import {
  exists,
  mkdir,
  readTextFile,
  writeTextFile,
  readDir,
  remove,
  copyFile,
} from "@tauri-apps/plugin-fs";
import { appDataDir, join } from "@tauri-apps/api/path";
import { boardSchema, appSettingsSchema } from "./schemas";
import type { Board, BoardMeta } from "@/types/board";
import type { AppSettings } from "@/types/settings";

// ---------------------------------------------------------------------------
// Path helpers
// ---------------------------------------------------------------------------

async function getBaseDir(): Promise<string> {
  const base = await appDataDir();
  return join(base, "openpylon");
}

async function getBoardsDir(): Promise<string> {
  const base = await getBaseDir();
  return join(base, "boards");
}

async function getAttachmentsDir(): Promise<string> {
  const base = await getBaseDir();
  return join(base, "attachments");
}

async function getSettingsPath(): Promise<string> {
  const base = await getBaseDir();
  return join(base, "settings.json");
}

function boardFilePath(boardsDir: string, boardId: string): Promise<string> {
  return join(boardsDir, `${boardId}.json`);
}

function boardBackupPath(boardsDir: string, boardId: string): Promise<string> {
  return join(boardsDir, `${boardId}.backup.json`);
}

// ---------------------------------------------------------------------------
// Directory setup
// ---------------------------------------------------------------------------

export async function ensureDataDirs(): Promise<void> {
  const base = await getBaseDir();
  if (!(await exists(base))) {
    await mkdir(base, { recursive: true });
  }

  const boardsDir = await getBoardsDir();
  if (!(await exists(boardsDir))) {
    await mkdir(boardsDir, { recursive: true });
  }

  const attachmentsDir = await getAttachmentsDir();
  if (!(await exists(attachmentsDir))) {
    await mkdir(attachmentsDir, { recursive: true });
  }
}

// ---------------------------------------------------------------------------
// Settings
// ---------------------------------------------------------------------------

export async function loadSettings(): Promise<AppSettings> {
  const settingsPath = await getSettingsPath();

  if (!(await exists(settingsPath))) {
    const defaults = appSettingsSchema.parse({});
    return defaults;
  }

  try {
    const raw = await readTextFile(settingsPath);
    const data = JSON.parse(raw);
    return appSettingsSchema.parse(data);
  } catch {
    // If the file is corrupted, return defaults
    return appSettingsSchema.parse({});
  }
}

export async function saveSettings(settings: AppSettings): Promise<void> {
  const settingsPath = await getSettingsPath();
  await writeTextFile(settingsPath, JSON.stringify(settings, null, 2));
}

// ---------------------------------------------------------------------------
// Board listing
// ---------------------------------------------------------------------------

export async function listBoards(): Promise<BoardMeta[]> {
  const boardsDir = await getBoardsDir();

  if (!(await exists(boardsDir))) {
    return [];
  }

  const entries = await readDir(boardsDir);
  const metas: BoardMeta[] = [];

  for (const entry of entries) {
    // DirEntry has `name` property in Tauri v2
    if (!entry.name || !entry.name.endsWith(".json") || entry.name.endsWith(".backup.json")) {
      continue;
    }

    try {
      const filePath = await join(boardsDir, entry.name);
      const raw = await readTextFile(filePath);
      const data = JSON.parse(raw);
      const board = boardSchema.parse(data);

      metas.push({
        id: board.id,
        title: board.title,
        color: board.color,
        cardCount: Object.keys(board.cards).length,
        columnCount: board.columns.length,
        updatedAt: board.updatedAt,
      });
    } catch {
      // Skip corrupted board files
      continue;
    }
  }

  // Sort by updatedAt descending (most recent first)
  metas.sort((a, b) => b.updatedAt.localeCompare(a.updatedAt));
  return metas;
}

