# Copyright (c) Microsoft Corporation.
# Licensed under the MIT License.

# Empty Collections Loop Test Suite
# Tests behavior of various loop types over empty collections
# 1. Comprehensions should evaluate to their empty versions
# 2. some..in should evaluate to false  
# 3. every should evaluate to true

cases:
  - note: existential_empty_array
    description: Existential quantification (some) on empty array should return false
    example_rego: |
      # some x in []
      # x > 0  # false - no elements to satisfy condition
    literals:
      - {}
      - 0  # comparison value
    instruction_params:
      loop_params:
        - mode: "Any"
          collection: 0
          key_reg: 4
          value_reg: 5
          body_start: 2
          loop_end: 6
          result_reg: 6
    instructions:
      - "ArrayNew { dest: 0 }"              # Create empty array in register 0
      - "LoopStart { params_index: 0 }"
      - "Load { dest: 7, literal_idx: 1 }"  # Load comparison value 0
      - "Gt { dest: 8, left: 5, right: 7 }" # Check if current value > 0
      - "AssertCondition { condition: 8 }"  # Assert the condition
      - "LoopNext { body_start: 2, loop_end: 6 }"
      - "Return { value: 6 }"               # Return false for empty collection
    want_result: false

  - note: universal_empty_array
    description: Universal quantification (every) on empty array should return true  
    example_rego: |
      # every x in []
      # x > 0  # true - vacuously true (no elements to violate condition)
    literals:
      - {}
      - 0  # comparison value
    instruction_params:
      loop_params:
        - mode: "Every"
          collection: 0
          key_reg: 4
          value_reg: 5
          result_reg: 6
          body_start: 2
          loop_end: 6
    instructions:
      - "ArrayNew { dest: 0 }"              # Create empty array in register 0
      - "LoopStart { params_index: 0 }"
      - "Load { dest: 7, literal_idx: 1 }"  # Load comparison value 0
      - "Gt { dest: 8, left: 5, right: 7 }" # Check if current value > 0
      - "AssertCondition { condition: 8 }"  # Assert the condition
      - "LoopNext { body_start: 2, loop_end: 6 }"
      - "Return { value: 6 }"               # Return true for empty collection (vacuously true)
    want_result: true

  - note: array_comprehension_empty
    description: Array comprehension on empty collection should return empty array
    example_rego: |
      # [x + 1 | x = []; true]  # []
      # Transform each element by adding 1
    literals:
      - {}
      - 1  # value to add
    instruction_params:
      comprehension_begin_params:
        - mode: "Array"
          collection_reg: 1
          key_reg: 4
          value_reg: 5
          body_start: 3
          comprehension_end: 9
      loop_params:
        - mode: "ForEach"
          collection: 0
          key_reg: 4
          value_reg: 5
          result_reg: 8
          body_start: 4
          loop_end: 9
    instructions:
      - "ArrayNew { dest: 0 }"              # Create empty input array in register 0
      - "ComprehensionBegin { params_index: 0 }"  # Start array comprehension
      - "LoopStart { params_index: 0 }"     # Start loop over array elements
      - "Load { dest: 6, literal_idx: 1 }"  # Load 1 into register 6
      - "Add { dest: 7, left: 5, right: 6 }" # Add 1 to current value
      - "ComprehensionYield { value_reg: 7 }"  # Add result to comprehension
      - "LoadBool { dest: 8, value: true }" # Load true (condition always passes)
      - "AssertCondition { condition: 8 }"  # Assert true condition
      - "LoopNext { body_start: 4, loop_end: 9 }"  # Continue to next iteration or exit
      - "Return { value: 1 }"               # Return the result array (should be empty)
    want_result: []

  - note: set_comprehension_empty
    description: Set comprehension on empty collection should return empty set
    example_rego: |
      # {x + 1 | x = []; true}  # set()
      # Transform each element by adding 1 into a set
    literals:
      - {}
      - 1  # value to add
    instruction_params:
      comprehension_begin_params:
        - mode: "Set"
          collection_reg: 1
          key_reg: 4
          value_reg: 5
          body_start: 3
          comprehension_end: 9
      loop_params:
        - mode: "ForEach"
          collection: 0
          key_reg: 4
          value_reg: 5
          result_reg: 8
          body_start: 4
          loop_end: 9
    instructions:
      - "ArrayNew { dest: 0 }"              # Create empty input array in register 0
      - "ComprehensionBegin { params_index: 0 }"  # Start set comprehension
      - "LoopStart { params_index: 0 }"     # Start loop over array elements
      - "Load { dest: 6, literal_idx: 1 }"  # Load 1 into register 6
      - "Add { dest: 7, left: 5, right: 6 }" # Add 1 to current value
      - "ComprehensionYield { value_reg: 7 }"  # Add result to comprehension
      - "LoadBool { dest: 8, value: true }" # Load true (condition always passes)
      - "AssertCondition { condition: 8 }"  # Assert true condition
      - "LoopNext { body_start: 4, loop_end: 9 }"  # Continue to next iteration or exit
      - "Return { value: 1 }"               # Return the result set (should be empty)
    want_result: 
      set!: []  # Set serializes as empty array

