import { test, expect, describe } from "bun:test"
import { run } from "#index"
import { toBytecode } from "#bytecode"

describe("ADD", () => {
  test("add two numbers", async () => {
    const str = `
    PUSH 1
    PUSH 5
    ADD
  `
    expect(await run(toBytecode(str))).toEqual({ type: 'number', value: 6 })

    const str2 = `
    PUSH 100
    PUSH 500
    ADD
  `
    expect(await run(toBytecode(str2))).toEqual({ type: 'number', value: 600 })
  })

  test("concatenate two strings", async () => {
    const str = `
    PUSH "hello"
    PUSH " world"
    ADD
  `
    expect(await run(toBytecode(str))).toEqual({ type: 'string', value: 'hello world' })

    const str2 = `
    PUSH "foo"
    PUSH "bar"
    ADD
  `
    expect(await run(toBytecode(str2))).toEqual({ type: 'string', value: 'foobar' })
  })

  test("concatenate string with number", async () => {
    const str = `
    PUSH "count: "
    PUSH 42
    ADD
  `
    expect(await run(toBytecode(str))).toEqual({ type: 'string', value: 'count: 42' })

    const str2 = `
    PUSH 100
    PUSH " items"
    ADD
  `
    expect(await run(toBytecode(str2))).toEqual({ type: 'string', value: '100 items' })
  })

  test("concatenate string with boolean", async () => {
    const str = `
    PUSH "result: "
    PUSH true
    ADD
  `
    expect(await run(toBytecode(str))).toEqual({ type: 'string', value: 'result: true' })

    const str2 = `
    PUSH false
    PUSH " value"
    ADD
  `
    expect(await run(toBytecode(str2))).toEqual({ type: 'string', value: 'false value' })
  })

  test("concatenate string with null", async () => {
    const str = `
    PUSH "value: "
    PUSH null
    ADD
  `
    expect(await run(toBytecode(str))).toEqual({ type: 'string', value: 'value: null' })
  })

  test("concatenate multiple strings in sequence", async () => {
    const str = `
    PUSH "hello"
    PUSH " "
    ADD
    PUSH "world"
    ADD
    PUSH "!"
    ADD
  `
    expect(await run(toBytecode(str))).toEqual({ type: 'string', value: 'hello world!' })
  })

  test("mixed arithmetic and string concatenation", async () => {
    const str = `
    PUSH "Result: "
    PUSH 10
    PUSH 5
    ADD
    ADD
  `
    expect(await run(toBytecode(str))).toEqual({ type: 'string', value: 'Result: 15' })
  })

  test("concatenate two arrays", async () => {
    const bytecode = toBytecode([
      ["PUSH", 1],
      ["PUSH", 2],
      ["PUSH", 3],
      ["MAKE_ARRAY", 3],
      ["PUSH", 4],
      ["MAKE_ARRAY", 1],
      ["ADD"],
      ["HALT"]
    ])

    const result = await run(bytecode)
    expect(result.type).toBe('array')
    if (result.type === 'array') {
      expect(result.value.length).toBe(4)
      expect(result.value[0]).toEqual({ type: 'number', value: 1 })
      expect(result.value[1]).toEqual({ type: 'number', value: 2 })
      expect(result.value[2]).toEqual({ type: 'number', value: 3 })
      expect(result.value[3]).toEqual({ type: 'number', value: 4 })
    }
  })

  test("concatenate empty arrays", async () => {
    const bytecode = toBytecode([
      ["MAKE_ARRAY", 0],
      ["PUSH", 1],
      ["PUSH", 2],
      ["MAKE_ARRAY", 2],
      ["ADD"],
      ["HALT"]
    ])

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

  test("concatenate multiple arrays in sequence", async () => {
    const bytecode = toBytecode([
      ["PUSH", 1],
      ["MAKE_ARRAY", 1],
      ["PUSH", 2],
      ["MAKE_ARRAY", 1],
      ["ADD"],
      ["PUSH", 3],
      ["MAKE_ARRAY", 1],
      ["ADD"],
      ["HALT"]
    ])

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

  test("concatenate arrays with different types", async () => {
    const bytecode = toBytecode([
      ["PUSH", 1],
      ["PUSH", "hello"],
      ["MAKE_ARRAY", 2],
      ["PUSH", true],
      ["PUSH", null],
      ["MAKE_ARRAY", 2],
      ["ADD"],
      ["HALT"]
    ])

    const result = await run(bytecode)
    expect(result.type).toBe('array')
    if (result.type === 'array') {
      expect(result.value.length).toBe(4)
      expect(result.value[0]).toEqual({ type: 'number', value: 1 })
      expect(result.value[1]).toEqual({ type: 'string', value: 'hello' })
      expect(result.value[2]).toEqual({ type: 'boolean', value: true })
      expect(result.value[3]).toEqual({ type: 'null', value: null })
    }
  })

  test("concatenate arrays containing nested arrays", async () => {
    const bytecode = toBytecode([
      ["PUSH", 1],
      ["PUSH", 2],
      ["MAKE_ARRAY", 2],
      ["MAKE_ARRAY", 1],
      ["PUSH", 3],
      ["MAKE_ARRAY", 1],
      ["ADD"],
      ["HALT"]
    ])

    const result = await run(bytecode)
    expect(result.type).toBe('array')
    if (result.type === 'array') {
      expect(result.value.length).toBe(2)
      // First element is nested array [1, 2]
      expect(result.value[0]?.type).toBe('array')
      if (result.value[0]?.type === 'array') {
        expect(result.value[0].value.length).toBe(2)
        expect(result.value[0].value[0]).toEqual({ type: 'number', value: 1 })
        expect(result.value[0].value[1]).toEqual({ type: 'number', value: 2 })
      }
      // Second element is 3
      expect(result.value[1]).toEqual({ type: 'number', value: 3 })
    }
  })

  test("merge two dicts", async () => {
    const bytecode = toBytecode([
      ["PUSH", "a"],
      ["PUSH", 1],
      ["MAKE_DICT", 1],
      ["PUSH", "b"],
      ["PUSH", 2],
      ["MAKE_DICT", 1],
      ["ADD"],
      ["HALT"]
    ])

