#include <assert.h>
#include <blue/core/stringstream.h>
#include <blue/term/print.h>
#include <blue/term/tty.h>
#include <ctype.h>
#include <mie/diag/amendment.h>
#include <mie/diag/class.h>
#include <mie/diag/component.h>
#include <mie/diag/diag.h>
#include <mie/diag/highlight.h>
#include <mie/parse/line-source.h>
#include <stdlib.h>

#define GET_CHAR_STOP     0
#define GET_CHAR_CONTINUE -1

struct snippet_print_ctx {
	b_tty *ctx_stream;
	struct mie_line_source *ctx_line_source;

	size_t ctx_row, ctx_col;

	bool ctx_has_underline;
	b_stringstream *ctx_underline;
	const b_string *ctx_linebuf;
	const b_iterator *ctx_linebuf_ptr;

	struct mie_diag_c_snippet *ctx_snippet;

	const struct mie_diag_highlight *ctx_hl;
	const struct mie_diag_amendment *ctx_amendment;
};

#define __STREAM_COLOUR_ERROR   "[red,bold]"
#define __STREAM_COLOUR_WARN    "[yellow,bold]"
#define __STREAM_COLOUR_HINT    "[blue,bold]"
#define __STREAM_COLOUR_LINE_NO "[cyan]"
#define __STREAM_COLOUR_ACCENT  "[cyan]"
#define __STREAM_COLOUR_RESET   "[reset]"

#define STREAM_COLOUR_ERROR(stream)                                            \
	b_tty_puts(stream, 0, __STREAM_COLOUR_ERROR);
#define STREAM_COLOUR_WARN(stream) b_tty_puts(stream, 0, __STREAM_COLOUR_WARN);
#define STREAM_COLOUR_HINT(stream) b_tty_puts(stream, 0, __STREAM_COLOUR_HINT);
#define STREAM_COLOUR_ACCENT(stream)                                           \
	b_tty_puts(stream, 0, __STREAM_COLOUR_ACCENT);
#define STREAM_COLOUR_LINE_NO(stream)                                          \
	b_tty_puts(stream, 0, __STREAM_COLOUR_LINE_NO);
#define STREAM_COLOUR_RESET(stream)                                            \
	b_tty_puts(stream, 0, __STREAM_COLOUR_RESET);

#define STREAM_COLOUR_ERROR_B(stream, str)                                     \
	b_stream_write_string(str, __STREAM_COLOUR_ERROR, NULL);
#define STREAM_COLOUR_WARN_B(stream, str)                                      \
	b_stream_write_string(str, __STREAM_COLOUR_WARN, NULL);
#define STREAM_COLOUR_HINT_B(stream, str)                                      \
	b_stream_write_string(str, __STREAM_COLOUR_HINT, NULL);
#define STREAM_COLOUR_ACCENT_B(stream, str)                                    \
	b_stream_write_string(str, __STREAM_COLOUR_ACCENT, NULL);
#define STREAM_COLOUR_RESET_B(stream, str)                                     \
	b_stream_write_string(str, __STREAM_COLOUR_RESET, NULL);

static void print_header(struct mie_diag *diag, b_tty *dest)
{
	unsigned int w;
	b_tty_get_dimensions(dest, &w, NULL);

	const struct mie_diag_class *diag_class = diag->diag_class;
	assert(diag_class);

	STREAM_COLOUR_ACCENT(dest);

	size_t nr_written = 0;
	nr_written += b_tty_puts(dest, 0, "--- ");

	const char *s = diag_class->c_title;
	while (*s) {
		b_tty_putc(dest, 0, toupper(*s));
		s++;
		nr_written++;
	}

	b_tty_putc(dest, 0, ' ');
	nr_written++;

	while (nr_written < w) {
		b_tty_putc(dest, 0, '-');
		nr_written++;
	}

	STREAM_COLOUR_RESET(dest);

	b_tty_putc(dest, 0, '\n');
}

static void print_location(struct mie_diag *diag, b_tty *out)
{
	size_t x;
	const char *name = mie_line_source_get_path(diag->diag_src);

	b_tty_puts(out, 0, "  ");
	STREAM_COLOUR_ACCENT(out);
	b_tty_puts(out, 0, "> ");
	STREAM_COLOUR_RESET(out);
	b_tty_printf(
		out, 0, "%s:%lu:%lu\n", name, diag->diag_loc.c_row,
		diag->diag_loc.c_col);
}

static void print_msg(
	struct mie_diag *diag, struct mie_diag_c_msg *msg, b_tty *stream)
{
	b_paragraph_format format = {
		.p_left_margin = 2,
		.p_right_margin = 2,
	};

	b_print_paragraph(msg->msg_content, stream, &format);
}

static bool highlight_contains_cell(
	const struct mie_diag_highlight *hl, size_t row, size_t col)
{
	if (row < hl->hl_span.s_start.c_row || row > hl->hl_span.s_end.c_row) {
		return false;
	}