  - note: object_comprehension_empty
    description: Object comprehension on empty collection should return empty object
    example_rego: |
      # {k: v + 1 | some k, v in {}; true}  # {}
      # Transform each key-value pair 
    literals:
      - {}
      - 1  # value to add
    instruction_params:
      object_create_params:
        - dest: 0
          template_literal_idx: 0
          literal_key_fields: []
          fields: []
      comprehension_begin_params:
        - mode: "Object"
          collection_reg: 1
          key_reg: 4
          value_reg: 5
          body_start: 3
          comprehension_end: 9
      loop_params:
        - mode: "ForEach"
          collection: 0
          key_reg: 4
          value_reg: 5
          result_reg: 8
          body_start: 4
          loop_end: 9
    instructions:
      - "ObjectCreate { params_index: 0 }"             
      - "ComprehensionBegin { params_index: 0 }"  # Start object comprehension
      - "LoopStart { params_index: 0 }"     # Start loop over object elements
      - "Load { dest: 6, literal_idx: 1 }"  # Load 1 into register 6  
      - "Add { dest: 7, left: 5, right: 6 }" # Add 1 to current value
      - "ComprehensionYield { value_reg: 7 }"  # Add result to comprehension (object comprehension needs special handling)
      - "LoadBool { dest: 8, value: true }" # Load true (condition always passes)
      - "AssertCondition { condition: 8 }"  # Assert true condition
      - "LoopNext { body_start: 4, loop_end: 9 }"  # Continue to next iteration or exit
      - "Return { value: 1 }"               # Return the result object (should be empty)
    want_result: {}

  - note: existential_empty_set
    description: Existential quantification on empty set should return false
    example_rego: |
      # some x in set()
      # x > 0  # false - no elements in set
    literals:
      - {}
      - 0  # comparison value
    instruction_params:
      loop_params:
        - mode: "Any"
          collection: 0
          key_reg: 4
          value_reg: 5
          result_reg: 6
          body_start: 2
          loop_end: 6
    instructions:
      - "SetNew { dest: 0 }"                # Create empty set in register 0
      - "LoopStart { params_index: 0 }"
      - "Load { dest: 7, literal_idx: 1 }"  # Load comparison value 0
      - "Gt { dest: 8, left: 5, right: 7 }" # Check if current value > 0
      - "AssertCondition { condition: 8 }"  # Assert the condition
      - "LoopNext { body_start: 2, loop_end: 6 }"
      - "Return { value: 6 }"               # Return false for empty set
    want_result: false

  - note: universal_empty_object
    description: Universal quantification on empty object should return true
    example_rego: |
      # every k, v in {}
      # v > 0  # true - vacuously true (no key-value pairs to violate condition)
    literals:
      - {}
      - 0  # comparison value
    instruction_params:
      object_create_params:
        - dest: 0
          template_literal_idx: 0
          literal_key_fields: []
          fields: []
      loop_params:
        - mode: "Every"
          collection: 0
          key_reg: 4
          value_reg: 5
          result_reg: 6
          body_start: 2
          loop_end: 6
    instructions:
      - "ObjectCreate { params_index: 0 }"             
      - "LoopStart { params_index: 0 }"
      - "Load { dest: 7, literal_idx: 1 }"  # Load comparison value 0
      - "Gt { dest: 8, left: 5, right: 7 }" # Check if current value > 0
      - "AssertCondition { condition: 8 }"  # Assert the condition
      - "LoopNext { body_start: 2, loop_end: 6 }"
      - "Return { value: 6 }"               # Return true for empty object (vacuously true)
    want_result: true

  - note: nested_empty_comprehensions
    description: Nested comprehensions with empty collections
    example_rego: |
      # [[y | y = []; true] | x = []; true]  # []
      # Nested array comprehension where both inner and outer collections are empty
    literals: []
    instruction_params:
      comprehension_begin_params:
        - mode: "Array"
          collection_reg: 0
          key_reg: 2
          value_reg: 3
          body_start: 3
          comprehension_end: 16
        - mode: "Array"
          collection_reg: 6
          key_reg: 8
          value_reg: 9
          body_start: 7
          comprehension_end: 12
      loop_params:
        - mode: "ForEach"
          collection: 0
          key_reg: 2
          value_reg: 3
          result_reg: 10
          body_start: 4
          loop_end: 16
        - mode: "ForEach"
          collection: 6
          key_reg: 8
          value_reg: 9
          result_reg: 11
          body_start: 8
          loop_end: 12
    instructions:
      - "ArrayNew { dest: 0 }"              # Create empty outer array in register 0
      - "ArrayNew { dest: 1 }"              # Create empty result array in register 1
      - "ComprehensionBegin { params_index: 0 }"
      - "LoopStart { params_index: 0 }"     # Start outer loop
      # Inner array comprehension (for each x in outer empty array)
      - "ArrayNew { dest: 6 }"              # Create empty inner array in register 6
      - "ArrayNew { dest: 7 }"              # Create result for inner comprehension in register 7
      - "ComprehensionBegin { params_index: 1 }"
      - "LoopStart { params_index: 1 }"     # Start inner loop
      - "ComprehensionYield { value_reg: 9 }"    # Push inner value to inner result (never executes)
      - "LoadBool { dest: 10, value: true }" # Load true
      - "AssertCondition { condition: 10 }" # Assert true condition for inner loop
      - "LoopNext { body_start: 8, loop_end: 12 }"  # Continue inner loop
      - "ComprehensionYield { value_reg: 7 }"    # Push inner result to outer result
      - "LoadBool { dest: 11, value: true }" # Load true
      - "AssertCondition { condition: 11 }" # Assert true condition for outer loop  
      - "LoopNext { body_start: 4, loop_end: 16 }"  # Continue outer loop
      - "Return { value: 1 }"               # Return the nested result (should be empty)
    want_result: []