// tests.vr — functions named test_* are picked up by `vr test`.
//   vr test examples/tests.vr

import os
import json
import strings
import math
import http
import time

enum Suit {
	hearts
	diamonds
	clubs
	spades
}

fn add(a, b) {
	return a + b
}

fn test_add() {
	assert add(2, 3) == 5
	assert add(-1, 1) == 0
}

fn test_strings() {
	let a = "foo"
	let b = "bar"
	assert a + b == "foobar"
	assert a != b
	assert a == "foo"
}

fn test_loops() {
	mut total = 0
	mut i = 1
	while i <= 10 {
		total = total + i
		i = i + 1
	}
	assert total == 55
}

fn test_booleans() {
	let x = 7
	assert x > 3 and x < 10
	assert x == 7 or x == 8
	assert not (x == 0)
}

fn test_arrays() {
	let a = [1, 2, 3]
	assert len(a) == 3
	assert a[0] == 1
	assert a[2] == 3
	a[1] = 42
	assert a[1] == 42
	push(a, 4)
	assert len(a) == 4
	assert a[3] == 4
	let m = [[1, 2], [3, 4]]
	assert m[1][0] == 3
}

fn test_for_range() {
	mut total = 0
	for i in 0..5 {
		total = total + i
	}
	assert total == 10 // 0+1+2+3+4
	mut inc = 0
	for i in 1...3 {
		inc = inc + i
	}
	assert inc == 6 // 1+2+3 (inclusive)
}

fn test_for_in() {
	let a = [5, 6, 7]
	mut total = 0
	for x in a {
		total = total + x
	}
	assert total == 18
	let squares = []
	for i in 0..4 {
		push(squares, i * i)
	}
	assert squares == squares // identity comparison
	assert len(squares) == 4
	assert squares[3] == 9
}

fn test_break_continue() {
	// break exits the loop early
	mut total = 0
	for i in 0..100 {
		if i == 5 {
			break
		}
		total = total + i
	}
	assert total == 10 // 0+1+2+3+4

	// continue skips to the next iteration
	mut sum = 0
	for i in 0..6 {
		if i == 3 {
			continue
		}
		sum = sum + i
	}
	assert sum == 12 // 0+1+2+4+5 (3 skipped)

	// break and continue in while loops
	mut n = 0
	while true {
		n = n + 1
		if n == 3 {
			continue
		}
		if n == 5 {
			break
		}
	}
	assert n == 5

	// continue advances the iterator in for-in loops (no infinite loop)
	let odds = []
	for x in [1, 2, 3, 4, 5] {
		if x % 2 == 0 {
			continue
		}
		push(odds, x)
	}
	assert odds == odds
	assert len(odds) == 3
	assert odds[2] == 5
}

fn test_else_if() {
	let score = 85
	mut grade = ""
	if score >= 90 {
		grade = "A"
	} else if score >= 80 {
		grade = "B"
	} else if score >= 70 {
		grade = "C"
	} else {
		grade = "F"
	}
	assert grade == "B"
	assert 10 > 5
}

fn test_match() {
	mut total = 0
	match 2 {
		1 {
			total = total + 1
		}
		2 {
			total = total + 10
		}
		else {
			total = total + 100
		}
	}
	assert total == 10 // matched the 2 arm

	// match on strings
	let word = "cat"
	mut sound = ""
	match word {
		"dog" {
			sound = "woof"
		}
		"cat" {
			sound = "meow"
		}
		else {
			sound = "?"
		}
	}
	assert sound == "meow"

	// no else arm: nothing runs when nothing matches
	mut hit = 0
	match 99 {
		1 {
			hit = 1
		}
		2 {
			hit = 2
		}
	}
	assert hit == 0
}

fn test_structs() {
	let p = { name: "bob", age: 30 }
	assert p.name == "bob"
	assert p.age == 30
	p.age = 31
	assert p.age == 31

	// structs are reference values
	let q = p
	q.age = 40
	assert p.age == 40

	// nested structs
	let person = { name: "amy", addr: { city: "nyc", zip: 10001 } }
	assert person.addr.city == "nyc"
	person.addr.zip = 90001
	assert person.addr.zip == 90001

