import requests
from dotenv import load_dotenv
import os
import pandas as pd # Import pandas

load_dotenv()

BLIZZ_CLIENT_ID = os.getenv("BLIZZ_CLIENT_ID")
BLIZZ_CLIENT_SECRET = os.getenv("BLIZZ_CLIENT_SECRET")

TOKEN_URL = "https://oauth.battle.net/token"
NAMESPACE = "profile-classic-us"
LOCALE = "en_US"

# Define CSV constants
CSV_ACHIEVEMENT_FILE_PATH = 'util/raid_achievements.csv'
CSV_ID_COLUMN_NAME = 'ID'
CSV_NAME_COLUMN_NAME = 'Name'

# Global store for pre-loaded CSV data and any loading error
RAID_ACHIEVEMENTS_DATA = None
CSV_LOAD_ERROR_MESSAGE = None

def _load_raid_achievements_from_csv():
    """Loads achievement data from the CSV file into a global variable once."""
    global RAID_ACHIEVEMENTS_DATA, CSV_LOAD_ERROR_MESSAGE
    try:
        df = pd.read_csv(CSV_ACHIEVEMENT_FILE_PATH)
        if CSV_ID_COLUMN_NAME not in df.columns or CSV_NAME_COLUMN_NAME not in df.columns:
            CSV_LOAD_ERROR_MESSAGE = f"Error: Required columns ('{CSV_ID_COLUMN_NAME}', '{CSV_NAME_COLUMN_NAME}') not found in {CSV_ACHIEVEMENT_FILE_PATH}."
            print(CSV_LOAD_ERROR_MESSAGE)
            RAID_ACHIEVEMENTS_DATA = [] # Ensure it's an empty list on column error
            return

        temp_list = []
        for index, row in df.iterrows():
            temp_list.append({
                'id': row[CSV_ID_COLUMN_NAME],
                'name': row[CSV_NAME_COLUMN_NAME]
            })
        RAID_ACHIEVEMENTS_DATA = temp_list
        print(f"Successfully loaded {len(RAID_ACHIEVEMENTS_DATA)} achievements from {CSV_ACHIEVEMENT_FILE_PATH} at startup.")
    except FileNotFoundError:
        CSV_LOAD_ERROR_MESSAGE = f"Error: CSV file {CSV_ACHIEVEMENT_FILE_PATH} not found at startup."
        print(CSV_LOAD_ERROR_MESSAGE)
        RAID_ACHIEVEMENTS_DATA = [] # Ensure it's an empty list on file not found
    except Exception as e:
        CSV_LOAD_ERROR_MESSAGE = f"An unexpected error occurred while loading {CSV_ACHIEVEMENT_FILE_PATH} at startup: {e}"
        print(CSV_LOAD_ERROR_MESSAGE)
        RAID_ACHIEVEMENTS_DATA = [] # Ensure it's an empty list on other errors

# Load CSV data when the module is imported
_load_raid_achievements_from_csv()

def get_token():
    '''Fetches an access token from the Battle.net API.'''
    if not BLIZZ_CLIENT_ID or not BLIZZ_CLIENT_SECRET:
        print("Error: CLIENT_ID or CLIENT_SECRET not found in .env file.")
        print("Please create a .env file in the project root with your credentials:")
        print("CLIENT_ID=\"YOUR_CLIENT_ID\"")
        print("CLIENT_SECRET=\"YOUR_CLIENT_SECRET\"")
        return None

    data = {
        "grant_type": "client_credentials"
    }
    auth = (BLIZZ_CLIENT_ID, BLIZZ_CLIENT_SECRET)

    try:
        response = requests.post(TOKEN_URL, data=data, auth=auth, timeout=10)
        response.raise_for_status()  # Raises an HTTPError for bad responses (4XX or 5XX)
        token_data = response.json()
        print("Access token fetched successfully!")
        # print(f"Token: {token_data.get('access_token')[:20]}...") # Print part of the token for brevity
        return token_data.get("access_token")
    except requests.exceptions.HTTPError as http_err:
        print(f"HTTP error occurred while fetching token: {http_err}")
        print(f"Response content: {response.content}")
    except requests.exceptions.RequestException as req_err:
        print(f"Request error occurred while fetching token: {req_err}")
    except Exception as e:
        print(f"An unexpected error occurred: {e}")
    return None

def get_raiders(access_token, realm, guild):
    '''Fetches a guild's roster from the Battle.net API and returns level 85 characters.'''
    # Sanitize realm and guild names for URL (simple lowercase and space to hyphen)
    realm_slug = realm.lower().replace(" ", "-")
    guild_slug = guild.lower().replace(" ", "-")

