#include "../ctx.h"
#include "../diag.h"
#include "../stream.h"
#include "../write.h"

#include <assert.h>
#include <blue/core/stringstream.h>
#include <blue/term/tty.h>
#include <ctype.h>
#include <ivy/line-source.h>
#include <stdlib.h>

#define GET_CHAR_STOP     0
#define GET_CHAR_CONTINUE -1

struct snippet_print_ctx {
	struct ivy_diag_stream *ctx_stream;
	struct ivy_line_source *ctx_line_source;

	size_t ctx_row, ctx_col;

	char ctx_underline_buf[256];
	char ctx_line_buf[256];
	size_t ctx_line_buf_ptr;

	bool ctx_has_underline;
	b_stringstream ctx_underline;

	struct diag_c_snippet *ctx_snippet;

	const struct ivy_diag_highlight *ctx_hl;
	const struct ivy_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_ACCENT "[cyan]"
#define __STREAM_COLOUR_RESET  "[reset]"

#define STREAM_COLOUR_ERROR(stream)                                            \
	if (DIAG_STREAM_FLAG_SET(stream, IVY_DIAG_STREAM_F_COLOUR)) {          \
		diag_stream_puts(stream, __STREAM_COLOUR_ERROR);               \
	}
#define STREAM_COLOUR_WARN(stream)                                             \
	if (DIAG_STREAM_FLAG_SET(stream, IVY_DIAG_STREAM_F_COLOUR)) {          \
		diag_stream_puts(stream, __STREAM_COLOUR_WARN);                \
	}
#define STREAM_COLOUR_HINT(stream)                                             \
	if (DIAG_STREAM_FLAG_SET(stream, IVY_DIAG_STREAM_F_COLOUR)) {          \
		diag_stream_puts(stream, __STREAM_COLOUR_HINT);                \
	}
#define STREAM_COLOUR_ACCENT(stream)                                           \
	if (DIAG_STREAM_FLAG_SET(stream, IVY_DIAG_STREAM_F_COLOUR)) {          \
		diag_stream_puts(stream, __STREAM_COLOUR_ACCENT);              \
	}
#define STREAM_COLOUR_RESET(stream)                                            \
	if (DIAG_STREAM_FLAG_SET(stream, IVY_DIAG_STREAM_F_COLOUR)) {          \
		diag_stream_puts(stream, __STREAM_COLOUR_RESET);               \
	}

#define STREAM_COLOUR_ERROR_B(stream, str)                                     \
	if (DIAG_STREAM_FLAG_SET(stream, IVY_DIAG_STREAM_F_COLOUR)) {          \
		b_stringstream_add(str, __STREAM_COLOUR_ERROR);                \
	}
#define STREAM_COLOUR_WARN_B(stream, str)                                      \
	if (DIAG_STREAM_FLAG_SET(stream, IVY_DIAG_STREAM_F_COLOUR)) {          \
		b_stringstream_add(str, __STREAM_COLOUR_WARN);                 \
	}
#define STREAM_COLOUR_HINT_B(stream, str)                                      \
	if (DIAG_STREAM_FLAG_SET(stream, IVY_DIAG_STREAM_F_COLOUR)) {          \
		b_stringstream_add(str, __STREAM_COLOUR_HINT);                 \
	}
#define STREAM_COLOUR_ACCENT_B(stream, str)                                    \
	if (DIAG_STREAM_FLAG_SET(stream, IVY_DIAG_STREAM_F_COLOUR)) {          \
		b_stringstream_add(str, __STREAM_COLOUR_ACCENT);               \
	}
#define STREAM_COLOUR_RESET_B(stream, str)                                     \
	if (DIAG_STREAM_FLAG_SET(stream, IVY_DIAG_STREAM_F_COLOUR)) {          \
		b_stringstream_add(str, __STREAM_COLOUR_RESET);                \
	}

static void print_header(
	struct ivy_diag_ctx *ctx, struct ivy_diag *diag,
	struct ivy_diag_stream *stream)
{
	size_t w;
	diag_stream_get_dimensions(stream, NULL, &w);

	const struct ivy_diag_class *diag_class
		= diag_ctx_get_class(ctx, diag->diag_class);
	assert(diag_class);

	STREAM_COLOUR_ACCENT(stream);

	diag_stream_puts(stream, "--- ");

	const char *s = diag_class->c_title;
	while (*s) {
		diag_stream_putc(stream, toupper(*s));
		s++;
	}

	diag_stream_putc(stream, ' ');

	while (DIAG_STREAM_COL(stream) <= w) {
		diag_stream_putc(stream, '-');
	}

	STREAM_COLOUR_RESET(stream);

	diag_stream_putc(stream, '\n');
}

static void print_location(
	struct ivy_diag_ctx *ctx, struct ivy_diag *diag,
	struct ivy_diag_stream *stream)
{
	char name[512];
	size_t x;
	enum ivy_status status = ivy_line_source_get_name(
		ctx->ctx_line_source, name, sizeof name, &x);
	if (status != IVY_OK) {
		return;
	}

	diag_stream_puts(stream, "  ");
	STREAM_COLOUR_ACCENT(stream);
	diag_stream_puts(stream, "> ");
	STREAM_COLOUR_RESET(stream);
	diag_stream_printf(
		stream, "%s:%lu:%lu\n", name, diag->diag_row, diag->diag_col);
}

static void print_msg(
	struct ivy_diag_ctx *ctx, struct ivy_diag *diag, struct diag_c_msg *msg,
	struct ivy_diag_stream *stream)
{
	diag_stream_puts(stream, "  ");
	diag_stream_puts(stream, msg->msg_content);
	diag_stream_putc(stream, '\n');
}

static bool highlight_contains_cell(
	const struct ivy_diag_highlight *hl, size_t row, size_t col)
{
	if (row < hl->h_start_row || row > hl->h_end_row) {
		return false;
	}

	if (row == hl->h_start_row && col < hl->h_start_col) {
		return false;
	}

	if (row == hl->h_end_row && col > hl->h_end_col) {
		return false;
	}

	return true;
}

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

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

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

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

		return true;
	case IVY_DIAG_AMENDMENT_REMOVE:
		if (a->a_remove.a_row != row) {
			return false;
		}

