MainFX session indicator

Script Title: MainFX Session Indicator with Customizable Lines

Overview:
This script is designed to help traders visually identify key market sessions on their TradingView charts. It marks both the opening and closing of major sessions (Frankfurt, London, New York, Sydney, and Tokyo) by drawing lines and labels on the chart. The indicator is highly customizable, allowing you to define specific session times, choose your preferred time zone, and adjust the visual appearance of all lines.

Key Features:

Custom Session Times:
Each session’s start and end times are defined by user inputs in a simple HHMM-HHMM format. This means you can adjust the sessions to match the exact market hours you follow, making the indicator flexible for different trading strategies and markets.

Time Zone Flexibility:
The "Chart/Local Time Zone" input lets you override the default time zone of your chart. By setting a specific time zone (e.g., "Africa/Lagos" or "Africa/Accra"), the script calculates session start and end events relative to that zone. This ensures that, regardless of where you are trading from, the session markers accurately reflect the intended market hours and adjust automatically for Daylight Saving Time if applicable.

Open Range Levels (ORH/ORL):
When a session opens or closes, the script draws horizontal lines at the high and low of the candle immediately before the event. These levels act as the Open Range High (ORH) and Open Range Low (ORL) markers. They serve as key reference points for traders to gauge price levels established just before a session change.

Customizable Visuals:
Every visual element is customizable. You can adjust the color, width, and style (defaulting to a dotted line) of both the ORH/ORL lines and the combined session lines that label open and close events. This allows you to tailor the indicator to match your charting style and ensure that the lines stand out clearly.

Session Event Detection:
The script utilizes helper functions to check each bar on the chart. It compares the current bar’s session status with that of the previous bar to determine whether a session has just started or ended. When such a transition is detected, it triggers the drawing of the appropriate lines and labels.

Optimized for Intraday Trading:
Since the script’s functionality is based on minute-level bar changes, it is best used on 1-minute or lower timeframes. This ensures precision in marking the exact moments when sessions transition, which is critical for intraday trading strategies.

How It Works:

Session Timing:
The script calculates the session periods using the time() function with the user-defined session strings and time zone. This makes it independent of the chart’s inherent time settings.

Event Triggering:
When the current bar transitions into or out of a session (i.e., the session status changes between bars), the script detects this change. It then draws horizontal lines at the previous candle’s high and low (marking ORH and ORL) and adds session labels for clarity.

Visual Customization:
Users can easily change the appearance of the drawn lines and session labels via the script’s input options, ensuring that the indicators are both aesthetically pleasing and functionally clear.

Usage:

For Traders:
Use this indicator to keep track of critical market sessions and to spot participants in the session.
Customization:
Adjust session times and the time zone to suit your local market or the specific market you are analyzing.
Visual Clarity:
Customize line styles to ensure that your chart remains clear and that the session markers are easy to interpret even during overlapping sessions.