import { describe } from 'bun:test'
import { expect, test } from 'bun:test'

describe('exception handling', () => {
  test('try with catch - no error thrown', () => {
    expect(`
      try:
        42
      catch err:
        99
      end
    `).toEvaluateTo(42)
  })

  test('try with catch - error thrown', () => {
    expect(`
      try:
        throw 'something went wrong'
        99
      catch err:
        err
      end
    `).toEvaluateTo('something went wrong')
  })

  test('try with catch - catch variable binding', () => {
    expect(`
      try:
        throw 100
      catch my-error:
        my-error + 50
      end
    `).toEvaluateTo(150)
  })

  test('try with finally - no error', () => {
    expect(`
      x = 0
      result = try:
        x = 10
        42
      finally:
        x = x + 5
      end
      x
    `).toEvaluateTo(15)
  })

  test('try with finally - return value from try', () => {
    expect(`
      x = 0
      result = try:
        x = 10
        42
      finally:
        x = x + 5
        999
      end
      result
    `).toEvaluateTo(42)
  })

  test('try with catch and finally - no error', () => {
    expect(`
      x = 0
      try:
        x = 10
        42
      catch err:
        x = 999
        0
      finally:
        x = x + 5
      end
      x
    `).toEvaluateTo(15)
  })

  test('try with catch and finally - error thrown', () => {
    expect(`
      x = 0
      result = try:
        x = 10
        throw 'error'
        99
      catch err:
        x = 20
        err
      finally:
        x = x + 5
      end
      x
    `).toEvaluateTo(25)
  })

  test('try with catch and finally - return value from catch', () => {
    expect(`
      result = try:
        throw 'oops'
      catch err:
        'caught'
      finally:
        'finally'
      end
      result
    `).toEvaluateTo('caught')
  })

  test('throw statement with string', () => {
    expect(`
      try:
        throw 'error message'
      catch err:
        err
      end
    `).toEvaluateTo('error message')
  })

  test('throw statement with number', () => {
    expect(`
      try:
        throw 404
      catch err:
        err
      end
    `).toEvaluateTo(404)
  })

  test('throw statement with dict', () => {
    expect(`
      try:
        throw [code=500 message=failed]
      catch e:
        e
      end
    `).toEvaluateTo({ code: 500, message: 'failed' })
  })

  test('uncaught exception fails', () => {
    expect(`throw 'uncaught error'`).toFailEvaluation()
  })

  test('single-line try catch', () => {
    expect(`result = try: throw 'err' catch e: 'handled' end; result`).toEvaluateTo('handled')
  })

  test('nested try blocks - inner catches', () => {
    expect(`
      try:
        result = try:
          throw 'inner error'
        catch err:
          err
        end
        result
      catch outer:
        'outer'
      end
    `).toEvaluateTo('inner error')
  })

  test('nested try blocks - outer catches', () => {
    expect(`
      try:
        try:
          throw 'inner error'
        catch err:
          throw 'outer error'
        end
      catch outer:
        outer
      end
    `).toEvaluateTo('outer error')
  })

  test('try as expression', () => {
    expect(`
      x = try: 10 catch err: 0 end
      y = try: throw 'err' catch err: 20 end
      x + y
    `).toEvaluateTo(30)
  })
})

describe('function-level exception handling', () => {
  test('function with catch - no error', () => {
    expect(`
      read-file = do path:
        path
      catch e:
        'default'
      end

      read-file test.txt
    `).toEvaluateTo('test.txt')
  })

  test('function with catch - error thrown', () => {
    expect(`
      read-file = do path:
        throw 'file not found'
      catch e:
        'default'
      end

      read-file test.txt
    `).toEvaluateTo('default')
  })

  test('function with catch - error variable binding', () => {
    expect(`
      safe-call = do:
        throw 'operation failed'
      catch err:
        err
      end

      safe-call
    `).toEvaluateTo('operation failed')
  })

  test('function with finally - always runs', () => {
    expect(`
      counter = 0
      increment-task = do:
        result = 42
        result
      finally:
        counter = counter + 1
      end

      x = increment-task
      y = increment-task
      counter
    `).toEvaluateTo(2)
  })

  test('function with finally - return value from body', () => {
    expect(`
      get-value = do:
        100
      finally:
        999
      end

      get-value
    `).toEvaluateTo(100)
  })

  test('function with catch and finally', () => {
    expect(`
      cleanup-count = 0
      safe-op = do should-fail:
        if should-fail:
          throw 'failed'
        end
        'success'
      catch e:
        'caught'
      finally:
        cleanup-count = cleanup-count + 1
      end

      result1 = safe-op false
      result2 = safe-op true
      cleanup-count
    `).toEvaluateTo(2)
  })

  test('function with catch and finally - catch return value', () => {
    expect(`
      safe-fail = do:
        throw 'always fails'
      catch e:
        'error handled'
      finally:
        noop = 1
      end

      safe-fail
    `).toEvaluateTo('error handled')
  })

  test('function without catch/finally still works', () => {
    expect(`
      regular = do x:
        x + 10
      end

      regular 5
    `).toEvaluateTo(15)
  })

  test('nested functions with catch', () => {
    expect(`
      inner = do:
        throw 'inner error'
      catch e:
        'inner caught'
      end

      outer = do:
        inner
      catch e:
        'outer caught'
      end

      outer
    `).toEvaluateTo('inner caught')
  })
})