/**
 * OpenChamber project-level configuration service.
 * Stores per-project settings in ~/.config/openchamber/<projectId>.json.
 * Migrates from legacy <project>/.openchamber/openchamber.json.
 */

import type { FilesAPI, RuntimeAPIs } from './api/types';
import { getDesktopHomeDirectory } from './desktop';
import { isVSCodeRuntime } from './desktop';

type ProjectRef = { id: string; path: string };

const CONFIG_FILENAME = 'openchamber.json';
// LEGACY_PROJECT_CONFIG: legacy per-project config root inside repo.
const LEGACY_CONFIG_DIR = '.openchamber';
const USER_CONFIG_DIR_SEGMENTS = ['.config', 'openchamber'];
const USER_PROJECTS_DIR_SEGMENTS = ['.config', 'openchamber', 'projects'];
const SETTINGS_FILENAME = 'settings.json';

const projectIdCache = new Map<string, string>();

const isSafeConfigFileId = (value: string): boolean => /^[A-Za-z0-9._-]+$/.test(value);

const toHex = (bytes: Uint8Array): string => {
  let out = '';
  for (const b of bytes) {
    out += b.toString(16).padStart(2, '0');
  }
  return out;
};

const sha1Hex = async (value: string): Promise<string | null> => {
  try {
    if (typeof crypto === 'undefined' || !crypto.subtle) {
      return null;
    }
    const encoder = new TextEncoder();
    const data = encoder.encode(value);
    const digest = await crypto.subtle.digest('SHA-1', data);
    return toHex(new Uint8Array(digest));
  } catch {
    return null;
  }
};

/**
 * Get the runtime Files API if available (Desktop/VSCode).
 */
function getRuntimeFilesAPI(): FilesAPI | null {
  if (typeof window === 'undefined') return null;
  const apis = (window as typeof window & { __OPENCHAMBER_RUNTIME_APIS__?: RuntimeAPIs }).__OPENCHAMBER_RUNTIME_APIS__;
  if (apis?.files) {
    return apis.files;
  }
  return null;
}

export interface OpenChamberConfig {
  'setup-worktree'?: string[];
}

const normalize = (value: string): string => {
  if (!value) return '';
  const replaced = value.replace(/\\/g, '/');
  return replaced === '/' ? '/' : replaced.replace(/\/+$/, '');
};

const joinPath = (base: string, segment: string): string => {
  const normalizedBase = normalize(base);
  const cleanSegment = segment.replace(/\\/g, '/').replace(/^\/+/, '').replace(/\/+$/, '');
  if (!normalizedBase || normalizedBase === '/') {
    return `/${cleanSegment}`;
  }
  return `${normalizedBase}/${cleanSegment}`;
};

const getLegacyConfigPath = (projectDirectory: string): string => {
  return joinPath(joinPath(projectDirectory, LEGACY_CONFIG_DIR), CONFIG_FILENAME);
};

const getBaseUrl = (): string => {
  const defaultBaseUrl = import.meta.env.VITE_OPENCODE_URL || '/api';
  if (defaultBaseUrl.startsWith('/')) {
    return defaultBaseUrl;
  }
  return defaultBaseUrl;
};

const postJson = async <T>(url: string, body: unknown): Promise<{ ok: boolean; data: T | null }> => {
  try {
    const response = await fetch(url, {
      method: 'POST',
      headers: { 'Content-Type': 'application/json' },
      body: JSON.stringify(body),
    });
    if (!response.ok) {
      return { ok: false, data: null };
    }
    const data = (await response.json().catch(() => null)) as T | null;
    return { ok: true, data };
  } catch {
    return { ok: false, data: null };
  }
};

const mkdirp = async (path: string): Promise<boolean> => {
  const runtimeFiles = getRuntimeFilesAPI();
  if (runtimeFiles?.createDirectory) {
    try {
      const result = await runtimeFiles.createDirectory(path);
      if (result?.success) {
        return true;
      }
    } catch {
      // fall through
    }
  }

  const res = await postJson<{ success?: boolean }>(`${getBaseUrl()}/fs/mkdir`, { path });
  return Boolean(res.ok);
};

const readTextFile = async (path: string): Promise<string | null> => {
  const runtimeFiles = getRuntimeFilesAPI();
  if (runtimeFiles?.readFile) {
    try {
      const result = await runtimeFiles.readFile(path);
      const content = typeof result?.content === 'string' ? result.content : '';
      return content;
    } catch {
      return null;
    }
  }

  try {
    const response = await fetch(`${getBaseUrl()}/fs/read?path=${encodeURIComponent(path)}`);
    if (!response.ok) {
      return null;
    }
    return await response.text();
  } catch {
    return null;
  }
};

