#!/usr/bin/env python3
#
# This file contains a simple test program for demonstrating some basic Python
# BTUI usage.
#
import PIL
import btui.Python.btui as btui
import climage
import marko
import os
import re
import subprocess
import time
import webbrowser

from collections import namedtuple
from marko.helpers import MarkoExtension
from marko.inline import *
from pygments import highlight
from pygments.formatters import Terminal256Formatter
from pygments.lexers import get_lexer_by_name
from pygments.util import ClassNotFound
from wcwidth import wcswidth

Slide = namedtuple("Slide", ("filename", "text"))
class Demo(namedtuple("_Demo", ("element", "demo"))):
    __slots__ = ()
    def __call__(self): self.demo()

FORMATTER = Terminal256Formatter(style="native")
BULLET = "\033[1m\033(0`\033(B\033[m"

terminal_width, terminal_height = 0, 0
highlighted_element = None

def render_width(text:str)->int:
    # Strip out escape sequences that are used:
    text = text.replace(BULLET, "*")
    text = re.sub("\033\\[[\\d;]*.", "", text)
    text = re.sub("\033\\(.", "", text)
    text = re.sub("\t", "    ", text)

    width = wcswidth(text)
    assert(width >= 0) # Can happen if we missed some escape characters
    return width

def is_image(path:str)->bool:
    return any(path.lower().endswith(ext) for ext in ('.png', '.jpg', '.jpeg', '.bmp', '.gif', '.webp'))

def boxed(text:str, line_numbers=False, box_color="", min_width=0):
    text = re.sub("\t", "    ", text)
    lines = text.splitlines()
    width = 2 + max(render_width(line) for line in lines) + 2
    if line_numbers: width += len(str(len(lines))) + 1
    width = max(min_width, width)

    rendered = [box_color + "\033(0l" + "q"*(width-2) + "k\033(B" + "\033[m"]
    for i,line in enumerate(lines):
        pad = width - render_width(line) - 4
        if line_numbers:
            num_w = len(str(len(lines)))
            pad -= num_w+1
            rendered.append(f"{box_color}\033(0x\033(B\033[0;2m{box_color}{i+1:>{num_w}}\033(0x\033(B\033[m {line}{' '*pad} {box_color}\033(0x\033(B\033[m")
        else:
            rendered.append(f"{box_color}\033(0x\033(B\033[m {line}{' '*pad} {box_color}\033(0x\033(B\033[m")
    rendered.append(box_color + "\033(0m" + "q"*(width-2) + "j\033(B" + "\033[m")
    return "\n".join(rendered)

class TerminalRenderer(marko.Renderer):
    width = 40
    relative_filename = "."

    def render_document(self, element):
        return self.render_children(element)

    def render_children(self, element):
        if isinstance(element, str):
            return element  # Avoid treating it as an object
        return super().render_children(element)

    def render_heading(self, element):
        title = " "+self.render_children(element)+" "
        if element.level == 1:
            #return "\033[1;34m" + pyfiglet.figlet_format(title, width=200, font="big").rstrip('\n') + "\033[m\n\n"
            line = "\033[1;7m" + " "*TerminalRenderer.width + "\033[22;27m\n"
            return line + f"\033[1;7m{title:^{TerminalRenderer.width}}\033[22;27m\n" + line + "\n"
        else:
            return f"\033[1;7m{title:^{TerminalRenderer.width}}\033[22;27m\n\n"

    _list_depth = 0
    def render_list(self, element) -> str:
        lines = []
        if element.ordered:
            for num, child in enumerate(element.children, element.start):
                child.bullet = f"\033[1m{num:>2}.\033[m "
                child_rendered = self.render(child).strip('\n').replace('\n', '\n    ')
                lines.append(child_rendered)
        else:
            for child in element.children:
                child.bullet = "  "+BULLET+" "
                child_rendered = self.render(child).strip('\n').replace('\n', '\n    ')
                lines.append(child_rendered)
        return "\n".join(lines) + "\n\n"
    
    def render_list_item(self, element) -> str:
        indent = "  "*self._list_depth
        self._list_depth += 1
        result = indent + element.bullet + "\n".join(self.render(child).strip('\n') for child in element.children)
        self._list_depth -= 1
        return result