    url = f"https://us.api.blizzard.com/data/wow/guild/{realm_slug}/{guild_slug}/roster?namespace={NAMESPACE}&locale={LOCALE}"
    headers = {
        "Authorization": f"Bearer {access_token}"
    }

    try:
        response = requests.get(url, headers=headers, timeout=15)
        response.raise_for_status()  # Raise an exception for bad status codes
        
        roster_data = response.json()
        character_names = []

        if roster_data and 'members' in roster_data and isinstance(roster_data['members'], list):
            for member_entry in roster_data['members']:
                if isinstance(member_entry, dict) and 'character' in member_entry:
                    character = member_entry['character']
                    if isinstance(character, dict) and \
                       'name' in character and \
                       'level' in character and \
                       character['level'] == 85:
                        character_names.append(character['name'])
            
            if not character_names:
                return "No level 85 characters found in the guild."
            return character_names
        else:
            return "Could not find 'members' list in roster data, or the roster is empty. The guild might not exist or is not accessible."

    except requests.exceptions.HTTPError as http_err:
        if http_err.response.status_code == 404:
            return f"Error: Guild '{guild}' on realm '{realm}' not found (404)."
        return f"HTTP error occurred while fetching roster: {http_err} - {http_err.response.text}"
    except requests.exceptions.RequestException as req_err:
        return f"Request error occurred while fetching roster: {req_err}"
    except Exception as e:
        return f"An unexpected error occurred: {e}"

def get_char_achievements(access_token, realm, character):
    '''
    Fetches a character's achievements from the Battle.net API, 
    compares them against a predefined, pre-loaded CSV list of achievements, 
    and returns a comprehensive list indicating completion status for CSV achievements.
    '''
    global RAID_ACHIEVEMENTS_DATA, CSV_LOAD_ERROR_MESSAGE # Access globals

    # Check if CSV loading failed during startup
    if CSV_LOAD_ERROR_MESSAGE:
        # If CSV failed to load, we can't provide the comprehensive list.
        # Return an error reflecting this. The `data: []` part is for consistency.
        return {"error": True, "message": f"Prerequisite CSV data failed to load: {CSV_LOAD_ERROR_MESSAGE}", "data": []}
    
    if RAID_ACHIEVEMENTS_DATA is None or not RAID_ACHIEVEMENTS_DATA: # Should be initialized by _load_raid_achievements_from_csv
        # This case implies the CSV was empty or another issue post-initial load attempt.
        return {"error": True, "message": "Raid achievements list from CSV is unavailable or empty.", "data": []}

    realm_slug = realm.lower().replace(" ", "-")
    character_name_slug = character.lower()
    api_url = f"https://us.api.blizzard.com/profile/wow/character/{realm_slug}/{character_name_slug}/achievements?namespace={NAMESPACE}&locale={LOCALE}"
    headers = {"Authorization": f"Bearer {access_token}"}

    char_raw_achievements = None
    try:
        response = requests.get(api_url, headers=headers, timeout=15)
        response.raise_for_status()
        char_raw_achievements = response.json()
    except requests.exceptions.HTTPError as http_err:
        msg = f"HTTP error fetching achievements for {character} on {realm}: {http_err}"
        if http_err.response is not None: msg += f" - {http_err.response.text}"
        print(msg)
        # Even if API fails for char, we should still return the CSV list marked as incomplete
        # Or, indicate this specific character API fetch failed. For now, let's try to return CSV marked as incomplete.
        # This behavior might need adjustment based on desired user experience.
        comprehensive_status_list_on_api_error = []
        for ach_from_csv in RAID_ACHIEVEMENTS_DATA:
            comprehensive_status_list_on_api_error.append({
                'id': ach_from_csv['id'],
                'name': ach_from_csv['name'],
                'completed': False # Mark as false due to API error for this char
            })
        return {"error": True, "message": msg, "status_code": http_err.response.status_code if http_err.response else 500, "data_source": "csv_marked_incomplete", "achievements_list": comprehensive_status_list_on_api_error}
    except requests.exceptions.RequestException as req_err:
        msg = f"Request error fetching achievements for {character} on {realm}: {req_err}"
        print(msg)
        # Similar handling for request errors
        comprehensive_status_list_on_api_error = []
        for ach_from_csv in RAID_ACHIEVEMENTS_DATA:
            comprehensive_status_list_on_api_error.append({
                'id': ach_from_csv['id'],
                'name': ach_from_csv['name'],
                'completed': False
            })
        return {"error": True, "message": msg, "data_source": "csv_marked_incomplete", "achievements_list": comprehensive_status_list_on_api_error}
    except Exception as e:
        msg = f"Unexpected error fetching raw achievements for {character} on {realm}: {e}"
        print(msg)
        # Similar handling for unexpected errors
        comprehensive_status_list_on_api_error = []
        for ach_from_csv in RAID_ACHIEVEMENTS_DATA:
            comprehensive_status_list_on_api_error.append({
                'id': ach_from_csv['id'],
                'name': ach_from_csv['name'],
                'completed': False
            })
        return {"error": True, "message": msg, "data_source": "csv_marked_incomplete", "achievements_list": comprehensive_status_list_on_api_error}

