package findr

import "core:fmt"
import "core:os"
import "core:strings"
import "core:sys/linux"

RawEntry :: struct {
	name: string,
	type: linux.Dirent_Type,
}

walk :: proc(root: string, results: ^[dynamic]string) {
	walk_dir(root, results)
}

walk_dir :: proc(dir_path: string, results: ^[dynamic]string) {
	cpath := strings.clone_to_cstring(dir_path)
	if cpath == nil do return
	defer delete(cpath)

	fd, err := linux.open(cpath, {.DIRECTORY, .CLOEXEC})
	if err != .NONE do return
	defer linux.close(fd)

	buf: [8192]u8
	has_git := false

	entries := make([dynamic]RawEntry)
	defer {
		for &entry in entries {
			delete(entry.name)
		}
		delete(entries)
	}

	for {
		n, errno := linux.getdents(fd, buf[:])
		if n <= 0 || errno != .NONE do break

		offs := 0
		for d in linux.dirent_iterate_buf(buf[:n], &offs) {
			name := linux.dirent_name(d)
			if name == "." || name == ".." do continue

			if name == ".git" && d.type == .DIR {
				has_git = true
			}

			cloned := strings.clone(name)
			append(&entries, RawEntry{name = cloned, type = d.type})
		}
	}

	if has_git {
		gi := load_gitignore(dir_path)
		defer if gi != nil {
			destroy(gi)
			free(gi)
		}

		for entry in entries {
			if entry.name == ".git" do continue
			is_dir := entry.type == .DIR
			if gi != nil && is_ignored(gi, entry.name, is_dir) {
				if !is_dir {
					full_path := join_path(dir_path, entry.name)
					append(results, full_path)
				}
				continue
			}
			if is_dir {
				child_path := join_path(dir_path, entry.name)
				walk_dir(child_path, results)
				delete(child_path)
			}
		}
	} else {
		for entry in entries {
			if entry.type == .DIR {
				child_path := join_path(dir_path, entry.name)
				walk_dir(child_path, results)
				delete(child_path)
			}
		}
	}
}

load_gitignore :: proc(dir_path: string) -> ^Gitignore {
	gi_path := join_path(dir_path, ".gitignore")
	defer delete(gi_path)

	data, err := os.read_entire_file_from_path(gi_path, context.allocator)
	if err != nil do return nil

	gi := new(Gitignore)
	gi^ = parse(string(data))
	delete(data)
	return gi
}

join_path :: proc(parent, child: string) -> string {
	b: strings.Builder
	strings.builder_init(&b)
	defer strings.builder_destroy(&b)

	fmt.sbprintf(&b, "%s", parent)
	if len(parent) == 0 || parent[len(parent) - 1] != '/' {
		fmt.sbprintf(&b, "/")
	}
	fmt.sbprintf(&b, "%s", child)

	s := strings.to_string(b)
	result, _ := strings.clone(s)
	return result
}