#!/bin/bash
# Comet Phase Guard — validates exit conditions before phase transitions
# Usage: comet-guard.sh <change-name> <current-phase> [--apply]
# Phases: open, design, build, verify, archive
# Exit 0 = all checks pass, exit 1 = blocked (reasons printed to stderr)
# shellcheck disable=SC2329  # Functions called indirectly via check() dispatch

set -euo pipefail

COMET_BASH="${COMET_BASH:-${BASH:-bash}}"

red() { echo -e "\033[31m$1\033[0m" >&2; }
green() { echo -e "\033[32m$1\033[0m" >&2; }
warn() { echo -e "\033[33m$1\033[0m" >&2; }

# Input validation - prevent path traversal
validate_change_name() {
  local name="$1"
  # Reject empty names
  if [ -z "$name" ]; then
    red "ERROR: Change name cannot be empty" >&2
    exit 1
  fi
  # Only allow alphanumeric, hyphens, and underscores
  if [[ ! "$name" =~ ^[a-zA-Z0-9_-]+$ ]]; then
    red "ERROR: Invalid change name: '$name'" >&2
    red "Valid characters: a-z, A-Z, 0-9, -, _" >&2
    exit 1
  fi
  # Reject path traversal attempts
  if [[ "$name" =~ \.\. ]]; then
    red "ERROR: Change name cannot contain '..' (path traversal not allowed)" >&2
    exit 1
  fi
}

if [ "${COMET_GUARD_SOURCE_ONLY:-0}" = "1" ]; then
  CHANGE="${CHANGE:-}"
  PHASE="${PHASE:-}"
  APPLY="${APPLY:-0}"
  SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]:-$0}")" && pwd -P)"
  CHANGE_DIR="${CHANGE_DIR:-}"
else
  validate_change_name "$1"

  CHANGE="$1"
  PHASE="$2"
  APPLY=0
  SCRIPT_DIR="$(cd "$(dirname "$0")" && pwd -P)"
  if [[ "${3:-}" == "--apply" ]]; then
    APPLY=1
  fi
  CHANGE_DIR="openspec/changes/$CHANGE"
  if [ "$PHASE" = "archive" ] && [ ! -d "$CHANGE_DIR" ] && [ -d "openspec/changes/archive/$CHANGE" ]; then
    CHANGE_DIR="openspec/changes/archive/$CHANGE"
  fi
fi

BLOCK=0
check() {
  local desc="$1"
  shift
  local output
  if output=$("$@" 2>&1); then
    green "  [PASS] $desc"
  else
    red "  [FAIL] $desc"
    if [ -n "$output" ]; then
      while IFS= read -r line; do
        red "    $line"
      done <<< "$output"
    fi
    BLOCK=1
  fi
}

# --- Helper functions ---

tasks_all_done() {
  local tasks="$CHANGE_DIR/tasks.md"
  if [ ! -f "$tasks" ]; then
    echo "tasks.md is missing at $tasks" >&2
    echo "Next: restore or create tasks.md for this change before leaving build." >&2
    return 1
  fi
  if ! grep -q '\- \[x\]' "$tasks"; then
    echo "tasks.md has no completed tasks." >&2
    echo "Next: complete implementation tasks and mark them with '- [x]'." >&2
    return 1
  fi
  if grep -q '\- \[ \]' "$tasks"; then
    echo "Unfinished tasks:" >&2
    grep -n '\- \[ \]' "$tasks" >&2 || true
    echo "Next: complete or explicitly remove unfinished tasks, then mark tasks.md with '- [x]'." >&2
    return 1
  fi
  return 0
}

tasks_has_any() {
  local tasks="$CHANGE_DIR/tasks.md"
  [ -f "$tasks" ] && grep -q '\- \[' "$tasks"
}

plan_tasks_all_done() {
  local plan
  plan=$(yaml_field_value "plan" 2>/dev/null || true)

