"""
HR app admin configuration.
"""

from django.contrib import admin
from django.utils.html import format_html
from django.urls import reverse
from django.utils.safestring import mark_safe
from django.db.models import Count, Avg, Sum
from decimal import Decimal
from datetime import date, timedelta
from .models import *


# ============================================================================
# INLINE ADMIN CLASSES
# ============================================================================

class ScheduleInline(admin.TabularInline):
    """
    Inline admin for employee schedules.
    """
    model = Schedule
    extra = 0
    fields = [
        'name', 'schedule_type', 'effective_date',
        'end_date', 'is_active'
    ]
    readonly_fields = ['schedule_id']


class TimeEntryInline(admin.TabularInline):
    """
    Inline admin for employee time entries.
    """
    model = TimeEntry
    extra = 0
    fields = [
        'work_date', 'clock_in_time', 'clock_out_time',
        'total_hours', 'entry_type', 'status'
    ]
    readonly_fields = ['entry_id', 'total_hours']


class PerformanceReviewInline(admin.TabularInline):
    """
    Inline admin for employee performance reviews.
    """
    model = PerformanceReview
    extra = 0
    fields = [
        'review_date', 'review_type', 'overall_rating', 'status'
    ]
    readonly_fields = ['review_id']


class TrainingRecordInline(admin.TabularInline):
    """
    Inline admin for employee training records.
    """
    model = TrainingRecord
    extra = 0
    fields = [
        'program', 'session', 'completion_date',
        'status', 'passed'
    ]
    readonly_fields = ['record_id']


class ProgramModuleInline(admin.TabularInline):
    """
    Inline admin for training program modules.
    """
    model = ProgramModule
    extra = 0
    fields = ['order', 'title', 'hours']
    ordering = ['order']


class ProgramPrerequisiteInline(admin.TabularInline):
    """
    Inline admin for training program prerequisites.
    """
    model = ProgramPrerequisite
    extra = 0
    fk_name = 'program'
    fields = ['required_program']


class TrainingSessionInline(admin.TabularInline):
    """
    Inline admin for training sessions.
    """
    model = TrainingSession
    extra = 0
    fields = [
        'title', 'start_at', 'end_at', 'instructor',
        'delivery_method', 'capacity'
    ]
    readonly_fields = ['session_id']


class TrainingAttendanceInline(admin.TabularInline):
    """
    Inline admin for training attendance.
    """
    model = TrainingAttendance
    extra = 0
    fields = [
        'checked_in_at', 'checked_out_at', 'status', 'notes'
    ]


class TrainingAssessmentInline(admin.TabularInline):
    """
    Inline admin for training assessments.
    """
    model = TrainingAssessment
    extra = 0
    fields = [
        'name', 'max_score', 'score', 'passed', 'taken_at'
    ]


@admin.register(Employee)
class EmployeeAdmin(admin.ModelAdmin):
    """
    Admin interface for employees.
    """
    list_display = [
        'employee_id', 'get_full_name', 'job_title',
        'department', 'employment_type', 'employment_status',
        'hire_date', 'years_of_service_display', 'license_status_display'
    ]
    list_filter = [
        'tenant', 'department', 'employment_type', 'employment_status',
        'gender', 'hire_date'
    ]
    search_fields = [
        'employee_id', 'first_name', 'last_name',
        'email', 'job_title'
    ]
    readonly_fields = [
        'age', 'years_of_service',
        'is_license_expired',
        'created_at', 'updated_at'
    ]
    fieldsets = [
        ('Employee Information', {
            'fields': [
                 'tenant', 'user'
            ]
        }),
        ('Personal Information', {
            'fields': [
                'first_name', 'father_name', 'grandfather_name', 'last_name',
            ]
        }),
        ('Contact Information', {
            'fields': [
                'email', 'phone', 'mobile_phone', 'profile_picture'
            ]
        }),
        ('Address Information', {
            'fields': [
                'address_line_1', 'address_line_2', 'city', 'postal_code', 'country'
            ],
            'classes': ['collapse']
        }),
        ('Personal Details', {
            'fields': [
                'date_of_birth', 'gender', 'marital_status'
            ]
        }),
        ('Employment Information', {
            'fields': [
                'department', 'job_title', 'employment_type', 'employment_status'
            ]
        }),
        ('Employment Dates', {
            'fields': [
                'hire_date', 'termination_date'
            ]
        }),
        ('Supervisor Information', {
            'fields': [
                'supervisor'
            ]
        }),
        ('Work Schedule Information', {
            'fields': [
                'standard_hours_per_week', 'fte_percentage'
            ]
        }),
        ('Compensation Information', {
            'fields': [
                'hourly_rate', 'annual_salary'
            ]
        }),
        ('Professional Information', {
            'fields': [
                'license_number', 'license_expiry_date',
            ]
        }),
        ('Emergency Contact', {
            'fields': [
                'emergency_contact_name', 'emergency_contact_relationship',
                'emergency_contact_phone'
            ],
            'classes': ['collapse']
        }),
        ('Calculated Fields', {
            'fields': [
                'age', 'years_of_service', 'is_license_expired',
            ],
            'classes': ['collapse']
        }),
        ('Notes', {
            'fields': [
                'notes'
            ],
            'classes': ['collapse']
        }),
        ('Metadata', {
            'fields': [
                'created_at', 'updated_at', 'created_by'
            ],
            'classes': ['collapse']
        })
    ]
    inlines = [ScheduleInline, TimeEntryInline, PerformanceReviewInline, TrainingRecordInline]
    date_hierarchy = 'hire_date'

