import { Input } from '@/Components/ui/input';
import { Label } from '@/Components/ui/label';
import { Textarea } from '@/Components/ui/textarea';
import { Card, CardContent, CardHeader, CardTitle } from '@/Components/ui/card';
import {
    Select, SelectContent, SelectItem, SelectTrigger, SelectValue,
} from '@/Components/ui/select';
import { Button } from '@/Components/ui/button';
import { ChevronDown, ChevronUp, Building2, Search, CheckCircle2 } from 'lucide-react';
import { Dialog, DialogContent, DialogHeader, DialogTitle, DialogTrigger, DialogFooter } from '@/Components/ui/dialog';
import { Avatar, AvatarFallback, AvatarImage } from '@/Components/ui/avatar';
import { Badge } from '@/Components/ui/badge';
import { useEffect, useMemo, useState } from 'react';

const MAIN_CONTRACTOR = 'Great SwissMetal Builders Corporation';

interface Employee { 
    id: number; 
    ulid: string; 
    name: string; 
    email?: string;
    profile_picture?: string | null;
    employee_profile?: {
        department?: string;
        position?: string;
        phone?: string;
    };
}

function ProjectManagerLookup({ employees, selectedId, onSelect, disabled }: { employees: Employee[], selectedId: string, onSelect: (id: string) => void, disabled?: boolean }) {
    const [open, setOpen] = useState(false);
    const [search, setSearch] = useState('');
    const [tempSelectedId, setTempSelectedId] = useState(selectedId);

    const filteredEmployees = useMemo(() => {
        if (!search) return employees;
        const lowerSearch = search.toLowerCase();
        return employees.filter(e => 
            e.name.toLowerCase().includes(lowerSearch) || 
            (e.email && e.email.toLowerCase().includes(lowerSearch)) ||
            (e.employee_profile?.position && e.employee_profile.position.toLowerCase().includes(lowerSearch))
        );
    }, [employees, search]);

    const handleConfirm = () => {
        onSelect(tempSelectedId);
        setOpen(false);
    };

    const handleOpenChange = (newOpen: boolean) => {
        setOpen(newOpen);
        if (newOpen) {
            setTempSelectedId(selectedId);
            setSearch('');
        }
    };

    const selectedEmployee = employees.find(e => e.ulid === selectedId);

    return (
        <>
            <Button 
                variant="outline" 
                role="combobox" 
                onClick={() => !disabled && handleOpenChange(true)}
                className={`w-full justify-between font-normal ${!selectedId ? 'text-muted-foreground' : ''}`}
                disabled={disabled}
            >
                {selectedEmployee ? (
                    <div className="flex items-center gap-2 truncate">
                        <Avatar className="h-6 w-6">
                            {selectedEmployee.profile_picture && (
                                <AvatarImage src={selectedEmployee.profile_picture} alt={selectedEmployee.name} className="object-cover" />
                            )}
                            <AvatarFallback className="text-[10px]">{selectedEmployee.name.substring(0,2).toUpperCase()}</AvatarFallback>
                        </Avatar>
                        <span className="truncate">{selectedEmployee.name}</span>
                        {selectedEmployee.employee_profile?.position && (
                            <span className="text-xs text-muted-foreground hidden sm:inline-block truncate">
                                - {selectedEmployee.employee_profile.position}
                            </span>
                        )}
                    </div>
                ) : (
                    "Select Project Manager"
                )}
                <ChevronDown className="h-4 w-4 shrink-0 opacity-50" />
            </Button>
            <Dialog open={open} onOpenChange={handleOpenChange}>
                <DialogContent className="sm:max-w-2xl max-h-[85vh] flex flex-col p-0 gap-0">
                    <DialogHeader className="px-6 py-4 border-b">
                        <DialogTitle className="text-base font-semibold">Select Project Manager</DialogTitle>
                    </DialogHeader>
                    
                    <div className="px-6 py-3 border-b bg-muted/20">
                        <div className="relative">
                            <Search className="absolute left-3 top-1/2 -translate-y-1/2 h-4 w-4 text-muted-foreground" />
                            <Input
                                placeholder="Search by name, email, or position..."
                                value={search}
                                onChange={(e) => setSearch(e.target.value)}
                                className="pl-9 bg-background text-sm h-9"
                            />
                        </div>
                    </div>

