# SPDX-License-Identifier: Apache-2.0
# SPDX-FileCopyrightText: 2025 DBVisor

defmodule SQL.Parser do
  @moduledoc false
  @compile {:inline, parse: 1, parse: 5, predicate: 1, insert_node: 5}

  import Kernel, except: [is_boolean: 1]

  defguard is_and(node) when elem(node, 0) == :and
  defguard is_between(node) when elem(node, 0) == :between
  defguard is_boolean(node) when elem(node, 0) in ~w[and or <> <= >= != < > !< !> = true false unknown like ilike in all any is isnull notnull between]a
  defguard is_combinator(node) when elem(node, 0) in ~w[except intersect union]a and elem(node, 2) == []
  defguard is_comma(node) when elem(node, 0) == :comma
  defguard is_comment(node) when elem(node, 0) in ~w[comment comments]a
  defguard is_conditional(node) when elem(node, 0) in ~w[and or]a and elem(node, 2) == []
  defguard is_colon(node) when elem(node, 0) == :colon
  defguard is_distinct(node) when elem(node, 0) == :distinct
  defguard is_declare(node) when elem(node, 0) == :declare
  defguard is_data_type(node) when elem(node, 0) in ~w[integer float ident quote double_quote backtick bracket parens . binding]a
  defguard is_fetch(node) when elem(node, 0) == :fetch
  defguard is_fetch_dir(node) when elem(node, 0) in ~w[absolute backward forward relative]a
  defguard is_from(node) when elem(node, 0) == :from
  defguard is_for(node) when elem(node, 0) == :for
  defguard is_grant(node) when elem(node, 0) == :grant
  defguard is_revoke(node) when elem(node, 0) == :revoke
  defguard is_keyword(node) when elem(node, 0) in [:abs, :absent, :acos, :all, :allocate, :alter, :and, :any, :any_value, :are, :array, :array_agg, :array_max_cardinality, :as, :asensitive, :asin, :asymmetric, :at, :atan, :atomic, :authorization, :avg, :begin, :begin_frame, :begin_partition, :between, :bigint, :binary, :blob, :boolean, :both, :btrim, :by, :call, :called, :cardinality, :cascaded, :case, :cast, :ceil, :ceiling, :char, :char_length, :character, :character_length, :check, :classifier, :clob, :close, :coalesce, :collate, :collect, :column, :commit, :condition, :connect, :constraint, :contains, :convert, :copy, :corr, :corresponding, :cos, :cosh, :count, :covar_pop, :covar_samp, :create, :cross, :cube, :cume_dist, :current, :current_catalog, :current_date, :current_default_transform_group, :current_path, :current_role, :current_row, :current_schema, :current_time, :current_timestamp, :current_transform_group_for_type, :current_user, :cursor, :cycle, :date, :day, :deallocate, :dec, :decfloat, :decimal, :declare, :default, :define, :delete, :dense_rank, :deref, :describe, :deterministic, :disconnect, :distinct, :double, :drop, :dynamic, :each, :element, :else, :empty, :end, :end_frame, :end_partition, :"end-exec", :equals, :escape, :every, :except, :exec, :execute, :exists, :exp, :external, :extract, false, :fetch, :filter, :first_value, :float, :floor, :for, :foreign, :frame_row, :free, :from, :full, :function, :fusion, :get, :global, :grant, :greatest, :group, :grouping, :groups, :having, :hold, :hour, :identity, :in, :indicator, :initial, :inner, :inout, :insensitive, :insert, :int, :integer, :intersect, :intersection, :interval, :into, :is, :join, :json, :json_array, :json_arrayagg, :json_exists, :json_object, :json_objectagg, :json_query, :json_scalar, :json_serialize, :json_table, :json_table_primitive, :json_value, :lag, :language, :large, :last_value, :lateral, :lead, :leading, :least, :left, :like, :like_regex, :listagg, :ln, :local, :localtime, :localtimestamp, :log, :log10, :lower, :lpad, :ltrim, :match, :match_number, :match_recognize, :matches, :max, :member, :merge, :method, :min, :minute, :mod, :modifies, :module, :month, :multiset, :national, :natural, :nchar, :nclob, :new, :no, :none, :normalize, :not, :nth_value, :ntile, :null, :nullif, :numeric, :occurrences_regex, :octet_length, :of, :offset, :old, :omit, :on, :one, :only, :open, :or, :order, :out, :outer, :over, :overlaps, :overlay, :parameter, :partition, :pattern, :per, :percent, :percent_rank, :percentile_cont, :percentile_disc, :period, :portion, :position, :position_regex, :power, :precedes, :precision, :prepare, :primary, :procedure, :ptf, :range, :rank, :reads, :real, :recursive, :ref, :references, :referencing, :regr_avgx, :regr_avgy, :regr_count, :regr_intercept, :regr_r2, :regr_slope, :regr_sxx, :regr_sxy, :regr_syy, :release, :result, :return, :returns, :revoke, :right, :rollback, :rollup, :row, :row_number, :rows, :rpad, :rtrim, :running, :savepoint, :scope, :scroll, :search, :second, :seek, :select, :sensitive, :session_user, :set, :show, :similar, :sin, :sinh, :skip, :smallint, :some, :specific, :specifictype, :sql, :sqlexception, :sqlstate, :sqlwarning, :sqrt, :start, :static, :stddev_pop, :stddev_samp, :submultiset, :subset, :substring, :substring_regex, :succeeds, :sum, :symmetric, :system, :system_time, :system_user, :table, :tablesample, :tan, :tanh, :then, :time, :timestamp, :timezone_hour, :timezone_minute, :to, :trailing, :translate, :translate_regex, :translation, :treat, :trigger, :trim, :trim_array, true, :truncate, :uescape, :union, :unique, :unknown, :unnest, :update, :upper, :user, :using, :value, :values, :value_of, :var_pop, :var_samp, :varbinary, :varchar, :varying, :versioning, :when, :whenever, :where, :width_bucket, :window, :with, :within, :without, :year, :a, :absolute, :action, :ada, :add, :admin, :after, :always, :asc, :assertion, :assignment, :attribute, :attributes, :before, :bernoulli, :breadth, :c, :cascade, :catalog, :catalog_name, :chain, :chaining, :character_set_catalog, :character_set_name, :character_set_schema, :characteristics, :characters, :class_origin, :cobol, :collation, :collation_catalog, :collation_name, :collation_schema, :columns, :column_name, :command_function, :command_function_code, :committed, :conditional, :condition_number, :connection, :connection_name, :constraint_catalog, :constraint_name, :constraint_schema, :constraints, :constructor, :continue, :copartition, :cursor_name, :data, :datetime_interval_code, :datetime_interval_precision, :defaults, :deferrable, :deferred, :defined, :definer, :degree, :depth, :derived, :desc, :descriptor, :diagnostics, :dispatch, :domain, :dynamic_function, :dynamic_function_code, :encoding, :enforced, :error, :exclude, :excluding, :expression, :final, :finish, :first, :flag, :following, :format, :fortran, :found, :fulfill, :g, :general, :generated, :go, :goto, :granted, :hierarchy, :ignore, :immediate, :immediately, :implementation, :including, :increment, :initially, :input, :instance, :instantiable, :instead, :invoker, :isolation, :k, :keep, :key, :keys, :key_member, :key_type, :last, :length, :level, :locator, :m, :map, :matched, :maxvalue, :measures, :message_length, :message_octet_length, :message_text, :minvalue, :more, :mumps, :name, :names, :nested, :nesting, :next, :nfc, :nfd, :nfkc, :nfkd, :normalized, :null_ordering, :nullable, :nulls, :number, :object, :occurrence, :octets, :option, :options, :ordering, :ordinality, :others