import { test, expect } from "bun:test"
import { VM } from "#vm"
import { OpCode } from "#opcode"
import { toValue, toNumber } from "#value"

test("CALL_TYPESCRIPT - basic function call", async () => {
  const vm = new VM({
    instructions: [
      { op: OpCode.PUSH, operand: 0 },              // push 5
      { op: OpCode.PUSH, operand: 1 },              // push 10
      { op: OpCode.CALL_TYPESCRIPT, operand: 'add' }, // call TypeScript 'add'
      { op: OpCode.HALT }
    ],
    constants: [
      toValue(5),
      toValue(10)
    ]
  })

  // Register a TypeScript 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_TYPESCRIPT - function with string manipulation", async () => {
  const vm = new VM({
    instructions: [
      { op: OpCode.PUSH, operand: 0 },                    // push "hello"
      { op: OpCode.PUSH, operand: 1 },                    // push "world"
      { op: OpCode.CALL_TYPESCRIPT, operand: 'concat' },  // call TypeScript 'concat'
      { op: OpCode.HALT }
    ],
    constants: [
      toValue("hello"),
      toValue("world")
    ]
  })

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

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

test("CALL_TYPESCRIPT - async function", async () => {
  const vm = new VM({
    instructions: [
      { op: OpCode.PUSH, operand: 0 },                      // push 42
      { op: OpCode.CALL_TYPESCRIPT, operand: 'asyncDouble' }, // call async TypeScript function
      { op: OpCode.HALT }
    ],
    constants: [
      toValue(42)
    ]
  })

  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_TYPESCRIPT - function with no arguments", async () => {
  const vm = new VM({
    instructions: [
      { op: OpCode.CALL_TYPESCRIPT, operand: 'getAnswer' },  // call with empty stack
      { op: OpCode.HALT }
    ],
    constants: []
  })

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

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

test("CALL_TYPESCRIPT - function with multiple arguments", async () => {
  const vm = new VM({
    instructions: [
      { op: OpCode.PUSH, operand: 0 },              // push 2
      { op: OpCode.PUSH, operand: 1 },              // push 3
      { op: OpCode.PUSH, operand: 2 },              // push 4
      { op: OpCode.CALL_TYPESCRIPT, operand: 'sum' }, // call TypeScript 'sum'
      { op: OpCode.HALT }
    ],
    constants: [
      toValue(2),
      toValue(3),
      toValue(4)
    ]
  })

  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_TYPESCRIPT - function returns array", async () => {
  const vm = new VM({
    instructions: [
      { op: OpCode.PUSH, operand: 0 },                       // push 3
      { op: OpCode.CALL_TYPESCRIPT, operand: 'makeRange' },  // call TypeScript 'makeRange'
      { op: OpCode.HALT }
    ],
    constants: [
      toValue(3)
    ]
  })

  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_TYPESCRIPT - function not found", async () => {
  const vm = new VM({
    instructions: [
      { op: OpCode.CALL_TYPESCRIPT, operand: 'nonexistent' }
    ],
    constants: []
  })

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

test("CALL_TYPESCRIPT - using result in subsequent operations", async () => {
  const vm = new VM({
    instructions: [
      { op: OpCode.PUSH, operand: 0 },                      // push 5
      { op: OpCode.CALL_TYPESCRIPT, operand: 'triple' },    // call TypeScript 'triple' -> 15
      { op: OpCode.PUSH, operand: 1 },                      // push 10
      { op: OpCode.ADD },                                   // 15 + 10 = 25
      { op: OpCode.HALT }
    ],
    constants: [
      toValue(5),
      toValue(10)
    ]
  })

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

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