/*
 * Builtin "git commit"
 *
 * Copyright (c) 2007 Kristian Høgsberg <krh@redhat.com>
 * Based on git-commit.sh by Junio C Hamano and Linus Torvalds
 */

#include "cache.h"
#include "cache-tree.h"
#include "builtin.h"
#include "diff.h"
#include "diffcore.h"
#include "commit.h"
#include "revision.h"
#include "wt-status.h"
#include "run-command.h"
#include "refs.h"
#include "log-tree.h"
#include "strbuf.h"
#include "utf8.h"
#include "parse-options.h"

static const char * const builtin_commit_usage[] = {
        "git-commit [options] [--] <filepattern>...",
        NULL
};

static unsigned char head_sha1[20], merge_head_sha1[20];
static char *use_message_buffer;
static const char commit_editmsg[] = "COMMIT_EDITMSG";
static struct lock_file lock_file;

static char *logfile, *force_author, *template_file;
static char *edit_message, *use_message;
static int all, edit_flag, also, interactive, only, amend, signoff;
static int quiet, verbose, untracked_files, no_verify;

static int no_edit, initial_commit, in_merge;
const char *only_include_assumed;
struct strbuf message;

static int opt_parse_m(const struct option *opt, const char *arg, int unset)
{
        struct strbuf *buf = opt->value;
        if (unset)
                strbuf_setlen(buf, 0);
        else {
                strbuf_addstr(buf, arg);
                strbuf_addch(buf, '\n');
                strbuf_addch(buf, '\n');
        }
        return 0;
}

static struct option builtin_commit_options[] = {
        OPT__QUIET(&quiet),
        OPT__VERBOSE(&verbose),
        OPT_GROUP("Commit message options"),

        OPT_STRING('F', "file", &logfile, "FILE", "read log from file"),
        OPT_STRING(0, "author", &force_author, "AUTHOR", "override author for commit"),
        OPT_CALLBACK('m', "message", &message, "MESSAGE", "specify commit message", opt_parse_m),
        OPT_STRING('c', "reedit-message", &edit_message, "COMMIT", "reuse and edit message from specified commit "),
        OPT_STRING('C', "reuse-message", &use_message, "COMMIT", "reuse message from specified commit"),
        OPT_BOOLEAN('s', "signoff", &signoff, "add Signed-off-by: header"),
        OPT_STRING('t', "template", &template_file, "FILE", "use specified template file"),
        OPT_BOOLEAN('e', "edit", &edit_flag, "force edit of commit"),

        OPT_GROUP("Commit contents options"),
        OPT_BOOLEAN('a', "all", &all, "commit all changed files"),
        OPT_BOOLEAN('i', "include", &also, "add specified files to index for commit"),
        OPT_BOOLEAN(0, "interactive", &interactive, "interactively add files"),
        OPT_BOOLEAN('o', "only", &only, ""),
        OPT_BOOLEAN('n', "no-verify", &no_verify, "bypass pre-commit hook"),
        OPT_BOOLEAN(0, "amend", &amend, "amend previous commit"),
        OPT_BOOLEAN(0, "untracked-files", &untracked_files, "show all untracked files"),

        OPT_END()
};

static char *prepare_index(const char **files, const char *prefix)
{
        int fd;
        struct tree *tree;
        struct lock_file *next_index_lock;

        if (interactive) {
                interactive_add();
                return get_index_file();
        }

        fd = hold_locked_index(&lock_file, 1);
        if (read_cache() < 0)
                die("index file corrupt");

        if (all || also) {
                add_files_to_cache(verbose, also ? prefix : NULL, files);
                refresh_cache(REFRESH_QUIET);
                if (write_cache(fd, active_cache, active_nr) || close(fd))
                        die("unable to write new_index file");
                return lock_file.filename;
        }

        if (*files == NULL) {
                /* Commit index as-is. */
                rollback_lock_file(&lock_file);
                return get_index_file();
        }

        /* update the user index file */
        add_files_to_cache(verbose, prefix, files);
        refresh_cache(REFRESH_QUIET);
        if (write_cache(fd, active_cache, active_nr) || close(fd))
                die("unable to write new_index file");

        if (!initial_commit) {
                tree = parse_tree_indirect(head_sha1);
                if (!tree)
                        die("failed to unpack HEAD tree object");
                if (read_tree(tree, 0, NULL))
                        die("failed to read HEAD tree object");
        }

