;; Go evaluator tests.

(define go-eval-test-count 0)
(define go-eval-test-pass 0)
(define go-eval-test-fails (list))

(define
  go-eval-test
  (fn
    (name actual expected)
    (set! go-eval-test-count (+ go-eval-test-count 1))
    (if
      (= actual expected)
      (set! go-eval-test-pass (+ go-eval-test-pass 1))
      (append! go-eval-test-fails {:name name :expected expected :actual actual}))))

(define gtev (fn (env src) (go-eval env (go-parse src))))

;; ── env ──────────────────────────────────────────────────────────
(go-eval-test
  "env: empty lookup returns nil"
  (go-env-lookup go-env-empty "x")
  nil)

(go-eval-test
  "env: extend then lookup"
  (go-env-lookup (go-env-extend go-env-empty "x" 42) "x")
  42)

;; ── literals ────────────────────────────────────────────────────
(go-eval-test "lit: 42 → 42" (gtev go-env-empty "42") 42)

(go-eval-test "lit: 0 → 0" (gtev go-env-empty "0") 0)

(go-eval-test "lit: 0xFF → 255" (gtev go-env-empty "0xFF") 255)

(go-eval-test "lit: 0b1010 → 10" (gtev go-env-empty "0b1010") 10)

(go-eval-test "lit: 0o17 → 15" (gtev go-env-empty "0o17") 15)

(go-eval-test
  "lit: underscore separator 1_000 → 1000"
  (gtev go-env-empty "1_000")
  1000)

(go-eval-test "lit: string" (gtev go-env-empty "\"hello\"") "hello")

;; ── predeclared ─────────────────────────────────────────────────
(go-eval-test "var: true" (gtev go-env-empty "true") true)
(go-eval-test "var: false" (gtev go-env-empty "false") false)
(go-eval-test "var: nil" (gtev go-env-empty "nil") nil)

;; ── variable lookup ─────────────────────────────────────────────
(go-eval-test
  "var: bound x → 5"
  (go-eval (go-env-extend go-env-empty "x" 5) (go-parse "x"))
  5)

(go-eval-test
  "var: unbound y → :eval-error"
  (gtev go-env-empty "y")
  (list :eval-error :unbound "y"))

;; ── binary ops ─────────────────────────────────────────────────
(go-eval-test "binop: 1 + 2 → 3" (gtev go-env-empty "1 + 2") 3)
(go-eval-test "binop: 10 - 4 → 6" (gtev go-env-empty "10 - 4") 6)
(go-eval-test "binop: 3 * 7 → 21" (gtev go-env-empty "3 * 7") 21)
(go-eval-test "binop: 42 / 7 → 6" (gtev go-env-empty "42 / 7") 6)
(go-eval-test
  "binop: 2 + 3 * 4 → 14 (prec)"
  (gtev go-env-empty "2 + 3 * 4")
  14)
(go-eval-test
  "binop: a + b uses env"
  (go-eval
    (go-env-extend (go-env-extend go-env-empty "a" 3) "b" 4)
    (go-parse "a + b"))
  7)

(go-eval-test "binop: 1 < 2 → true" (gtev go-env-empty "1 < 2") true)
(go-eval-test "binop: 5 == 5 → true" (gtev go-env-empty "5 == 5") true)
(go-eval-test "binop: 5 != 5 → false" (gtev go-env-empty "5 != 5") false)
(go-eval-test
  "binop: true && false → false"
  (gtev go-env-empty "true && false")
  false)
(go-eval-test
  "binop: false || true → true"
  (gtev go-env-empty "false || true")
  true)

;; ── report ──────────────────────────────────────────────────────
(go-eval-test
  "var-decl: var x = 5 — env has x=5"
  (go-env-lookup
    (go-eval-program go-env-empty (list (go-parse "var x = 5")))
    "x")
  5)

(go-eval-test
  "short-decl: a, b := 3, 4 — env has both"
  (let
    ((env (go-eval-program go-env-empty (list (go-parse "a, b := 3, 4")))))
    (list (go-env-lookup env "a") (go-env-lookup env "b")))
  (list 3 4))

(go-eval-test
  "assign: x = 5 then x → 5"
  (let
    ((env (go-eval-program (go-env-extend go-env-empty "x" 1) (list (go-parse "x = 5")))))
    (go-env-lookup env "x"))
  5)

