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

test("LOAD - basic function call", async () => {
  const bytecode = toBytecode(`
    LOAD add
    PUSH 5
    PUSH 10
    PUSH 2
    PUSH 0
    CALL
  `)

  const vm = new VM(bytecode)

  // Register a Value-based function
  vm.registerValueFunction('add', (a, b) => {
    return toValue(toNumber(a) + toNumber(b))
  })

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

test("LOAD - function with string manipulation", async () => {
  const bytecode = toBytecode(`
    LOAD concat
    PUSH "hello"
    PUSH "world"
    PUSH 2
    PUSH 0
    CALL
  `)

  const vm = new VM(bytecode)

  vm.registerValueFunction('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("LOAD - async function", async () => {
  const bytecode = toBytecode(`
    LOAD asyncDouble
    PUSH 42
    PUSH 1
    PUSH 0
    CALL
  `)

  const vm = new VM(bytecode)

  vm.registerValueFunction('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("LOAD - function with no arguments", async () => {
  const bytecode = toBytecode(`
    LOAD getAnswer
    PUSH 0
    PUSH 0
    CALL
  `)

  const vm = new VM(bytecode)

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

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

test("LOAD - function with multiple arguments", async () => {
  const bytecode = toBytecode(`
    LOAD sum
    PUSH 2
    PUSH 3
    PUSH 4
    PUSH 3
    PUSH 0
    CALL
  `)

  const vm = new VM(bytecode)

  vm.registerValueFunction('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("LOAD - function returns array", async () => {
  const bytecode = toBytecode(`
    LOAD makeRange
    PUSH 3
    PUSH 1
    PUSH 0
    CALL
  `)

  const vm = new VM(bytecode)

  vm.registerValueFunction('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("LOAD - function not found", async () => {
  const bytecode = toBytecode(`
    LOAD nonexistent
    PUSH 0
    PUSH 0
    CALL
  `)

  const vm = new VM(bytecode)

  expect(vm.run()).rejects.toThrow('Undefined variable: nonexistent')
})

test("LOAD - using result in subsequent operations", async () => {
  const bytecode = toBytecode(`
    LOAD triple
    PUSH 5
    PUSH 1
    PUSH 0
    CALL
    PUSH 10
    ADD
  `)

  const vm = new VM(bytecode)

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

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

test("Native function wrapping - basic sync function with native types", async () => {
  const bytecode = toBytecode(`
    LOAD add
    PUSH 5
    PUSH 10
    PUSH 2
    PUSH 0
    CALL
  `)

  const vm = new VM(bytecode)

  // Register with native TypeScript types - auto-wraps!
  vm.registerFunction('add', (a: number, b: number) => {
    return a + b
  })

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

test("Native function wrapping - async function with native types", async () => {
  const bytecode = toBytecode(`
    LOAD asyncDouble
    PUSH 42
    PUSH 1
    PUSH 0
    CALL
  `)

  const vm = new VM(bytecode)

  // Async native function
  vm.registerFunction('asyncDouble', async (n: number) => {
    await new Promise(resolve => setTimeout(resolve, 1))
    return n * 2
  })

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

test("Native function wrapping - string manipulation", async () => {
  const bytecode = toBytecode(`
    LOAD concat
    PUSH "hello"
    PUSH "world"
    PUSH 2
    PUSH 0
    CALL
  `)

  const vm = new VM(bytecode)

  // Native string function
  vm.registerFunction('concat', (a: string, b: string) => {
    return a + ' ' + b
  })

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

test("Native function wrapping - with default parameters", async () => {
  const bytecode = toBytecode(`
    LOAD ls
    PUSH "/home/user"
    PUSH 1
    PUSH 0
    CALL
  `)

  const vm = new VM(bytecode)

  // Function with default parameter (like NOSE commands)
  vm.registerFunction('ls', (path: string, link = false) => {
    return link ? `listing ${path} with links` : `listing ${path}`
  })

  const result = await vm.run()
  expect(result).toEqual({ type: 'string', value: 'listing /home/user' })
})

test("Native function wrapping - returns array", async () => {
  const bytecode = toBytecode(`
    LOAD makeRange
    PUSH 3
    PUSH 1
    PUSH 0
    CALL
  `)

  const vm = new VM(bytecode)

