/**
 * @file A workspace's own context, like a Claude Desktop project's: its
 * Instructions (`lanes.instructions`), extra Folders and uploaded Context files
 * (`lane_sources`), its read-only Memory, and what all of it adds to a pane at
 * spawn (`launchExtras`). Everything a spawn reads comes from these rows, never
 * from a request. An extra folder must exist, be a directory, not be the
 * workspace's own folder and not be or contain the OS home; an uploaded file
 * is stored by AgentHub under `<data dir>/workspace-context/<laneId>/` with a
 * name it chooses, so a request never names a path on disk. Only Claude
 * (`--add-dir`, the instructions as a CLAUDE.md in a folder of their own) and Codex (`--add-dir`,
 * `-c developer_instructions=`) can take them; every other tool is reported
 * unsupported and its panes get nothing. The workspace OWNER's own agent
 * instructions (`user_prefs.instructions`, Settings → My agent instructions)
 * go first, before the workspace's.
 * @author Nguyễn Ngọc Trí Vĩ <vinnt@smartgift.vn>
 */
"use strict";

const fs = require("fs");
const path = require("path");
const crypto = require("crypto");
const { db } = require("../db");
const { getDataDir, getClaudeHome, encodeCwd } = require("./claude-home");
const { validateHomeDir } = require("./settings-env");

const SUPPORTED_TOOLS = new Set(["claude", "codex"]);
const MAX_INSTRUCTIONS = 16_000;
const MAX_FILE_BYTES = 10 * 1024 * 1024;
const MAX_SOURCES = 50;
const MAX_MEMORY_BYTES = 256 * 1024;
// The whole `tmux new-session … -- argv` must fit in one tmux message (16 KB
// on tmux 3.4, `command too long` past it), with PATH and the env beside it.
// Claude reads the prompt from a file instead; Codex has no file form for
// developer instructions, so past this it gets a pointer to the file.
const INLINE_PROMPT_BYTES = 6 * 1024;

const fail = (code, message) => Object.assign(new Error(message), { code });

function laneRow(laneId) {
  const lane = db.prepare("SELECT id, cwd, tool, instructions FROM lanes WHERE id = ?").get(laneId);
  if (!lane) throw fail("ENOLANE", "workspace not found");
  return lane;
}

function contextRoot() {
  return path.join(getDataDir(), "workspace-context");
}

function contextDir(laneId) {
  return path.join(contextRoot(), String(Number(laneId)));
}

function supports(tool) {
  return SUPPORTED_TOOLS.has(tool || "claude");
}

function listSources(laneId) {
  laneRow(laneId);
  return db
    .prepare(
      "SELECT id, kind, path, name, size, added_at FROM lane_sources WHERE lane_id = ? ORDER BY id ASC"
    )
    .all(laneId)
    .map((r) => ({ ...r, missing: !fs.existsSync(r.path) }));
}

function assertRoom(laneId) {
  const count = db
    .prepare("SELECT count(*) AS c FROM lane_sources WHERE lane_id = ?")
    .get(laneId).c;
  if (count >= MAX_SOURCES)
    throw fail("ETOOMANY", `a workspace holds at most ${MAX_SOURCES} sources`);
}

function insertSource(laneId, kind, p, name, size) {
  assertRoom(laneId);
  const info = db
    .prepare(
      "INSERT INTO lane_sources (lane_id, kind, path, name, size, added_at) VALUES (?, ?, ?, ?, ?, ?)"
    )
    .run(laneId, kind, p, name, size ?? null, new Date().toISOString());
  return db.prepare("SELECT * FROM lane_sources WHERE id = ?").get(info.lastInsertRowid);
}

/** `allowed(realPath)`: the caller's own boundary (a developer's home). */
function addFolder(laneId, input, { allowed = () => true } = {}) {
  const lane = laneRow(laneId);
  if (typeof input !== "string" || !input.trim()) throw fail("EBADPATH", "path is required");
  let resolved;
  try {
    resolved = fs.realpathSync(validateHomeDir("a workspace folder", input));
  } catch (err) {
    if (err.code === "EBADHOME") throw err;
    throw fail("EBADPATH", err.message);
  }
  let laneCwd = lane.cwd;
  try {
    laneCwd = fs.realpathSync(lane.cwd);
  } catch {
    /* a vanished workspace folder still has its recorded path */
  }
  if (!allowed(resolved)) throw fail("EFOLDER", "an extra folder must be inside your own folder");
  if (resolved === laneCwd) throw fail("EDUP", "that is the workspace's own folder");
  const dup = db
    .prepare("SELECT 1 FROM lane_sources WHERE lane_id = ? AND kind = 'folder' AND path = ?")
    .get(laneId, resolved);
  if (dup) throw fail("EDUP", "that folder is already a source");
  return insertSource(laneId, "folder", resolved, path.basename(resolved) || resolved, null);
}

