#include "builtin.h"
#include "cache.h"
#include "exec_cmd.h"
#include "help.h"
#include "quote.h"
#include "run-command.h"
#include "commit.h"

const char git_usage_string[] =
        "git [--version] [--help] [-c name=value]\n"
        "           [--exec-path[=<path>]] [--html-path] [--man-path] [--info-path]\n"
        "           [-p|--paginate|--no-pager] [--no-replace-objects] [--bare]\n"
        "           [--git-dir=<path>] [--work-tree=<path>] [--namespace=<name>]\n"
        "           <command> [<args>]";

const char git_more_info_string[] =
        N_("'git help -a' and 'git help -g' lists available subcommands and some\n"
           "concept guides. See 'git help <command>' or 'git help <concept>'\n"
           "to read about a specific subcommand or concept.");

static struct startup_info git_startup_info;
static int use_pager = -1;

static void commit_pager_choice(void) {
        switch (use_pager) {
        case 0:
                setenv("GIT_PAGER", "cat", 1);
                break;
        case 1:
                setup_pager();
                break;
        default:
                break;
        }
}

static int handle_options(const char ***argv, int *argc, int *envchanged)
{
        const char **orig_argv = *argv;

        while (*argc > 0) {
                const char *cmd = (*argv)[0];
                if (cmd[0] != '-')
                        break;

                /*
                 * For legacy reasons, the "version" and "help"
                 * commands can be written with "--" prepended
                 * to make them look like flags.
                 */
                if (!strcmp(cmd, "--help") || !strcmp(cmd, "--version"))
                        break;

                /*
                 * Check remaining flags.
                 */
                if (!prefixcmp(cmd, "--exec-path")) {
                        cmd += 11;
                        if (*cmd == '=')
                                git_set_argv_exec_path(cmd + 1);
                        else {
                                puts(git_exec_path());
                                exit(0);
                        }
                } else if (!strcmp(cmd, "--html-path")) {
                        puts(system_path(GIT_HTML_PATH));
                        exit(0);
                } else if (!strcmp(cmd, "--man-path")) {
                        puts(system_path(GIT_MAN_PATH));
                        exit(0);
                } else if (!strcmp(cmd, "--info-path")) {
                        puts(system_path(GIT_INFO_PATH));
                        exit(0);
                } else if (!strcmp(cmd, "-p") || !strcmp(cmd, "--paginate")) {
                        use_pager = 1;
                } else if (!strcmp(cmd, "--no-pager")) {
                        use_pager = 0;
                        if (envchanged)
                                *envchanged = 1;
                } else if (!strcmp(cmd, "--no-replace-objects")) {
                        read_replace_refs = 0;
                        setenv(NO_REPLACE_OBJECTS_ENVIRONMENT, "1", 1);
                        if (envchanged)
                                *envchanged = 1;
                } else if (!strcmp(cmd, "--git-dir")) {
                        if (*argc < 2) {
                                fprintf(stderr, "No directory given for --git-dir.\n" );
                                usage(git_usage_string);
                        }
                        setenv(GIT_DIR_ENVIRONMENT, (*argv)[1], 1);
                        if (envchanged)