                    <div className="flex-1 overflow-y-auto p-4 max-h-[420px]">
                        {filteredEmployees.length === 0 ? (
                            <div className="text-center py-8 text-sm text-muted-foreground">
                                No project managers found matching your search.
                            </div>
                        ) : (
                            <div className="grid grid-cols-1 sm:grid-cols-2 gap-3">
                                {filteredEmployees.map((emp) => {
                                    const isSelected = tempSelectedId === emp.ulid;
                                    return (
                                        <div
                                            key={emp.ulid}
                                            onClick={() => setTempSelectedId(emp.ulid)}
                                            className={`flex items-center gap-3 p-3 rounded-lg border cursor-pointer transition-all ${
                                                isSelected 
                                                ? 'border-primary bg-primary/5 ring-1 ring-primary' 
                                                : 'border-border hover:bg-accent/40'
                                            }`}
                                        >
                                            <Avatar className="h-10 w-10 shrink-0">
                                                {emp.profile_picture && (
                                                    <AvatarImage src={emp.profile_picture} alt={emp.name} className="object-cover" />
                                                )}
                                                <AvatarFallback className="bg-primary/10 text-primary text-xs font-semibold">
                                                    {emp.name.substring(0, 2).toUpperCase()}
                                                </AvatarFallback>
                                            </Avatar>
                                            <div className="flex-1 min-w-0 pr-1">
                                                <div className="flex items-center justify-between gap-1">
                                                    <p className="text-sm font-semibold truncate text-foreground">{emp.name}</p>
                                                    {isSelected && <CheckCircle2 className="h-4 w-4 text-primary shrink-0" />}
                                                </div>
                                                <p className="text-xs text-muted-foreground truncate" title={emp.email}>
                                                    {emp.email || 'No email provided'}
                                                </p>
                                                {emp.employee_profile?.position && (
                                                    <div className="mt-1">
                                                        <span className="inline-block rounded-md bg-muted px-2 py-0.5 text-[11px] font-medium text-muted-foreground truncate max-w-full">
                                                            {emp.employee_profile.position}
                                                        </span>
                                                    </div>
                                                )}
                                            </div>
                                        </div>
                                    );
                                })}
                            </div>
                        )}
                    </div>

                    <DialogFooter className="mx-0 mb-0 px-6 py-4 border-t bg-muted/20">
                        <Button variant="outline" type="button" onClick={() => setOpen(false)}>Cancel</Button>
                        <Button type="button" onClick={handleConfirm} disabled={!tempSelectedId}>Confirm Selection</Button>
                    </DialogFooter>
                </DialogContent>
            </Dialog>
        </>
    );
}

interface ParentProject { 
    id: number; 
    ulid: string; 
    name: string; 
    code: string; 
    project_type?: string;
    parent_project?: { id: number; ulid: string; name: string; code: string } | null;
}

function ParentProjectLookup({ projects, selectedId, onSelect, disabled }: { projects: ParentProject[], selectedId: string, onSelect: (id: string) => void, disabled?: boolean }) {
    const [open, setOpen] = useState(false);
    const [search, setSearch] = useState('');
    const [tempSelectedId, setTempSelectedId] = useState(selectedId);

    const filteredProjects = useMemo(() => {
        if (!search) return projects;
        const lowerSearch = search.toLowerCase();
        return projects.filter(p => 
            p.name.toLowerCase().includes(lowerSearch) || 
            p.code.toLowerCase().includes(lowerSearch)
        );
    }, [projects, search]);

    const handleConfirm = () => {
        onSelect(tempSelectedId);
        setOpen(false);
    };

    const handleOpenChange = (newOpen: boolean) => {
        setOpen(newOpen);
        if (newOpen) {
            setTempSelectedId(selectedId);
            setSearch('');
        }
    };

    const selectedProject = projects.find(p => p.ulid === selectedId);