    def render_image(self, element) -> str:
        path = element.dest if os.path.isabs(element.dest) else os.path.join(os.path.dirname(self.relative_filename), element.dest)
        if is_image(path):
            img = PIL.Image.open(path)
            img_width, img_height = img.size
            render_width, render_height = img_width, img_height

            two_thirds_width = max(40, 2*terminal_width//3)
            if two_thirds_width < render_width:
                render_width = two_thirds_width
                render_height = int(img_height * (render_width/img_width)/2)

            two_thirds_height = max(40, 2*terminal_height//3)
            if two_thirds_height < render_height:
                render_height = two_thirds_height
                render_width = int(img_width * 2*(render_height/img_height))

            option_string = markdown.render(element.children[0]) if element.children else ""
            for w in re.findall(r'width=(\d+)%', option_string):
                render_width = int(terminal_width * float(w)/100)
                render_height = int(img_height * (render_width/img_width)/2)

            for h in re.findall(r'height=(\d+)%', option_string):
                render_height = int(terminal_height * float(h)/100)
                render_width = int(img_width * 2*(render_height/img_height))

            output = climage.convert(path, width=render_width, is_truecolor=True, is_256color=False, is_unicode=True)
            if element is highlighted_element:
                output = output.replace("\n", "\033[33m*\033[m\n", count=1)
            else:
                output = output.replace("\n", " \n", count=1)
            return output + "\n"

        try:
            # Embedded file:
            with open(path) as f:
                contents = f.read()
        except FileNotFoundError:
            return f"\n\033[31;1m<File not found: {element.dest}>\033[m\n"

        extension = path.rpartition(".")[2] if "." in path else ""
        try:
            lexer = get_lexer_by_name(extension, stripall=True)
        except ClassNotFound:
            code = contents
        else:
            code = highlight(contents, lexer, FORMATTER)

        title = self.render_children(element) or path
        heading = f"\033[1;36;7m{title:^{TerminalRenderer.width}}\033[22;27m"
        return "\n" + heading + "\n" + boxed(code, line_numbers=True, box_color="\033[36m", min_width=TerminalRenderer.width) + "\n\n"

    def render_link(self, element) -> str:
        title = self.render_children(element) or element.dest
        return f"\033[{'1;' if element is highlighted_element else ''}4;34m{title}\033[m"

    def render_emphasis(self, element) -> str:
        return f"\033[3m{self.render_children(element)}\033[23m"

    def render_strong_emphasis(self, element) -> str:
        return f"\033[1m{self.render_children(element)}\033[22m"

    def render_strikethrough(self, element) -> str:
        return f"\033[9m{self.render_children(element)}\033[29m"

    def render_code_span(self, element) -> str:
        return f"\033[1;32;48;2;40;50;40m{element.children}\033[22;39;49m"

    def render_raw_text(self, element) -> str:
        assert(isinstance(element.children, str))
        return str(element.children)

    def render_literal(self, element) -> str:
        return self.render_raw_text(element)

    def render_code_block(self, element) -> str:
        raw_code = element.children[0].children
        if element.lang == "run":
            lexer = get_lexer_by_name("bash", stripall=True)
            code = highlight(raw_code, lexer, FORMATTER)
            output = subprocess.check_output(
                ["bash", "-c", raw_code.strip()],
                stdin=open("/dev/null", "r"),
                cwd=os.path.dirname(TerminalRenderer.relative_filename) or '.',
            ).decode("utf-8").rstrip("\n")
            return boxed("\033[33;1m$\033[m " + code + "\n" + output, line_numbers=False, box_color="\033[33m", min_width=TerminalRenderer.width) + "\n\n"
        elif element.lang == "demo":
            lexer = get_lexer_by_name("bash", stripall=True)
            code = highlight(raw_code, lexer, FORMATTER)
            title = "Demo (press Enter to run)" if element is highlighted_element else "Demo"
            heading = f"\033[1;32;7m{title:^{TerminalRenderer.width}}\033[22;27m"
            return heading + "\n" + boxed("\033[33;1m$\033[m " + code, line_numbers=False, box_color="\033[32m", min_width=TerminalRenderer.width) + "\n\n"

        code = raw_code
        assert(isinstance(code, str))
        try:
            lexer = get_lexer_by_name(element.lang, stripall=True)
        except ClassNotFound:
            pass
        else:
            code = highlight(code, lexer, FORMATTER)

