#include "cache.h"
#include "commit.h"

#define SEEN            (1u << 0)
#define INTERESTING     (1u << 1)
#define UNINTERESTING   (1u << 2)

static const char rev_list_usage[] =
        "usage: git-rev-list [OPTION] commit-id <commit-id>\n"
                      "  --max-count=nr\n"
                      "  --max-age=epoch\n"
                      "  --min-age=epoch\n"
                      "  --header\n"
                      "  --pretty";

static int verbose_header = 0;
static int show_parents = 0;
static int hdr_termination = 0;
static const char *prefix = "";
static unsigned long max_age = -1;
static unsigned long min_age = -1;
static int max_count = -1;
static enum cmit_fmt commit_format = CMIT_FMT_RAW;

static void show_commit(struct commit *commit)
{
        printf("%s%s", prefix, sha1_to_hex(commit->object.sha1));
        if (show_parents) {
                struct commit_list *parents = commit->parents;
                while (parents) {
                        printf(" %s", sha1_to_hex(parents->item->object.sha1));
                        parents = parents->next;
                }
        }
        putchar('\n');
        if (verbose_header) {
                static char pretty_header[16384];
                pretty_print_commit(commit_format, commit->buffer, ~0, pretty_header, sizeof(pretty_header));
                printf("%s%c", pretty_header, hdr_termination);
        }
}

static void show_commit_list(struct commit_list *list)
{
        while (list) {
                struct commit *commit = pop_most_recent_commit(&list, SEEN);

                if (commit->object.flags & UNINTERESTING)
                        continue;
                if (min_age != -1 && (commit->date > min_age))
                        continue;
                if (max_age != -1 && (commit->date < max_age))
                        break;
                if (max_count != -1 && !max_count--)
                        break;
                show_commit(commit);
        }
}

static void mark_parents_uninteresting(struct commit *commit)
{
        struct commit_list *parents = commit->parents;

        while (parents) {
                struct commit *commit = parents->item;
                commit->object.flags |= UNINTERESTING;
                parents = parents->next;
        }
}

static int everybody_uninteresting(struct commit_list *list)
{
        while (list) {
                struct commit *commit = list->item;
                list = list->next;
                if (commit->object.flags & UNINTERESTING)
                        continue;
                return 0;
        }
        return 1;
}

struct commit_list *limit_list(struct commit_list *list)
{
        struct commit_list *newlist = NULL;
        struct commit_list **p = &newlist;
        do {
                struct commit *commit = pop_most_recent_commit(&list, SEEN);
                struct object *obj = &commit->object;

                if (obj->flags & UNINTERESTING) {
                        mark_parents_uninteresting(commit);
                        if (everybody_uninteresting(list))
                                break;
                        continue;
                }
                p = &commit_list_insert(commit, p)->next;
        } while (list);
        return newlist;
}

static enum cmit_fmt get_commit_format(const char *arg)
{
        if (!*arg)
                return CMIT_FMT_DEFAULT;
        if (!strcmp(arg, "=raw"))
                return CMIT_FMT_RAW;
        if (!strcmp(arg, "=medium"))
                return CMIT_FMT_MEDIUM;
        if (!strcmp(arg, "=short"))
                return CMIT_FMT_SHORT;
        usage(rev_list_usage);  
}                       


int main(int argc, char **argv)
{
        struct commit_list *list = NULL;
        int i, limited = 0;

        for (i = 1 ; i < argc; i++) {
                int flags;
                char *arg = argv[i];
                unsigned char sha1[20];
                struct commit *commit;

                if (!strncmp(arg, "--max-count=", 12)) {
                        max_count = atoi(arg + 12);
                        continue;
                }
                if (!strncmp(arg, "--max-age=", 10)) {
                        max_age = atoi(arg + 10);
                        continue;
                }
                if (!strncmp(arg, "--min-age=", 10)) {
                        min_age = atoi(arg + 10);
                        continue;
                }
                if (!strcmp(arg, "--header")) {
                        verbose_header = 1;
                        continue;
                }
                if (!strncmp(arg, "--pretty", 8)) {
                        commit_format = get_commit_format(arg+8);
                        verbose_header = 1;
                        hdr_termination = '\n';
                        prefix = "commit ";
                        continue;
                }
                if (!strcmp(arg, "--parents")) {
                        show_parents = 1;
                        continue;
                }

                flags = 0;
                if (*arg == '^') {
                        flags = UNINTERESTING;
                        arg++;
                        limited = 1;
                }
                if (get_sha1(arg, sha1))
                        usage(rev_list_usage);
                commit = lookup_commit_reference(sha1);
                if (!commit || parse_commit(commit) < 0)
                        die("bad commit object %s", arg);
                commit->object.flags |= flags;
                commit_list_insert(commit, &list);
        }

        if (!list)
                usage(rev_list_usage);

        if (limited)
                list = limit_list(list);

        show_commit_list(list);
        return 0;
}