from django.http import HttpRequest, HttpResponse
from django.db.models.query import QuerySet

from openpyxl import Workbook
from openpyxl.styles import Font, PatternFill, Alignment, Border, Side
from openpyxl.utils import get_column_letter

from datetime import date, datetime
from typing import List

from ..models.weekpref import WeekPreference
from ..models.missions import Training
from ..models.hourbuildings import HourBuilding, HourBuildingLegFlight, HourBuildingLegStop, HourBuildingLegBase


def export_selected(request: HttpRequest, queryset: QuerySet[WeekPreference]) -> HttpResponse:

    if not queryset.first():
        raise Exception("Empty queryset")
    
    # Init Variables
    year = date.today().year
    week = queryset.first().week if queryset.first() else date.today().isocalendar().week
    weeks = queryset.order_by("week").distinct("week").all()
    
    # Prepare export filename and http content
    filename = f"{year}_week{'+'.join([str(w.week) for w in weeks])}_export.xlsx"
    response = HttpResponse(content_type='application/vnd.openxmlformats-officedocument.spreadsheetml.sheet')
    response['Content-Disposition'] = f'attachment; filename="{filename}"'

    # Create workbook and sheet
    wb = Workbook()
    ws = wb.active
    if not ws:
        raise Exception("Export: cannot select active workbook")
    ws.title = f"Week Preferences"
    ws.page_setup.orientation = ws.ORIENTATION_LANDSCAPE
    ws.page_setup.paperSize = ws.PAPERSIZE_A3
    ws.page_setup.fitToHeight = 0
    ws.page_setup.fitToWidth = 1

    # Header titles  
    days = [f"{datetime.strptime(f"{year} {week} {x}", "%G %V %u").strftime("%A")} {datetime.strptime(f"{year} {week} {x}", "%G %V %u").day}" for x in range(1,8)]
    headers = ["Week", "Student", "Course", *days, "Notes", "Cell.", "Mail"]

    # Header fields positions
    week_index: int = headers.index("Week") + 1
    student_index: int = headers.index("Student") + 1
    course_index: int = headers.index("Course") + 1
    cell_index: int = headers.index("Cell.") + 1
    mail_index: int = headers.index("Mail") + 1
    note_index: int = headers.index("Notes") + 1
    
    # Stile header
    header_fill = PatternFill("solid", fgColor="0e005c")
    bold_white = Font(color="FFFFFF", bold=True)
    bold_black = Font(color="000000", bold=True)
    center = Alignment(horizontal="center", vertical="center", wrapText=True)

    # Cell styles 
    border_thick: Side = Side(style='thick', color='000000')
    border_bottom: Border = Border(bottom=border_thick)
    border_left: Border = Border(left=border_thick)
    border_right: Border = Border(right=border_thick)
    border_all: Border = Border(bottom=border_thick, top=border_thick, left=border_thick, right=None)

    # Scrittura header
    for col, h in enumerate(headers, start=1):
        cell = ws.cell(row=1, column=col, value=h)
        cell.fill = header_fill
        cell.font = bold_white
        cell.alignment = center

    ### Start of Student Loop ###
    # Fill worksheet with EVERY training and hb for every student
    # Each of this iterations fills the table for a student
    row: int = 2
    row_offset: int = 0
    for i, q in enumerate(queryset.order_by("student__surname", "student__name", "student__course"), start=1):
        student_data: List[str]
        student_phone: str = q.student.phone if q.student.phone else ""
        student_email: str = q.student.email
        if q.student.course:
            student_data = [f"{q.student.surname} {q.student.name}", f"{q.student.course.ctype}-{q.student.course.cnumber}"]
        else:
            student_data = [f"{q.student.surname} {q.student.name}", f"No Course Assigned"]

        # Fill Training mission rows
        mission_name: str
        mission_days: List[str]
        mission_notes: str
        mission_data: List[List[str]] = []
        for t in Training.objects.filter(weekpref = q.id):
            if not t.mission:
                raise Exception("No Training Mission Assigned")
            mission_name = f"{t.mission.mtype}-{t.mission.mnum}"
            mission_days = [
                mission_name if t.monday else "",
                mission_name if t.tuesday else "",
                mission_name if t.wednesday else "",
                mission_name if t.thursday else "",
                mission_name if t.friday else "",
                mission_name if t.saturday else "",
                mission_name if t.sunday else ""
            ]
            mission_notes = t.notes if t.notes else "--"
            mission_data.append([str(q.week), *student_data, *mission_days, mission_notes, student_phone, student_email, ])

