#include "cache.h"
#include "diff.h"
#include "commit.h"
#include "log-tree.h"

static void show_parents(struct commit *commit, int abbrev)
{
        struct commit_list *p;
        for (p = commit->parents; p ; p = p->next) {
                struct commit *parent = p->item;
                printf(" %s", diff_unique_abbrev(parent->object.sha1, abbrev));
        }
}

void show_log(struct rev_info *opt, struct log_info *log, const char *sep)
{
        static char this_header[16384];
        struct commit *commit = log->commit, *parent = log->parent;
        int abbrev = opt->diffopt.abbrev;
        int abbrev_commit = opt->abbrev_commit ? opt->abbrev : 40;
        const char *extra;
        int len;

        opt->loginfo = NULL;
        if (!opt->verbose_header) {
                fputs(diff_unique_abbrev(commit->object.sha1, abbrev_commit), stdout);
                if (opt->parents)
                        show_parents(commit, abbrev_commit);
                putchar('\n');
                return;
        }

        /*
         * The "oneline" format has several special cases:
         *  - The pretty-printed commit lacks a newline at the end
         *    of the buffer, but we do want to make sure that we
         *    have a newline there. If the separator isn't already
         *    a newline, add an extra one.
         *  - unlike other log messages, the one-line format does
         *    not have an empty line between entries.
         */
        extra = "";
        if (*sep != '\n' && opt->commit_format == CMIT_FMT_ONELINE)
                extra = "\n";
        if (opt->shown_one && opt->commit_format != CMIT_FMT_ONELINE)
                putchar('\n');
        opt->shown_one = 1;

        /*
         * Print header line of header..
         */
        printf("%s%s",
                opt->commit_format == CMIT_FMT_ONELINE ? "" : "commit ",
                diff_unique_abbrev(commit->object.sha1, abbrev_commit));
        if (opt->parents)
                show_parents(commit, abbrev_commit);
        if (parent)
                printf(" (from %s)", diff_unique_abbrev(parent->object.sha1, abbrev_commit));
        putchar(opt->commit_format == CMIT_FMT_ONELINE ? ' ' : '\n');

        /*
         * And then the pretty-printed message itself
         */
        len = pretty_print_commit(opt->commit_format, commit, ~0u, this_header, sizeof(this_header), abbrev);
        printf("%s%s%s", this_header, extra, sep);
}

int log_tree_diff_flush(struct rev_info *opt)
{
        diffcore_std(&opt->diffopt);

        if (diff_queue_is_empty()) {
                int saved_fmt = opt->diffopt.output_format;
                opt->diffopt.output_format = DIFF_FORMAT_NO_OUTPUT;
                diff_flush(&opt->diffopt);
                opt->diffopt.output_format = saved_fmt;
                return 0;
        }

        if (opt->loginfo && !opt->no_commit_id)
                show_log(opt, opt->loginfo, opt->diffopt.with_stat ? "---\n" : "\n");
        diff_flush(&opt->diffopt);
        return 1;
}

static int diff_root_tree(struct rev_info *opt,
                          const unsigned char *new, const char *base)
{
        int retval;
        void *tree;
        struct tree_desc empty, real;

        tree = read_object_with_reference(new, tree_type, &real.size, NULL);
        if (!tree)
                die("unable to read root tree (%s)", sha1_to_hex(new));
        real.buf = tree;

        empty.buf = "";
        empty.size = 0;
        retval = diff_tree(&empty, &real, base, &opt->diffopt);
        free(tree);
        log_tree_diff_flush(opt);
        return retval;
}

static int do_diff_combined(struct rev_info *opt, struct commit *commit)
{
        unsigned const char *sha1 = commit->object.sha1;

        diff_tree_combined_merge(sha1, opt->dense_combined_merges, opt);
        return !opt->loginfo;
}

/*
 * Show the diff of a commit.
 *
 * Return true if we printed any log info messages
 */
static int log_tree_diff(struct rev_info *opt, struct commit *commit, struct log_info *log)
{
        int showed_log;
        struct commit_list *parents;
        unsigned const char *sha1 = commit->object.sha1;

        if (!opt->diff)
                return 0;

        /* Root commit? */
        parents = commit->parents;
        if (!parents) {
                if (opt->show_root_diff)
                        diff_root_tree(opt, sha1, "");
                return !opt->loginfo;
        }

        /* More than one parent? */
        if (parents && parents->next) {
                if (opt->ignore_merges)
                        return 0;
                else if (opt->combine_merges)
                        return do_diff_combined(opt, commit);

                /* If we show individual diffs, show the parent info */
                log->parent = parents->item;
        }

        showed_log = 0;
        for (;;) {
                struct commit *parent = parents->item;

                diff_tree_sha1(parent->object.sha1, sha1, "", &opt->diffopt);
                log_tree_diff_flush(opt);

                showed_log |= !opt->loginfo;

                /* Set up the log info for the next parent, if any.. */
                parents = parents->next;
                if (!parents)
                        break;
                log->parent = parents->item;
                opt->loginfo = log;
        }
        return showed_log;
}

int log_tree_commit(struct rev_info *opt, struct commit *commit)
{
        struct log_info log;

        log.commit = commit;
        log.parent = NULL;
        opt->loginfo = &log;

        if (!log_tree_diff(opt, commit, &log) && opt->loginfo && opt->always_show_header) {
                log.parent = NULL;
                show_log(opt, opt->loginfo, "");
        }
        opt->loginfo = NULL;
        return 0;
}