import Database from 'better-sqlite3';
import { randomUUID } from 'node:crypto';
import type { StorageAdapter, StorageConfig } from '../types.js';

/* eslint-disable @typescript-eslint/no-explicit-any */

const COLLECTIONS = [
  'users',
  'sessions',
  'accounts',
  'projects',
  'missions',
  'tasks',
  'agents',
  'conversations',
  'messages',
  'preferences',
  'insights',
  'skills',
  'events',
  'routing_rules',
  'provider_credentials',
  'agent_logs',
  'teams',
  'team_members',
  'mission_tasks',
  'tickets',
  'summarization_jobs',
  'appreciations',
  'verifications',
] as const;

function buildFilterClause(filter?: Record<string, unknown>): {
  clause: string;
  params: unknown[];
} {
  if (!filter || Object.keys(filter).length === 0) return { clause: '', params: [] };
  const conditions: string[] = [];
  const params: unknown[] = [];
  for (const [key, value] of Object.entries(filter)) {
    if (key === 'id') {
      conditions.push('id = ?');
      params.push(value);
    } else {
      conditions.push(`json_extract(data_json, '$.${key}') = ?`);
      params.push(typeof value === 'object' ? JSON.stringify(value) : value);
    }
  }
  return { clause: ` WHERE ${conditions.join(' AND ')}`, params };
}

export class SqliteAdapter implements StorageAdapter {
  readonly name = 'sqlite';
  private db: Database.Database;

  constructor(config: Extract<StorageConfig, { type: 'sqlite' }>) {
    this.db = new Database(config.path);
    this.db.pragma('journal_mode = WAL');
    this.db.pragma('foreign_keys = ON');
  }

  async create<T extends Record<string, unknown>>(
    collection: string,
    data: T,
  ): Promise<T & { id: string }> {
    const id = (data as any).id ?? randomUUID();
    const now = new Date().toISOString();
    const rest = Object.fromEntries(Object.entries(data).filter(([k]) => k !== 'id'));
    this.db
      .prepare(
        `INSERT INTO ${collection} (id, data_json, created_at, updated_at) VALUES (?, ?, ?, ?)`,
      )
      .run(id, JSON.stringify(rest), now, now);
    return { ...data, id } as T & { id: string };
  }

  async read<T extends Record<string, unknown>>(collection: string, id: string): Promise<T | null> {
    const row = this.db.prepare(`SELECT * FROM ${collection} WHERE id = ?`).get(id) as any;
    if (!row) return null;
    return { id: row.id, ...JSON.parse(row.data_json as string) } as T;
  }

  async update(collection: string, id: string, data: Record<string, unknown>): Promise<boolean> {
    const existing = this.db
      .prepare(`SELECT data_json FROM ${collection} WHERE id = ?`)
      .get(id) as any;
    if (!existing) return false;
    const merged = { ...JSON.parse(existing.data_json as string), ...data };
    const now = new Date().toISOString();
    const result = this.db
      .prepare(`UPDATE ${collection} SET data_json = ?, updated_at = ? WHERE id = ?`)
      .run(JSON.stringify(merged), now, id);
    return result.changes > 0;
  }

  async delete(collection: string, id: string): Promise<boolean> {
    const result = this.db.prepare(`DELETE FROM ${collection} WHERE id = ?`).run(id);
    return result.changes > 0;
  }

  async find<T extends Record<string, unknown>>(
    collection: string,
    filter?: Record<string, unknown>,
    opts?: { limit?: number; offset?: number; orderBy?: string; order?: 'asc' | 'desc' },
  ): Promise<T[]> {
    const { clause, params } = buildFilterClause(filter);
    let query = `SELECT * FROM ${collection}${clause}`;
    if (opts?.orderBy) {
      const dir = opts.order === 'desc' ? 'DESC' : 'ASC';
      const col =
        opts.orderBy === 'id' || opts.orderBy === 'created_at' || opts.orderBy === 'updated_at'
          ? opts.orderBy
          : `json_extract(data_json, '$.${opts.orderBy}')`;
      query += ` ORDER BY ${col} ${dir}`;
    }
    if (opts?.limit) {
      query += ` LIMIT ?`;
      params.push(opts.limit);
    }
    if (opts?.offset) {
      query += ` OFFSET ?`;
      params.push(opts.offset);
    }
    const rows = this.db.prepare(query).all(...params) as any[];
    return rows.map((row) => ({ id: row.id, ...JSON.parse(row.data_json as string) }) as T);
  }

  async findOne<T extends Record<string, unknown>>(
    collection: string,
    filter: Record<string, unknown>,
  ): Promise<T | null> {
    const results = await this.find<T>(collection, filter, { limit: 1 });
    return results[0] ?? null;
  }

  async count(collection: string, filter?: Record<string, unknown>): Promise<number> {
    const { clause, params } = buildFilterClause(filter);
    const row = this.db
      .prepare(`SELECT COUNT(*) as count FROM ${collection}${clause}`)
      .get(...params) as any;
    return row?.count ?? 0;
  }