        /* Use a lock file to garbage collect the temporary index file. */
        next_index_lock = xmalloc(sizeof(*next_index_lock));
        fd = hold_lock_file_for_update(next_index_lock,
                                       git_path("next-index-%d", getpid()), 1);
        add_files_to_cache(verbose, prefix, files);
        refresh_cache(REFRESH_QUIET);
        if (write_cache(fd, active_cache, active_nr) || close(fd))
                die("unable to write new_index file");

        return next_index_lock->filename;
}

static int run_status(FILE *fp, const char *index_file, const char *prefix)
{
        struct wt_status s;

        wt_status_prepare(&s);
        s.prefix = prefix;

        if (amend) {
                s.amend = 1;
                s.reference = "HEAD^1";
        }
        s.verbose = verbose;
        s.untracked = untracked_files;
        s.index_file = index_file;
        s.fp = fp;

        wt_status_print(&s);

        return s.commitable;
}

static const char sign_off_header[] = "Signed-off-by: ";

static int prepare_log_message(const char *index_file, const char *prefix)
{
        struct stat statbuf;
        int commitable;
        struct strbuf sb;
        char *buffer;
        FILE *fp;

        strbuf_init(&sb, 0);
        if (message.len) {
                strbuf_addbuf(&sb, &message);
        } else if (logfile && !strcmp(logfile, "-")) {
                if (isatty(0))
                        fprintf(stderr, "(reading log message from standard input)\n");
                if (strbuf_read(&sb, 0, 0) < 0)
                        die("could not read log from standard input");
        } else if (logfile) {
                if (strbuf_read_file(&sb, logfile, 0) < 0)
                        die("could not read log file '%s': %s",
                            logfile, strerror(errno));
        } else if (use_message) {
                buffer = strstr(use_message_buffer, "\n\n");
                if (!buffer || buffer[2] == '\0')
                        die("commit has empty message");
                strbuf_add(&sb, buffer + 2, strlen(buffer + 2));
        } else if (!stat(git_path("MERGE_MSG"), &statbuf)) {
                if (strbuf_read_file(&sb, git_path("MERGE_MSG"), 0) < 0)
                        die("could not read MERGE_MSG: %s", strerror(errno));
        } else if (!stat(git_path("SQUASH_MSG"), &statbuf)) {
                if (strbuf_read_file(&sb, git_path("SQUASH_MSG"), 0) < 0)
                        die("could not read SQUASH_MSG: %s", strerror(errno));
        } else if (template_file && !stat(template_file, &statbuf)) {
                if (strbuf_read_file(&sb, template_file, 0) < 0)
                        die("could not read %s: %s",
                            template_file, strerror(errno));
        }

        fp = fopen(git_path(commit_editmsg), "w");
        if (fp == NULL)
                die("could not open %s\n", git_path(commit_editmsg));

        stripspace(&sb, 0);

        if (signoff) {
                struct strbuf sob;
                int i;

                strbuf_init(&sob, 0);
                strbuf_addstr(&sob, sign_off_header);
                strbuf_addstr(&sob, fmt_ident(getenv("GIT_COMMITTER_NAME"),
                                              getenv("GIT_COMMITTER_EMAIL"),
                                              "", 1));
                strbuf_addch(&sob, '\n');

                for (i = sb.len - 1; i > 0 && sb.buf[i - 1] != '\n'; i--)
                        ; /* do nothing */
                if (prefixcmp(sb.buf + i, sob.buf)) {
                        if (prefixcmp(sb.buf + i, sign_off_header))
                                strbuf_addch(&sb, '\n');
                        strbuf_addbuf(&sb, &sob);
                }
                strbuf_release(&sob);
        }

        if (fwrite(sb.buf, 1, sb.len, fp) < sb.len)
                die("could not write commit template: %s\n",
                    strerror(errno));

        strbuf_release(&sb);

        if (in_merge && !no_edit)
                fprintf(fp,
                        "#\n"
                        "# It looks like you may be committing a MERGE.\n"
                        "# If this is not correct, please remove the file\n"
                        "#      %s\n"
                        "# and try again.\n"
                        "#\n",
                        git_path("MERGE_HEAD"));

        fprintf(fp,
                "\n"
                "# Please enter the commit message for your changes.\n"
                "# (Comment lines starting with '#' will not be included)\n");
        if (only_include_assumed)
                fprintf(fp, "# %s\n", only_include_assumed);

        commitable = run_status(fp, index_file, prefix);

        fclose(fp);

        return commitable;
}

/*
 * Find out if the message starting at position 'start' in the strbuf
 * contains only whitespace and Signed-off-by lines.
 */
static int message_is_empty(struct strbuf *sb, int start)
{
        struct strbuf tmpl;
        const char *nl;
        int eol, i;

