import { isAbsolute, relative, resolve } from "path";
import type { RunOptions } from "./shell";

/**
 * Shared context handed to every tool module. Tool modules must never reach
 * around this object to touch the filesystem or spawn processes -- containment,
 * size limits and the capability toggles all live here.
 */
export interface Workspace {
  /** Absolute, resolved workspace root. Nothing outside it may be touched. */
  readonly root: string;
  /** Byte ceiling for file reads, search scans and command output buffers. */
  readonly maxBytes: number;
  readonly maxFileSizeKb: number;
  readonly commandTimeoutSec: number;
  /** Ready-made options for `runCommand` from ./shell. */
  readonly runOptions: RunOptions;

  readonly allowWrite: boolean;
  readonly allowShell: boolean;
  readonly allowNetwork: boolean;
  readonly allowGitWrite: boolean;

  /**
   * Resolves a model-supplied path against the root, throwing if it escapes.
   * Every path a tool receives MUST go through this.
   */
  resolveInRoot(candidate: string): string;
  /** Root-relative display path, for messages back to the model. */
  rel(absolutePath: string): string;
}

export interface WorkspaceInit {
  root: string;
  maxFileSizeKb: number;
  commandTimeoutSec: number;
  allowWrite: boolean;
  allowShell: boolean;
  allowNetwork: boolean;
  allowGitWrite: boolean;
}

export function createWorkspace(init: WorkspaceInit): Workspace {
  const root = resolve(init.root);
  const maxBytes = init.maxFileSizeKb * 1024;
  return {
    root,
    maxBytes,
    maxFileSizeKb: init.maxFileSizeKb,
    commandTimeoutSec: init.commandTimeoutSec,
    runOptions: {
      cwd: root,
      timeoutMs: init.commandTimeoutSec * 1000,
      maxBuffer: maxBytes,
    },
    allowWrite: init.allowWrite,
    allowShell: init.allowShell,
    allowNetwork: init.allowNetwork,
    allowGitWrite: init.allowGitWrite,
    resolveInRoot(candidate: string): string {
      return resolveInRoot(root, candidate);
    },
    rel(absolutePath: string): string {
      const value = relative(root, absolutePath);
      return value === "" ? "." : value;
    },
  };
}

/**
 * Single choke point for path containment. Resolves `candidate` against `root`
 * and refuses anything that lands outside it.
 */
export function resolveInRoot(root: string, candidate: string): string {
  const target = isAbsolute(candidate) ? resolve(candidate) : resolve(root, candidate);
  const rel = relative(root, target);
  if (rel === "") return target;
  if (rel.startsWith("..") || isAbsolute(rel)) {
    throw new Error(
      `Path "${candidate}" is outside the workspace root. Only paths under ${root} are allowed.`,
    );
  }
  return target;
}

/** Directories never worth walking into. */
export const IGNORED_DIRS = new Set([
  "node_modules",
  ".git",
  ".svn",
  ".hg",
  "dist",
  "build",
  "out",
  "target",
  "__pycache__",
  ".venv",
  "venv",
  ".next",
  ".nuxt",
  ".cache",
  ".lmstudio-backups",
]);

/**
 * Models do not reliably use our parameter names -- they reach for the ones they
 * have seen elsewhere (`file_path`, `old_string`). Rejecting those costs the
 * model a whole turn for no reason, so every hot tool accepts the common aliases
 * and funnels them through here: first non-empty wins.
 */
export function firstText(...values: Array<string | undefined | null>): string {
  for (const value of values) {
    if (typeof value === "string" && value.trim() !== "") return value;
  }
  return "";
}

/**
 * A reasoning model's message text arrives as its chain-of-thought, an internal
 * separator, then the actual answer. Callers want the answer, so everything up
 * to the last separator is dropped.
 */
export function stripReasoning(text: string): string {
  const separator = /__LM_STUDIO_INTERNAL_LSEP[A-Za-z0-9_]*__/g;
  const matches = [...text.matchAll(separator)];
  if (matches.length === 0) return text.trim();
  const last = matches[matches.length - 1];
  const answer = text.slice((last.index ?? 0) + last[0].length).trim();
  // If the model put everything before the separator, keep that rather than
  // returning nothing.
  return answer === "" ? text.slice(0, last.index ?? 0).trim() : answer;
}

export function formatBytes(bytes: number): string {
  if (bytes < 1024) return `${bytes} B`;
  if (bytes < 1024 * 1024) return `${(bytes / 1024).toFixed(1)} KB`;
  return `${(bytes / (1024 * 1024)).toFixed(1)} MB`;
}

/** Truncates tool output so a small model's context is never blown out. */
export function clamp(text: string, maxChars: number, what = "output"): string {
  if (text.length <= maxChars) return text;
  return `${text.slice(0, maxChars)}\n\n[truncated: ${what} was ${text.length} chars, limit ${maxChars}]`;
}

import { isAbsolute, relative, resolve } from "path";
import type { RunOptions } from "./shell";