    return (
        <>
            <Button 
                variant="outline" 
                role="combobox" 
                onClick={() => !disabled && handleOpenChange(true)}
                className={`w-full justify-between font-normal ${!selectedId ? 'text-muted-foreground' : ''}`}
                type="button"
                disabled={disabled}
            >
                {selectedProject ? (
                    <div className="flex items-center gap-2 truncate">
                        <span className="font-semibold text-xs bg-slate-100 text-slate-700 px-1.5 py-0.5 rounded shrink-0">
                            {selectedProject.code}
                        </span>
                        <span className="truncate">{selectedProject.name}</span>
                    </div>
                ) : (
                    "Select Parent Project"
                )}
                <ChevronDown className="h-4 w-4 shrink-0 opacity-50" />
            </Button>
            <Dialog open={open} onOpenChange={handleOpenChange}>
                <DialogContent className="max-w-4xl max-h-[85vh] flex flex-col p-0 gap-0">
                    <DialogHeader className="px-6 py-5 border-b">
                        <DialogTitle>Select Parent Project</DialogTitle>
                    </DialogHeader>
                    
                    <div className="px-6 py-5 border-b bg-muted/30">
                        <div className="relative">
                            <Search className="absolute left-3 top-1/2 -translate-y-1/2 h-4 w-4 text-muted-foreground" />
                            <Input
                                placeholder="Search by project name or code..."
                                value={search}
                                onChange={(e) => setSearch(e.target.value)}
                                className="pl-9 bg-background"
                            />
                        </div>
                    </div>

                    <div className="flex-1 overflow-y-auto p-6 max-h-[500px]">
                        {filteredProjects.length === 0 ? (
                            <div className="text-center py-8 text-muted-foreground">
                                No active projects found matching your search.
                            </div>
                        ) : (
                            <div className="grid grid-cols-1 sm:grid-cols-2 lg:grid-cols-3 gap-4">
                                {filteredProjects.map((proj) => {
                                    const isSelected = tempSelectedId === proj.ulid;
                                    return (
                                        <div
                                            key={proj.ulid}
                                            onClick={() => setTempSelectedId(proj.ulid)}
                                            className={`flex items-start gap-3 p-3 rounded-lg border cursor-pointer transition-colors ${
                                                isSelected 
                                                ? 'border-primary bg-primary/5 ring-1 ring-primary' 
                                                : 'border-border hover:bg-accent/50'
                                            }`}
                                        >
                                            <div className="flex-1 min-w-0">
                                                <div className="flex items-center justify-between gap-1">
                                                    <span className="font-semibold text-xs bg-slate-100 text-slate-700 px-1.5 py-0.5 rounded shrink-0">
                                                        {proj.code}
                                                    </span>
                                                    {isSelected && <CheckCircle2 className="h-4 w-4 text-primary shrink-0" />}
                                                </div>
                                                <p className="text-sm font-medium mt-1 truncate" title={proj.name}>
                                                    {proj.name}
                                                </p>
                                                {proj.project_type === 'extension' && proj.parent_project && (
                                                    <div className="mt-1.5 flex items-center gap-1.5 text-[10px] text-muted-foreground min-w-0">
                                                        <span className="shrink-0 bg-slate-50 border border-slate-200 px-1 py-0.5 rounded font-mono text-[9px]">
                                                            Ext of {proj.parent_project.code}
                                                        </span>
                                                        <span className="truncate" title={proj.parent_project.name}>
                                                            {proj.parent_project.name}
                                                        </span>
                                                    </div>
                                                )}
                                            </div>
                                        </div>
                                    );
                                })}
                            </div>
                        )}
                    </div>