	if (row == hl->hl_span.s_start.c_row && col < hl->hl_span.s_start.c_col) {
		return false;
	}

	if (row == hl->hl_span.s_end.c_row && col > hl->hl_span.s_end.c_col) {
		return false;
	}

	return true;
}

static bool amendment_contains_cell(
	const struct mie_diag_amendment *a, size_t row, size_t col)
{
	unsigned long limit = 0;

	switch (a->a_type) {
	case MIE_DIAG_AMENDMENT_ADD:
		if (a->a_add.a_loc.c_row != row) {
			return false;
		}

		if (col < a->a_add.a_loc.c_col) {
			return false;
		}

		if (col > a->a_add.a_loc.c_col + a->__x - 1) {
			return false;
		}

		return true;
	case MIE_DIAG_AMENDMENT_REMOVE:
		if (a->a_remove.a_loc.c_row != row) {
			return false;
		}

		if (col < a->a_remove.a_loc.c_row) {
			return false;
		}

		if (col > a->a_remove.a_length) {
			return false;
		}

		return true;
	case MIE_DIAG_AMENDMENT_REPLACE:
		if (a->a_replace.a_loc.c_row != row) {
			return false;
		}

		if (col < a->a_replace.a_loc.c_row) {
			return false;
		}

		limit = a->a_replace.a_loc.c_row
		      + b_max(ulong, a->a_replace.a_length, a->__x) - 1;

		if (col > limit) {
			return false;
		}

		return true;
	default:
		return false;
	}
}

static struct mie_diag_highlight *find_highlight(
	struct mie_diag_c_snippet *snippet, size_t row, size_t col)
{
	for (size_t i = 0; i < snippet->s_nr_highlights; i++) {
		struct mie_diag_highlight *hl = &snippet->s_highlights[i];

		if (highlight_contains_cell(hl, row, col)) {
			return hl;
		}
	}

	return NULL;
}

static struct mie_diag_amendment *find_amendment(
	struct mie_diag_c_snippet *snippet, size_t row, size_t col)
{
	for (size_t i = 0; i < snippet->s_nr_amendments; i++) {
		struct mie_diag_amendment *a = &snippet->s_amendments[i];

		if (amendment_contains_cell(a, row, col)) {
			return a;
		}
	}

	return NULL;
}

static void update_amendment(struct snippet_print_ctx *ctx)
{
	if (ctx->ctx_amendment
	    && amendment_contains_cell(
		    ctx->ctx_amendment, ctx->ctx_row, ctx->ctx_col)) {
		return;
	}

	ctx->ctx_amendment
		= find_amendment(ctx->ctx_snippet, ctx->ctx_row, ctx->ctx_col);
}

static void update_highlighting(struct snippet_print_ctx *ctx)
{
	if (ctx->ctx_hl
	    && highlight_contains_cell(ctx->ctx_hl, ctx->ctx_row, ctx->ctx_col)) {
		return;
	}

	ctx->ctx_hl = NULL;

	STREAM_COLOUR_RESET(ctx->ctx_stream);

	const struct mie_diag_highlight *new_hl
		= find_highlight(ctx->ctx_snippet, ctx->ctx_row, ctx->ctx_col);

	if (!new_hl) {
		return;
	}

	ctx->ctx_has_underline = true;
	ctx->ctx_hl = new_hl;

	switch (ctx->ctx_hl->hl_type) {
	case MIE_DIAG_HIGHLIGHT_ERROR:
		STREAM_COLOUR_ERROR(ctx->ctx_stream);
		STREAM_COLOUR_ERROR_B(ctx->ctx_stream, ctx->ctx_underline);
		break;
	case MIE_DIAG_HIGHLIGHT_WARNING:
		STREAM_COLOUR_WARN(ctx->ctx_stream);
		STREAM_COLOUR_WARN_B(ctx->ctx_stream, ctx->ctx_underline);
		break;
	case MIE_DIAG_HIGHLIGHT_HINT:
		STREAM_COLOUR_HINT(ctx->ctx_stream);
		STREAM_COLOUR_HINT_B(ctx->ctx_stream, ctx->ctx_underline);
		break;
	default:
		break;
	}
}

static enum mie_status read_row(struct snippet_print_ctx *ctx, size_t row)
{
	if (ctx->ctx_linebuf_ptr) {
		b_iterator_unref(ctx->ctx_linebuf_ptr);
		ctx->ctx_linebuf_ptr = NULL;
	}

	ctx->ctx_has_underline = false;

	size_t nr_read;
	enum mie_status status = mie_line_source_get_row(
		ctx->ctx_line_source, row, &ctx->ctx_linebuf);
	if (status != MIE_SUCCESS) {
		return status;
	}

	ctx->ctx_linebuf_ptr = b_iterator_cbegin(ctx->ctx_linebuf);
	return MIE_SUCCESS;
}

static int get_char_amendment(struct snippet_print_ctx *ctx)
{
	const struct mie_diag_amendment *a = ctx->ctx_amendment;
	size_t i = 0;
	int c = 0;

