import { useState, useEffect, useCallback, useRef } from "react";
import { Download, FolderOpen, HardDrive } from "lucide-react";
import { save } from "@tauri-apps/plugin-dialog";
import { Button } from "../ui/Button";
import { BackupProgress } from "./BackupProgress";
import { useBackupStore } from "../../stores/backupStore";
import { useNotificationStore } from "../../stores/notificationStore";
import { detectPgTools, pgDump, getSchemas } from "../../lib/commands";
import type { PgToolStatus } from "../../lib/types";

interface BackupPageProps {
    connectionId: string;
}

type BackupFormat = "plain" | "custom" | "tar" | "directory";

const PLATFORM_INSTALL_INSTRUCTIONS: Record<string, string> = {
    darwin: "brew install libpq",
    linux: "sudo apt install postgresql-client  # Debian/Ubuntu\nsudo dnf install postgresql  # Fedora\nsudo pacman -S postgresql  # Arch",
    win32: "Download PostgreSQL installer from https://www.postgresql.org/download/windows/ and ensure pg_dump is in your PATH.",
};

function getPlatformInstructions(): string {
    const platform =
        typeof navigator !== "undefined"
            ? navigator.platform.toLowerCase()
            : "";
    if (platform.includes("mac") || platform.includes("darwin"))
        return PLATFORM_INSTALL_INSTRUCTIONS.darwin;
    if (platform.includes("linux")) return PLATFORM_INSTALL_INSTRUCTIONS.linux;
    if (platform.includes("win")) return PLATFORM_INSTALL_INSTRUCTIONS.win32;
    return PLATFORM_INSTALL_INSTRUCTIONS.linux;
}

export function BackupPage({ connectionId }: BackupPageProps) {
    const [format, setFormat] = useState<BackupFormat>("custom");
    const [filePath, setFilePath] = useState("");
    const [schema, setSchema] = useState("");
    const [noOwner, setNoOwner] = useState(true);
    const [toolStatus, setToolStatus] = useState<PgToolStatus | null>(null);
    const [checkingTools, setCheckingTools] = useState(true);
    const [availableSchemas, setAvailableSchemas] = useState<string[]>([]);

    const activeJobId = useBackupStore((s) => s.activeJobId);
    const jobs = useBackupStore((s) => s.jobs);
    const startJob = useBackupStore((s) => s.startJob);
    const notify = useNotificationStore((s) => s.notify);

    const activeJob = jobs.find((j) => j.id === activeJobId);
    const isRunning = activeJob?.status === "running";

    // Track our job ID so we only react to jobs we started
    const pendingJobRef = useRef<string | null>(null);

    // React to job completion/failure via store events
    useEffect(() => {
        if (!pendingJobRef.current || !activeJob) return;
        if (activeJob.id !== pendingJobRef.current) return;

        if (activeJob.status === "completed") {
            notify("Backup completed successfully", "success");
            pendingJobRef.current = null;
        } else if (activeJob.status === "failed") {
            notify(
                `Backup failed: ${activeJob.error_message || "Unknown error"}`,
                "error",
            );
            pendingJobRef.current = null;
        }
    }, [activeJob, notify]);

    useEffect(() => {
        setCheckingTools(true);
        detectPgTools()
            .then((status) => setToolStatus(status))
            .catch(() =>
                setToolStatus({
                    pg_dump_found: false,
                    pg_restore_found: false,
                    pg_dump_version: null,
                    pg_restore_version: null,
                    pg_dump_source: null,
                    pg_restore_source: null,
                }),
            )
            .finally(() => setCheckingTools(false));

        getSchemas(connectionId)
            .then((schemas) => setAvailableSchemas(schemas))
            .catch(() => setAvailableSchemas([]));
    }, [connectionId]);

    const handlePickFile = useCallback(async () => {
        const extensions: Record<BackupFormat, string[]> = {
            plain: ["sql"],
            custom: ["dump", "custom"],
            tar: ["tar"],
            directory: [],
        };
        const picked = await save({
            defaultPath: `backup.${
                format === "custom"
                    ? "dump"
                    : format === "plain"
                      ? "sql"
                      : "tar"
            }`,
            filters: [{ name: "Backup", extensions: extensions[format] }],
        });
        if (picked) setFilePath(picked);
    }, [format]);

    const handleStartBackup = useCallback(async () => {
        if (!filePath) {
            notify("Please select a file path", "error");
            return;
        }
        const jobId = `dump-${Date.now()}`;
        startJob(jobId, "dump");
        pendingJobRef.current = jobId;

        try {
            // pgDump returns the job ID immediately — completion
            // comes via Tauri events handled by the backupStore
            await pgDump(connectionId, {
                format,
                filePath,
                schema: schema || undefined,
                tables: undefined,
                noOwner,
            });
        } catch (e) {
            // If the command itself fails (e.g. connection not found),
            // the event won't fire — handle here
            const msg = e instanceof Error ? e.message : String(e);
            useBackupStore.getState().failJob(jobId, msg);
        }
    }, [filePath, format, schema, noOwner, connectionId, startJob, notify]);

    const toolsMissing = toolStatus && !toolStatus.pg_dump_found;
    const toolsBundled = toolStatus?.pg_dump_source === "bundled";

    return (
        <div className="flex flex-col h-full">
            {/* Toolbar header */}
            <div className="flex items-center gap-2 border-b border-border px-3 py-1.5">
                <HardDrive size={14} className="text-accent" />
                <span className="text-xs font-medium text-text">Backup</span>
                <span className="text-[11px] text-text-muted">
                    Create a database backup via pg_dump
                </span>
            </div>