                                *envchanged = 1;
                        (*argv)++;
                        (*argc)--;
                } else if (!prefixcmp(cmd, "--git-dir=")) {
                        setenv(GIT_DIR_ENVIRONMENT, cmd + 10, 1);
                        if (envchanged)
                                *envchanged = 1;
                } else if (!strcmp(cmd, "--namespace")) {
                        if (*argc < 2) {
                                fprintf(stderr, "No namespace given for --namespace.\n" );
                                usage(git_usage_string);
                        }
                        setenv(GIT_NAMESPACE_ENVIRONMENT, (*argv)[1], 1);
                        if (envchanged)
                                *envchanged = 1;
                        (*argv)++;
                        (*argc)--;
                } else if (!prefixcmp(cmd, "--namespace=")) {
                        setenv(GIT_NAMESPACE_ENVIRONMENT, cmd + 12, 1);
                        if (envchanged)
                                *envchanged = 1;
                } else if (!strcmp(cmd, "--work-tree")) {
                        if (*argc < 2) {
                                fprintf(stderr, "No directory given for --work-tree.\n" );
                                usage(git_usage_string);
                        }
                        setenv(GIT_WORK_TREE_ENVIRONMENT, (*argv)[1], 1);
                        if (envchanged)
                                *envchanged = 1;
                        (*argv)++;
                        (*argc)--;
                } else if (!prefixcmp(cmd, "--work-tree=")) {
                        setenv(GIT_WORK_TREE_ENVIRONMENT, cmd + 12, 1);
                        if (envchanged)
                                *envchanged = 1;
                } else if (!strcmp(cmd, "--bare")) {
                        static char git_dir[PATH_MAX+1];
                        is_bare_repository_cfg = 1;
                        setenv(GIT_DIR_ENVIRONMENT, getcwd(git_dir, sizeof(git_dir)), 0);
                        setenv(GIT_IMPLICIT_WORK_TREE_ENVIRONMENT, "0", 1);
                        if (envchanged)
                                *envchanged = 1;
                } else if (!strcmp(cmd, "-c")) {
                        if (*argc < 2) {
                                fprintf(stderr, "-c expects a configuration string\n" );
                                usage(git_usage_string);
                        }
                        git_config_push_parameter((*argv)[1]);
                        (*argv)++;
                        (*argc)--;
                } else if (!strcmp(cmd, "--literal-pathspecs")) {
                        setenv(GIT_LITERAL_PATHSPECS_ENVIRONMENT, "1", 1);
                        if (envchanged)
                                *envchanged = 1;
                } else if (!strcmp(cmd, "--no-literal-pathspecs")) {
                        setenv(GIT_LITERAL_PATHSPECS_ENVIRONMENT, "0", 1);
                        if (envchanged)
                                *envchanged = 1;
                } else if (!strcmp(cmd, "--shallow-file")) {
                        (*argv)++;
                        (*argc)--;
                        set_alternate_shallow_file((*argv)[0]);
                        if (envchanged)
                                *envchanged = 1;
                } else {
                        fprintf(stderr, "Unknown option: %s\n", cmd);
                        usage(git_usage_string);
                }