                    <DialogFooter className="mx-0 mb-0 px-6 py-4 border-t bg-muted/20">
                        <Button variant="outline" type="button" onClick={() => setOpen(false)}>Cancel</Button>
                        <Button type="button" onClick={handleConfirm} disabled={!tempSelectedId}>Confirm Selection</Button>
                    </DialogFooter>
                </DialogContent>
            </Dialog>
        </>
    );
}

export interface ProjectFormData {
    name: string;
    client_name: string;
    location: string;
    start_date: string;
    target_end_date: string;
    contract_duration: string;
    // Additional details
    description: string;
    pm_id: string;
    contract_value: string;
    project_type: string;
    parent_project_id: string;
    is_unprofitable: boolean;
}

interface Props {
    data: ProjectFormData;
    setData: <K extends keyof ProjectFormData>(key: K, value: ProjectFormData[K]) => void;
    errors: Partial<Record<keyof ProjectFormData, string>>;
    employees: Employee[];
    projects?: { id: number; ulid: string; name: string; code: string }[];
    isLocked?: boolean;
}

export function ProjectForm({ data, setData, errors, employees, projects = [], isLocked = false }: Props) {
    const [showAdvanced, setShowAdvanced] = useState(true);

    const employeeSelectItems = useMemo(
        () => employees.map(e => ({ value: e.ulid, label: e.name })),
        [employees],
    );

    // Auto-calculate contract duration when both dates are set
    useEffect(() => {
        if (data.start_date && data.target_end_date) {
            const start = new Date(data.start_date);
            const end = new Date(data.target_end_date);
            const diffMs = end.getTime() - start.getTime();
            if (diffMs >= 0) {
                const days = Math.round(diffMs / (1000 * 60 * 60 * 24)) + 1; // inclusive of start & end
                setData('contract_duration', String(days));
            }
        }
    }, [data.start_date, data.target_end_date]);

    const handleProjectTypeChange = (val: string | null) => {
        const typeVal = val || 'standard';
        setData('project_type', typeVal);
        if (typeVal === 'special') {
            setData('is_unprofitable', true);
        } else if (typeVal === 'standard') {
            setData('is_unprofitable', false);
        }
        if (typeVal !== 'extension') {
            setData('parent_project_id', '');
        }
    };

    return (
        <div className="space-y-6">
            {/* Primary Fields — 1.1 to 1.7 */}
            <Card className="border-slate-200/80 shadow-xs overflow-hidden">
                <CardHeader className="bg-slate-50/50 border-b border-slate-100 py-3 px-5">
                    <CardTitle className="text-sm font-bold text-slate-800">Project Core Parameters</CardTitle>
                </CardHeader>
                <CardContent className="space-y-4 p-5">
                    {/* 1.1 Project Name */}
                    <div>
                        <Label htmlFor="name" className="text-xs font-bold text-slate-700 mb-1.5 block">
                            <span className="text-xs text-slate-400 mr-1.5 font-normal">1.1</span>
                            Project Name <span className="text-red-500">*</span>
                        </Label>
                        <Input
                            id="name"
                            value={data.name}
                            onChange={(e) => setData('name', e.target.value)}
                            placeholder="e.g., Construction of FGEN-PPA Access Road"
                            disabled={isLocked}
                            className="h-10 text-sm border-slate-200"
                        />
                        {errors.name && <p className="mt-1 text-xs font-medium text-red-500">{errors.name}</p>}
                    </div>

                    {/* Project Type Selection */}
                    <div className="grid grid-cols-1 md:grid-cols-2 gap-4">
                        <div>
                            <Label htmlFor="project_type" className="text-xs font-bold text-slate-700 mb-1.5 block">Project Classification</Label>
                            <Select
                                value={data.project_type || 'standard'}
                                onValueChange={handleProjectTypeChange}
                                disabled={isLocked}
                            >
                                <SelectTrigger id="project_type" className="h-10 text-sm border-slate-200">
                                    <SelectValue placeholder="Select Project Type">
                                        {data.project_type === 'standard' && "Standard Project"}
                                        {data.project_type === 'special' && "Special Project (Unprofitable Flag)"}
                                        {data.project_type === 'extension' && "Extension Project (Variation Order)"}
                                    </SelectValue>
                                </SelectTrigger>
                                <SelectContent>
                                    <SelectItem value="standard">Standard Project</SelectItem>
                                    <SelectItem value="special">Special Project (Unprofitable Flag)</SelectItem>
                                    <SelectItem value="extension">Extension Project (Variation Order)</SelectItem>
                                </SelectContent>
                            </Select>
                            {errors.project_type && <p className="mt-1 text-xs font-medium text-red-500">{errors.project_type}</p>}
                        </div>

