# diag.ludic — `--diagnostics=json`: every error and warning the compiler reports, collected and
# written to stdout as one JSON array of {file, line, col, severity, message} when it exits, instead
# of the `file:line: error: message` lines on stderr. The type checker and the module rules (vis,
# uses) report everything they find; an error the parser or the emitter cannot go on from (a token
# it did not expect, an unknown name while lowering) is the last one in the array. A col of 0 is a
# place known only to its line.
var g_diag_json: bool = false
var g_dg_file: []pointer = new []pointer
var g_dg_line: []int = new []int
var g_dg_col: []int = new []int
var g_dg_sev: []pointer = new []pointer
var g_dg_msg: []pointer = new []pointer
var g_dg_errors: int = 0

# one diagnostic, kept for the array - once, though a pass may find it twice (a reference the
# checker and the emitter both resolve)
function diag_add(file: pointer, line: int, col: int, sev: pointer, msg: pointer) -> void {
  var f = file
  if f == null { f = "" }
  let m = diag_trim(msg)
  var i = 0
  while i < len(g_dg_file) {
    if g_dg_line[i] == line and g_dg_col[i] == col and (g_dg_msg[i] == m) and (g_dg_file[i] == f) and (g_dg_sev[i] == sev) { return }
    i += 1
  }
  push(g_dg_file, f)
  push(g_dg_line, line)
  push(g_dg_col, col)
  push(g_dg_sev, sev)
  push(g_dg_msg, m)
  if (sev == "error") { g_dg_errors += 1 }
}
# a message without its closing newline
function diag_trim(m: pointer) -> pointer {
  var n = len(m)
  while n > 0 and (m[n - 1] == '\n' or m[n - 1] == '\r') { n -= 1 }
  return m[0 .. n]
}
# `s` as a JSON string, quotes included, into b
function jq_put(b: Buf, s: pointer) -> void {
  buf_putc(b, '"')
  if s != null {
    var i = 0
    while s[i] != 0 {
      let c = s[i]
      if c == '"' { buf_puts(b, "\\\"") }
      else if c == CH_BACKSLASH { buf_puts(b, "\\\\") }
      else if c == '\n' { buf_puts(b, "\\n") }
      else if c == '\t' { buf_puts(b, "\\t") }
      else if c == '\r' { buf_puts(b, "\\r") }
      else if c >= 0 and c < 32 {
        buf_puts(b, "\\u00")
        buf_putc(b, jq_hex(c >> 4))
        buf_putc(b, jq_hex(c & 15))
      }
      else { buf_putc(b, c) }
      i += 1
    }
  }
  buf_putc(b, '"')
}
function jq_hex(d: int) -> int {
  if d < 10 { return 48 + d }
  return 87 + d
}
# the array, on stdout
function diag_flush() -> void {
  let b = buf_new()
  buf_puts(b, "[")
  var i = 0
  while i < len(g_dg_file) {
    if i > 0 { buf_puts(b, ",") }
    buf_puts(b, "\n  {\"file\": ")
    jq_put(b, g_dg_file[i])
    buf_puts(b, ", \"line\": ")
    buf_puti(b, g_dg_line[i])
    buf_puts(b, ", \"col\": ")
    buf_puti(b, g_dg_col[i])
    buf_puts(b, ", \"severity\": ")
    jq_put(b, g_dg_sev[i])
    buf_puts(b, ", \"message\": ")
    jq_put(b, g_dg_msg[i])
    buf_puts(b, "}")
    i += 1
  }
  if len(g_dg_file) > 0 { buf_puts(b, "\n") }
  buf_puts(b, "]\n")
  let out = file_stdout()
  file_write(out, buf_str(b), b.len)
}
# stop: with --diagnostics=json the array is written first
function diag_exit(code: int) -> void {
  if g_diag_json { diag_flush() }
  exit(code)
}