  if [ -z "$plan" ] || [ "$plan" = "null" ]; then
    return 0
  fi
  if [ ! -f "$plan" ]; then
    echo "plan file is missing at $plan" >&2
    echo "Next: restore the Superpowers plan file or update .comet.yaml plan before leaving build." >&2
    return 1
  fi
  if grep -q '^[[:space:]]*- \[ \]' "$plan"; then
    echo "Unfinished Superpowers plan tasks:" >&2
    grep -n '^[[:space:]]*- \[ \]' "$plan" >&2 || true
    echo "Next: check off corresponding completed plan tasks, then commit the plan update." >&2
    return 1
  fi
  return 0
}

yaml_field_value() {
  local field="$1"
  local yaml="$CHANGE_DIR/.comet.yaml"
  if [ -f "$yaml" ]; then
    local value
    value=$(grep "^${field}:" "$yaml" 2>/dev/null | sed "s/^${field}: *//" || true)
    value=$(strip_inline_comment "$value")
    strip_wrapping_quotes "$value"
  fi
}

strip_inline_comment() {
  local value="$1"
  printf '%s\n' "$value" | awk -v squote="'" '
    {
      out = ""
      quote = ""
      for (i = 1; i <= length($0); i++) {
        c = substr($0, i, 1)
        if (quote == "") {
          if (c == "\"" || c == squote) {
            quote = c
          } else if (c == "#" && (i == 1 || substr($0, i - 1, 1) ~ /[[:space:]]/)) {
            sub(/[[:space:]]+$/, "", out)
            print out
            next
          }
        } else if (c == quote) {
          quote = ""
        }
        out = out c
      }
      print out
    }
  '
}

strip_wrapping_quotes() {
  local value="$1"
  case "$value" in
    \"*\")
      printf '%s\n' "${value:1:${#value}-2}"
      ;;
    \'*\')
      printf '%s\n' "${value:1:${#value}-2}"
      ;;
    *)
      printf '%s\n' "$value"
      ;;
  esac
}

project_config_value() {
  local field="$1"
  local value

  value=$(yaml_field_value "$field" 2>/dev/null || true)
  if [ -n "$value" ] && [ "$value" != "null" ]; then
    echo "$value"
    return 0
  fi

  for config in ".comet.yaml" "comet.yaml" ".comet.yml" "comet.yml"; do
    if [ -f "$config" ]; then
      value=$(grep "^${field}:" "$config" 2>/dev/null | sed "s/^${field}: *//" || true)
      value=$(strip_inline_comment "$value")
      value=$(strip_wrapping_quotes "$value")
      if [ -n "$value" ] && [ "$value" != "null" ]; then
        echo "$value"
        return 0
      fi
    fi
  done
}

file_nonempty() {
  [ -f "$1" ] && [ -s "$1" ]
}

is_windows_bash() {
  case "$(uname -s 2>/dev/null || true)" in
    MINGW*|MSYS*|CYGWIN*) return 0 ;;
    *) return 1 ;;
  esac
}

run_command_string() {
  local command="$1"
  if [ -z "$command" ]; then
    red "ERROR: build/verify command is empty" >&2
    return 1
  fi
  # Basic command injection guard: reject dangerous shell metacharacters
  # Quotes are allowed to support paths with spaces (e.g. Windows)
  if [[ "$command" =~ [\;\|\&\$\`] ]]; then
    red "ERROR: build/verify command contains shell metacharacters: $command" >&2
    red "Allowed: alphanumeric, spaces, hyphens, underscores, dots, colons, forward slashes, quotes" >&2
    return 1
  fi
  echo "+ $command" >&2
  "$COMET_BASH" -lc "$command"
}

hash_stream() {
  if command -v sha256sum >/dev/null 2>&1; then
    sha256sum | awk '{print $1}'
  elif command -v shasum >/dev/null 2>&1; then
    shasum -a 256 | awk '{print $1}'
  else
    echo "sha256sum or shasum is required" >&2
    return 1
  fi
}

hash_file() {
  local file="$1"
  if command -v sha256sum >/dev/null 2>&1; then
    sha256sum "$file" | awk '{print $1}'
  elif command -v shasum >/dev/null 2>&1; then
    shasum -a 256 "$file" | awk '{print $1}'
  else
    echo "sha256sum or shasum is required" >&2
    return 1
  fi
}

