import { test, expect } from "bun:test"
import { toBytecode } from "#bytecode"
import { OpCode } from "#opcode"
import { VM } from "#vm"

test("string compilation", () => {
  const str = `
  PUSH 1
  PUSH 5
  ADD
`
  expect(toBytecode(str)).toEqual({
    instructions: [
      { op: OpCode.PUSH, operand: 0 },
      { op: OpCode.PUSH, operand: 1 },
      { op: OpCode.ADD },
    ],
    constants: [
      { type: 'number', value: 1 },
      { type: 'number', value: 5 }
    ]
  })
})


test("MAKE_FUNCTION - basic function", async () => {
  const bytecode = toBytecode(`
    MAKE_FUNCTION () #3
    CALL #0
    HALT
    PUSH 42
    RETURN
  `)

  const vm = new VM(bytecode)
  const result = await vm.run()
  expect(result).toEqual({ type: 'number', value: 42 })
})

test("MAKE_FUNCTION - function with parameters", async () => {
  const bytecode = toBytecode(`
    MAKE_FUNCTION (x y) #5
    PUSH 10
    PUSH 20
    CALL #2
    HALT
    LOAD x
    LOAD y
    ADD
    RETURN
  `)

  const vm = new VM(bytecode)
  const result = await vm.run()
  expect(result).toEqual({ type: 'number', value: 30 })
})

test("MAKE_FUNCTION - function with default parameters", async () => {
  const bytecode = toBytecode(`
    MAKE_FUNCTION (x y=100) #4
    PUSH 10
    CALL #1
    HALT
    LOAD x
    LOAD y
    ADD
    RETURN
  `)

  const vm = new VM(bytecode)
  const result = await vm.run()
  expect(result).toEqual({ type: 'number', value: 110 })
})

test("MAKE_FUNCTION - tail recursive countdown", async () => {
  const bytecode = toBytecode(`
    MAKE_FUNCTION (n) #6
    STORE countdown
    LOAD countdown
    PUSH 5
    CALL #1
    HALT
    LOAD n
    PUSH 0
    EQ
    JUMP_IF_FALSE #2
    PUSH "done"
    RETURN
    LOAD countdown
    LOAD n
    PUSH 1
    SUB
    TAIL_CALL #1
  `)

  const vm = new VM(bytecode)
  const result = await vm.run()
  expect(result).toEqual({ type: 'string', value: 'done' })
})

test("MAKE_FUNCTION - multiple default values", async () => {
  const bytecode = toBytecode(`
    MAKE_FUNCTION (a=1 b=2 c=3) #3
    CALL #0
    HALT
    LOAD a
    LOAD b
    LOAD c
    ADD
    ADD
    RETURN
  `)

  const vm = new VM(bytecode)
  const result = await vm.run()
  expect(result).toEqual({ type: 'number', value: 6 })
})

test("MAKE_FUNCTION - default with string", async () => {
  const bytecode = toBytecode(`
    MAKE_FUNCTION (name="World") #3
    CALL #0
    HALT
    LOAD name
    RETURN
  `)

  const vm = new VM(bytecode)
  const result = await vm.run()
  expect(result).toEqual({ type: 'string', value: 'World' })
})