    def years_of_service_display(self, obj):
        """Display years of service."""
        years = obj.years_of_service
        if years:
            return f"{years:.1f} years"
        return "0 years"
    years_of_service_display.short_description = 'Years of Service'

    def license_status_display(self, obj):
        """Display license status with color coding."""
        if not obj.license_number:
            return format_html('<span style="color: gray;">No License</span>')

        if obj.is_license_expired:
            return format_html('<span style="color: red;">⚠️ Expired</span>')

        if obj.license_expiry_date:
            days_to_expiry = (obj.license_expiry_date - date.today()).days
            if days_to_expiry <= 30:
                return format_html('<span style="color: orange;">⚠️ Expires Soon</span>')

        return format_html('<span style="color: green;">✓ Valid</span>')
    license_status_display.short_description = 'License Status'

    def get_queryset(self, request):
        """Filter by user's tenant."""
        qs = super().get_queryset(request)
        if hasattr(request.user, 'tenant'):
            qs = qs.filter(tenant=request.user.tenant)
        return qs.select_related('department', 'supervisor')


@admin.register(Department)
class DepartmentAdmin(admin.ModelAdmin):
    """
    Admin interface for departments.
    """
    list_display = [
        'code', 'name', 'department_type',
        'department_head', 'employee_count_display',
        'total_fte_display', 'is_active'
    ]
    list_filter = [
        'tenant', 'department_type', 'is_active'
    ]
    search_fields = [
        'code', 'name', 'description'
    ]
    readonly_fields = [
        'department_id', 'employee_count', 'total_fte',
        'created_at', 'updated_at'
    ]
    fieldsets = [
        ('Department Information', {
            'fields': [
                'department_id', 'tenant', 'code', 'name', 'description'
            ]
        }),
        ('Department Type', {
            'fields': [
                'department_type'
            ]
        }),
        ('Hierarchy', {
            'fields': [
                'parent_department'
            ]
        }),
        ('Management', {
            'fields': [
                'department_head'
            ]
        }),
        ('Budget Information', {
            'fields': [
                'annual_budget', 'cost_center'
            ]
        }),
        ('Location Information', {
            'fields': [
                'location'
            ]
        }),
        ('Department Status', {
            'fields': [
                'is_active'
            ]
        }),
        ('Summary Information', {
            'fields': [
                'employee_count', 'total_fte'
            ],
            'classes': ['collapse']
        }),
        ('Notes', {
            'fields': [
                'notes'
            ],
            'classes': ['collapse']
        }),
        ('Metadata', {
            'fields': [
                'created_at', 'updated_at', 'created_by'
            ],
            'classes': ['collapse']
        })
    ]

    def employee_count_display(self, obj):
        """Display employee count."""
        return obj.employee_count
    employee_count_display.short_description = 'Employees'

    def total_fte_display(self, obj):
        """Display total FTE."""
        return f"{obj.total_fte:.1f}"
    total_fte_display.short_description = 'Total FTE'

    def get_queryset(self, request):
        """Filter by user's tenant."""
        qs = super().get_queryset(request)
        if hasattr(request.user, 'tenant'):
            qs = qs.filter(tenant=request.user.tenant)
        return qs.select_related('department_head')


class ScheduleAssignmentInline(admin.TabularInline):
    """
    Inline admin for schedule assignments.
    """
    model = ScheduleAssignment
    extra = 0
    fields = [
        'assignment_date', 'start_time', 'end_time',
        'shift_type', 'status'
    ]
    readonly_fields = ['assignment_id', 'total_hours']