        # Fill HourBuilding rows
        hb_name: str
        hb_days: List[str]
        hb_data: List[List[str]] = []
        for h in HourBuilding.objects.filter(weekpref = q.id):
            hb_name = f"HB-{h.aircraft}\nVedi Note ->"
            hb_days = [
                hb_name if h.monday else "",
                hb_name if h.tuesday else "",
                hb_name if h.wednesday else "",
                hb_name if h.thursday else "",
                hb_name if h.friday else "",
                hb_name if h.saturday else "",
                hb_name if h.sunday else ""
            ]
            hb_notes: List[str] = [f"{h.notes}", "---"] if h.notes else []
            hb_legs_all = HourBuildingLegBase.objects.filter(hb_id = h.id)
            for hh in hb_legs_all:
                if isinstance(hh, HourBuildingLegFlight):
                    hb_notes.append(f"{hh.departure} -> {hh.destination} [{hh.time}]")
                elif isinstance(hh, HourBuildingLegStop):
                    hb_notes.append(f"STOP [{hh.time}] {"Refuel" if hh.refuel else ""}" )
            hb_data.append([str(q.week), *student_data, *hb_days, "\n".join(hb_notes), str(q.student.phone), q.student.email])
         
        # Build rows for table
        all_data: List[List[str]] = mission_data + hb_data
        student_start: int = row + row_offset
        for r in all_data:
            for j, c in enumerate(r, start=1):
                cell = ws.cell(row = row + row_offset, column = j, value = c)
                cell.alignment = center
                # Format Student Name
                if j == student_index:
                    cell.font = bold_black
                # Format Course Column
                if j == course_index and q.student.course:
                    cell.font = bold_black
                    cell.fill = PatternFill("solid", fgColor=str(q.student.course.color).lstrip('#').lower())
            
            prev_cell_val: str = r[0]
            merge_start: bool = False
            merge_col_start: int = 1
            for c, v in enumerate(r, start=1):
                # Merge cells in the row
                if v == prev_cell_val and not merge_start:
                    merge_start = True
                    merge_col_start = c-1 # start merge from previous column
                elif v != prev_cell_val and merge_start:
                    merge_start = False
                    ws.merge_cells(start_row=row+row_offset, 
                                    end_row=row+row_offset, 
                                    start_column=max(merge_col_start,1),
                                    end_column=max(c-1,1)) # end merge to previous column
                prev_cell_val = v
            
            # Incement row counter
            row_offset += 1
        
        # End week preferences for this student
        student_end: int = row + row_offset -1

        # Add thick border to the last cell row of this student
        for i in range(course_index, len(all_data[0])+1):
            ws.cell(row=student_end, column=i).border = border_bottom
            if i == len(all_data[0]):
                for j in range(student_start, student_end + 1):
                    ws.cell(row=j, column=i).border += border_right

        # Merge Week, thick border
        #ws.cell(row=student_start, column=week_index).border = border_bottom
        #ws.merge_cells(start_row=student_start, end_row=student_end, start_column=week_index, end_column=week_index)
        # Merge Name, thick border
        ws.cell(row=student_start, column=student_index).border = border_all
        ws.merge_cells(start_row=student_start, end_row=student_end, start_column=student_index, end_column=student_index)
        # Merge Course
        ws.merge_cells(start_row=student_start, end_row=student_end, start_column=course_index, end_column=course_index)
        # Merge Cell
        ws.merge_cells(start_row=student_start, end_row=student_end, start_column=cell_index, end_column=cell_index)
        # Merge Mail
        ws.merge_cells(start_row=student_start, end_row=student_end, start_column=mail_index, end_column=mail_index)

        # Keep the largest column 
        for column_cells in ws.columns:
            length: int = max(len(str(cell.value)) for cell in column_cells)
            col_letter: str = "A"
            if column_cells[0].column:
                col_letter = get_column_letter(column_cells[0].column)
            ws.column_dimensions[col_letter].width = length + 2
        
        ### End of Student Loop ###


    # Save document in HttpResponse
    wb.save(response)

    return response