        /* See if the template is just a prefix of the message. */
        strbuf_init(&tmpl, 0);
        if (template_file && strbuf_read_file(&tmpl, template_file, 0) > 0) {
                stripspace(&tmpl, 1);
                if (start + tmpl.len <= sb->len &&
                    memcmp(tmpl.buf, sb->buf + start, tmpl.len) == 0)
                        start += tmpl.len;
        }
        strbuf_release(&tmpl);

        /* Check if the rest is just whitespace and Signed-of-by's. */
        for (i = start; i < sb->len; i++) {
                nl = memchr(sb->buf + i, '\n', sb->len - i);
                if (nl)
                        eol = nl - sb->buf;
                else
                        eol = sb->len;

                if (strlen(sign_off_header) <= eol - i &&
                    !prefixcmp(sb->buf + i, sign_off_header)) {
                        i = eol;
                        continue;
                }
                while (i < eol)
                        if (!isspace(sb->buf[i++]))
                                return 0;
        }

        return 1;
}

static void determine_author_info(struct strbuf *sb)
{
        char *name, *email, *date;

        name = getenv("GIT_AUTHOR_NAME");
        email = getenv("GIT_AUTHOR_EMAIL");
        date = getenv("GIT_AUTHOR_DATE");

        if (use_message) {
                const char *a, *lb, *rb, *eol;

                a = strstr(use_message_buffer, "\nauthor ");
                if (!a)
                        die("invalid commit: %s\n", use_message);

                lb = strstr(a + 8, " <");
                rb = strstr(a + 8, "> ");
                eol = strchr(a + 8, '\n');
                if (!lb || !rb || !eol)
                        die("invalid commit: %s\n", use_message);

                name = xstrndup(a + 8, lb - (a + 8));
                email = xstrndup(lb + 2, rb - (lb + 2));
                date = xstrndup(rb + 2, eol - (rb + 2));
        }

        if (force_author) {
                const char *lb = strstr(force_author, " <");
                const char *rb = strchr(force_author, '>');

                if (!lb || !rb)
                        die("malformed --author parameter\n");
                name = xstrndup(force_author, lb - force_author);
                email = xstrndup(lb + 2, rb - (lb + 2));
        }

        strbuf_addf(sb, "author %s\n", fmt_ident(name, email, date, 1));
}

static int parse_and_validate_options(int argc, const char *argv[])
{
        int f = 0;

        argc = parse_options(argc, argv, builtin_commit_options,
                             builtin_commit_usage, 0);

        if (logfile || message.len || use_message)
                no_edit = 1;
        if (edit_flag)
                no_edit = 0;

        if (get_sha1("HEAD", head_sha1))
                initial_commit = 1;

        if (!get_sha1("MERGE_HEAD", merge_head_sha1))
                in_merge = 1;

        /* Sanity check options */
        if (amend && initial_commit)
                die("You have nothing to amend.");
        if (amend && in_merge)
                die("You are in the middle of a merger -- cannot amend.");

        if (use_message)
                f++;
        if (edit_message)
                f++;
        if (logfile)
                f++;
        if (f > 1)
                die("Only one of -c/-C/-F can be used.");
        if (message.len && f > 0)
                die("Option -m cannot be combined with -c/-C/-F.");
        if (edit_message)
                use_message = edit_message;
        if (amend)
                use_message = "HEAD";
        if (use_message) {
                unsigned char sha1[20];
                static char utf8[] = "UTF-8";
                const char *out_enc;
                char *enc, *end;
                struct commit *commit;

                if (get_sha1(use_message, sha1))
                        die("could not lookup commit %s", use_message);
                commit = lookup_commit(sha1);
                if (!commit || parse_commit(commit))
                        die("could not parse commit %s", use_message);

                enc = strstr(commit->buffer, "\nencoding");
                if (enc) {
                        end = strchr(enc + 10, '\n');
                        enc = xstrndup(enc + 10, end - (enc + 10));
                } else {
                        enc = utf8;
                }
                out_enc = git_commit_encoding ? git_commit_encoding : utf8;

                if (strcmp(out_enc, enc))
                        use_message_buffer =
                                reencode_string(commit->buffer, out_enc, enc);

