src/main.cpp

/* Copyright 2025 Mike Becker. All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 * notice, this list of conditions and the following disclaimer.
 *
 * 2. Redistributions in binary form must reproduce the above copyright
 * notice, this list of conditions and the following disclaimer in the
 * documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
 * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#include "settings.h"
#include "repositories.h"
#include "process.h"
#include "heatmap.h"
#include "html.h"

#include <chrono>
#include <cstdlib>
#include <cstdio>
#include <cstring>
#include <cerrno>

namespace chrono = std::chrono;
using chrono::operator ""d;

static void print_help() {
    fputs(
        "Usage: fallusmeter [OPTION]... [PATH]...\n\n"
        "Options:\n"
        "   -h, --help             Print this help message\n"
        "   -d, --depth <num>      The search depth (default: 1, max: 255)\n"
        "   -n, --no-pull          Do not pull the repositories\n"
        "   -s, --separate         Output a separate heat map for each repository\n"
        "   -y, --year <year>      The year for which to create the heat map\n"
        "       --hg <path>        Path to hg binary (default: /usr/bin/hg)\n"
        "       --git <path>       Path to git binary (default: /usr/bin/git)\n\n"
        "Scans all specified paths recursively for Mercurial and Git repositories and\n"
        "creates a commit heat map for the specified \033[1myear\033[22m or the current year.\n"
        "By default, the recursion \033[1mdepth\033[22m is one, meaning that this tool assumes that\n"
        "each \033[1mpath\033[22m is either a repository or contains repositories as subdirectories.\n"
        "You can change the \033[1mdepth\033[22m to support other directory structures.\n\n"
        "When you do not specify \033[1m--no-pull\033[22m, this tool will execute the pull command\n"
        "(and for hg the update command) before retrieving the commit log, assuming\n"
        "to be on the default branch with \033[4mno uncommitted changes\033[24m. If pulling leads to\n"
        "an error, an error message is written to stderr and the process continues\n"
        "with the repository in its current state. This is also the case when pulling\n"
        "requires authorization.\n\n"
        "Afterwards, this tool prints an HTML page to stdout. A separate heap map is\n"
        "generated for each author showing commits across all repositories, unless the\n"
        "\033[1m--separate\033[22m option is specified in which case each repository is displayed with\n"
        "its own heat map.\n"
        , stderr);
}

static bool chk_arg(const char *arg, const char *opt1, const char *opt2) {
    return strcmp(arg, opt1) == 0 || (opt2 != nullptr && strcmp(arg, opt2) == 0);
}

template<typename T>
static bool parse_unsigned(const char *str, T *result, unsigned long max) {
    char *endptr;
    errno = 0;
    unsigned long d = strtoul(str, &endptr, 10);
    if (*endptr != '\0' || errno == ERANGE) return true;
    if (d < max) {
        *result = d;
        return false;
    } else {
        return true;
    }
}

static int parse_args(fm::settings &settings, int argc, char *argv[]) {
    for (int i = 1; i < argc; i++) {
        if (chk_arg(argv[i], "-h", "--help")) {
            print_help();
            return -1;
        } else if (chk_arg(argv[i], "-d", "--depth")) {
            if (i + 1 >= argc || parse_unsigned(argv[++i], &settings.depth, 256)) {
                fputs("missing or invalid depth\n", stderr);
                return -1;
            }
        } else if (chk_arg(argv[i], "-y", "--year")) {
            if (i + 1 >= argc || parse_unsigned(argv[++i], &settings.year, 9999)) {
                fputs("missing or invalid year\n", stderr);
                return -1;
            }
        } else if (chk_arg(argv[i], "-n", "--no-pull")) {
            settings.update_repos = false;
        } else if (chk_arg(argv[i], "-s", "--separate")) {
            settings.separate = true;
        } else if (chk_arg(argv[i], "--hg", nullptr)) {
            if (i + 1 < argc) {
                settings.hg.assign(argv[++i]);
            } else {
                fputs("--hg is expecting a path\n", stderr);
                return -1;
            }
        } else if (chk_arg(argv[i], "--git", nullptr)) {
            if (i + 1 < argc) {
                settings.git.assign(argv[++i]);
            } else {
                fputs("--git is expecting a path\n", stderr);
                return -1;
            }
        } else if (argv[i][0] == '-') {
            fprintf(stderr, "Unknown option: %s\n", argv[i]);
            return -1;
        } else {
            settings.paths.emplace_back(argv[i]);
        }
    }

    if (settings.paths.empty()) {
        settings.paths.emplace_back("./");
    }

    return 0;
}

int main(int argc, char *argv[]) {
    // parse settings
    fm::settings settings;
    if (parse_args(settings, argc, argv)) {
        return EXIT_FAILURE;
    }

