#! /bin/bash

target_module="$1"
target_fun_regex="$2"
shift 2
dirs=$@

find $dirs -type f -name '*.erl' -exec grep -Hn "\<$target_module\>:" '{}' \; \
| sed 's/%.*$//g' \
| awk \
    -F "${target_module}:" \
    -v target_module="$target_module" \
    -v target_fun_regex="$target_fun_regex" '
    $1 && $2 {
        caller_module_file = $1
        sub(":.*$", "", caller_module_file)

        called_function = $2
        sub("\\(.*$", "", called_function)

        if (called_function ~ /^[a-z][a-zA-Z_0-9]+$/) {
            if (called_function ~ target_fun_regex) {
                Calls[called_function]++
                Calls_from[caller_module_file, called_function]++
                Caller_modules[caller_module_file]++
            }
        } else {
            printf \
                "[WARN] skipped an invalid erlang function name. File: \"%s\", function: \"%s\", original line: \"%s\"\n", \
                caller_module_file, called_function, $0 \
                > "/dev/stderr"
        }
    }

    END {
        indent = "    "

        print "group-by-caller"
        for (caller_module_file in Caller_modules) {
            printf "%s%s\n", indent, caller_module_file;
            for (cf in Calls_from) {
                split(cf, call, SUBSEP);
                if (call[1] == caller_module_file)
                    printf "%s%s\n", indent indent, call[2] | "sort";
            }
            close("sort")
        }

        print "all"
        for (called_function in Calls)
            printf "%s%s\n", indent, called_function | "sort"
        close("sort")
    }'