    const result = await run(bytecode)
    expect(result.type).toBe('dict')
    if (result.type === 'dict') {
      expect(result.value.size).toBe(2)
      expect(result.value.get('a')).toEqual({ type: 'number', value: 1 })
      expect(result.value.get('b')).toEqual({ type: 'number', value: 2 })
    }
  })

  test("merge dicts with overlapping keys (second overwrites)", async () => {
    const bytecode = toBytecode([
      ["PUSH", "a"],
      ["PUSH", 1],
      ["PUSH", "b"],
      ["PUSH", 2],
      ["MAKE_DICT", 2],
      ["PUSH", "b"],
      ["PUSH", 99],
      ["PUSH", "c"],
      ["PUSH", 3],
      ["MAKE_DICT", 2],
      ["ADD"],
      ["HALT"]
    ])

    const result = await run(bytecode)
    expect(result.type).toBe('dict')
    if (result.type === 'dict') {
      expect(result.value.size).toBe(3)
      expect(result.value.get('a')).toEqual({ type: 'number', value: 1 })
      expect(result.value.get('b')).toEqual({ type: 'number', value: 99 }) // overwritten
      expect(result.value.get('c')).toEqual({ type: 'number', value: 3 })
    }
  })

  test("merge empty dicts", async () => {
    const bytecode = toBytecode([
      ["MAKE_DICT", 0],
      ["PUSH", "x"],
      ["PUSH", 42],
      ["MAKE_DICT", 1],
      ["ADD"],
      ["HALT"]
    ])

    const result = await run(bytecode)
    expect(result.type).toBe('dict')
    if (result.type === 'dict') {
      expect(result.value.size).toBe(1)
      expect(result.value.get('x')).toEqual({ type: 'number', value: 42 })
    }
  })

  test("merge multiple dicts in sequence", async () => {
    const bytecode = toBytecode([
      ["PUSH", "a"],
      ["PUSH", 1],
      ["MAKE_DICT", 1],
      ["PUSH", "b"],
      ["PUSH", 2],
      ["MAKE_DICT", 1],
      ["ADD"],
      ["PUSH", "c"],
      ["PUSH", 3],
      ["MAKE_DICT", 1],
      ["ADD"],
      ["HALT"]
    ])

    const result = await run(bytecode)
    expect(result.type).toBe('dict')
    if (result.type === 'dict') {
      expect(result.value.size).toBe(3)
      expect(result.value.get('a')).toEqual({ type: 'number', value: 1 })
      expect(result.value.get('b')).toEqual({ type: 'number', value: 2 })
      expect(result.value.get('c')).toEqual({ type: 'number', value: 3 })
    }
  })

  test("merge dicts with different value types", async () => {
    const bytecode = toBytecode([
      ["PUSH", "num"],
      ["PUSH", 42],
      ["PUSH", "str"],
      ["PUSH", "hello"],
      ["MAKE_DICT", 2],
      ["PUSH", "bool"],
      ["PUSH", true],
      ["PUSH", "null"],
      ["PUSH", null],
      ["MAKE_DICT", 2],
      ["ADD"],
      ["HALT"]
    ])

    const result = await run(bytecode)
    expect(result.type).toBe('dict')
    if (result.type === 'dict') {
      expect(result.value.size).toBe(4)
      expect(result.value.get('num')).toEqual({ type: 'number', value: 42 })
      expect(result.value.get('str')).toEqual({ type: 'string', value: 'hello' })
      expect(result.value.get('bool')).toEqual({ type: 'boolean', value: true })
      expect(result.value.get('null')).toEqual({ type: 'null', value: null })
    }
  })

  test("merge dicts with nested structures", async () => {
    const bytecode = toBytecode([
      ["PUSH", "a"],
      ["PUSH", 1],
      ["PUSH", 2],
      ["MAKE_ARRAY", 2],
      ["MAKE_DICT", 1],
      ["PUSH", "b"],
      ["PUSH", "x"],
      ["PUSH", 99],
      ["MAKE_DICT", 1],
      ["MAKE_DICT", 1],
      ["ADD"],
      ["HALT"]
    ])

    const result = await run(bytecode)
    expect(result.type).toBe('dict')
    if (result.type === 'dict') {
      expect(result.value.size).toBe(2)

      // a contains an array [1, 2]
      const aValue = result.value.get('a')
      expect(aValue?.type).toBe('array')
      if (aValue?.type === 'array') {
        expect(aValue.value.length).toBe(2)
        expect(aValue.value[0]).toEqual({ type: 'number', value: 1 })
        expect(aValue.value[1]).toEqual({ type: 'number', value: 2 })
      }

      // b contains a nested dict {x: 99}
      const bValue = result.value.get('b')
      expect(bValue?.type).toBe('dict')
      if (bValue?.type === 'dict') {
        expect(bValue.value.size).toBe(1)
        expect(bValue.value.get('x')).toEqual({ type: 'number', value: 99 })
      }
    }
  })

  test("cannot add boolean + boolean", async () => {
    const bytecode = toBytecode([
      ["PUSH", true],
      ["PUSH", false],
      ["ADD"],
      ["HALT"]
    ])

    await expect(run(bytecode)).rejects.toThrow('ADD: Cannot add boolean and boolean')
  })

  test("cannot add null + number", async () => {
    const bytecode = toBytecode([
      ["PUSH", null],
      ["PUSH", 5],
      ["ADD"],
      ["HALT"]
    ])

    await expect(run(bytecode)).rejects.toThrow('ADD: Cannot add null and number')
  })

  test("cannot add array + dict", async () => {
    const bytecode = toBytecode([
      ["PUSH", 1],
      ["MAKE_ARRAY", 1],
      ["MAKE_DICT", 0],
      ["ADD"],
      ["HALT"]
    ])

    await expect(run(bytecode)).rejects.toThrow('ADD: Cannot add array and dict')
  })

  test("cannot add array + number", async () => {
    const bytecode = toBytecode([
      ["PUSH", 1],
      ["MAKE_ARRAY", 1],
      ["PUSH", 5],
      ["ADD"],
      ["HALT"]
    ])

    await expect(run(bytecode)).rejects.toThrow('ADD: Cannot add array and number')
  })