	// structs in arrays
	let pts = [{ x: 1, y: 2 }, { x: 10, y: 20 }]
	assert pts[1].x == 10
	pts[0].x = 99
	assert pts[0].x == 99

	// arrays in structs
	let holder = { items: [1, 2, 3] }
	holder.items[1] = 42
	assert holder.items[1] == 42

	// structs passed to and returned from functions
	let pt = { x: 3, y: 4 }
	assert pt.x * pt.x + pt.y * pt.y == 25

	// identity comparison
	let a = { n: 1 }
	let b = a
	let c = { n: 1 }
	assert a == b
	assert a != c
}

fn test_json() {
	// encoding
	assert json_encode(42) == "42"
	assert json_encode(3.14) == "3.14"
	assert json_encode(1.0) == "1"
	assert json_encode("hi") == "\"hi\""
	assert json_encode([1, "two", 3.5]) == "[1,\"two\",3.5]"
	let rec = { name: "amy", age: 30 }
	assert json_encode(rec) == "{\"name\":\"amy\",\"age\":30}"
	assert json_encode(none) == "null"

	// decoding
	assert json_decode("42") == 42
	assert json_decode("3.14") == 3.14
	assert json_decode("\"hi\"") == "hi"
	assert json_decode("true") == 1
	assert json_decode("null") == none
	let obj = json_decode("{\"x\": 1, \"y\": [1, 2], \"z\": {\"deep\": true}}")
	assert obj.x == 1
	assert obj.y[1] == 2
	assert obj.z.deep == 1

	// round-trip
	assert json_encode(json_decode("{\"a\": 1, \"b\": [2, 3]}")) == "{\"a\":1,\"b\":[2,3]}"

	// unicode escapes
	assert json_decode("\"\\u0041\"") == "A"
	assert json_decode("\"\\ud83d\\ude00\"") == "😀"
}

fn test_format() {
	assert format(42, "%d") == "42"
	assert format(42, "%05d") == "00042"
	assert format(-42, "%05d") == "-0042"
	assert format(42, "%-5d") == "42   "
	assert format(3.14159, "%.2f") == "3.14"
	assert format(3.0, "%.2f") == "3.00"
	assert format(255, "%X") == "FF"
	assert format("hi", "%s") == "hi"
	assert format(7, "%5d") == "    7"
}

fn test_string_tools() {
	assert replace("hello world", "l", "L") == "heLLo worLd"
	assert "hello world".replace("o", "0") == "hell0 w0rld"
	assert len(split_lines("a\nb\nc")) == 3
	assert "a\nb".split_lines()[1] == "b"
	assert pad("x", 4) == "x   "
	assert "x".pad(4) == "x   "
	assert pad_left("x", 4) == "   x"
	assert "x".pad_left(4) == "   x"
	assert repeat("ab", 3) == "ababab"
	assert "ab".repeat(2) == "abab"
	assert pad("toolong", 2) == "toolong"
}

fn test_none() {
	assert none == none
	assert none == 0 == false
	assert none != 5
	if none {
		assert false
	}
	assert not (none == 1)
}

fn test_module_imports() {
	// os module
	if not os.exists("examples") {
		assert false
	}
	if not os.is_dir("examples") {
		assert false
	}
	if not os.is_file("main.v") {
		assert false
	}
	assert os.base("a/b/c.vr") == "c.vr"
	assert os.dir("a/b/c.vr") == "a/b"
	assert len(os.glob("lib/*.vr")) == 10
	let tmp = os.join(os.cwd(), "tmp_test.txt")
	os.write_lines(tmp, ["x", "y"])
	assert len(os.read_lines(tmp)) == 2
	os.remove(tmp)

	// json module
	let data = json.decode("{\"a\": 1, \"b\": [2, 3]}")
	assert json.encode(data) == "{\"a\":1,\"b\":[2,3]}"
	assert strings.contains(json.pretty(data), "\n")