@admin.register(Schedule)
class ScheduleAdmin(admin.ModelAdmin):
    """
    Admin interface for schedules.
    """
    list_display = [
        'employee_name', 'name', 'schedule_type',
        'effective_date', 'end_date', 'is_current_display', 'is_active'
    ]
    list_filter = [
        'schedule_type', 'effective_date', 'is_active'
    ]
    search_fields = [
        'employee__first_name', 'employee__last_name',
        'employee__employee_id', 'name'
    ]
    readonly_fields = [
        'schedule_id', 'tenant', 'is_current',
        'created_at', 'updated_at'
    ]
    fieldsets = [
        ('Schedule Information', {
            'fields': [
                'schedule_id', 'employee', 'name', 'description'
            ]
        }),
        ('Schedule Type', {
            'fields': [
                'schedule_type'
            ]
        }),
        ('Schedule Dates', {
            'fields': [
                'effective_date', 'end_date'
            ]
        }),
        ('Schedule Pattern', {
            'fields': [
                'schedule_pattern'
            ]
        }),
        ('Schedule Status', {
            'fields': [
                'is_active'
            ]
        }),
        ('Approval Information', {
            'fields': [
                'approved_by', 'approval_date'
            ]
        }),
        ('Status Information', {
            'fields': [
                'is_current'
            ],
            'classes': ['collapse']
        }),
        ('Notes', {
            'fields': [
                'notes'
            ],
            'classes': ['collapse']
        }),
        ('Related Information', {
            'fields': [
                'tenant'
            ],
            'classes': ['collapse']
        }),
        ('Metadata', {
            'fields': [
                'created_at', 'updated_at', 'created_by'
            ],
            'classes': ['collapse']
        })
    ]
    inlines = [ScheduleAssignmentInline]
    date_hierarchy = 'effective_date'

    def employee_name(self, obj):
        """Display employee name."""
        return obj.employee.get_full_name()
    employee_name.short_description = 'Employee'

    def is_current_display(self, obj):
        """Display current status with icon."""
        if obj.is_current:
            return format_html('<span style="color: green;">✓ Current</span>')
        return format_html('<span style="color: gray;">Not Current</span>')
    is_current_display.short_description = 'Current'

    def get_queryset(self, request):
        """Filter by user's tenant."""
        qs = super().get_queryset(request)
        if hasattr(request.user, 'tenant'):
            qs = qs.filter(employee__tenant=request.user.tenant)
        return qs.select_related('employee', 'approved_by')


@admin.register(ScheduleAssignment)
class ScheduleAssignmentAdmin(admin.ModelAdmin):
    """
    Admin interface for schedule assignments.
    """
    list_display = [
        'employee_name', 'assignment_date', 'start_time',
        'end_time', 'shift_type', 'total_hours_display', 'status'
    ]
    list_filter = [
        'shift_type', 'status', 'assignment_date'
    ]
    search_fields = [
        'schedule__employee__first_name', 'schedule__employee__last_name',
        'schedule__employee__employee_id'
    ]
    readonly_fields = [
        'assignment_id', 'tenant', 'employee', 'total_hours',
        'created_at', 'updated_at'
    ]
    fieldsets = [
        ('Assignment Information', {
            'fields': [
                'assignment_id', 'schedule'
            ]
        }),
        ('Date and Time', {
            'fields': [
                'assignment_date', 'start_time', 'end_time'
            ]
        }),
        ('Shift Information', {
            'fields': [
                'shift_type'
            ]
        }),
        ('Location Information', {
            'fields': [
                'department', 'location'
            ]
        }),
        ('Assignment Status', {
            'fields': [
                'status'
            ]
        }),
        ('Break Information', {
            'fields': [
                'break_minutes', 'lunch_minutes'
            ]
        }),
        ('Calculated Information', {
            'fields': [
                'total_hours'
            ],
            'classes': ['collapse']
        }),
        ('Notes', {
            'fields': [
                'notes'
            ],
            'classes': ['collapse']
        }),
        ('Related Information', {
            'fields': [
                'tenant', 'employee'
            ],
            'classes': ['collapse']
        }),
        ('Metadata', {
            'fields': [
                'created_at', 'updated_at'
            ],
            'classes': ['collapse']
        })
    ]
    date_hierarchy = 'assignment_date'

    def employee_name(self, obj):
        """Display employee name."""
        return obj.employee.get_full_name()
    employee_name.short_description = 'Employee'

    def total_hours_display(self, obj):
        """Display total hours."""
        return f"{obj.total_hours:.2f}"
    total_hours_display.short_description = 'Hours'

    def get_queryset(self, request):
        """Filter by user's tenant."""
        qs = super().get_queryset(request)
        if hasattr(request.user, 'tenant'):
            qs = qs.filter(schedule__employee__tenant=request.user.tenant)
        return qs.select_related('schedule__employee', 'department')


