//
// Cheddar changelog generator
// (c) cheddar-lang 2016-
// 
// Outputs information including:
//   - Change type
//   - Change author
//   - Change description
//   - Change hash
//

// Constants

const ITEM_LENGTH := 80;
const INDENT := ' - ';

// Objects
class Commit(
    public string: author,
    public string: email,
    public string: hash,
    public string: change
) {}

// Heavy lifting functions
func getlog(start, end) {
    return (
        String::IO.exec("git log %s..%s --format=%cn%n%ce%n%h%n%s" % start % end)
    ).lines.filter(line -> line).chunk(4).map(
        item -> Commit { item[0], item[1], item[2], item[3] }
    );
}

// Handle command-line args
let logoutput = cheddar.argc.len > 2 ? cheddar.argv[2] : "/dev/stdout";

// Get tags
let tags := (
    String::IO.exec( "git for-each-ref --sort=taggerdate --format '%(tag)'")
).lines.filter(i -> i).rev;

let output := IO.open(logoutput, "a");

for (let i = 0; i < tags.len - 1; i += 1) {
    let former = tags[i + 1];
    let latter = tags[i];

    let logItems = getlog(former, latter);
    let longestAuthor = logItems.reduce((a, b) -> a.author.len > b.author.len ? a : b, 0).author.len;

    output.write(
        (former + " -> " + latter).center(80) + "\n"
    );

    output.write( "=" * 80 + "\n");

    // Handle commits
    let commits = [
        "other": []
    ];

    let categories = [ ];
    for (item in logItems) {
        let details = item.change.exec(/^(.+?) \[(.+?)\]: (.+)/g);

        let name;
        let value;

        if (details['1']) {
            name = details['1'].lower;
            item.change = "%s: %s" % details['2'] % details['3'];
            if (commits[name]) {
                commits[name].push(item);
            } else {
                categories.push(name);
                commits[name] = [ item ];
            }
        } else {
            // Unstandard commit
            commits["other"].push(item);

            if (!( categories has "other" )) {
                categories.push("other");
            }
        }
    }

    for (category in categories.sorted) {
        output.write(category + ":\n");

        for (item in commits[category]) {
            output.write(INDENT + IO.sprintf("%-*s", longestAuthor, item.author) + " (%s) %s\n" % item.hash % item.change);
        }
    }

    output.write("\n\n");
}

output.close();