/*
 * 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"

static const char * const git_notes_usage[] = {
        "git notes edit [-m <msg> | -F <file>] [<object>]",
        "git notes show [<object>]",
        NULL
};

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

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 strbuf *buf,
                        int skip_editor,
                        const unsigned char *prev,
                        unsigned char *result)
{
        char *path = NULL;

        if (!skip_editor) {
                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 (prev)
                        write_note_data(fd, prev);
                write_or_die(fd, note_template, strlen(note_template));

                write_commented_object(fd, object);

                close(fd);

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

        stripspace(buf, 1);

        if (!skip_editor && !buf->len) {
                fprintf(stderr, "Removing note for object %s\n",
                        sha1_to_hex(object));
                hashclr(result);
        } else {
                if (write_sha1_file(buf->buf, 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);
        }
}

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

static int parse_msg_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\n");
        strbuf_addstr(&(msg->buf), arg);
        msg->given = 1;
        return 0;
}

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");

        /* 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;
}

int cmd_notes(int argc, const char **argv, const char *prefix)
{
        struct strbuf buf = STRBUF_INIT;
        struct notes_tree *t;
        unsigned char object[20], new_note[20];
        const unsigned char *note;
        const char *object_ref;
        int edit = 0, show = 0;
        const char *msgfile = NULL;
        struct msg_arg msg = { 0, STRBUF_INIT };
        struct option options[] = {
                OPT_GROUP("Notes edit options"),
                OPT_CALLBACK('m', NULL, &msg, "msg",
                             "note contents as a string", parse_msg_arg),
                OPT_FILENAME('F', NULL, &msgfile, "note contents in a file"),
                OPT_END()
        };

        git_config(git_default_config, NULL);

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

        if (argc && !strcmp(argv[0], "edit"))
                edit = 1;
        else if (argc && !strcmp(argv[0], "show"))
                show = 1;

        if (edit + show != 1)
                usage_with_options(git_notes_usage, options);

        object_ref = argc == 2 ? argv[1] : "HEAD";
        if (argc > 2) {
                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/)",
                    edit ? "edit" : "show", t->ref);

        note = get_note(t, object);

        /* show command */

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

        /* edit command */

        if (msg.given || msgfile) {
                if (msg.given && msgfile) {
                        error("mixing -m and -F options is not allowed.");
                        usage_with_options(git_notes_usage, options);
                }
                if (msg.given)
                        strbuf_addbuf(&buf, &(msg.buf));
                else {
                        if (!strcmp(msgfile, "-")) {
                                if (strbuf_read(&buf, 0, 1024) < 0)
                                        die_errno("cannot read '%s'", msgfile);
                        } else {
                                if (strbuf_read_file(&buf, msgfile, 1024) < 0)
                                        die_errno("could not open or read '%s'",
                                                msgfile);
                        }
                }
        }

        create_note(object, &buf, msg.given || msgfile, note, new_note);
        add_note(t, object, new_note, combine_notes_overwrite);
        commit_notes(t, "Note added by 'git notes edit'");

        free_notes(t);
        strbuf_release(&buf);
        return 0;
}