handoff_source_files() {
  printf '%s\n' "$CHANGE_DIR/proposal.md"
  printf '%s\n' "$CHANGE_DIR/design.md"
  printf '%s\n' "$CHANGE_DIR/tasks.md"
  if [ -d "$CHANGE_DIR/specs" ]; then
    find "$CHANGE_DIR/specs" -path '*/spec.md' -type f 2>/dev/null | sort
  fi
}

compute_handoff_hash() {
  local hash_input
  hash_input=$(handoff_source_files | while IFS= read -r file; do
    if [ -f "$file" ]; then
      printf 'path:%s\n' "$file"
      printf 'sha256:%s\n' "$(hash_file "$file")"
    fi
  done)
  printf '%s' "$hash_input" | hash_stream
}

preflight() {

  if [ ! -d "$CHANGE_DIR" ]; then
    red "FATAL: change directory not found: $CHANGE_DIR"
    exit 1
  fi
  if [ ! -f "$CHANGE_DIR/.comet.yaml" ]; then
    red "FATAL: .comet.yaml not found in $CHANGE_DIR"
    exit 1
  fi

  # Schema validation
  local validate_script
  validate_script="$SCRIPT_DIR/comet-yaml-validate.sh"
  if [ -f "$validate_script" ]; then
    if ! "$COMET_BASH" "$validate_script" "$CHANGE" 2>/dev/null; then
      "$COMET_BASH" "$validate_script" "$CHANGE" || true
      red "FATAL: .comet.yaml schema validation failed"
      exit 1
    fi
  fi
}

build_passes() {
  if [ "${COMET_SKIP_BUILD:-0}" = "1" ]; then
    return 0
  fi
  local configured_build
  configured_build=$(project_config_value "build_command" 2>/dev/null || true)
  if [ -n "$configured_build" ]; then
    run_command_string "$configured_build"
    return $?
  fi
  if [ -f "package.json" ] && grep -q '"build"' "package.json"; then
    npm run build
    return $?
  fi
  if [ -f "pom.xml" ]; then
    if [ -x "./mvnw" ]; then
      ./mvnw compile -q
    elif is_windows_bash && command -v mvn.cmd >/dev/null 2>&1; then
      mvn.cmd compile -q
    else
      mvn compile -q
    fi
    return $?
  fi
  if [ -f "Cargo.toml" ]; then
    cargo build
    return $?
  fi
  return 1
}

verification_command_passes() {
  if [ "${COMET_SKIP_BUILD:-0}" = "1" ]; then
    return 0
  fi
  local configured_verify
  configured_verify=$(project_config_value "verify_command" 2>/dev/null || true)
  if [ -n "$configured_verify" ]; then
    run_command_string "$configured_verify"
    return $?
  fi
  build_passes
}

isolation_selected() {
  local isolation
  isolation=$(yaml_field_value "isolation" 2>/dev/null || true)
  case "$isolation" in
    branch|worktree) return 0 ;;
    *)
      echo "isolation must be branch or worktree, got '${isolation:-null}'" >&2
      echo "Next: ask the user to choose branch or worktree, create the chosen isolation, then run:" >&2
      echo "  \"\$COMET_BASH\" \"\$COMET_STATE\" set $CHANGE isolation <branch|worktree>" >&2
      return 1
      ;;
  esac
}

build_mode_selected() {
  local build_mode
  build_mode=$(yaml_field_value "build_mode" 2>/dev/null || true)
  case "$build_mode" in
    subagent-driven-development|executing-plans|direct) return 0 ;;
    *)
      echo "build_mode must be selected before leaving build, got '${build_mode:-null}'" >&2
      echo "Next: ask the user to choose an execution mode, then run:" >&2
      echo "  \"\$COMET_BASH\" \"\$COMET_STATE\" set $CHANGE build_mode <subagent-driven-development|executing-plans>" >&2
      return 1
      ;;
  esac
}

build_mode_allowed_for_workflow() {
  local workflow build_mode direct_override
  workflow=$(yaml_field_value "workflow" 2>/dev/null || true)
  build_mode=$(yaml_field_value "build_mode" 2>/dev/null || true)
  direct_override=$(yaml_field_value "direct_override" 2>/dev/null || true)