(go-eval-test
  "if: true branch evaluates"
  (let
    ((env (go-eval-program (go-env-extend go-env-empty "x" 0) (list (go-parse "if true { x = 1 }")))))
    (go-env-lookup env "x"))
  1)

(go-eval-test
  "if-else: false → else branch"
  (let
    ((env (go-eval-program (go-env-extend go-env-empty "x" 0) (list (go-parse "if false { x = 1 } else { x = 2 }")))))
    (go-env-lookup env "x"))
  2)

(go-eval-test
  "fn: define + call — double(7) = 14"
  (let
    ((env (go-eval-program go-env-empty (list (go-parse "func double(x int) int { return x * 2 }")))))
    (go-eval env (go-parse "double(7)")))
  14)

(go-eval-test
  "fn: add(2, 3) = 5"
  (let
    ((env (go-eval-program go-env-empty (list (go-parse "func add(x, y int) int { return x + y }")))))
    (go-eval env (go-parse "add(2, 3)")))
  5)

(go-eval-test
  "fn: recursive fib(5) = 5"
  (let
    ((env (go-eval-program go-env-empty (list (go-parse "func fib(n int) int { if n < 2 { return n } return fib(n-1) + fib(n-2) }")))))
    (go-eval env (go-parse "fib(5)")))
  5)

(go-eval-test
  "for: count to 10 with sum"
  (let
    ((env (go-eval-program go-env-empty (list (go-parse "var sum = 0") (go-parse "for i := 0; i < 10; i++ { sum = sum + i }")))))
    (go-env-lookup env "sum"))
  45)

(go-eval-test
  "inc-dec: x++ updates env"
  (let
    ((env (go-eval-program (go-env-extend go-env-empty "x" 5) (list (go-parse "x++")))))
    (go-env-lookup env "x"))
  6)

(go-eval-test
  "inc-dec: x-- updates env"
  (let
    ((env (go-eval-program (go-env-extend go-env-empty "x" 5) (list (go-parse "x--")))))
    (go-env-lookup env "x"))
  4)

(go-eval-test
  "for: break exits the loop"
  (let
    ((env (go-eval-program go-env-empty (list (go-parse "var i = 0") (go-parse "for i < 100 { if i == 5 { break } ; i++ }")))))
    (go-env-lookup env "i"))
  5)

(go-eval-test
  "for: continue skips body but runs post"
  (let
    ((env (go-eval-program go-env-empty (list (go-parse "var sum = 0") (go-parse "for i := 0; i < 5; i++ { if i == 2 { continue } ; sum = sum + i }")))))
    (go-env-lookup env "sum"))
  8)

(go-eval-test
  "for: infinite + break with sum"
  (let
    ((env (go-eval-program go-env-empty (list (go-parse "var s = 0") (go-parse "var i = 1") (go-parse "for { if i > 4 { break } ; s = s + i ; i++ }")))))
    (go-env-lookup env "s"))
  10)

(go-eval-test
  "fn: iterative factorial via for-loop"
  (let
    ((env (go-eval-program go-env-empty (list (go-parse "func fact(n int) int { r := 1 ; for i := 2 ; i <= n ; i++ { r = r * i } ; return r }")))))
    (go-eval env (go-parse "fact(5)")))
  120)

(go-eval-test
  "slice: []int{1,2,3} → :go-slice"
  (gtev go-env-empty "[]int{1, 2, 3}")
  (list :go-slice (list 1 2 3)))

(go-eval-test
  "index: a[0] = 10, a[2] = 30"
  (let
    ((env (go-eval-program go-env-empty (list (go-parse "a := []int{10, 20, 30}")))))
    (list (go-eval env (go-parse "a[0]")) (go-eval env (go-parse "a[2]"))))
  (list 10 30))

(go-eval-test
  "index: out-of-range error"
  (let
    ((env (go-eval-program go-env-empty (list (go-parse "a := []int{1, 2}")))))
    (go-eval env (go-parse "a[5]")))
  (list :eval-error :index-out-of-range 5 2))

(go-eval-test
  "builtin: len(slice) = 3"
  (let
    ((env (go-eval-program go-env-builtins (list (go-parse "a := []int{1, 2, 3}")))))
    (go-eval env (go-parse "len(a)")))
  3)

