// user-data.mjs — Spor C fase C2.1: user-owned storage + ambient org context.
//
// This module is a PURE RESOLVER. It NEVER writes and never spawns anything —
// it only resolves user-owned paths and builds a compact, deterministic
// summary from file contents it is HANDED (no fs read of its own). All org-/
// config writing happens elsewhere, gated, via lib/atomic-write + lib/backup.
//
// Why a user-owned dir? Org context + the C1 scheduler config previously lived
// inside the plugin directory (gitignored), so a plugin reinstall / marketplace
// move blew them away. Resolving them under ~/.claude/ms-ai-architect/ — a
// sibling of ~/.claude/plugins/, independent of pluginRoot — makes them survive
// reinstall (acceptance K2). Privacy is preserved: this path is in no git repo.
//
// Zero dependencies beyond node:os/path. Every function is pure.

import { homedir } from 'node:os';
import { join } from 'node:path';

// The plugin's folder under ~/.claude/ (sibling of ~/.claude/plugins/).
export const USER_DATA_DIRNAME = 'ms-ai-architect';

// The scheduler config filename. Single source of truth shared with
// detection-schedule.mjs (C1) so loadScheduleConfig stays backward-compatible.
export const CONFIG_FILENAME = 'ms-ai-architect.local.md';

// The five structured onboarding files, in the order they are surfaced.
export const ORG_FILES = Object.freeze([
  'organization-profile.md',
  'technology-stack.md',
  'security-compliance.md',
  'architecture-decisions.md',
  'business-references.md',
]);

// The optional free-prose file (C2.2, #3): "everything else you want the plugin
// to know". Deliberately NOT in ORG_FILES — its presence is optional and must
// NOT affect the onboarding-completeness count (the SessionStart hook gates that
// on `count < ORG_FILES.length`). It is read for the ambient summary only.
export const FREE_CONTEXT_FILE = 'free-context.md';

const FREE_CONTEXT_LABEL = 'Fri kontekst';

const DEFAULT_SUMMARY_CAP = 25; // max summary lines (hook-injection budget)
const DEFAULT_MAX_VALUE_LEN = 160; // per-field char cap (free-text guard)

/** The user-owned data root: ~/.claude/ms-ai-architect/ (survives reinstall). */
export function resolveUserDataDir(home = homedir()) {
  return join(home, '.claude', USER_DATA_DIRNAME);
}

/** The user-owned org/ directory (the five structured onboarding files). */
export function resolveOrgDir(home = homedir()) {
  return join(resolveUserDataDir(home), 'org');
}

/** The user-owned scheduler config path (same filename as the C1 plugin-root one). */
export function resolveConfigPath(home = homedir()) {
  return join(resolveUserDataDir(home), CONFIG_FILENAME);
}

/** Drop a leading `---`…`---` YAML frontmatter block, if present. */
function stripFrontmatter(text) {
  if (!text.startsWith('---')) return text;
  const m = text.match(/^---\n[\s\S]*?\n---\n?/);
  return m ? text.slice(m[0].length) : text;
}

/**
 * Extract `## Header` → collapsed-body pairs from one org file's markdown.
 * Frontmatter and the leading H1 are ignored; H2 sections with an empty body
 * are skipped. Body lines are collapsed to a single spaced line. Pure.
 * @param {string} content
 * @returns {Array<[string, string]>}
 */
function extractSections(content) {
  const lines = stripFrontmatter(content).split('\n');
  const out = [];
  let header = null;
  let body = [];
  const flush = () => {
    if (header !== null) {
      const value = body.join(' ').replace(/\s+/g, ' ').trim();
      if (value) out.push([header, value]);
    }
  };
  for (const line of lines) {
    const h2 = line.match(/^##\s+(.+?)\s*$/);
    if (h2) {
      flush();
      header = h2[1];
      body = [];
    } else if (header !== null && !/^#\s/.test(line)) {
      body.push(line);
    }
  }
  flush();
  return out;
}

/**
 * Collapse a markdown document to one prose line: drop frontmatter and every
 * header line, then squeeze whitespace. Used for the free-context file, which is
 * ONE free field (not structured H2 sections) and may be plain prose — so it is
 * surfaced whole rather than per-section, never silently dropped. Pure.
 * @param {string} content
 * @returns {string}
 */
function collapseProse(content) {
  return stripFrontmatter(content)
    .split('\n')
    .filter((line) => !/^#{1,6}\s/.test(line))
    .join(' ')
    .replace(/\s+/g, ' ')
    .trim();
}

/** Truncate a field value to maxValueLen, appending an ellipsis when cut. Pure. */
function capValue(value, maxValueLen) {
  return value.length > maxValueLen
    ? `${value.slice(0, maxValueLen - 1).trimEnd()}…`
    : value;
}

/**
 * Build a compact, deterministic org-context summary from org file contents.
 * PURE — takes a `{ filename: contentString }` map (the caller reads the files)
 * and returns a length-capped `Header: value` block, one field per line, in
 * ORG_FILES order then header order. Empty/garbage input => "".
 *
 * Robust by design: it extracts whatever H2 sections the onboarding agent
 * wrote rather than hard-coding field names, so header wording can drift
 * without silently emptying the summary.
 *
 * @param {Record<string, string|null>|null|undefined} orgFiles
 * @param {{cap?: number, maxValueLen?: number}} [opts]
 * @returns {string}
 */
export function buildOrgSummary(orgFiles, opts = {}) {
  if (!orgFiles || typeof orgFiles !== 'object') return '';
  const cap = opts.cap ?? DEFAULT_SUMMARY_CAP;
  const maxValueLen = opts.maxValueLen ?? DEFAULT_MAX_VALUE_LEN;

  const fields = [];
  for (const name of ORG_FILES) {
    const content = orgFiles[name];
    if (typeof content !== 'string' || !content.trim()) continue;
    for (const [header, value] of extractSections(content)) {
      fields.push(`${header}: ${capValue(value, maxValueLen)}`);
    }
  }

  // Free-prose context (C2.2, #3): the optional sixth file, surfaced LAST as one
  // "Fri kontekst" field regardless of internal markdown structure, so a plain
  // paragraph is never silently dropped (acceptance K3). Capped like any field.
  const freeContent = orgFiles[FREE_CONTEXT_FILE];
  if (typeof freeContent === 'string' && freeContent.trim()) {
    const body = collapseProse(freeContent);
    if (body) fields.push(`${FREE_CONTEXT_LABEL}: ${capValue(body, maxValueLen)}`);
  }

  if (fields.length === 0) return '';
  if (fields.length <= cap) return fields.join('\n');

  // Over budget: keep (cap-1) fields, then a marker line for the omitted rest.
  const kept = fields.slice(0, cap - 1);
  kept.push(`… (+${fields.length - kept.length} flere felt)`);
  return kept.join('\n');
}