/**
 * Static Redis command metadata, distilled from the official Redis command table
 * (redis-doc `commands.json` / the `COMMAND` output). Kept offline and lightweight:
 * we only retain what the editor syntax diagnostics need — `arity` and `group` —
 * plus a `safety` hint for danger/write-command highlighting.
 *
 * Arity semantics (matches the Redis `COMMAND` reply, command name INCLUDED in the count):
 *   arity > 0  → the command takes exactly `arity` tokens (e.g. GET key → arity 2).
 *   arity < 0  → the command takes AT LEAST `-arity` tokens (e.g. MSET k v [k v ...] → arity -3).
 *
 * `safety` is aligned with the token-level sets in `redisCommandSafety.ts` (used to gate
 * execution). Here it is recorded per-command (including subcommands) so diagnostics can
 * be more precise than the first-token classification.
 *
 * Subcommands are keyed as `"MAIN SUB"` in UPPER CASE (e.g. `"CONFIG GET"`, `"XGROUP CREATE"`).
 */
import type { RedisCommandSafety } from "@/lib/redisCommandSafety";

export interface RedisCommandSpec {
  /** Token count including the command name. Positive = exact, negative = minimum (-N). */
  arity: number;
  /** Redis command group: string/list/hash/.../server. */
  group: string;
  /** Danger level for diagnostic highlighting. */
  safety: RedisCommandSafety;
}

type Spec = [arity: number, group: string, safety?: RedisCommandSafety];

// Compact tuple form → expanded into the record below.
const RAW_COMMANDS: Record<string, Spec> = {
  // ---- String ----
  APPEND: [3, "string", "confirm"],
  DECR: [2, "string", "confirm"],
  DECRBY: [3, "string", "confirm"],
  GET: [2, "string"],
  GETDEL: [2, "string", "confirm"],
  GETEX: [-2, "string"],
  GETRANGE: [4, "string"],
  GETSET: [3, "string", "confirm"],
  INCR: [2, "string", "confirm"],
  INCRBY: [3, "string", "confirm"],
  INCRBYFLOAT: [3, "string", "confirm"],
  LCS: [-3, "string"],
  MGET: [-2, "string"],
  MSET: [-3, "string", "confirm"],
  MSETNX: [-3, "string", "confirm"],
  PSETEX: [4, "string", "confirm"],
  SET: [-3, "string", "confirm"],
  SETEX: [4, "string", "confirm"],
  SETNX: [3, "string", "confirm"],
  SETRANGE: [4, "string", "confirm"],
  STRLEN: [2, "string"],

  // ---- Generic key ----
  COPY: [-3, "generic", "confirm"],
  DEL: [-2, "generic", "confirm"],
  DUMP: [2, "generic"],
  EXISTS: [-2, "generic"],
  EXPIRE: [-3, "generic", "confirm"],
  EXPIREAT: [-3, "generic", "confirm"],
  KEYS: [2, "generic", "blocked"],
  MIGRATE: [-6, "generic", "blocked"],
  MOVE: [3, "generic", "confirm"],
  OBJECT_ENCODING: [3, "generic"],
  OBJECT_FREQ: [3, "generic"],
  OBJECT_IDLETIME: [3, "generic"],
  OBJECT_REFCOUNT: [3, "generic"],
  OBJECT_HELP: [2, "generic"],
  PERSIST: [2, "generic", "confirm"],
  PEXPIRE: [-3, "generic", "confirm"],
  PEXPIREAT: [-3, "generic", "confirm"],
  PTTL: [2, "generic"],
  RANDOMKEY: [1, "generic"],
  RENAME: [3, "generic", "confirm"],
  RENAMENX: [3, "generic", "confirm"],
  RESTORE: [-4, "generic", "confirm"],
  SCAN: [-2, "generic"],
  SORT: [-2, "generic", "confirm"],
  SORT_RO: [-2, "generic"],
  TOUCH: [-2, "generic"],
  TTL: [2, "generic"],
  TYPE: [2, "generic"],
  UNLINK: [-2, "generic", "confirm"],
  WAIT: [3, "generic"],
  WAITAOF: [4, "generic"],

