/*
 * Builtin "git notes"
 *
 * Copyright (c) 2010 Johan Herland <johan@herland.net>
 *
 * Based on git-notes.sh by Johannes Schindelin,
 * and builtin-tag.c by Kristian Høgsberg and Carlos Rica.
 */

#include "cache.h"
#include "builtin.h"
#include "notes.h"
#include "blob.h"
#include "commit.h"
#include "refs.h"
#include "exec_cmd.h"
#include "run-command.h"
#include "parse-options.h"
#include "string-list.h"

static const char * const git_notes_usage[] = {
        "git notes [list [<object>]]",
        "git notes add [-f] [-m <msg> | -F <file> | (-c | -C) <object>] [<object>]",
        "git notes copy [-f] <from-object> <to-object>",
        "git notes append [-m <msg> | -F <file> | (-c | -C) <object>] [<object>]",
        "git notes edit [<object>]",
        "git notes show [<object>]",
        "git notes remove [<object>]",
        "git notes prune",
        NULL
};

static const char note_template[] =
        "\n"
        "#\n"
        "# Write/edit the notes for the following object:\n"
        "#\n";

struct msg_arg {
        int given;
        int use_editor;
        struct strbuf buf;
};

static int list_each_note(const unsigned char *object_sha1,
                const unsigned char *note_sha1, char *note_path,
                void *cb_data)
{
        printf("%s %s\n", sha1_to_hex(note_sha1), sha1_to_hex(object_sha1));
        return 0;
}

static void write_note_data(int fd, const unsigned char *sha1)
{
        unsigned long size;
        enum object_type type;
        char *buf = read_sha1_file(sha1, &type, &size);
        if (buf) {
                if (size)
                        write_or_die(fd, buf, size);
                free(buf);
        }
}

static void write_commented_object(int fd, const unsigned char *object)
{
        const char *show_args[5] =
                {"show", "--stat", "--no-notes", sha1_to_hex(object), NULL};
        struct child_process show;
        struct strbuf buf = STRBUF_INIT;
        FILE *show_out;

        /* Invoke "git show --stat --no-notes $object" */
        memset(&show, 0, sizeof(show));
        show.argv = show_args;
        show.no_stdin = 1;
        show.out = -1;
        show.err = 0;
        show.git_cmd = 1;
        if (start_command(&show))
                die("unable to start 'show' for object '%s'",
                    sha1_to_hex(object));

        /* Open the output as FILE* so strbuf_getline() can be used. */
        show_out = xfdopen(show.out, "r");
        if (show_out == NULL)
                die_errno("can't fdopen 'show' output fd");

        /* Prepend "# " to each output line and write result to 'fd' */
        while (strbuf_getline(&buf, show_out, '\n') != EOF) {
                write_or_die(fd, "# ", 2);
                write_or_die(fd, buf.buf, buf.len);
                write_or_die(fd, "\n", 1);
        }
        strbuf_release(&buf);
        if (fclose(show_out))
                die_errno("failed to close pipe to 'show' for object '%s'",
                          sha1_to_hex(object));
        if (finish_command(&show))
                die("failed to finish 'show' for object '%s'",
                    sha1_to_hex(object));
}

static void create_note(const unsigned char *object, struct msg_arg *msg,
                        int append_only, const unsigned char *prev,
                        unsigned char *result)
{
        char *path = NULL;

        if (msg->use_editor || !msg->given) {
                int fd;

                /* write the template message before editing: */
                path = git_pathdup("NOTES_EDITMSG");
                fd = open(path, O_CREAT | O_TRUNC | O_WRONLY, 0600);
                if (fd < 0)
                        die_errno("could not create file '%s'", path);

                if (msg->given)
                        write_or_die(fd, msg->buf.buf, msg->buf.len);
                else if (prev && !append_only)
                        write_note_data(fd, prev);
                write_or_die(fd, note_template, strlen(note_template));

                write_commented_object(fd, object);

                close(fd);
                strbuf_reset(&(msg->buf));

                if (launch_editor(path, &(msg->buf), NULL)) {
                        die("Please supply the note contents using either -m" \
                            " or -F option");
                }
                stripspace(&(msg->buf), 1);
        }

        if (prev && append_only) {
                /* Append buf to previous note contents */
                unsigned long size;
                enum object_type type;
                char *prev_buf = read_sha1_file(prev, &type, &size);

