//
//      aegis - project change supervisor
//      Copyright (C) 1999, 2001-2009, 2012, 2014 Peter Miller
//      Copyright (C) 2008 Walter Franzini
//
//      This program is free software; you can redistribute it and/or modify
//      it under the terms of the GNU General Public License as published by
//      the Free Software Foundation; either version 3 of the License, or
//      (at your option) any later version.
//
//      This program is distributed in the hope that it will be useful,
//      but WITHOUT ANY WARRANTY; without even the implied warranty of
//      MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
//      GNU General Public License for more details.
//
//      You should have received a copy of the GNU General Public License
//      along with this program. If not, see
//      <http://www.gnu.org/licenses/>.
//

#include <common/ac/assert.h>

#include <common/mem.h>
#include <common/trace.h>
#include <libaegis/attribute.h>
#include <libaegis/change.h>
#include <libaegis/change/attributes.h>
#include <libaegis/change/env_set.h>
#include <libaegis/input/base64.h>
#include <libaegis/input/file.h>
#include <libaegis/input/quoted_print.h>
#include <libaegis/os.h>
#include <libaegis/output/file.h>
#include <libaegis/project.h>
#include <libaegis/sub.h>
#include <libaegis/user.h>


void
change_run_history_get_command(change::pointer cp, fstate_src_ty *src,
    string_ty *output_file_name, user_ty::pointer up)
{
    sub_context_ty  *scp;
    string_ty       *hp;
    string_ty       *hfn;
    string_ty       *the_command;
    pconf_ty        *pconf_data;
    string_ty       *name_of_encoded_file;
    output::pointer op;

    trace(("change_run_history_get_command(cp = %p)\n{\n", cp.get()));
    assert(cp->valid());
    assert(src->reference_count >= 1);
    assert(src->file_name);
    assert(src->edit);
    assert(src->edit->revision);
    if (src->edit->encoding == history_version_encoding_none)
        name_of_encoded_file = output_file_name;
    else
        name_of_encoded_file = os_edit_filename(0);
    trace(("file name = \"%s\";\n", src->file_name->str_text));
    trace(("edit number = \"%s\";\n", src->edit->revision->str_text));

    //
    // If enough information is available use the change-set src
    // belongs to for the rest of the processing.
    //
    // Depending on the presence of the edit.uuid field means this
    // feature is available only for project created with 4,26 or
    // later.  We can probably use the roll_forward machinery to
    // locate the change-set responsible of the requested file's
    // revision, however that may have negative memory and speed
    // effects.
    //
    if (src->edit->uuid)
    {
        change::pointer cp2 =
            project_uuid_find(cp->project_get(), src->edit->uuid);
        assert(cp2);
        if (!cp2)
            goto old_behavior;

        //
        // Check for the presence of the history_get_command change's
        // attribute.  If it's missing we proceed with the old behavior.
        //
        if (!change_attributes_find(cp2, HISTORY_GET_COMMAND))
            goto old_behavior;

        cp = cp2;
    }
old_behavior:

    //
    // Inform the user of what we are doing, just in case they can't
    // tell from the file names.  For example, with a base-64 encoded
    // input file and a UUID history file the user has no way of knowing
    // which source file this concerns.
    //
    scp = sub_context_new();
    scp->var_set_string("File_Name", src->file_name);
    scp->var_set_string("Edit", src->edit->revision);
    scp->var_optional("Edit");
    change_error(cp, scp, i18n("history get $filename"));
    sub_context_delete(scp);
    scp = 0;

    //
    // If the edit numbers differ, extract the
    // appropriate edit from the baseline (use the
    // history-get-command) into a file in /tmp
    //
    // Current directory set to the base of the history tree.
    // All of the substitutions described in aesub(5) are available;
    // in addition
    //
    // ${History}
    //      history file
    //
    // ${Edit}
    //      edit number
    //
    // ${Output}
    //      output file
    //
    scp = sub_context_new();
    hfn = project_history_filename_get(cp->project_get(), src);
    trace(("hfn = \"%s\"\n", hfn->str_text));
    sub_var_set_string(scp, "History", hfn);
    str_free(hfn);

    sub_var_set_string(scp, "Edit", src->edit->revision);
    sub_var_set_string(scp, "Output", name_of_encoded_file);

    //
    // Prefer the command stored as change attribute and if not
    // available consult the project configuration.
    //
    the_command = change_attributes_find(cp, HISTORY_GET_COMMAND);
    if (!the_command)
    {
        pconf_data = change_pconf_get(cp, 1);
        the_command = pconf_data->history_get_command;
    }

    if (!the_command)
    {
        sub_context_ty  *scp2;

        assert(pconf_data->errpos);
        scp2 = sub_context_new();
        sub_var_set_string(scp2, "File_Name", pconf_data->errpos);
        sub_var_set_charstar(scp2, "FieLD_Name", "history_get_command");
        change_fatal
        (
            cp,
            scp2,
            i18n("$filename: contains no \"$field_name\" field")
        );
        sub_context_delete(scp2);
    }
    the_command = substitute(scp, cp, the_command);
    trace(("cmd = \"%s\"\n", the_command->str_text));
    sub_context_delete(scp);

    //
    // run the command as the current user
    // (always output is to /tmp)
    //
    change_env_set(cp, 0);
    hp = cp->project_get()->history_path_get();
    up->become_begin();
    os_execute(the_command, OS_EXEC_FLAG_NO_INPUT | OS_EXEC_FLAG_SILENT, hp);
    up->become_end();
    str_free(the_command);

    if (src->edit->encoding == history_version_encoding_none)
    {
        assert(name_of_encoded_file == output_file_name);
        trace(("}\n"));
        return;
    }

    //
    // Decode the file.
    //
    os_become_orig();
    input::pointer ip = input_file::open_text(nstring(name_of_encoded_file));
    op = output_file::binary_open(output_file_name);
    switch (src->edit->encoding)
    {
    case history_version_encoding_none:
        assert(0);
        break;

    case history_version_encoding_quoted_printable:
        ip = input_quoted_printable::create(ip);
        break;

    case history_version_encoding_base64:
        ip = input_base64::create(ip);
        break;
    }
    op << ip;
    ip.reset();
    op.reset();
    os_unlink(name_of_encoded_file);
    os_become_undo();
    str_free(name_of_encoded_file);
    trace(("}\n"));
}


// vim: set ts=8 sw=4 et :