, :output, :overflow, :overriding, :p, :pad, :parameter_mode, :parameter_name, :parameter_ordinal_position, :parameter_specific_catalog, :parameter_specific_name, :parameter_specific_schema, :partial, :pascal, :pass, :passing, :past, :path, :permute, :pipe, :placing, :plan, :pli, :preceding, :preserve, :prev, :prior, :private, :privileges, :prune, :public, :quotes, :read, :relative, :repeatable, :respect, :restart, :restrict, :returned_cardinality, :returned_length, :returned_octet_length, :returned_sqlstate, :returning, :role, :routine, :routine_catalog, :routine_name, :routine_schema, :row_count, :scalar, :scale, :schema, :schema_name, :scope_catalog, :scope_name, :scope_schema, :section, :security, :self, :semantics, :sequence, :serializable, :server_name, :session, :sets, :simple, :size, :sort_direction, :source, :space, :specific_name, :state, :statement, :string, :structure, :style, :subclass_origin, :t, :table_name, :temporary, :through, :ties, :top_level_count, :transaction, :transaction_active, :transactions_committed, :transactions_rolled_back, :transform, :transforms, :trigger_catalog, :trigger_name, :trigger_schema, :type, :unbounded, :uncommitted, :unconditional, :under, :unmatched, :unnamed, :usage, :user_defined_type_catalog, :user_defined_type_code, :user_defined_type_name, :user_defined_type_schema, :utf16, :utf32, :utf8, :view, :work, :wrapper, :write, :zone, :limit, :ilike, :backward, :forward, :isnull, :notnull]
  defguard is_not(node) when elem(node, 0) == :not and elem(node, 2) == []
  defguard is_join(node) when elem(node, 0) == :join
  defguard is_parens(node) when elem(node, 0) == :parens
  defguard is_operator(node) when elem(node, 0) in ~w[operator :: + - * / ^ % & += -= *= /= %= &= ^-= |*= <=> || as <> <= >= != < > !< !> = like ilike in all any is isnull notnull between]a
  defguard is_of(node) when elem(node, 0) == :of
  defguard is_is(node) when elem(node, 0) == :is
  defguard is_on(node) when elem(node, 0) == :on
  defguard is_select(node) when elem(node, 0) == :select

  def predicate([l, c, r]) when is_boolean(l) and is_conditional(c) and is_boolean(r) do
    {elem(c, 0), elem(c, 1), [l, r]}
  end
  def predicate([l, b]) when is_boolean(b) do
    [{elem(b, 0), elem(b, 1), [l | elem(b, 2)]}]
  end
  def predicate([l, b, r | rest]) when is_boolean(b) or is_operator(b) do
    predicate([{elem(b, 0), elem(b, 1), [l, r]} | rest])
  end
  def predicate([{_, _, _}, node | _] =  unit) when is_comma(node) do
    unit
  end
  def predicate([l, b, r, c | rest]) when is_comma(c) and (is_boolean(b) or is_operator(b)) do
    [{elem(b, 0), elem(b, 1), [l, r]}, c | rest]
  end
  def predicate([l, c, r, c2 | rest]) when is_boolean(l) and is_conditional(c) and is_boolean(r) and is_conditional(c2) do
    predicate([{elem(c, 0), elem(c, 1), [l, r]}, c2 | rest])
  end
  def predicate([f, c, l, b, r, c2 | rest]) when is_boolean(b) and is_conditional(c) and is_conditional(c2) do
    predicate([f, c, {elem(b, 0), elem(b, 1), [l, r]}, c2 | rest])
  end
  def predicate([f, c, l, b, r]) when is_boolean(b) and is_conditional(c) do
    predicate([f, c, {elem(b, 0), elem(b, 1), [l, r]}])
  end
  def predicate([l, b, r, c | rest]) when is_boolean(b) and is_conditional(c) do
    predicate([{elem(b, 0), elem(b, 1), [l, r]}, c | rest])
  end
  def predicate(unit) do
    unit
  end


  def insert_node(node, unit, acc, context, root) when is_parens(node) do
    {[{elem(node, 0), elem(node, 1), parse(elem(node, 2))} | unit], acc, context, root}