  // Return native array - auto-converts to Value array
  vm.registerFunction('makeRange', (n: number) => {
    return Array.from({ length: n }, (_, i) => i)
  })

  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("Native function wrapping - returns object (becomes dict)", async () => {
  const bytecode = toBytecode(`
    LOAD makeUser
    PUSH "Alice"
    PUSH 30
    PUSH 2
    PUSH 0
    CALL
  `)

  const vm = new VM(bytecode)

  // Return plain object - auto-converts to dict
  vm.registerFunction('makeUser', (name: string, age: number) => {
    return { name, age }
  })

  const result = await vm.run()
  expect(result.type).toBe('dict')
  if (result.type === 'dict') {
    expect(result.value.get('name')).toEqual(toValue('Alice'))
    expect(result.value.get('age')).toEqual(toValue(30))
  }
})

test("Native function wrapping - mixed with manual Value functions", async () => {
  const bytecode = toBytecode(`
    LOAD nativeAdd
    PUSH 5
    PUSH 1
    PUSH 0
    CALL
    STORE sum
    LOAD manualDouble
    LOAD sum
    PUSH 1
    PUSH 0
    CALL
  `)

  const vm = new VM(bytecode)

  // Native function (auto-wrapped by registerFunction)
  vm.registerFunction('nativeAdd', (n: number) => n + 10)

  // Manual Value function (use registerValueFunction)
  vm.registerValueFunction('manualDouble', (v) => {
    return toValue(toNumber(v) * 2)
  })

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

test("Named arguments - basic named arg", async () => {
  const bytecode = toBytecode(`
    LOAD greet
    PUSH "name"
    PUSH "Alice"
    PUSH 0
    PUSH 1
    CALL
  `)

  const vm = new VM(bytecode)
  vm.registerFunction('greet', (name: string) => `Hello, ${name}!`)

  const result = await vm.run()
  expect(result).toEqual({ type: 'string', value: 'Hello, Alice!' })
})

test("Named arguments - mixed positional and named", async () => {
  const bytecode = toBytecode(`
    LOAD makeUser
    PUSH "Alice"
    PUSH "age"
    PUSH 30
    PUSH 1
    PUSH 1
    CALL
  `)

  const vm = new VM(bytecode)
  vm.registerFunction('makeUser', (name: string, age: number) => {
    return { name, age }
  })

  const result = await vm.run()
  expect(result.type).toBe('dict')
  if (result.type === 'dict') {
    expect(result.value.get('name')).toEqual(toValue('Alice'))
    expect(result.value.get('age')).toEqual(toValue(30))
  }
})

test("Named arguments - named takes priority over positional", async () => {
  const bytecode = toBytecode(`
    LOAD add
    PUSH 100
    PUSH "a"
    PUSH 5
    PUSH "b"
    PUSH 10
    PUSH 1
    PUSH 2
    CALL
  `)

  const vm = new VM(bytecode)
  vm.registerFunction('add', (a: number, b: number) => a + b)

  const result = await vm.run()
  // Named args should be: a=5, b=10
  // Positional arg (100) is provided but named args take priority
  expect(result).toEqual({ type: 'number', value: 15 })
})

test("Named arguments - with defaults", async () => {
  const bytecode = toBytecode(`
    LOAD greet
    PUSH "name"
    PUSH "Bob"
    PUSH 0
    PUSH 1
    CALL
  `)

  const vm = new VM(bytecode)
  vm.registerFunction('greet', (name: string, greeting = 'Hello') => {
    return `${greeting}, ${name}!`
  })

  const result = await vm.run()
  expect(result).toEqual({ type: 'string', value: 'Hello, Bob!' })
})

test("Named arguments - override defaults with named args", async () => {
  const bytecode = toBytecode(`
    LOAD greet
    PUSH "name"
    PUSH "Bob"
    PUSH "greeting"
    PUSH "Hi"
    PUSH 0
    PUSH 2
    CALL
  `)

  const vm = new VM(bytecode)
  vm.registerFunction('greet', (name: string, greeting = 'Hello') => {
    return `${greeting}, ${name}!`
  })

  const result = await vm.run()
  expect(result).toEqual({ type: 'string', value: 'Hi, Bob!' })
})