                (*argv)++;
                (*argc)--;
        }
        return (*argv) - orig_argv;
}

static int handle_alias(int *argcp, const char ***argv)
{
        int envchanged = 0, ret = 0, saved_errno = errno;
        const char *subdir;
        int count, option_count;
        const char **new_argv;
        const char *alias_command;
        char *alias_string;
        int unused_nongit;

        subdir = setup_git_directory_gently(&unused_nongit);

        alias_command = (*argv)[0];
        alias_string = alias_lookup(alias_command);
        if (alias_string) {
                if (alias_string[0] == '!') {
                        const char **alias_argv;
                        int argc = *argcp, i;

                        commit_pager_choice();

                        /* build alias_argv */
                        alias_argv = xmalloc(sizeof(*alias_argv) * (argc + 1));
                        alias_argv[0] = alias_string + 1;
                        for (i = 1; i < argc; ++i)
                                alias_argv[i] = (*argv)[i];
                        alias_argv[argc] = NULL;

                        ret = run_command_v_opt(alias_argv, RUN_USING_SHELL);
                        if (ret >= 0)   /* normal exit */
                                exit(ret);

                        die_errno("While expanding alias '%s': '%s'",
                            alias_command, alias_string + 1);
                }
                count = split_cmdline(alias_string, &new_argv);
                if (count < 0)
                        die("Bad alias.%s string: %s", alias_command,
                            split_cmdline_strerror(count));
                option_count = handle_options(&new_argv, &count, &envchanged);
                if (envchanged)
                        die("alias '%s' changes environment variables\n"
                                 "You can use '!git' in the alias to do this.",
                                 alias_command);
                memmove(new_argv - option_count, new_argv,
                                count * sizeof(char *));
                new_argv -= option_count;

                if (count < 1)
                        die("empty alias for %s", alias_command);

                if (!strcmp(alias_command, new_argv[0]))
                        die("recursive alias: %s", alias_command);

                trace_argv_printf(new_argv,
                                  "trace: alias expansion: %s =>",
                                  alias_command);

                new_argv = xrealloc(new_argv, sizeof(char *) *
                                    (count + *argcp));
                /* insert after command name */
                memcpy(new_argv + count, *argv + 1, sizeof(char *) * *argcp);

                *argv = new_argv;
                *argcp += count - 1;

                ret = 1;
        }

        if (subdir && chdir(subdir))
                die_errno("Cannot change to '%s'", subdir);

        errno = saved_errno;

        return ret;
}

#define RUN_SETUP               (1<<0)
#define RUN_SETUP_GENTLY        (1<<1)
#define USE_PAGER               (1<<2)
/*
 * require working tree to be present -- anything uses this needs
 * RUN_SETUP for reading from the configuration file.
 */
#define NEED_WORK_TREE          (1<<3)

struct cmd_struct {
        const char *cmd;
        int (*fn)(int, const char **, const char *);
        int option;
};

static int run_builtin(struct cmd_struct *p, int argc, const char **argv)
{
        int status, help;
        struct stat st;
        const char *prefix;

        prefix = NULL;
        help = argc == 2 && !strcmp(argv[1], "-h");
        if (!help) {
                if (p->option & RUN_SETUP)
                        prefix = setup_git_directory();
                if (p->option & RUN_SETUP_GENTLY) {
                        int nongit_ok;
                        prefix = setup_git_directory_gently(&nongit_ok);
                }

                if (use_pager == -1 && p->option & (RUN_SETUP | RUN_SETUP_GENTLY))
                        use_pager = check_pager_config(p->cmd);
                if (use_pager == -1 && p->option & USE_PAGER)
                        use_pager = 1;

                if ((p->option & (RUN_SETUP | RUN_SETUP_GENTLY)) &&
                    startup_info->have_repository) /* get_git_dir() may set up repo, avoid that */
                        trace_repo_setup(prefix);
        }
        commit_pager_choice();

        if (!help && p->option & NEED_WORK_TREE)
                setup_work_tree();

        trace_argv_printf(argv, "trace: built-in: git");

        status = p->fn(argc, argv, prefix);
        if (status)
                return status;

        /* Somebody closed stdout? */
        if (fstat(fileno(stdout), &st))
                return 0;
        /* Ignore write errors for pipes and sockets.. */
        if (S_ISFIFO(st.st_mode) || S_ISSOCK(st.st_mode))
                return 0;

        /* Check for ENOSPC and EIO errors.. */
        if (fflush(stdout))
                die_errno("write failure on standard output");
        if (ferror(stdout))
                die("unknown write failure on standard output");
        if (fclose(stdout))
                die_errno("close failed on standard output");
        return 0;
}

