/**
 * Configuration system for claw-web.
 * EXACT parity with original claw-code Rust config.rs:
 * - File-based persistence (.claw.json, .claw/settings.json, .claw/settings.local.json)
 * - Config discovery from user home + project cwd
 * - Deep merge with source priority (User < Project < Local)
 * - MCP server configs (stdio, sse, http, ws)
 * - Hooks config (PreToolUse, PostToolUse)
 * - Plugin config (enabled, directories, install root)
 * - Permission mode config
 * - Model config
 */

import * as fs from "fs";
import * as path from "path";

// ─── Config Source (matches original ConfigSource enum) ─────────────────
export enum ConfigSource {
  User = "user",
  Project = "project",
  Local = "local",
}

// ─── Permission Modes (matches original ResolvedPermissionMode) ─────────
export enum ResolvedPermissionMode {
  ReadOnly = "read_only",
  WorkspaceWrite = "workspace_write",
  DangerFullAccess = "full_access",
}

// ─── Config Entry (matches original ConfigEntry) ────────────────────────
export interface ConfigEntry {
  source: ConfigSource;
  path: string;
}

// ─── MCP Transport Types (matches original McpTransport) ────────────────
export enum McpTransport {
  Stdio = "stdio",
  Sse = "sse",
  Http = "http",
  Ws = "ws",
  Sdk = "sdk",
  ManagedProxy = "managed_proxy",
}

// ─── MCP Server Configs (matches original McpServerConfig variants) ─────
export interface McpStdioServerConfig {
  transport: McpTransport.Stdio;
  command: string;
  args: string[];
  env: Record<string, string>;
}

export interface McpRemoteServerConfig {
  transport: McpTransport.Sse | McpTransport.Http;
  url: string;
  headers: Record<string, string>;
  headersHelper?: string;
  oauth?: McpOAuthConfig;
}

export interface McpWebSocketServerConfig {
  transport: McpTransport.Ws;
  url: string;
  headers: Record<string, string>;
  headersHelper?: string;
}

export interface McpSdkServerConfig {
  transport: McpTransport.Sdk;
  name: string;
}

export interface McpManagedProxyServerConfig {
  transport: McpTransport.ManagedProxy;
  url: string;
  id: string;
}

export interface McpOAuthConfig {
  clientId?: string;
  callbackPort?: number;
  authServerMetadataUrl?: string;
  xaa?: boolean;
}

export type McpServerConfig =
  | McpStdioServerConfig
  | McpRemoteServerConfig
  | McpWebSocketServerConfig
  | McpSdkServerConfig
  | McpManagedProxyServerConfig;

export interface ScopedMcpServerConfig {
  scope: ConfigSource;
  config: McpServerConfig;
}

// ─── Hooks Config (matches original RuntimeHookConfig) ──────────────────
export interface RuntimeHookConfig {
  preToolUse: string[];
  postToolUse: string[];
}

// ─── Plugin Config (matches original RuntimePluginConfig) ───────────────
export interface RuntimePluginConfig {
  enabledPlugins: Record<string, boolean>;
  externalDirectories: string[];
  installRoot?: string;
  registryPath?: string;
  bundledRoot?: string;
}

// ─── OAuth Config (matches original OAuthConfig) ────────────────────────
export interface OAuthConfig {
  clientId: string;
  authorizeUrl: string;
  tokenUrl: string;
  callbackPort?: number;
  manualRedirectUrl?: string;
  scopes: string[];
}

// ─── Sandbox Config (matches original SandboxConfig) ────────────────────
export interface SandboxConfig {
  isolationMode?: "none" | "read_only" | "full";
}

// ─── Feature Config (matches original RuntimeFeatureConfig) ─────────────
export interface RuntimeFeatureConfig {
  hooks: RuntimeHookConfig;
  plugins: RuntimePluginConfig;
  mcp: { servers: Record<string, ScopedMcpServerConfig> };
  oauth?: OAuthConfig;
  model?: string;
  permissionMode?: ResolvedPermissionMode;
  sandbox: SandboxConfig;
}

