#!/usr/bin/env bash
# Build the three books in every language they are kept in:  the user manual (docs/Manual.adoc,
# which ships inside the binary), the programming reference (docs/Reference.adoc), and the
# beginner's course (docs/Learn.adoc), in English and in each translation, a folder under docs/
# holding a locale.adoc (docs/fr, docs/it, docs/de, docs/es).  Produces .builddir/<Book>.html and
# .pdf for English and .builddir/<language>/<Book>.html and .pdf for each translation (a language's
# books sit together, so the links between them work), and then packs the two books that do not
# ship in the binary, with the lesson files and the license, into .builddir/Singe-Docs-v<version>.zip
# and .builddir/Singe-Docs-v<version>-<language>.zip, the optional documentation downloads.  The
# version comes from CMakeLists.txt.
#
#     ./build-docs.sh            the books as they ship
#     ./build-docs.sh preview    the same, with PREVIEW across every page, for proofreaders, all of it
#                                under .builddir/preview so neither a release nor the binary's own
#                                copies of the manual (rendered by CMake into .builddir) are touched;
#                                the downloads are named -preview so they cannot be mistaken for a
#                                release.
set -euo pipefail

here=$(cd "$(dirname "$0")" && pwd)
preview=
suffix=
if [[ "${1:-}" == "preview" ]]; then
    preview=1
    suffix=-preview
elif [[ -n "${1:-}" ]]; then
    echo "usage:  $0 [preview]" >&2
    exit 2
fi
books=(Manual Learn Reference)

# English is docs/ itself;  every other language is a folder of docs/ with its captions in it.
languages=(en)
for locale in "$here"/docs/*/locale.adoc; do
    languages+=("$(basename "$(dirname "$locale")")")
done

for language in "${languages[@]}"; do
    for book in "${books[@]}"; do
        doc=$here/docs/$book.adoc
        if [[ $language != en ]]; then
            doc=$here/docs/$language/$book.adoc
        fi
        if [[ ! -f $doc ]]; then
            echo "error: $doc not found" >&2
            exit 1
        fi
    done
done
for tool in asciidoctor asciidoctor-pdf zip; do
    if ! command -v "$tool" > /dev/null; then
        echo "error: $tool not found (gem install asciidoctor asciidoctor-pdf rouge)" >&2
        exit 1
    fi
done

# The version, from the four numbers of the project() line:  patch 1 means a beta and tweak says
# which, so 3.00.1.2 is the books' "3.00b2", exactly as the binary is named.
read -r major minor patch tweak <<< "$(sed -n 's/^project(singe2 VERSION \([0-9]*\)\.\([0-9]*\)\.\([0-9]*\)\.\([0-9]*\).*/\1 \2 \3 \4/p' "$here/CMakeLists.txt")"
if [[ $patch == 1 ]]; then
    version="${major}.${minor}b${tweak}"
else
    version="${major}.${minor}"
fi

# compress deflates the PDFs' streams, which takes most of them to under half their size.  The
# watermark, when asked for:  a page background for the PDFs, a head snippet for the HTML.
pdfOpts=(-a compress)
# The HTML pages carry their pictures inside them (data-uri), so a page is one file wherever it is
# copied and the download needs no images folder beside it.
htmlOpts=(-a data-uri)
out=$here/.builddir
if [[ -n $preview ]]; then
    pdfOpts+=(-a "page-background-image=image:$here/docs/images/preview.svg[fit=fill]")
    htmlOpts+=(-a docinfo=shared -a "docinfodir=$here/docs/preview")
    out=$here/.builddir/preview
fi

built=()
for language in "${languages[@]}"; do
    src=$here/docs
    dest=$out
    name=Singe-Docs-v$version
    if [[ $language != en ]]; then
        src=$here/docs/$language
        dest=$out/$language
        name=Singe-Docs-v$version-$language
    fi
    mkdir -p "$dest"
    for book in "${books[@]}"; do
        asciidoctor "${htmlOpts[@]}" -a revnumber="$version" "$src/$book.adoc" -o "$dest/$book.html"
        asciidoctor-pdf "${pdfOpts[@]}" -a revnumber="$version" "$src/$book.adoc" -o "$dest/$book.pdf"
        built+=("$dest/$book.html" "$dest/$book.pdf")
    done

    # The documentation download:  everything but the user manual, which the binary carries.  Built
    # in a staging folder so the zip has one top-level directory and no stray build files.
    stage=$out/$name$suffix
    rm -rf "$stage" "$stage.zip"
    mkdir -p "$stage/learn"
    cp "$dest/Reference.pdf" "$dest/Reference.html" "$dest/Learn.pdf" "$dest/Learn.html" "$stage/"
    cp -r "$here/docs/learn/." "$stage/learn/"
    cp "$here/COPYING" "$stage/"
    sed "s/@VERSION@/$version/" "$src/downloadReadme.txt" > "$stage/README.txt"
    (cd "$out" && zip -q -r "$name$suffix.zip" "$name$suffix")
    rm -rf "$stage"
    built+=("$stage.zip")
done

echo "built:"
ls -la "${built[@]}"