  test("cannot add dict + number", async () => {
    const bytecode = toBytecode([
      ["MAKE_DICT", 0],
      ["PUSH", 5],
      ["ADD"],
      ["HALT"]
    ])

    await expect(run(bytecode)).rejects.toThrow('ADD: Cannot add dict and number')
  })

  test("cannot add function + number", async () => {
    const bytecode = toBytecode([
      ["MAKE_FUNCTION", [], ".body"],
      ["PUSH", 5],
      ["ADD"],
      ["HALT"],
      [".body:"],
      ["RETURN"]
    ])

    await expect(run(bytecode)).rejects.toThrow('ADD: Cannot add function and number')
  })

  test("cannot add boolean + null", async () => {
    const bytecode = toBytecode([
      ["PUSH", true],
      ["PUSH", null],
      ["ADD"],
      ["HALT"]
    ])

    await expect(run(bytecode)).rejects.toThrow('ADD: Cannot add boolean and null')
  })
})

describe("SUB", () => {
  test("subtract two numbers", async () => {
    const str = `
    PUSH 5
    PUSH 2
    SUB
  `
    expect(await run(toBytecode(str))).toEqual({ type: 'number', value: 3 })
  })
})

describe("MUL", () => {
  test("multiply two numbers", async () => {
    const str = `
    PUSH 5
    PUSH 2
    MUL
  `
    expect(await run(toBytecode(str))).toEqual({ type: 'number', value: 10 })
  })
})

describe("DIV", () => {
  test("divide two numbers", async () => {
    const str = `
    PUSH 10
    PUSH 2
    DIV
  `
    expect(await run(toBytecode(str))).toEqual({ type: 'number', value: 5 })

    const str2 = `
    PUSH 10
    PUSH 0
    DIV
  `
    expect(await run(toBytecode(str2))).toEqual({ type: 'number', value: Infinity })
  })
})

describe("MOD", () => {
  test("modulo two numbers", async () => {
    const str = `
    PUSH 17
    PUSH 5
    MOD
  `
    expect(await run(toBytecode(str))).toEqual({ type: 'number', value: 2 })
  })
})

describe("PUSH", () => {
  test("pushes value onto stack", async () => {
    const str = `
    PUSH 42
  `
    expect(await run(toBytecode(str))).toEqual({ type: 'number', value: 42 })
  })
})

describe("POP", () => {
  test("removes top value", async () => {
    const str = `
    PUSH 10
    PUSH 20
    POP
  `
    expect(await run(toBytecode(str))).toEqual({ type: 'number', value: 10 })
  })
})

describe("DUP", () => {
  test("duplicates top value", async () => {
    const str = `
    PUSH 5
    DUP
    ADD
  `
    expect(await run(toBytecode(str))).toEqual({ type: 'number', value: 10 })
  })
})

describe("SWAP", () => {
  test("swaps two numbers", async () => {
    const str = `
    PUSH 10
    PUSH 20
    SWAP
  `
    expect(await run(toBytecode(str))).toEqual({ type: 'number', value: 10 })
  })

  test("swap and use in subtraction", async () => {
    const str = `
    PUSH 5
    PUSH 10
    SWAP
    SUB
  `
    expect(await run(toBytecode(str))).toEqual({ type: 'number', value: 5 })
  })

  test("swap different types", async () => {
    const str = `
    PUSH "hello"
    PUSH 42
    SWAP
  `
    expect(await run(toBytecode(str))).toEqual({ type: 'string', value: 'hello' })
  })
})

describe("EQ", () => {
  test("equality comparison", async () => {
    const str = `
    PUSH 5
    PUSH 5
    EQ
  `
    expect(await run(toBytecode(str))).toEqual({ type: 'boolean', value: true })

    const str2 = `
    PUSH 5
    PUSH 10
    EQ
  `
    expect(await run(toBytecode(str2))).toEqual({ type: 'boolean', value: false })
  })

  test('equality with regexes', async () => {
    const str = `
    PUSH /cool/i
    PUSH /cool/i
    EQ
  `
    expect(await run(toBytecode(str))).toEqual({ type: 'boolean', value: true })

    const str2 = `
    PUSH /cool/
    PUSH /cool/i
    EQ
  `
    expect(await run(toBytecode(str2))).toEqual({ type: 'boolean', value: false })

    const str3 = `
    PUSH /not-cool/
    PUSH /cool/
    EQ
  `
    expect(await run(toBytecode(str3))).toEqual({ type: 'boolean', value: false })
  })
})

describe("NEQ", () => {
  test("not equal comparison", async () => {
    const str = `
    PUSH 5
    PUSH 10
    NEQ
  `
    expect(await run(toBytecode(str))).toEqual({ type: 'boolean', value: true })
  })
})

describe("LT", () => {
  test("less than", async () => {
    const str = `
    PUSH 5
    PUSH 10
    LT
  `
    expect(await run(toBytecode(str))).toEqual({ type: 'boolean', value: true })
  })
})

describe("GT", () => {
  test("greater than", async () => {
    const str = `
    PUSH 10
    PUSH 5
    GT
  `
    expect(await run(toBytecode(str))).toEqual({ type: 'boolean', value: true })
  })
})

describe("LTE", () => {
  test("less than or equal", async () => {
    // equal case
    const str = `
    PUSH 5
    PUSH 5
    LTE
  `
    expect(await run(toBytecode(str))).toEqual({ type: 'boolean', value: true })

    // less than case
    const str2 = `
    PUSH 3
    PUSH 5
    LTE
  `
    expect(await run(toBytecode(str2))).toEqual({ type: 'boolean', value: true })

    // greater than case (false)
    const str3 = `
    PUSH 10
    PUSH 5
    LTE
  `
    expect(await run(toBytecode(str3))).toEqual({ type: 'boolean', value: false })
  })
})

describe("GTE", () => {
  test("greater than or equal", async () => {
    // equal case
    const str = `
    PUSH 5
    PUSH 5
    GTE
  `
    expect(await run(toBytecode(str))).toEqual({ type: 'boolean', value: true })