                strbuf_grow(&(msg->buf), size + 1);
                if (msg->buf.len && prev_buf && size)
                        strbuf_insert(&(msg->buf), 0, "\n", 1);
                if (prev_buf && size)
                        strbuf_insert(&(msg->buf), 0, prev_buf, size);
                free(prev_buf);
        }

        if (!msg->buf.len) {
                fprintf(stderr, "Removing note for object %s\n",
                        sha1_to_hex(object));
                hashclr(result);
        } else {
                if (write_sha1_file(msg->buf.buf, msg->buf.len, blob_type, result)) {
                        error("unable to write note object");
                        if (path)
                                error("The note contents has been left in %s",
                                      path);
                        exit(128);
                }
        }

        if (path) {
                unlink_or_warn(path);
                free(path);
        }
}

static int parse_msg_arg(const struct option *opt, const char *arg, int unset)
{
        struct msg_arg *msg = opt->value;

        if (!arg)
                return -1;

        strbuf_grow(&(msg->buf), strlen(arg) + 2);
        if (msg->buf.len)
                strbuf_addstr(&(msg->buf), "\n");
        strbuf_addstr(&(msg->buf), arg);
        stripspace(&(msg->buf), 0);

        msg->given = 1;
        return 0;
}

static int parse_file_arg(const struct option *opt, const char *arg, int unset)
{
        struct msg_arg *msg = opt->value;

        if (!arg)
                return -1;

        if (msg->buf.len)
                strbuf_addstr(&(msg->buf), "\n");
        if (!strcmp(arg, "-")) {
                if (strbuf_read(&(msg->buf), 0, 1024) < 0)
                        die_errno("cannot read '%s'", arg);
        } else if (strbuf_read_file(&(msg->buf), arg, 1024) < 0)
                die_errno("could not open or read '%s'", arg);
        stripspace(&(msg->buf), 0);

        msg->given = 1;
        return 0;
}

static int parse_reuse_arg(const struct option *opt, const char *arg, int unset)
{
        struct msg_arg *msg = opt->value;
        char *buf;
        unsigned char object[20];
        enum object_type type;
        unsigned long len;

        if (!arg)
                return -1;

        if (msg->buf.len)
                strbuf_addstr(&(msg->buf), "\n");

        if (get_sha1(arg, object))
                die("Failed to resolve '%s' as a valid ref.", arg);
        if (!(buf = read_sha1_file(object, &type, &len)) || !len) {
                free(buf);
                die("Failed to read object '%s'.", arg);;
        }
        strbuf_add(&(msg->buf), buf, len);
        free(buf);

        msg->given = 1;
        return 0;
}

static int parse_reedit_arg(const struct option *opt, const char *arg, int unset)
{
        struct msg_arg *msg = opt->value;
        msg->use_editor = 1;
        return parse_reuse_arg(opt, arg, unset);
}

int commit_notes(struct notes_tree *t, const char *msg)
{
        struct commit_list *parent;
        unsigned char tree_sha1[20], prev_commit[20], new_commit[20];
        struct strbuf buf = STRBUF_INIT;

        if (!t)
                t = &default_notes_tree;
        if (!t->initialized || !t->ref || !*t->ref)
                die("Cannot commit uninitialized/unreferenced notes tree");
        if (!t->dirty)
                return 0; /* don't have to commit an unchanged tree */

        /* Prepare commit message and reflog message */
        strbuf_addstr(&buf, "notes: "); /* commit message starts at index 7 */
        strbuf_addstr(&buf, msg);
        if (buf.buf[buf.len - 1] != '\n')
                strbuf_addch(&buf, '\n'); /* Make sure msg ends with newline */

        /* Convert notes tree to tree object */
        if (write_notes_tree(t, tree_sha1))
                die("Failed to write current notes tree to database");

        /* Create new commit for the tree object */
        if (!read_ref(t->ref, prev_commit)) { /* retrieve parent commit */
                parent = xmalloc(sizeof(*parent));
                parent->item = lookup_commit(prev_commit);
                parent->next = NULL;
        } else {
                hashclr(prev_commit);
                parent = NULL;
        }
        if (commit_tree(buf.buf + 7, tree_sha1, parent, new_commit, NULL))
                die("Failed to commit notes tree to database");