  end
  def insert_node(node, [{:in = tag, meta, []}, right, {:using, _, _} = using | unit], acc, context, root) do
    {[{tag, meta, [node, [right, using | unit]]}], acc, context, root}
  end
  def insert_node({:in, _, _} = node, [_, {:using, _, _}|_] = unit, acc, context, root) do
    {[node | unit], acc, context, root}
  end
  def insert_node({:into = tag, meta, _}, [_] = unit, acc, context, root) do
    {[{tag, meta, unit}], acc, context, root}
  end
  def insert_node(node, [n, b, r, c, l | unit], acc, context, root) when is_between(b) and is_and(c) and is_not(n) and is_data_type(r) and is_data_type(l) and is_data_type(node) do
    {[{elem(b, 0), elem(b, 1), [{elem(n, 0), elem(n, 1), [node]}, {elem(c, 0), elem(c, 1), [r, l]}]} | unit], acc, context, root}
  end
  def insert_node(node, [n, b, s, r, c, l | unit], acc, context, root) when is_between(b) and is_and(c) and is_not(n) and is_data_type(r) and is_data_type(l) and is_data_type(node) do
    {[{elem(b, 0), elem(b, 1), [{elem(n, 0), elem(n, 1), [node]}, {elem(s, 0), elem(s, 1), [{elem(c, 0), elem(c, 1), [r, l]}]}]} | unit], acc, context, root}
  end
  def insert_node(node, [b, s, r, c, l | unit], acc, context, root) when is_between(b) and is_and(c) and is_data_type(r) and is_data_type(l) and is_data_type(node) do
    {[{elem(b, 0), elem(b, 1), [node, {elem(s, 0), elem(s, 1), [{elem(c, 0), elem(c, 1), [r, l]}]}]} | unit], acc, context, root}
  end
  def insert_node(node, [b, r, c, l | unit], acc, context, root) when is_between(b) and is_and(c) and is_data_type(r) and is_data_type(l) and is_data_type(node) do
    {[{elem(b, 0), elem(b, 1), [node, {elem(c, 0), elem(c, 1), [r, l]}]} | unit], acc, context, root}
  end
  def insert_node(node, [b, l, c | unit], acc, context, root) when is_data_type(node) and is_operator(b) and is_data_type(l) and is_conditional(c) do
    {[{elem(b, 0), elem(b, 1), [node, l]}, c | unit], acc, context, root}
  end
  def insert_node(node, [r, b, l | unit], acc, context, root) when is_conditional(node) and is_data_type(r) and is_operator(b) and is_data_type(l) do
    {[node, {elem(b, 0), elem(b, 1), [r, l]} | unit], acc, context, root}
  end
  def insert_node(node, [o, l], acc, context, root) when is_data_type(node) and is_operator(o) and is_data_type(l) do
    {[{elem(o, 0), elem(o, 1), [node, l]}], acc, context, root}
  end
  def insert_node(node, [u | unit], acc, context, root) when is_not(node) and elem(u, 0) in ~w[false true unknown null]a do
    {[{elem(node, 0), elem(node, 1), [u]} | unit], acc, context, root}
  end
  def insert_node(node, [u | unit], acc, context, root) when is_not(u) and is_data_type(node) do
    {[{elem(u, 0), elem(u, 1), [node | unit]}], acc, context, root}
  end
  def insert_node({:into = tag, meta, []}, [ident, parens, values], acc, context, root) do
    {[], [{tag, meta, [ident, parens, values]} | acc], context, root}
  end
  def insert_node({tag, meta, []}, [ident, parens], acc, context, root) when tag in ~w[into table]a do
    {[], [{tag, meta, [ident, parens]} | acc], context, root}
  end
  def insert_node({:add = tag, meta, []}, [ident, type], acc, context, root) do
    {[], [{tag, meta, [ident, type]} | acc], context, root}
  end
  def insert_node({:type = tag, meta, []}, [ident, as, type], acc, context, root) do
    {[], [{tag, meta, [{elem(as, 0), elem(as, 1), [ident, type]}]} | acc], context, root}
  end
  def insert_node({tag, meta, []}, [ident], acc, context, root) when tag in ~w[type table]a do