  // ---- List ----
  BLMOVE: [6, "list"],
  BLMPOP: [-4, "list"],
  BLPOP: [-3, "list"],
  BRPOP: [-3, "list"],
  BRPOPLPUSH: [4, "list"],
  LINDEX: [3, "list"],
  LINSERT: [5, "list", "confirm"],
  LLEN: [2, "list"],
  LMOVE: [5, "list", "confirm"],
  LMPOP: [-4, "list", "confirm"],
  LPOP: [-2, "list", "confirm"],
  LPOS: [-2, "list"],
  LPUSH: [-3, "list", "confirm"],
  LPUSHX: [-3, "list", "confirm"],
  LRANGE: [4, "list"],
  LREM: [4, "list", "confirm"],
  LSET: [4, "list", "confirm"],
  LTRIM: [4, "list", "confirm"],
  RPOP: [-2, "list", "confirm"],
  RPOPLPUSH: [4, "list", "confirm"],
  RPUSH: [-3, "list", "confirm"],
  RPUSHX: [-3, "list", "confirm"],

  // ---- Hash ----
  HDEL: [-3, "hash", "confirm"],
  HEXISTS: [3, "hash"],
  HGET: [3, "hash"],
  HGETALL: [2, "hash"],
  HINCRBY: [4, "hash", "confirm"],
  HINCRBYFLOAT: [4, "hash", "confirm"],
  HKEYS: [2, "hash"],
  HLEN: [2, "hash"],
  HMGET: [-3, "hash"],
  HMSET: [-4, "hash", "confirm"],
  HRANDFIELD: [-2, "hash"],
  HSCAN: [-3, "hash"],
  HSET: [-4, "hash", "confirm"],
  HSETNX: [4, "hash", "confirm"],
  HSTRLEN: [3, "hash"],
  HVALS: [2, "hash"],

  // ---- Set ----
  SADD: [-3, "set", "confirm"],
  SCARD: [2, "set"],
  SDIFF: [-2, "set"],
  SDIFFSTORE: [-3, "set", "confirm"],
  SINTER: [-2, "set"],
  SINTERCARD: [-3, "set"],
  SINTERSTORE: [-3, "set", "confirm"],
  SISMEMBER: [3, "set"],
  SMEMBERS: [2, "set"],
  SMISMEMBER: [-3, "set"],
  SMOVE: [4, "set", "confirm"],
  SPOP: [-2, "set", "confirm"],
  SRANDMEMBER: [-2, "set"],
  SREM: [-3, "set", "confirm"],
  SSCAN: [-3, "set"],
  SUNION: [-2, "set"],
  SUNIONSTORE: [-3, "set", "confirm"],

  // ---- Sorted set ----
  BZMPOP: [-3, "zset"],
  BZPOPMAX: [-3, "zset"],
  BZPOPMIN: [-3, "zset"],
  ZADD: [-4, "zset", "confirm"],
  ZCARD: [2, "zset"],
  ZCOUNT: [4, "zset"],
  ZDIFF: [-3, "zset"],
  ZDIFFSTORE: [-4, "zset", "confirm"],
  ZINCRBY: [4, "zset", "confirm"],
  ZINTER: [-3, "zset"],
  ZINTERCARD: [-3, "zset"],
  ZINTERSTORE: [-4, "zset", "confirm"],
  ZLEXCOUNT: [4, "zset"],
  ZMPOP: [-3, "zset", "confirm"],
  ZMSCORE: [-3, "zset"],
  ZPOPMAX: [-2, "zset", "confirm"],
  ZPOPMIN: [-2, "zset", "confirm"],
  ZRANGE: [-4, "zset"],
  ZRANGEBYLEX: [-4, "zset"],
  ZRANGEBYSCORE: [-4, "zset"],
  ZRANGESTORE: [-5, "zset", "confirm"],
  ZRANK: [-3, "zset"],
  ZREM: [-3, "zset", "confirm"],
  ZREMRANGEBYLEX: [4, "zset", "confirm"],
  ZREMRANGEBYRANK: [4, "zset", "confirm"],
  ZREMRANGEBYSCORE: [4, "zset", "confirm"],
  ZREVRANGE: [-4, "zset"],
  ZREVRANGEBYLEX: [-4, "zset"],
  ZREVRANGEBYSCORE: [-4, "zset"],
  ZREVRANK: [-3, "zset"],
  ZSCAN: [-3, "zset"],
  ZSCORE: [3, "zset"],
  ZUNION: [-3, "zset"],
  ZUNIONSTORE: [-4, "zset", "confirm"],

  // ---- Bitmap ----
  BITCOUNT: [-2, "bitmap"],
  BITFIELD: [-2, "bitmap", "confirm"],
  BITFIELD_RO: [-2, "bitmap"],
  BITOP: [-4, "bitmap", "confirm"],
  BITPOS: [-3, "bitmap"],
  GETBIT: [3, "bitmap"],
  SETBIT: [4, "bitmap", "confirm"],