                /*
                 * If we failed to reencode the buffer, just copy it
                 * byte for byte so the user can try to fix it up.
                 * This also handles the case where input and output
                 * encodings are identical.
                 */
                if (use_message_buffer == NULL)
                        use_message_buffer = xstrdup(commit->buffer);
                if (enc != utf8)
                        free(enc);
        }

        if (!!also + !!only + !!all + !!interactive > 1)
                die("Only one of --include/--only/--all/--interactive can be used.");
        if (argc == 0 && (also || (only && !amend)))
                die("No paths with --include/--only does not make sense.");
        if (argc == 0 && only && amend)
                only_include_assumed = "Clever... amending the last one with dirty index.";
        if (argc > 0 && !also && !only) {
                only_include_assumed = "Explicit paths specified without -i nor -o; assuming --only paths...";
                also = 0;
        }

        if (all && argc > 0)
                die("Paths with -a does not make sense.");
        else if (interactive && argc > 0)
                die("Paths with --interactive does not make sense.");

        return argc;
}

int cmd_status(int argc, const char **argv, const char *prefix)
{
        const char *index_file;
        int commitable;

        git_config(git_status_config);

        argc = parse_and_validate_options(argc, argv);

        index_file = prepare_index(argv, prefix);

        commitable = run_status(stdout, index_file, prefix);

        rollback_lock_file(&lock_file);

        return commitable ? 0 : 1;
}

static int run_hook(const char *index_file, const char *name, const char *arg)
{
        struct child_process hook;
        const char *argv[3], *env[2];
        char index[PATH_MAX];

        argv[0] = git_path("hooks/%s", name);
        argv[1] = arg;
        argv[2] = NULL;
        snprintf(index, sizeof(index), "GIT_INDEX_FILE=%s", index_file);
        env[0] = index;
        env[1] = NULL;

        if (access(argv[0], X_OK) < 0)
                return 0;

        memset(&hook, 0, sizeof(hook));
        hook.argv = argv;
        hook.no_stdin = 1;
        hook.stdout_to_stderr = 1;
        hook.env = env;

        return run_command(&hook);
}

static void print_summary(const char *prefix, const unsigned char *sha1)
{
        struct rev_info rev;
        struct commit *commit;

        commit = lookup_commit(sha1);
        if (!commit)
                die("couldn't look up newly created commit\n");
        if (!commit || parse_commit(commit))
                die("could not parse newly created commit");

        init_revisions(&rev, prefix);
        setup_revisions(0, NULL, &rev, NULL);

        rev.abbrev = 0;
        rev.diff = 1;
        rev.diffopt.output_format =
                DIFF_FORMAT_SHORTSTAT | DIFF_FORMAT_SUMMARY;

        rev.verbose_header = 1;
        rev.show_root_diff = 1;
        rev.commit_format = get_commit_format("format:%h: %s");
        rev.always_show_header = 1;

        printf("Created %scommit ", initial_commit ? "initial " : "");

        log_tree_commit(&rev, commit);
        printf("\n");
}

int git_commit_config(const char *k, const char *v)
{
        if (!strcmp(k, "commit.template")) {
                template_file = xstrdup(v);
                return 0;
        }

        return git_status_config(k, v);
}

static const char commit_utf8_warn[] =
"Warning: commit message does not conform to UTF-8.\n"
"You may want to amend it after fixing the message, or set the config\n"
"variable i18n.commitencoding to the encoding your project uses.\n";

int cmd_commit(int argc, const char **argv, const char *prefix)
{
        int header_len;
        struct strbuf sb;
        const char *index_file, *reflog_msg;
        char *nl;
        unsigned char commit_sha1[20];
        struct ref_lock *ref_lock;

        git_config(git_commit_config);

        argc = parse_and_validate_options(argc, argv);

        index_file = prepare_index(argv, prefix);

        if (!no_verify && run_hook(index_file, "pre-commit", NULL))
                exit(1);

        if (!prepare_log_message(index_file, prefix) && !in_merge) {
                run_status(stdout, index_file, prefix);
                unlink(commit_editmsg);
                return 1;
        }

        strbuf_init(&sb, 0);