    completed_char_achievement_ids = set()
    if char_raw_achievements and 'achievements' in char_raw_achievements and isinstance(char_raw_achievements['achievements'], list):
        for ach_details in char_raw_achievements['achievements']:
            if isinstance(ach_details, dict) and ach_details.get('id') is not None:
                completed_char_achievement_ids.add(ach_details.get('id'))
    else:
        print(f"Warning: Could not parse 'achievements' list from API for {character}. Assuming no achievements completed.")

    comprehensive_status_list = []
    for ach_from_csv in RAID_ACHIEVEMENTS_DATA: # Iterate over pre-loaded data
        is_completed = ach_from_csv['id'] in completed_char_achievement_ids
        comprehensive_status_list.append({
            'id': ach_from_csv['id'],
            'name': ach_from_csv['name'],
            'completed': is_completed
        })
    
    return comprehensive_status_list # Successful return

def calculate_achievement_completion_percentages(ach_data_by_character):
    """
    Analyzes a dictionary of character achievement statuses to determine completion percentages
    and lists of characters who have/haven't completed each achievement.

    Args:
        ach_data_by_character: A dictionary where keys are character names and values are 
                               lists of achievement statuses (output from get_char_achievements or 
                               the 'achievements_list' from an error object).
                               Each status dict: {'id': ach_id, 'name': ach_name, 'completed': True/False}.

    Returns:
        A list of dictionaries, where each dictionary contains:
        {'id': achievement_id, 'name': achievement_name, 'percentage_completed': float,
         'completed_by': [char_name1, ...], 'not_completed_by': [char_name2, ...]}
    """
    if not ach_data_by_character or not isinstance(ach_data_by_character, dict):
        print("Warning: Received invalid or empty input for percentage calculation.")
        return []

    achievement_details = {}
    # Example: achievement_details = {ach_id: {'name': 'Ach Name', 'completed_count': 0, 'completed_by': [], 'not_completed_by': []}}

    valid_character_names_for_count = []

    for char_name, char_ach_list in ach_data_by_character.items():
        if not isinstance(char_ach_list, list): # Skip if a character's data isn't a list
            print(f"Warning: Skipping non-list achievement data for character '{char_name}'. Type: {type(char_ach_list)}")
            continue
        
        valid_character_names_for_count.append(char_name) # Count this character as processed for denominator

        for ach_status in char_ach_list:
            ach_id = ach_status.get('id')
            ach_name = ach_status.get('name')

            if ach_id is None or ach_name is None: # Skip malformed entries
                continue

            if ach_id not in achievement_details:
                achievement_details[ach_id] = {
                    'name': ach_name,
                    'completed_count': 0,
                    'completed_by': [],
                    'not_completed_by': []
                }
            
            if ach_status.get('completed', False):
                achievement_details[ach_id]['completed_count'] += 1
                achievement_details[ach_id]['completed_by'].append(char_name)
            else:
                achievement_details[ach_id]['not_completed_by'].append(char_name)
    
    num_valid_characters = len(valid_character_names_for_count)
    if num_valid_characters == 0:
        print("Warning: No valid character achievement lists to process for percentages after filtering.")
        return []

    # Ensure all characters are in not_completed_by if they weren't in completed_by for an achievement
    # This handles cases where an achievement might not have been in a specific character's list for some reason,
    # though ideally each char_ach_list is comprehensive based on the CSV.
    # For robustness, we iterate through all known valid characters for each achievement.
    for ach_id in achievement_details:
        current_completed_by = set(achievement_details[ach_id]['completed_by'])
        # Rebuild not_completed_by based on all valid characters minus those who completed it
        achievement_details[ach_id]['not_completed_by'] = [ 
            name for name in valid_character_names_for_count if name not in current_completed_by
        ]

    result_summary = []
    for ach_id, details in achievement_details.items():
        percentage = (details['completed_count'] / num_valid_characters) * 100.0 if num_valid_characters > 0 else 0.0
        result_summary.append({
            'id': ach_id,
            'name': details['name'],
            'percentage_completed': round(percentage, 2),
            'completed_by': sorted(details['completed_by']), # Sort for consistent output
            'not_completed_by': sorted(details['not_completed_by']) # Sort for consistent output
        })
    
    result_summary.sort(key=lambda x: x['id']) # Sort by achievement ID

    return result_summary

def get_char_achievement_stats(access_token, realm, character):
    '''
    Fetches a character's achievements from the Battle.net API, 
    compares them against a predefined, pre-loaded CSV list of achievements, 
    and returns a comprehensive list indicating completion status for CSV achievements.
    '''
    global RAID_ACHIEVEMENTS_DATA, CSV_LOAD_ERROR_MESSAGE # Access globals

