"use client";

import { useState, useMemo, useEffect } from "react";
import PropTypes from "prop-types";
import Modal from "./Modal";
import { getModelsByProviderId, PROVIDER_ID_TO_ALIAS } from "@/shared/constants/models";
import { OAUTH_PROVIDERS, APIKEY_PROVIDERS, FREE_TIER_PROVIDERS, isOpenAICompatibleProvider, isAnthropicCompatibleProvider } from "@/shared/constants/providers";

// Provider order: OAuth first, then Free Tier, then API Key (matches dashboard/providers)
const PROVIDER_ORDER = [
  ...Object.keys(OAUTH_PROVIDERS),
  ...Object.keys(FREE_TIER_PROVIDERS),
  ...Object.keys(APIKEY_PROVIDERS),
];

export default function ModelSelectModal({
  isOpen,
  onClose,
  onSelect,
  selectedModel,
  activeProviders = [],
  title = "Select Model",
  modelAliases = {},
}) {
  const [searchQuery, setSearchQuery] = useState("");
  const [combos, setCombos] = useState([]);
  const [providerNodes, setProviderNodes] = useState([]);

  const fetchCombos = async () => {
    try {
      const res = await fetch("/api/combos");
      if (!res.ok) throw new Error(`Failed to fetch combos: ${res.status}`);
      const data = await res.json();
      setCombos(data.combos || []);
    } catch (error) {
      console.error("Error fetching combos:", error);
      setCombos([]);
    }
  };

  useEffect(() => {
    if (isOpen) fetchCombos();
  }, [isOpen]);

  const fetchProviderNodes = async () => {
    try {
      const res = await fetch("/api/provider-nodes");
      if (!res.ok) throw new Error(`Failed to fetch provider nodes: ${res.status}`);
      const data = await res.json();
      setProviderNodes(data.nodes || []);
    } catch (error) {
      console.error("Error fetching provider nodes:", error);
      setProviderNodes([]);
    }
  };

  useEffect(() => {
    if (isOpen) fetchProviderNodes();
  }, [isOpen]);

  const allProviders = useMemo(() => ({ ...OAUTH_PROVIDERS, ...FREE_TIER_PROVIDERS, ...APIKEY_PROVIDERS }), []);

  // Group models by provider with priority order
  const groupedModels = useMemo(() => {
    const groups = {};

    // Get all active provider IDs from connections
    const activeConnectionIds = activeProviders.map(p => p.provider);

    // Only show connected providers (including both standard and custom)
    const providerIdsToShow = new Set([
      ...activeConnectionIds,  // Only connected providers
    ]);

    // Sort by PROVIDER_ORDER
    const sortedProviderIds = [...providerIdsToShow].sort((a, b) => {
      const indexA = PROVIDER_ORDER.indexOf(a);
      const indexB = PROVIDER_ORDER.indexOf(b);
      return (indexA === -1 ? 999 : indexA) - (indexB === -1 ? 999 : indexB);
    });

    sortedProviderIds.forEach((providerId) => {
      const alias = PROVIDER_ID_TO_ALIAS[providerId] || providerId;
      const providerInfo = allProviders[providerId] || { name: providerId, color: "#666" };
      const isCustomProvider = isOpenAICompatibleProvider(providerId) || isAnthropicCompatibleProvider(providerId);

      if (providerInfo.passthroughModels) {
        const aliasModels = Object.entries(modelAliases)
          .filter(([, fullModel]) => fullModel.startsWith(`${alias}/`))
          .map(([aliasName, fullModel]) => ({
            id: fullModel.replace(`${alias}/`, ""),
            name: aliasName,
            value: fullModel,
          }));

        if (aliasModels.length > 0) {
          // Check for custom name from providerNodes (for compatible providers)
          const matchedNode = providerNodes.find(node => node.id === providerId);
          const displayName = matchedNode?.name || providerInfo.name;

          groups[providerId] = {
            name: displayName,
            alias: alias,
            color: providerInfo.color,
            models: aliasModels,
          };
        }
      } else if (isCustomProvider) {
        // Find connection object to get prefix synchronously without waiting for providerNodes fetch
        const connection = activeProviders.find(p => p.provider === providerId);
        const matchedNode = providerNodes.find(node => node.id === providerId);
        const displayName = connection?.name || matchedNode?.name || providerInfo.name;
        const nodePrefix = connection?.providerSpecificData?.prefix || matchedNode?.prefix || providerId;