@admin.register(TimeEntry)
class TimeEntryAdmin(admin.ModelAdmin):
    """
    Admin interface for time entries.
    """
    list_display = [
        'employee_name', 'work_date', 'clock_in_time',
        'clock_out_time', 'total_hours', 'entry_type',
        'status', 'approval_status_display'
    ]
    list_filter = [
        'entry_type', 'status', 'work_date'
    ]
    search_fields = [
        'employee__first_name', 'employee__last_name',
        'employee__employee_id'
    ]
    readonly_fields = [
        'entry_id', 'tenant', 'regular_hours', 'overtime_hours',
        'total_hours', 'is_approved', 'created_at', 'updated_at'
    ]
    fieldsets = [
        ('Time Entry Information', {
            'fields': [
                'entry_id', 'employee'
            ]
        }),
        ('Date and Time', {
            'fields': [
                'work_date', 'clock_in_time', 'clock_out_time'
            ]
        }),
        ('Break Times', {
            'fields': [
                'break_start_time', 'break_end_time',
                'lunch_start_time', 'lunch_end_time'
            ]
        }),
        ('Hours Information', {
            'fields': [
                'regular_hours', 'overtime_hours', 'total_hours'
            ]
        }),
        ('Entry Type', {
            'fields': [
                'entry_type'
            ]
        }),
        ('Department and Location', {
            'fields': [
                'department', 'location'
            ]
        }),
        ('Approval Information', {
            'fields': [
                'approved_by', 'approval_date'
            ]
        }),
        ('Entry Status', {
            'fields': [
                'status'
            ]
        }),
        ('Status Information', {
            'fields': [
                'is_approved'
            ],
            'classes': ['collapse']
        }),
        ('Notes', {
            'fields': [
                'notes'
            ],
            'classes': ['collapse']
        }),
        ('Related Information', {
            'fields': [
                'tenant'
            ],
            'classes': ['collapse']
        }),
        ('Metadata', {
            'fields': [
                'created_at', 'updated_at'
            ],
            'classes': ['collapse']
        })
    ]
    date_hierarchy = 'work_date'

    def employee_name(self, obj):
        """Display employee name."""
        return obj.employee.get_full_name()
    employee_name.short_description = 'Employee'

    def approval_status_display(self, obj):
        """Display approval status with icon."""
        if obj.is_approved:
            return format_html('<span style="color: green;">✓ Approved</span>')
        elif obj.status == 'REJECTED':
            return format_html('<span style="color: red;">✗ Rejected</span>')
        elif obj.status == 'SUBMITTED':
            return format_html('<span style="color: orange;">⏳ Pending</span>')
        return format_html('<span style="color: gray;">Draft</span>')
    approval_status_display.short_description = 'Approval'

    def get_queryset(self, request):
        """Filter by user's tenant."""
        qs = super().get_queryset(request)
        if hasattr(request.user, 'tenant'):
            qs = qs.filter(employee__tenant=request.user.tenant)
        return qs.select_related('employee', 'department', 'approved_by')


@admin.register(PerformanceReview)
class PerformanceReviewAdmin(admin.ModelAdmin):
    """
    Admin interface for performance reviews.
    """
    list_display = [
        'employee_name', 'review_date', 'review_type',
        'overall_rating', 'status', 'is_overdue_display'
    ]
    list_filter = [
        'review_type', 'status', 'overall_rating', 'review_date'
    ]
    search_fields = [
        'employee__first_name', 'employee__last_name',
    ]
    readonly_fields = [
        'review_id', 'is_overdue',
        'created_at', 'updated_at'
    ]
    fieldsets = [
        ('Review Information', {
            'fields': [
                'review_id', 'employee'
            ]
        }),
        ('Review Period', {
            'fields': [
                'review_period_start', 'review_period_end', 'review_date'
            ]
        }),
        ('Review Type', {
            'fields': [
                'review_type'
            ]
        }),
        ('Reviewer Information', {
            'fields': [
                'reviewer'
            ]
        }),
        ('Overall Rating', {
            'fields': [
                'overall_rating'
            ]
        }),
        ('Competency Ratings', {
            'fields': [
                'competency_ratings'
            ]
        }),
        ('Goals and Objectives', {
            'fields': [
                'goals_achieved', 'goals_not_achieved', 'future_goals'
            ]
        }),
        ('Strengths and Areas for Improvement', {
            'fields': [
                'strengths', 'areas_for_improvement'
            ]
        }),
        ('Development Plan', {
            'fields': [
                'development_plan', 'training_recommendations'
            ]
        }),
        ('Employee Comments', {
            'fields': [
                'employee_comments', 'employee_signature_date'
            ]
        }),
        ('Review Status', {
            'fields': [
                'status'
            ]
        }),
        ('Status Information', {
            'fields': [
                'is_overdue'
            ],
            'classes': ['collapse']
        }),
        ('Notes', {
            'fields': [
                'notes'
            ],
            'classes': ['collapse']
        }),
        ('Related Information', {
            'fields': [
                'tenant'
            ],
            'classes': ['collapse']
        }),
        ('Metadata', {
            'fields': [
                'created_at', 'updated_at'
            ],
            'classes': ['collapse']
        })
    ]
    date_hierarchy = 'review_date'