  if [ "$build_mode" != "direct" ]; then
    return 0
  fi
  case "$workflow" in
    hotfix|tweak) return 0 ;;
    *)
      if [ "$direct_override" = "true" ]; then
        return 0
      fi
      echo "build_mode=direct is only allowed for hotfix/tweak unless direct_override: true is recorded" >&2
      echo "Next: choose executing-plans or subagent-driven-development, or stop and ask the user for an explicit direct override." >&2
      return 1
      ;;
  esac
}

subagent_dispatch_confirmed() {
  local build_mode subagent_dispatch
  build_mode=$(yaml_field_value "build_mode" 2>/dev/null || true)
  subagent_dispatch=$(yaml_field_value "subagent_dispatch" 2>/dev/null || true)

  if [ "$build_mode" != "subagent-driven-development" ]; then
    return 0
  fi

  if [ "$subagent_dispatch" = "confirmed" ]; then
    return 0
  fi

  echo "subagent_dispatch must be confirmed before using build_mode=subagent-driven-development" >&2
  echo "Next: confirm the current platform has a real background subagent/Task/multi-agent dispatcher, then run:" >&2
  echo "  \"\$COMET_BASH\" \"\$COMET_STATE\" set $CHANGE subagent_dispatch confirmed" >&2
  echo "Or ask the user to switch to executing-plans and run:" >&2
  echo "  \"\$COMET_BASH\" \"\$COMET_STATE\" set $CHANGE build_mode executing-plans" >&2
  return 1
}

tdd_mode_selected() {
  local workflow tdd_mode
  workflow=$(yaml_field_value "workflow" 2>/dev/null || true)
  tdd_mode=$(yaml_field_value "tdd_mode" 2>/dev/null || true)

  case "$workflow" in
    hotfix|tweak) return 0 ;;
  esac

  case "$tdd_mode" in
    tdd|direct) return 0 ;;
    *)
      echo "tdd_mode must be tdd or direct for full workflow, got '${tdd_mode:-null}'" >&2
      echo "Next: ask the user to choose TDD enforcement level, then run:" >&2
      echo "  \"\$COMET_BASH\" \"\$COMET_STATE\" set $CHANGE tdd_mode <tdd|direct>" >&2
      return 1
      ;;
  esac
}

review_mode_selected() {
  local workflow review_mode
  workflow=$(yaml_field_value "workflow" 2>/dev/null || true)
  review_mode=$(yaml_field_value "review_mode" 2>/dev/null || true)

  case "$workflow" in
    hotfix|tweak) return 0 ;;
  esac

  case "$review_mode" in
    off|standard|thorough) return 0 ;;
    *)
      echo "review_mode must be off, standard, or thorough before leaving build, got '${review_mode:-null}'" >&2
      echo "Next: ask the user to choose code review mode, then run:" >&2
      echo "  \"\$COMET_BASH\" \"\$COMET_STATE\" set $CHANGE review_mode <off|standard|thorough>" >&2
      return 1
      ;;
  esac
}

verify_result_is_pass() {
  local result
  result=$(yaml_field_value "verify_result" 2>/dev/null || true)
  [ "$result" = "pass" ]
}

verification_report_exists() {
  local report
  report=$(yaml_field_value "verification_report" 2>/dev/null || true)
  [ -n "$report" ] && [ "$report" != "null" ] && [ -f "$report" ]
}

branch_status_handled() {
  local status
  status=$(yaml_field_value "branch_status" 2>/dev/null || true)
  [ "$status" = "handled" ]
}

design_handoff_context_valid() {
  local context recorded_hash actual_hash markdown
  context=$(yaml_field_value "handoff_context" 2>/dev/null || true)
  recorded_hash=$(yaml_field_value "handoff_hash" 2>/dev/null || true)

