#include <stdio.h>
#include <assert.h>
#include <string.h>
#include <unistd.h>
#include <errno.h>

#include "md5util.h"
#include "diff.h"
#include "dbutil.h"

struct cb_info {
    struct syrep_db_context *c1;
    struct syrep_db_context *c2;
    const char *root;
};

int conflict_phase(DB *ddb, struct syrep_name *name, struct diff_entry *de, void *p) {
    struct cb_info *cb_info = p;
    char path[PATH_MAX+1];

    assert(ddb && name && de && p);

    if (de->action != DIFF_CONFLICT)
        return 0;

    snprintf(path, sizeof(path), "%s/%s", cb_info->root, name->path);
    fprintf(stderr, "QUERY %s\n", path);

    return 0;
}

int copy_phase(DB *ddb, struct syrep_name *name, struct diff_entry *de, void *p) {
    struct cb_info *cb_info = p;
    struct syrep_name name2;
    struct syrep_md md;
    char path[PATH_MAX+1];
    int f;
    char d[SYREP_DIGESTLENGTH*2+1];

    assert(ddb && name && de && p);

    if (de->action != DIFF_COPY)
        return 0;

    if (de->repository == cb_info->c2)
        return 0;

    snprintf(path, sizeof(path), "%s/%s", cb_info->root, name->path);

    if ((f = get_current_md_by_name(cb_info->c1, name, &md)) < 0)
        return -1;


    if (!f) {
        fprintf(stderr, "Diff invalid!\n");
        return -1;
    }

    fhex(md.digest, SYREP_DIGESTLENGTH, d);
    d[SYREP_DIGESTLENGTH*2] = 0;

    fprintf(stderr, "Searching for %s\n", d);
    
    if ((f = get_current_name_by_md(cb_info->c2, &md, &name2)) < 0)
        return -1;
    
    if (f) {
        char path2[PATH_MAX+1];
        snprintf(path2, sizeof(path2), "%s/%s", cb_info->root, name2.path);
        fprintf(stderr, "Linking file <%s> to <%s>\n", path2, path);
        if (link(path2, path) < 0) {
            fprintf(stderr, "Failed to link: %s\n", strerror(errno));
            return -1;
        }
    } else
        fprintf(stderr, "MISSING FILE %s\n", path);

    return 0;
}

int delete_phase(DB *ddb, struct syrep_name *name, struct diff_entry *de, void *p) {
    struct cb_info *cb_info = p;
    char path[PATH_MAX+1];

    assert(ddb && name && de && p);
    
    if (de->action != DIFF_DELETE)
        return 0;

    if (de->repository == cb_info->c1)
        return 0;

    snprintf(path, sizeof(path), "%s/%s", cb_info->root, name->path);
    fprintf(stderr, "Deleting file <%s>\n", path);

    if (unlink(path) < 0) {
        fprintf(stderr, "Failed to unlink: %s\n", strerror(errno));
        return -1;
    }
    
    return 0;
}

/* Merges c1 into c2 in directory "root" */
int merge_snapshot(struct syrep_db_context *c1, struct syrep_db_context *c2, const char* root) {
    struct cb_info cb_info;
    DB *ddb = NULL;

    memset(&cb_info, 0, sizeof(cb_info));
    cb_info.c1 = c1;
    cb_info.c2 = c2;
    cb_info.root = root;

    if (!(ddb = make_diff(c1, c2)))
        goto finish;

    if (diff_foreach(ddb, conflict_phase, &cb_info) < 0)
        goto finish;

    if (diff_foreach(ddb, copy_phase, &cb_info) < 0)
        goto finish;

    if (diff_foreach(ddb, delete_phase, &cb_info) < 0)
        goto finish;
    
finish:
    if (ddb)
        ddb->close(ddb, 0);
    
    return 0;
}