        /* Update notes ref with new commit */
        update_ref(buf.buf, t->ref, new_commit, prev_commit, 0, DIE_ON_ERR);

        strbuf_release(&buf);
        return 0;
}


combine_notes_fn *parse_combine_notes_fn(const char *v)
{
        if (!strcasecmp(v, "overwrite"))
                return combine_notes_overwrite;
        else if (!strcasecmp(v, "ignore"))
                return combine_notes_ignore;
        else if (!strcasecmp(v, "concatenate"))
                return combine_notes_concatenate;
        else
                return NULL;
}

static int notes_rewrite_config(const char *k, const char *v, void *cb)
{
        struct notes_rewrite_cfg *c = cb;
        if (!prefixcmp(k, "notes.rewrite.") && !strcmp(k+14, c->cmd)) {
                c->enabled = git_config_bool(k, v);
                return 0;
        } else if (!c->mode_from_env && !strcmp(k, "notes.rewritemode")) {
                if (!v)
                        config_error_nonbool(k);
                c->combine = parse_combine_notes_fn(v);
                if (!c->combine) {
                        error("Bad notes.rewriteMode value: '%s'", v);
                        return 1;
                }
                return 0;
        } else if (!c->refs_from_env && !strcmp(k, "notes.rewriteref")) {
                /* note that a refs/ prefix is implied in the
                 * underlying for_each_glob_ref */
                if (!prefixcmp(v, "refs/notes/"))
                        string_list_add_refs_by_glob(c->refs, v);
                else
                        warning("Refusing to rewrite notes in %s"
                                " (outside of refs/notes/)", v);
                return 0;
        }

        return 0;
}


struct notes_rewrite_cfg *init_copy_notes_for_rewrite(const char *cmd)
{
        struct notes_rewrite_cfg *c = xmalloc(sizeof(struct notes_rewrite_cfg));
        const char *rewrite_mode_env = getenv(GIT_NOTES_REWRITE_MODE_ENVIRONMENT);
        const char *rewrite_refs_env = getenv(GIT_NOTES_REWRITE_REF_ENVIRONMENT);
        c->cmd = cmd;
        c->enabled = 1;
        c->combine = combine_notes_concatenate;
        c->refs = xcalloc(1, sizeof(struct string_list));
        c->refs->strdup_strings = 1;
        c->refs_from_env = 0;
        c->mode_from_env = 0;
        if (rewrite_mode_env) {
                c->mode_from_env = 1;
                c->combine = parse_combine_notes_fn(rewrite_mode_env);
                if (!c->combine)
                        error("Bad " GIT_NOTES_REWRITE_MODE_ENVIRONMENT
                              " value: '%s'", rewrite_mode_env);
        }
        if (rewrite_refs_env) {
                c->refs_from_env = 1;
                string_list_add_refs_from_colon_sep(c->refs, rewrite_refs_env);
        }
        git_config(notes_rewrite_config, c);
        if (!c->enabled || !c->refs->nr) {
                string_list_clear(c->refs, 0);
                free(c->refs);
                free(c);
                return NULL;
        }
        c->trees = load_notes_trees(c->refs);
        string_list_clear(c->refs, 0);
        free(c->refs);
        return c;
}

int copy_note_for_rewrite(struct notes_rewrite_cfg *c,
                          const unsigned char *from_obj, const unsigned char *to_obj)
{
        int ret = 0;
        int i;
        for (i = 0; c->trees[i]; i++)
                ret = copy_note(c->trees[i], from_obj, to_obj, 1, c->combine) || ret;
        return ret;
}

void finish_copy_notes_for_rewrite(struct notes_rewrite_cfg *c)
{
        int i;
        for (i = 0; c->trees[i]; i++) {
                commit_notes(c->trees[i], "Notes added by 'git notes copy'");
                free_notes(c->trees[i]);
        }
        free(c->trees);
        free(c);
}

int notes_copy_from_stdin(int force, const char *rewrite_cmd)
{
        struct strbuf buf = STRBUF_INIT;
        struct notes_rewrite_cfg *c = NULL;
        struct notes_tree *t;
        int ret = 0;

        if (rewrite_cmd) {
                c = init_copy_notes_for_rewrite(rewrite_cmd);
                if (!c)
                        return 0;
        } else {
                init_notes(NULL, NULL, NULL, 0);
                t = &default_notes_tree;
        }