/**
 * An extra folder's directory for the git routes (`?source=<id>`): only a
 * `folder` row of THIS workspace that is still a directory — the request names
 * a row id, never a path.
 * @throws ENOSOURCE otherwise.
 */
function sourceFolder(laneId, sourceId) {
  const row = /^\d+$/.test(String(sourceId))
    ? db
        .prepare("SELECT path FROM lane_sources WHERE id = ? AND lane_id = ? AND kind = 'folder'")
        .get(Number(sourceId), laneId)
    : null;
  let dir = null;
  try {
    dir = row && fs.statSync(row.path).isDirectory() ? fs.realpathSync(row.path) : null;
  } catch {
    /* gone since it was added */
  }
  if (!dir) throw fail("ENOSOURCE", "that folder is not one of this workspace's folders");
  return dir;
}

/** A file name AgentHub can store: no directory part, no control or path characters. */
function safeName(raw) {
  const base = path.basename(String(raw || "")).replace(/[^\p{L}\p{N}._ -]/gu, "_");
  const trimmed = base
    .replace(/^[.\s]+/, "")
    .trim()
    .slice(0, 120);
  return trimmed || "file";
}

function addFile(laneId, rawName, buf) {
  laneRow(laneId);
  if (!Buffer.isBuffer(buf) || buf.length === 0) throw fail("EEMPTY", "the file is empty");
  if (buf.length > MAX_FILE_BYTES) {
    throw fail("ETOOBIG", `a context file may be at most ${MAX_FILE_BYTES / 1024 / 1024} MB`);
  }
  // Before the write: a refused upload must leave nothing in the dir the
  // agent is handed as --add-dir.
  assertRoom(laneId);
  const dir = contextDir(laneId);
  fs.mkdirSync(dir, { recursive: true, mode: 0o700 });
  const name = safeName(rawName);
  const ext = path.extname(name);
  const stem = name.slice(0, name.length - ext.length);
  let file = path.join(dir, name);
  for (let n = 2; fs.existsSync(file); n++) {
    const tag = n <= 99 ? `(${n})` : crypto.randomBytes(4).toString("hex");
    file = path.join(dir, `${stem} ${tag}${ext}`);
  }
  fs.writeFileSync(file, buf, { mode: 0o600, flag: "wx" });
  return insertSource(laneId, "file", file, path.basename(file), buf.length);
}

/** True when `p` is inside AgentHub's own context store — the only files it may delete. */
function ownsFile(p) {
  const root = contextRoot() + path.sep;
  return path.resolve(p).startsWith(root);
}

function removeSource(laneId, sourceId) {
  laneRow(laneId);
  const row = db
    .prepare("SELECT * FROM lane_sources WHERE id = ? AND lane_id = ?")
    .get(Number(sourceId), laneId);
  if (!row) throw fail("ENOSOURCE", "source not found");
  // A folder is the user's; only AgentHub's own copy of an uploaded file goes.
  if (row.kind === "file" && ownsFile(row.path)) fs.rmSync(row.path, { force: true });
  db.prepare("DELETE FROM lane_sources WHERE id = ?").run(row.id);
}

/** Drops AgentHub's context copies of a deleted workspace (its rows cascade). */
function removeLaneContext(laneId) {
  const dir = contextDir(laneId);
  if (ownsFile(dir)) fs.rmSync(dir, { recursive: true, force: true });
  const prompts = path.join(getDataDir(), "workspace-prompts");
  fs.rmSync(path.join(prompts, String(Number(laneId))), { recursive: true, force: true });
  fs.rmSync(path.join(prompts, `${Number(laneId)}.md`), { force: true }); // before v2.8.9
}

