import os
from datetime import datetime
from flask import Flask, render_template, redirect, url_for, request, flash

from db import get_db, init_db

# =====================================================
# Constants
# =====================================================
STATUS_VALUES = ("not-started", "in-progress", "done")

# =====================================================
# Flask App Factory
# =====================================================

def create_app(test_config: dict | None = None) -> Flask:
    """
    Skapar och konfigurerar Flask-applikationen.
    Används både för runtime och tester.
    """
    app = Flask(__name__)
    app.secret_key = os.environ.get("FLASK_SECRET_KEY", "dev-secret")

    # -------------------------------------------------
    # App Configuration
    # -------------------------------------------------
    default_db = os.path.join(os.path.dirname(__file__), "todo.db")
    app.config.update(
        DB_PATH=default_db,
        TESTING=False,
    )

    if test_config:
        app.config.update(test_config)

    # -------------------------------------------------
    # Initiera databasen
    # -------------------------------------------------
    init_db(app)

    # =================================================
    # Routes
    # =================================================

    @app.route("/")
    def index():
        """
        Root → redirect till dashboard
        """
        return redirect(url_for("dashboard"))

    @app.route("/dashboard", methods=["GET"])
    def dashboard():
        """
        Visar alla todos
        """
        with get_db(app) as conn:
            rows = conn.execute(
                """
                SELECT * FROM todo
                ORDER BY
                  CASE status
                    WHEN 'not-started' THEN 1
                    WHEN 'in-progress' THEN 2
                    ELSE 3
                  END,
                  id DESC
                """
            ).fetchall()

        return render_template(
            "index.html",
            todos=rows,
            status_values=STATUS_VALUES,
        )

    @app.route("/todo/create", methods=["POST"])
    def create_todo():
        """
        Skapar en ny todo
        """
        title = (request.form.get("title") or "").strip()
        description = (request.form.get("description") or "").strip()
        status = request.form.get("status") or "not-started"

        if not title or not description:
            flash("Title och description krävs.", "danger")
            return redirect(url_for("dashboard"))

        if status not in STATUS_VALUES:
            status = "not-started"

        now = datetime.now().isoformat(timespec="seconds")

        with get_db(app) as conn:
            conn.execute(
                """
                INSERT INTO todo (title, description, status, created)
                VALUES (?, ?, ?, ?)
                """,
                (title, description, status, now),
            )

        flash("Todo skapad!", "success")
        return redirect(url_for("dashboard"))

    @app.route("/todo/<int:todo_id>/status", methods=["POST"])
    def update_status(todo_id: int):
        """
        Uppdaterar status på en todo
        """
        status = request.form.get("status")

        if status not in STATUS_VALUES:
            flash("Ogiltig status.", "danger")
            return redirect(url_for("dashboard"))

        now = datetime.now().isoformat(timespec="seconds")

        with get_db(app) as conn:
            cur = conn.execute(
                """
                UPDATE todo
                SET status = ?, edited = ?
                WHERE id = ?
                """,
                (status, now, todo_id),
            )

        flash(
            "Status uppdaterad." if cur.rowcount else "Todo hittades inte.",
            "success" if cur.rowcount else "danger",
        )

        return redirect(url_for("dashboard"))

    @app.route("/todo/<int:todo_id>/delete", methods=["POST"])
    def delete_todo(todo_id: int):
        """
        Tar bort en todo
        """
        with get_db(app) as conn:
            cur = conn.execute(
                "DELETE FROM todo WHERE id = ?",
                (todo_id,),
            )

        flash(
            "Todo borttagen." if cur.rowcount else "Todo hittades inte.",
            "success" if cur.rowcount else "danger",
        )

        return redirect(url_for("dashboard"))

    return app

# =====================================================
# Main
# =====================================================

if __name__ == "__main__":
    app = create_app()
    app.run(host="127.0.0.1", port=5001, debug=True)