        /* Start building up the commit header */
        read_cache_from(index_file);
        active_cache_tree = cache_tree();
        if (cache_tree_update(active_cache_tree,
                              active_cache, active_nr, 0, 0) < 0)
                die("Error building trees");
        strbuf_addf(&sb, "tree %s\n",
                    sha1_to_hex(active_cache_tree->sha1));

        /* Determine parents */
        if (initial_commit) {
                reflog_msg = "commit (initial)";
        } else if (amend) {
                struct commit_list *c;
                struct commit *commit;

                reflog_msg = "commit (amend)";
                commit = lookup_commit(head_sha1);
                if (!commit || parse_commit(commit))
                        die("could not parse HEAD commit");

                for (c = commit->parents; c; c = c->next)
                        strbuf_addf(&sb, "parent %s\n",
                                      sha1_to_hex(c->item->object.sha1));
        } else if (in_merge) {
                struct strbuf m;
                FILE *fp;

                reflog_msg = "commit (merge)";
                strbuf_addf(&sb, "parent %s\n", sha1_to_hex(head_sha1));
                strbuf_init(&m, 0);
                fp = fopen(git_path("MERGE_HEAD"), "r");
                if (fp == NULL)
                        die("could not open %s for reading: %s",
                            git_path("MERGE_HEAD"), strerror(errno));
                while (strbuf_getline(&m, fp, '\n') != EOF)
                        strbuf_addf(&sb, "parent %s\n", m.buf);
                fclose(fp);
                strbuf_release(&m);
        } else {
                reflog_msg = "commit";
                strbuf_addf(&sb, "parent %s\n", sha1_to_hex(head_sha1));
        }

        determine_author_info(&sb);
        strbuf_addf(&sb, "committer %s\n", git_committer_info(1));
        if (!is_encoding_utf8(git_commit_encoding))
                strbuf_addf(&sb, "encoding %s\n", git_commit_encoding);
        strbuf_addch(&sb, '\n');

        /* Get the commit message and validate it */
        header_len = sb.len;
        if (!no_edit)
                launch_editor(git_path(commit_editmsg), &sb);
        else if (strbuf_read_file(&sb, git_path(commit_editmsg), 0) < 0)
                die("could not read commit message\n");
        if (run_hook(index_file, "commit-msg", commit_editmsg))
                exit(1);
        stripspace(&sb, 1);
        if (sb.len < header_len ||
            message_is_empty(&sb, header_len))
                die("* no commit message?  aborting commit.");
        strbuf_addch(&sb, '\0');
        if (is_encoding_utf8(git_commit_encoding) && !is_utf8(sb.buf))
                fprintf(stderr, commit_utf8_warn);

        if (write_sha1_file(sb.buf, sb.len - 1, commit_type, commit_sha1))
                die("failed to write commit object");

        ref_lock = lock_any_ref_for_update("HEAD",
                                           initial_commit ? NULL : head_sha1,
                                           0);

        nl = strchr(sb.buf + header_len, '\n');
        if (nl)
                strbuf_setlen(&sb, nl + 1 - sb.buf);
        else
                strbuf_addch(&sb, '\n');
        strbuf_remove(&sb, 0, header_len);
        strbuf_insert(&sb, 0, reflog_msg, strlen(reflog_msg));
        strbuf_insert(&sb, strlen(reflog_msg), ": ", 2);

        if (!ref_lock)
                die("cannot lock HEAD ref");
        if (write_ref_sha1(ref_lock, commit_sha1, sb.buf) < 0)
                die("cannot update HEAD ref");

        unlink(git_path("MERGE_HEAD"));
        unlink(git_path("MERGE_MSG"));

        if (lock_file.filename[0] && commit_locked_index(&lock_file))
                die("failed to write new index");

        rerere();

        run_hook(index_file, "post-commit", NULL);

        if (!quiet)
                print_summary(prefix, commit_sha1);

        return 0;
}