import calendar
import json
from datetime import datetime
from io import BytesIO
from pathlib import Path
from zoneinfo import ZoneInfo

from PIL import Image, ImageDraw, ImageFont, ImageOps

from pigway_frame_flow.errors import ErrorCode as E
from pigway_frame_flow.errors import FlowError


class TemplateRenderer:
    def __init__(self, db, settings, weather, assets):
        self.db, self.settings, self.weather, self.assets = (
            db,
            settings,
            weather,
            assets,
        )
        self.root = Path(__file__).resolve().parent.parent / "templates"

    def info(self, template_id):
        path = self.root / (template_id + ".json")
        if not path.exists() or path.parent != self.root:
            raise FlowError(E.NOT_FOUND, "Template not found", 404)
        spec = json.loads(path.read_text())
        config = self.db.one(
            "SELECT payload FROM template_config WHERE template_id=?", (template_id,)
        )
        if config:
            spec["defaults"].update(json.loads(config["payload"]))
        return spec

    def list(self):
        return [self.info(p.stem) for p in sorted(self.root.glob("*.json"))]

    def font(self, size):
        for path in [
            self.settings.font_path,
            "/System/Library/Fonts/PingFang.ttc",
            "/usr/share/fonts/truetype/dejavu/DejaVuSans.ttf",
        ]:
            if Path(path).is_file():
                return ImageFont.truetype(path, size)
        return ImageFont.load_default(size=size)

    def resolve(self, template_id, data):
        spec = self.info(template_id)
        conf = self.db.one(
            "SELECT payload FROM template_config WHERE template_id=?", (template_id,)
        )
        values = dict(spec["defaults"])
        if conf:
            values.update(json.loads(conf["payload"]))
        values.update(data)
        current = datetime.now(ZoneInfo(self.settings.timezone))
        values.setdefault("date", current.strftime("%Y-%m-%d"))
        values.setdefault(
            "weekday",
            [
                "星期一 / Monday",
                "星期二 / Tuesday",
                "星期三 / Wednesday",
                "星期四 / Thursday",
                "星期五 / Friday",
                "星期六 / Saturday",
                "星期日 / Sunday",
            ][current.weekday()],
        )
        if "weather" not in values:
            values["weather"] = self.weather.get_current()
        values["updated"] = current.strftime("%Y-%m-%d %H:%M")
        values["weather_attribution"] = (
            values.get("weather", {}).get("attribution", "")
            if isinstance(values.get("weather"), dict)
            else ""
        )
        return values

    def render(self, template_id, data, profile="color"):
        spec = self.info(template_id)
        values = self.resolve(template_id, data)
        current = datetime.now(ZoneInfo(self.settings.timezone))
        img = Image.new("RGB", (1200, 1600), "white")
        draw = ImageDraw.Draw(img)
        accent = "#184d42" if profile == "color" else "#000000"

        def text(value, x, y, width, height, size):
            font = self.font(size)
            lines, line = [], ""
            for char in str(value)[:3000]:
                if char == "\n" or draw.textlength(line + char, font=font) > width:
                    lines.append(line)
                    line = "" if char == "\n" else char
                else:
                    line += char
            lines.append(line)
            maxlines = max(1, height // (size + 14))
            for n, line in enumerate(lines[:maxlines]):
                if n == maxlines - 1 and len(lines) > maxlines:
                    line = line[:-2] + "…"
                draw.text(
                    (x, y + n * (size + 14)),
                    line,
                    font=font,
                    fill=accent if size >= 60 else "black",
                )

        for block in spec["blocks"]:
            x, y, w, h = block["box"]
            if block["kind"] == "rule":
                draw.rectangle((x, y, x + w, y + h), fill=accent)
            elif block["kind"] == "month":
                try:
                    shown = datetime.strptime(str(values["date"]), "%Y-%m-%d")
                except ValueError:
                    raise FlowError(
                        E.INVALID_REQUEST, "Calendar date must be YYYY-MM-DD"
                    ) from None
                text(shown.strftime("%Y-%m"), x, y, w, 70, 48)
                cells = calendar.Calendar(firstweekday=0).monthdayscalendar(
                    shown.year, shown.month
                )
                cell_w, cell_h = w // 7, (h - 140) // len(cells)
                for col, label in enumerate(
                    ["一 M", "二 T", "三 W", "四 T", "五 F", "六 S", "日 S"]
                ):
                    text(label, x + col * cell_w + 10, y + 80, cell_w - 20, 60, 30)
                for row, week in enumerate(cells):
                    for col, day in enumerate(week):
                        if not day:
                            continue
                        left, top = x + col * cell_w, y + 140 + row * cell_h
                        if (shown.year, shown.month, day) == (
                            current.year,
                            current.month,
                            current.day,
                        ):
                            draw.rectangle(
                                (left, top, left + cell_w - 6, top + cell_h - 6),
                                outline=accent,
                                width=5,
                            )
                        text(day, left + 25, top + 10, cell_w - 35, cell_h, 38)
            elif block["kind"] == "photo":
                asset_id = values.get("photo_id")
                if asset_id:
                    with Image.open(self.assets.path(asset_id)) as photo:
                        img.paste(ImageOps.fit(photo.convert("RGB"), (w, h)), (x, y))
                else:
                    draw.rectangle((x, y, x + w, y + h), outline="black", width=5)
                    text(
                        "家庭照片 / Family photo",
                        x + 35,
                        y + h // 2 - 30,
                        w - 70,
                        100,
                        36,
                    )
            else:
                value = values.get(block.get("field"), block.get("text", ""))
                if isinstance(value, list):
                    value = "\n".join(
                        "• "
                        + (str(v.get("title", "")) if isinstance(v, dict) else str(v))
                        for v in value[:10]
                    )
                if isinstance(value, dict):
                    if block.get("field") == "weather":
                        value = " · ".join(
                            str(value.get(k, ""))
                            for k in ["location", "temperature", "summary"]
                        )
                        if values["weather"].get("stale"):
                            value += " · 数据过期 / Stale"
                    else:
                        value = " · ".join(
                            str(v) for k, v in value.items() if k != "mock"
                        )
                text(value, x, y, w, h, block.get("size", 40))
        if profile == "grayscale":
            img = ImageOps.grayscale(img).convert("RGB")
        out = BytesIO()
        img.save(out, "JPEG", quality=93)
        return out.getvalue()