    // greater than case
    const str2 = `
    PUSH 10
    PUSH 5
    GTE
  `
    expect(await run(toBytecode(str2))).toEqual({ type: 'boolean', value: true })

    // less than case (false)
    const str3 = `
    PUSH 3
    PUSH 5
    GTE
  `
    expect(await run(toBytecode(str3))).toEqual({ type: 'boolean', value: false })
  })
})

describe("Logical patterns", () => {
  test("AND pattern - short circuits when false", async () => {
    // false && <anything> should short-circuit and return false
    const str = `
    PUSH 1
    PUSH 0
    EQ
    DUP
    JUMP_IF_FALSE .end
    POP
    PUSH 999
    .end:
  `
    const result = await run(toBytecode(str))
    expect(result.type).toBe('boolean')
    if (result.type === 'boolean') {
      expect(result.value).toBe(false)
    }
  })

  test("AND pattern - evaluates both when true", async () => {
    const str = `
    PUSH 1
    DUP
    JUMP_IF_FALSE .end
    POP
    PUSH 2
    .end:
  `
    expect(await run(toBytecode(str))).toEqual({ type: 'number', value: 2 })
  })

  test("OR pattern - short circuits when true", async () => {
    const str = `
    PUSH 1
    DUP
    JUMP_IF_TRUE .end
    POP
    PUSH 2
    .end:
  `
    expect(await run(toBytecode(str))).toEqual({ type: 'number', value: 1 })
  })

  test("OR pattern - evaluates second when false", async () => {
    const str = `
    PUSH 1
    PUSH 0
    EQ
    DUP
    JUMP_IF_TRUE .end
    POP
    PUSH 2
    .end:
  `
    expect(await run(toBytecode(str))).toEqual({ type: 'number', value: 2 })
  })
})

describe("NOT", () => {
  test("logical not", async () => {
    // number is truthy, so NOT returns false
    const str = `
    PUSH 1
    NOT
  `
    expect(await run(toBytecode(str))).toEqual({ type: 'boolean', value: false })

    // 0 is truthy in this language, so NOT returns false
    const str2 = `
    PUSH 0
    NOT
  `
    expect(await run(toBytecode(str2))).toEqual({ type: 'boolean', value: false })

    // boolean false is falsy, so NOT returns true
    const str3 = `
    PUSH 1
    PUSH 0
    EQ
    NOT
  `
    expect(await run(toBytecode(str3))).toEqual({ type: 'boolean', value: true })
  })
})

describe("Truthiness", () => {
  test("only null and false are falsy", async () => {
    // 0 is truthy (unlike JS)
    const str1 = `
    PUSH 0
    JUMP_IF_FALSE .end
    PUSH 1
    .end:
  `
    expect(await run(toBytecode(str1))).toEqual({ type: 'number', value: 1 })

    // empty string is truthy (unlike JS)
    const str2 = `
    PUSH ''
    JUMP_IF_FALSE .end
    PUSH 1
    .end:
  `
    expect(await run(toBytecode(str2))).toEqual({ type: 'number', value: 1 })

    // false is falsy
    const str3 = `
    PUSH 0
    PUSH 0
    EQ
    JUMP_IF_FALSE .end
    PUSH 999
    .end:
  `
    expect(await run(toBytecode(str3))).toEqual({ type: 'number', value: 999 })
  })
})

describe("HALT", () => {
  test("stops execution", async () => {
    const str = `
    PUSH 42
    HALT
    PUSH 100
  `
    expect(await run(toBytecode(str))).toEqual({ type: 'number', value: 42 })
  })
})

describe("LOAD / STORE", () => {
  test("variables", async () => {
    const str = `
    PUSH 42
    STORE x
    PUSH 21
    LOAD x
  `
    expect(await run(toBytecode(str))).toEqual({ type: 'number', value: 42 })
  })

  test("multiple variables", async () => {
    const str = `
    PUSH 10
    STORE a
    PUSH 20
    STORE b
    PUSH 44
    LOAD a
    LOAD b
    ADD
  `
    expect(await run(toBytecode(str))).toEqual({ type: 'number', value: 30 })
  })
})

describe("TRY_LOAD", () => {
  test("variable found", async () => {
    const str = `
    PUSH 100
    STORE count
    TRY_LOAD count
    `
    expect(await run(toBytecode(str))).toEqual({ type: 'number', value: 100 })

    const str2 = `
    PUSH 'Bobby'
    STORE name
    TRY_LOAD name
    `
    expect(await run(toBytecode(str2))).toEqual({ type: 'string', value: 'Bobby' })
  })

  test("variable missing", async () => {
    const str = `
    PUSH 100
    STORE count
    TRY_LOAD count1
    `
    expect(await run(toBytecode(str))).toEqual({ type: 'string', value: 'count1' })

    const str2 = `
    PUSH 'Bobby'
    STORE name
    TRY_LOAD full-name
    `
    expect(await run(toBytecode(str2))).toEqual({ type: 'string', value: 'full-name' })
  })

  test("with different value types", async () => {
    // Array
    const str1 = `
    PUSH 1
    PUSH 2
    PUSH 3
    MAKE_ARRAY #3
    STORE arr
    TRY_LOAD arr
    `
    const result1 = await run(toBytecode(str1))
    expect(result1.type).toBe('array')

    // Dict
    const str2 = `
    PUSH 'key'
    PUSH 'value'
    MAKE_DICT #1
    STORE dict
    TRY_LOAD dict
    `
    const result2 = await run(toBytecode(str2))
    expect(result2.type).toBe('dict')

    // Boolean
    const str3 = `
    PUSH true
    STORE flag
    TRY_LOAD flag
    `
    expect(await run(toBytecode(str3))).toEqual({ type: 'boolean', value: true })