/** Instructions text as stored: a string of at most MAX_INSTRUCTIONS, blank ⇒ null. */
function cleanInstructions(text) {
  if (text !== null && typeof text !== "string") {
    throw fail("EBADFIELD", "instructions must be a string or null");
  }
  const value = text === null || !text.trim() ? null : text.replace(/\r\n/g, "\n");
  if (value && value.length > MAX_INSTRUCTIONS) {
    throw fail("ETOOBIG", `instructions may be at most ${MAX_INSTRUCTIONS} characters`);
  }
  return value;
}

function setInstructions(laneId, text) {
  laneRow(laneId);
  const value = cleanInstructions(text);
  db.prepare("UPDATE lanes SET instructions = ? WHERE id = ?").run(value, laneId);
}

function setUserInstructions(userKey, text) {
  const value = cleanInstructions(text);
  db.prepare(
    `INSERT INTO user_prefs (user_key, instructions) VALUES (?, ?)
     ON CONFLICT(user_key) DO UPDATE SET instructions = excluded.instructions,
       updated_at = strftime('%Y-%m-%dT%H:%M:%fZ', 'now')`
  ).run(userKey, value);
}

function getUserInstructions(userKey) {
  return (
    db.prepare("SELECT instructions FROM user_prefs WHERE user_key = ?").get(userKey)
      ?.instructions || null
  );
}

/** The owner's own instructions: `local` in local mode, `u<owner_id>` in server mode. */
function ownerInstructions(ownerId) {
  if (!require("./auth").isServerMode()) return getUserInstructions("local");
  return ownerId ? getUserInstructions(`u${ownerId}`) : null;
}

/**
 * What a pane of this workspace is started with, read from its rows: the
 * extra folders and (when any file was uploaded) the context dir to allow, and
 * the text to append to the system prompt — the instructions, then the list of
 * context files so the agent knows they exist. Sources that vanished are
 * skipped, not fatal: a deleted folder must not stop the workspace starting.
 */
function launchExtras(laneId, tool) {
  const empty = { addDirs: [], systemPrompt: null, systemPromptFile: null };
  if (!supports(tool)) return empty;
  const lane = db.prepare("SELECT instructions, owner_id FROM lanes WHERE id = ?").get(laneId);
  if (!lane) return empty;
  const rows = db
    .prepare("SELECT kind, path FROM lane_sources WHERE lane_id = ? ORDER BY id ASC")
    .all(laneId);
  const isDir = (p) => {
    try {
      return fs.statSync(p).isDirectory();
    } catch {
      return false;
    }
  };
  const folders = rows.filter((r) => r.kind === "folder" && isDir(r.path)).map((r) => r.path);
  let files = rows.filter((r) => r.kind === "file" && fs.existsSync(r.path)).map((r) => r.path);
  // S3: a member's pane cannot reach the dashboard's data dir — the context
  // files and the prompt are copied into the member's handoff dir instead.
  const member = require("./run-as").accountForLane(laneId);
  let ctx = contextDir(laneId);
  if (member && files.length) {
    // Written AS the member (`write-as`): the dashboard never writes in a home.
    const runAs = require("./run-as");
    const sub = `context-${Number(laneId)}`;
    ctx = path.join(runAs.handoffDir(member), sub);
    runAs.removeAs(member, ctx);
    runAs.mkdirAs(member, ctx);
    files = files.map((f) =>
      runAs.handoffWrite(member, path.join(sub, path.basename(f)), fs.readFileSync(f))
    );
  }
  const addDirs = [...folders, ...(files.length ? [ctx] : [])];
  const parts = [];
  const mine = ownerInstructions(lane.owner_id);
  if (mine) parts.push(mine);
  if (lane.instructions) parts.push(lane.instructions);
  if (files.length) {
    parts.push(
      "Reference files for this workspace — read them when they are relevant:\n" +
        files.map((f) => `- ${f}`).join("\n")
    );
  }
  if (folders.length) {
    parts.push("Additional folders you may use:\n" + folders.map((f) => `- ${f}`).join("\n"));
  }
  if (!parts.length) return { addDirs, systemPrompt: null, systemPromptFile: null };
  const systemPrompt = parts.join("\n\n");
  // Written at every spawn, so the pane reads what the rows say now.
  // A data dir that cannot be written costs the pane its instructions (all of
  // Claude's, Codex's past the inline budget), never its start — same as a
  // vanished source.
  // The file is a `CLAUDE.md` alone in a folder of its own: Claude reads it as
  // memory from that folder (`--add-dir` + CLAUDE_CODE_ADDITIONAL_DIRECTORIES_
  // CLAUDE_MD, pty-run.js), not as `--append-system-prompt-file` — a custom
  // system prompt is a launch flag Claude cannot carry over a restart, so it
  // refused `/tui` (switching renderer restarts the session) in every pane
  // that had instructions. Codex names the same file in its pointer line.
  try {
    const sub = `prompt-${Number(laneId)}`;
    if (member) {
      const runAs = require("./run-as");
      runAs.mkdirAs(member, path.join(runAs.handoffDir(member), sub));
      const file = runAs.handoffWrite(member, path.join(sub, "CLAUDE.md"), systemPrompt);
      return { addDirs, systemPrompt, systemPromptFile: file };
    }
    const dir = path.join(getDataDir(), "workspace-prompts", String(Number(laneId)));
    fs.mkdirSync(dir, { recursive: true, mode: 0o700 });
    const systemPromptFile = path.join(dir, "CLAUDE.md");
    fs.writeFileSync(systemPromptFile, systemPrompt, { mode: 0o600 });
    return { addDirs, systemPrompt, systemPromptFile };
  } catch (err) {
    console.warn(`[lane-sources] workspace ${laneId}: prompt file not written:`, err.message);
    return { addDirs, systemPrompt, systemPromptFile: null };
  }
}