    def employee_name(self, obj):
        """Display employee name."""
        return obj.employee.get_full_name()
    employee_name.short_description = 'Employee'

    def is_overdue_display(self, obj):
        """Display overdue status with icon."""
        if obj.is_overdue:
            return format_html('<span style="color: red;">⚠️ Overdue</span>')
        return format_html('<span style="color: green;">✓ On Time</span>')
    is_overdue_display.short_description = 'Status'

    def get_queryset(self, request):
        """Filter by user's tenant."""
        qs = super().get_queryset(request)
        if hasattr(request.user, 'tenant'):
            qs = qs.filter(employee__tenant=request.user.tenant)
        return qs.select_related('employee', 'reviewer')


# ============================================================================
# TRAINING ADMIN CLASSES
# ============================================================================

@admin.register(TrainingPrograms)
class TrainingProgramsAdmin(admin.ModelAdmin):
    """
    Admin interface for training programs.
    """
    list_display = [
        'name', 'program_type', 'program_provider', 'instructor',
        'duration_hours', 'cost', 'is_certified', 'validity_display'
    ]
    list_filter = [
        'tenant', 'program_type', 'is_certified', 'program_provider'
    ]
    search_fields = [
        'name', 'description', 'program_provider'
    ]
    readonly_fields = [
        'program_id', 'created_at', 'updated_at'
    ]
    fieldsets = [
        ('Program Information', {
            'fields': [
                'program_id', 'tenant', 'name', 'description'
            ]
        }),
        ('Program Details', {
            'fields': [
                'program_type', 'program_provider', 'instructor'
            ]
        }),
        ('Schedule Information', {
            'fields': [
                'start_date', 'end_date', 'duration_hours'
            ]
        }),
        ('Cost Information', {
            'fields': [
                'cost'
            ]
        }),
        ('Certification Information', {
            'fields': [
                'is_certified', 'validity_days', 'notify_before_days'
            ]
        }),
        ('Metadata', {
            'fields': [
                'created_at', 'updated_at', 'created_by'
            ],
            'classes': ['collapse']
        })
    ]
    inlines = [ProgramModuleInline, ProgramPrerequisiteInline, TrainingSessionInline]
    date_hierarchy = 'start_date'

    def validity_display(self, obj):
        """Display validity information."""
        if obj.is_certified and obj.validity_days:
            return f"{obj.validity_days} days"
        return "No expiry"
    validity_display.short_description = 'Validity'

    def get_queryset(self, request):
        """Filter by user's tenant."""
        qs = super().get_queryset(request)
        if hasattr(request.user, 'tenant'):
            qs = qs.filter(tenant=request.user.tenant)
        return qs.select_related('instructor', 'created_by')


@admin.register(ProgramModule)
class ProgramModuleAdmin(admin.ModelAdmin):
    """
    Admin interface for program modules.
    """
    list_display = [
        'program', 'order', 'title', 'hours'
    ]
    list_filter = [
        'program__tenant', 'program'
    ]
    search_fields = [
        'title', 'program__name'
    ]
    ordering = ['program', 'order']

    def get_queryset(self, request):
        """Filter by user's tenant."""
        qs = super().get_queryset(request)
        if hasattr(request.user, 'tenant'):
            qs = qs.filter(program__tenant=request.user.tenant)
        return qs.select_related('program')


