#include "cache.h"
#include "lockfile.h"
#include "credential.h"
#include "string-list.h"
#include "parse-options.h"

static struct lock_file credential_lock;

static int parse_credential_file(const char *fn,
                                  struct credential *c,
                                  void (*match_cb)(struct credential *),
                                  void (*other_cb)(struct strbuf *))
{
        FILE *fh;
        struct strbuf line = STRBUF_INIT;
        struct credential entry = CREDENTIAL_INIT;
        int found_credential = 0;

        fh = fopen(fn, "r");
        if (!fh) {
                if (errno != ENOENT && errno != EACCES)
                        die_errno("unable to open %s", fn);
                return found_credential;
        }

        while (strbuf_getline(&line, fh, '\n') != EOF) {
                credential_from_url(&entry, line.buf);
                if (entry.username && entry.password &&
                    credential_match(c, &entry)) {
                        found_credential = 1;
                        if (match_cb) {
                                match_cb(&entry);
                                break;
                        }
                }
                else if (other_cb)
                        other_cb(&line);
        }

        credential_clear(&entry);
        strbuf_release(&line);
        fclose(fh);
        return found_credential;
}

static void print_entry(struct credential *c)
{
        printf("username=%s\n", c->username);
        printf("password=%s\n", c->password);
}

static void print_line(struct strbuf *buf)
{
        strbuf_addch(buf, '\n');
        write_or_die(credential_lock.fd, buf->buf, buf->len);
}

static void rewrite_credential_file(const char *fn, struct credential *c,
                                    struct strbuf *extra)
{
        if (hold_lock_file_for_update(&credential_lock, fn, 0) < 0)
                die_errno("unable to get credential storage lock");
        if (extra)
                print_line(extra);
        parse_credential_file(fn, c, NULL, print_line);
        if (commit_lock_file(&credential_lock) < 0)
                die_errno("unable to commit credential store");
}

static void store_credential_file(const char *fn, struct credential *c)
{
        struct strbuf buf = STRBUF_INIT;

        strbuf_addf(&buf, "%s://", c->protocol);
        strbuf_addstr_urlencode(&buf, c->username, 1);
        strbuf_addch(&buf, ':');
        strbuf_addstr_urlencode(&buf, c->password, 1);
        strbuf_addch(&buf, '@');
        if (c->host)
                strbuf_addstr_urlencode(&buf, c->host, 1);
        if (c->path) {
                strbuf_addch(&buf, '/');
                strbuf_addstr_urlencode(&buf, c->path, 0);
        }

        rewrite_credential_file(fn, c, &buf);
        strbuf_release(&buf);
}

static void store_credential(const struct string_list *fns, struct credential *c)
{
        struct string_list_item *fn;

        /*
         * Sanity check that what we are storing is actually sensible.
         * In particular, we can't make a URL without a protocol field.
         * Without either a host or pathname (depending on the scheme),
         * we have no primary key. And without a username and password,
         * we are not actually storing a credential.
         */
        if (!c->protocol || !(c->host || c->path) || !c->username || !c->password)
                return;

        for_each_string_list_item(fn, fns)
                if (!access(fn->string, F_OK)) {
                        store_credential_file(fn->string, c);
                        return;
                }
        /*
         * Write credential to the filename specified by fns->items[0], thus
         * creating it
         */
        if (fns->nr)
                store_credential_file(fns->items[0].string, c);
}

static void remove_credential(const struct string_list *fns, struct credential *c)
{
        struct string_list_item *fn;

        /*
         * Sanity check that we actually have something to match
         * against. The input we get is a restrictive pattern,
         * so technically a blank credential means "erase everything".
         * But it is too easy to accidentally send this, since it is equivalent
         * to empty input. So explicitly disallow it, and require that the
         * pattern have some actual content to match.
         */
        if (!c->protocol && !c->host && !c->path && !c->username)
                return;
        for_each_string_list_item(fn, fns)
                if (!access(fn->string, F_OK))
                        rewrite_credential_file(fn->string, c, NULL);
}

static void lookup_credential(const struct string_list *fns, struct credential *c)
{
        struct string_list_item *fn;

        for_each_string_list_item(fn, fns)
                if (parse_credential_file(fn->string, c, print_entry, NULL))
                        return; /* Found credential */
}

int main(int argc, char **argv)
{
        const char * const usage[] = {
                "git credential-store [<options>] <action>",
                NULL
        };
        const char *op;
        struct credential c = CREDENTIAL_INIT;
        struct string_list fns = STRING_LIST_INIT_DUP;
        char *file = NULL;
        struct option options[] = {
                OPT_STRING(0, "file", &file, "path",
                           "fetch and store credentials in <path>"),
                OPT_END()
        };

        umask(077);

        argc = parse_options(argc, (const char **)argv, NULL, options, usage, 0);
        if (argc != 1)
                usage_with_options(usage, options);
        op = argv[0];

        if (file) {
                string_list_append(&fns, file);
        } else {
                if ((file = expand_user_path("~/.git-credentials")))
                        string_list_append_nodup(&fns, file);
                file = xdg_config_home("credentials");
                if (file)
                        string_list_append_nodup(&fns, file);
        }
        if (!fns.nr)
                die("unable to set up default path; use --file");

        if (credential_read(&c, stdin) < 0)
                die("unable to read credential");

        if (!strcmp(op, "get"))
                lookup_credential(&fns, &c);
        else if (!strcmp(op, "erase"))
                remove_credential(&fns, &c);
        else if (!strcmp(op, "store"))
                store_credential(&fns, &c);
        else
                ; /* Ignore unknown operation. */

        string_list_clear(&fns, 0);
        return 0;
}