    // Null
    const str4 = `
    PUSH null
    STORE empty
    TRY_LOAD empty
    `
    expect(await run(toBytecode(str4))).toEqual({ type: 'null', value: null })
  })

  test("in nested scope", async () => {
    // Function should be able to TRY_LOAD variable from parent scope
    const str = `
    PUSH 42
    STORE outer
    MAKE_FUNCTION () .fn
    PUSH 0
    PUSH 0
    CALL
    HALT
    .fn:
    TRY_LOAD outer
    RETURN
    `
    expect(await run(toBytecode(str))).toEqual({ type: 'number', value: 42 })
  })

  test("missing variable in nested scope returns name", async () => {
    // If variable doesn't exist in any scope, should return name as string
    const str = `
    PUSH 42
    STORE outer
    MAKE_FUNCTION () .fn
    PUSH 0
    PUSH 0
    CALL
    HALT
    .fn:
    TRY_LOAD inner
    RETURN
    `
    expect(await run(toBytecode(str))).toEqual({ type: 'string', value: 'inner' })
  })

  test("used for conditional variable existence check", async () => {
    // Pattern: use TRY_LOAD to check if variable exists and get its value or name
    const str = `
    PUSH 100
    STORE count
    TRY_LOAD count
    PUSH 'count'
    EQ
    `
    // Variable exists, so TRY_LOAD returns 100, which != 'count'
    expect(await run(toBytecode(str))).toEqual({ type: 'boolean', value: false })

    const str2 = `
    PUSH 100
    STORE count
    TRY_LOAD missing
    PUSH 'missing'
    EQ
    `
    // Variable missing, so TRY_LOAD returns 'missing', which == 'missing'
    expect(await run(toBytecode(str2))).toEqual({ type: 'boolean', value: true })
  })

  test("with function value", async () => {
    const str = `
    MAKE_FUNCTION () .fn
    STORE myFunc
    JUMP .skip
    .fn:
    PUSH 99
    RETURN
    .skip:
    TRY_LOAD myFunc
    `
    const result = await run(toBytecode(str))
    expect(result.type).toBe('function')
  })
})

describe("JUMP", () => {
  test("relative jump forward", async () => {
    const str = `
    PUSH 1
    JUMP .skip
    PUSH 100
    .skip:
    PUSH 2
  `
    expect(await run(toBytecode(str))).toEqual({ type: 'number', value: 2 })
  })

  test("forward jump skips instructions", async () => {
    // Use forward jump to skip, demonstrating relative addressing
    const str = `
    PUSH 100
    JUMP .end
    PUSH 200
    PUSH 300
    .end:
    PUSH 400
  `
    expect(await run(toBytecode(str))).toEqual({ type: 'number', value: 400 })
  })

  test("backward - simple loop", async () => {
    // Very simple: counter starts at 0, loops 3 times incrementing
    // On 3rd iteration (counter==3), exits and returns counter
    const bytecode = toBytecode(`
      PUSH 0
      STORE counter
      .loop:
      LOAD counter
      PUSH 3
      EQ
      JUMP_IF_FALSE .body
      LOAD counter
      HALT
      .body:
      LOAD counter
      PUSH 1
      ADD
      STORE counter
      JUMP .loop
    `)

    const result = await run(bytecode)
    expect(result).toEqual({ type: 'number', value: 3 })
  })
})

describe("JUMP_IF_FALSE", () => {
  test("conditional jump when false", async () => {
    const str = `
    PUSH 1
    PUSH 0
    EQ
    JUMP_IF_FALSE .skip
    PUSH 100
    .skip:
    PUSH 42
  `
    expect(await run(toBytecode(str))).toEqual({ type: 'number', value: 42 })
  })

  test("no jump when true", async () => {
    const str = `
    PUSH 1
    JUMP_IF_FALSE .skip
    PUSH 100
    .skip:
  `
    expect(await run(toBytecode(str))).toEqual({ type: 'number', value: 100 })
  })
})

describe("JUMP_IF_TRUE", () => {
  test("conditional jump when true", async () => {
    const str = `
    PUSH 1
    JUMP_IF_TRUE .skip
    PUSH 100
    .skip:
    PUSH 42
  `
    expect(await run(toBytecode(str))).toEqual({ type: 'number', value: 42 })
  })
})

describe("MAKE_ARRAY", () => {
  test("creates array", async () => {
    const str = `
    PUSH 10
    PUSH 20
    PUSH 30
    MAKE_ARRAY #3
  `
    const result = await run(toBytecode(str))
    expect(result.type).toBe('array')
    if (result.type === 'array') {
      expect(result.value).toHaveLength(3)
      expect(result.value[0]).toEqual({ type: 'number', value: 10 })
      expect(result.value[1]).toEqual({ type: 'number', value: 20 })
      expect(result.value[2]).toEqual({ type: 'number', value: 30 })
    }
  })
})

describe("ARRAY_GET", () => {
  test("gets element", async () => {
    const str = `
    PUSH 10
    PUSH 20
    PUSH 30
    MAKE_ARRAY #3
    PUSH 1
    ARRAY_GET
  `
    expect(await run(toBytecode(str))).toEqual({ type: 'number', value: 20 })
  })
})

describe("ARRAY_SET", () => {
  test("sets element", async () => {
    const str = `
    PUSH 10
    PUSH 20
    PUSH 30
    MAKE_ARRAY #3
    DUP
    PUSH 1
    PUSH 99
    ARRAY_SET
    PUSH 1
    ARRAY_GET
  `
    expect(await run(toBytecode(str))).toEqual({ type: 'number', value: 99 })
  })
})

describe("ARRAY_PUSH", () => {
  test("appends to array", async () => {
    const str = `
    PUSH 10
    PUSH 20
    MAKE_ARRAY #2
    DUP
    PUSH 30
    ARRAY_PUSH
    ARRAY_LEN
  `
    expect(await run(toBytecode(str))).toEqual({ type: 'number', value: 3 })
  })

  test("mutates original array", async () => {
    const str = `
    PUSH 10
    PUSH 20
    MAKE_ARRAY #2
    DUP
    PUSH 30
    ARRAY_PUSH
    PUSH 2
    ARRAY_GET
  `
    expect(await run(toBytecode(str))).toEqual({ type: 'number', value: 30 })
  })
})

describe("ARRAY_LEN", () => {
  test("gets length", async () => {
    const str = `
    PUSH 10
    PUSH 20
    PUSH 30
    MAKE_ARRAY #3
    ARRAY_LEN
  `
    expect(await run(toBytecode(str))).toEqual({ type: 'number', value: 3 })
  })
})