        return boxed(code, line_numbers=True, box_color="\033[34m", min_width=TerminalRenderer.width) + "\n\n"

    def render_fenced_code(self, element) -> str:
        return self.render_code_block(element)

    def render_quote(self, element) -> str:
        return f"\033[34;3m{self.render_children(element)}\033[39;23m"

    def render_paragraph(self, element) -> str:
        return f"{self.render_children(element).strip()}\n\n"

def get_demos(element) -> list:
    if isinstance(element, (marko.block.CodeBlock, marko.block.FencedCode)):
        if element.lang == "demo":
            def demo():
                raw_code = element.children[0].children
                subprocess.run(
                    ["bash", "-c", raw_code.strip()],
                    cwd=os.path.dirname(TerminalRenderer.relative_filename) or '.',
                )
            return [Demo(element, demo)]
    elif isinstance(element, marko.inline.Link):
        def demo():
            webbrowser.open(element.dest, new=1)
        return [Demo(element, demo)]
    elif isinstance(element, marko.inline.Image):
        path = element.dest if os.path.isabs(element.dest) else os.path.join(os.path.dirname(TerminalRenderer.relative_filename), element.dest)
        if is_image(path):
            return [Demo(element, lambda: PIL.Image.open(path).show())]
    elif isinstance(element, marko.element.Element):
        if hasattr(element, "children"):
            demos = []
            for child in element.children:
                demos += get_demos(child)
            return demos
        else:
            raise ValueError(f"No children! {element}")
    elif not isinstance(element, str):
        raise ValueError(f"Not an element! {element}")
    return []

markdown = marko.Markdown(renderer=TerminalRenderer)

def show_slide(bt:btui.BTUI, slides:[Slide], index:int, *, scroll=0, raw=False, demo_index=0) -> int:
    global highlighted_element
    slide = slides[index]
    with bt.buffered():
        bt.clear()

        if raw:
            lexer = get_lexer_by_name("markdown", stripall=True)
            code = highlight(slide.text, lexer, FORMATTER)
            for i,line in enumerate(code.splitlines()):
                bt.move(0, i)
                bt.write(line)
            return

        if slide.text.strip():
            TerminalRenderer.relative_filename = slide.filename
            ast = markdown.parse(slide.text)

            demos = get_demos(ast)
            highlighted_element = demos[demo_index].element if demos else None

            TerminalRenderer.width = bt.width//4
            rendered = markdown.render(ast)
            TerminalRenderer.width = max(render_width(line) for line in rendered.splitlines())
            rendered = markdown.render(ast)

            lines = rendered.splitlines()
            width = max(render_width(line) for line in lines)
            height = len(lines)

            x = max(0, (bt.width - width)//2)
            y = max(0, (bt.height - height)//2) - scroll
            for i,line in enumerate(rendered.splitlines()):
                if y + i in range(bt.height):
                    bt.move(x, y + i)
                    bt.write(line)
        else:
            width,height = 0,0

        pos_str = f"{index+1}/{len(slides)}"
        bt.move(bt.width-len(pos_str), bt.height)
        with bt.attributes("dim"):
            bt.write(pos_str)

    return height

def draw_time(bt:btui.BTUI, start_time:float):
    elapsed = time.perf_counter() - start_time
    bt.move(0, terminal_height-1)
    with bt.attributes("dim"):
        if elapsed >= 3600:
            bt.write(f"    {int(elapsed//3600)}:{int((elapsed % 3600)//60):02}:{int(elapsed % 60):02}")
        else:
            bt.write(f"    {int(elapsed//60):2}:{int(elapsed % 60):02}")

def present(slides:[str]):
    global terminal_width, terminal_height
    redraw = True
    index, prev_index = 0, None
    raw = False
    scroll = 0
    render_height = 0
    search = ''
    start_time = time.perf_counter()
    with btui.open() as bt:
        terminal_width, terminal_height = bt.width, bt.height
        key = None
        while key != 'q' and key != 'Ctrl-c':
            if index != prev_index:
                redraw = True
                scroll = 0

                ast = markdown.parse(slides[index].text)
                demos = get_demos(ast)
                demo_index = 0

            if redraw:
                render_height = show_slide(bt, slides, index, scroll=scroll, raw=raw, demo_index=demo_index)
                draw_time(bt, start_time)
                redraw = False
                prev_index = index

