#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 {
                struct object_id ooid, noid;
                char *email;
                timestamp_t timestamp;
                int tz;
                char *message;
        } *items;
        int nr, alloc;
};

static int read_one_reflog(struct object_id *ooid, struct object_id *noid,
                const char *email, timestamp_t timestamp, int tz,
                const char *message, void *cb_data)
{
        struct complete_reflogs *array = cb_data;
        struct reflog_info *item;

        ALLOC_GROW(array->items, array->nr + 1, array->alloc);
        item = array->items + array->nr;
        oidcpy(&item->ooid, ooid);
        oidcpy(&item->noid, noid);
        item->email = xstrdup(email);
        item->timestamp = timestamp;
        item->tz = tz;
        item->message = xstrdup(message);
        array->nr++;
        return 0;
}

static void free_complete_reflog(struct complete_reflogs *array)
{
        int i;

        if (!array)
                return;

        for (i = 0; i < array->nr; i++) {
                free(array->items[i].email);
                free(array->items[i].message);
        }
        free(array->items);
        free(array->ref);
        free(array);
}

static struct complete_reflogs *read_complete_reflog(const char *ref)
{
        struct complete_reflogs *reflogs =
                xcalloc(1, sizeof(struct complete_reflogs));
        reflogs->ref = xstrdup(ref);
        for_each_reflog_ent(ref, read_one_reflog, reflogs);
        if (reflogs->nr == 0) {
                const char *name;
                void *name_to_free;
                name = name_to_free = resolve_refdup(ref, RESOLVE_REF_READING,
                                                     NULL, NULL);
                if (name) {
                        for_each_reflog_ent(name, read_one_reflog, reflogs);
                        free(name_to_free);
                }
        }
        if (reflogs->nr == 0) {
                char *refname = xstrfmt("refs/%s", ref);
                for_each_reflog_ent(refname, read_one_reflog, reflogs);
                if (reflogs->nr == 0) {
                        free(refname);
                        refname = xstrfmt("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,
        timestamp_t timestamp)
{
        int i;
        for (i = array->nr - 1; i >= 0; i--)
                if (timestamp >= array->items[i].timestamp)
                        return i;
        return -1;
}

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_reflog **logs;
        size_t nr, alloc;
        struct string_list complete_reflogs;
        struct commit_reflog *last_commit_reflog;
};

void init_reflog_walk(struct reflog_walk_info **info)
{
        *info = xcalloc(1, sizeof(struct reflog_walk_info));
        (*info)->complete_reflogs.strdup_strings = 1;
}

int add_reflog_for_walk(struct reflog_walk_info *info,
                struct commit *commit, const char *name)
{
        timestamp_t 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') {
                        free(branch);
                        branch = resolve_refdup("HEAD", 0, NULL, NULL);
                        if (!branch)
                                die ("No current branch");

                }
                reflogs = read_complete_reflog(branch);
                if (!reflogs || reflogs->nr == 0) {
                        struct object_id oid;
                        char *b;
                        int ret = dwim_log(branch, strlen(branch),
                                           oid.hash, &b);
                        if (ret > 1)
                                free(b);
                        else if (ret == 1) {
                                free_complete_reflog(reflogs);
                                free(branch);
                                branch = b;
                                reflogs = read_complete_reflog(branch);
                        }
                }
                if (!reflogs || reflogs->nr == 0) {
                        free_complete_reflog(reflogs);
                        free(branch);
                        return -1;
                }
                string_list_insert(&info->complete_reflogs, branch)->util
                        = reflogs;
        }
        free(branch);

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

        ALLOC_GROW(info->logs, info->nr + 1, info->alloc);
        info->logs[info->nr++] = commit_reflog;

        return 0;
}

void get_reflog_selector(struct strbuf *sb,
                         struct reflog_walk_info *reflog_info,
                         const struct date_mode *dmode, int force_date,
                         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 ||
            (commit_reflog->selector == SELECTOR_NONE && force_date)) {
                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);
}

const char *get_reflog_ident(struct reflog_walk_info *reflog_info)
{
        struct commit_reflog *commit_reflog = reflog_info->last_commit_reflog;
        struct reflog_info *info;

        if (!commit_reflog)
                return NULL;

        info = &commit_reflog->reflogs->items[commit_reflog->recno+1];
        return info->email;
}

timestamp_t get_reflog_timestamp(struct reflog_walk_info *reflog_info)
{
        struct commit_reflog *commit_reflog = reflog_info->last_commit_reflog;
        struct reflog_info *info;

        if (!commit_reflog)
                return 0;

        info = &commit_reflog->reflogs->items[commit_reflog->recno+1];
        return info->timestamp;
}

void show_reflog_message(struct reflog_walk_info *reflog_info, int oneline,
                         const struct date_mode *dmode, int force_date)
{
        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, force_date, 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);
        }
}

int reflog_walk_empty(struct reflog_walk_info *info)
{
        return !info || !info->nr;
}

static struct commit *next_reflog_commit(struct commit_reflog *log)
{
        for (; log->recno >= 0; log->recno--) {
                struct reflog_info *entry = &log->reflogs->items[log->recno];
                struct object *obj = parse_object(&entry->noid);

                if (obj && obj->type == OBJ_COMMIT)
                        return (struct commit *)obj;
        }
        return NULL;
}

static timestamp_t log_timestamp(struct commit_reflog *log)
{
        return log->reflogs->items[log->recno].timestamp;
}

struct commit *next_reflog_entry(struct reflog_walk_info *walk)
{
        struct commit_reflog *best = NULL;
        struct commit *best_commit = NULL;
        size_t i;

        for (i = 0; i < walk->nr; i++) {
                struct commit_reflog *log = walk->logs[i];
                struct commit *commit = next_reflog_commit(log);

                if (!commit)
                        continue;

                if (!best || log_timestamp(log) > log_timestamp(best)) {
                        best = log;
                        best_commit = commit;
                }
        }

        if (best) {
                best->recno--;
                walk->last_commit_reflog = best;
                return best_commit;
        }

        return NULL;
}