilters(report: DistributedReportConfig | undefined, exploitEnabled: boolean) {
  return {
    severity: Boolean(report?.min_severity),
    confidence: Boolean(report?.min_confidence) && !exploitEnabled,
    guidance: Boolean(report?.guidance?.trim()),
  };
}

/**
 * Renders the top-level <report_filters> block. Empty when no filters are set —
 * each filter is included only when the operator configured it, so the agent
 * never sees `none` placeholders or instructions for filters that don't apply.
 */
function renderReportFiltersBlock(report: DistributedReportConfig | undefined, exploitEnabled: boolean): string {
  if (!report) return '';
  const guidance = report.guidance?.trim();
  const applies = applicableFilters(report, exploitEnabled);
  if (!applies.severity && !applies.confidence && !applies.guidance) return '';

  const lines: string[] = [
    '<report_filters>',
    'The filters below are user-supplied and binding for this assessment. Honor each strictly when assembling the final report.',
    '',
  ];
  if (applies.severity) {
    lines.push(
      `- Minimum severity: ${report.min_severity} — keep only findings rated this severity or higher (scale: low < medium < high < critical).`,
    );
  }
  if (applies.confidence) {
    lines.push(
      `- Minimum confidence: ${report.min_confidence} — keep only findings rated this confidence or higher (scale: low < medium < high).`,
    );
  }
  if (guidance) {
    lines.push('');
    lines.push('User guidance — apply throughout the report as binding directives for finding selection:');
    lines.push(guidance);
  }
  lines.push('</report_filters>');
  return lines.join('\n');
}

/**
 * Renders the per-finding DROP rules used inside the cleanup step. Severity and
 * confidence inline as concrete thresholds; guidance is referenced by pointer
 * so the actual text only lives in <report_filters>, avoiding double-statement.
 */
function renderReportFilterRules(report: DistributedReportConfig | undefined, exploitEnabled: boolean): string {
  const applies = applicableFilters(report, exploitEnabled);
  const drops: string[] = [];
  if (applies.severity) drops.push(`* severity is below ${report?.min_severity}`);
  if (applies.confidence) drops.push(`* confidence is below ${report?.min_confidence}`);
  if (report?.guidance?.trim()) drops.push('* topic matches an exclusion in the user guidance');
  if (drops.length === 0) return '';
  return ['   - DROP any `### [TYPE]-VULN-[NUMBER]` finding whose:', ...drops.map((d) => `     ${d}`)].join('\n');
}

interface PromptVariables {
  webUrl: string;
  repoPath: string;
  /** Classes whose analysis did not complete, so the report can mark them not assessed. */
  failedClasses?: readonly VulnClass[];
  AUTH_STATE_FILE: string;
  PLAYWRIGHT_SESSION?: string;
}

interface IncludeReplacement {
  placeholder: string;
  content: string;
}

// Pure function: Build complete login instructions from config
async function buildLoginInstructions(
  authentication: Authentication,
  logger: ActivityLogger,
  promptsBaseDir: string = PROMPTS_DIR,
): Promise<string> {
  try {
    // 1. Load the login instructions template
    const loginInstructionsPath = path.join(promptsBaseDir, 'shared', 'login-instructions.txt');

    if (!(await fs.pathExists(loginInstructionsPath))) {
      throw new PentestError('Login instructions template not found', 'filesystem', false, { loginInstructionsPath });
    }

    const fullTemplate = await fs.readFile(loginInstructionsPath, 'utf8');

    const getSection = (content: string, sectionName: string): string => {
      const regex = new RegExp(`<!-- BEGIN:${sectionName} -->([\\s\\S]*?)<!-- END:${sectionName} -->`, 'g');
      const match = regex.exec(content);
      return match?.[1]?.trim() ?? '';
    };

    // 2. Extract sections based on login type
    const loginType = authentication.login_type?.toUpperCase();
    let loginInstructions = '';

    const commonSection = getSection(fullTemplate, 'COMMON');
    const authSection = loginType ? getSection(fullTemplate, loginType) : ''; // FORM or SSO
    const verificationSection = getSection(fullTemplate, 'VERIFICATION');

    // 3. Assemble instructions from sections (fallback to full template if markers missing)
    if (!commonSection && !authSection && !verificationSection) {
      logger.warn('Section markers not found, using full login instructions template');
      loginInstructions = fullTemplate;
    } else {
      loginInstructions = [commonSection, authSection, verificationSection].filter((section) => section).join('\n\n');
    }