  if [ -z "$context" ] || [ "$context" = "null" ]; then
    echo "handoff_context is missing from .comet.yaml" >&2
    echo "Next: run \"\$COMET_BASH\" \"\$COMET_HANDOFF\" $CHANGE design --write before invoking Superpowers." >&2
    return 1
  fi
  if [ ! -s "$context" ]; then
    echo "handoff_context does not point to a non-empty file: $context" >&2
    echo "Next: regenerate the design handoff with comet-handoff.sh." >&2
    return 1
  fi
  if [[ ! "$recorded_hash" =~ ^[a-f0-9]{64}$ ]]; then
    echo "handoff_hash is missing or invalid: ${recorded_hash:-null}" >&2
    echo "Next: regenerate the design handoff with comet-handoff.sh." >&2
    return 1
  fi

  actual_hash=$(compute_handoff_hash)
  if [ "$actual_hash" != "$recorded_hash" ]; then
    echo "OpenSpec artifacts changed after handoff was generated." >&2
    echo "Expected handoff_hash: $recorded_hash" >&2
    echo "Actual handoff_hash:   $actual_hash" >&2
    echo "Next: rerun comet-handoff.sh so Superpowers receives the current OpenSpec context." >&2
    return 1
  fi

  markdown="${context%.json}.md"
  if [ ! -s "$markdown" ]; then
    echo "design handoff markdown is missing or empty: $markdown" >&2
    echo "Next: regenerate the design handoff with comet-handoff.sh." >&2
    return 1
  fi
}

design_handoff_markdown_traceable() {
  local context markdown missing=0
  context=$(yaml_field_value "handoff_context" 2>/dev/null || true)
  if [ -z "$context" ] || [ "$context" = "null" ]; then
    echo "handoff_context is missing from .comet.yaml" >&2
    return 1
  fi
  markdown="${context%.json}.md"
  if [ ! -s "$markdown" ]; then
    echo "design handoff markdown is missing or empty: $markdown" >&2
    return 1
  fi
  grep -q '^Generated-by: comet-handoff\.sh$' "$markdown" || {
    echo "handoff markdown is missing Generated-by marker" >&2
    missing=1
  }
  grep -Eq '^- Mode: (compact|full|beta)$' "$markdown" || {
    echo "handoff markdown is missing Mode marker" >&2
    missing=1
  }
  handoff_source_files | while IFS= read -r file; do
    [ -f "$file" ] || continue
    if ! grep -q "^- Source: $file$" "$markdown"; then
      echo "handoff markdown is missing source reference: $file" >&2
      exit 2
    fi
    if ! grep -q "^- SHA256: $(hash_file "$file")$" "$markdown"; then
      echo "handoff markdown is missing current sha256 for: $file" >&2
      exit 2
    fi
  done || missing=1

  [ "$missing" -eq 0 ]
}

context_compression_mode() {
  local mode
  mode=$(yaml_field_value "context_compression" 2>/dev/null || true)
  printf '%s\n' "${mode:-off}"
}

beta_spec_json_structurally_valid() {
  local context missing=0
  if [ "$(context_compression_mode)" != "beta" ]; then
    return 0
  fi

  context=$(yaml_field_value "handoff_context" 2>/dev/null || true)
  if [ -z "$context" ] || [ "$context" = "null" ]; then
    echo "handoff_context is missing from .comet.yaml" >&2
    return 1
  fi
  if [ ! -s "$context" ]; then
    echo "spec-context.json is missing or empty: $context" >&2
    return 1
  fi

  # Validate required JSON fields
  grep -q '"change"' "$context" || { echo "spec-context.json missing 'change' field" >&2; return 1; }
  grep -q '"phase"' "$context" || { echo "spec-context.json missing 'phase' field" >&2; return 1; }
  grep -q '"mode": "beta"' "$context" || { echo "spec-context.json mode is not beta" >&2; return 1; }
  grep -q '"files"' "$context" || { echo "spec-context.json missing 'files' field" >&2; return 1; }
  grep -q '"context_hash"' "$context" || { echo "spec-context.json missing 'context_hash' field" >&2; return 1; }

  # Verify all source files are referenced in the JSON
  handoff_source_files | while IFS= read -r file; do
    [ -f "$file" ] || continue
    if ! grep -qF "$file" "$context"; then
      echo "spec-context.json missing source file reference: $file" >&2
      exit 2
    fi
  done || missing=1