const writeTextFile = async (path: string, content: string): Promise<boolean> => {
  const runtimeFiles = getRuntimeFilesAPI();
  if (runtimeFiles?.writeFile) {
    try {
      const result = await runtimeFiles.writeFile(path, content);
      if (result?.success) {
        return true;
      }
    } catch {
      // fall through
    }
  }

  const res = await postJson<{ success?: boolean }>(`${getBaseUrl()}/fs/write`, { path, content });
  return Boolean(res.ok);
};

const resolveHomeDirectory = async (): Promise<string | null> => {
  // VSCode webview sets __OPENCHAMBER_HOME__ to workspace folder (not OS home).
  // For user config (~/.config/openchamber), always use /api/fs/home in VSCode.
  if (!isVSCodeRuntime()) {
    const desktopHome = await getDesktopHomeDirectory().catch(() => null);
    if (desktopHome && desktopHome.trim().length > 0) {
      return normalize(desktopHome);
    }
  }

  try {
    const response = await fetch(`${getBaseUrl()}/fs/home`);
    if (!response.ok) {
      return null;
    }
    const payload = await response.json().catch(() => null) as { home?: unknown } | null;
    const home = typeof payload?.home === 'string' ? payload.home.trim() : '';
    return home ? normalize(home) : null;
  } catch {
    return null;
  }
};

const getUserConfigRootDirectory = async (): Promise<string | null> => {
  const home = await resolveHomeDirectory();
  if (!home) {
    return null;
  }
  return USER_CONFIG_DIR_SEGMENTS.reduce((acc, segment) => joinPath(acc, segment), home);
};

const getUserProjectsDirectory = async (): Promise<string | null> => {
  const home = await resolveHomeDirectory();
  if (!home) {
    return null;
  }
  return USER_PROJECTS_DIR_SEGMENTS.reduce((acc, segment) => joinPath(acc, segment), home);
};

const getSettingsPath = async (): Promise<string | null> => {
  const base = await getUserConfigRootDirectory();
  if (!base) {
    return null;
  }
  return joinPath(base, SETTINGS_FILENAME);
};

const resolveConfigProjectId = async (project: ProjectRef): Promise<string | null> => {
  const projectDirectory = typeof project?.path === 'string' ? project.path.trim() : '';
  const normalizedProject = projectDirectory ? normalize(projectDirectory) : '';

  const explicitId = typeof project?.id === 'string' ? project.id.trim() : '';
  if (explicitId && isSafeConfigFileId(explicitId)) {
    return explicitId;
  }

  if (normalizedProject) {
    const cached = projectIdCache.get(normalizedProject);
    if (cached) {
      return cached;
    }
  }

  // Best-effort map project directory -> persisted project id from settings.json.
  const settingsPath = await getSettingsPath();
  if (settingsPath && normalizedProject) {
    const raw = await readTextFile(settingsPath);
    if (raw) {
      try {
        const parsed = JSON.parse(raw) as { projects?: unknown };
        const projects = Array.isArray(parsed?.projects) ? parsed.projects : [];
        for (const entry of projects) {
          if (!entry || typeof entry !== 'object') continue;
          const record = entry as { id?: unknown; path?: unknown };
          const id = typeof record.id === 'string' ? record.id.trim() : '';
          const path = typeof record.path === 'string' ? normalize(record.path.trim()) : '';
          if (id && isSafeConfigFileId(id) && path && path === normalizedProject) {
            projectIdCache.set(normalizedProject, id);
            return id;
          }
        }
      } catch {
        // ignore
      }
    }
  }

  // Fallback: stable id derived from path (used in VSCode when project isn't registered).
  if (normalizedProject) {
    const digest = await sha1Hex(normalizedProject);
    const fallback = digest ? `path_${digest}` : `path_${normalizedProject.replace(/[^A-Za-z0-9._-]+/g, '_')}`;
    projectIdCache.set(normalizedProject, fallback);
    return fallback;
  }

  return null;
};

const getUserConfigPath = async (project: ProjectRef): Promise<string | null> => {
  const base = await getUserProjectsDirectory();
  if (!base) {
    return null;
  }
  const safeId = await resolveConfigProjectId(project);
  if (!safeId) {
    return null;
  }
  return joinPath(base, `${safeId}.json`);
};

