#include "cache.h"
#include "commit.h"
#include "refs.h"
#include "diff.h"
#include "revision.h"
#include "string-list.h"
#include "reflog-walk.h"

struct complete_reflogs {
        char *ref;
        const char *short_ref;
        struct reflog_info {
                unsigned char osha1[20], nsha1[20];
                char *email;
                unsigned long timestamp;
                int tz;
                char *message;
        } *items;
        int nr, alloc;
};

static int read_one_reflog(unsigned char *osha1, unsigned char *nsha1,
                const char *email, unsigned long timestamp, int tz,
                const char *message, void *cb_data)
{
        struct complete_reflogs *array = cb_data;
        struct reflog_info *item;

        if (array->nr >= array->alloc) {
                array->alloc = alloc_nr(array->nr + 1);
                array->items = xrealloc(array->items, array->alloc *
                        sizeof(struct reflog_info));
        }
        item = array->items + array->nr;
        memcpy(item->osha1, osha1, 20);
        memcpy(item->nsha1, nsha1, 20);
        item->email = xstrdup(email);
        item->timestamp = timestamp;
        item->tz = tz;
        item->message = xstrdup(message);
        array->nr++;
        return 0;
}

static struct complete_reflogs *read_complete_reflog(const char *ref)
{
        struct complete_reflogs *reflogs =
                xcalloc(sizeof(struct complete_reflogs), 1);
        reflogs->ref = xstrdup(ref);
        for_each_reflog_ent(ref, read_one_reflog, reflogs);
        if (reflogs->nr == 0) {
                unsigned char sha1[20];
                const char *name = resolve_ref(ref, sha1, 1, NULL);
                if (name)
                        for_each_reflog_ent(name, read_one_reflog, reflogs);
        }
        if (reflogs->nr == 0) {
                int len = strlen(ref);
                char *refname = xmalloc(len + 12);
                sprintf(refname, "refs/%s", ref);
                for_each_reflog_ent(refname, read_one_reflog, reflogs);
                if (reflogs->nr == 0) {
                        sprintf(refname, "refs/heads/%s", ref);
                        for_each_reflog_ent(refname, read_one_reflog, reflogs);
                }
                free(refname);
        }
        return reflogs;
}

static int get_reflog_recno_by_time(struct complete_reflogs *array,
        unsigned long timestamp)
{
        int i;
        for (i = array->nr - 1; i >= 0; i--)
                if (timestamp >= array->items[i].timestamp)
                        return i;
        return -1;
}

struct commit_info_lifo {
        struct commit_info {
                struct commit *commit;
                void *util;
        } *items;
        int nr, alloc;
};

static struct commit_info *get_commit_info(struct commit *commit,
                struct commit_info_lifo *lifo, int pop)
{
        int i;
        for (i = 0; i < lifo->nr; i++)
                if (lifo->items[i].commit == commit) {
                        struct commit_info *result = &lifo->items[i];
                        if (pop) {
                                if (i + 1 < lifo->nr)
                                        memmove(lifo->items + i,
                                                lifo->items + i + 1,
                                                (lifo->nr - i) *
                                                sizeof(struct commit_info));
                                lifo->nr--;
                        }
                        return result;
                }
        return NULL;
}

static void add_commit_info(struct commit *commit, void *util,
                struct commit_info_lifo *lifo)
{
        struct commit_info *info;
        if (lifo->nr >= lifo->alloc) {
                lifo->alloc = alloc_nr(lifo->nr + 1);
                lifo->items = xrealloc(lifo->items,
                        lifo->alloc * sizeof(struct commit_info));
        }
        info = lifo->items + lifo->nr;
        info->commit = commit;
        info->util = util;
        lifo->nr++;
}

struct commit_reflog {
        int recno;
        enum selector_type {
                SELECTOR_NONE,
                SELECTOR_INDEX,
                SELECTOR_DATE
        } selector;
        struct complete_reflogs *reflogs;
};

struct reflog_walk_info {
        struct commit_info_lifo reflogs;
        struct string_list complete_reflogs;
        struct commit_reflog *last_commit_reflog;
};

void init_reflog_walk(struct reflog_walk_info** info)
{
        *info = xcalloc(sizeof(struct reflog_walk_info), 1);
}

int add_reflog_for_walk(struct reflog_walk_info *info,
                struct commit *commit, const char *name)
{
        unsigned long timestamp = 0;
        int recno = -1;
        struct string_list_item *item;
        struct complete_reflogs *reflogs;
        char *branch, *at = strchr(name, '@');
        struct commit_reflog *commit_reflog;
        enum selector_type selector = SELECTOR_NONE;

        if (commit->object.flags & UNINTERESTING)
                die ("Cannot walk reflogs for %s", name);

        branch = xstrdup(name);
        if (at && at[1] == '{') {
                char *ep;
                branch[at - name] = '\0';
                recno = strtoul(at + 2, &ep, 10);
                if (*ep != '}') {
                        recno = -1;
                        timestamp = approxidate(at + 2);
                        selector = SELECTOR_DATE;
                }
                else
                        selector = SELECTOR_INDEX;
        } else
                recno = 0;