/**
 * Shared context handed to every tool module. Tool modules must never reach
 * around this object to touch the filesystem or spawn processes -- containment,
 * size limits and the capability toggles all live here.
 */
export interface Workspace {
  /** Absolute, resolved workspace root. Nothing outside it may be touched. */
  readonly root: string;
  /** Byte ceiling for file reads, search scans and command output buffers. */
  readonly maxBytes: number;
  readonly maxFileSizeKb: number;
  readonly commandTimeoutSec: number;
  /** Ready-made options for `runCommand` from ./shell. */
  readonly runOptions: RunOptions;

  readonly allowWrite: boolean;
  readonly allowShell: boolean;
  readonly allowNetwork: boolean;
  readonly allowGitWrite: boolean;

  /**
   * Resolves a model-supplied path against the root, throwing if it escapes.
   * Every path a tool receives MUST go through this.
   */
  resolveInRoot(candidate: string): string;
  /** Root-relative display path, for messages back to the model. */
  rel(absolutePath: string): string;
}

export interface WorkspaceInit {
  root: string;
  maxFileSizeKb: number;
  commandTimeoutSec: number;
  allowWrite: boolean;
  allowShell: boolean;
  allowNetwork: boolean;
  allowGitWrite: boolean;
}

export function createWorkspace(init: WorkspaceInit): Workspace {
  const root = resolve(init.root);
  const maxBytes = init.maxFileSizeKb * 1024;
  return {
    root,
    maxBytes,
    maxFileSizeKb: init.maxFileSizeKb,
    commandTimeoutSec: init.commandTimeoutSec,
    runOptions: {
      cwd: root,
      timeoutMs: init.commandTimeoutSec * 1000,
      maxBuffer: maxBytes,
    },
    allowWrite: init.allowWrite,
    allowShell: init.allowShell,
    allowNetwork: init.allowNetwork,
    allowGitWrite: init.allowGitWrite,
    resolveInRoot(candidate: string): string {
      return resolveInRoot(root, candidate);
    },
    rel(absolutePath: string): string {
      const value = relative(root, absolutePath);
      return value === "" ? "." : value;
    },
  };
}

/**
 * Single choke point for path containment. Resolves `candidate` against `root`
 * and refuses anything that lands outside it.
 */
export function resolveInRoot(root: string, candidate: string): string {
  const target = isAbsolute(candidate) ? resolve(candidate) : resolve(root, candidate);
  const rel = relative(root, target);
  if (rel === "") return target;
  if (rel.startsWith("..") || isAbsolute(rel)) {
    throw new Error(
      `Path "${candidate}" is outside the workspace root. Only paths under ${root} are allowed.`,
    );
  }
  return target;
}

/** Directories never worth walking into. */
export const IGNORED_DIRS = new Set([
  "node_modules",
  ".git",
  ".svn",
  ".hg",
  "dist",
  "build",
  "out",
  "target",
  "__pycache__",
  ".venv",
  "venv",
  ".next",
  ".nuxt",
  ".cache",
  ".lmstudio-backups",
]);

/**
 * Models do not reliably use our parameter names -- they reach for the ones they
 * have seen elsewhere (`file_path`, `old_string`). Rejecting those costs the
 * model a whole turn for no reason, so every hot tool accepts the common aliases
 * and funnels them through here: first non-empty wins.
 */
export function firstText(...values: Array<string | undefined | null>): string {
  for (const value of values) {
    if (typeof value === "string" && value.trim() !== "") return value;
  }
  return "";
}

/**
 * A reasoning model's message text arrives as its chain-of-thought, an internal
 * separator, then the actual answer. Callers want the answer, so everything up
 * to the last separator is dropped.
 */
export function stripReasoning(text: string): string {
  const separator = /__LM_STUDIO_INTERNAL_LSEP[A-Za-z0-9_]*__/g;
  const matches = [...text.matchAll(separator)];
  if (matches.length === 0) return text.trim();
  const last = matches[matches.length - 1];
  const answer = text.slice((last.index ?? 0) + last[0].length).trim();
  // If the model put everything before the separator, keep that rather than
  // returning nothing.
  return answer === "" ? text.slice(0, last.index ?? 0).trim() : answer;
}

export function formatBytes(bytes: number): string {
  if (bytes < 1024) return `${bytes} B`;
  if (bytes < 1024 * 1024) return `${(bytes / 1024).toFixed(1)} KB`;
  return `${(bytes / (1024 * 1024)).toFixed(1)} MB`;
}

/** Truncates tool output so a small model's context is never blown out. */
export function clamp(text: string, maxChars: number, what = "output"): string {
  if (text.length <= maxChars) return text;
  return `${text.slice(0, maxChars)}\n\n[truncated: ${what} was ${text.length} chars, limit ${maxChars}]`;
}