                        {data.project_type === 'extension' && (
                            <div>
                                <Label htmlFor="parent_project_id" className="text-xs font-bold text-slate-700 mb-1.5 block">Parent Project</Label>
                                <div className="mt-1">
                                    <ParentProjectLookup
                                        projects={projects}
                                        selectedId={data.parent_project_id || ''}
                                        onSelect={val => setData('parent_project_id', val || '')}
                                        disabled={isLocked}
                                    />
                                </div>
                                {errors.parent_project_id && <p className="mt-1 text-xs font-medium text-red-500">{errors.parent_project_id}</p>}
                            </div>
                        )}
                    </div>

                    {/* Unprofitable Flag Checkbox */}
                    <div className="flex items-center gap-3 p-3.5 bg-amber-50/40 border border-amber-200/60 rounded-lg">
                        <input
                            type="checkbox"
                            id="is_unprofitable"
                            checked={data.is_unprofitable || false}
                            onChange={e => setData('is_unprofitable', e.target.checked)}
                            className="rounded border-slate-300 text-amber-600 focus:ring-amber-500 h-4 w-4 cursor-pointer"
                            disabled={isLocked}
                        />
                        <div className="flex flex-col">
                            <Label htmlFor="is_unprofitable" className="font-bold text-xs text-amber-900 cursor-pointer">
                                Unprofitable / Loss-Making Project Flag
                            </Label>
                            <span className="text-[11px] text-amber-700/80">
                                Displays budget warning highlights on procurement approval panels and executive dashboards.
                            </span>
                        </div>
                    </div>

                    {/* 1.2 Project Location & 1.3 Client */}
                    <div className="grid grid-cols-1 md:grid-cols-2 gap-4">
                        <div>
                            <Label htmlFor="location" className="text-xs font-bold text-slate-700 mb-1.5 block">
                                <span className="text-xs text-slate-400 mr-1.5 font-normal">1.2</span>
                                Project Location
                            </Label>
                            <Input
                                id="location"
                                value={data.location}
                                onChange={(e) => setData('location', e.target.value)}
                                placeholder="e.g., Bolbok, Batangas City"
                                disabled={isLocked}
                                className="h-10 text-sm border-slate-200"
                            />
                        </div>
                        <div>
                            <Label htmlFor="client_name" className="text-xs font-bold text-slate-700 mb-1.5 block">
                                <span className="text-xs text-slate-400 mr-1.5 font-normal">1.3</span>
                                Client Name
                            </Label>
                            <Input
                                id="client_name"
                                value={data.client_name}
                                onChange={(e) => setData('client_name', e.target.value)}
                                placeholder="e.g., First Gen Corporation"
                                disabled={isLocked}
                                className="h-10 text-sm border-slate-200"
                            />
                        </div>
                    </div>

                    {/* 1.4 Main Contractor — Hard-coded */}
                    <div>
                        <Label className="text-xs font-bold text-slate-700 mb-1.5 block">
                            <span className="text-xs text-slate-400 mr-1.5 font-normal">1.4</span>
                            Main Contractor
                        </Label>
                        <div className="flex items-center gap-2 rounded-lg border border-slate-200 bg-slate-50 px-3.5 py-2.5 text-sm">
                            <Building2 className="h-4 w-4 text-slate-500 shrink-0" />
                            <span className="font-semibold text-slate-800">{MAIN_CONTRACTOR}</span>
                        </div>
                    </div>