describe("MAKE_DICT", () => {
  test("creates dict", async () => {
    const str = `
    PUSH 'name'
    PUSH 'Alice'
    PUSH 'age'
    PUSH 30
    MAKE_DICT #2
  `
    const result = await run(toBytecode(str))
    expect(result.type).toBe('dict')
    if (result.type === 'dict') {
      expect(result.value.size).toBe(2)
      expect(result.value.get('name')).toEqual({ type: 'string', value: 'Alice' })
      expect(result.value.get('age')).toEqual({ type: 'number', value: 30 })
    }
  })
})

describe("DICT_GET", () => {
  test("gets value", async () => {
    const str = `
    PUSH 'name'
    PUSH 'Bob'
    MAKE_DICT #1
    PUSH 'name'
    DICT_GET
  `
    expect(await run(toBytecode(str))).toEqual({ type: 'string', value: 'Bob' })
  })
})

describe("DICT_SET", () => {
  test("sets value", async () => {
    const str = `
    MAKE_DICT #0
    DUP
    PUSH 'key'
    PUSH 'value'
    DICT_SET
    PUSH 'key'
    DICT_GET
  `
    expect(await run(toBytecode(str))).toEqual({ type: 'string', value: 'value' })
  })
})

describe("DICT_HAS", () => {
  test("checks key exists", async () => {
    const str = `
    PUSH 'key'
    PUSH 'value'
    MAKE_DICT #1
    PUSH 'key'
    DICT_HAS
  `
    expect(await run(toBytecode(str))).toEqual({ type: 'boolean', value: true })
  })

  test("checks key missing", async () => {
    const str = `
    MAKE_DICT #0
    PUSH 'missing'
    DICT_HAS
  `
    expect(await run(toBytecode(str))).toEqual({ type: 'boolean', value: false })
  })
})

describe("DOT_GET", () => {
  test("gets an ARRAY index", async () => {
    const bytecode = toBytecode(`
      PUSH 100
      PUSH 200
      PUSH 300
      PUSH 400
      MAKE_ARRAY #4
      PUSH 2
      DOT_GET
`)

    expect(await run(bytecode)).toEqual({ type: 'number', value: 300 })
  })

  test("gets a DICT value", async () => {
    const bytecode = toBytecode(`
      PUSH 'name'
      PUSH 'Bob'
      PUSH 'age'
      PUSH 106
      MAKE_DICT #2
      PUSH 'name'
      DOT_GET
`)

    expect(await run(bytecode)).toEqual({ type: 'string', value: 'Bob' })
  })

  test("fails to work on NUMBER", async () => {
    const bytecode = toBytecode(`
      PUSH 500
      PUSH 0
      DOT_GET
      `)

    try {
      await run(bytecode)
      expect(true).toBe(false)  // Should not reach here
    } catch (e: any) {
      expect(e.message).toContain('DOT_GET: number not supported')
    }
  })

  test("fails to work on STRING", async () => {
    const bytecode = toBytecode(`
      PUSH 'ShrimpVM?'
      PUSH 1
      DOT_GET
      `)

    try {
      await run(bytecode)
      expect(true).toBe(false)  // Should not reach here
    } catch (e: any) {
      expect(e.message).toContain('DOT_GET: string not supported')
    }
  })

  test("array - returns null for out of bounds", async () => {
    const bytecode = toBytecode(`
      PUSH 10
      PUSH 20
      MAKE_ARRAY #2
      PUSH 5
      DOT_GET
    `)

    expect(await run(bytecode)).toEqual({ type: 'null', value: null })
  })

  test("array - negative index", async () => {
    const bytecode = toBytecode(`
      PUSH 10
      PUSH 20
      PUSH 30
      MAKE_ARRAY #3
      PUSH -1
      DOT_GET
    `)

    expect(await run(bytecode)).toEqual({ type: 'null', value: null })
  })

  test("array - first and last element", async () => {
    const bytecode = toBytecode(`
      PUSH 100
      PUSH 200
      PUSH 300
      MAKE_ARRAY #3
      DUP
      PUSH 0
      DOT_GET
      STORE first
      PUSH 2
      DOT_GET
      STORE last
      LOAD first
      LOAD last
      ADD
    `)

    expect(await run(bytecode)).toEqual({ type: 'number', value: 400 })
  })

  test("dict - returns null for missing key", async () => {
    const bytecode = toBytecode(`
      PUSH 'name'
      PUSH 'Alice'
      MAKE_DICT #1
      PUSH 'age'
      DOT_GET
    `)

    expect(await run(bytecode)).toEqual({ type: 'null', value: null })
  })

  test("dict - with numeric key", async () => {
    const bytecode = toBytecode(`
      PUSH '123'
      PUSH 'value'
      MAKE_DICT #1
      PUSH 123
      DOT_GET
    `)

    expect(await run(bytecode)).toEqual({ type: 'string', value: 'value' })
  })

  test("array - with string value", async () => {
    const bytecode = toBytecode(`
      PUSH 'foo'
      PUSH 'bar'
      PUSH 'baz'
      MAKE_ARRAY #3
      PUSH 1
      DOT_GET
    `)

    expect(await run(bytecode)).toEqual({ type: 'string', value: 'bar' })
  })

  test("array - with boolean values", async () => {
    const bytecode = toBytecode(`
      PUSH true
      PUSH false
      PUSH true
      MAKE_ARRAY #3
      PUSH 1
      DOT_GET
    `)

    expect(await run(bytecode)).toEqual({ type: 'boolean', value: false })
  })

  test("dict - with boolean value", async () => {
    const bytecode = toBytecode(`
      PUSH 'active'
      PUSH true
      PUSH 'visible'
      PUSH false
      MAKE_DICT #2
      PUSH 'active'
      DOT_GET
    `)

    expect(await run(bytecode)).toEqual({ type: 'boolean', value: true })
  })

  test("array - nested arrays", async () => {
    const bytecode = toBytecode(`
      PUSH 1
      PUSH 2
      MAKE_ARRAY #2
      PUSH 3
      PUSH 4
      MAKE_ARRAY #2
      MAKE_ARRAY #2
      PUSH 1
      DOT_GET
    `)

