#include "cache.h"
#include "dir.h"
#include "resolve-undo.h"
#include "string-list.h"

/* The only error case is to run out of memory in string-list */
void record_resolve_undo(struct index_state *istate, struct cache_entry *ce)
{
        struct string_list_item *lost;
        struct resolve_undo_info *ui;
        struct string_list *resolve_undo;
        int stage = ce_stage(ce);

        if (!stage)
                return;

        if (!istate->resolve_undo) {
                resolve_undo = xcalloc(1, sizeof(*resolve_undo));
                resolve_undo->strdup_strings = 1;
                istate->resolve_undo = resolve_undo;
        }
        resolve_undo = istate->resolve_undo;
        lost = string_list_insert(resolve_undo, ce->name);
        if (!lost->util)
                lost->util = xcalloc(1, sizeof(*ui));
        ui = lost->util;
        hashcpy(ui->sha1[stage - 1], ce->sha1);
        ui->mode[stage - 1] = ce->ce_mode;
}

void resolve_undo_write(struct strbuf *sb, struct string_list *resolve_undo)
{
        struct string_list_item *item;
        for_each_string_list_item(item, resolve_undo) {
                struct resolve_undo_info *ui = item->util;
                int i;

                if (!ui)
                        continue;
                strbuf_addstr(sb, item->string);
                strbuf_addch(sb, 0);
                for (i = 0; i < 3; i++)
                        strbuf_addf(sb, "%o%c", ui->mode[i], 0);
                for (i = 0; i < 3; i++) {
                        if (!ui->mode[i])
                                continue;
                        strbuf_add(sb, ui->sha1[i], 20);
                }
        }
}

struct string_list *resolve_undo_read(const char *data, unsigned long size)
{
        struct string_list *resolve_undo;
        size_t len;
        char *endptr;
        int i;

        resolve_undo = xcalloc(1, sizeof(*resolve_undo));
        resolve_undo->strdup_strings = 1;

        while (size) {
                struct string_list_item *lost;
                struct resolve_undo_info *ui;

                len = strlen(data) + 1;
                if (size <= len)
                        goto error;
                lost = string_list_insert(resolve_undo, data);
                if (!lost->util)
                        lost->util = xcalloc(1, sizeof(*ui));
                ui = lost->util;
                size -= len;
                data += len;

                for (i = 0; i < 3; i++) {
                        ui->mode[i] = strtoul(data, &endptr, 8);
                        if (!endptr || endptr == data || *endptr)
                                goto error;
                        len = (endptr + 1) - (char*)data;
                        if (size <= len)
                                goto error;
                        size -= len;
                        data += len;
                }

                for (i = 0; i < 3; i++) {
                        if (!ui->mode[i])
                                continue;
                        if (size < 20)
                                goto error;
                        hashcpy(ui->sha1[i], (const unsigned char *)data);
                        size -= 20;
                        data += 20;
                }
        }
        return resolve_undo;

error:
        string_list_clear(resolve_undo, 1);
        error("Index records invalid resolve-undo information");
        return NULL;
}

void resolve_undo_clear_index(struct index_state *istate)
{
        struct string_list *resolve_undo = istate->resolve_undo;
        if (!resolve_undo)
                return;
        string_list_clear(resolve_undo, 1);
        free(resolve_undo);
        istate->resolve_undo = NULL;
        istate->cache_changed |= RESOLVE_UNDO_CHANGED;
}

int unmerge_index_entry_at(struct index_state *istate, int pos)
{
        const struct cache_entry *ce;
        struct string_list_item *item;
        struct resolve_undo_info *ru;
        int i, err = 0, matched;
        char *name;

        if (!istate->resolve_undo)
                return pos;

        ce = istate->cache[pos];
        if (ce_stage(ce)) {
                /* already unmerged */
                while ((pos < istate->cache_nr) &&
                       ! strcmp(istate->cache[pos]->name, ce->name))
                        pos++;
                return pos - 1; /* return the last entry processed */
        }
        item = string_list_lookup(istate->resolve_undo, ce->name);
        if (!item)
                return pos;
        ru = item->util;
        if (!ru)
                return pos;
        matched = ce->ce_flags & CE_MATCHED;
        name = xstrdup(ce->name);
        remove_index_entry_at(istate, pos);
        for (i = 0; i < 3; i++) {
                struct cache_entry *nce;
                if (!ru->mode[i])
                        continue;
                nce = make_cache_entry(ru->mode[i], ru->sha1[i],
                                       name, i + 1, 0);
                if (matched)
                        nce->ce_flags |= CE_MATCHED;
                if (add_index_entry(istate, nce, ADD_CACHE_OK_TO_ADD)) {
                        err = 1;
                        error("cannot unmerge '%s'", name);
                }
        }
        free(name);
        if (err)
                return pos;
        free(ru);
        item->util = NULL;
        return unmerge_index_entry_at(istate, pos);
}

void unmerge_marked_index(struct index_state *istate)
{
        int i;

        if (!istate->resolve_undo)
                return;

        for (i = 0; i < istate->cache_nr; i++) {
                const struct cache_entry *ce = istate->cache[i];
                if (ce->ce_flags & CE_MATCHED)
                        i = unmerge_index_entry_at(istate, i);
        }
}

void unmerge_index(struct index_state *istate, const struct pathspec *pathspec)
{
        int i;

        if (!istate->resolve_undo)
                return;

        for (i = 0; i < istate->cache_nr; i++) {
                const struct cache_entry *ce = istate->cache[i];
                if (!ce_path_match(ce, pathspec, NULL))
                        continue;
                i = unmerge_index_entry_at(istate, i);
        }
}