        while (strbuf_getline(&buf, stdin, '\n') != EOF) {
                unsigned char from_obj[20], to_obj[20];
                struct strbuf **split;
                int err;

                split = strbuf_split(&buf, ' ');
                if (!split[0] || !split[1])
                        die("Malformed input line: '%s'.", buf.buf);
                strbuf_rtrim(split[0]);
                strbuf_rtrim(split[1]);
                if (get_sha1(split[0]->buf, from_obj))
                        die("Failed to resolve '%s' as a valid ref.", split[0]->buf);
                if (get_sha1(split[1]->buf, to_obj))
                        die("Failed to resolve '%s' as a valid ref.", split[1]->buf);

                if (rewrite_cmd)
                        err = copy_note_for_rewrite(c, from_obj, to_obj);
                else
                        err = copy_note(t, from_obj, to_obj, force,
                                        combine_notes_overwrite);

                if (err) {
                        error("Failed to copy notes from '%s' to '%s'",
                              split[0]->buf, split[1]->buf);
                        ret = 1;
                }

                strbuf_list_free(split);
        }

        if (!rewrite_cmd) {
                commit_notes(t, "Notes added by 'git notes copy'");
                free_notes(t);
        } else {
                finish_copy_notes_for_rewrite(c);
        }
        return ret;
}

int cmd_notes(int argc, const char **argv, const char *prefix)
{
        struct notes_tree *t;
        unsigned char object[20], from_obj[20], new_note[20];
        const unsigned char *note;
        const char *object_ref;
        char logmsg[100];

        int list = 0, add = 0, copy = 0, append = 0, edit = 0, show = 0,
            remove = 0, prune = 0, force = 0, from_stdin = 0;
        int given_object = 0, i = 1, retval = 0;
        struct msg_arg msg = { 0, 0, STRBUF_INIT };
        const char *rewrite_cmd = NULL;
        const char *override_notes_ref = NULL;
        struct option options[] = {
                OPT_GROUP("Notes options"),
                OPT_CALLBACK('m', "message", &msg, "MSG",
                             "note contents as a string", parse_msg_arg),
                OPT_CALLBACK('F', "file", &msg, "FILE",
                             "note contents in a file", parse_file_arg),
                OPT_CALLBACK('c', "reedit-message", &msg, "OBJECT",
                           "reuse and edit specified note object", parse_reedit_arg),
                OPT_CALLBACK('C', "reuse-message", &msg, "OBJECT",
                           "reuse specified note object", parse_reuse_arg),
                OPT_BOOLEAN('f', "force", &force, "replace existing notes"),
                OPT_BOOLEAN(0, "stdin", &from_stdin, "read objects from stdin"),
                OPT_STRING(0, "ref", &override_notes_ref, "notes_ref",
                           "use notes from <notes_ref>"),
                OPT_STRING(0, "for-rewrite", &rewrite_cmd, "command",
                           "load rewriting config for <command> (implies --stdin)"),
                OPT_END()
        };

        git_config(git_default_config, NULL);

        argc = parse_options(argc, argv, prefix, options, git_notes_usage, 0);

        if (override_notes_ref) {
                struct strbuf sb = STRBUF_INIT;
                if (!prefixcmp(override_notes_ref, "refs/notes/"))
                        /* we're happy */;
                else if (!prefixcmp(override_notes_ref, "notes/"))
                        strbuf_addstr(&sb, "refs/");
                else
                        strbuf_addstr(&sb, "refs/notes/");
                strbuf_addstr(&sb, override_notes_ref);
                setenv("GIT_NOTES_REF", sb.buf, 1);
                strbuf_release(&sb);
        }

        if (argc && !strcmp(argv[0], "list"))
                list = 1;
        else if (argc && !strcmp(argv[0], "add"))
                add = 1;
        else if (argc && !strcmp(argv[0], "copy"))
                copy = 1;
        else if (argc && !strcmp(argv[0], "append"))
                append = 1;
        else if (argc && !strcmp(argv[0], "edit"))
                edit = 1;
        else if (argc && !strcmp(argv[0], "show"))
                show = 1;
        else if (argc && !strcmp(argv[0], "remove"))
                remove = 1;
        else if (argc && !strcmp(argv[0], "prune"))
                prune = 1;
        else if (!argc) {
                list = 1; /* Default to 'list' if no other subcommand given */
                i = 0;
        }

