#!/bin/bash
# SPDX-License-Identifier: LGPL-3.0-or-later
# See Notices.txt for copyright information
set -e

function fail()
{
    local error="$1"
    echo "error: $error" >&2
    exit 1
}

function fail_file()
{
    local file="$1" line="$2" error="$3"
    fail "$file:$((line + 1)): $error"
}

function check_file()
{
    local file="$1" regexes=("${@:2}")
    local lines
    mapfile -t lines < "$file"
    local line
    for line in "${!regexes[@]}"; do
        eval '[[ "${lines[i]}" =~ '"${regexes[i]}"' ]]' ||
            fail_file "$file" "$line" "doesn't match regex: ${regexes[i]}"
    done
}

POUND_HEADER=('^"# SPDX-License-Identifier: LGPL-3.0-or-later"$' '^"# See Notices.txt for copyright information"$')
SLASH_HEADER=('^"// SPDX-License-Identifier: LGPL-3.0-or-later"$' '^"// See Notices.txt for copyright information"$')
MD_HEADER=('^"<!--"$' '^"SPDX-License-Identifier: LGPL-3.0-or-later"$' '^"See Notices.txt for copyright information"$')
JSON_HEADER=('^"{"$' '^"    \"license_header\": ["$' '^"        \"SPDX-License-Identifier: LGPL-3.0-or-later\","$' '^"        \"See Notices.txt for copyright information\""')

function main()
{
    local IFS=$'\n'
    [[ -z "$(git status --porcelain)" ]] || fail "git repo is dirty"
    local file
    for file in $(git ls-tree --name-only --full-tree -r HEAD); do
        case "/$file" in
        /Cargo.lock)
            # generated file
            ;;
        */LICENSE.md|*/Notices.txt)
            # copyright file
            ;;
        /crates/fayalite/tests/ui/*.stderr)
            # file that can't contain copyright header
            ;;
        /.forgejo/workflows/*.yml|*/.gitignore|*.toml)
            check_file "$file" "${POUND_HEADER[@]}"
            ;;
        *.md)
            check_file "$file" "${MD_HEADER[@]}"
            ;;
        *.sh)
            check_file "$file" '^'\''#!'\' "${POUND_HEADER[@]}"
            ;;
        *.rs)
            check_file "$file" "${SLASH_HEADER[@]}"
            ;;
        *.json)
            check_file "$file" "${JSON_HEADER[@]}"
            ;;
        *)
            fail_file "$file" 0 "unimplemented file kind -- you need to add it to $0"
            ;;
        esac
    done
}

main