test("Named arguments - with variadic function", async () => {
  const bytecode = toBytecode(`
    LOAD sum
    PUSH 1
    PUSH 2
    PUSH 3
    PUSH "multiplier"
    PUSH 2
    PUSH 3
    PUSH 1
    CALL
  `)

  const vm = new VM(bytecode)
  vm.registerFunction('sum', (multiplier: number, ...nums: number[]) => {
    const total = nums.reduce((acc, n) => acc + n, 0)
    return total * multiplier
  })

  const result = await vm.run()
  expect(result).toEqual({ type: 'number', value: 12 }) // (1 + 2 + 3) * 2
})

test("Named arguments - works with both wrapped and non-wrapped functions", async () => {
  const bytecode = toBytecode(`
    ; Test wrapped function (registerFunction)
    LOAD wrappedAdd
    PUSH "a"
    PUSH 5
    PUSH "b"
    PUSH 10
    PUSH 0
    PUSH 2
    CALL
    STORE result1

    ; Test non-wrapped function (registerValueFunction)
    LOAD valueAdd
    PUSH "a"
    PUSH 3
    PUSH "b"
    PUSH 7
    PUSH 0
    PUSH 2
    CALL
    STORE result2

    ; Return both results
    LOAD result1
    LOAD result2
    ADD
  `)

  const vm = new VM(bytecode)

  // Wrapped function - auto-converts types
  vm.registerFunction('wrappedAdd', (a: number, b: number) => a + b)

  // Non-wrapped function - works directly with Values
  vm.registerValueFunction('valueAdd', (a, b) => {
    return toValue(toNumber(a) + toNumber(b))
  })

  const result = await vm.run()
  expect(result).toEqual({ type: 'number', value: 25 }) // 15 + 10
})

test("@named pattern - basic atNamed parameter", async () => {
  const bytecode = toBytecode(`
    LOAD greet
    PUSH "name"
    PUSH "Alice"
    PUSH "greeting"
    PUSH "Hi"
    PUSH "extra"
    PUSH "value"
    PUSH 0
    PUSH 3
    CALL
  `)

  const vm = new VM(bytecode)
  vm.registerFunction('greet', (atNamed: any = {}) => {
    const name = atNamed.name || 'Unknown'
    const greeting = atNamed.greeting || 'Hello'
    const extra = atNamed.extra || ''
    return `${greeting}, ${name}! Extra: ${extra}`
  })

  const result = await vm.run()
  expect(result).toEqual({ type: 'string', value: 'Hi, Alice! Extra: value' })
})

test('@named pattern - atNamed parameters with varadic args', async () => {
  const bytecode = toBytecode(`
    TRY_LOAD cmd
    TRY_LOAD rest1
    TRY_LOAD rest2
    PUSH 'named'
    TRY_LOAD named-value
    PUSH 2
    PUSH 1
    CALL
    HALT
  `)

  const vm = new VM(bytecode)
  vm.registerFunction('cmd', (atNamed: any = {}, ...rest: string[]) => {
    return { rest, namedArg: atNamed['named'] }
  })

  const result = await vm.run()
  expect(result.type).toBe('dict')
  if (!(result.value instanceof Map)) throw new Error('Expected dict')
  expect(result.value.get('rest')).toEqual(toValue(['rest1', 'rest2']))
  expect(result.value.get('namedArg')).toEqual(toValue('named-value'))
})

test("@named pattern - mixed positional and atOptions", async () => {
  const bytecode = toBytecode(`
    LOAD configure
    PUSH "app"
    PUSH "debug"
    PUSH true
    PUSH "port"
    PUSH 8080
    PUSH 1
    PUSH 2
    CALL
  `)

  const vm = new VM(bytecode)
  vm.registerFunction('configure', (name: string, atOptions: any = {}) => {
    return {
      name,
      debug: atOptions.debug || false,
      port: atOptions.port || 3000
    }
  })

  const result = await vm.run()
  expect(result.type).toBe('dict')
  if (result.type === 'dict') {
    expect(result.value.get('name')).toEqual(toValue('app'))
    expect(result.value.get('debug')).toEqual(toValue(true))
    expect(result.value.get('port')).toEqual(toValue(8080))
  }
})

test("@named pattern - with default empty object", async () => {
  const bytecode = toBytecode(`
    LOAD build
    PUSH "project"
    PUSH 1
    PUSH 0
    CALL
  `)

