#!/usr/bin/env bash
# Two things the rustdoc build cannot see, checked here instead.
#
#   1. A ```rust fence in docs/ that is not compiled. Fences reach rustdoc
#      through include_str! and are compiled as doctests, but only if they are
#      tagged `rust` or left untagged. A fence tagged `text`, `ignore` or
#      `no_run` is prose wearing a code costume, and prose that claims to be
#      Rust rots silently.
#   2. A relative link between docs/ pages whose target file does not exist.
#      rustdoc resolves intra-doc links to Rust items, not to sibling markdown
#      files, so these are invisible to it.
set -euo pipefail

cd "$(dirname "$0")/.."

status=0

if [ -d docs ]; then
  while IFS= read -r -d '' page; do
    # 1. untested fences
    while IFS=: read -r lineno fence; do
      case "$fence" in
        '```ignore'*|'```no_run'*|'```rust,ignore'*|'```rust,no_run'*)
          echo "$page:$lineno: rust fence is not compiled: $fence" >&2
          status=1
          ;;
      esac
    done < <(grep -n '^```' "$page" || true)

    # 2. relative links to missing files
    while IFS= read -r target; do
      [ -z "$target" ] && continue
      case "$target" in
        http*|'#'*|mailto:*) continue ;;
      esac
      resolved="$(dirname "$page")/${target%%#*}"
      if [ ! -e "$resolved" ]; then
        echo "$page: link target does not exist: $target" >&2
        status=1
      fi
    done < <(grep -oE '\]\([^)]+\)' "$page" | sed -E 's/^\]\(//; s/\)$//' || true)
  done < <(find docs -name '*.md' -print0)
fi

if [ "$status" -eq 0 ]; then
  echo "doc-lint: ok"
fi
exit "$status"