import gleam/list
import gleeunit
import gleeunit/should
import ieee_float.{finite, nan, positive_infinity}
import kmer.{
  type DecodeResult, type DecodedValue, Boolean, Bytes, Float, Integer, Null,
  String, Undefined,
}

pub fn main() {
  gleeunit.main()
}

fn table_test_decode(test_case: BitArray, expected: DecodedValue) {
  kmer.decode(test_case) |> is_value(expected)
}

fn is_value(val: DecodeResult, expected: DecodedValue) {
  should.be_ok(val) |> should.equal(#(expected, <<>>))
}

pub fn decode_immediate_int_test() {
  [
    // Small integers under 24
    #(<<0>>, Integer(0)),
    #(<<10>>, Integer(10)),
    #(<<23>>, Integer(23)),
  ]
  |> table_fn(table_test_decode)
}

pub fn decode_int_test() {
  [
    // 1-byte length (Maj.arg 24)
    #(<<24, 24>>, Integer(24)),
    #(<<24, 100>>, Integer(100)),
    // 2-byte length (Maj.arg 25)
    #(<<25, 1234:16>>, Integer(1234)),
    #(<<25, 12_345:16>>, Integer(12_345)),
    // 3-byte length (Maj.arg 26)
    #(<<26, 1_234_567:32>>, Integer(1_234_567)),
    #(<<26, 999_999_999:32>>, Integer(999_999_999)),
    // 4-byte length (Maj.arg 27)
    #(<<27, 2_099_210_021_019_898_881:64>>, Integer(2_099_210_021_019_898_881)),
    #(<<27, 3:64>>, Integer(3)),
  ]
  |> table_fn(table_test_decode)
}

pub fn decode_negative_int_test() {
  [
    // Immediate negative (under 25)
    #(<<1:3, 0:5>>, Integer(-1)),
    #(<<1:3, 8:5>>, Integer(-9)),
    #(<<1:3, 23:5>>, Integer(-24)),
    // 1-byte length (Maj.arg 24)
    #(<<1:3, 24:5, 24:8>>, Integer(-25)),
    #(<<1:3, 24:5, 100:8>>, Integer(-101)),
    // 2-byte length (Maj.arg 25)
    #(<<1:3, 25:5, 1234:16>>, Integer(-1235)),
    #(<<1:3, 25:5, 12_345:16>>, Integer(-12_346)),
    // 3-byte length (Maj.arg 26)
    #(<<1:3, 26:5, 1_234_567:32>>, Integer(-1_234_568)),
    #(<<1:3, 26:5, 999_999_999:32>>, Integer(-1_000_000_000)),
    // 4-byte length (Maj.arg 27)
    #(
      <<1:3, 27:5, 2_099_210_021_019_898_881:64>>,
      Integer(-2_099_210_021_019_898_882),
    ),
    #(<<1:3, 27:5, 3:64>>, Integer(-4)),
  ]
  |> table_fn(table_test_decode)
}

pub fn decode_simple_test() {
  [
    #(<<7:3, 20:5>>, Boolean(False)),
    #(<<7:3, 21:5>>, Boolean(True)),
    #(<<7:3, 22:5>>, Null),
    #(<<7:3, 23:5>>, Undefined),
  ]
  |> table_fn(table_test_decode)
}

pub fn decode_float_test() {
  [
    #(<<7:3, 25:5, 0x0000:16>>, Float(finite(0.0))),
    #(<<7:3, 25:5, 0x3c00:16>>, Float(finite(1.0))),
    #(<<7:3, 25:5, 0x3e00:16>>, Float(finite(1.5))),
    #(<<7:3, 25:5, 0xc400:16>>, Float(finite(-4.0))),
    #(<<7:3, 25:5, 0x7c00:16>>, Float(positive_infinity())),
    #(<<7:3, 25:5, 0x7e00:16>>, Float(nan())),
    #(<<7:3, 26:5, 0x47c35000:32>>, Float(finite(100_000.0))),
    #(<<7:3, 27:5, 0x3ff199999999999a:64>>, Float(finite(1.1))),
    #(<<7:3, 27:5, 0x7e37e43c8800759c:64>>, Float(finite(1.0e300))),
  ]
  |> table_fn(table_test_decode)
}

pub fn decode_bytestring_test() {
  [
    #(
      <<2:3, 9:5, 10, 11, 12, 13, 14, 15, 16, 17, 18>>,
      Bytes(<<10, 11, 12, 13, 14, 15, 16, 17, 18>>),
    ),
    #(
      <<2:3, 24:5, 8:8, 11, 12, 13, 14, 15, 16, 17, 18>>,
      Bytes(<<11, 12, 13, 14, 15, 16, 17, 18>>),
    ),
  ]
  |> table_fn(table_test_decode)
}

pub fn decode_string_test() {
  [
    #(<<3:3, 11:5, "Hello world">>, String("Hello world")),
    #(
      <<3:3, 24:5, 25:8, "perché siamo fatti così">>,
      String("perché siamo fatti così"),
    ),
  ]
  |> table_fn(table_test_decode)
}

fn table_fn(tests: List(#(a, b)), test_fn: fn(a, b) -> Nil) {
  list.map(tests, fn(t) {
    let #(test_case, expected) = t
    test_fn(test_case, expected)
  })
}