	switch (a->a_type) {
	case MIE_DIAG_AMENDMENT_ADD:
		i = ctx->ctx_col - a->a_add.a_loc.c_row;
		return a->a_add.a_str[i];
	case MIE_DIAG_AMENDMENT_REMOVE:
		b_iterator_move_next(ctx->ctx_linebuf_ptr);
		return GET_CHAR_CONTINUE;
	case MIE_DIAG_AMENDMENT_REPLACE:
		i = ctx->ctx_col - a->a_add.a_loc.c_col;

		if (i > a->__x) {
			i = a->__x;
		}

		c = a->a_replace.a_str[i];
		if (i < a->a_replace.a_length) {
			b_iterator_move_next(ctx->ctx_linebuf_ptr);
		}

		if (c != 0) {
			return c;
		}

		return GET_CHAR_CONTINUE;
	default:
		break;
	}

	return GET_CHAR_CONTINUE;
}

static int get_char(struct snippet_print_ctx *ctx)
{
	if (ctx->ctx_amendment) {
		return get_char_amendment(ctx);
	}

	b_wchar c = b_iterator_get_cvalue(ctx->ctx_linebuf_ptr).v_int;
	if (c == B_WCHAR_INVALID) {
		return GET_CHAR_STOP;
	};

	b_iterator_move_next(ctx->ctx_linebuf_ptr);
	return c;
}

static void update_underline(struct snippet_print_ctx *ctx)
{
	if (!ctx->ctx_hl) {
		b_stream_write_char(ctx->ctx_underline, ' ');
		return;
	}

	switch (ctx->ctx_hl->hl_type) {
	case MIE_DIAG_HIGHLIGHT_ERROR:
	case MIE_DIAG_HIGHLIGHT_WARNING:
	case MIE_DIAG_HIGHLIGHT_HINT:
		b_stream_write_char(ctx->ctx_underline, '^');
		break;
	default:
		b_stream_write_char(ctx->ctx_underline, ' ');
		break;
	}
}

static void write_underline(struct snippet_print_ctx *ctx)
{
	if (!ctx->ctx_has_underline) {
		return;
	}

	STREAM_COLOUR_RESET(ctx->ctx_stream);
	STREAM_COLOUR_LINE_NO(ctx->ctx_stream);
	b_tty_puts(ctx->ctx_stream, 0, "       : ");
	b_tty_puts(ctx->ctx_stream, 0, b_stringstream_ptr(ctx->ctx_underline));
	STREAM_COLOUR_RESET(ctx->ctx_stream);
	b_tty_putc(ctx->ctx_stream, 0, '\n');
}

static void print_snippet(
	struct mie_diag *diag, struct mie_diag_c_snippet *snippet, b_tty *stream)
{
	enum mie_status status = MIE_SUCCESS;

	struct snippet_print_ctx printer = {
		.ctx_stream = stream,
		.ctx_snippet = snippet,
		.ctx_underline = b_stringstream_create(),
		.ctx_line_source = diag->diag_src,
	};

	for (unsigned long row = snippet->s_first_line;
	     row <= snippet->s_last_line; row++) {
		STREAM_COLOUR_LINE_NO(stream);
		b_tty_printf(stream, 0, "  %4lu | ", row);
		printer.ctx_row = row;

		status = read_row(&printer, row);
		if (status != MIE_SUCCESS) {
			break;
		}

		for (size_t i = 0;; i++) {
			printer.ctx_col = i + 1;

			update_amendment(&printer);

			int c = get_char(&printer);

			if (c == GET_CHAR_CONTINUE) {
				continue;
			} else if (c == GET_CHAR_STOP || c == '\n') {
				break;
			}

			update_highlighting(&printer);

			b_tty_putc(stream, 0, c);

			update_underline(&printer);
		}

		b_tty_putc(stream, 0, '\n');
		write_underline(&printer);
	}

	b_stringstream_unref(printer.ctx_underline);
}

static void print_component(
	struct mie_diag *diag, struct mie_diag_component *component, b_tty *stream)
{
	switch (component->c_type) {
	case MIE_DIAG_COMPONENT_MSG:
		print_msg(diag, (struct mie_diag_c_msg *)component, stream);
		break;
	case MIE_DIAG_COMPONENT_SNIPPET:
		print_snippet(diag, (struct mie_diag_c_snippet *)component, stream);
		break;
	default:
		abort();
	}
}

enum mie_status mie_diag_write_pretty(struct mie_diag *diag, b_tty *stream)
{
	print_header(diag, stream);
	print_location(diag, stream);

	b_queue_entry *entry = b_queue_first(&diag->diag_components);
	while (entry) {
		struct mie_diag_component *c
			= b_unbox(struct mie_diag_component, entry, c_entry);

		b_tty_putc(stream, 0, '\n');
		print_component(diag, c, stream);

		entry = b_queue_next(entry);
	}

	return MIE_SUCCESS;
}