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

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

		return true;
	case IVY_DIAG_AMENDMENT_REPLACE:
		if (a->a_replace.a_row != row) {
			return false;
		}

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

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

		if (col > limit) {
			return false;
		}

		return true;
	default:
		return false;
	}
}

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

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

	return NULL;
}

static struct ivy_diag_amendment *find_amendment(
	struct diag_c_snippet *snippet, size_t row, size_t col)
{
	b_queue_iterator it;
	for (size_t i = 0; i < snippet->s_nr_amendments; i++) {
		struct ivy_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 ivy_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->h_type) {
	case IVY_DIAG_HIGHLIGHT_ERROR:
		STREAM_COLOUR_ERROR(ctx->ctx_stream);
		STREAM_COLOUR_ERROR_B(ctx->ctx_stream, &ctx->ctx_underline);
		break;
	case IVY_DIAG_HIGHLIGHT_WARNING:
		STREAM_COLOUR_WARN(ctx->ctx_stream);
		STREAM_COLOUR_WARN_B(ctx->ctx_stream, &ctx->ctx_underline);
		break;
	case IVY_DIAG_HIGHLIGHT_HINT:
		STREAM_COLOUR_HINT(ctx->ctx_stream);
		STREAM_COLOUR_HINT_B(ctx->ctx_stream, &ctx->ctx_underline);
		break;
	default:
		break;
	}
}

static enum ivy_status read_row(struct snippet_print_ctx *ctx, size_t row)
{
	ctx->ctx_line_buf[0] = 0;
	ctx->ctx_underline_buf[0] = 0;
	ctx->ctx_line_buf_ptr = 0;
	ctx->ctx_has_underline = false;

	b_stringstream_begin(
		&ctx->ctx_underline, ctx->ctx_underline_buf,
		sizeof ctx->ctx_underline_buf);

	size_t nr_read;
	return ivy_line_source_get_row(
		ctx->ctx_line_source, row, ctx->ctx_line_buf,
		sizeof ctx->ctx_line_buf, &nr_read);
}

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

	switch (a->a_type) {
	case IVY_DIAG_AMENDMENT_ADD:
		i = ctx->ctx_col - a->a_add.a_col;
		return a->a_add.a_str[i];
	case IVY_DIAG_AMENDMENT_REMOVE:
		ctx->ctx_line_buf_ptr++;
		return GET_CHAR_CONTINUE;
	case IVY_DIAG_AMENDMENT_REPLACE:
		i = ctx->ctx_col - a->a_add.a_col;

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

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

	int c = ctx->ctx_line_buf[ctx->ctx_line_buf_ptr];
	if (c == 0) {
		return GET_CHAR_STOP;
	};

	ctx->ctx_line_buf_ptr++;
	return c;
}

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

	switch (ctx->ctx_hl->h_type) {
	case IVY_DIAG_HIGHLIGHT_ERROR:
	case IVY_DIAG_HIGHLIGHT_WARNING:
		b_stringstream_add(&ctx->ctx_underline, "^");
		break;
	case IVY_DIAG_HIGHLIGHT_HINT:
		b_stringstream_add(&ctx->ctx_underline, "-");
		break;
	default:
		b_stringstream_add(&ctx->ctx_underline, " ");
		break;
	}
}

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

	STREAM_COLOUR_ACCENT(ctx->ctx_stream);
	diag_stream_puts(ctx->ctx_stream, "       | ");
	diag_stream_puts(ctx->ctx_stream, ctx->ctx_underline_buf);
	STREAM_COLOUR_RESET(ctx->ctx_stream);
	diag_stream_putc(ctx->ctx_stream, '\n');
}

static void print_snippet(
	struct ivy_diag_ctx *ctx, struct ivy_diag *diag,
	struct diag_c_snippet *snippet, struct ivy_diag_stream *stream)
{
	enum ivy_status status = IVY_OK;

	struct snippet_print_ctx printer = {
		.ctx_stream = stream,
		.ctx_snippet = snippet,
		.ctx_line_source = ctx->ctx_line_source,
	};

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

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

			update_highlighting(&printer);

			diag_stream_putc(stream, c);

			update_underline(&printer);
		}

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

static void print_component(
	struct ivy_diag_ctx *ctx, struct ivy_diag *diag,
	struct diag_component *component, struct ivy_diag_stream *stream)
{
	switch (component->c_type) {
	case DIAG_COMPONENT_MSG:
		print_msg(ctx, diag, (struct diag_c_msg *)component, stream);
		break;
	case DIAG_COMPONENT_SNIPPET:
		print_snippet(ctx, diag, (struct diag_c_snippet *)component, stream);
		break;
	default:
		abort();
	}
}

static enum ivy_status write(
	struct ivy_diag_ctx *ctx, struct ivy_diag *diag,
	struct ivy_diag_stream *stream)
{
	print_header(ctx, diag, stream);
	print_location(ctx, diag, stream);

	b_queue_iterator it;
	b_queue_foreach (&it, &diag->diag_components) {
		struct diag_component *c
			= b_unbox(struct diag_component, it.entry, c_entry);

		diag_stream_putc(stream, '\n');
		print_component(ctx, diag, c, stream);
	}

	return IVY_OK;
}

struct diag_writer pretty_writer = {
	.write = write,
};