/*
 * "diff --no-index" support
 * Copyright (c) 2007 by Johannes Schindelin
 * Copyright (c) 2008 by Junio C Hamano
 */

#include "cache.h"
#include "color.h"
#include "commit.h"
#include "blob.h"
#include "tag.h"
#include "diff.h"
#include "diffcore.h"
#include "revision.h"
#include "log-tree.h"
#include "builtin.h"
#include "path-list.h"

static int read_directory(const char *path, struct path_list *list)
{
        DIR *dir;
        struct dirent *e;

        if (!(dir = opendir(path)))
                return error("Could not open directory %s", path);

        while ((e = readdir(dir)))
                if (strcmp(".", e->d_name) && strcmp("..", e->d_name))
                        path_list_insert(e->d_name, list);

        closedir(dir);
        return 0;
}

static int get_mode(const char *path, int *mode)
{
        struct stat st;

        if (!path || !strcmp(path, "/dev/null"))
                *mode = 0;
        else if (!strcmp(path, "-"))
                *mode = create_ce_mode(0666);
        else if (stat(path, &st))
                return error("Could not access '%s'", path);
        else
                *mode = st.st_mode;
        return 0;
}

static int queue_diff(struct diff_options *o,
                const char *name1, const char *name2)
{
        int mode1 = 0, mode2 = 0;

        if (get_mode(name1, &mode1) || get_mode(name2, &mode2))
                return -1;

        if (mode1 && mode2 && S_ISDIR(mode1) != S_ISDIR(mode2))
                return error("file/directory conflict: %s, %s", name1, name2);

        if (S_ISDIR(mode1) || S_ISDIR(mode2)) {
                char buffer1[PATH_MAX], buffer2[PATH_MAX];
                struct path_list p1 = {NULL, 0, 0, 1}, p2 = {NULL, 0, 0, 1};
                int len1 = 0, len2 = 0, i1, i2, ret = 0;

                if (name1 && read_directory(name1, &p1))
                        return -1;
                if (name2 && read_directory(name2, &p2)) {
                        path_list_clear(&p1, 0);
                        return -1;
                }

                if (name1) {
                        len1 = strlen(name1);
                        if (len1 > 0 && name1[len1 - 1] == '/')
                                len1--;
                        memcpy(buffer1, name1, len1);
                        buffer1[len1++] = '/';
                }

                if (name2) {
                        len2 = strlen(name2);
                        if (len2 > 0 && name2[len2 - 1] == '/')
                                len2--;
                        memcpy(buffer2, name2, len2);
                        buffer2[len2++] = '/';
                }

                for (i1 = i2 = 0; !ret && (i1 < p1.nr || i2 < p2.nr); ) {
                        const char *n1, *n2;
                        int comp;

                        if (i1 == p1.nr)
                                comp = 1;
                        else if (i2 == p2.nr)
                                comp = -1;
                        else
                                comp = strcmp(p1.items[i1].path,
                                        p2.items[i2].path);

                        if (comp > 0)
                                n1 = NULL;
                        else {
                                n1 = buffer1;
                                strncpy(buffer1 + len1, p1.items[i1++].path,
                                                PATH_MAX - len1);
                        }

                        if (comp < 0)
                                n2 = NULL;
                        else {
                                n2 = buffer2;
                                strncpy(buffer2 + len2, p2.items[i2++].path,
                                                PATH_MAX - len2);
                        }

                        ret = queue_diff(o, n1, n2);
                }
                path_list_clear(&p1, 0);
                path_list_clear(&p2, 0);

                return ret;
        } else {
                struct diff_filespec *d1, *d2;

                if (DIFF_OPT_TST(o, REVERSE_DIFF)) {
                        unsigned tmp;
                        const char *tmp_c;
                        tmp = mode1; mode1 = mode2; mode2 = tmp;
                        tmp_c = name1; name1 = name2; name2 = tmp_c;
                }

                if (!name1)
                        name1 = "/dev/null";
                if (!name2)
                        name2 = "/dev/null";
                d1 = alloc_filespec(name1);
                d2 = alloc_filespec(name2);
                fill_filespec(d1, null_sha1, mode1);
                fill_filespec(d2, null_sha1, mode2);

                diff_queue(&diff_queued_diff, d1, d2);
                return 0;
        }
}

void diff_no_index(struct rev_info *revs,
                   int argc, const char **argv,
                   int nongit, const char *prefix)
{
        int i;
        int no_index = 0;
        unsigned options = 0;

        /* Were we asked to do --no-index explicitly? */
        for (i = 1; i < argc; i++) {
                if (!strcmp(argv[i], "--"))
                        return;
                if (!strcmp(argv[i], "--no-index"))
                        no_index = 1;
                if (argv[i][0] != '-')
                        break;
        }

        /*
         * No explicit --no-index, but "git diff --opts A B" outside
         * a git repository is a cute hack to support.
         */
        if (!no_index && !nongit)
                return;

        if (argc != i + 2)
                die("git diff %s takes two paths",
                    no_index ? "--no-index" : "[--no-index]");

        diff_setup(&revs->diffopt);
        if (!revs->diffopt.output_format)
                revs->diffopt.output_format = DIFF_FORMAT_PATCH;
        for (i = 1; i < argc - 2; ) {
                int j;
                if (!strcmp(argv[i], "--no-index"))
                        i++;
                else if (!strcmp(argv[1], "-q"))
                        options |= DIFF_SILENT_ON_REMOVED;
                else {
                        j = diff_opt_parse(&revs->diffopt, argv + i, argc - i);
                        if (!j)
                                die("invalid diff option/value: %s", argv[i]);
                        i += j;
                }
        }

        if (prefix) {
                int len = strlen(prefix);

                revs->diffopt.paths = xcalloc(2, sizeof(char*));
                for (i = 0; i < 2; i++) {
                        const char *p = argv[argc - 2 + i];
                        /*
                         * stdin should be spelled as '-'; if you have
                         * path that is '-', spell it as ./-.
                         */
                        p = (strcmp(p, "-")
                             ? xstrdup(prefix_filename(prefix, len, p))
                             : p);
                        revs->diffopt.paths[i] = p;
                }
        }
        else
                revs->diffopt.paths = argv + argc - 2;
        revs->diffopt.nr_paths = 2;

        DIFF_OPT_SET(&revs->diffopt, EXIT_WITH_STATUS);
        DIFF_OPT_SET(&revs->diffopt, NO_INDEX);

        revs->max_count = -2;
        if (diff_setup_done(&revs->diffopt) < 0)
                die("diff_setup_done failed");

        if (queue_diff(&revs->diffopt, revs->diffopt.paths[0],
                       revs->diffopt.paths[1]))
                exit(1);
        diffcore_std(&revs->diffopt);
        diff_flush(&revs->diffopt);

        /*
         * The return code for --no-index imitates diff(1):
         * 0 = no changes, 1 = changes, else error
         */
        exit(revs->diffopt.found_changes);
}