  async transaction<T>(fn: (tx: StorageAdapter) => Promise<T>): Promise<T> {
    const txAdapter = new SqliteTxAdapter(this.db);
    this.db.exec('BEGIN');
    try {
      const result = await fn(txAdapter);
      this.db.exec('COMMIT');
      return result;
    } catch (err) {
      this.db.exec('ROLLBACK');
      throw err;
    }
  }

  async migrate(): Promise<void> {
    const createTable = (name: string) =>
      this.db.exec(`
        CREATE TABLE IF NOT EXISTS ${name} (
          id TEXT PRIMARY KEY,
          data_json TEXT NOT NULL DEFAULT '{}',
          created_at TEXT NOT NULL DEFAULT (datetime('now')),
          updated_at TEXT NOT NULL DEFAULT (datetime('now'))
        )
      `);
    for (const collection of COLLECTIONS) {
      createTable(collection);
    }
  }

  async close(): Promise<void> {
    this.db.close();
  }
}

/**
 * Transaction wrapper that uses the same db handle — better-sqlite3 transactions
 * are connection-level, so all statements on the same Database instance within
 * a db.transaction() callback participate in the transaction.
 */
class SqliteTxAdapter implements StorageAdapter {
  readonly name = 'sqlite';
  private db: Database.Database;

  constructor(db: Database.Database) {
    this.db = db;
  }

  async create<T extends Record<string, unknown>>(
    collection: string,
    data: T,
  ): Promise<T & { id: string }> {
    const id = (data as any).id ?? randomUUID();
    const now = new Date().toISOString();
    const rest = Object.fromEntries(Object.entries(data).filter(([k]) => k !== 'id'));
    this.db
      .prepare(
        `INSERT INTO ${collection} (id, data_json, created_at, updated_at) VALUES (?, ?, ?, ?)`,
      )
      .run(id, JSON.stringify(rest), now, now);
    return { ...data, id } as T & { id: string };
  }

  async read<T extends Record<string, unknown>>(collection: string, id: string): Promise<T | null> {
    const row = this.db.prepare(`SELECT * FROM ${collection} WHERE id = ?`).get(id) as any;
    if (!row) return null;
    return { id: row.id, ...JSON.parse(row.data_json as string) } as T;
  }

  async update(collection: string, id: string, data: Record<string, unknown>): Promise<boolean> {
    const existing = this.db
      .prepare(`SELECT data_json FROM ${collection} WHERE id = ?`)
      .get(id) as any;
    if (!existing) return false;
    const merged = { ...JSON.parse(existing.data_json as string), ...data };
    const now = new Date().toISOString();
    const result = this.db
      .prepare(`UPDATE ${collection} SET data_json = ?, updated_at = ? WHERE id = ?`)
      .run(JSON.stringify(merged), now, id);
    return result.changes > 0;
  }

  async delete(collection: string, id: string): Promise<boolean> {
    const result = this.db.prepare(`DELETE FROM ${collection} WHERE id = ?`).run(id);
    return result.changes > 0;
  }

  async find<T extends Record<string, unknown>>(
    collection: string,
    filter?: Record<string, unknown>,
    opts?: { limit?: number; offset?: number; orderBy?: string; order?: 'asc' | 'desc' },
  ): Promise<T[]> {
    const { clause, params } = buildFilterClause(filter);
    let query = `SELECT * FROM ${collection}${clause}`;
    if (opts?.orderBy) {
      const dir = opts.order === 'desc' ? 'DESC' : 'ASC';
      const col =
        opts.orderBy === 'id' || opts.orderBy === 'created_at' || opts.orderBy === 'updated_at'
          ? opts.orderBy
          : `json_extract(data_json, '$.${opts.orderBy}')`;
      query += ` ORDER BY ${col} ${dir}`;
    }
    if (opts?.limit) {
      query += ` LIMIT ?`;
      params.push(opts.limit);
    }
    if (opts?.offset) {
      query += ` OFFSET ?`;
      params.push(opts.offset);
    }
    const rows = this.db.prepare(query).all(...params) as any[];
    return rows.map((row) => ({ id: row.id, ...JSON.parse(row.data_json as string) }) as T);
  }

  async findOne<T extends Record<string, unknown>>(
    collection: string,
    filter: Record<string, unknown>,
  ): Promise<T | null> {
    const results = await this.find<T>(collection, filter, { limit: 1 });
    return results[0] ?? null;
  }

  async count(collection: string, filter?: Record<string, unknown>): Promise<number> {
    const { clause, params } = buildFilterClause(filter);
    const row = this.db
      .prepare(`SELECT COUNT(*) as count FROM ${collection}${clause}`)
      .get(...params) as any;
    return row?.count ?? 0;
  }

  async transaction<T>(fn: (tx: StorageAdapter) => Promise<T>): Promise<T> {
    return fn(this);
  }

  async migrate(): Promise<void> {
    // No-op inside transaction
  }

  async close(): Promise<void> {
    // No-op inside transaction
  }
}