  // ---- Hyperloglog ----
  PFADD: [-2, "hyperloglog", "confirm"],
  PFCOUNT: [-2, "hyperloglog"],
  PFMERGE: [-2, "hyperloglog", "confirm"],

  // ---- Geo ----
  GEOADD: [-5, "geo", "confirm"],
  GEODIST: [-4, "geo"],
  GEOHASH: [-3, "geo"],
  GEOPOS: [-3, "geo"],
  GEORADIUS: [-6, "geo", "confirm"],
  GEORADIUS_RO: [-6, "geo"],
  GEORADIUSBYMEMBER: [-5, "geo", "confirm"],
  GEORADIUSBYMEMBER_RO: [-5, "geo"],
  GEOSEARCH: [-7, "geo"],
  GEOSEARCHSTORE: [-8, "geo", "confirm"],

  // ---- Stream ----
  XACK: [-4, "stream", "confirm"],
  XADD: [-5, "stream", "confirm"],
  XAUTOCLAIM: [-7, "stream", "confirm"],
  XCLAIM: [-6, "stream", "confirm"],
  XDEL: [-3, "stream", "confirm"],
  "XGROUP CREATE": [-6, "stream", "confirm"],
  "XGROUP CREATECONSUMER": [5, "stream", "confirm"],
  "XGROUP DELCONSUMER": [4, "stream", "confirm"],
  "XGROUP DESTROY": [4, "stream", "confirm"],
  "XGROUP HELP": [2, "stream"],
  "XGROUP SETID": [-5, "stream", "confirm"],
  "XINFO CONSUMERS": [4, "stream"],
  "XINFO GROUPS": [3, "stream"],
  "XINFO HELP": [2, "stream"],
  "XINFO STREAM": [-3, "stream"],
  XLEN: [2, "stream"],
  XPENDING: [-3, "stream"],
  XRANGE: [-4, "stream"],
  XREAD: [-4, "stream"],
  XREADGROUP: [-7, "stream"],
  XREVRANGE: [-4, "stream"],
  XSETID: [-3, "stream", "confirm"],
  XTRIM: [-4, "stream", "confirm"],

  // ---- Pub/Sub ----
  PSUBSCRIBE: [-2, "pubsub"],
  PUBLISH: [3, "pubsub"],
  "PUBSUB CHANNELS": [-2, "pubsub"],
  "PUBSUB NUMPAT": [1, "pubsub"],
  "PUBSUB NUMSUB": [-2, "pubsub"],
  "PUBSUB SHARDCHANNELS": [-2, "pubsub"],
  "PUBSUB SHARDNUMSUB": [-2, "pubsub"],
  PUNSUBSCRIBE: [-1, "pubsub"],
  SPUBLISH: [3, "pubsub"],
  SSUBSCRIBE: [2, "pubsub"],
  SUBSCRIBE: [-2, "pubsub"],
  SUNSUBSCRIBE: [-1, "pubsub"],
  UNSUBSCRIBE: [-1, "pubsub"],

  // ---- Transactions ----
  DISCARD: [1, "transactions"],
  EXEC: [1, "transactions"],
  MULTI: [1, "transactions"],
  UNWATCH: [1, "transactions"],
  WATCH: [-2, "transactions"],

  // ---- Scripting ----
  EVAL: [-3, "scripting", "blocked"],
  EVALSHA: [-3, "scripting", "blocked"],
  EVAL_RO: [-3, "scripting", "blocked"],
  EVALSHA_RO: [-3, "scripting", "blocked"],
  FCALL: [-3, "scripting"],
  FCALL_RO: [-3, "scripting"],
  "FUNCTION DELETE": [3, "scripting", "confirm"],
  "FUNCTION DUMP": [2, "scripting"],
  "FUNCTION FLUSH": [-2, "scripting", "confirm"],
  "FUNCTION LIST": [-2, "scripting"],
  "FUNCTION LOAD": [-3, "scripting", "confirm"],
  "FUNCTION RESTORE": [-4, "scripting", "confirm"],
  "FUNCTION STATS": [1, "scripting"],
  "SCRIPT EXISTS": [-2, "scripting", "blocked"],
  "SCRIPT FLUSH": [-2, "scripting", "blocked"],
  "SCRIPT KILL": [1, "scripting", "blocked"],
  "SCRIPT LOAD": [2, "scripting", "blocked"],

