import { test, expect } from "bun:test"
import { VM } from "#vm"
import { toBytecode } from "#bytecode"
import { toValue, toNumber, toString } from "#value"

test("CALL_NATIVE - basic function call", async () => {
  const bytecode = toBytecode(`
    PUSH 5
    PUSH 10
    CALL_NATIVE add
  `)

  const vm = new VM(bytecode)

  // Register a native function
  vm.registerFunction('add', (a, b) => {
    return toValue(toNumber(a) + toNumber(b))
  })

  const result = await vm.run()
  expect(result).toEqual({ type: 'number', value: 15 })
})

test("CALL_NATIVE - function with string manipulation", async () => {
  const bytecode = toBytecode(`
    PUSH "hello"
    PUSH "world"
    CALL_NATIVE concat
  `)

  const vm = new VM(bytecode)

  vm.registerFunction('concat', (a, b) => {
    const aStr = a.type === 'string' ? a.value : toString(a)
    const bStr = b.type === 'string' ? b.value : toString(b)
    return toValue(aStr + ' ' + bStr)
  })

  const result = await vm.run()
  expect(result).toEqual({ type: 'string', value: 'hello world' })
})

test("CALL_NATIVE - async function", async () => {
  const bytecode = toBytecode(`
    PUSH 42
    CALL_NATIVE asyncDouble
  `)

  const vm = new VM(bytecode)

  vm.registerFunction('asyncDouble', async (a) => {
    // Simulate async operation
    await new Promise(resolve => setTimeout(resolve, 1))
    return toValue(toNumber(a) * 2)
  })

  const result = await vm.run()
  expect(result).toEqual({ type: 'number', value: 84 })
})

test("CALL_NATIVE - function with no arguments", async () => {
  const bytecode = toBytecode(`
    CALL_NATIVE getAnswer
  `)

  const vm = new VM(bytecode)

  vm.registerFunction('getAnswer', () => {
    return toValue(42)
  })

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

test("CALL_NATIVE - function with multiple arguments", async () => {
  const bytecode = toBytecode(`
    PUSH 2
    PUSH 3
    PUSH 4
    CALL_NATIVE sum
  `)

  const vm = new VM(bytecode)

  vm.registerFunction('sum', (...args) => {
    const total = args.reduce((acc, val) => acc + toNumber(val), 0)
    return toValue(total)
  })

  const result = await vm.run()
  expect(result).toEqual({ type: 'number', value: 9 })
})

test("CALL_NATIVE - function returns array", async () => {
  const bytecode = toBytecode(`
    PUSH 3
    CALL_NATIVE makeRange
  `)

  const vm = new VM(bytecode)

  vm.registerFunction('makeRange', (n) => {
    const count = toNumber(n)
    const arr = []
    for (let i = 0; i < count; i++) {
      arr.push(toValue(i))
    }
    return { type: 'array', value: arr }
  })

  const result = await vm.run()
  expect(result.type).toBe('array')
  if (result.type === 'array') {
    expect(result.value.length).toBe(3)
    expect(result.value).toEqual([
      toValue(0),
      toValue(1),
      toValue(2)
    ])
  }
})

test("CALL_NATIVE - function not found", async () => {
  const bytecode = toBytecode(`
    CALL_NATIVE nonexistent
  `)

  const vm = new VM(bytecode)

  await expect(vm.run()).rejects.toThrow('CALL_NATIVE: function not found: nonexistent')
})

test("CALL_NATIVE - using result in subsequent operations", async () => {
  const bytecode = toBytecode(`
    PUSH 5
    CALL_NATIVE triple
    PUSH 10
    ADD
  `)

  const vm = new VM(bytecode)

  vm.registerFunction('triple', (n) => {
    return toValue(toNumber(n) * 3)
  })

  const result = await vm.run()
  expect(result).toEqual({ type: 'number', value: 25 })
})