            {/* Content */}
            <div className="flex-1 overflow-y-auto">
                <div className="max-w-lg mx-auto space-y-6 outline outline-border">
                    {/* Tool check */}
                    {checkingTools && (
                        <div className="glass p-4 text-center">
                            <p className="text-sm text-text-muted">
                                Checking for pg_dump...
                            </p>
                        </div>
                    )}

                    {toolsMissing && !toolsBundled && (
                        <div className="bg-amber-500/10 border border-amber-500/30 rounded-lg px-4 py-4 space-y-2">
                            <p className="text-amber-300 text-sm font-semibold">
                                pg_dump not found
                            </p>
                            <p className="text-amber-200/80 text-xs leading-relaxed">
                                The PostgreSQL client tools are required for
                                backup/restore operations. Install them using:
                            </p>
                            <pre className="text-xs text-amber-100 bg-amber-500/10 rounded-lg p-3 whitespace-pre-wrap font-mono leading-relaxed">
                                {getPlatformInstructions()}
                            </pre>
                        </div>
                    )}

                    {!checkingTools && !toolsMissing && (
                        <>
                            {/* Configuration card */}
                            <div className="p-5 space-y-5">
                                {/* Format */}
                                <div className="space-y-1">
                                    <label className="text-[11px] uppercase tracking-wider text-text-muted font-medium">
                                        Format
                                    </label>
                                    <select
                                        value={format}
                                        onChange={(e) =>
                                            setFormat(
                                                e.target.value as BackupFormat,
                                            )
                                        }
                                        className="w-full rounded-lg bg-surface border border-border px-3 py-2 text-sm text-text focus:outline-none focus:border-accent focus:ring-1 focus:ring-accent/50 transition-colors cursor-pointer"
                                    >
                                        <option value="custom">
                                            Custom Archive
                                        </option>
                                        <option value="plain">Plain SQL</option>
                                        <option value="tar">Tarball</option>
                                        <option value="directory">
                                            Directory
                                        </option>
                                    </select>
                                </div>

                                {/* Output file */}
                                <div className="space-y-1 w-full">
                                    <label className="text-[11px] uppercase tracking-wider text-text-muted font-medium">
                                        Output File
                                    </label>
                                    <div className="flex gap-2">
                                        <input
                                            type="text"
                                            value={filePath}
                                            onChange={(e) =>
                                                setFilePath(e.target.value)
                                            }
                                            placeholder="/path/to/backup.dump"
                                            className="flex-1 px-4 py-2 text-sm text-text placeholder-text-muted/50 border-b border-border focus:border-accent focus:outline-none transition-colors"
                                        />
                                        <button
                                            type="button"
                                            onClick={handlePickFile}
                                            className="flex items-center justify-center w-9 h-9 rounded-lg border border-border bg-surface text-text-muted hover:text-text hover:bg-surface-raised hover:border-border-hover transition-colors cursor-pointer shrink-0"
                                            aria-label="Browse for file"
                                        >
                                            <FolderOpen size={15} />
                                        </button>
                                    </div>
                                </div>

                                {/* Schema (optional) */}
                                <div className="space-y-1">
                                    <label className="text-[11px] uppercase tracking-wider text-text-muted font-medium">
                                        Schema{" "}
                                        <span className="font-normal normal-case tracking-normal">
                                            (optional)
                                        </span>
                                    </label>
                                    <select
                                        value={schema}
                                        onChange={(e) =>
                                            setSchema(e.target.value)
                                        }
                                        className="w-full rounded-lg bg-surface border border-border px-3 py-2 text-sm text-text focus:outline-none focus:border-accent focus:ring-1 focus:ring-accent/50 transition-colors cursor-pointer"
                                    >
                                        <option value="">All schemas</option>
                                        {availableSchemas.map((s) => (
                                            <option key={s} value={s}>
                                                {s}
                                            </option>
                                        ))}
                                    </select>
                                </div>

                                {/* No-owner toggle */}
                                <label className="flex items-center gap-2.5 cursor-pointer group">
                                    <input
                                        type="checkbox"
                                        checked={noOwner}
                                        onChange={(e) =>
                                            setNoOwner(e.target.checked)
                                        }
                                        className="rounded bg-surface border-border accent-accent w-4 h-4 cursor-pointer"
                                    />
                                    <span className="text-sm text-text-muted group-hover:text-text transition-colors">
                                        No Owner{" "}
                                        <code className="text-[11px] text-text-muted/60 bg-surface-raised rounded px-1.5 py-0.5">
                                            --no-owner
                                        </code>
                                    </span>
                                </label>
                            </div>

                            {/* Progress */}
                            {activeJob && (
                                <div className="px-4">
                                    <BackupProgress
                                        progress={activeJob.status === "completed" ? 100 : 50}
                                        jobType="dump"
                                        status={activeJob.status}
                                        errorMessage={activeJob.error_message ?? undefined}
                                    />
                                </div>
                            )}

                            {/* Actions */}
                            <div className="flex justify-end pb-2 pr-2">
                                <Button
                                    onClick={handleStartBackup}
                                    disabled={isRunning || !filePath}
                                >
                                    <Download size={14} className="mr-1.5" />
                                    {isRunning ? "Backing up..." : "Start Backup"}
                                </Button>
                            </div>
                        </>
                    )}
                </div>
            </div>
        </div>
    );
}