  // ---- Connection ----
  AUTH: [-2, "connection"],
  ECHO: [2, "connection"],
  HELLO: [-1, "connection"],
  PING: [-1, "connection"],
  QUIT: [1, "connection"],
  RESET: [1, "connection"],
  SELECT: [2, "connection"],
  "CLIENT CACHING": [3, "connection"],
  "CLIENT GETNAME": [1, "connection"],
  "CLIENT GETREDIR": [1, "connection"],
  "CLIENT ID": [1, "connection"],
  "CLIENT INFO": [1, "connection"],
  "CLIENT KILL": [-3, "connection", "confirm"],
  "CLIENT LIST": [-2, "connection"],
  "CLIENT NO-EVICT": [2, "connection"],
  "CLIENT NO-TOUCH": [2, "connection"],
  "CLIENT PAUSE": [-2, "connection"],
  "CLIENT REPLY": [2, "connection"],
  "CLIENT SETINFO": [-3, "connection"],
  "CLIENT SETNAME": [3, "connection"],
  "CLIENT TRACKING": [-3, "connection"],
  "CLIENT TRACKINGINFO": [1, "connection"],
  "CLIENT UNPAUSE": [1, "connection"],

  // ---- Server ----
  BGREWRITEAOF: [1, "server"],
  BGSAVE: [-1, "server", "blocked"],
  "COMMAND COUNT": [1, "server"],
  "COMMAND DOCS": [-2, "server"],
  "COMMAND GETKEYS": [-3, "server"],
  "COMMAND INFO": [-2, "server"],
  "COMMAND LIST": [-2, "server"],
  "CONFIG GET": [-2, "server", "blocked"],
  "CONFIG RESETSTAT": [1, "server", "blocked"],
  "CONFIG REWRITE": [1, "server", "blocked"],
  "CONFIG SET": [-3, "server", "blocked"],
  DBSIZE: [1, "server"],
  FAILOVER: [-1, "server", "confirm"],
  FLUSHALL: [-1, "server", "blocked"],
  FLUSHDB: [-1, "server", "confirm"],
  INFO: [-1, "server"],
  LASTSAVE: [1, "server"],
  "MEMORY USAGE": [-3, "server"],
  "MEMORY STATS": [1, "server"],
  "MEMORY PURGE": [1, "server"],
  "MEMORY DOCS": [1, "server"],
  "MODULE LIST": [1, "server", "blocked"],
  "MODULE LOAD": [-3, "server", "blocked"],
  "MODULE LOADEX": [-3, "server", "blocked"],
  "MODULE UNLOAD": [3, "server", "blocked"],
  MONITOR: [1, "server"],
  REPLICAOF: [3, "server", "blocked"],
  ROLE: [1, "server"],
  SAVE: [1, "server", "blocked"],
  SHUTDOWN: [-1, "server", "blocked"],
  SLAVEOF: [3, "server", "blocked"],
  "SLOWLOG GET": [-2, "server"],
  "SLOWLOG LEN": [1, "server"],
  "SLOWLOG RESET": [1, "server"],
  "SLOWLOG HELP": [1, "server"],
  SWAPDB: [3, "server", "confirm"],
  SYNC: [1, "server"],
  TIME: [1, "server"],

  // ---- Cluster ----
  "CLUSTER ADDSLOTS": [-3, "cluster", "confirm"],
  "CLUSTER COUNT-FAILURE-REPORTS": [2, "cluster"],
  "CLUSTER COUNTKEYSINSLOT": [3, "cluster"],
  "CLUSTER DELSLOTS": [-3, "cluster", "confirm"],
  "CLUSTER FAILOVER": [-2, "cluster", "confirm"],
  "CLUSTER FLUSHSLOTS": [1, "cluster", "confirm"],
  "CLUSTER FORGET": [2, "cluster", "confirm"],
  "CLUSTER GETKEYSINSLOT": [4, "cluster"],
  "CLUSTER INFO": [1, "cluster"],
  "CLUSTER KEYSLOT": [2, "cluster"],
  "CLUSTER LINKS": [1, "cluster"],
  "CLUSTER MEET": [-4, "cluster", "confirm"],
  "CLUSTER MYID": [1, "cluster"],
  "CLUSTER NODES": [1, "cluster"],
  "CLUSTER REPLICAS": [2, "cluster"],
  "CLUSTER REPLICATE": [2, "cluster", "confirm"],
  "CLUSTER RESET": [-2, "cluster", "confirm"],
  "CLUSTER SAVECONFIG": [1, "cluster", "confirm"],
  "CLUSTER SET-CONFIG-EPOCH": [2, "cluster", "confirm"],
  "CLUSTER SETSLOT": [-4, "cluster", "confirm"],
  "CLUSTER SHARDS": [1, "cluster"],
  "CLUSTER SLAVES": [2, "cluster"],
  "CLUSTER SLOTS": [1, "cluster"],
  READONLY: [1, "cluster"],
  READWRITE: [1, "cluster"],
};