@admin.register(ProgramPrerequisite)
class ProgramPrerequisiteAdmin(admin.ModelAdmin):
    """
    Admin interface for program prerequisites.
    """
    list_display = [
        'program', 'required_program'
    ]
    list_filter = [
        'program__tenant', 'program'
    ]
    search_fields = [
        'program__name', 'required_program__name'
    ]

    def get_queryset(self, request):
        """Filter by user's tenant."""
        qs = super().get_queryset(request)
        if hasattr(request.user, 'tenant'):
            qs = qs.filter(program__tenant=request.user.tenant)
        return qs.select_related('program', 'required_program')


@admin.register(TrainingSession)
class TrainingSessionAdmin(admin.ModelAdmin):
    """
    Admin interface for training sessions.
    """
    list_display = [
        'program', 'title_display', 'instructor', 'start_at',
        'end_at', 'delivery_method', 'capacity', 'enrollment_count'
    ]
    list_filter = [
        'program__tenant', 'delivery_method', 'start_at'
    ]
    search_fields = [
        'title', 'program__name', 'instructor__first_name', 'instructor__last_name'
    ]
    readonly_fields = [
        'session_id', 'enrollment_count', 'created_at'
    ]
    fieldsets = [
        ('Session Information', {
            'fields': [
                'session_id', 'program', 'title'
            ]
        }),
        ('Instructor Information', {
            'fields': [
                'instructor'
            ]
        }),
        ('Schedule Information', {
            'fields': [
                'start_at', 'end_at'
            ]
        }),
        ('Delivery Information', {
            'fields': [
                'delivery_method', 'location'
            ]
        }),
        ('Capacity Information', {
            'fields': [
                'capacity', 'enrollment_count'
            ]
        }),
        ('Cost Override', {
            'fields': [
                'cost_override', 'hours_override'
            ]
        }),
        ('Metadata', {
            'fields': [
                'created_at', 'created_by'
            ],
            'classes': ['collapse']
        })
    ]
    date_hierarchy = 'start_at'

    def title_display(self, obj):
        """Display session title or program name."""
        return obj.title or obj.program.name
    title_display.short_description = 'Title'

    def enrollment_count(self, obj):
        """Display enrollment count."""
        return obj.enrollments.count()
    enrollment_count.short_description = 'Enrollments'

    def get_queryset(self, request):
        """Filter by user's tenant."""
        qs = super().get_queryset(request)
        if hasattr(request.user, 'tenant'):
            qs = qs.filter(program__tenant=request.user.tenant)
        return qs.select_related('program', 'instructor', 'created_by')


@admin.register(TrainingRecord)
class TrainingRecordAdmin(admin.ModelAdmin):
    """
    Admin interface for training records (enrollments).
    """
    list_display = [
        'employee_name', 'program', 'session', 'enrolled_at',
        'completion_date', 'status', 'passed', 'expiry_status_display'
    ]
    list_filter = [
        'employee__tenant', 'status', 'passed', 'program__program_type',
        'enrolled_at', 'completion_date'
    ]
    search_fields = [
        'employee__first_name', 'employee__last_name',
        'employee__employee_id', 'program__name'
    ]
    readonly_fields = [
        'record_id', 'enrolled_at', 'hours', 'effective_cost',
        'eligible_for_certificate', 'completion_percentage',
        'created_at', 'updated_at'
    ]
    fieldsets = [
        ('Enrollment Information', {
            'fields': [
                'record_id', 'employee', 'program', 'session'
            ]
        }),
        ('Enrollment Dates', {
            'fields': [
                'enrolled_at', 'started_at', 'completion_date', 'expiry_date'
            ]
        }),
        ('Status Information', {
            'fields': [
                'status', 'passed'
            ]
        }),
        ('Performance Information', {
            'fields': [
                'credits_earned', 'score'
            ]
        }),
        ('Cost Information', {
            'fields': [
                'cost_paid', 'effective_cost'
            ]
        }),
        ('Calculated Information', {
            'fields': [
                'hours', 'eligible_for_certificate', 'completion_percentage'
            ],
            'classes': ['collapse']
        }),
        ('Notes', {
            'fields': [
                'notes'
            ],
            'classes': ['collapse']
        }),
        ('Metadata', {
            'fields': [
                'created_at', 'updated_at', 'created_by'
            ],
            'classes': ['collapse']
        })
    ]
    inlines = [TrainingAttendanceInline, TrainingAssessmentInline]
    date_hierarchy = 'enrolled_at'

    def employee_name(self, obj):
        """Display employee name."""
        return obj.employee.get_full_name()
    employee_name.short_description = 'Employee'

    def expiry_status_display(self, obj):
        """Display expiry status with color coding."""
        if not obj.expiry_date:
            return format_html('<span style="color: gray;">No Expiry</span>')

        days_to_expiry = (obj.expiry_date - date.today()).days
        if days_to_expiry < 0:
            return format_html('<span style="color: red;">⚠️ Expired</span>')
        elif days_to_expiry <= 30:
            return format_html('<span style="color: orange;">⚠️ Expires Soon</span>')
        else:
            return format_html('<span style="color: green;">✓ Valid</span>')
    expiry_status_display.short_description = 'Expiry Status'

    def get_queryset(self, request):
        """Filter by user's tenant."""
        qs = super().get_queryset(request)
        if hasattr(request.user, 'tenant'):
            qs = qs.filter(employee__tenant=request.user.tenant)
        return qs.select_related('employee', 'program', 'session', 'created_by')