        if (list + add + copy + append + edit + show + remove + prune != 1)
                usage_with_options(git_notes_usage, options);

        if (msg.given && !(add || append || edit)) {
                error("cannot use -m/-F/-c/-C options with %s subcommand.",
                      argv[0]);
                usage_with_options(git_notes_usage, options);
        }

        if (msg.given && edit) {
                fprintf(stderr, "The -m/-F/-c/-C options have been deprecated "
                        "for the 'edit' subcommand.\n"
                        "Please use 'git notes add -f -m/-F/-c/-C' instead.\n");
        }

        if (force && !(add || copy)) {
                error("cannot use -f option with %s subcommand.", argv[0]);
                usage_with_options(git_notes_usage, options);
        }

        if (!copy && rewrite_cmd) {
                error("cannot use --for-rewrite with %s subcommand.", argv[0]);
                usage_with_options(git_notes_usage, options);
        }
        if (!copy && from_stdin) {
                error("cannot use --stdin with %s subcommand.", argv[0]);
                usage_with_options(git_notes_usage, options);
        }

        if (copy) {
                const char *from_ref;
                if (from_stdin || rewrite_cmd) {
                        if (argc > 1) {
                                error("too many parameters");
                                usage_with_options(git_notes_usage, options);
                        } else {
                                return notes_copy_from_stdin(force, rewrite_cmd);
                        }
                }
                if (argc < 3) {
                        error("too few parameters");
                        usage_with_options(git_notes_usage, options);
                }
                from_ref = argv[i++];
                if (get_sha1(from_ref, from_obj))
                        die("Failed to resolve '%s' as a valid ref.", from_ref);
        }

        given_object = argc > i;
        object_ref = given_object ? argv[i++] : "HEAD";

        if (argc > i || (prune && given_object)) {
                error("too many parameters");
                usage_with_options(git_notes_usage, options);
        }

        if (get_sha1(object_ref, object))
                die("Failed to resolve '%s' as a valid ref.", object_ref);

        init_notes(NULL, NULL, NULL, 0);
        t = &default_notes_tree;

        if (prefixcmp(t->ref, "refs/notes/"))
                die("Refusing to %s notes in %s (outside of refs/notes/)",
                    argv[0], t->ref);

        note = get_note(t, object);

        /* list command */

        if (list) {
                if (given_object) {
                        if (note) {
                                puts(sha1_to_hex(note));
                                goto end;
                        }
                } else {
                        retval = for_each_note(t, 0, list_each_note, NULL);
                        goto end;
                }
        }

        /* show command */

        if ((list || show) && !note) {
                error("No note found for object %s.", sha1_to_hex(object));
                retval = 1;
                goto end;
        } else if (show) {
                const char *show_args[3] = {"show", sha1_to_hex(note), NULL};
                retval = execv_git_cmd(show_args);
                goto end;
        }

        /* add/append/edit/remove/prune command */

        if ((add || copy) && note) {
                if (!force) {
                        error("Cannot %s notes. Found existing notes for object"
                              " %s. Use '-f' to overwrite existing notes",
                              argv[0], sha1_to_hex(object));
                        retval = 1;
                        goto end;
                }
                fprintf(stderr, "Overwriting existing notes for object %s\n",
                        sha1_to_hex(object));
        }

        if (remove) {
                msg.given = 1;
                msg.use_editor = 0;
                strbuf_reset(&(msg.buf));
        }

        if (prune) {
                hashclr(new_note);
                prune_notes(t);
                goto commit;
        } else if (copy) {
                const unsigned char *from_note = get_note(t, from_obj);
                if (!from_note) {
                        error("Missing notes on source object %s. Cannot copy.",
                              sha1_to_hex(from_obj));
                        retval = 1;
                        goto end;
                }
                hashcpy(new_note, from_note);
        } else
                create_note(object, &msg, append, note, new_note);

        if (is_null_sha1(new_note))
                remove_note(t, object);
        else
                add_note(t, object, new_note, combine_notes_overwrite);

commit:
        snprintf(logmsg, sizeof(logmsg), "Notes %s by 'git notes %s'",
                 is_null_sha1(new_note) ? "removed" : "added", argv[0]);
        commit_notes(t, logmsg);

end:
        free_notes(t);
        strbuf_release(&(msg.buf));
        return retval;
}