static void handle_internal_command(int argc, const char **argv)
{
        const char *cmd = argv[0];
        static struct cmd_struct commands[] = {
                { "add", cmd_add, RUN_SETUP | NEED_WORK_TREE },
                { "annotate", cmd_annotate, RUN_SETUP },
                { "apply", cmd_apply, RUN_SETUP_GENTLY },
                { "archive", cmd_archive },
                { "bisect--helper", cmd_bisect__helper, RUN_SETUP },
                { "blame", cmd_blame, RUN_SETUP },
                { "branch", cmd_branch, RUN_SETUP },
                { "bundle", cmd_bundle, RUN_SETUP_GENTLY },
                { "cat-file", cmd_cat_file, RUN_SETUP },
                { "check-attr", cmd_check_attr, RUN_SETUP },
                { "check-ignore", cmd_check_ignore, RUN_SETUP | NEED_WORK_TREE },
                { "check-mailmap", cmd_check_mailmap, RUN_SETUP },
                { "check-ref-format", cmd_check_ref_format },
                { "checkout", cmd_checkout, RUN_SETUP | NEED_WORK_TREE },
                { "checkout-index", cmd_checkout_index,
                        RUN_SETUP | NEED_WORK_TREE},
                { "cherry", cmd_cherry, RUN_SETUP },
                { "cherry-pick", cmd_cherry_pick, RUN_SETUP | NEED_WORK_TREE },
                { "clean", cmd_clean, RUN_SETUP | NEED_WORK_TREE },
                { "clone", cmd_clone },
                { "column", cmd_column, RUN_SETUP_GENTLY },
                { "commit", cmd_commit, RUN_SETUP | NEED_WORK_TREE },
                { "commit-tree", cmd_commit_tree, RUN_SETUP },
                { "config", cmd_config, RUN_SETUP_GENTLY },
                { "count-objects", cmd_count_objects, RUN_SETUP },
                { "credential", cmd_credential, RUN_SETUP_GENTLY },
                { "describe", cmd_describe, RUN_SETUP },
                { "diff", cmd_diff },
                { "diff-files", cmd_diff_files, RUN_SETUP | NEED_WORK_TREE },
                { "diff-index", cmd_diff_index, RUN_SETUP },
                { "diff-tree", cmd_diff_tree, RUN_SETUP },
                { "fast-export", cmd_fast_export, RUN_SETUP },
                { "fetch", cmd_fetch, RUN_SETUP },
                { "fetch-pack", cmd_fetch_pack, RUN_SETUP },
                { "fmt-merge-msg", cmd_fmt_merge_msg, RUN_SETUP },
                { "for-each-ref", cmd_for_each_ref, RUN_SETUP },
                { "format-patch", cmd_format_patch, RUN_SETUP },
                { "fsck", cmd_fsck, RUN_SETUP },
                { "fsck-objects", cmd_fsck, RUN_SETUP },
                { "gc", cmd_gc, RUN_SETUP },
                { "get-tar-commit-id", cmd_get_tar_commit_id },
                { "grep", cmd_grep, RUN_SETUP_GENTLY },
                { "hash-object", cmd_hash_object },
                { "help", cmd_help },
                { "index-pack", cmd_index_pack, RUN_SETUP_GENTLY },
                { "init", cmd_init_db },
                { "init-db", cmd_init_db },
                { "log", cmd_log, RUN_SETUP },
                { "ls-files", cmd_ls_files, RUN_SETUP },
                { "ls-remote", cmd_ls_remote, RUN_SETUP_GENTLY },
                { "ls-tree", cmd_ls_tree, RUN_SETUP },
                { "mailinfo", cmd_mailinfo },
                { "mailsplit", cmd_mailsplit },
                { "merge", cmd_merge, RUN_SETUP | NEED_WORK_TREE },
                { "merge-base", cmd_merge_base, RUN_SETUP },
                { "merge-file", cmd_merge_file, RUN_SETUP_GENTLY },
                { "merge-index", cmd_merge_index, RUN_SETUP },
                { "merge-ours", cmd_merge_ours, RUN_SETUP },
