#!/usr/bin/env fun

/*
 * This file is part of the Fun programming language.
 * https://fun-lang.xyz/
 *
 * Copyright 2026 Johannes Findeisen
 * Licensed under the terms of the Apache-2.0 license.
 * https://opensource.org/license/apache-2-0
 *
 * Added: 2026-04-21
 */

// Interactive showcase script for Fun examples.
// Converted from Bash to Fun.

#include <io/console.fun>
#include <cli.fun>
#include <strings.fun>

// Early argv scan so --help exits before any other side effects
raw_argv = argv()
yes_all = 0
no_all = 0
want_help = 0
idx = 0
argc = len(raw_argv)
while (idx < argc)
  tok = raw_argv[idx]
  if (tok == "--yes")
    yes_all = 1
  else if (tok == "--no")
    no_all = 1
  else if (tok == "--help")
    want_help = 1
  idx = idx + 1

if (want_help == 1)
  print("Usage: scripts/play.fun [--yes | --no] [examples-subdir]")
  print("")
  print("Options:")
  print("  --yes    Run all listed examples without asking")
  print("  --no     Do not run any examples (show list only)")
  print("  --help   Show this help and exit")
  print("")
  print("Behavior:")
  print("  - Without a subdirectory argument: only runs .fun files directly in ./examples/")
  print("  - With an examples-subdir: searches recursively under ./examples/<subdir>/")
  print("")
  print("Environment:")
  print("  FUN_BIN      Path to the fun interpreter (overrides auto-detection)")
  print("  FUN_LIB_DIR  Path to stdlib (defaults to ./lib)")
  print("")
  print("Examples:")
  print("  scripts/play.fun")
  print("  scripts/play.fun --yes")
  print("  scripts/play.fun crypto")
  print("  scripts/play.fun --no math")
  exit(0)

// Set FUN_LIB_DIR to ensure stdlib is found
// We try to use existing environment or default to ./lib
lib_dir = env("FUN_LIB_DIR")
if (len(to_string(lib_dir)) == 0)
  lib_dir = "./lib"

// Discovery logic for the interpreter
fun find_interpreter()
  bin = env("FUN_BIN")
  if (len(to_string(bin)) > 0)
    return bin

  // Check common build locations
  // We use 'system' with 'test -f' as we don't have a direct 'is_file' yet
  if (system("test -f ./build/fun") == 0)
    return "./build/fun"
  if (system("test -f ./build_debug/fun") == 0)
    return "./build_debug/fun"
  if (system("test -f ./build_release/fun") == 0)
    return "./build_release/fun"

  // Check PATH
  if (system("command -v fun >/dev/null 2>&1") == 0)
    return "fun"

  return ""

interpreter = find_interpreter()
if (len(interpreter) == 0)
  print("Error: fun interpreter not found. Please build it or set FUN_BIN.")
  exit(1)

print("Using interpreter: " + interpreter)
print("Searching for examples in ./examples...")

// Recursive file discovery
// Since we don't have a robust recursive os_list_dir yet, 
// and the original used 'find', we'll use 'find' via system to get the list.
fun get_examples(subdir)
  // We use 'find' to get all .fun files and sort them.
  // We redirect to a temporary file as we don't have a 'proc_capture' that returns an array easily
  // Actually, os_list_dir uses 'ls -1'. We can use a similar approach or just call find.

  base_dir = "examples"
  cmd = ""
  if (len(subdir) > 0)
    target = base_dir + "/" + subdir
    // Verify directory exists
    if (system("test -d " + target) != 0)
      print("Error: examples subdirectory not found: " + subdir)
      exit(1)
    cmd = "find " + target + " -name \"*.fun\" | sort > ./tmp/examples_list.txt"
  else
    // Only run scripts directly in the ./examples/ directory when no argument is given.
    cmd = "find " + base_dir + " -maxdepth 1 -name \"*.fun\" | sort > ./tmp/examples_list.txt"

  system(cmd)

  list_str = read_file("./tmp/examples_list.txt")
  // We don't have a built-in 'split' that handles newlines easily in all versions? 
  // Wait, lib/strings.fun might have it.

  lines = str_split(list_str, "\n")

  // Filter out empty lines
  examples = []
  i = 0
  n = len(lines)
  while (i < n)
    line = str_trim(lines[i])
    if (len(line) > 0)
      push(examples, line)
    i = i + 1
  return examples

args = parse_args(raw_argv)
subdir = ""
if (len(args["positionals"]) > 0)
  subdir = args["positionals"][0]

if (yes_all == 1 && no_all == 1)
  print("Error: --yes and --no cannot be used together.")
  exit(2)

examples = get_examples(subdir)
if (len(examples) == 0)
  if (len(subdir) > 0)
    print("No examples found in ./examples/" + subdir)
  else
    print("No examples found in ./examples")
  exit(0)

failed_examples = []
console = Console()

i = 0
n = len(examples)
while (i < n)
  example = examples[i]
  print("--------------------------------------------------------------------------------")
  print("Example: " + example)

  // ask_yes_no returns 1 for yes, 0 for no
  run_it = 0
  if (yes_all == 1)
    // Auto-approve running
    run_it = 1
  else if (no_all == 1)
    // Auto-decline
    run_it = 0
  else
    print("Do you want to run this example? [y/N]")
    ans = str_to_lower(str_trim(input("")))
    if (ans == "y" || ans == "yes")
      run_it = 1
    else
      run_it = 0

  if (run_it == 1)
    print("Running: " + interpreter + " " + example)

    // Prepare command with environment variable
    // FUN_LIB_DIR must be passed to the child process
    cmd = "FUN_LIB_DIR=\"" + lib_dir + "\" " + interpreter + " " + example
    exit_code = system(cmd)

    print("Exit code: " + to_string(exit_code))
    if (exit_code != 0)
      push(failed_examples, example + " (exit code: " + to_string(exit_code) + ")")
  else
    print("Skipping.")

  i = i + 1

print("--------------------------------------------------------------------------------")
print("Done.")

if (len(failed_examples) > 0)
  print("The following examples failed:")
  i = 0
  while (i < len(failed_examples))
    print("  - " + failed_examples[i])
    i = i + 1
  exit(1)

exit(0)