#
# Based on code from https://github.com/openai/whisper
#

import os
import json
import re
from typing import Callable, TextIO, Optional


def format_timestamp(
    seconds: float, always_include_hours: bool = False, decimal_marker: str = "."
):
    assert seconds >= 0, "non-negative timestamp expected"
    milliseconds = round(seconds * 1000.0)

    hours = milliseconds // 3_600_000
    milliseconds -= hours * 3_600_000

    minutes = milliseconds // 60_000
    milliseconds -= minutes * 60_000

    seconds = milliseconds // 1_000
    milliseconds -= seconds * 1_000

    hours_marker = f"{hours:02d}:" if always_include_hours or hours > 0 else ""
    return (
        f"{hours_marker}{minutes:02d}:{seconds:02d}{decimal_marker}{milliseconds:03d}"
    )


class ResultWriter:
    extension: str

    def __init__(self, output_dir: str):
        self.output_dir = output_dir

    def __call__(self, result: dict, audio_path: str, options: dict):
        audio_basename = os.path.basename(audio_path)
        audio_basename = os.path.splitext(audio_basename)[0]
        output_path = os.path.join(
            self.output_dir, audio_basename + "." + self.extension
        )

        with open(output_path, "w", encoding="utf-8") as f:
            self.write_result(result, f, options)

    def write_result(self, result: dict, file: TextIO, options: dict):
        raise NotImplementedError


class SubtitlesWriter(ResultWriter):
    always_include_hours: bool
    decimal_marker: str

    def iterate_result(self, result: dict, options: dict):
        raw_max_line_width: Optional[int] = options.get("max_line_width", None)
        max_line_count: Optional[int] = options.get("max_line_count", None)
        highlight_words = options.get("highlight_words", False)
        max_line_width = 1000 if raw_max_line_width is None else raw_max_line_width
        preserve_segments = max_line_count is None or raw_max_line_width is None

        def iterate_subtitles():
            line_len = 0
            line_count = 1
            # the next subtitle to yield (a list of word timings with whitespace)
            subtitle: list[dict] = []
            last = result["segments"][0]["words"][0]["start"]
            for segment in result["segments"]:
                for i, original_timing in enumerate(segment["words"]):
                    timing = original_timing.copy()
                    long_pause = not preserve_segments and timing["start"] - last > 3.0
                    has_room = line_len + len(timing["word"]) <= max_line_width
                    seg_break = i == 0 and len(subtitle) > 0 and preserve_segments
                    if line_len > 0 and has_room and not long_pause and not seg_break:
                        # line continuation
                        line_len += len(timing["word"])
                    else:
                        # new line
                        timing["word"] = timing["word"].strip()
                        if (
                            len(subtitle) > 0
                            and max_line_count is not None
                            and (long_pause or line_count >= max_line_count)
                            or seg_break
                        ):
                            # subtitle break
                            yield subtitle
                            subtitle = []
                            line_count = 1
                        elif line_len > 0:
                            # line break
                            line_count += 1
                            timing["word"] = "\n" + timing["word"]
                        line_len = len(timing["word"].strip())
                    subtitle.append(timing)
                    last = timing["start"]
            if len(subtitle) > 0:
                yield subtitle

        if (
            len(result["segments"]) > 0
            and "words" in result["segments"][0]
            and result["segments"][0]["words"]
        ):
            for subtitle in iterate_subtitles():
                subtitle_start = self.format_timestamp(subtitle[0]["start"])
                subtitle_end = self.format_timestamp(subtitle[-1]["end"])
                subtitle_text = "".join([word["word"] for word in subtitle])
                if highlight_words:
                    last = subtitle_start
                    all_words = [timing["word"] for timing in subtitle]
                    for i, this_word in enumerate(subtitle):
                        start = self.format_timestamp(this_word["start"])
                        end = self.format_timestamp(this_word["end"])
                        if last != start:
                            yield last, start, subtitle_text

