package codegen

import "core:fmt"
import "core:os"
import "core:strings"
import "core:unicode/utf8"

string_iterate_words :: proc(content: ^string) -> (word: string, new_paragraph: bool, cond: bool) {
	num_newlines := 0
	word_start := -1
	word_end := len(content)
	for r, i in content {
		if strings.is_space(r) {
			if word_start >= 0 {
				word_end = i
				break
			}
			if r == '\n' {
				num_newlines += 1
			}
			continue
		}
		if word_start < 0 {
			word_start = i
		}
	}

	if word_start == -1 {
		return "", false, false
	}

	word = content[word_start:word_end]
	content^ = content[word_end:]
	return word, num_newlines > 1, true
}

gen_normalized_text :: proc(file: ^os.File, content: string, prefix := "") {
	content := content
	width := WIDTH - utf8.rune_count(prefix)

	column_rune_i := 0
	for word, new_paragraph in string_iterate_words(&content) {
		word_rune_width := utf8.rune_count(word)
		if new_paragraph {
			fmt.fprint(file, "\n\n")
			column_rune_i = 0
		} else if column_rune_i > 0 && column_rune_i + word_rune_width > width {
			fmt.fprint(file, "\n")
			column_rune_i = 0
		}
		if column_rune_i == 0 && prefix != "" {
			fmt.fprint(file, prefix)
		}
		fmt.fprintf(file, "{} ", word)
		column_rune_i += word_rune_width + 1
	}
	fmt.fprint(file, "\n")
}

gen_description :: proc(file: ^os.File, description: Description) {
	if description.summary == "" && description.body == "" {
		return
	}

	fmt.fprintln(file, BLOCK_COMMENT_BEGIN)
	if description.summary != "" {
		gen_normalized_text(file, description.summary)
		fmt.fprintln(file)
	}
	if description.body != "" {
		gen_normalized_text(file, description.body)
	}
	fmt.fprintln(file, BLOCK_COMMENT_END)
}

gen_header :: proc(file: ^os.File, protocol: Protocol) {
    fmt.fprintln(
	    file,
	    BLOCK_COMMENT_BEGIN,
	    BIG_BLOCK_SEPARATOR,
	    CODEGEN_HEADER,
	    BIG_BLOCK_SEPARATOR,
	    "",
		protocol.file_name,
		"",
		sep="\n"
	)
	gen_normalized_text(file, protocol.copyright)
	fmt.fprintln(file, "", BIG_BLOCK_SEPARATOR, sep="\n")

    if protocol.description.summary != "" || protocol.description.body != "" {
	    fmt.fprint(file, "\n")
	    if protocol.description.summary != "" {
		    gen_normalized_text(file, protocol.description.body)
	    }
	    if protocol.description.body != "" {
		    gen_normalized_text(file, protocol.description.body)
	    }
	    fmt.fprint(file, "\n")
	    fmt.fprintln(file, BIG_BLOCK_SEPARATOR)
    }
    fmt.fprintln(file, BLOCK_COMMENT_END, "\n")
}

gen_imports :: proc(file: ^os.File, protocol: Protocol) {
	fmt.fprintln(
		file,
		"""
		#+build linux
		package wayland

		import "base:intrinsics"
		import "core:fmt"
		import "core:log"
		import "core:io"

		""",
	)
}

gen_interface :: proc(file: ^os.File, protocol: Protocol, interface: Interface) {
	fmt.fprintln(file, BIG_SEPARATOR)
	fmt.fprintln(file, "// ", strings.to_upper_snake_case(interface.name), "\n", sep="")

	gen_description(file, interface.description)

	interface_name := strings.to_ada_case(interface.name)
	fmt.fprintln(file, interface_name, "_ID :: distinct Object_ID", sep="")
	screaming_interface_name := strings.to_upper_snake_case(interface.name)
	fmt.fprintln(file, screaming_interface_name, "_INTERFACE_NAME :: \"", interface.name, "\"", sep="")
	fmt.fprintln(file, screaming_interface_name, "_INTERFACE_VERSION :: ", interface.version, sep="")
	fmt.fprintln(file)

	if len(interface.requests) > 0 {
		fmt.fprintln(file, SMALL_SEPARATOR, "// REQUESTS", "", sep="\n")
		fmt.fprintln(file, interface_name, "_Request :: enum Opcode {", sep="")
		for request, i in interface.requests {
			fmt.fprint(file, "\t", strings.to_ada_case(request.name), " = ", i, ",", sep="")
			if request.description.summary != "" {
				 fmt.fprint(file, " //", request.description.summary)
			}
			fmt.fprintln(file)
		}
		fmt.fprintln(file, "}", "", sep="\n")
		for request in interface.requests {
			gen_request(file, protocol, interface, request)
		}
	}

	if len(interface.events) > 0 {
		fmt.fprintln(file, SMALL_SEPARATOR, "// EVENTS", "", sep="\n")
	}

	fmt.fprintln(file)
}

gen_request :: proc(file: ^os.File, protocol: Protocol, interface: Interface, request: Message) {
	if request.description.summary != "" || request.description.body != "" {
		fmt.fprintln(file, BLOCK_COMMENT_BEGIN)
		if request.description.summary != "" {
			gen_normalized_text(file, request.description.summary)
			fmt.fprint(file, "\n")
		}
		if request.description.body != "" {
			gen_normalized_text(file, request.description.body)
		}
		fmt.fprintln(file, BLOCK_COMMENT_END)
	}

	fmt.fprintln(file, REQUIRE_RESULTS_ATTRIBUTE)
	fmt.fprintln(
		file,
		strings.to_snake_case(interface.name),
		"_",
		strings.to_snake_case(request.name),
		" :: proc(session: ^Session) {}",
		sep=""
	)

	fmt.fprintln(file)
}