/** `text` as a TOML basic string: JSON's escapes are TOML's, except that TOML
 *  also refuses a raw DEL, which JSON.stringify leaves as is. */
function tomlString(text) {
  return JSON.stringify(text).replace(/\x7f/g, "\\u007f");
}

/** The developer instructions Codex gets inline: the text itself while it is
 *  small, else one line pointing at the file (see INLINE_PROMPT_BYTES), or
 *  null when it is too long and no file was written. */
function codexInstructions(systemPrompt, systemPromptFile) {
  // Measured as sent: escaping can double the text (quotes, newlines) or more.
  if (Buffer.byteLength(tomlString(systemPrompt)) <= INLINE_PROMPT_BYTES) return systemPrompt;
  if (!systemPromptFile) return null;
  return `This workspace's instructions and reference files are in ${systemPromptFile} — read that file before anything else and follow it.`;
}

function readMemoryFile(label, file) {
  try {
    if (!fs.statSync(file).isFile()) return null; // no blocking open on a FIFO
    // S3: a file in a member's folder is read only when the OPEN file is a
    // regular file that member owns — a link they planted to /etc/shadow or
    // another member's login is never read with the dashboard's rights.
    const fd = require("./run-as").openSafe(file);
    try {
      const st = fs.fstatSync(fd);
      if (!st.isFile()) return null;
      const truncated = st.size > MAX_MEMORY_BYTES;
      const buf = Buffer.alloc(Math.min(st.size, MAX_MEMORY_BYTES));
      fs.readSync(fd, buf, 0, buf.length, 0);
      return {
        label,
        path: file,
        size: st.size,
        mtime: st.mtime.toISOString(),
        truncated,
        content: buf.toString("utf8"),
      };
    } finally {
      fs.closeSync(fd);
    }
  } catch {
    return null;
  }
}

/**
 * The memory a workspace's agent already reads, read-only: the folder's
 * CLAUDE.md / AGENTS.md family, and (Claude) its auto-memory directory
 * `<CLAUDE_HOME>/projects/<encoded cwd>/memory/`. Every path is derived from
 * the lane row; nothing is written.
 */
function memoryFiles(laneId) {
  const lane = laneRow(laneId);
  const out = [];
  const add = (label, file) => {
    const f = readMemoryFile(label, file);
    if (f) out.push(f);
  };
  add("CLAUDE.md", path.join(lane.cwd, "CLAUDE.md"));
  add(".claude/CLAUDE.md", path.join(lane.cwd, ".claude", "CLAUDE.md"));
  add("CLAUDE.local.md", path.join(lane.cwd, "CLAUDE.local.md"));
  add("AGENTS.md", path.join(lane.cwd, "AGENTS.md"));
  if ((lane.tool || "claude") === "claude") {
    const dir = path.join(getClaudeHome(), "projects", encodeCwd(lane.cwd), "memory");
    let names = [];
    try {
      names = fs
        .readdirSync(dir)
        .filter((n) => n.endsWith(".md"))
        .sort();
    } catch {
      /* no auto memory yet */
    }
    for (const n of names.slice(0, 50)) add(`memory/${n}`, path.join(dir, n));
  }
  return out;
}

module.exports = {
  SUPPORTED_TOOLS,
  MAX_FILE_BYTES,
  MAX_INSTRUCTIONS,
  supports,
  contextDir,
  listSources,
  addFolder,
  sourceFolder,
  addFile,
  removeSource,
  removeLaneContext,
  setInstructions,
  launchExtras,
  setUserInstructions,
  getUserInstructions,
  codexInstructions,
  tomlString,
  INLINE_PROMPT_BYTES,
  memoryFiles,
  safeName,
};