// Moved from apps/selfhost-compiler/boxes/parser/parser_box.hako
// ParserBox — Stage‑1 JSON v0 generator (coordinator, delegates to specialized boxes)
// Responsibility: Coordinate parsing, manage state, delegate to specialized boxes
// API: parse_program2(src) -> JSON

using sh_core as StringHelpers  // Required: ParserStringUtilsBox depends on this (using chain unresolved)
using lang.compiler.parser.scan.parser_string_utils_box
using lang.compiler.parser.scan.parser_ident_scan_box
using lang.compiler.parser.scan.parser_string_scan_box
using lang.compiler.parser.using.using_collector_box
using lang.compiler.parser.expr.parser_expr_box
using lang.compiler.parser.stmt.parser_stmt_box
using lang.compiler.parser.stmt.parser_control_box

box ParserBox {
  gpos
  usings_json
  externs_json
  stage3

  birth() {
    me.gpos = 0
    me.usings_json = "[]"
    me.externs_json = "[]"
    me.stage3 = 0
    return 0
  }

  stage3_enable(flag) {
    if flag == null { flag = 0 }
    if flag == 0 { me.stage3 = 0 } else { me.stage3 = 1 }
    return 0
  }

  stage3_enabled() {
    if me.stage3 == 1 { return 1 }
    return 0
  }

  // === State management ===
  gpos_set(i) { me.gpos = i return 0 }
  gpos_get() { return me.gpos }

  // === JSON utilities ===
  esc_json(s) {
    local out = ""
    local i = 0
    local n = s.length()
    loop(i < n) {
      local ch = s.substring(i, i+1)
      if ch == "\\" { out = out + "\\\\" }
      else { if ch == "\"" { out = out + "\\\"" }
      else { out = out + ch } }
      i = i + 1
    }
    return out
  }

  // === Delegation to ParserStringUtilsBox ===
  is_digit(ch) { return ParserStringUtilsBox.is_digit(ch) }

  is_space(ch) { return ParserStringUtilsBox.is_space(ch) }

  is_alpha(ch) { return ParserStringUtilsBox.is_alpha(ch) }

  starts_with(src, i, pat) { return ParserStringUtilsBox.starts_with(src, i, pat) }

  index_of(src, i, pat) { return ParserStringUtilsBox.index_of(src, i, pat) }

  trim(s) { return ParserStringUtilsBox.trim(s) }

  starts_with_kw(src, i, kw) { return ParserStringUtilsBox.starts_with_kw(src, i, kw) }

  i2s(v) { return ParserStringUtilsBox.i2s(v) }

  to_int(s) { return ParserStringUtilsBox.to_int(s) }

  skip_ws(src, i) { return ParserStringUtilsBox.skip_ws(src, i) }

  // === Delegation to scanner boxes ===
  read_ident2(src, i) { return ParserIdentScanBox.scan_ident(src, i) }

  read_string_lit(src, i) {
    local pair = ParserStringScanBox.scan(src, i)
    local at = pair.lastIndexOf("@")
    local content = pair.substring(0, at)
    local pos = 0
    if at >= 0 { pos = me.to_int(pair.substring(at+1, pair.length())) }
    else { pos = i }
    me.gpos_set(pos)
    return content
  }

  // === using system ===
  add_using(kind, target, alias) {
    local cur = me.usings_json
    if cur == null || cur.length() == 0 { cur = "[]" }

    local name = ""
    local path = null

    if kind == "path" {
      path = target
      if alias != null {
        name = alias
      } else {
        local p = target
        local idx = -1
        local t = 0
        loop(t < p.length()) {
          if p.substring(t,t+1) == "/" { idx = t }
          t = t + 1
        }
        if idx >= 0 { p = p.substring(idx+1, p.length()) }

        if p.length() > 5 && me.starts_with(p, p.length()-5, ".hako") == 1 {
          p = p.substring(0, p.length()-5)
        } else {
          if p.length() > 6 && me.starts_with(p, p.length()-6, ".nyash") == 1 {
            p = p.substring(0, p.length()-6)
          }
        }
        name = p
      }
    } else {
      name = target
      if alias != null { name = alias }
    }

    local entry = "{\"name\":\"" + me.esc_json(name) + "\""
    if path != null { entry = entry + ",\"path\":\"" + me.esc_json(path) + "\"" }
    entry = entry + "}"

    if cur == "[]" {
      me.usings_json = "[" + entry + "]"
      return 0
    }

    local pos = cur.lastIndexOf("]")
    if pos < 0 {
      me.usings_json = "[" + entry + "]"
      return 0
    }