    // 4. Interpolate login flow and credential placeholders
    let userInstructions = (authentication.login_flow ?? []).join('\n');

    if (authentication.credentials) {
      if (authentication.credentials.username) {
        userInstructions = replaceLiteral(userInstructions, /\$username/g, authentication.credentials.username);
      }
      if (authentication.credentials.password) {
        userInstructions = replaceLiteral(userInstructions, /\$password/g, authentication.credentials.password);
      }
      if (authentication.credentials.totp_secret) {
        userInstructions = replaceLiteral(
          userInstructions,
          /\$totp/g,
          `generated TOTP code using secret "${authentication.credentials.totp_secret}"`,
        );
      }
      if (authentication.credentials.email_login?.address) {
        userInstructions = replaceLiteral(
          userInstructions,
          /\$email_address/g,
          authentication.credentials.email_login.address,
        );
      }
      if (authentication.credentials.email_login?.password) {
        userInstructions = replaceLiteral(
          userInstructions,
          /\$email_password/g,
          authentication.credentials.email_login.password,
        );
      }
      if (authentication.credentials.email_login?.totp_secret) {
        userInstructions = replaceLiteral(
          userInstructions,
          /\$email_totp/g,
          `generated TOTP code using secret "${authentication.credentials.email_login.totp_secret}"`,
        );
      }
    }

    loginInstructions = replaceLiteral(loginInstructions, /{{user_instructions}}/g, userInstructions);

    // 5. Replace TOTP secret placeholder if present in template
    if (authentication.credentials?.totp_secret) {
      loginInstructions = replaceLiteral(loginInstructions, /{{totp_secret}}/g, authentication.credentials.totp_secret);
    }

    return loginInstructions;
  } catch (error) {
    if (error instanceof PentestError) {
      throw error;
    }
    const errMsg = error instanceof Error ? error.message : String(error);
    throw new PentestError(`Failed to build login instructions: ${errMsg}`, 'config', false, {
      authentication,
      originalError: errMsg,
    });
  }
}

// Pure function: Process @include() directives
async function processIncludes(content: string, baseDir: string): Promise<string> {
  const includeRegex = /@include\(([^)]+)\)/g;
  const resolvedBase = path.resolve(baseDir);

  const replacements: IncludeReplacement[] = await Promise.all(
    Array.from(content.matchAll(includeRegex)).map(async (match) => {
      const rawPath = match[1] ?? '';
      const includePath = path.resolve(baseDir, rawPath);
      if (!includePath.startsWith(resolvedBase + path.sep) && includePath !== resolvedBase) {
        throw new PentestError(`Path traversal detected in @include(): ${rawPath}`, 'prompt', false, {
          includePath,
          baseDir: resolvedBase,
        });
      }
      const sharedContent = await fs.readFile(includePath, 'utf8');
      return {
        placeholder: match[0],
        content: sharedContent,
      };
    }),
  );

  for (const replacement of replacements) {
    content = replaceLiteral(content, replacement.placeholder, replacement.content);
  }
  return content;
}

/**
 * Replaces `pattern` with `replacement` treating the replacement as a literal
 * string. Native `String.replace` interprets `$&`, `$1`, `$$` in the replacement
 * as special patterns, which mangles credential and config values that legitimately
 * contain `$`. The function form of `replace` bypasses that interpretation.
 */
function replaceLiteral(input: string, pattern: RegExp | string, replacement: string): string {
  return input.replace(pattern, () => replacement);
}

function buildAuthContext(config: DistributedConfig | null): string {
  if (!config?.authentication) {
    return 'No authentication configured - unauthenticated testing only';
  }

  const auth = config.authentication;
  const lines = [
    `- Login type: ${auth.login_type.toUpperCase()}`,
    `- Username: ${auth.credentials.username}`,
    `- Login URL: ${auth.login_url}`,
  ];

  if (auth.credentials?.totp_secret) {
    lines.push('- MFA: TOTP enabled');
  }

  return lines.join('\n');
}

// Pure function: Variable interpolation
async function interpolateVariables(
  template: string,
  variables: PromptVariables,
  config: DistributedConfig | null = null,
  logger: ActivityLogger,
  promptsBaseDir: string = PROMPTS_DIR,
): Promise<string> {
  try {
    if (!template || typeof template !== 'string') {
      throw new PentestError('Template must be a non-empty string', 'validation', false, {
        templateType: typeof template,
        templateLength: template?.length,
      });
    }

    if (!variables || !variables.webUrl || !variables.repoPath) {
      throw new PentestError('Variables must include webUrl and repoPath', 'validation', false, {
        variables: Object.keys(variables || {}),
      });
    }

