const es = @import("root");
const std = @import("std");

const Allocator = std.mem.Allocator;
const ArrayList = std.ArrayList;
const Buffer = es.Buffer;
const Config = es.Config;
const Highlight = es.Highlight;
const Row = @This();
const StringBuilder = es.StringBuilder;

allocator: Allocator,

idx: usize,

data: ArrayList(u8),
rdata: ArrayList(u8),
hldata: ArrayList(Highlight),

ends_with_open_comment: bool,

pub fn init(allocator: Allocator, idx: usize, data: []const u8) !Row {
    var self = Row{
        .allocator = allocator,

        .idx = idx,

        .data = ArrayList(u8).init(allocator),
        .rdata = ArrayList(u8).init(allocator),
        .hldata = ArrayList(Highlight).init(allocator),

        .ends_with_open_comment = false,
    };
    errdefer self.deinit();

    try self.data.appendSlice(data);
    return self;
}

pub fn deinit(self: Row) void {
    self.data.deinit();
    self.rdata.deinit();
    self.hldata.deinit();
}

pub fn appendString(self: *Row, buf: *Buffer, str: []const u8) !void {
    try self.data.appendSlice(str);
    return self.update(buf);
}

pub fn cleanWhiteSpace(self: *Row, buf: *Buffer) !void {
    const orig_len = self.data.items.len;
    while (self.data.items.len > 0) {
        if (std.ascii.isWhitespace(self.data.items[self.data.items.len - 1])) {
            _ = self.data.pop();
        } else {
            break;
        }
    }

    if (orig_len != self.data.items.len) {
        buf.edited = true;
        try self.update(buf);
    }
}

pub fn cxToRx(self: Row, config: Config, cx: usize) usize {
    var rx: usize = 0;
    var i: usize = 0;
    while (i < cx) : (i += 1) {
        if (self.data.items[i] == '\t') {
            rx += config.tab_stop - (rx % config.tab_stop);
        } else {
            rx += 1;
        }
    }

    return rx;
}

pub fn deleteChar(self: *Row, buf: *Buffer, at: usize) !void {
    _ = self.data.orderedRemove(at);
    try self.update(buf);
}

pub fn indentationSize(self: Row) usize {
    var idx: usize = 0;
    while (idx < self.data.items.len) : (idx += 1) {
        if (!std.ascii.isWhitespace(self.data.items[idx])) {
            break;
        }
    }

    return idx;
}

pub fn insertChar(self: *Row, buf: *Buffer, at: usize, char: u8) !void {
    try self.data.insert(at, char);
    try self.update(buf);
}

pub fn rxToCx(self: Row, config: Config, rx: usize) usize {
    if (rx == 0) {
        return 0;
    }

    var cur_rx: usize = 0;
    for (self.data.items, 0..) |char, cx| {
        if (char == '\t') {
            cur_rx += config.tab_stop - (cur_rx % config.tab_stop);
        } else {
            cur_rx += 1;
        }

        if (cur_rx >= rx) {
            return cx + 1;
        }
    }

    return self.data.items.len;
}

// TODO: I don't like that this is modifying both row and buffer (parent of row)
pub fn update(self: *Row, buf: *Buffer) !void {
    self.rdata.clearRetainingCapacity();

    for (self.data.items) |char| {
        if (char == '\t') {
            const len = buf.config.tab_stop - self.rdata.items.len % buf.config.tab_stop;
            try self.rdata.appendNTimes(' ', len);
        } else {
            try self.rdata.append(char);
        }
    }

    try self.updateSyntax(buf);
}

const UpdateSyntaxError = std.mem.Allocator.Error;
pub fn updateSyntax(self: *Row, buf: *Buffer) UpdateSyntaxError!void {
    try self.hldata.resize(self.rdata.items.len);
    @memset(self.hldata.items, .normal);
    if (buf.syntax == null) {
        return;
    }

    const syntax = buf.syntax.?;

    var in_comment = if (self.idx > 0) buf.rows.items[self.idx - 1].ends_with_open_comment else false;
    var curr_str_quote: ?u8 = null;

    var i: usize = 0;
    var last_sep: usize = 0;
    main_loop: while (i < self.rdata.items.len) {
        const prev_hl = if (i > 0) self.hldata.items[i - 1] else .normal;

        if (syntax.singleline_comment_start) |scs| {
            std.debug.assert(scs.len != 0);
            if (curr_str_quote == null and !in_comment and scs.len + i <= self.rdata.items.len) {
                if (std.mem.eql(u8, scs, self.rdata.items[i..(i + scs.len)])) {
                    @memset(self.hldata.items[i..], .comment);
                    break :main_loop;
                }
            }
        }

        if (syntax.multiline_comment_start) |mcs| {
            std.debug.assert(mcs.len != 0);
            if (syntax.multiline_comment_end) |mce| {
                std.debug.assert(mce.len != 0);
                if (curr_str_quote == null) {
                    if (in_comment) {
                        self.hldata.items[i] = .comment_ml;
                        if (mce.len + i <= self.rdata.items.len and std.mem.eql(u8, mce, self.rdata.items[i..(i + mce.len)])) {
                            @memset(self.hldata.items[i..(i + mce.len)], .comment_ml);
                            i += mce.len;
                            in_comment = false;
                            last_sep = i;
                        } else {
                            i += 1;
                            continue :main_loop;
                        }
                    } else if (mcs.len + i <= self.rdata.items.len and std.mem.eql(u8, mcs, self.rdata.items[i..(i + mcs.len)])) {
                        @memset(self.hldata.items[i..(i + mcs.len)], .comment_ml);
                        i += mcs.len;
                        in_comment = true;
                        continue :main_loop;
                    }
                }
            }
        }

        const c = self.rdata.items[i];

        if (syntax.flags.hl_strings) {
            if (curr_str_quote) |quote| {
                self.hldata.items[i] = .string;
                i += 1;
                // Pretty dumb way of detecting \" or \' but it works \shrug/
                if (c == '\\' and i < self.rdata.items.len) {
                    self.hldata.items[i] = .string;
                    i += 1;
                } else if (c == quote) {
                    curr_str_quote = null;
                    last_sep = i;
                }

                continue :main_loop;
            } else {
                // TODO: Move this to syntax struct
                if (c == '"' or c == '\'') {
                    curr_str_quote = c;
                    self.hldata.items[i] = .string;
                    i += 1;
                    continue :main_loop;
                }
            }
        }

        if (syntax.flags.hl_numbers) {
            if ((std.ascii.isDigit(c) and (last_sep == i or prev_hl == .number)) or (c == '.' and prev_hl == .number)) {
                self.hldata.items[i] = .number;
                i += 1;
                continue :main_loop;
            }
        }

        if (syntax.isSeparator(c)) {
            const id = self.rdata.items[last_sep..i];
            if (syntax.keyword_classifier(id)) |hl| {
                @memset(self.hldata.items[last_sep..i], hl);
            }

            last_sep = i + 1;
        }

        i += 1;
    }

    if (!in_comment) {
        const id = self.rdata.items[last_sep..self.rdata.items.len];
        if (syntax.keyword_classifier(id)) |hl| {
            @memset(self.hldata.items[last_sep..self.rdata.items.len], hl);
        }
    }

    if (in_comment != self.ends_with_open_comment) {
        self.ends_with_open_comment = in_comment;
        if (self.idx + 1 < buf.rows.items.len) {
            try buf.rows.items[self.idx + 1].updateSyntax(buf);
        }
    }
}