            key, mx, my = bt.getkey(10)

            draw_time(bt, start_time)

            if key is None:
                pass
            elif key == 'Left' or key == 'k' or key == 'Backspace':
                index = max(0, index - 1)
            elif key == 'Right' or key == 'Space' or key == 'j':
                index = min(len(slides)-1, index + 1)
            elif key == "Up" or key == "Mouse wheel up":
                redraw = True
                scroll = max(0, scroll-1)
            elif key == "Ctrl-u":
                redraw = True
                scroll = max(0, scroll-10)
            elif key == "Down" or key == "Mouse wheel down":
                scroll = min(scroll+1, max(0, render_height-bt.height-1))
                redraw = True
            elif key == "Ctrl-d":
                scroll = min(scroll+10, max(0, render_height-bt.height-1))
                redraw = True
            elif key == 'Ctrl-r' or key == 'r':
                redraw = True
            elif key == 'Home' or key == 'h':
                index = 0
            elif key == 'End' or key == 'l':
                index = len(slides)-1
            elif key == 'Ctrl-z':
                bt.suspend()
                redraw = True
            elif key == 'Enter':
                if len(demos) > 0:
                    with bt.disabled():
                        bt.flush()
                        # Clear screen and move to top:
                        print('\033[2J\033[H', flush=True, end="")
                        demos[demo_index]()
                        if demo_index + 1 < len(demos):
                            demo_index += 1
                    redraw = True
            elif key == 'Tab':
                if demo_index + 1 < len(demos):
                    demo_index += 1
                    redraw = True
            elif key == 'Shift-Tab':
                if demo_index > 0:
                    demo_index -= 1
                    redraw = True
            elif key == '`':
                raw = not raw
                redraw = True
            elif key == "Resize":
                terminal_width, terminal_height = bt.width, bt.height
                redraw = True
            elif key in '0123456789':
                bt.move(1, bt.height)
                with bt.attributes("bold"):
                    bt.write("Go to slide: ")
                index_str = ''
                while key in '0123456789':
                    bt.write(key)
                    index_str += key
                    key, mx, my = bt.getkey()

                if key == 'Enter':
                    index = max(0, min(len(slides)-1, int(index_str)-1))
            elif key == '/':
                bt.move(1, bt.height)
                with bt.attributes("bold"):
                    bt.write("Go to slide: ")

                search = ''
                key, mx, my = bt.getkey()
                while key not in ('Ctrl-c', 'Enter'):
                    if key == 'Backspace':
                        if search:
                            search = search[:-1]
                            bt.write('\b \b')
                    else:
                        search += key
                        bt.write(key)
                    key, mx, my = bt.getkey()

                if key == 'Enter':
                    for offset in range(len(slides)):
                        if search.lower() in slides[(index + 1 + offset) % len(slides)].text.lower():
                            index = (index + 1 + offset) % len(slides)
                            break
            elif key == 'n': # Next search result
                for offset in range(len(slides)):
                    if search.lower() in slides[(index + 1 + offset) % len(slides)].text.lower():
                        index = (index + 1 + offset) % len(slides)
                        break
            elif key == 'p': # Previous search result
                for offset in range(len(slides)):
                    if search.lower() in slides[(index - 1 - offset + 2*len(slides)) % len(slides)].text.lower():
                        index = (index - 1 - offset + 2*len(slides)) % len(slides)
                        break

if __name__ == "__main__":
    import sys
    if len(sys.argv) < 2:
        print(f"Usage: {sys.argv[0]} file1.slides [file2.slides...]")
        sys.exit(1)


    slides = []
    for filename in sys.argv[1:]:
        try:
            with open(filename) as f:
                text = f.read()
                if any(filename.endswith(ext) for ext in (".slides", ".md", ".txt")):
                    if text.startswith("#!"):
                        _,text = text.split('\n', maxsplit=1)
                    slides += [Slide(filename, slide.strip()) for slide in re.split(r'(?m)^\-{3,}$', text)]
                else:
                    extension = filename.rpartition(".")[2] if "." in filename else ""
                    slides += [Slide(filename, f"```{extension}\n{text.strip()}\n```")]
        except FileNotFoundError:
            print(f"File not found: {filename}")
            sys.exit(1)
    present(slides)