    const result = await run(bytecode)
    expect(result.type).toBe('array')
    if (result.type === 'array') {
      expect(result.value).toHaveLength(2)
      expect(result.value[0]).toEqual({ type: 'number', value: 3 })
      expect(result.value[1]).toEqual({ type: 'number', value: 4 })
    }
  })

  test("dict - nested dicts", async () => {
    const bytecode = toBytecode(`
      PUSH 'user'
      PUSH 'name'
      PUSH 'Alice'
      MAKE_DICT #1
      MAKE_DICT #1
      PUSH 'user'
      DOT_GET
    `)

    const result = await run(bytecode)
    expect(result.type).toBe('dict')
    if (result.type === 'dict') {
      expect(result.value.get('name')).toEqual({ type: 'string', value: 'Alice' })
    }
  })

  test("array format", async () => {
    const bytecode = toBytecode([
      ["PUSH", "apple"],
      ["PUSH", "banana"],
      ["PUSH", "cherry"],
      ["MAKE_ARRAY", 3],
      ["PUSH", 1],
      ["DOT_GET"],
      ["HALT"]
    ])

    expect(await run(bytecode)).toEqual({ type: 'string', value: 'banana' })
  })

  test("with variables - array", async () => {
    const bytecode = toBytecode(`
      PUSH 10
      PUSH 20
      PUSH 30
      MAKE_ARRAY #3
      STORE arr
      PUSH 1
      STORE idx
      LOAD arr
      LOAD idx
      DOT_GET
    `)

    expect(await run(bytecode)).toEqual({ type: 'number', value: 20 })
  })

  test("with variables - dict", async () => {
    const bytecode = toBytecode(`
      PUSH 'x'
      PUSH 100
      PUSH 'y'
      PUSH 200
      MAKE_DICT #2
      STORE point
      PUSH 'y'
      STORE key
      LOAD point
      LOAD key
      DOT_GET
    `)

    expect(await run(bytecode)).toEqual({ type: 'number', value: 200 })
  })

  test("with expression as index", async () => {
    const bytecode = toBytecode(`
      PUSH 10
      PUSH 20
      PUSH 30
      PUSH 40
      MAKE_ARRAY #4
      PUSH 1
      PUSH 2
      ADD
      DOT_GET
    `)

    expect(await run(bytecode)).toEqual({ type: 'number', value: 40 })
  })

  test("chained access - array of dicts", async () => {
    const bytecode = toBytecode(`
      PUSH 'name'
      PUSH 'Alice'
      MAKE_DICT #1
      PUSH 'name'
      PUSH 'Bob'
      MAKE_DICT #1
      MAKE_ARRAY #2
      PUSH 1
      DOT_GET
      PUSH 'name'
      DOT_GET
    `)

    expect(await run(bytecode)).toEqual({ type: 'string', value: 'Bob' })
  })

  test("chained access - dict of arrays", async () => {
    const bytecode = toBytecode(`
      PUSH 'nums'
      PUSH 1
      PUSH 2
      PUSH 3
      MAKE_ARRAY #3
      MAKE_DICT #1
      PUSH 'nums'
      DOT_GET
      PUSH 1
      DOT_GET
    `)

    expect(await run(bytecode)).toEqual({ type: 'number', value: 2 })
  })

  test("with null value in array", async () => {
    const bytecode = toBytecode(`
      PUSH 10
      PUSH null
      PUSH 30
      MAKE_ARRAY #3
      PUSH 1
      DOT_GET
    `)

    expect(await run(bytecode)).toEqual({ type: 'null', value: null })
  })

  test("with null value in dict", async () => {
    const bytecode = toBytecode(`
      PUSH 'name'
      PUSH 'Alice'
      PUSH 'middle'
      PUSH null
      MAKE_DICT #2
      PUSH 'middle'
      DOT_GET
    `)

    expect(await run(bytecode)).toEqual({ type: 'null', value: null })
  })

  test("array with regex values", async () => {
    const bytecode = toBytecode(`
      PUSH /foo/
      PUSH /bar/i
      PUSH /baz/g
      MAKE_ARRAY #3
      PUSH 1
      DOT_GET
    `)

    const result = await run(bytecode)
    expect(result.type).toBe('regex')
    if (result.type === 'regex') {
      expect(result.value.source).toBe('bar')
      expect(result.value.ignoreCase).toBe(true)
    }
  })

  test("dict with regex values", async () => {
    const bytecode = toBytecode(`
      PUSH 'email'
      PUSH /^[a-z@.]+$/i
      PUSH 'url'
      PUSH /^https?:\\/\\//
      MAKE_DICT #2
      PUSH 'email'
      DOT_GET
    `)

    const result = await run(bytecode)
    expect(result.type).toBe('regex')
    if (result.type === 'regex') {
      expect(result.value.source).toBe('^[a-z@.]+$')
      expect(result.value.ignoreCase).toBe(true)
    }
  })

  test("dict - key coercion from number", async () => {
    const bytecode = toBytecode(`
      PUSH '0'
      PUSH 'zero'
      PUSH '1'
      PUSH 'one'
      MAKE_DICT #2
      PUSH 0
      DOT_GET
    `)

    expect(await run(bytecode)).toEqual({ type: 'string', value: 'zero' })
  })

  test("fails on boolean", async () => {
    const bytecode = toBytecode(`
      PUSH true
      PUSH 0
      DOT_GET
    `)

    try {
      await run(bytecode)
      expect(true).toBe(false)
    } catch (e: any) {
      expect(e.message).toContain('DOT_GET: boolean not supported')
    }
  })

  test("fails on null", async () => {
    const bytecode = toBytecode(`
      PUSH null
      PUSH 0
      DOT_GET
    `)

    try {
      await run(bytecode)
      expect(true).toBe(false)
    } catch (e: any) {
      expect(e.message).toContain('DOT_GET: null not supported')
    }
  })

  test("fails on regex", async () => {
    const bytecode = toBytecode(`
      PUSH /test/
      PUSH 0
      DOT_GET
    `)

    try {
      await run(bytecode)
      expect(true).toBe(false)
    } catch (e: any) {
      expect(e.message).toContain('DOT_GET: regex not supported')
    }
  })