// ─── Runtime Config (matches original RuntimeConfig) ────────────────────
export interface RuntimeConfig {
  merged: Record<string, any>;
  loadedEntries: ConfigEntry[];
  featureConfig: RuntimeFeatureConfig;
}

// ─── RuntimeConfig accessor helpers (match original Rust impl) ──────────

export function configHooks(config: RuntimeConfig): RuntimeHookConfig {
  return config.featureConfig.hooks;
}

export function configPlugins(config: RuntimeConfig): RuntimePluginConfig {
  return config.featureConfig.plugins;
}

export function configMcp(config: RuntimeConfig): { servers: Record<string, ScopedMcpServerConfig> } {
  return config.featureConfig.mcp;
}

export function configOAuth(config: RuntimeConfig): OAuthConfig | undefined {
  return config.featureConfig.oauth;
}

export function configModel(config: RuntimeConfig): string | undefined {
  return config.featureConfig.model;
}

export function configPermissionMode(config: RuntimeConfig): ResolvedPermissionMode | undefined {
  return config.featureConfig.permissionMode;
}

export function configSandbox(config: RuntimeConfig): SandboxConfig {
  return config.featureConfig.sandbox;
}

/**
 * Merge hooks config using extend_unique — matches original RuntimeHookConfig::merged()
 */
export function mergeHooksConfig(base: RuntimeHookConfig, other: RuntimeHookConfig): RuntimeHookConfig {
  const merged = { preToolUse: [...base.preToolUse], postToolUse: [...base.postToolUse] };
  extendUnique(merged.preToolUse, other.preToolUse);
  extendUnique(merged.postToolUse, other.postToolUse);
  return merged;
}

export function configWithHooks(config: RuntimeConfig, hooks: RuntimeHookConfig): RuntimeConfig {
  return {
    ...config,
    featureConfig: { ...config.featureConfig, hooks },
  };
}

export function configWithPlugins(config: RuntimeConfig, plugins: RuntimePluginConfig): RuntimeConfig {
  return {
    ...config,
    featureConfig: { ...config.featureConfig, plugins },
  };
}

export function configGet(config: RuntimeConfig, key: string): any {
  return config.merged[key];
}

export function configAsJson(config: RuntimeConfig): Record<string, any> {
  return { ...config.merged };
}

export function configEmpty(): RuntimeConfig {
  return {
    merged: {},
    loadedEntries: [],
    featureConfig: {
      hooks: { preToolUse: [], postToolUse: [] },
      plugins: { enabledPlugins: {}, externalDirectories: [] },
      mcp: { servers: {} },
      model: undefined,
      permissionMode: undefined,
      sandbox: {},
    },
  };
}

// ─── Default config home (matches original default_config_home) ─────────
function defaultConfigHome(): string {
  const xdgConfig = process.env.XDG_CONFIG_HOME;
  if (xdgConfig) return path.join(xdgConfig, "claw-code");
  const home = process.env.HOME || "/home/ubuntu";
  return path.join(home, ".config", "claw-code");
}

// ─── Config Loader (matches original ConfigLoader) ──────────────────────
export class ConfigLoader {
  private cwd: string;
  private configHome: string;

  constructor(cwd: string, configHome?: string) {
    this.cwd = cwd;
    this.configHome = configHome || defaultConfigHome();
  }

  static defaultFor(cwd: string): ConfigLoader {
    return new ConfigLoader(cwd, defaultConfigHome());
  }

  getConfigHome(): string {
    return this.configHome;
  }

  /**
   * Discover config file paths in priority order.
   * Matches original discover() method:
   *   1. ~/.claw.json (user legacy)
   *   2. ~/.config/claw-code/settings.json (user)
   *   3. <cwd>/.claw.json (project)
   *   4. <cwd>/.claw/settings.json (project)
   *   5. <cwd>/.claw/settings.local.json (local)
   */
  discover(): ConfigEntry[] {
    const userLegacyPath = path.join(
      path.dirname(this.configHome),
      "..",
      ".claw.json"
    );
    return [
      { source: ConfigSource.User, path: userLegacyPath },
      { source: ConfigSource.User, path: path.join(this.configHome, "settings.json") },
      { source: ConfigSource.Project, path: path.join(this.cwd, ".claw.json") },
      { source: ConfigSource.Project, path: path.join(this.cwd, ".claw", "settings.json") },
      { source: ConfigSource.Local, path: path.join(this.cwd, ".claw", "settings.local.json") },
    ];
  }