	// strings module
	assert strings.join(["a", "b"], "-") == "a-b"
	assert strings.capitalize("hello") == "Hello"
	assert strings.replace("foo", "o", "0") == "f00"
	assert strings.pad_left("7", 3) == "  7"
	assert strings.format(3.14159, "%.2f") == "3.14"

	// math module
	assert math.clamp(150, 0, 100) == 100
	assert math.sign(-3) == -1
	assert math.abs(-7) == 7
}

fn test_native_errors_are_catchable() {
	try {
		read_file("/no/such/file.vr")
		assert false
	} catch e {
		assert len(e) > 0
	}
	try {
		json_decode("not json")
		assert false
	} catch e {
		assert len(e) > 0
	}
}

fn test_closures() {
	// closures in expression contexts must not corrupt surrounding values
	let pick = fn (x) {
		if x > 10 {
			return "big"
		}
		return "small"
	}
	assert "a: " + pick(50) == "a: big"
	assert pick(3) + "!" == "small!"
	assert pick(50) + " " + pick(3) == "big small"
	let dbl = fn (x) {
		return x * 2
	}
	assert str(dbl(21)) == "42"
	assert "v=" + str(dbl(4)) == "v=8"
	// closure containing a loop
	let sum = fn () {
		mut total = 0
		for i in 0..5 {
			total = total + i
		}
		return total
	}
	assert sum() == 10
	// closure call as a statement argument
	let tag = fn (t) {
		return "[" + t + "]"
	}
	assert tag("warn") == "[warn]"
}

fn test_enums() {
	// variant values
	assert Suit.hearts == 0
	assert Suit.spades == 3
	// enum.count()
	assert Suit.hearts.count() == 4
	// enum.to_string()
	assert Suit.spades.to_string() == "spades"
	// enums in expressions
	let next = Suit.hearts + 1
	assert next == 1
	// enum iteration
	mut names = []
	for s in Suit {
		names = push(names, s.to_string())
	}
	assert len(names) == 4
	assert names[0] == "hearts"
	assert names[3] == "spades"
	// match on enum values
	assert suit_code(Suit.clubs) == "c"
	assert suit_code(Suit.hearts) == "h"
}

fn suit_code(s) {
	match s {
		Suit.hearts { return "h" }
		Suit.clubs { return "c" }
		else { return "?" }
	}
}

fn test_http_errors() {
	// offline-safe: connecting to a closed local port fails fast
	try {
		http.get("http://127.0.0.1:1/nope")
		assert false
	} catch e {
		assert len(e) > 0
	}
}

fn test_time() {
	let t = time.now()
	assert t > 1700000000
	// format produces fixed-width strings
	let day = time.date(t)
	assert len(day) == 10
	assert day[4] == "-"[0]
	let full = time.format(t, "YYYY-MM-DD HH:mm:ss")
	assert len(full) == 19
	// parse round-trips within a second
	let back = time.parse(full)
	assert abs(back - t) <= 1
	// ms is more precise than seconds
	assert time.ms() > t * 1000
	// invalid input throws
	try {
		time.parse("not a date")
		assert false
	} catch e {
		assert len(e) > 0
	}
}

fn test_closure_capture() {
	// closures capture enclosing locals by value
	let factor = 3
	let dbl = fn(x) {
		return x * factor
	}
	assert dbl(7) == 21

	let name = "alice"
	let age = 30
	let greet = fn() {
		return "hi " + name + " age=" + str(age)
	}
	assert greet() == "hi alice age=30"

	// capture by value: later changes to the outer var don't affect the closure
	mut counter = 10
	let read = fn() {
		return counter
	}
	assert read() == 10
	counter = 99
	assert read() == 10

	// nested closures capture through both levels
	let base = 100
	let outer = fn() {
		let mid = 5
		let inner = fn(x) {
			return base + mid + x
		}
		return inner(1)
	}
	assert outer() == 106

	// assignment to a captured variable writes the closure's own copy
	mut n = 1
	let bump = fn() {
		n = n + 1
		return n
	}
	assert bump() == 2
	assert n == 1