    {[], [{tag, meta, [ident]} | acc], context, root}
  end
  def insert_node({:with = tag, meta, []}, [{:recursive = t,  m, []}, {:ident, _, _} = l, {:parens, _, _} = r, {:as = t2, m2, a}], [], context, root) do
    {[], [], context, root ++ [{tag, meta, [{t2, m2, [{t, m, [l, r]} | a]}]}]}
  end
  def insert_node({:with = tag, meta, []}, [{:ident, _, _} = l, {:parens, _, _} = r, {:as = t2, m2, a}], [], context, root) do
    {[], [], context, root ++ [{tag, meta, [{t2, m2, [[l, r] | a]}]}]}
  end
  def insert_node({tag, meta, []}, unit, acc, context, root) when tag in ~w[by in references]a do
    {[{tag, meta, predicate(unit ++ acc)}], [], context, root}
  end
  def insert_node(node, [n|_] = unit, acc, context, root) when (is_on(n) or is_of(n)) and elem(node, 0) in ~w[select insert update delete truncate references trigger create connect temporary execute usage set alter system maintain]a do
    {[node|unit], acc, context, root}
  end
  def insert_node(node, [_, n|_] = unit, acc, context, root) when is_for(n) and is_from(node) do
    {[node|unit], acc, context, root}
  end
  def insert_node(node, [_, _, _, n|_] = unit, acc, context, root) when is_for(n) and is_select(node) do
    {[node|unit], acc, context, root}
  end
  def insert_node(node, [] = unit, [] = acc, [] = context, root) when elem(node, 0) in ~w[create drop insert alter update delete start set open close commit rollback]a do
    {[node | unit], acc, context, root}
  end
  def insert_node({tag, meta, []}, unit, acc, context, root) when tag in ~w[create drop insert alter update delete start set open close commit rollback]a do
    {[], [], context, [{tag, meta, List.wrap(predicate(unit ++ acc))} | root]}
  end
  def insert_node(node, [n |_] = unit, acc, context, root) when is_grant(node) and elem(n, 0) == :option do
    {[node | unit], acc, context, root}
  end
  def insert_node(node, unit, acc, context, root) when is_grant(node) or is_revoke(node) or is_declare(node) do
    {[], [], context, [{elem(node, 0), elem(node, 1), unit ++ acc ++ root}]}
  end
  def insert_node({:distinct = tag, meta, []}, [{:on, _, _} = on | unit], acc, context, root) do
    {[{tag, meta, [on]} | unit], acc, context, root}
  end
  def insert_node(node, [u | unit], acc, context, root) when is_fetch_dir(node) and elem(u, 0) != :in do
    {[{elem(node, 0), elem(node, 1), [u]}], unit++acc, context, root}
  end
  def insert_node(node, [u | unit], acc, context, root) when is_fetch(node) do
    {[], [], context, [{elem(node, 0), elem(node, 1), [u]} | unit ++ acc ++ root]}
  end
  def insert_node(node, [on], [], context, root) when is_join(node) and is_on(on) do
    {[], [], context, [{elem(node, 0), elem(node, 1), elem(node, 2) ++ [on]} | root]}
  end
  def insert_node(node, [ident, on], [] = acc, context, root) when is_join(node) and is_on(on) do
    {[], acc, context, [{elem(node, 0), elem(node, 1), elem(node, 2) ++ [{elem(on, 0), elem(on, 1), [ident | elem(on, 2)]}]} | root]}
  end
  def insert_node(node, [ident, as, on | unit], [] = acc, context, root) when is_join(node) and is_on(on) do
    {[], acc, context, [{elem(node, 0), elem(node, 1), elem(node, 2) ++ [{elem(on, 0), elem(on, 1), [[ident, as]] ++ elem(on, 2) ++ unit}]} | root]}
  end
  def insert_node(node, [ident, on | unit], [] = acc, context, root) when is_join(node) and is_on(on) do
    {[], acc, context, [{elem(node, 0), elem(node, 1), elem(node, 2) ++ [{elem(on, 0), elem(on, 1), [ident] ++ elem(on, 2) ++ unit}]} | root]}
  end
  def insert_node(node, unit, acc, context, root) when is_join(node) do
