/* Copyright (c) 2006-2025 Jonas Fonseca <jonas.fonseca@gmail.com>
 *
 * 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 2 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.
 */

#include "tig/tree.h"
#include "tig/util.h"
#include "tig/repo.h"
#include "tig/io.h"
#include "tig/parse.h"
#include "tig/options.h"
#include "tig/display.h"
#include "tig/view.h"
#include "tig/draw.h"
#include "tig/blob.h"

/* The top of the path stack. */
static struct view_history tree_view_history = { sizeof(char *) };

static void
pop_tree_stack_entry(struct position *position)
{
	char *path_position = NULL;

	pop_view_history_state(&tree_view_history, position, &path_position);
	path_position[0] = 0;
}

static void
push_tree_stack_entry(struct view *view, const char *name, struct position *position)
{
	size_t pathlen = strlen(view->env->directory);
	char *path_position = view->env->directory + pathlen;
	struct view_state *state = push_view_history_state(&tree_view_history, position, &path_position);

	if (!state)
		return;

	if (!string_format_from(view->env->directory, &pathlen, "%s/", name)) {
		pop_tree_stack_entry(NULL);
		return;
	}

	clear_position(position);
}

/* Parse output from git-ls-tree(1):
 *
 * 100644 blob 95925677ca47beb0b8cce7c0e0011bcc3f61470f  213045	tig.c
 */

#define tree_path_is_parent(path)	(!strcmp("..", (path)))

struct tree_entry {
	char id[SIZEOF_REV];
	char commit[SIZEOF_REV];
	mode_t mode;
	struct time time;		/* Date from the author ident. */
	const struct ident *author;	/* Author of the commit. */
	unsigned long size;
	char name[1];
};

struct tree_state {
	char commit[SIZEOF_REV];
	const struct ident *author;
	struct time author_time;
	bool read_date;
};

static const char *
tree_path(const struct line *line)
{
	return ((struct tree_entry *) line->data)->name;
}

static int
tree_compare_entry(const struct line *line1, const struct line *line2)
{
	if (line1->type != line2->type)
		return line1->type == LINE_DIRECTORY ? -1 : 1;
	return strcmp(tree_path(line1), tree_path(line2));
}

static bool
tree_get_column_data(struct view *view, const struct line *line, struct view_column_data *column_data)
{
	const struct tree_entry *entry = line->data;

	if (line->type == LINE_HEADER)
		return false;

	column_data->author = entry->author;
	column_data->date = &entry->time;
	if (line->type != LINE_DIRECTORY)
		column_data->file_size = &entry->size;
	column_data->id = entry->commit;
	column_data->mode = &entry->mode;
	column_data->file_name = entry->name;

	return true;
}


static struct line *
tree_entry(struct view *view, enum line_type type, const char *path,
	   const char *mode, const char *id, unsigned long size)
{
	bool custom = type == LINE_HEADER || tree_path_is_parent(path);
	struct tree_entry *entry;
	struct line *line = add_line_alloc(view, &entry, type, strlen(path), custom);

	if (!line)
		return NULL;

	strcpy(entry->name, path);
	if (mode)
		entry->mode = strtoul(mode, NULL, 8);
	if (id)
		string_copy_rev(entry->id, id);
	entry->size = size;

	return line;
}

static bool
tree_read_date(struct view *view, struct buffer *buf, struct tree_state *state)
{
	char *text = buf ? buf->data : NULL;
	struct view_column *column = get_view_column(view, VIEW_COLUMN_DATE);
	bool use_author_date = column && column->opt.date.use_author;

	if (!text && state->read_date) {
		state->read_date = false;
		return true;

	} else if (!text) {
		/* Find next entry to process */
		const char *log_file[] = {
			"git", "log", encoding_arg, "--no-color", "--pretty=raw",
				"--cc", "--raw", view->ops->id, "--", "%(directory)", NULL
		};

		if (!view->lines) {
			tree_entry(view, LINE_HEADER, view->env->directory, NULL, NULL, 0);
			tree_entry(view, LINE_DIRECTORY, "..", "040000", view->ref, 0);
			report("Tree is empty");
			return true;
		}

		if (begin_update(view, repo.exec_dir, log_file, OPEN_EXTRA) != SUCCESS) {
			report("Failed to load tree data");
			return true;
		}

		state->read_date = true;
		return false;

	} else if (*text == 'c' && get_line_type(text) == LINE_COMMIT) {
		string_copy_rev_from_commit_line(state->commit, text);

	} else if (*text == 'a' && get_line_type(text) == LINE_AUTHOR) {
		parse_author_line(text + STRING_SIZE("author "),
				  &state->author, use_author_date ? &state->author_time : NULL);