  [ "$missing" -eq 0 ]
}

design_doc_frontmatter_has() {
  local design_doc="$1"
  local field="$2"
  local expected="$3"
  awk '
    {
      line = $0
      sub(/^\357\273\277/, "", line)
    }
    !in_fm && line == "---" { in_fm = 1; next }
    in_fm && line == "---" { exit }
    in_fm { print line }
  ' "$design_doc" | grep -Eq "^${field}: ['\"]?${expected}['\"]?[[:space:]]*$"
}

design_doc_links_current_change() {
  local design_doc
  design_doc=$(yaml_field_value "design_doc" 2>/dev/null || true)
  if [ -z "$design_doc" ] || [ "$design_doc" = "null" ] || [ ! -s "$design_doc" ]; then
    echo "design_doc must point to an existing Superpowers Design Doc before leaving design." >&2
    return 1
  fi
  design_doc_frontmatter_has "$design_doc" "comet_change" "$CHANGE"
}

design_doc_declares_technical_role() {
  local design_doc
  design_doc=$(yaml_field_value "design_doc" 2>/dev/null || true)
  [ -n "$design_doc" ] && [ "$design_doc" != "null" ] && [ -s "$design_doc" ] &&
    design_doc_frontmatter_has "$design_doc" "role" "technical-design"
}

design_doc_declares_canonical_spec() {
  local design_doc
  design_doc=$(yaml_field_value "design_doc" 2>/dev/null || true)
  [ -n "$design_doc" ] && [ "$design_doc" != "null" ] && [ -s "$design_doc" ] &&
    design_doc_frontmatter_has "$design_doc" "canonical_spec" "openspec"
}

archived_is_true() {
  local val
  val=$(yaml_field_value "archived" 2>/dev/null || true)
  [ "$val" = "true" ]
}

# --- Phase-specific checks ---

guard_open() {
  echo "=== Guard: open → next ===" >&2

  local workflow
  workflow=$(yaml_field_value "workflow" 2>/dev/null || true)

  check "proposal.md exists and non-empty" file_nonempty "$CHANGE_DIR/proposal.md"
  if [ "$workflow" = "full" ]; then
    check "design.md exists and non-empty" file_nonempty "$CHANGE_DIR/design.md"
  fi
  check "tasks.md exists and non-empty" file_nonempty "$CHANGE_DIR/tasks.md"
  check "tasks.md has at least one task" tasks_has_any
}

guard_design() {
  echo "=== Guard: design → build ===" >&2

  local design_doc workflow
  design_doc=$(yaml_field_value "design_doc" 2>/dev/null || true)
  workflow=$(yaml_field_value "workflow" 2>/dev/null || true)

  check "proposal.md exists" file_nonempty "$CHANGE_DIR/proposal.md"
  check "design.md exists" file_nonempty "$CHANGE_DIR/design.md"
  check "tasks.md exists" file_nonempty "$CHANGE_DIR/tasks.md"
  check "design handoff context exists" design_handoff_context_valid
  check "design handoff markdown is traceable" design_handoff_markdown_traceable
  if [ "$(context_compression_mode)" = "beta" ]; then
    check "beta spec-context.json is structurally valid" beta_spec_json_structurally_valid
  fi

  if [ "$workflow" = "full" ]; then
    # Full workflow: design_doc is REQUIRED
    check "design_doc is recorded for full workflow" design_doc_recorded
  fi

  if [ -n "$design_doc" ] && [ "$design_doc" != "null" ]; then
    check "Design Doc ($design_doc) exists" file_nonempty "$design_doc"
    check "Design Doc frontmatter links current change" design_doc_links_current_change
    check "Design Doc declares technical design role" design_doc_declares_technical_role
    check "Design Doc declares OpenSpec as canonical spec" design_doc_declares_canonical_spec
  elif [ "$workflow" != "full" ]; then
    warn "  [WARN] No design_doc recorded in .comet.yaml (optional for hotfix/tweak)"
  fi
}