    me.usings_json = cur.substring(0, pos) + "," + entry + "]"
    return 0
  }

  extract_usings(src) {
    me.usings_json = UsingCollectorBox.collect(src)
    return 0
  }

  get_usings_json() {
    return me.usings_json
  }

  // === extern_c annotations ===
  add_extern_c(symbol, func) {
    // Entry shape: {"symbol":"hako_add","func":"Name/Arity"}
    local sym = symbol
    if sym == null { sym = "" }
    local func_name = func
    if func_name == null { func_name = "" }
    local entry = "{\"symbol\":\"" + me.esc_json(sym) + "\",\"func\":\"" + me.esc_json(func_name) + "\"}"
    local cur = me.externs_json
    if cur == null || cur.length() == 0 { cur = "[]" }
    if cur == "[]" {
      me.externs_json = "[" + entry + "]"
      return 0
    }
    local pos = cur.lastIndexOf("]")
    if pos < 0 {
      me.externs_json = "[" + entry + "]"
      return 0
    }
    me.externs_json = cur.substring(0, pos) + "," + entry + "]"
    return 0
  }

  extract_externs(_src) {
    // MVP: rely on ParserStmtBox to call add_extern_c during parse; here no-op for now.
    return 0
  }

  get_externs_json() {
    return me.externs_json
  }

  // === Delegation to ParserExprBox ===
  parse_expr2(src, i) {
    return ParserExprBox.parse_expr2(src, i, me)
  }

  // === Delegation to ParserStmtBox ===
  parse_stmt2(src, i) {
    return ParserStmtBox.parse(src, i, me)
  }

  // === Delegation to ParserControlBox ===
  parse_block2(src, i) {
    return ParserControlBox.parse_block(src, i, me)
  }

  // === Top-level program parser ===
  parse_program2(src) {
    // Inline skip_ws to avoid VM bug: method-with-loop called from within loop
    local i = 0
    local n = src.length()
    if i < n {
      local ws_cont_init = 1
      loop(ws_cont_init == 1) {
        if i < n {
          local ch = src.substring(i, i + 1)
          if ch == " " || ch == "\n" || ch == "\r" || ch == "\t" { i = i + 1 }
          else { ws_cont_init = 0 }
        } else { ws_cont_init = 0 }
      }
    }

    local body = "["
    local first = 1
    local cont_prog = 1

    loop(cont_prog == 1) {
      // Inline skip_ws instead of calling me.skip_ws(src, i)
      if i < n {
        local ws_cont_1 = 1
        loop(ws_cont_1 == 1) {
          if i < n {
            local ch1 = src.substring(i, i + 1)
            if ch1 == " " || ch1 == "\n" || ch1 == "\r" || ch1 == "\t" { i = i + 1 }
            else { ws_cont_1 = 0 }
          } else { ws_cont_1 = 0 }
        }
      }

      if i >= src.length() {
        cont_prog = 0
      } else {
        local start_i = i
        local s = me.parse_stmt2(src, i)
        i = me.gpos_get()

        // Progress guard
        if i <= start_i {
          if i < src.length() { i = i + 1 }
          else { i = src.length() }
          me.gpos_set(i)
        }

        // consume optional semicolons
        local done2 = 0
        local guard2 = 0
        local max2 = 100000

        loop(done2 == 0) {
          if guard2 > max2 { done2 = 1 }
          else { guard2 = guard2 + 1 }

          local before2 = i
          // Inline skip_ws instead of calling me.skip_ws(src, i)
          if i < n {
            local ws_cont_2 = 1
            loop(ws_cont_2 == 1) {
              if i < n {
                local ch2 = src.substring(i, i + 1)
                if ch2 == " " || ch2 == "\n" || ch2 == "\r" || ch2 == "\t" { i = i + 1 }
                else { ws_cont_2 = 0 }
              } else { ws_cont_2 = 0 }
            }
          }

          if i < src.length() && src.substring(i, i+1) == ";" {
            i = i + 1
          } else {
            done2 = 1
          }

          if i == before2 { done2 = 1 }
        }

        if s.length() > 0 {
          if first == 1 {
            body = body + s
            first = 0
          } else {
            body = body + "," + s
          }
        }
      }
    }

    body = body + "]"
    return "{\"version\":0,\"kind\":\"Program\",\"body\":" + body + "}"
  }
}

static box ParserStub {
  main(args) {
    return 0
  }
}