  /**
   * Load and merge all config files.
   * Matches original load() method.
   */
  load(): RuntimeConfig {
    const merged: Record<string, any> = {};
    const loadedEntries: ConfigEntry[] = [];
    const mcpServers: Record<string, ScopedMcpServerConfig> = {};

    for (const entry of this.discover()) {
      const value = readOptionalJsonObject(entry.path);
      if (value === null) continue;

      // Parse MCP servers
      if (value.mcpServers && typeof value.mcpServers === "object") {
        for (const [name, serverValue] of Object.entries(value.mcpServers)) {
          const parsed = parseMcpServerConfig(name, serverValue as any);
          if (parsed) {
            mcpServers[name] = { scope: entry.source, config: parsed };
          }
        }
      }

      // Deep merge
      deepMergeObjects(merged, value);
      loadedEntries.push(entry);
    }

    const featureConfig: RuntimeFeatureConfig = {
      hooks: parseOptionalHooksConfig(merged),
      plugins: parseOptionalPluginConfig(merged),
      mcp: { servers: mcpServers },
      oauth: parseOptionalOAuthConfig(merged),
      model: typeof merged.model === "string" ? merged.model : undefined,
      permissionMode: parseOptionalPermissionMode(merged),
      sandbox: parseOptionalSandboxConfig(merged),
    };

    return { merged, loadedEntries, featureConfig };
  }
}

// ─── ConfigError (matches original ConfigError enum) ─────────────────────────────

export enum ConfigErrorKind {
  FileNotFound = "file_not_found",
  ParseError = "parse_error",
  ValidationError = "validation_error",
  IoError = "io_error",
}

export class ConfigError extends Error {
  kind: ConfigErrorKind;
  filePath?: string;

  constructor(kind: ConfigErrorKind, message: string, filePath?: string) {
    super(message);
    this.kind = kind;
    this.filePath = filePath;
    this.name = "ConfigError";
  }

  static fileNotFound(filePath: string): ConfigError {
    return new ConfigError(ConfigErrorKind.FileNotFound, `Config file not found: ${filePath}`, filePath);
  }

  static parseError(filePath: string, reason: string): ConfigError {
    return new ConfigError(ConfigErrorKind.ParseError, `Failed to parse config ${filePath}: ${reason}`, filePath);
  }

  static validationError(message: string): ConfigError {
    return new ConfigError(ConfigErrorKind.ValidationError, message);
  }
}

// ─── RuntimeConfig accessor: loaded_entries() ──────────────────────────────

/**
 * Get the list of loaded config entries with their sources.
 * Matches original RuntimeConfig::loaded_entries().
 */
export function configLoadedEntries(config: RuntimeConfig): ConfigEntry[] {
  return [...config.loadedEntries];
}

/**
 * Full config serialization — matches original RuntimeConfig::as_json().
 * Returns the complete merged config with feature config overlay.
 */
export function configAsJsonFull(config: RuntimeConfig): Record<string, any> {
  return {
    ...config.merged,
    _feature: {
      hooks: config.featureConfig.hooks,
      plugins: config.featureConfig.plugins,
      mcp: {
        servers: Object.fromEntries(
          Object.entries(config.featureConfig.mcp.servers).map(([name, scoped]) => [
            name,
            { scope: scoped.scope, ...scoped.config },
          ])
        ),
      },
      model: config.featureConfig.model,
      permissionMode: config.featureConfig.permissionMode,
      sandbox: config.featureConfig.sandbox,
    },
    _loaded: config.loadedEntries.map(e => ({ source: e.source, path: e.path })),
  };
}

// ─── Singleton config instance ──────────────────────────────────────────────────────
let _cachedConfig: RuntimeConfig | null = null;
let _cachedCwd: string | null = null;