                { "merge-recursive", cmd_merge_recursive, RUN_SETUP | NEED_WORK_TREE },
                { "merge-recursive-ours", cmd_merge_recursive, RUN_SETUP | NEED_WORK_TREE },
                { "merge-recursive-theirs", cmd_merge_recursive, RUN_SETUP | NEED_WORK_TREE },
                { "merge-subtree", cmd_merge_recursive, RUN_SETUP | NEED_WORK_TREE },
                { "merge-tree", cmd_merge_tree, RUN_SETUP },
                { "mktag", cmd_mktag, RUN_SETUP },
                { "mktree", cmd_mktree, RUN_SETUP },
                { "mv", cmd_mv, RUN_SETUP | NEED_WORK_TREE },
                { "name-rev", cmd_name_rev, RUN_SETUP },
                { "notes", cmd_notes, RUN_SETUP },
                { "pack-objects", cmd_pack_objects, RUN_SETUP },
                { "pack-redundant", cmd_pack_redundant, RUN_SETUP },
                { "pack-refs", cmd_pack_refs, RUN_SETUP },
                { "patch-id", cmd_patch_id },
                { "peek-remote", cmd_ls_remote, RUN_SETUP_GENTLY },
                { "pickaxe", cmd_blame, RUN_SETUP },
                { "prune", cmd_prune, RUN_SETUP },
                { "prune-packed", cmd_prune_packed, RUN_SETUP },
                { "push", cmd_push, RUN_SETUP },
                { "read-tree", cmd_read_tree, RUN_SETUP },
                { "receive-pack", cmd_receive_pack },
                { "reflog", cmd_reflog, RUN_SETUP },
                { "remote", cmd_remote, RUN_SETUP },
                { "remote-ext", cmd_remote_ext },
                { "remote-fd", cmd_remote_fd },
                { "replace", cmd_replace, RUN_SETUP },
                { "repo-config", cmd_repo_config, RUN_SETUP_GENTLY },
                { "rerere", cmd_rerere, RUN_SETUP },
                { "reset", cmd_reset, RUN_SETUP },
                { "rev-list", cmd_rev_list, RUN_SETUP },
                { "rev-parse", cmd_rev_parse },
                { "revert", cmd_revert, RUN_SETUP | NEED_WORK_TREE },
                { "rm", cmd_rm, RUN_SETUP },
                { "send-pack", cmd_send_pack, RUN_SETUP },
                { "shortlog", cmd_shortlog, RUN_SETUP_GENTLY | USE_PAGER },
                { "show", cmd_show, RUN_SETUP },
                { "show-branch", cmd_show_branch, RUN_SETUP },
                { "show-ref", cmd_show_ref, RUN_SETUP },
                { "stage", cmd_add, RUN_SETUP | NEED_WORK_TREE },
                { "status", cmd_status, RUN_SETUP | NEED_WORK_TREE },
                { "stripspace", cmd_stripspace },
                { "symbolic-ref", cmd_symbolic_ref, RUN_SETUP },
                { "tag", cmd_tag, RUN_SETUP },
                { "tar-tree", cmd_tar_tree },
                { "unpack-file", cmd_unpack_file, RUN_SETUP },
                { "unpack-objects", cmd_unpack_objects, RUN_SETUP },
                { "update-index", cmd_update_index, RUN_SETUP },
                { "update-ref", cmd_update_ref, RUN_SETUP },
                { "update-server-info", cmd_update_server_info, RUN_SETUP },
                { "upload-archive", cmd_upload_archive },
                { "upload-archive--writer", cmd_upload_archive_writer },
                { "var", cmd_var, RUN_SETUP_GENTLY },
                { "verify-pack", cmd_verify_pack },
                { "verify-tag", cmd_verify_tag, RUN_SETUP },
                { "version", cmd_version },
                { "whatchanged", cmd_whatchanged, RUN_SETUP },
                { "write-tree", cmd_write_tree, RUN_SETUP },
        };
        int i;
        static const char ext[] = STRIP_EXTENSION;