	} else if (*text == 'c' && get_line_type(text) == LINE_COMMITTER) {
		parse_author_line(text + STRING_SIZE("committer "),
				  NULL, use_author_date ? NULL : &state->author_time);

	} else if (*text == ':') {
		char *pos;
		size_t annotated = 1;
		size_t i;

		pos = strrchr(text, '\t');
		if (!pos)
			return true;
		text = pos + 1;
		if (*view->env->directory && !strncmp(text, view->env->directory, strlen(view->env->directory)))
			text += strlen(view->env->directory);
		pos = strchr(text, '/');
		if (pos)
			*pos = 0;

		for (i = 1; i < view->lines; i++) {
			struct line *line = &view->line[i];
			struct tree_entry *entry = line->data;

			annotated += !!entry->author;
			if (entry->author || strcmp(entry->name, text))
				continue;

			string_copy_rev(entry->commit, state->commit);
			entry->author = state->author;
			entry->time = state->author_time;
			line->dirty = 1;
			view_column_info_update(view, line);
			break;
		}

		if (annotated == view->lines)
			io_kill(view->pipe);
	}
	return true;
}

static bool
tree_read(struct view *view, struct buffer *buf, bool force_stop)
{
	struct tree_state *state = view->private;
	struct tree_entry *data;
	struct line *entry, *line;
	/* Note, type computed here is only used for sorting, not for drawing. */
	enum line_type type = LINE_DEFAULT;
	char *pos;
	char *mode;
	char *id;
	char *path;
	size_t size;

	if (state->read_date || !buf)
		return tree_read_date(view, buf, state);

	if (view->lines == 0 &&
	    !tree_entry(view, LINE_HEADER, view->env->directory, NULL, NULL, 0))
		return false;

	/* 100644 */
	mode = buf->data;

	/* blob */
	pos = strchr(mode, ' ');
	if (!pos || !*pos)
		return false;
	pos++;
	if (!strncmp(pos, "blob", STRING_SIZE("blob")))
		type = LINE_FILE;
	else if (!strncmp(pos, "tree", STRING_SIZE("tree")))
		type = LINE_DIRECTORY;

	/* 95925677ca47beb0b8cce7c0e0011bcc3f61470f */
	id = strchr(pos, ' ');
	if (!id || !*id)
		return false;
	id++;

	/* 213045 */
	pos = strchr(id, ' ');
	if (!pos || !*pos)
		return false;
	pos++;
	size = parse_size(pos);

	/* tig.c */
	path = strchr(pos, '\t');
	if (!path || !*path)
		return false;
	path++;

	/* Strip the path part ... */
	if (*view->env->directory) {
		size_t pathlen = strlen(path);
		size_t striplen = strlen(view->env->directory);

		if (pathlen > striplen)
			memmove(path, path + striplen,
				pathlen - striplen + 1);

		/* Insert "link" to parent directory. */
		if (view->lines == 1 &&
		    !tree_entry(view, LINE_DIRECTORY, "..", "040000", view->ref, 0))
			return false;
	}

	entry = tree_entry(view, type, path, mode, id, size);
	if (!entry)
		return false;
	data = entry->data;
	view_column_info_update(view, entry);

	/* Skip "Directory ..." and ".." line. */
	for (line = &view->line[1 + !!*view->env->directory]; line < entry; line++) {
		if (tree_compare_entry(line, entry) <= 0)
			continue;

		memmove(line + 1, line, (entry - line) * sizeof(*entry));

		line->data = data;
		line->type = type;
		line->dirty = line->cleareol = 1;
		for (line++; line <= entry; line++) {
			line->dirty = line->cleareol = 1;
			line->lineno++;
		}
		return true;
	}

	/* Move the current line to the first tree entry. */
	if (!check_position(&view->prev_pos) && !check_position(&view->pos))
		goto_view_line(view, 0, 1);

	return true;
}

static bool
tree_draw(struct view *view, struct line *line, unsigned int lineno)
{
	struct tree_entry *entry = line->data;

	if (line->type == LINE_HEADER) {
		draw_formatted(view, line->type, "Directory path /%s", entry->name);
		return true;
	}

	return view_column_draw(view, line, lineno);
}

void
open_blob_editor(const char *id, const char *name, unsigned int lineno)
{
	const char *blob_argv[] = { "git", "cat-file", "blob", id, NULL };
	char file[SIZEOF_STR];
	int fd;

	if (!name)
		name = "unknown";

	if (!string_format(file, "%s/tigblob.XXXXXX.%s", get_temp_dir(), name)) {
		report("Temporary file name is too long");
		return;
	}