                    {/* 1.5 & 1.6 — Start Date / Project Completion */}
                    <div className="grid grid-cols-1 gap-4 sm:grid-cols-2">
                        <div>
                            <Label htmlFor="start_date" className="text-xs font-bold text-slate-700 mb-1.5 block">
                                <span className="text-xs text-slate-400 mr-1.5 font-normal">1.5</span>
                                Target Start Date
                            </Label>
                            <Input
                                id="start_date"
                                type="date"
                                value={data.start_date}
                                onChange={(e) => setData('start_date', e.target.value)}
                                disabled={isLocked}
                                className="h-10 text-sm border-slate-200"
                            />
                        </div>
                        <div>
                            <Label htmlFor="target_end_date" className="text-xs font-bold text-slate-700 mb-1.5 block">
                                <span className="text-xs text-slate-400 mr-1.5 font-normal">1.6</span>
                                Target Completion Date
                            </Label>
                            <Input
                                id="target_end_date"
                                type="date"
                                value={data.target_end_date}
                                onChange={(e) => setData('target_end_date', e.target.value)}
                                disabled={isLocked}
                                className="h-10 text-sm border-slate-200"
                            />
                            {errors.target_end_date && <p className="mt-1 text-xs font-medium text-red-500">{errors.target_end_date}</p>}
                        </div>
                    </div>

                    {/* 1.7 Contract Duration */}
                    <div>
                        <Label htmlFor="contract_duration" className="text-xs font-bold text-slate-700 mb-1.5 block">
                            <span className="text-xs text-slate-400 mr-1.5 font-normal">1.7</span>
                            Contract Duration (Days)
                        </Label>
                        <div className="flex items-center gap-2">
                            <Input
                                id="contract_duration"
                                type="number"
                                min="0"
                                value={data.contract_duration}
                                onChange={(e) => setData('contract_duration', e.target.value)}
                                className="max-w-[160px] h-10 text-sm border-slate-200"
                                placeholder="0"
                                disabled={isLocked}
                            />
                            <span className="text-sm font-medium text-slate-500">calendar days</span>
                        </div>
                    </div>
                </CardContent>
            </Card>

            {/* Additional Project Parameters */}
            <Card className="border-slate-200/80 shadow-xs">
                <CardHeader
                    className="cursor-pointer select-none bg-slate-50/50 py-3.5 px-6 border-b border-slate-100"
                    onClick={() => setShowAdvanced(!showAdvanced)}
                >
                    <div className="flex items-center justify-between">
                        <CardTitle className="text-base font-bold text-slate-800">Additional Project Parameters</CardTitle>
                        <Button variant="ghost" size="icon" type="button" className="h-8 w-8">
                            {showAdvanced
                                ? <ChevronUp className="h-4 w-4 text-slate-500" />
                                : <ChevronDown className="h-4 w-4 text-slate-500" />}
                        </Button>
                    </div>
                </CardHeader>

                {showAdvanced && (
                    <CardContent className="space-y-5 p-6">
                        {/* Description */}
                        <div>
                            <Label htmlFor="description" className="text-xs font-bold text-slate-700 mb-1.5 block">Project Description</Label>
                            <Textarea
                                id="description"
                                value={data.description}
                                onChange={(e) => setData('description', e.target.value)}
                                rows={3}
                                placeholder="Enter detailed project scope and objectives..."
                                disabled={isLocked}
                                className="text-sm border-slate-200"
                            />
                        </div>

                        <div className="grid grid-cols-1 gap-4 sm:grid-cols-2">
                            {/* Project Manager */}
                            <div>
                                <Label className="text-xs font-bold text-slate-700 mb-1.5 block">Assigned Project Manager</Label>
                                <div>
                                    <ProjectManagerLookup 
                                        employees={employees} 
                                        selectedId={data.pm_id} 
                                        onSelect={(v) => setData('pm_id', v)} 
                                        disabled={isLocked}
                                    />
                                </div>
                            </div>

                            {/* Contract Value */}
                            <div>
                                <Label htmlFor="contract_value" className="text-xs font-bold text-slate-700 mb-1.5 block">Contract Value (PHP)</Label>
                                <Input
                                    id="contract_value"
                                    type="number"
                                    step="0.01"
                                    value={data.contract_value}
                                    onChange={(e) => setData('contract_value', e.target.value)}
                                    placeholder="0.00"
                                    disabled={isLocked}
                                    className="h-10 text-sm border-slate-200 font-mono"
                                />
                                {errors.contract_value && <p className="mt-1 text-xs font-medium text-red-500">{errors.contract_value}</p>}
                            </div>
                        </div>
                    </CardContent>
                )}
            </Card>
        </div>
    );
}