// ---------------------------------------------------------------------------
// Board CRUD
// ---------------------------------------------------------------------------

export async function loadBoard(boardId: string): Promise<Board> {
  const boardsDir = await getBoardsDir();
  const filePath = await boardFilePath(boardsDir, boardId);

  const raw = await readTextFile(filePath);
  const data = JSON.parse(raw);
  return boardSchema.parse(data) as Board;
}

export async function saveBoard(board: Board): Promise<void> {
  const boardsDir = await getBoardsDir();
  const filePath = await boardFilePath(boardsDir, board.id);
  const backupPath = await boardBackupPath(boardsDir, board.id);

  // Rotate previous version to backup
  if (await exists(filePath)) {
    try {
      const previous = await readTextFile(filePath);
      await writeTextFile(backupPath, previous);
    } catch {
      // If we can't create a backup, continue saving anyway
    }
  }

  await writeTextFile(filePath, JSON.stringify(board, null, 2));
}

export async function deleteBoard(boardId: string): Promise<void> {
  const boardsDir = await getBoardsDir();
  const filePath = await boardFilePath(boardsDir, boardId);
  const backupPath = await boardBackupPath(boardsDir, boardId);

  // Remove board file
  if (await exists(filePath)) {
    await remove(filePath);
  }

  // Remove backup file
  if (await exists(backupPath)) {
    await remove(backupPath);
  }

  // Remove board attachments directory
  const attachmentsDir = await getAttachmentsDir();
  const boardAttachmentsDir = await join(attachmentsDir, boardId);
  if (await exists(boardAttachmentsDir)) {
    await remove(boardAttachmentsDir, { recursive: true });
  }
}

// ---------------------------------------------------------------------------
// Backup restoration
// ---------------------------------------------------------------------------

export async function restoreFromBackup(boardId: string): Promise<Board> {
  const boardsDir = await getBoardsDir();
  const backupPath = await boardBackupPath(boardsDir, boardId);

  const raw = await readTextFile(backupPath);
  const data = JSON.parse(raw);
  const board = boardSchema.parse(data) as Board;

  // Save the restored board as the current version
  await saveBoard(board);

  return board;
}

// ---------------------------------------------------------------------------
// Search
// ---------------------------------------------------------------------------

export interface SearchResult {
  boardId: string;
  boardTitle: string;
  cardId: string;
  cardTitle: string;
  matchField: "title" | "description";
}

export async function searchAllBoards(query: string): Promise<SearchResult[]> {
  const boardsDir = await getBoardsDir();

  if (!(await exists(boardsDir))) {
    return [];
  }

  const entries = await readDir(boardsDir);
  const results: SearchResult[] = [];
  const lowerQuery = query.toLowerCase();

  for (const entry of entries) {
    if (!entry.name || !entry.name.endsWith(".json") || entry.name.endsWith(".backup.json")) {
      continue;
    }

    try {
      const filePath = await join(boardsDir, entry.name);
      const raw = await readTextFile(filePath);
      const data = JSON.parse(raw);
      const board = boardSchema.parse(data);

      for (const card of Object.values(board.cards)) {
        if (card.title.toLowerCase().includes(lowerQuery)) {
          results.push({
            boardId: board.id,
            boardTitle: board.title,
            cardId: card.id,
            cardTitle: card.title,
            matchField: "title",
          });
        } else if (card.description.toLowerCase().includes(lowerQuery)) {
          results.push({
            boardId: board.id,
            boardTitle: board.title,
            cardId: card.id,
            cardTitle: card.title,
            matchField: "description",
          });
        }
      }
    } catch {
      continue;
    }
  }

  return results;
}

// ---------------------------------------------------------------------------
// Attachment helpers
// ---------------------------------------------------------------------------

export async function copyAttachment(
  boardId: string,
  sourcePath: string,
  fileName: string,
): Promise<string> {
  const attachmentsDir = await getAttachmentsDir();
  const boardAttDir = await join(attachmentsDir, boardId);

  if (!(await exists(boardAttDir))) {
    await mkdir(boardAttDir, { recursive: true });
  }

  const destPath = await join(boardAttDir, fileName);
  await copyFile(sourcePath, destPath);
  return destPath;
}