export const REDIS_COMMAND_TABLE: Record<string, RedisCommandSpec> = Object.fromEntries(Object.entries(RAW_COMMANDS).map(([name, [arity, group, safety]]) => [name.toUpperCase(), { arity, group, safety: safety ?? "allowed" }]));

/**
 * Resolve a command spec. Handles two-token subcommands (e.g. `XGROUP CREATE`,
 * `CONFIG GET`) by trying `MAIN SUB` first, then falling back to the main token.
 */
export function resolveRedisCommandSpec(argvUpper: readonly string[]): RedisCommandSpec | undefined {
  if (argvUpper.length === 0) return undefined;
  const main = argvUpper[0];
  if (argvUpper.length >= 2) {
    const sub = `${main} ${argvUpper[1]}`;
    const subSpec = REDIS_COMMAND_TABLE[sub];
    if (subSpec) return subSpec;
  }
  return REDIS_COMMAND_TABLE[main];
}

/**
 * Minimal argv tokenizer for the first two tokens of a Redis command line —
 * enough to resolve a spec (which only needs the command head, optionally a
 * subcommand). Single-quoted, double-quoted and unquoted tokens are supported
 * with backslash escapes; quoting errors are tolerated (the token still resolves).
 * Kept local so this module stays self-contained (no dependency on the syntax
 * diagnostics tokenizer).
 */
function firstRedisArgvUpper(line: string): string[] {
  const tokens: string[] = [];
  let i = 0;
  const n = line.length;
  while (i < n && tokens.length < 2) {
    while (i < n && /\s/.test(line[i])) i++;
    if (i >= n) break;
    const quote = line[i] === '"' || line[i] === "'" ? line[i] : "";
    let token = "";
    let escaping = false;
    if (quote) i++;
    while (i < n) {
      const ch = line[i];
      if (escaping) {
        token += ch;
        escaping = false;
        i++;
        continue;
      }
      if (ch === "\\") {
        escaping = true;
        i++;
        continue;
      }
      if (quote && ch === quote) {
        i++;
        break;
      }
      if (!quote && /\s/.test(ch)) break;
      token += ch;
      i++;
    }
    tokens.push(token.toUpperCase());
  }
  return tokens;
}

// Commands marked `safety: "blocked"` because they are dangerous/administrative,
// but which do NOT actually change the key set of the current db — so they should
// NOT trigger key-name completion cache invalidation. (e.g. KEYS is read-only;
// SAVE/BGSAVE/SHUTDOWN/REPLICAOF/SLAVEOF are server admin.) Everything else in the
// `blocked` set (FLUSHALL, MIGRATE, EVAL[ESHA]) may mutate keys and is left in.
const NON_MUTATING_BLOCKED = new Set(["KEYS", "BGSAVE", "SAVE", "SHUTDOWN", "REPLICAOF", "SLAVEOF"]);

/**
 * True when a command may change the key set of the db it ran on (adds/edits/
 * removes/renames keys, or wipes the db), and therefore the cached key-name
 * completion for that db is potentially stale and should be dropped.
 *
 * Mapping from the diagnostic `safety` field:
 *   - `confirm`  → every write command mutates keys (SET/DEL/INCR/HSET/...).
 *   - `blocked`  → mostly destructive/admin; we keep the ones that may touch keys
 *                  (FLUSHALL, MIGRATE, EVAL[ESHA]) and exclude the read-only/admin
 *                  ones in `NON_MUTATING_BLOCKED`.
 *   - `allowed`  → read-only (GET/LRANGE/SCAN/...), never invalidates.
 *
 * Commands absent from the table (unknown or read-only extensions) are treated as
 * non-mutating so we never thrash the cache on lookups.
 */
export function isRedisMutatingCommand(command: string): boolean {
  const argv = firstRedisArgvUpper(command);
  const spec = resolveRedisCommandSpec(argv);
  if (!spec) return false;
  if (spec.safety === "confirm") return true;
  if (spec.safety === "blocked") {
    return !NON_MUTATING_BLOCKED.has(argv[0]);
  }
  return false;
}