    a = elem(node, 2)
    acc = unit ++ acc
    acc = if a == [], do: acc, else: a ++ [acc]
    {[], [], context, [{elem(node, 0), elem(node, 1), acc} | root]}
  end
  def insert_node({tag, meta, []}, unit, acc, context, root) when tag in ~w[select from where group having order limit offset]a do
    {[], [], context, [{tag, meta, List.wrap(predicate(unit ++ acc))} | root]}
  end
  def insert_node(node, unit, acc, context, {:colon, meta, []}) do
    {unit, acc, context, {:colon, meta, [node]}}
  end
  def insert_node(node, [parens | unit], acc, context, root) when is_parens(parens) and is_keyword(node) do
    {[{elem(node, 0), elem(node, 1), [parens]} | unit], acc, context, root}
  end
  def insert_node(node, unit, acc, context, root)  do
    {[node | unit], acc, context, root}
  end

  def parse(tokens) do
    parse(tokens, [], [], [], [])
  end
  def parse([], [], [], [], root) do
    root
  end
  def parse([], unit, acc, [], []) do
    predicate(unit ++ acc)
  end
  def parse([], unit, acc, [], root) do
    predicate(unit ++ acc) ++ root
  end
  def parse([], unit, acc, context, root) when is_tuple(context) do
    [{elem(context, 0), elem(context, 1), [unit ++ acc ++ root, elem(context, 2)]}]
  end
  def parse([node | rest], unit, acc, context, root) when is_comment(node) do
    parse(rest, unit, acc, context, [node | root])
  end
  def parse([{:all, m, _}, node | rest], unit, acc, [], root) when is_combinator(node) do
    parse(rest, [], [], {elem(node, 0), elem(node, 1), [{:all, m, unit ++ acc ++ root}]}, [])
  end
  def parse([node | rest], unit, acc, [], root) when is_combinator(node) do
    parse(rest, [], [], {elem(node, 0), elem(node, 1), unit ++ acc ++ root}, [])
  end
  def parse([node | rest], unit, acc, context, root) when is_colon(node) do
    parse(rest, [], [], context, [{elem(node, 0), elem(node, 1), unit ++ acc ++ root}])
  end
  def parse([ident, from, distinct, n, is, left | rest], unit, acc, context, root) when is_is(is) and is_from(from) and is_distinct(distinct) do
    node = {elem(is, 0), elem(is, 1), [left, {elem(n, 0), elem(n, 1), [{elem(distinct, 0), elem(distinct, 1), [{elem(from, 0), elem(from, 1), [ident]}]}]}]}
    {unit, acc, context, root} = insert_node(node, unit, acc, context, root)
    parse(rest, unit, acc, context, root)
  end
  def parse([ident, from, distinct, is, left | rest], unit, acc, context, root) when is_is(is) and is_from(from) and is_distinct(distinct) do
    node = {elem(is, 0), elem(is, 1), [left, {elem(distinct, 0), elem(distinct, 1), [{elem(from, 0), elem(from, 1), [ident]}]}]}
    {unit, acc, context, root} = insert_node(node, unit, acc, context, root)
    parse(rest, unit, acc, context, root)
  end
  def parse([node | rest], unit, acc, context, root) when is_colon(node) do
    parse(rest, [], [], context, [{elem(node, 0), elem(node, 1), unit ++ acc ++ root}])
  end
  def parse([parens, node | rest], unit, acc, [], root) when is_parens(parens) and is_combinator(node) do
    parse(rest, unit, acc, {elem(node, 0), elem(node, 1), [{elem(parens, 0), elem(parens, 1), parse(elem(parens, 2))}]}, root)
  end
  def parse([node | rest], unit, acc, context, root) when is_comma(node) do
    parse(rest, [], [{elem(node, 0), elem(node, 1), predicate(unit)} | acc], context, root)
  end
  def parse([node | rest], unit, acc, context, root) do
    {unit, acc, context, root} = insert_node(node, unit, acc, context, root)
    parse(rest, unit, acc, context, root)
  end
end