import sqlite3

import models
import ui


def log_weight(conn: sqlite3.Connection) -> None:
    ui.clear_screen()
    ui.print_header("Log Weight")
    date_time = ui.prompt_datetime("Date/Time")
    weight = ui.prompt_float("Weight (kg): ", min_val=0.1)
    assert weight is not None
    models.add_weight_log(conn, date_time, weight)
    print(f"Logged {weight:.1f}kg.")
    ui.pause()


def _fmt_diff(current: float, previous: float) -> str:
    diff = round(current - previous, 1)
    if diff > 0:
        return f"+{diff:.1f}"
    elif diff < 0:
        return f"{diff:.1f}"
    return "0.0"


def view_weight_logs(conn: sqlite3.Connection) -> None:
    while True:
        ui.clear_screen()
        logs = models.list_weight_logs(conn)
        if not logs:
            print("\nNo weight logs recorded yet.")
            ui.pause()
            return
        ui.print_header("Weight Logs")

        # Logs are newest-first; diff compares to the next row (previous in time)
        rows = []
        for i, log in enumerate(logs):
            weight = log["weight"]
            if i < len(logs) - 1:
                diff = _fmt_diff(weight, logs[i + 1]["weight"])
            else:
                diff = ""
            rows.append(
                [
                    str(i + 1),
                    log["date_time"],
                    f"{weight:.1f}",
                    diff,
                ]
            )

        ui.print_table(["#", "Date", "Weight (kg)", "Diff"], rows)

        choice = input("\nSelect # to delete ('b' = back): ").strip()
        if choice.lower() == "b":
            break
        try:
            idx = int(choice) - 1
            if idx < 0 or idx >= len(logs):
                print("Invalid selection.")
                continue
        except ValueError:
            print("Invalid input.")
            continue
        if ui.confirm(f"Delete log from {logs[idx]['date_time']}?"):
            models.delete_weight_log(conn, logs[idx]["id"])
            print("Log deleted.")
            ui.pause()