#include "pull.h"

#include "cache.h"
#include "commit.h"
#include "tree.h"
#include "tag.h"
#include "blob.h"
#include "refs.h"

const char *write_ref = NULL;

const unsigned char *current_ref = NULL;

int get_tree = 0;
int get_history = 0;
int get_all = 0;
int get_verbosely = 0;
static unsigned char current_commit_sha1[20];

void pull_say(const char *fmt, const char *hex) 
{
        if (get_verbosely)
                fprintf(stderr, fmt, hex);
}

static void report_missing(const char *what, const unsigned char *missing)
{
        char missing_hex[41];

        strcpy(missing_hex, sha1_to_hex(missing));;
        fprintf(stderr,
                "Cannot obtain needed %s %s\nwhile processing commit %s.\n",
                what, missing_hex, sha1_to_hex(current_commit_sha1));
}

static int make_sure_we_have_it(const char *what, unsigned char *sha1)
{
        int status = 0;

        if (!has_sha1_file(sha1)) {
                status = fetch(sha1);
                if (status && what)
                        report_missing(what, sha1);
        }
        return status;
}

static int process(unsigned char *sha1, const char *type);

static int process_tree(struct tree *tree)
{
        struct tree_entry_list *entries;

        if (parse_tree(tree))
                return -1;

        for (entries = tree->entries; entries; entries = entries->next) {
                if (process(entries->item.any->sha1,
                            entries->directory ? tree_type : blob_type))
                        return -1;
        }
        return 0;
}

static int process_commit(struct commit *commit)
{
        if (parse_commit(commit))
                return -1;

        memcpy(current_commit_sha1, commit->object.sha1, 20);

        if (get_tree) {
                if (process(commit->tree->object.sha1, tree_type))
                        return -1;
                if (!get_all)
                        get_tree = 0;
        }
        if (get_history) {
                struct commit_list *parents = commit->parents;
                for (; parents; parents = parents->next) {
                        if (has_sha1_file(parents->item->object.sha1))
                                continue;
                        if (process(parents->item->object.sha1,
                                    commit_type))
                                return -1;
                }
        }
        return 0;
}

static int process_tag(struct tag *tag)
{
        if (parse_tag(tag))
                return -1;
        return process(tag->tagged->sha1, NULL);
}

static struct object_list *process_queue = NULL;
static struct object_list **process_queue_end = &process_queue;

static int process_object(struct object *obj)
{
        if (obj->type == commit_type) {
                if (process_commit((struct commit *)obj))
                        return -1;
                return 0;
        }
        if (obj->type == tree_type) {
                if (process_tree((struct tree *)obj))
                        return -1;
                return 0;
        }
        if (obj->type == blob_type) {
                return 0;
        }
        if (obj->type == tag_type) {
                if (process_tag((struct tag *)obj))
                        return -1;
                return 0;
        }
        return error("Unable to determine requirements "
                     "of type %s for %s",
                     obj->type, sha1_to_hex(obj->sha1));
}

static int process(unsigned char *sha1, const char *type)
{
        struct object *obj = lookup_object_type(sha1, type);
        if (has_sha1_file(sha1)) {
                parse_object(sha1);
                /* We already have it, so we should scan it now. */
                return process_object(obj);
        }
        if (object_list_contains(process_queue, obj))
                return 0;
        object_list_insert(obj, process_queue_end);
        process_queue_end = &(*process_queue_end)->next;

        //fprintf(stderr, "prefetch %s\n", sha1_to_hex(sha1));
        prefetch(sha1);
                
        return 0;
}

static int loop(void)
{
        while (process_queue) {
                struct object *obj = process_queue->item;
                /*
                fprintf(stderr, "%d objects to pull\n", 
                        object_list_length(process_queue));
                */
                process_queue = process_queue->next;
                if (!process_queue)
                        process_queue_end = &process_queue;

                //fprintf(stderr, "fetch %s\n", sha1_to_hex(obj->sha1));
                
                if (make_sure_we_have_it(obj->type ? obj->type : "object", 
                                         obj->sha1))
                        return -1;
                if (!obj->type)
                        parse_object(obj->sha1);
                if (process_object(obj))
                        return -1;
        }
        return 0;
}

static int interpret_target(char *target, unsigned char *sha1)
{
        if (!get_sha1_hex(target, sha1))
                return 0;
        if (!check_ref_format(target)) {
                if (!fetch_ref(target, sha1)) {
                        return 0;
                }
        }
        return -1;
}


int pull(char *target)
{
        unsigned char sha1[20];
        int fd = -1;

        if (write_ref && current_ref) {
                fd = lock_ref_sha1(write_ref, current_ref);
                if (fd < 0)
                        return -1;
        }

        if (interpret_target(target, sha1))
                return error("Could not interpret %s as something to pull",
                             target);
        if (process(sha1, NULL))
                return -1;
        if (loop())
                return -1;
        
        if (write_ref) {
                if (current_ref) {
                        write_ref_sha1(write_ref, fd, sha1);
                } else {
                        write_ref_sha1_unlocked(write_ref, sha1);
                }
        }
        return 0;
}