design_doc_recorded() {
  local design_doc
  design_doc=$(yaml_field_value "design_doc" 2>/dev/null || true)
  if [ -n "$design_doc" ] && [ "$design_doc" != "null" ] && [ -f "$design_doc" ]; then
    return 0
  fi
  echo "design_doc must point to an existing Superpowers Design Doc for full workflow before leaving design." >&2
  echo "Next: create the Design Doc and run: \"\$COMET_BASH\" \"\$COMET_STATE\" set $CHANGE design_doc <path>" >&2
  return 1
}

guard_build() {
  echo "=== Guard: build → verify ===" >&2

  check "isolation selected" isolation_selected
  check "build_mode selected" build_mode_selected
  check "build_mode allowed for workflow" build_mode_allowed_for_workflow
  check "subagent dispatch confirmed" subagent_dispatch_confirmed
  check "tdd_mode selected" tdd_mode_selected
  check "review_mode selected" review_mode_selected
  check "tasks.md all tasks checked" tasks_all_done
  check "Superpowers plan all tasks checked" plan_tasks_all_done
  check "proposal.md exists" file_nonempty "$CHANGE_DIR/proposal.md"
  check "Build passes" build_passes
}

guard_verify() {
  echo "=== Guard: verify → archive ===" >&2

  check "tasks.md all tasks checked" tasks_all_done
  check "Build passes" verification_command_passes
  check "verification_report exists" verification_report_exists
  check "branch_status=handled" branch_status_handled
}

guard_archive() {
  echo "=== Guard: archive completeness ===" >&2

  check "archived is true" archived_is_true
  check "proposal.md exists" file_nonempty "$CHANGE_DIR/proposal.md"
  check "design.md exists" file_nonempty "$CHANGE_DIR/design.md"
  check "tasks.md all tasks checked" tasks_all_done
}

apply_state_update() {
  local state_sh="$SCRIPT_DIR/comet-state.sh"
  local p="$1"

  if [ -f "$state_sh" ]; then
    case "$p" in
      open)   "$COMET_BASH" "$state_sh" transition "$CHANGE" open-complete ;;
      design) "$COMET_BASH" "$state_sh" transition "$CHANGE" design-complete ;;
      build)  "$COMET_BASH" "$state_sh" transition "$CHANGE" build-complete ;;
      verify) "$COMET_BASH" "$state_sh" transition "$CHANGE" verify-pass ;;
    esac
  else
    red "FATAL: comet-state.sh not found; cannot apply state transition"
    exit 1
  fi
}

# --- Main ---

if [ "${COMET_GUARD_SOURCE_ONLY:-0}" = "1" ]; then
  return 0 2>/dev/null
  # shellcheck disable=SC2317  # unreachable if sourced; fallback for direct execution
  red "ERROR: COMET_GUARD_SOURCE_ONLY=1 is only for sourcing, not direct execution" >&2
  # shellcheck disable=SC2317
  exit 1
fi

case "$PHASE" in
  open)     preflight ; guard_open ;;
  design)   preflight ; guard_design ;;
  build)    preflight ; guard_build ;;
  verify)   preflight ; guard_verify ;;
  archive)  preflight ; guard_archive ;;
  *)
    red "Unknown phase: $PHASE"
    echo "Valid phases: open, design, build, verify, archive" >&2
    exit 1
    ;;
esac

if [ "$BLOCK" -eq 1 ]; then
  echo "" >&2
  red "BLOCKED — fix failing checks before proceeding to next phase"
  exit 1
else
  echo "" >&2
  green "ALL CHECKS PASSED — ready for next phase"
  if [ "$APPLY" -eq 1 ]; then
    apply_state_update "$PHASE"
    case "$PHASE" in
      open)
        new_phase=$(yaml_field_value "phase")
        green "  [APPLY] .comet.yaml updated: phase=$new_phase"
        ;;
      design) green "  [APPLY] .comet.yaml updated: phase=build" ;;
      build)  green "  [APPLY] .comet.yaml updated: phase=verify, verify_result=pending" ;;
      verify) green "  [APPLY] .comet.yaml updated: phase=archive, verify_result=pass" ;;
    esac
  fi
  exit 0
fi