    // replaceLiteral is used for all value insertions so config values that
    // contain `$&`/`$$`/`$1`/etc. aren't mangled as replacement patterns.
    let result = template;
    result = replaceLiteral(result, /{{WEB_URL}}/g, variables.webUrl);
    result = replaceLiteral(result, /{{REPO_PATH}}/g, variables.repoPath);
    result = replaceLiteral(result, /{{PLAYWRIGHT_SESSION}}/g, variables.PLAYWRIGHT_SESSION || 'agent1');
    result = replaceLiteral(result, /{{AUTH_CONTEXT}}/g, buildAuthContext(config));
    result = replaceLiteral(
      result,
      /{{DESCRIPTION}}/g,
      config?.description ? `Description: ${config.description}` : '',
    );

    const avoidUrlRules = config?.avoid?.filter((r) => r.type !== 'code_path') ?? [];
    const focusUrlRules = config?.focus?.filter((r) => r.type !== 'code_path') ?? [];
    if (avoidUrlRules.length === 0 && focusUrlRules.length === 0) {
      result = result.replace(/<rules>[\s\S]*?<\/rules>\s*/g, '');
    } else {
      const avoidStr = renderUrlRules(avoidUrlRules);
      const focusStr = renderUrlRules(focusUrlRules);
      result = replaceLiteral(result, /{{RULES_AVOID}}/g, avoidStr);
      result = replaceLiteral(result, /{{RULES_FOCUS}}/g, focusStr);
    }

    const avoidCodeRules = (config?.avoid ?? []).filter((r) => r.type === 'code_path');
    const focusCodeRules = (config?.focus ?? []).filter((r) => r.type === 'code_path');
    if (avoidCodeRules.length === 0 && focusCodeRules.length === 0) {
      result = result.replace(/<code_path_rules>[\s\S]*?<\/code_path_rules>\s*/g, '');
    } else {
      result = replaceLiteral(result, /{{CODE_RULES_AVOID}}/g, renderCodePathRules(config?.avoid ?? []));
      result = replaceLiteral(result, /{{CODE_RULES_FOCUS}}/g, renderCodePathRules(config?.focus ?? []));
    }

    const roe = config?.rules_of_engagement?.trim() ?? '';
    if (roe) {
      result = replaceLiteral(result, /{{RULES_OF_ENGAGEMENT}}/g, roe);
    } else {
      result = result.replace(/<rules_of_engagement>[\s\S]*?<\/rules_of_engagement>\s*/g, '');
    }

    if (!config?.authentication) {
      result = result.replace(/<shared_authenticated_session>[\s\S]*?<\/shared_authenticated_session>\s*/g, '');
    } else {
      result = replaceLiteral(result, /{{AUTH_STATE_FILE}}/g, variables.AUTH_STATE_FILE);
    }

    if (config?.authentication?.login_flow) {
      const loginInstructions = await buildLoginInstructions(config.authentication, logger, promptsBaseDir);
      result = replaceLiteral(result, /{{LOGIN_INSTRUCTIONS}}/g, loginInstructions);
    } else {
      result = result.replace(/{{LOGIN_INSTRUCTIONS}}/g, '');
    }

    const vulnClasses = config?.vuln_classes ?? [];
    result = replaceLiteral(
      result,
      /{{VULN_CLASSES_TESTED}}/g,
      vulnClasses.length > 0 ? vulnClasses.join(', ') : 'injection, xss, auth, authz, ssrf',
    );
    result = replaceLiteral(
      result,
      /{{NOT_ASSESSED_CLASSES}}/g,
      renderNotAssessedClassesBlock(variables.failedClasses ?? []),
    );

    const exploitEnabled = config?.exploit ?? true;