                        yield start, end, "".join(
                            [
                                re.sub(r"^(\s*)(.*)$", r"\1<u>\2</u>", word)
                                if j == i
                                else word
                                for j, word in enumerate(all_words)
                            ]
                        )
                        last = end
                else:
                    yield subtitle_start, subtitle_end, subtitle_text
        else:
            for segment in result["segments"]:
                segment_start = self.format_timestamp(segment["start"])
                segment_end = self.format_timestamp(segment["end"])
                segment_text = segment["text"].strip().replace("-->", "->")
                yield segment_start, segment_end, segment_text

    def format_timestamp(self, seconds: float):
        return format_timestamp(
            seconds=seconds,
            always_include_hours=self.always_include_hours,
            decimal_marker=self.decimal_marker,
        )


class SubtitlesWriter_ref(ResultWriter):
    always_include_hours: bool
    decimal_marker: str

    def iterate_result(self, result: dict, options: dict):
        for segment in result["segments"]:
            segment_start = self.format_timestamp(segment["start"])
            segment_end = self.format_timestamp(segment["end"])
            segment_text = segment["text"].strip().replace("-->", "->")
            highlight = options.get("highlight_words", False)

            if word_timings := segment["words"]:
                all_words = [timing["word"] for timing in word_timings]
                all_words[0] = all_words[0].strip()  # remove the leading space, if any
                last = segment_start
                for i, this_word in enumerate(word_timings):
                    start = self.format_timestamp(this_word["start"])
                    end = self.format_timestamp(this_word["end"])
                    if last != start:
                        yield last, start, segment_text

                    yield start, end, "".join(
                        [
                            f"<u>{word}</u>" if j == i and highlight else word
                            for j, word in enumerate(all_words)
                        ]
                    )
                    last = end

                if last != segment_end:
                    yield last, segment_end, segment_text
            else:
                yield segment_start, segment_end, segment_text

    def format_timestamp(self, seconds: float):
        return format_timestamp(
            seconds=seconds,
            always_include_hours=self.always_include_hours,
            decimal_marker=self.decimal_marker,
        )


class WriteTXT(ResultWriter):
    extension: str = "txt"

    def write_result(self, result: dict, file: TextIO, options: dict):
        for segment in result["segments"]:
            print(segment["text"].strip(), file=file, flush=True)


class WriteSRT(SubtitlesWriter):
    extension: str = "srt"
    always_include_hours: bool = True
    decimal_marker: str = ","

    def write_result(self, result: dict, file: TextIO, options: dict):
        for i, (start, end, text) in enumerate(
            self.iterate_result(result, options), start=1
        ):
            print(f"{i}\n{start} --> {end}\n{text}\n", file=file, flush=True)


class WriteVTT(SubtitlesWriter):
    extension: str = "vtt"
    always_include_hours: bool = False
    decimal_marker: str = "."

    def write_result(self, result: dict, file: TextIO, options: dict):
        print("WEBVTT\n", file=file)
        for start, end, text in self.iterate_result(result, options):
            print(f"{start} --> {end}\n{text}\n", file=file, flush=True)


class WriteTSV(ResultWriter):
    """
    Write a transcript to a file in TSV (tab-separated values) format containing lines like:
    <start time in integer milliseconds>\t<end time in integer milliseconds>\t<transcript text>

    Using integer milliseconds as start and end times means there's no chance of interference from
    an environment setting a language encoding that causes the decimal in a floating point number
    to appear as a comma; also is faster and more efficient to parse & store, e.g., in C++.
    """

    extension: str = "tsv"

    def write_result(self, result: dict, file: TextIO, options: dict):
        print("start", "end", "text", sep="\t", file=file)
        for segment in result["segments"]:
            print(round(1000 * segment["start"]), file=file, end="\t")
            print(round(1000 * segment["end"]), file=file, end="\t")
            print(segment["text"].strip().replace("\t", " "), file=file, flush=True)


class WriteJSON(ResultWriter):
    extension: str = "json"

    def write_result(self, result: dict, file: TextIO, options: dict):
        pretty_json: bool = options.get("pretty_json", False)

        if pretty_json:
            json.dump(result, file, indent=4, ensure_ascii=False)
        else:
            json.dump(result, file)


def get_writer(
    output_format: str, output_dir: str
) -> Callable[[dict, TextIO, dict], None]:
    writers = {
        "txt": WriteTXT,
        "vtt": WriteVTT,
        "srt": WriteSRT,
        "tsv": WriteTSV,
        "json": WriteJSON,
    }

    if output_format == "all":
        all_writers = [writer(output_dir) for writer in writers.values()]

        def write_all(result: dict, file: TextIO, options: dict):
            for writer in all_writers:
                writer(result, file, options)

        return write_all

    return writers[output_format](output_dir)
