#!/usr/bin/env bash

set -euo pipefail

check_manifest_for_agpl () {
    local cargo_toml="$1"

    if grep -Eiq '(agpl|affero)' "$cargo_toml"; then
        echo "Error: $cargo_toml references an AGPL license. First-party crates must use LICENSE-GPL or LICENSE-APACHE."
        exit 1
    fi

    if grep -Eiq '^[[:space:]]*license-file[[:space:]]*=' "$cargo_toml"; then
        echo "Error: $cargo_toml uses license-file. First-party crates must declare LICENSE-GPL or LICENSE-APACHE via the license field and symlink."
        exit 1
    fi
}

check_no_agpl_license_file () {
    if [[ -e "LICENSE-AGPL" || -L "LICENSE-AGPL" ]]; then
        echo "Error: LICENSE-AGPL exists. First-party code must use LICENSE-GPL or LICENSE-APACHE."
        exit 1
    fi

    while IFS= read -r -d '' license_file; do
        if [[ -e "$license_file" || -L "$license_file" ]]; then
            echo "Error: $license_file exists. First-party crates must use LICENSE-GPL or LICENSE-APACHE."
            exit 1
        fi
    done < <(git ls-files -z -- "*/LICENSE-AGPL")
}

check_symlink_target () {
    local symlink_path="$1"
    local license_name="$2"

    local target=$(readlink "$symlink_path")

    local dir=$(dirname "$symlink_path")
    local depth=$(echo "$dir" | tr '/' '\n' | wc -l)
    local expected_prefix=""
    for ((i = 0; i < depth; i++)); do
        expected_prefix="../$expected_prefix"
    done
    local expected_target="${expected_prefix}${license_name}"

    if [[ "$target" != "$expected_target" ]]; then
        echo "Error: $symlink_path points to '$target' but should point to '$expected_target'"
        exit 1
    fi

    if [[ ! -e "$symlink_path" ]]; then
        echo "Error: $symlink_path is a broken symlink (target '$target' does not exist)"
        exit 1
    fi
}

check_license () {
    local dir="$1"
    local allowed_licenses=("LICENSE-GPL" "LICENSE-APACHE")

    for license in "${allowed_licenses[@]}"; do
        if [[ -L "$dir/$license" ]]; then
            check_symlink_target "$dir/$license" "$license"
            return 0
        elif [[ -e "$dir/$license" ]]; then
            echo "Error: $dir/$license exists but is not a symlink."
            exit 1
        fi
    done

    echo "Error: $dir does not contain a LICENSE-GPL or LICENSE-APACHE symlink"
    exit 1
}

check_no_agpl_license_file

git ls-files -z -- "Cargo.toml" "**/Cargo.toml" | while IFS= read -r -d '' cargo_toml; do
    check_manifest_for_agpl "$cargo_toml"

    if [[ "$cargo_toml" == */Cargo.toml ]]; then
        check_license "$(dirname "$cargo_toml")"
    fi
done

echo "check-licenses succeeded"