	// closure stored in a struct, called dynamically
	let handler = fn() {
		return "handled"
	}
	let rec = { run: handler }
	assert rec.run() == "handled"
}

fn test_dynamic_map_keys() {
	// map keys may be computed expressions, not just string literals
	let m = {}
	for i in 0..3 {
		m["key" + str(i)] = i * 10
	}
	assert m["key0"] == 0
	assert m["key2"] == 20
	let k = "key1"
	assert m[k] == 10
	assert has(m, "key1") == 1
	assert len(m) == 3
	delete(m, "key1")
	assert has(m, "key1") == 0
	assert len(m) == 2
	// nested computed access
	let cfg = { "db": { "host": "localhost", "port": 5432 } }
	let which = "db"
	assert cfg[which]["host"] == "localhost"
}

fn test_sort_large() {
	// merge sort must handle large arrays (O(n log n)) and stay sorted
	mut a = []
	let n = 2000
	mut i = 0
	while i < n {
		a = push(a, (n - i) % 97)
		i = i + 1
	}
	sort(a)
	assert len(a) == n
	mut ok = 1
	mut j = 1
	while j < n {
		if a[j - 1] > a[j] {
			ok = 0
		}
		j = j + 1
	}
	assert ok == 1
	assert a[0] == 0
	assert a[n - 1] == 96
}

fn test_mutable_bindings() {
	// `let` is immutable: reassignment is a compile-time error (tested in CI)
	// `mut` opts into reassignment
	mut counter = 0
	counter = counter + 1
	counter = counter + 2
	assert counter == 3
	// `let` still reads fine and does not accept reassignment
	let fixed = 42
	assert fixed == 42
}

fn test_string_builder() {
	// string builders avoid O(n^2) reallocation of repeated `+`
	mut sb = strings.builder()
	for i in 0..10 {
		sb = strings.build_add(sb, "x" + str(i) + ",")
	}
	let out = strings.build_str(sb)
	assert out == "x0,x1,x2,x3,x4,x5,x6,x7,x8,x9,"
}

fn test_spawn_join() {
	// spawn runs a closure on an OS thread; spawn_join waits and returns
	let j1 = spawn(worker_sum, 100)
	let j2 = spawn(worker_sum, 200)
	let r1 = spawn_join(j1)
	let r2 = spawn_join(j2)
	assert r1 == 4950
	assert r2 == 19900
}

fn worker_sum(n) {
	mut s = 0
	mut i = 0
	while i < n {
		s = s + i
		i = i + 1
	}
	return s
}

fn test_spawn_string_result() {
	let j = spawn(worker_greet, "world")
	let res = spawn_join(j)
	assert res == "hello world"
}

fn worker_greet(name) {
	return "hello " + name
}

fn test_spawn_error_propagation() {
	mut caught = false
	try {
		let j = spawn(worker_boom)
		let r = spawn_join(j)
		assert r == 0
	} catch e {
		caught = true
	}
	assert caught
}

fn worker_boom() {
	let x = 1 / 0
	return x
}

fn test_string_coercion() {
	// String + any value stringifies, so error messages "just work"
	let e = { code: 403, msg: "forbidden" }
	assert "err: " + e == "err: {code: 403, msg: forbidden}"
	assert "n=" + 42 == "n=42"
	assert "f=" + 3.5 == "f=3.5"
	assert "a=" + [1, 2] == "a=[1, 2]"
	assert "b=" + none == "b=none"
}

fn test_typed_throw() {
	// throw and catch arbitrary values (structs, ints, floats)
	mut got = ""
	try {
		throw { reason: "boom" }
	} catch err {
		got = "" + err
	}
	assert got == "{reason: boom}"

	mut gotn = -1
	try {
		throw 99
	} catch err {
		gotn = int(err)
	}
	assert gotn == 99
}

fn test_flag_parsing() {
	// flags are read from args() at runtime; here we check the lookup helpers
	// behave with no flags (defaults) — the actual parse is exercised in CI.
	assert flag_val("missing") == ""
	assert flag_has("missing") == 0
	assert len(flag_positional()) == 0
}

fn test_failing() {
	// this one is meant to fail — shows up in `vr test` output
	assert 1 == 2
}