/**
 * Get or load the runtime config for the given working directory.
 * Caches the result until invalidated.
 */
export function getConfig(cwd: string): RuntimeConfig {
  if (_cachedConfig && _cachedCwd === cwd) return _cachedConfig;
  const loader = ConfigLoader.defaultFor(cwd);
  _cachedConfig = loader.load();
  _cachedCwd = cwd;
  return _cachedConfig;
}

/**
 * Invalidate the cached config (e.g., after /config set).
 */
export function invalidateConfigCache(): void {
  _cachedConfig = null;
  _cachedCwd = null;
}

/**
 * Write a config value to the project-level settings file.
 * Matches the /config set behavior.
 */
export function setConfigValue(cwd: string, key: string, value: any): void {
  const configPath = path.join(cwd, ".claw", "settings.json");
  const dir = path.dirname(configPath);
  if (!fs.existsSync(dir)) {
    fs.mkdirSync(dir, { recursive: true });
  }
  let existing: Record<string, any> = {};
  try {
    const raw = fs.readFileSync(configPath, "utf-8");
    existing = JSON.parse(raw);
  } catch {
    // File doesn't exist or invalid JSON
  }
  // Support dot-notation keys (e.g., "hooks.PreToolUse")
  const keys = key.split(".");
  let obj = existing;
  for (let i = 0; i < keys.length - 1; i++) {
    if (!obj[keys[i]] || typeof obj[keys[i]] !== "object") {
      obj[keys[i]] = {};
    }
    obj = obj[keys[i]];
  }
  obj[keys[keys.length - 1]] = value;

  fs.writeFileSync(configPath, JSON.stringify(existing, null, 2) + "\n", "utf-8");
  invalidateConfigCache();
}

/**
 * Get a config value by dot-notation key.
 */
export function getConfigValue(cwd: string, key: string): any {
  const config = getConfig(cwd);
  const keys = key.split(".");
  let obj: any = config.merged;
  for (const k of keys) {
    if (obj === undefined || obj === null) return undefined;
    obj = obj[k];
  }
  return obj;
}

// ─── Helper Functions ───────────────────────────────────────────────────

function readOptionalJsonObject(filePath: string): Record<string, any> | null {
  try {
    const contents = fs.readFileSync(filePath, "utf-8");
    if (!contents.trim()) return {};
    const parsed = JSON.parse(contents);
    if (typeof parsed !== "object" || Array.isArray(parsed)) {
      // Legacy .claw.json files might not be objects
      if (filePath.endsWith(".claw.json")) return null;
      return null;
    }
    return parsed;
  } catch {
    return null;
  }
}

function deepMergeObjects(target: Record<string, any>, source: Record<string, any>): void {
  for (const [key, value] of Object.entries(source)) {
    if (
      key !== "mcpServers" && // MCP servers handled separately
      value !== null &&
      typeof value === "object" &&
      !Array.isArray(value) &&
      target[key] &&
      typeof target[key] === "object" &&
      !Array.isArray(target[key])
    ) {
      deepMergeObjects(target[key], value);
    } else {
      target[key] = value;
    }
  }
}

function parseMcpServerConfig(name: string, value: any): McpServerConfig | null {
  if (!value || typeof value !== "object") return null;

  // Determine transport type
  if (value.command) {
    return {
      transport: McpTransport.Stdio,
      command: value.command,
      args: Array.isArray(value.args) ? value.args : [],
      env: value.env && typeof value.env === "object" ? value.env : {},
    };
  }
  if (value.url) {
    const transport = value.transport || "sse";
    if (transport === "ws" || transport === "websocket") {
      return {
        transport: McpTransport.Ws,
        url: value.url,
        headers: value.headers || {},
        headersHelper: value.headersHelper,
      };
    }
    if (transport === "managed_proxy") {
      return {
        transport: McpTransport.ManagedProxy,
        url: value.url,
        id: value.id || name,
      };
    }
    return {
      transport: transport === "http" ? McpTransport.Http : McpTransport.Sse,
      url: value.url,
      headers: value.headers || {},
      headersHelper: value.headersHelper,
      oauth: value.oauth
        ? {
            clientId: value.oauth.clientId,
            callbackPort: value.oauth.callbackPort,
            authServerMetadataUrl: value.oauth.authServerMetadataUrl,
            xaa: value.oauth.xaa,
          }
        : undefined,
    };
  }
  if (value.name) {
    return { transport: McpTransport.Sdk, name: value.name };
  }
  return null;
}