        item = string_list_lookup(&info->complete_reflogs, branch);
        if (item)
                reflogs = item->util;
        else {
                if (*branch == '\0') {
                        unsigned char sha1[20];
                        const char *head = resolve_ref("HEAD", sha1, 0, NULL);
                        if (!head)
                                die ("No current branch");
                        free(branch);
                        branch = xstrdup(head);
                }
                reflogs = read_complete_reflog(branch);
                if (!reflogs || reflogs->nr == 0) {
                        unsigned char sha1[20];
                        char *b;
                        if (dwim_log(branch, strlen(branch), sha1, &b) == 1) {
                                if (reflogs) {
                                        free(reflogs->ref);
                                        free(reflogs);
                                }
                                free(branch);
                                branch = b;
                                reflogs = read_complete_reflog(branch);
                        }
                }
                if (!reflogs || reflogs->nr == 0)
                        return -1;
                string_list_insert(&info->complete_reflogs, branch)->util
                        = reflogs;
        }

        commit_reflog = xcalloc(sizeof(struct commit_reflog), 1);
        if (recno < 0) {
                commit_reflog->recno = get_reflog_recno_by_time(reflogs, timestamp);
                if (commit_reflog->recno < 0) {
                        free(branch);
                        free(commit_reflog);
                        return -1;
                }
        } else
                commit_reflog->recno = reflogs->nr - recno - 1;
        commit_reflog->selector = selector;
        commit_reflog->reflogs = reflogs;

        add_commit_info(commit, commit_reflog, &info->reflogs);
        return 0;
}

void fake_reflog_parent(struct reflog_walk_info *info, struct commit *commit)
{
        struct commit_info *commit_info =
                get_commit_info(commit, &info->reflogs, 0);
        struct commit_reflog *commit_reflog;
        struct reflog_info *reflog;

        info->last_commit_reflog = NULL;
        if (!commit_info)
                return;

        commit_reflog = commit_info->util;
        if (commit_reflog->recno < 0) {
                commit->parents = NULL;
                return;
        }

        reflog = &commit_reflog->reflogs->items[commit_reflog->recno];
        info->last_commit_reflog = commit_reflog;
        commit_reflog->recno--;
        commit_info->commit = (struct commit *)parse_object(reflog->osha1);
        if (!commit_info->commit) {
                commit->parents = NULL;
                return;
        }

        commit->parents = xcalloc(sizeof(struct commit_list), 1);
        commit->parents->item = commit_info->commit;
}

void get_reflog_selector(struct strbuf *sb,
                         struct reflog_walk_info *reflog_info,
                         enum date_mode dmode,
                         int shorten)
{
        struct commit_reflog *commit_reflog = reflog_info->last_commit_reflog;
        struct reflog_info *info;
        const char *printed_ref;

        if (!commit_reflog)
                return;

        if (shorten) {
                if (!commit_reflog->reflogs->short_ref)
                        commit_reflog->reflogs->short_ref
                                = shorten_unambiguous_ref(commit_reflog->reflogs->ref, 0);
                printed_ref = commit_reflog->reflogs->short_ref;
        } else {
                printed_ref = commit_reflog->reflogs->ref;
        }

        strbuf_addf(sb, "%s@{", printed_ref);
        if (commit_reflog->selector == SELECTOR_DATE || dmode) {
                info = &commit_reflog->reflogs->items[commit_reflog->recno+1];
                strbuf_addstr(sb, show_date(info->timestamp, info->tz, dmode));
        } else {
                strbuf_addf(sb, "%d", commit_reflog->reflogs->nr
                            - 2 - commit_reflog->recno);
        }

        strbuf_addch(sb, '}');
}

void get_reflog_message(struct strbuf *sb,
                        struct reflog_walk_info *reflog_info)
{
        struct commit_reflog *commit_reflog = reflog_info->last_commit_reflog;
        struct reflog_info *info;
        size_t len;

        if (!commit_reflog)
                return;

        info = &commit_reflog->reflogs->items[commit_reflog->recno+1];
        len = strlen(info->message);
        if (len > 0)
                len--; /* strip away trailing newline */
        strbuf_add(sb, info->message, len);
}

void show_reflog_message(struct reflog_walk_info *reflog_info, int oneline,
        enum date_mode dmode)
{
        if (reflog_info && reflog_info->last_commit_reflog) {
                struct commit_reflog *commit_reflog = reflog_info->last_commit_reflog;
                struct reflog_info *info;
                struct strbuf selector = STRBUF_INIT;

                info = &commit_reflog->reflogs->items[commit_reflog->recno+1];
                get_reflog_selector(&selector, reflog_info, dmode, 0);
                if (oneline) {
                        printf("%s: %s", selector.buf, info->message);
                }
                else {
                        printf("Reflog: %s (%s)\nReflog message: %s",
                               selector.buf, info->email, info->message);
                }

                strbuf_release(&selector);
        }
}