  test("empty array access", async () => {
    const bytecode = toBytecode(`
      MAKE_ARRAY #0
      PUSH 0
      DOT_GET
    `)

    expect(await run(bytecode)).toEqual({ type: 'null', value: null })
  })

  test("empty dict access", async () => {
    const bytecode = toBytecode(`
      MAKE_DICT #0
      PUSH 'key'
      DOT_GET
    `)

    expect(await run(bytecode)).toEqual({ type: 'null', value: null })
  })
})

describe("STR_CONCAT", () => {
  test("concats together strings", async () => {
    const str = `
    PUSH "Hi "
    PUSH "friend"
    PUSH "!"
    STR_CONCAT #3
    `

    expect(await run(toBytecode(str))).toEqual({ type: 'string', value: "Hi friend!" })

    const str2 = `
    PUSH "Holy smokes!"
    PUSH "It's "
    PUSH "alive!"
    STR_CONCAT #2
    `

    expect(await run(toBytecode(str2))).toEqual({ type: 'string', value: "It's alive!" })


    const str3 = `
    PUSH 1
    PUSH " + "
    PUSH 1
    PUSH " = "
    PUSH 1
    PUSH 1
    ADD
    STR_CONCAT #5
    `

    expect(await run(toBytecode(str3))).toEqual({ type: 'string', value: "1 + 1 = 2" })
  })

  test("empty concat (count=0)", async () => {
    const str = `
    PUSH "leftover"
    STR_CONCAT #0
    `
    expect(await run(toBytecode(str))).toEqual({ type: 'string', value: "" })
  })

  test("single string", async () => {
    const str = `
    PUSH "hello"
    STR_CONCAT #1
    `
    expect(await run(toBytecode(str))).toEqual({ type: 'string', value: "hello" })
  })

  test("converts numbers to strings", async () => {
    const str = `
    PUSH 42
    PUSH 100
    PUSH 7
    STR_CONCAT #3
    `
    expect(await run(toBytecode(str))).toEqual({ type: 'string', value: "421007" })
  })

  test("converts booleans to strings", async () => {
    const str = `
    PUSH "Result: "
    PUSH true
    STR_CONCAT #2
    `
    expect(await run(toBytecode(str))).toEqual({ type: 'string', value: "Result: true" })

    const str2 = `
    PUSH false
    PUSH " is false"
    STR_CONCAT #2
    `
    expect(await run(toBytecode(str2))).toEqual({ type: 'string', value: "false is false" })
  })

  test("converts null to strings", async () => {
    const str = `
    PUSH "Value: "
    PUSH null
    STR_CONCAT #2
    `
    expect(await run(toBytecode(str))).toEqual({ type: 'string', value: "Value: null" })
  })

  test("mixed types", async () => {
    const str = `
    PUSH "Count: "
    PUSH 42
    PUSH ", Active: "
    PUSH true
    PUSH ", Total: "
    PUSH null
    STR_CONCAT #6
    `
    expect(await run(toBytecode(str))).toEqual({ type: 'string', value: "Count: 42, Active: true, Total: null" })
  })

  test("array format", async () => {
    const bytecode = toBytecode([
      ["PUSH", "Hello"],
      ["PUSH", " "],
      ["PUSH", "World"],
      ["STR_CONCAT", 3],
      ["HALT"]
    ])

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

  test("with variables", async () => {
    const str = `
    PUSH "Alice"
    STORE name
    PUSH "Hello, "
    LOAD name
    PUSH "!"
    STR_CONCAT #3
    `
    expect(await run(toBytecode(str))).toEqual({ type: 'string', value: "Hello, Alice!" })
  })

  test("composable (multiple concatenations)", async () => {
    const str = `
    PUSH "Hello"
    PUSH " "
    PUSH "World"
    STR_CONCAT #3
    PUSH "!"
    STR_CONCAT #2
    `
    expect(await run(toBytecode(str))).toEqual({ type: 'string', value: "Hello World!" })
  })

  test("with emoji and unicode", async () => {
    const str = `
    PUSH "Hello "
    PUSH "🌍"
    PUSH "!"
    STR_CONCAT #3
    `
    expect(await run(toBytecode(str))).toEqual({ type: 'string', value: "Hello 🌍!" })

    const str2 = `
    PUSH "こんにちは"
    PUSH "世界"
    STR_CONCAT #2
    `
    expect(await run(toBytecode(str2))).toEqual({ type: 'string', value: "こんにちは世界" })
  })

  test("with expressions", async () => {
    const str = `
    PUSH "Result: "
    PUSH 10
    PUSH 5
    ADD
    STR_CONCAT #2
    `
    expect(await run(toBytecode(str))).toEqual({ type: 'string', value: "Result: 15" })
  })

  test("large concat", async () => {
    const str = `
    PUSH "a"
    PUSH "b"
    PUSH "c"
    PUSH "d"
    PUSH "e"
    PUSH "f"
    PUSH "g"
    PUSH "h"
    PUSH "i"
    PUSH "j"
    STR_CONCAT #10
    `
    expect(await run(toBytecode(str))).toEqual({ type: 'string', value: "abcdefghij" })
  })
})

describe("BREAK", () => {
  test("throws error when no break target", async () => {
    // BREAK requires a break target frame on the call stack
    // A single function call has no previous frame to mark as break target
    const bytecode = toBytecode(`
      MAKE_FUNCTION () .fn
      PUSH 0
      PUSH 0
      CALL
      HALT
      .fn:
      BREAK
    `)

    try {
      await run(bytecode)
      expect(true).toBe(false)  // Should not reach here
    } catch (e: any) {
      expect(e.message).toContain('no break target found')
    }
  })

  test("exits from nested function call", async () => {
    // BREAK unwinds to the break target (the outer function's frame)
    // Main calls outer, outer calls inner, inner BREAKs back to outer's caller (main)
    const bytecode = toBytecode(`
      MAKE_FUNCTION () .outer
      PUSH 0
      PUSH 0
      CALL
      PUSH 42
      HALT
      .outer:
      MAKE_FUNCTION () .inner
      PUSH 0
      PUSH 0
      CALL
      PUSH 99
      RETURN
      .inner:
      BREAK
    `)

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