@admin.register(TrainingAttendance)
class TrainingAttendanceAdmin(admin.ModelAdmin):
    """
    Admin interface for training attendance.
    """
    list_display = [
        'employee_name', 'program_name', 'checked_in_at',
        'checked_out_at', 'status', 'duration_display'
    ]
    list_filter = [
        'enrollment__employee__tenant', 'status', 'checked_in_at'
    ]
    search_fields = [
        'enrollment__employee__first_name', 'enrollment__employee__last_name',
        'enrollment__program__name'
    ]
    readonly_fields = [
        'duration_display'
    ]
    fieldsets = [
        ('Attendance Information', {
            'fields': [
                'enrollment'
            ]
        }),
        ('Check-in/out Times', {
            'fields': [
                'checked_in_at', 'checked_out_at'
            ]
        }),
        ('Status Information', {
            'fields': [
                'status'
            ]
        }),
        ('Duration Information', {
            'fields': [
                'duration_display'
            ],
            'classes': ['collapse']
        }),
        ('Notes', {
            'fields': [
                'notes'
            ],
            'classes': ['collapse']
        })
    ]
    date_hierarchy = 'checked_in_at'

    def employee_name(self, obj):
        """Display employee name."""
        return obj.enrollment.employee.get_full_name()
    employee_name.short_description = 'Employee'

    def program_name(self, obj):
        """Display program name."""
        return obj.enrollment.program.name
    program_name.short_description = 'Program'

    def duration_display(self, obj):
        """Display attendance duration."""
        if obj.checked_in_at and obj.checked_out_at:
            duration = obj.checked_out_at - obj.checked_in_at
            hours = duration.total_seconds() / 3600
            return f"{hours:.2f} hours"
        return "Incomplete"
    duration_display.short_description = 'Duration'

    def get_queryset(self, request):
        """Filter by user's tenant."""
        qs = super().get_queryset(request)
        if hasattr(request.user, 'tenant'):
            qs = qs.filter(enrollment__employee__tenant=request.user.tenant)
        return qs.select_related('enrollment__employee', 'enrollment__program')


@admin.register(TrainingAssessment)
class TrainingAssessmentAdmin(admin.ModelAdmin):
    """
    Admin interface for training assessments.
    """
    list_display = [
        'employee_name', 'program_name', 'name',
        'score', 'max_score', 'percentage_display', 'passed', 'taken_at'
    ]
    list_filter = [
        'enrollment__employee__tenant', 'passed', 'taken_at'
    ]
    search_fields = [
        'enrollment__employee__first_name', 'enrollment__employee__last_name',
        'enrollment__program__name', 'name'
    ]
    readonly_fields = [
        'percentage_display'
    ]
    fieldsets = [
        ('Assessment Information', {
            'fields': [
                'enrollment', 'name'
            ]
        }),
        ('Score Information', {
            'fields': [
                'max_score', 'score', 'percentage_display', 'passed'
            ]
        }),
        ('Date Information', {
            'fields': [
                'taken_at'
            ]
        }),
        ('Notes', {
            'fields': [
                'notes'
            ],
            'classes': ['collapse']
        })
    ]
    date_hierarchy = 'taken_at'

    def employee_name(self, obj):
        """Display employee name."""
        return obj.enrollment.employee.get_full_name()
    employee_name.short_description = 'Employee'

    def program_name(self, obj):
        """Display program name."""
        return obj.enrollment.program.name
    program_name.short_description = 'Program'

    def percentage_display(self, obj):
        """Display score percentage."""
        if obj.score is not None and obj.max_score > 0:
            percentage = (obj.score / obj.max_score) * 100
            color = 'green' if percentage >= 70 else 'orange' if percentage >= 50 else 'red'
            return format_html(
                '<span style="color: {};">{:.1f}%</span>',
                color, percentage
            )
        return "N/A"
    percentage_display.short_description = 'Percentage'

    def get_queryset(self, request):
        """Filter by user's tenant."""
        qs = super().get_queryset(request)
        if hasattr(request.user, 'tenant'):
            qs = qs.filter(enrollment__employee__tenant=request.user.tenant)
        return qs.select_related('enrollment__employee', 'enrollment__program')


