from flask_wtf import FlaskForm
from wtforms import IntegerField, SelectField, StringField, SubmitField, TextAreaField
from wtforms.fields import DateTimeLocalField
from wtforms.validators import Length, NumberRange, Optional, ValidationError

from .models import TASK_PRIORITIES, TASK_STATUSES


STATUS_LABELS = {
    "not_started": "Not started",
    "in_progress": "In progress",
    "done": "Done",
}
PRIORITY_LABELS = {
    "urgent": "Urgent",
    "important": "Important",
    "normal": "Normal",
}


def not_blank(_form: FlaskForm, field: StringField) -> None:
    if not field.data or not field.data.strip():
        raise ValidationError("This field cannot be blank.")


class TaskForm(FlaskForm):
    title = StringField(
        "Task title",
        validators=[not_blank, Length(max=200)],
    )
    description = TextAreaField(
        "Notes",
        validators=[Optional(), Length(max=5000)],
    )
    status = SelectField(
        "Status",
        choices=[(value, STATUS_LABELS[value]) for value in TASK_STATUSES],
        default="not_started",
    )
    priority = SelectField(
        "Priority",
        choices=[(value, PRIORITY_LABELS[value]) for value in TASK_PRIORITIES],
        default="normal",
    )
    due_date = DateTimeLocalField(
        "Due date and time",
        format="%Y-%m-%dT%H:%M",
        validators=[Optional()],
    )
    submit = SubmitField("Save task")


class SubtaskForm(FlaskForm):
    title = StringField(
        "Next small step",
        validators=[not_blank, Length(max=100)],
    )
    submit = SubmitField("Add step")


class ActionForm(FlaskForm):
    submit = SubmitField()


def valid_chunk_plan(_form: FlaskForm, field: StringField) -> None:
    if not field.data or not field.data.strip():
        return
    values = [value.strip() for value in field.data.split(",")]
    if len(values) > 12:
        raise ValidationError("Use at most 12 focus blocks.")
    try:
        minutes = [int(value) for value in values]
    except ValueError as exc:
        raise ValidationError(
            "Use comma-separated whole minutes, such as 5, 5, 10."
        ) from exc
    if any(value < 1 or value > 120 for value in minutes):
        raise ValidationError("Each focus block must be 1 to 120 minutes.")


class FocusSettingsForm(FlaskForm):
    timer_minutes = IntegerField(
        "Countdown length in minutes",
        validators=[Optional(), NumberRange(min=1, max=180)],
    )
    context = StringField(
        "Helpful context",
        validators=[Optional(), Length(max=100)],
    )
    chunk_plan = StringField(
        "Focus blocks",
        validators=[Optional(), Length(max=120), valid_chunk_plan],
    )
    submit = SubmitField("Save focus setup")

    def parsed_chunks(self) -> list[int]:
        if not self.chunk_plan.data or not self.chunk_plan.data.strip():
            return []
        return [
            int(value.strip())
            for value in self.chunk_plan.data.split(",")
        ]