#!/usr/bin/env bash

# A simple script that uses ag <https://github.com/ggreer/the_silver_searcher> and perl
# to do a project-wide search/replace.
#
# Usage: ag-replace [pattern] [replace]

sanitize() {
    echo "$1" | sed -e "s_/_\\\/_g"
}

input=$(sanitize "$1")
replace=$(sanitize "$2")

RED=$(printf "\033[31m")
GREEN=$(printf "\033[32m")
NC=$(printf "\033[0m")

# Do a dry run for analysis
ag "$1" -s --nocolor --nogroup > /tmp/ag-repl
num=`cat /tmp/ag-repl | wc -l | sed -e "s/ //g"`
rm -rf /tmp/ag-repl
if [ "$num" -eq 0 ]; then
    echo "No results were found!"
    exit 1
fi

# Show the search/replace results
ag "$1" $3 -s --group --nocolor --nobreak \
    | perl -pe "s/(?<=.)$input/\033[4m$RED$replace$NC/g" \
    | perl -pe "s/^([^:]+)/$GREEN\$1$NC/g"

# Ask for confirmation
echo
echo -n "Apply $num changes? (y/n) "
read -n1 REPLY
echo

if [[ $REPLY =~ ^[Yy]$ ]]; then
    # Now actually do the search replace! This is destructive. No, no backups are made.
    # You better have read the earlier prompt!
    files=`ag "$1" $3 -s --nogroup --nocolor --files-with-matches`
    out=`echo "$files" | xargs perl -pi -e "s/$input/$replace/g"`
    echo "$files" | sed -e "s/^/  ✓ /g"

    echo
    echo "$num changes made!"
else
    echo "Aborted!"
    exit 2
fi