/**
 * Read the config for a project.
 * Returns null if file doesn't exist or is invalid.
 */
export async function readOpenChamberConfig(project: ProjectRef): Promise<OpenChamberConfig | null> {
  const projectDirectory = typeof project?.path === 'string' ? project.path.trim() : '';
  if (!projectDirectory) {
    return null;
  }

  const configPath = await getUserConfigPath(project);

  const readText = async (path: string): Promise<string | null> => {
    // Keep behavior consistent with other helpers.
    const text = await readTextFile(path);
    if (text === null) {
      return null;
    }
    return text;
  };

  const parseConfig = (text: string | null): OpenChamberConfig | null => {
    if (typeof text !== 'string') {
      return null;
    }
    const trimmed = text.trim();
    if (!trimmed) {
      return null;
    }
    try {
      const parsed = JSON.parse(trimmed);
      if (!parsed || typeof parsed !== 'object') {
        return null;
      }
      return parsed as OpenChamberConfig;
    } catch {
      return null;
    }
  };

  // 1) Prefer new per-user config.
  if (configPath) {
    const existing = parseConfig(await readText(configPath));
    if (existing) {
      return existing;
    }
  }

  // 2) Migrate legacy <project>/.openchamber/openchamber.json.
  // LEGACY_PROJECT_CONFIG: migrate project-local openchamber.json -> ~/.config/openchamber/projects/<projectId>.json
  const legacyPath = getLegacyConfigPath(projectDirectory);
  const legacyConfig = parseConfig(await readText(legacyPath));
  if (!legacyConfig) {
    return null;
  }

  // Best-effort write + delete legacy.
  try {
    const wrote = await writeOpenChamberConfig(project, legacyConfig);
    if (wrote) {
      await deleteLegacyOpenChamberConfig(projectDirectory);
    }
  } catch {
    // Ignore migration failures; still return legacy content.
  }

  return legacyConfig;
}

/**
 * Write the per-user config for a project.
 */
export async function writeOpenChamberConfig(
  project: ProjectRef,
  config: OpenChamberConfig
): Promise<boolean> {
  const projectDirectory = typeof project?.path === 'string' ? project.path.trim() : '';
  if (!projectDirectory) {
    return false;
  }

  const configDir = await getUserProjectsDirectory();
  const configPath = await getUserConfigPath(project);
  if (!configDir || !configPath) {
    return false;
  }

  try {
    // Ensure user config directory exists.
    const okDir = await mkdirp(configDir);
    if (!okDir) {
      return false;
    }

    const content = JSON.stringify(config, null, 2);
    return await writeTextFile(configPath, content);
  } catch (error) {
    console.error('Failed to write openchamber config:', error);
    return false;
  }
}

/**
 * Update specific keys in the config, preserving other values.
 */
export async function updateOpenChamberConfig(
  project: ProjectRef,
  updates: Partial<OpenChamberConfig>
): Promise<boolean> {
  const existing = await readOpenChamberConfig(project) || {};
  const merged = { ...existing, ...updates };
  return writeOpenChamberConfig(project, merged);
}

/**
 * Get worktree setup commands from config.
 */
export async function getWorktreeSetupCommands(project: ProjectRef): Promise<string[]> {
  const config = await readOpenChamberConfig(project);
  return config?.['setup-worktree'] ?? [];
}

export async function saveWorktreeSetupCommands(project: ProjectRef, commands: string[]): Promise<boolean> {
  const filtered = commands.filter((cmd) => cmd.trim().length > 0);
  return updateOpenChamberConfig(project, { 'setup-worktree': filtered });
}

/**
 * Substitute variables in a command string.
 * Supported variables:
 * - $ROOT_PROJECT_PATH: The root project directory path
 * - $ROOT_WORKTREE_PATH: Legacy alias for $ROOT_PROJECT_PATH
 */
export function substituteCommandVariables(
  command: string,
  variables: { rootWorktreePath: string }
): string {
  return command
    // New preferred name
    .replace(/\$ROOT_PROJECT_PATH/g, variables.rootWorktreePath)
    .replace(/\$\{ROOT_PROJECT_PATH\}/g, variables.rootWorktreePath)
    // Legacy
    .replace(/\$ROOT_WORKTREE_PATH/g, variables.rootWorktreePath)
    .replace(/\$\{ROOT_WORKTREE_PATH\}/g, variables.rootWorktreePath);
}

async function deleteLegacyOpenChamberConfig(projectDirectory: string): Promise<void> {
  const legacyPath = getLegacyConfigPath(projectDirectory);
  const runtimeFiles = getRuntimeFilesAPI();

  if (runtimeFiles?.delete) {
    try {
      await runtimeFiles.delete(legacyPath);
      return;
    } catch {
      // fall through
    }
  }

  try {
    await postJson(`${getBaseUrl()}/fs/delete`, { path: legacyPath });
  } catch {
    // ignored
  }
}

export type { ProjectRef };