    // check hg and git
    fm::process proc;
    proc.setbin(settings.hg);
    if (proc.exec({"--version"})) {
        fprintf(stderr, "Testing hg binary '%s' failed!\n", settings.hg.c_str());
        return EXIT_FAILURE;
    }
    proc.setbin(settings.git);
    if (proc.exec({"--version"})) {
        fprintf(stderr, "Testing git binary '%s' failed!\n", settings.git.c_str());
        return EXIT_FAILURE;
    }

    // scan for repos
    fm::repositories repos;
    for (auto &&path: settings.paths) {
        repos.scan(path, settings.depth);
    }

    // update repos, if not disabled
    if (settings.update_repos) {
        for (auto &&repo : repos.list()) {
            proc.chdir(repo.path);
            if (repo.type == fm::HG) {
                proc.setbin(settings.hg);
                if (proc.exec({"pull", "-y"})) {
                    fprintf(stderr, "Pulling repo '%s' failed!\nMaybe there is no remote?\n", repo.path.c_str());
                } else if (proc.exec({"update"})) {
                    fprintf(stderr, "Updating repo '%s' failed!\nMaybe there are local changes?\n", repo.path.c_str());
                }
            } else {
                proc.setbin(settings.git);
                if (proc.exec({"pull", "-q"})) {
                    fprintf(stderr, "Pulling repo '%s' failed!\nMaybe there is no remote or there are local changes?\n", repo.path.c_str());
                }
            }
        }
    }

    // determine our reporting range
    int year;
    if (settings.year == fm::settings_current_year) {
        year = static_cast<int>(chrono::year_month_day{chrono::floor<chrono::days>(chrono::system_clock::now())}.year());
    } else {
        year = settings.year;
    }
    chrono::year_month_day report_begin{chrono::year{year}, chrono::January, 1d};
    chrono::year_month_day report_end{chrono::year{year}, chrono::December, 31d};

    // read the commit logs
    fm::heatmap heatmap;
    for (auto &&repo : repos.list()) {
        if (settings.separate) {
            heatmap.set_repo(repo.path);
        }
        proc.chdir(repo.path);
        if (repo.type == fm::HG) {
            proc.setbin(settings.hg);
            if (proc.exec_log({"log",
                "--date", std::format("{0}-01-01 to {0}-12-31", year),
                "--template", "{author}#{date|shortdate}\n"})) {
                fprintf(stderr, "Reading commit log for repo '%s' failed!\n", repo.path.c_str());
                return EXIT_FAILURE;
            }
            heatmap.add(proc.output());
        } else {
            proc.setbin(settings.git);
            if (proc.exec_log({"log",
                "--since", std::format("{0}-01-01", year),
                "--until", std::format("{0}-12-31", year),
                "--format=tformat:%an <%ae>#%cs"})) {
                fprintf(stderr, "Reading commit log for repo '%s' failed!\n", repo.path.c_str());
                return EXIT_FAILURE;
            }
            heatmap.add(proc.output());
        }
    }

    html::open();
    for (const auto &[repo, authors] : heatmap.data()) {
        html::h1(repo);
        for (const auto &[author, entries] : authors) {
            html::h2(author);
            html::table_begin(year);

            // initialize counters
            unsigned column = 0, row = 0;

            // initialize first day (which must be a Monday, possibly the year before)
            chrono::sys_days day_to_check = chrono::January / chrono::Monday[1] / chrono::year{year};

            // remember the starting point
            auto start = day_to_check;

            // now add all entries for Monday, Tuesdays, etc. always starting back in january
            while (true) {
                html::row_begin(row);

                // check if we need to add blank cells
                while (day_to_check < report_begin) {
                    html::cell_out_of_range();
                    day_to_check += chrono::days{7};
                    column++;
                }

                while (day_to_check <= report_end) {
                    // get the entry from the heatmap
                    auto find_result = entries.find(day_to_check);
                    if (find_result == entries.end()) {
                        html::cell(day_to_check, 0);
                    } else {
                        html::cell(day_to_check, find_result->second);
                    }
                    // advance seven days and one column
                    day_to_check += chrono::days{7};
                    column++;
                }
                // fill remaining columns with blank cells
                for (unsigned i = column ; i < html::columns ; i++) {
                    html::cell_out_of_range();
                }

                // terminate the row
                html::row_end();

                // if we have seen all seven weekdays, that's it
                if (++row == 7) break;

                // otherwise, advance the starting point by one day, reset, and begin a new row
                start += chrono::days{1};
                day_to_check = start;
                column =0;
            }

            html::table_end();
        }
    }
    html::close();

    return EXIT_SUCCESS;
}