        if (sizeof(ext) > 1) {
                i = strlen(argv[0]) - strlen(ext);
                if (i > 0 && !strcmp(argv[0] + i, ext)) {
                        char *argv0 = xstrdup(argv[0]);
                        argv[0] = cmd = argv0;
                        argv0[i] = '\0';
                }
        }

        /* Turn "git cmd --help" into "git help cmd" */
        if (argc > 1 && !strcmp(argv[1], "--help")) {
                argv[1] = argv[0];
                argv[0] = cmd = "help";
        }

        for (i = 0; i < ARRAY_SIZE(commands); i++) {
                struct cmd_struct *p = commands+i;
                if (strcmp(p->cmd, cmd))
                        continue;
                exit(run_builtin(p, argc, argv));
        }
}

static void execv_dashed_external(const char **argv)
{
        struct strbuf cmd = STRBUF_INIT;
        const char *tmp;
        int status;

        if (use_pager == -1)
                use_pager = check_pager_config(argv[0]);
        commit_pager_choice();

        strbuf_addf(&cmd, "git-%s", argv[0]);

        /*
         * argv[0] must be the git command, but the argv array
         * belongs to the caller, and may be reused in
         * subsequent loop iterations. Save argv[0] and
         * restore it on error.
         */
        tmp = argv[0];
        argv[0] = cmd.buf;

        trace_argv_printf(argv, "trace: exec:");

        /*
         * if we fail because the command is not found, it is
         * OK to return. Otherwise, we just pass along the status code.
         */
        status = run_command_v_opt(argv, RUN_SILENT_EXEC_FAILURE | RUN_CLEAN_ON_EXIT);
        if (status >= 0 || errno != ENOENT)
                exit(status);

        argv[0] = tmp;

        strbuf_release(&cmd);
}

static int run_argv(int *argcp, const char ***argv)
{
        int done_alias = 0;

        while (1) {
                /* See if it's an internal command */
                handle_internal_command(*argcp, *argv);

                /* .. then try the external ones */
                execv_dashed_external(*argv);

                /* It could be an alias -- this works around the insanity
                 * of overriding "git log" with "git show" by having
                 * alias.log = show
                 */
                if (done_alias || !handle_alias(argcp, argv))
                        break;
                done_alias = 1;
        }

        return done_alias;
}


int main(int argc, char **av)
{
        const char **argv = (const char **) av;
        const char *cmd;

        startup_info = &git_startup_info;

        cmd = git_extract_argv0_path(argv[0]);
        if (!cmd)
                cmd = "git-help";

        /*
         * Always open file descriptors 0/1/2 to avoid clobbering files
         * in die().  It also avoids messing up when the pipes are dup'ed
         * onto stdin/stdout/stderr in the child processes we spawn.
         */
        sanitize_stdfds();

        git_setup_gettext();

        /*
         * "git-xxxx" is the same as "git xxxx", but we obviously:
         *
         *  - cannot take flags in between the "git" and the "xxxx".
         *  - cannot execute it externally (since it would just do
         *    the same thing over again)
         *
         * So we just directly call the internal command handler, and
         * die if that one cannot handle it.
         */
        if (!prefixcmp(cmd, "git-")) {
                cmd += 4;
                argv[0] = cmd;
                handle_internal_command(argc, argv);
                die("cannot handle %s internally", cmd);
        }

        /* Look for flags.. */
        argv++;
        argc--;
        handle_options(&argv, &argc, NULL);
        if (argc > 0) {
                if (!prefixcmp(argv[0], "--"))
                        argv[0] += 2;
        } else {
                /* The user didn't specify a command; give them help */
                commit_pager_choice();
                printf("usage: %s\n\n", git_usage_string);
                list_common_cmds_help();
                printf("\n%s\n", _(git_more_info_string));
                exit(1);
        }
        cmd = argv[0];

        /*
         * We use PATH to find git commands, but we prepend some higher
         * precedence paths: the "--exec-path" option, the GIT_EXEC_PATH
         * environment, and the $(gitexecdir) from the Makefile at build
         * time.
         */
        setup_path();

        while (1) {
                static int done_help = 0;
                static int was_alias = 0;
                was_alias = run_argv(&argc, &argv);
                if (errno != ENOENT)
                        break;
                if (was_alias) {
                        fprintf(stderr, "Expansion of alias '%s' failed; "
                                "'%s' is not a git command\n",
                                cmd, argv[0]);
                        exit(1);
                }
                if (!done_help) {
                        cmd = argv[0] = help_unknown_cmd(cmd);
                        done_help = 1;
                } else
                        break;
        }

        fprintf(stderr, "Failed to run command '%s': %s\n",
                cmd, strerror(errno));

        return 1;
}