	fd = mkstemps(file, strlen(name) + 1);

	if (fd == -1)
		report("Failed to create temporary file");
	else if (!io_run_append(blob_argv, fd))
		report("Failed to save blob data to file");
	else
		open_editor(file, lineno);
	if (fd != -1)
		unlink(file);
}

static enum request
tree_request(struct view *view, enum request request, struct line *line)
{
	enum open_flags flags;
	struct tree_entry *entry = line->data;

	switch (request) {
	case REQ_VIEW_BLAME:
		if (line->type != LINE_FILE) {
			report("Blame only supported for files");
			return REQ_NONE;
		}

		string_copy(view->env->ref, view->vid);
		return request;

	case REQ_EDIT:
		if (line->type != LINE_FILE) {
			report("Edit only supported for files");
		} else if (!is_head_commit(view->vid)) {
			open_blob_editor(entry->id, entry->name, 0);
		} else {
			open_editor(view->env->file, 0);
		}
		return REQ_NONE;

	case REQ_PARENT:
	case REQ_BACK:
		if (!*view->env->directory) {
			/* quit view if at top of tree */
			return REQ_VIEW_CLOSE;
		}
		/* fake 'cd  ..' */
		pop_tree_stack_entry(&view->pos);
		reload_view(view);
		return REQ_NONE;

	case REQ_ENTER:
		break;

	default:
		return request;
	}

	/* Cleanup the stack if the tree view is at a different tree. */
	if (!*view->env->directory)
		reset_view_history(&tree_view_history);

	switch (line->type) {
	case LINE_DIRECTORY:
		/* Depending on whether it is a subdirectory or parent link
		 * mangle the path buffer. */
		if (tree_path_is_parent(entry->name) && *view->env->directory) {
			pop_tree_stack_entry(&view->pos);

		} else {
			const char *basename = tree_path(line);

			push_tree_stack_entry(view, basename, &view->pos);
		}

		/* Trees and subtrees share the same ID, so they are not not
		 * unique like blobs. */
		reload_view(view);
		break;

	case LINE_FILE:
		flags = view_is_displayed(view) ? OPEN_SPLIT : OPEN_DEFAULT;
		open_blob_view(view, flags);
		break;

	default:
		return REQ_NONE;
	}

	return REQ_NONE;
}

static void
tree_select(struct view *view, struct line *line)
{
	struct tree_entry *entry = line->data;

	if (line->type == LINE_HEADER) {
		string_format(view->ref, "Files in /%s", view->env->directory);
		return;
	}

	if (line->type == LINE_DIRECTORY && tree_path_is_parent(entry->name)) {
		string_copy(view->ref, "Open parent directory");
		view->env->blob[0] = 0;
		return;
	}

	if (line->type == LINE_FILE) {
		string_copy_rev(view->env->blob, entry->id);
		string_format(view->env->file, "%s%s", view->env->directory, tree_path(line));
	}

	string_copy_rev(view->ref, entry->id);
}

static enum status_code
tree_open(struct view *view, enum open_flags flags)
{
	static const char *tree_argv[] = {
		"git", "ls-tree", "-l", "%(commit)", "--", "%(directory)", NULL
	};

	if (string_rev_is_null(view->env->commit))
		return error("No tree exists for this commit");

	if (view->lines == 0 && repo.prefix[0]) {
		char *pos = repo.prefix;

		while (pos && *pos) {
			char *end = strchr(pos, '/');

			if (end)
				*end = 0;
			push_tree_stack_entry(view, pos, &view->pos);
			pos = end;
			if (end) {
				*end = '/';
				pos++;
			}
		}

	} else if (strcmp(view->vid, view->ops->id)) {
		view->env->directory[0] = 0;
	}

	return begin_update(view, repo.exec_dir, tree_argv, flags);
}

static struct view_ops tree_ops = {
	"file",
	argv_env.commit,
	VIEW_SEND_CHILD_ENTER | VIEW_SORTABLE | VIEW_BLAME_LIKE | VIEW_REFRESH,
	sizeof(struct tree_state),
	tree_open,
	tree_read,
	tree_draw,
	tree_request,
	view_column_grep,
	tree_select,
	NULL,
	view_column_bit(AUTHOR) | view_column_bit(DATE) |
		view_column_bit(FILE_NAME) | view_column_bit(FILE_SIZE) |
		view_column_bit(ID) | view_column_bit(LINE_NUMBER) |
		view_column_bit(MODE),
	tree_get_column_data,
};

DEFINE_VIEW(tree);

/* vim: set ts=8 sw=8 noexpandtab: */