  const vm = new VM(bytecode)
  vm.registerFunction('build', (name: string, atConfig: any = {}) => {
    return `Building ${name} with ${Object.keys(atConfig).length} options`
  })

  const result = await vm.run()
  expect(result).toEqual({ type: 'string', value: 'Building project with 0 options' })
})

test("@named pattern - collects only unmatched named args", async () => {
  const bytecode = toBytecode(`
    LOAD process
    PUSH "file"
    PUSH "test.txt"
    PUSH "mode"
    PUSH "read"
    PUSH "extra1"
    PUSH "value1"
    PUSH "extra2"
    PUSH "value2"
    PUSH 0
    PUSH 4
    CALL
  `)

  const vm = new VM(bytecode)
  vm.registerFunction('process', (file: string, mode: string, atOptions: any = {}) => {
    // file and mode are matched, extra1 and extra2 go to atOptions
    return {
      file,
      mode,
      optionCount: Object.keys(atOptions).length,
      extra1: atOptions.extra1,
      extra2: atOptions.extra2
    }
  })

  const result = await vm.run()
  expect(result.type).toBe('dict')
  if (result.type === 'dict') {
    expect(result.value.get('file')).toEqual(toValue('test.txt'))
    expect(result.value.get('mode')).toEqual(toValue('read'))
    expect(result.value.get('optionCount')).toEqual(toValue(2))
    expect(result.value.get('extra1')).toEqual(toValue('value1'))
    expect(result.value.get('extra2')).toEqual(toValue('value2'))
  }
})

test("Native function receives Reef function as callback - basic map", async () => {
  const bytecode = toBytecode(`
    ; Define a Reef function that doubles a number
    MAKE_FUNCTION (x) .double_body
    STORE double
    JUMP .skip_double
    .double_body:
      LOAD x
      PUSH 2
      MUL
      RETURN
    .skip_double:

    ; Call native 'map' with array and Reef function
    LOAD map
    PUSH 1
    PUSH 2
    PUSH 3
    MAKE_ARRAY #3
    LOAD double
    PUSH 2
    PUSH 0
    CALL
  `)

  const vm = new VM(bytecode)

  // Native function that takes an array and a callback
  vm.registerFunction('map', async (array: any[], callback: Function) => {
    const results = []
    for (const item of array) {
      results.push(await callback(item))
    }
    return results
  })

  const result = await vm.run()
  expect(result.type).toBe('array')
  if (result.type === 'array') {
    console.log(result.value)
    expect(result.value).toEqual([
      toValue(2),
      toValue(4),
      toValue(6)
    ])
  } else {
    expect(true).toBe(false)
  }
})

test("Native function receives Reef function - iterator pattern with each", async () => {
  const bytecode = toBytecode(`
    ; Define a Reef function that adds to a sum
    MAKE_FUNCTION (item) .add_to_sum_body
    STORE add_to_sum
    JUMP .skip_add_to_sum
    .add_to_sum_body:
      LOAD sum
      LOAD item
      ADD
      STORE sum
      RETURN
    .skip_add_to_sum:

    ; Initialize sum
    PUSH 0
    STORE sum

    ; Call native 'each' with array and Reef function
    LOAD each
    PUSH 10
    PUSH 20
    PUSH 30
    MAKE_ARRAY #3
    LOAD add_to_sum
    PUSH 2
    PUSH 0
    CALL

    ; Return the sum
    LOAD sum
  `)

  const vm = new VM(bytecode)

  // Native 'each' function (like Ruby's each)
  vm.registerFunction('each', async (array: any[], callback: Function) => {
    for (const item of array) {
      await callback(item)
    }
    return null
  })

  const result = await vm.run()
  expect(result).toEqual({ type: 'number', value: 60 })
})

test("Native function receives Reef function - filter pattern", async () => {
  const bytecode = toBytecode(`
    ; Define a Reef function that checks if number > 5
    MAKE_FUNCTION (x) .is_greater_body
    STORE is_greater
    JUMP .skip_is_greater
    .is_greater_body:
      LOAD x
      PUSH 5
      GT
      RETURN
    .skip_is_greater:

    ; Call native 'filter' with array and Reef function
    LOAD filter
    PUSH 3
    PUSH 7
    PUSH 2
    PUSH 9
    PUSH 1
    MAKE_ARRAY #5
    LOAD is_greater
    PUSH 2
    PUSH 0
    CALL
  `)

  const vm = new VM(bytecode)

  // Native filter function
  vm.registerFunction('filter', async (array: any[], predicate: Function) => {
    const results = []
    for (const item of array) {
      if (await predicate(item)) {
        results.push(item)
      }
    }
    return results
  })

  const result = await vm.run()
  expect(result.type).toBe('array')
  if (result.type === 'array') {
    expect(result.value).toEqual([
      toValue(7),
      toValue(9)
    ])
  }
})

test("Native function receives Reef function - closure capturing", async () => {
  const bytecode = toBytecode(`
    ; Store a multiplier in scope
    PUSH 10
    STORE multiplier

    ; Define a Reef function that uses the closure variable
    MAKE_FUNCTION (x) .multiply_body
    STORE multiply_by_ten
    JUMP .skip_multiply
    .multiply_body:
      LOAD x
      LOAD multiplier
      MUL
      RETURN
    .skip_multiply:

    ; Call native 'map' with the closure function
    LOAD map
    PUSH 1
    PUSH 2
    PUSH 3
    MAKE_ARRAY #3
    LOAD multiply_by_ten
    PUSH 2
    PUSH 0
    CALL
  `)

  const vm = new VM(bytecode)

  vm.registerFunction('map', async (array: any[], callback: Function) => {
    const results = []
    for (const item of array) {
      results.push(await callback(item))
    }
    return results
  })

  const result = await vm.run()
  expect(result.type).toBe('array')
  if (result.type === 'array') {
    expect(result.value).toEqual([
      toValue(10),
      toValue(20),
      toValue(30)
    ])
  }
})

test("Native function receives Reef function - multiple arguments", async () => {
  const bytecode = toBytecode(`
    ; Define a Reef function that takes two args
    MAKE_FUNCTION (a b) .add_body
    STORE add
    JUMP .skip_add
    .add_body:
      LOAD a
      LOAD b
      ADD
      RETURN
    .skip_add:

    ; Call native 'reduce' with array, initial value, and Reef function
    LOAD reduce
    PUSH 1
    PUSH 2
    PUSH 3
    PUSH 4
    MAKE_ARRAY #4
    PUSH 0
    LOAD add
    PUSH 3
    PUSH 0
    CALL
  `)

  const vm = new VM(bytecode)

  // Native reduce function (accumulator, array, callback)
  vm.registerFunction('reduce', async (array: any[], initial: any, callback: Function) => {
    let acc = initial
    for (const item of array) {
      acc = await callback(acc, item)
    }
    return acc
  })

  const result = await vm.run()
  expect(result).toEqual({ type: 'number', value: 10 })
})

test("Native function receives Reef function - returns non-primitive", async () => {
  const bytecode = toBytecode(`
    ; Define a Reef function that returns a dict
    MAKE_FUNCTION (name) .make_user_body
    STORE make_user
    JUMP .skip_make_user
    .make_user_body:
      PUSH "name"
      LOAD name
      PUSH "active"
      PUSH true
      MAKE_DICT #2
      RETURN
    .skip_make_user:

    ; Call native 'map' to create users
    LOAD map
    PUSH "Alice"
    PUSH "Bob"
    MAKE_ARRAY #2
    LOAD make_user
    PUSH 2
    PUSH 0
    CALL
  `)

  const vm = new VM(bytecode)

  vm.registerFunction('map', async (array: any[], callback: Function) => {
    const results = []
    for (const item of array) {
      results.push(await callback(item))
    }
    return results
  })

  const result = await vm.run()
  expect(result.type).toBe('array')
  if (result.type === 'array') {
    expect(result.value.length).toBe(2)

    const first = result.value[0]
    expect(first?.type).toBe('dict')
    if (first?.type === 'dict') {
      expect(first.value.get('name')).toEqual(toValue('Alice'))
      expect(first.value.get('active')).toEqual(toValue(true))
    }

    const second = result.value[1]
    expect(second?.type).toBe('dict')
    if (second?.type === 'dict') {
      expect(second.value.get('name')).toEqual(toValue('Bob'))
      expect(second.value.get('active')).toEqual(toValue(true))
    }
  }
})