// ─── extend_unique / push_unique (matches original config.rs) ──────────────

function pushUnique(target: string[], value: string): void {
  if (!target.includes(value)) {
    target.push(value);
  }
}

function extendUnique(target: string[], values: string[]): void {
  for (const value of values) {
    pushUnique(target, value);
  }
}

function parseOptionalHooksConfig(merged: Record<string, any>): RuntimeHookConfig {
  const hooks = merged.hooks;
  if (!hooks || typeof hooks !== "object") {
    return { preToolUse: [], postToolUse: [] };
  }
  // Support all naming conventions: PascalCase (original), snake_case, camelCase
  const pre = hooks.PreToolUse || hooks.pre_tool_use || hooks.preToolUse || [];
  const post = hooks.PostToolUse || hooks.post_tool_use || hooks.postToolUse || [];
  return {
    preToolUse: Array.isArray(pre) ? pre.filter((s: any) => typeof s === "string") : [],
    postToolUse: Array.isArray(post) ? post.filter((s: any) => typeof s === "string") : [],
  };
}

function parseOptionalPluginConfig(merged: Record<string, any>): RuntimePluginConfig {
  const config: RuntimePluginConfig = {
    enabledPlugins: {},
    externalDirectories: [],
  };
  if (merged.enabledPlugins && typeof merged.enabledPlugins === "object") {
    for (const [k, v] of Object.entries(merged.enabledPlugins)) {
      if (typeof v === "boolean") config.enabledPlugins[k] = v;
    }
  }
  const plugins = merged.plugins;
  if (!plugins || typeof plugins !== "object") return config;
  if (plugins.enabled && typeof plugins.enabled === "object") {
    for (const [k, v] of Object.entries(plugins.enabled)) {
      if (typeof v === "boolean") config.enabledPlugins[k] = v;
    }
  }
  if (Array.isArray(plugins.externalDirectories)) {
    config.externalDirectories = plugins.externalDirectories.filter((s: any) => typeof s === "string");
  }
  if (typeof plugins.installRoot === "string") config.installRoot = plugins.installRoot;
  if (typeof plugins.registryPath === "string") config.registryPath = plugins.registryPath;
  if (typeof plugins.bundledRoot === "string") config.bundledRoot = plugins.bundledRoot;
  return config;
}

function parseOptionalOAuthConfig(merged: Record<string, any>): OAuthConfig | undefined {
  const oauth = merged.oauth;
  if (!oauth || typeof oauth !== "object") return undefined;
  if (!oauth.clientId || !oauth.authorizeUrl || !oauth.tokenUrl) return undefined;
  return {
    clientId: oauth.clientId,
    authorizeUrl: oauth.authorizeUrl,
    tokenUrl: oauth.tokenUrl,
    callbackPort: oauth.callbackPort,
    manualRedirectUrl: oauth.manualRedirectUrl,
    scopes: Array.isArray(oauth.scopes) ? oauth.scopes : [],
  };
}

function parseOptionalPermissionMode(merged: Record<string, any>): ResolvedPermissionMode | undefined {
  const mode = merged.permissions?.mode || merged.permissionMode;
  if (!mode || typeof mode !== "string") return undefined;
  const normalized = mode.toLowerCase().replace(/[-_\s]/g, "");
  if (normalized === "readonly" || normalized === "readOnly") return ResolvedPermissionMode.ReadOnly;
  if (normalized === "workspacewrite" || normalized === "workspace") return ResolvedPermissionMode.WorkspaceWrite;
  if (normalized === "fullaccess" || normalized === "danger" || normalized === "dangerfullaccess") return ResolvedPermissionMode.DangerFullAccess;
  return undefined;
}

function parseOptionalSandboxConfig(merged: Record<string, any>): SandboxConfig {
  const sandbox = merged.sandbox;
  if (!sandbox || typeof sandbox !== "object") return {};
  return {
    isolationMode: sandbox.isolationMode,
  };
}