#include "cache.h"
#include "diff.h"
#include "commit.h"
#include "log-tree.h"

void init_log_tree_opt(struct log_tree_opt *opt)
{
        memset(opt, 0, sizeof *opt);
        opt->ignore_merges = 1;
        opt->header_prefix = "";
        opt->commit_format = CMIT_FMT_RAW;
        diff_setup(&opt->diffopt);
}

int log_tree_opt_parse(struct log_tree_opt *opt, const char **av, int ac)
{
        const char *arg;
        int cnt = diff_opt_parse(&opt->diffopt, av, ac);
        if (0 < cnt)
                return cnt;
        arg = *av;
        if (!strcmp(arg, "-r"))
                opt->diffopt.recursive = 1;
        else if (!strcmp(arg, "-t")) {
                opt->diffopt.recursive = 1;
                opt->diffopt.tree_in_recursive = 1;
        }
        else if (!strcmp(arg, "-m"))
                opt->ignore_merges = 0;
        else if (!strcmp(arg, "-c"))
                opt->combine_merges = 1;
        else if (!strcmp(arg, "--cc")) {
                opt->dense_combined_merges = 1;
                opt->combine_merges = 1;
        }
        else if (!strcmp(arg, "-v")) {
                opt->verbose_header = 1;
                opt->header_prefix = "diff-tree ";
        }
        else if (!strncmp(arg, "--pretty", 8)) {
                opt->verbose_header = 1;
                opt->header_prefix = "diff-tree ";
                opt->commit_format = get_commit_format(arg+8);
        }
        else if (!strcmp(arg, "--root"))
                opt->show_root_diff = 1;
        else if (!strcmp(arg, "--no-commit-id"))
                opt->no_commit_id = 1;
        else if (!strcmp(arg, "--always"))
                opt->always_show_header = 1;
        else
                return 0;
        return 1;
}

int log_tree_diff_flush(struct log_tree_opt *opt)
{
        diffcore_std(&opt->diffopt);
        if (diff_queue_is_empty()) {
                int saved_fmt = opt->diffopt.output_format;
                opt->diffopt.output_format = DIFF_FORMAT_NO_OUTPUT;
                diff_flush(&opt->diffopt);
                opt->diffopt.output_format = saved_fmt;
                return 0;
        }
        if (opt->header) {
                if (!opt->no_commit_id)
                        printf("%s%c", opt->header,
                               opt->diffopt.line_termination);
                opt->header = NULL;
        }
        diff_flush(&opt->diffopt);
        return 1;
}

static int diff_root_tree(struct log_tree_opt *opt,
                          const unsigned char *new, const char *base)
{
        int retval;
        void *tree;
        struct tree_desc empty, real;

        tree = read_object_with_reference(new, tree_type, &real.size, NULL);
        if (!tree)
                die("unable to read root tree (%s)", sha1_to_hex(new));
        real.buf = tree;

        empty.buf = "";
        empty.size = 0;
        retval = diff_tree(&empty, &real, base, &opt->diffopt);
        free(tree);
        log_tree_diff_flush(opt);
        return retval;
}

static const char *generate_header(struct log_tree_opt *opt,
                                   const unsigned char *commit_sha1,
                                   const unsigned char *parent_sha1,
                                   const struct commit *commit)
{
        static char this_header[16384];
        int offset;
        unsigned long len;
        int abbrev = opt->diffopt.abbrev;
        const char *msg = commit->buffer;

        if (!opt->verbose_header)
                return sha1_to_hex(commit_sha1);

        len = strlen(msg);

        offset = sprintf(this_header, "%s%s ",
                         opt->header_prefix,
                         diff_unique_abbrev(commit_sha1, abbrev));
        if (commit_sha1 != parent_sha1)
                offset += sprintf(this_header + offset, "(from %s)\n",
                                  parent_sha1
                                  ? diff_unique_abbrev(parent_sha1, abbrev)
                                  : "root");
        else
                offset += sprintf(this_header + offset, "(from parents)\n");
        offset += pretty_print_commit(opt->commit_format, commit, len,
                                      this_header + offset,
                                      sizeof(this_header) - offset, abbrev);
        if (opt->always_show_header) {
                puts(this_header);
                return NULL;
        }
        return this_header;
}

static int do_diff_combined(struct log_tree_opt *opt, struct commit *commit)
{
        unsigned const char *sha1 = commit->object.sha1;

        opt->header = generate_header(opt, sha1, sha1, commit);
        opt->header = diff_tree_combined_merge(sha1, opt->header,
                                                opt->dense_combined_merges,
                                                &opt->diffopt);
        if (!opt->header && opt->verbose_header)
                opt->header_prefix = "\ndiff-tree ";
        return 0;
}

int log_tree_commit(struct log_tree_opt *opt, struct commit *commit)
{
        struct commit_list *parents;
        unsigned const char *sha1 = commit->object.sha1;

        /* Root commit? */
        if (opt->show_root_diff && !commit->parents) {
                opt->header = generate_header(opt, sha1, NULL, commit);
                diff_root_tree(opt, sha1, "");
        }

        /* More than one parent? */
        if (commit->parents && commit->parents->next) {
                if (opt->ignore_merges)
                        return 0;
                else if (opt->combine_merges)
                        return do_diff_combined(opt, commit);
        }

        for (parents = commit->parents; parents; parents = parents->next) {
                struct commit *parent = parents->item;
                unsigned const char *psha1 = parent->object.sha1;
                opt->header = generate_header(opt, sha1, psha1, commit);
                diff_tree_sha1(psha1, sha1, "", &opt->diffopt);
                log_tree_diff_flush(opt);               

                if (!opt->header && opt->verbose_header)
                        opt->header_prefix = "\ndiff-tree ";
        }
        return 0;
}