    // Drop every block belonging to the mode this run is not in, so the prompt never documents
    // a field the tool would reject. The backreference pins each match to a closed pair.
    const droppedMode = exploitEnabled ? 'analysis' : 'exploit';
    result = result.replace(new RegExp(`<(${droppedMode}_mode_[a-z_]+)>[\\s\\S]*?</\\1>\\n?`, 'g'), '');
    result = result.replace(/<\/?(?:exploit|analysis)_mode_[a-z_]+>\n?/g, '');

    result = replaceLiteral(result, /{{EXPLOITATION}}/g, exploitEnabled ? 'enabled' : 'disabled');
    result = replaceLiteral(
      result,
      /{{REPORT_VULN_SUBHEADING}}/g,
      exploitEnabled ? 'Successfully Exploited Vulnerabilities' : 'Identified Vulnerabilities',
    );

    if (config?.report?.min_confidence && exploitEnabled) {
      logger.warn(
        `report.min_confidence="${config.report.min_confidence}" is ignored when exploit=true: an ` +
          'exploited finding is rated by severity, not confidence. Use report.min_severity.',
      );
    }
    result = replaceLiteral(
      result,
      /{{REPORT_FILTERS_BLOCK}}/g,
      renderReportFiltersBlock(config?.report, exploitEnabled),
    );
    result = replaceLiteral(
      result,
      /{{REPORT_FILTER_RULES}}/g,
      renderReportFilterRules(config?.report, exploitEnabled),
    );

    // Collapse runs of 3+ newlines (left behind by tag-strip and empty-fragment substitutions).
    result = result.replace(/\n{3,}/g, '\n\n');

    // Validate that all placeholders have been replaced (excluding instructional text)
    const remainingPlaceholders = result.match(/\{\{[^}]+\}\}/g);
    if (remainingPlaceholders) {
      logger.warn(`Found unresolved placeholders in prompt: ${remainingPlaceholders.join(', ')}`);
    }

    return result;
  } catch (error) {
    if (error instanceof PentestError) {
      throw error;
    }
    const errMsg = error instanceof Error ? error.message : String(error);
    throw new PentestError(`Variable interpolation failed: ${errMsg}`, 'prompt', false, { originalError: errMsg });
  }
}

// Resolve promptDir override against SHANNON_WORKER_ROOT so relative paths
// from callers stay cwd-independent.
function resolvePromptDir(promptDir: string | undefined): string {
  if (!promptDir) return PROMPTS_DIR;
  if (path.isAbsolute(promptDir)) return promptDir;
  return path.resolve(process.env.SHANNON_WORKER_ROOT ?? process.cwd(), promptDir);
}

// Pure function: Load and interpolate prompt template
export async function loadPrompt(
  promptName: string,
  variables: PromptVariables,
  config: DistributedConfig | null = null,
  pipelineTestingMode: boolean = false,
  logger: ActivityLogger,
  promptDir?: string,
): Promise<string> {
  try {
    const basePromptsDir = resolvePromptDir(promptDir);
    const promptsDir = pipelineTestingMode ? path.join(basePromptsDir, 'pipeline-testing') : basePromptsDir;
    const promptPath = path.join(promptsDir, `${promptName}.txt`);

    if (pipelineTestingMode) {
      logger.info(`Using pipeline testing prompt: ${promptPath}`);
    }

    if (!(await fs.pathExists(promptPath))) {
      throw new PentestError(`Prompt file not found: ${promptPath}`, 'prompt', false, { promptName, promptPath });
    }

    // 2. Assign Playwright session based on agent name
    const enhancedVariables: PromptVariables = { ...variables };

    const session = PLAYWRIGHT_SESSION_MAPPING[promptName as keyof typeof PLAYWRIGHT_SESSION_MAPPING];
    if (session) {
      enhancedVariables.PLAYWRIGHT_SESSION = session;
      logger.info(`Assigned ${promptName} -> ${enhancedVariables.PLAYWRIGHT_SESSION}`);
    } else {
      enhancedVariables.PLAYWRIGHT_SESSION = 'agent1';
      logger.warn(`Unknown agent ${promptName}, using fallback -> ${enhancedVariables.PLAYWRIGHT_SESSION}`);
    }

    // 3. Read template file
    let template = await fs.readFile(promptPath, 'utf8');

    // 4. Process @include directives
    template = await processIncludes(template, promptsDir);

    // 5. Interpolate variables and return final prompt
    return await interpolateVariables(template, enhancedVariables, config, logger, basePromptsDir);
  } catch (error) {
    if (error instanceof PentestError) {
      throw error;
    }
    const promptError = handlePromptError(promptName, error as Error);
    throw promptError.error;
  }
}