(go-eval-test
  "builtin: len(string)"
  (go-eval go-env-builtins (go-parse "len(\"hello\")"))
  5)

(go-eval-test
  "builtin: append(a, 4, 5)"
  (let
    ((env (go-eval-program go-env-builtins (list (go-parse "a := []int{1, 2, 3}")))))
    (go-eval env (go-parse "append(a, 4, 5)")))
  (list
    :go-slice (list 1 2 3 4 5)))

(go-eval-test
  "slice expr: a[1:3]"
  (let
    ((env (go-eval-program go-env-empty (list (go-parse "a := []int{10, 20, 30, 40}")))))
    (go-eval env (go-parse "a[1:3]")))
  (list :go-slice (list 20 30)))

(go-eval-test
  "slice expr: a[:2] (omitted low)"
  (let
    ((env (go-eval-program go-env-empty (list (go-parse "a := []int{1, 2, 3, 4}")))))
    (go-eval env (go-parse "a[:2]")))
  (list :go-slice (list 1 2)))

(go-eval-test
  "slice expr: a[2:] (omitted high)"
  (let
    ((env (go-eval-program go-env-empty (list (go-parse "a := []int{1, 2, 3, 4}")))))
    (go-eval env (go-parse "a[2:]")))
  (list :go-slice (list 3 4)))

(go-eval-test
  "fn: sum slice via for-loop with len + index"
  (let
    ((env (go-eval-program go-env-builtins (list (go-parse "a := []int{1, 2, 3, 4, 5}") (go-parse "sum := 0") (go-parse "for i := 0; i < len(a); i++ { sum = sum + a[i] }")))))
    (go-env-lookup env "sum"))
  15)

(go-eval-test
  "map: map[string]int{...} → :go-map"
  (gtev go-env-empty "map[string]int{\"a\": 1, \"b\": 2}")
  (list :go-map (list (list "a" 1) (list "b" 2))))

(go-eval-test
  "map: m[\"a\"] → 1"
  (let
    ((env (go-eval-program go-env-empty (list (go-parse "m := map[string]int{\"a\": 1, \"b\": 2}")))))
    (go-eval env (go-parse "m[\"a\"]")))
  1)

(go-eval-test
  "map: missing key → nil (v0 stand-in for zero value)"
  (let
    ((env (go-eval-program go-env-empty (list (go-parse "m := map[string]int{\"a\": 1}")))))
    (go-eval env (go-parse "m[\"missing\"]")))
  nil)

(go-eval-test
  "map: len(m) = 2"
  (let
    ((env (go-eval-program go-env-builtins (list (go-parse "m := map[string]int{\"a\": 1, \"b\": 2}")))))
    (go-eval env (go-parse "len(m)")))
  2)

(go-eval-test
  "map: index-assign updates existing key"
  (let
    ((env (go-eval-program go-env-empty (list (go-parse "m := map[string]int{\"a\": 1}") (go-parse "m[\"a\"] = 99")))))
    (go-eval env (go-parse "m[\"a\"]")))
  99)

(go-eval-test
  "map: index-assign adds new key"
  (let
    ((env (go-eval-program go-env-empty (list (go-parse "m := map[string]int{}") (go-parse "m[\"new\"] = 7")))))
    (go-eval env (go-parse "m[\"new\"]")))
  7)

(go-eval-test
  "slice: index-assign a[0] = 99"
  (let
    ((env (go-eval-program go-env-empty (list (go-parse "a := []int{10, 20, 30}") (go-parse "a[0] = 99")))))
    (go-eval env (go-parse "a[0]")))
  99)

(go-eval-test
  "map: word count via loop"
  (let
    ((env (go-eval-program go-env-builtins (list (go-parse "words := []string{\"a\", \"b\", \"a\", \"c\", \"a\"}") (go-parse "counts := map[string]int{}") (go-parse "for i := 0; i < len(words); i++ { counts[words[i]] = counts[words[i]] + 1 }")))))
    (go-eval env (go-parse "counts[\"a\"]")))
  3)

(define
  go-eval-test-summary
  (str "eval " go-eval-test-pass "/" go-eval-test-count))