    # Check if CSV loading failed during startup
    if CSV_LOAD_ERROR_MESSAGE:
        # If CSV failed to load, we can't provide the comprehensive list.
        # Return an error reflecting this. The `data: []` part is for consistency.
        return {"error": True, "message": f"Prerequisite CSV data failed to load: {CSV_LOAD_ERROR_MESSAGE}", "data": []}
    
    if RAID_ACHIEVEMENTS_DATA is None or not RAID_ACHIEVEMENTS_DATA: # Should be initialized by _load_raid_achievements_from_csv
        # This case implies the CSV was empty or another issue post-initial load attempt.
        return {"error": True, "message": "Raid achievements list from CSV is unavailable or empty.", "data": []}

    realm_slug = realm.lower().replace(" ", "-")
    character_name_slug = character.lower()
    api_url = f"https://us.api.blizzard.com/profile/wow/character/{realm_slug}/{character_name_slug}/achievements?namespace={NAMESPACE}&locale={LOCALE}"
    headers = {"Authorization": f"Bearer {access_token}"}

    char_raw_achievements = None
    try:
        response = requests.get(api_url, headers=headers, timeout=15)
        response.raise_for_status()
        char_raw_achievements = response.json()
    except requests.exceptions.HTTPError as http_err:
        msg = f"HTTP error fetching achievements for {character} on {realm}: {http_err}"
        if http_err.response is not None: msg += f" - {http_err.response.text}"
        print(msg)
        # Even if API fails for char, we should still return the CSV list marked as incomplete
        # Or, indicate this specific character API fetch failed. For now, let's try to return CSV marked as incomplete.
        # This behavior might need adjustment based on desired user experience.
        comprehensive_status_list_on_api_error = []
        for ach_from_csv in RAID_ACHIEVEMENTS_DATA:
            comprehensive_status_list_on_api_error.append({
                'id': ach_from_csv['id'],
                'name': ach_from_csv['name'],
                'completed': False # Mark as false due to API error for this char
            })
        return {"error": True, "message": msg, "status_code": http_err.response.status_code if http_err.response else 500, "data_source": "csv_marked_incomplete", "achievements_list": comprehensive_status_list_on_api_error}
    except requests.exceptions.RequestException as req_err:
        msg = f"Request error fetching achievements for {character} on {realm}: {req_err}"
        print(msg)
        # Similar handling for request errors
        comprehensive_status_list_on_api_error = []
        for ach_from_csv in RAID_ACHIEVEMENTS_DATA:
            comprehensive_status_list_on_api_error.append({
                'id': ach_from_csv['id'],
                'name': ach_from_csv['name'],
                'completed': False
            })
        return {"error": True, "message": msg, "data_source": "csv_marked_incomplete", "achievements_list": comprehensive_status_list_on_api_error}
    except Exception as e:
        msg = f"Unexpected error fetching raw achievements for {character} on {realm}: {e}"
        print(msg)
        # Similar handling for unexpected errors
        comprehensive_status_list_on_api_error = []
        for ach_from_csv in RAID_ACHIEVEMENTS_DATA:
            comprehensive_status_list_on_api_error.append({
                'id': ach_from_csv['id'],
                'name': ach_from_csv['name'],
                'completed': False
            })
        return {"error": True, "message": msg, "data_source": "csv_marked_incomplete", "achievements_list": comprehensive_status_list_on_api_error}

    completed_char_achievement_ids = set()
    if char_raw_achievements and 'achievements' in char_raw_achievements and isinstance(char_raw_achievements['achievements'], list):
        for ach_details in char_raw_achievements['achievements']:
            if isinstance(ach_details, dict) and ach_details.get('id') is not None:
                completed_char_achievement_ids.add(ach_details.get('id'))
    else:
        print(f"Warning: Could not parse 'achievements' list from API for {character}. Assuming no achievements completed.")

    comprehensive_status_list = []
    for ach_from_csv in RAID_ACHIEVEMENTS_DATA: # Iterate over pre-loaded data
        is_completed = ach_from_csv['id'] in completed_char_achievement_ids
        comprehensive_status_list.append({
            'id': ach_from_csv['id'],
            'name': ach_from_csv['name'],
            'completed': is_completed
        })
    
    return comprehensive_status_list # Successful return