#!/bin/bash

# Create a changelog for an app after an upgrade from the file CHANGELOG.md.
#
# usage: ynh_app_changelog [--format=markdown/html/plain] [--output=changelog_file] --changelog=changelog_source]
# | arg: -f --format= - Format in which the changelog will be printed
#       markdown: Default format.
#       html:     Turn urls into html format.
#       plain:    Plain text changelog
# | arg: -o --output= - Output file for the changelog file (Default ./changelog)
# | arg: -c --changelog= - CHANGELOG.md source (Default ../CHANGELOG.md)
#
# The changelog is printed into the file ./changelog and ./changelog_lite
ynh_app_changelog () {
    # Declare an array to define the options of this helper.
    local legacy_args=foc
    declare -Ar args_array=( [f]=format= [o]=output= [c]=changelog= )
    local format
    local output
    local changelog
    # Manage arguments with getopts
    ynh_handle_getopts_args "$@"
    format=${format:-markdown}
    output=${output:-changelog}
    changelog=${changelog:-../CHANGELOG.md}

    local original_changelog="$changelog"
    local temp_changelog="changelog_temp"
    local final_changelog="$output"

    if [ ! -n "$original_changelog" ]
    then
        echo "No changelog available..." > "$final_changelog"
        echo "No changelog available..." > "${final_changelog}_lite"
        return 0
    fi

    local current_version=$(ynh_read_manifest --manifest="/etc/yunohost/apps/$YNH_APP_INSTANCE_NAME/manifest.json" --manifest_key="version")
    local update_version=$(ynh_read_manifest --manifest="../manifest.json" --manifest_key="version")

    # Get the line of the version to update to into the changelog
    local update_version_line=$(grep --max-count=1 --line-number "^## \[$update_version" "$original_changelog" | cut -d':' -f1)
    # If there's no entry for this version yet into the changelog
    # Get the first available version
    if [ -z "$update_version_line" ]
    then
        update_version_line=$(grep --max-count=1 --line-number "^##" "$original_changelog" | cut -d':' -f1)
    fi

    # Get the length of the complete changelog.
    local changelog_length=$(wc --lines "$original_changelog" | awk '{print $1}')
    # Cut the file before the version to update to.
    tail --lines=$(( $changelog_length - $update_version_line + 1 )) "$original_changelog" > "$temp_changelog"

    # Get the length of the troncated changelog.
    changelog_length=$(wc --lines "$temp_changelog" | awk '{print $1}')
    # Get the line of the current version into the changelog
    # Keep only the last line found
    local current_version_line=$(grep --line-number "^## \[$current_version" "$temp_changelog" | cut -d':' -f1 | tail --lines=1)
    # If there's no entry for this version into the changelog
    # Get the last available version
    if [ -z "$current_version_line" ]
    then
        current_version_line=$(grep --line-number "^##" "$original_changelog" | cut -d':' -f1 | tail --lines=1)
    fi
    # Cut the file before the current version.
    # Then grep the previous version into the changelog to get the line number of the previous version
    local previous_version_line=$(tail --lines=$(( $changelog_length - $current_version_line )) \
        "$temp_changelog" | grep --max-count=1 --line-number "^## " | cut -d':' -f1)
    # If there's no previous version into the changelog
    # Go until the end of the changelog
    if [ -z "$previous_version_line" ]
    then
        previous_version_line=$changelog_length
    fi

    # Cut the file after the previous version to keep only the changelog between the current version and the version to update to.
    head --lines=$(( $current_version_line + $previous_version_line - 1 )) "$temp_changelog" | tee "$final_changelog"

    if [ "$format" = "html" ]
    then
        # Replace markdown links by html links
        ynh_replace_string --match_string="\[\(.*\)\](\(.*\)))" --replace_string="<a href=\"\2\">\1</a>)" --target_file="$final_changelog"
        ynh_replace_string --match_string="\[\(.*\)\](\(.*\))" --replace_string="<a href=\"\2\">\1</a>" --target_file="$final_changelog"
    elif [ "$format" = "plain" ]
    then
        # Change title format.
        ynh_replace_string --match_string="^##.*\[\(.*\)\](\(.*\)) - \(.*\)$" --replace_string="## \1 (\3) - \2" --target_file="$final_changelog"
        # Change modifications lines format.
        ynh_replace_string --match_string="^\([-*]\).*\[\(.*\)\]\(.*\)" --replace_string="\1 \2 \3" --target_file="$final_changelog"
    fi
    # else markdown. As the file is already in markdown, nothing to do.

    # Keep only important changes into the changelog
    # Remove all minor changes
    sed '/^-/d' "$final_changelog" > "${final_changelog}_lite"
    # Remove all blank lines (to keep a clear workspace)
    sed --in-place '/^$/d' "${final_changelog}_lite"
    # Add a blank line at the end
    echo "" >> "${final_changelog}_lite"

    # Clean titles if there's no significative changes
    local line
    local previous_line=""
    while read line <&3
    do
        if [ -n "$previous_line" ]
        then
            # Remove the line if it's a title or a blank line, and the previous one was a title as well.
            if ( [ "${line:0:1}" = "#" ] || [ ${#line} -eq 0 ] ) && [ "${previous_line:0:1}" = "#" ]
            then
                ynh_replace_special_string --match_string="${previous_line//[/.}" --replace_string="" --target_file="${final_changelog}_lite"
            fi
        fi
        previous_line="$line"
    done 3< "${final_changelog}_lite"

    # Remove all blank lines again
    sed --in-place '/^$/d' "${final_changelog}_lite"

    # Restore changelog format with blank lines
    ynh_replace_string --match_string="^##.*" --replace_string="\n\n&\n" --target_file="${final_changelog}_lite"
    # Remove the 2 first blank lines
    sed --in-place '1,2d' "${final_changelog}_lite"
    # Add a blank line at the end
    echo "" >> "${final_changelog}_lite"

    # If changelog are empty, add an info
    if [ $(wc --words "$final_changelog" | awk '{print $1}') -eq 0 ]
    then
        echo "No changes from the changelog..." > "$final_changelog"
    fi
    if [ $(wc --words "${final_changelog}_lite" | awk '{print $1}') -eq 0 ]
    then
        echo "No significative changes from the changelog..." > "${final_changelog}_lite"
    fi
}