@admin.register(TrainingCertificates)
class TrainingCertificatesAdmin(admin.ModelAdmin):
    """
    Admin interface for training certificates.
    """
    list_display = [
        'employee_name', 'certificate_name', 'program',
        'issued_date', 'expiry_date', 'expiry_status_display',
        'certificate_number'
    ]
    list_filter = [
        'employee__tenant', 'program', 'issued_date', 'expiry_date'
    ]
    search_fields = [
        'employee__first_name', 'employee__last_name',
        'certificate_name', 'certificate_number', 'program__name'
    ]
    readonly_fields = [
        'certificate_id', 'is_expired', 'days_to_expiry',
        'created_at', 'updated_at'
    ]
    fieldsets = [
        ('Certificate Information', {
            'fields': [
                'certificate_id', 'employee', 'program', 'enrollment'
            ]
        }),
        ('Certificate Details', {
            'fields': [
                'certificate_name', 'certificate_number', 'certification_body'
            ]
        }),
        ('Date Information', {
            'fields': [
                'issued_date', 'expiry_date'
            ]
        }),
        ('File Information', {
            'fields': [
                'file'
            ]
        }),
        ('Signature Information', {
            'fields': [
                'created_by', 'signed_by'
            ]
        }),
        ('Status Information', {
            'fields': [
                'is_expired', 'days_to_expiry'
            ],
            'classes': ['collapse']
        }),
        ('Metadata', {
            'fields': [
                'created_at', 'updated_at'
            ],
            'classes': ['collapse']
        })
    ]
    date_hierarchy = 'issued_date'

    def employee_name(self, obj):
        """Display employee name."""
        return obj.employee.get_full_name()
    employee_name.short_description = 'Employee'

    def expiry_status_display(self, obj):
        """Display expiry status with color coding."""
        if not obj.expiry_date:
            return format_html('<span style="color: gray;">No Expiry</span>')

        if obj.is_expired:
            return format_html('<span style="color: red;">⚠️ Expired</span>')

        if obj.days_to_expiry is not None and obj.days_to_expiry <= 30:
            return format_html('<span style="color: orange;">⚠️ Expires Soon</span>')

        return format_html('<span style="color: green;">✓ Valid</span>')
    expiry_status_display.short_description = 'Expiry Status'

    def get_queryset(self, request):
        """Filter by user's tenant."""
        qs = super().get_queryset(request)
        if hasattr(request.user, 'tenant'):
            qs = qs.filter(employee__tenant=request.user.tenant)
        return qs.select_related('employee', 'program', 'enrollment', 'created_by', 'signed_by')


# ============================================================================
# CUSTOM ADMIN ACTIONS
# ============================================================================

def mark_training_completed(modeladmin, request, queryset):
    """Mark selected training records as completed."""
    updated = queryset.update(status='COMPLETED', completion_date=date.today())
    modeladmin.message_user(request, f'{updated} training records marked as completed.')
mark_training_completed.short_description = "Mark selected training as completed"

def mark_training_passed(modeladmin, request, queryset):
    """Mark selected training records as passed."""
    updated = queryset.update(passed=True)
    modeladmin.message_user(request, f'{updated} training records marked as passed.')
mark_training_passed.short_description = "Mark selected training as passed"

def generate_certificates(modeladmin, request, queryset):
    """Generate certificates for completed training."""
    count = 0
    for record in queryset.filter(status='COMPLETED', passed=True):
        if record.program.is_certified and not hasattr(record, 'certificate'):
            TrainingCertificates.objects.create(
                program=record.program,
                employee=record.employee,
                enrollment=record,
                certificate_name=f"{record.program.name} Certificate",
                expiry_date=TrainingCertificates.compute_expiry(record.program, date.today()),
                created_by=request.user
            )
            count += 1
    modeladmin.message_user(request, f'{count} certificates generated.')
generate_certificates.short_description = "Generate certificates for completed training"

# Add actions to TrainingRecord admin
TrainingRecordAdmin.actions = [mark_training_completed, mark_training_passed, generate_certificates]


# ============================================================================
# ADMIN SITE CUSTOMIZATION
# ============================================================================

# Customize admin site
admin.site.site_header = "Hospital Management System - HR"
admin.site.site_title = "HR Admin"
admin.site.index_title = "Human Resources Administration"