        // Aliases are stored using the raw providerId as key (e.g. "openai-compatible-chat-<uuid>/glm-4.7"),
        // so we must filter by providerId, not by the display prefix.
        const nodeModels = Object.entries(modelAliases)
          .filter(([, fullModel]) => fullModel.startsWith(`${providerId}/`))
          .map(([aliasName, fullModel]) => ({
            id: fullModel.replace(`${providerId}/`, ""),
            name: aliasName,
            value: `${nodePrefix}/${fullModel.replace(`${providerId}/`, "")}`,
          }));

        // Always show compatible providers that are connected, even with no aliases.
        // When no aliases exist, show a placeholder so users know it's available.
        const modelsToShow = nodeModels.length > 0 ? nodeModels : [{
          id: `__placeholder__${providerId}`,
          name: `${nodePrefix}/model-id`,
          value: `${nodePrefix}/model-id`,
          isPlaceholder: true,
        }];

        groups[providerId] = {
          name: displayName,
          alias: nodePrefix,
          color: providerInfo.color,
          models: modelsToShow,
          isCustom: true,
          hasModels: nodeModels.length > 0,
        };
      } else {
        const hardcodedModels = getModelsByProviderId(providerId);
        const hardcodedIds = new Set(hardcodedModels.map((m) => m.id));

        // Custom models: if no hardcoded models (e.g. openrouter), show all aliases for this provider
        // Otherwise only show aliases where aliasName === modelId ("Add Model" button pattern)
        const hasHardcoded = hardcodedModels.length > 0;
        const customModels = Object.entries(modelAliases)
          .filter(([aliasName, fullModel]) =>
            fullModel.startsWith(`${alias}/`) &&
            (hasHardcoded ? aliasName === fullModel.replace(`${alias}/`, "") : true) &&
            !hardcodedIds.has(fullModel.replace(`${alias}/`, ""))
          )
          .map(([aliasName, fullModel]) => {
            const modelId = fullModel.replace(`${alias}/`, "");
            return { id: modelId, name: aliasName, value: fullModel, isCustom: true };
          });

        const allModels = [
          ...hardcodedModels.map((m) => ({ id: m.id, name: m.name, value: `${alias}/${m.id}` })),
          ...customModels,
        ];

        if (allModels.length > 0) {
          groups[providerId] = {
            name: providerInfo.name,
            alias: alias,
            color: providerInfo.color,
            models: allModels,
          };
        }
      }
    });

    return groups;
  }, [activeProviders, modelAliases, allProviders, providerNodes]);

  // Filter combos by search query
  const filteredCombos = useMemo(() => {
    if (!searchQuery.trim()) return combos;
    const query = searchQuery.toLowerCase();
    return combos.filter(c => c.name.toLowerCase().includes(query));
  }, [combos, searchQuery]);

  // Filter models by search query
  const filteredGroups = useMemo(() => {
    if (!searchQuery.trim()) return groupedModels;

    const query = searchQuery.toLowerCase();
    const filtered = {};

    Object.entries(groupedModels).forEach(([providerId, group]) => {
      const matchedModels = group.models.filter(
        (m) =>
          m.name.toLowerCase().includes(query) ||
          m.id.toLowerCase().includes(query)
      );

      const providerNameMatches = group.name.toLowerCase().includes(query);

      if (matchedModels.length > 0 || providerNameMatches) {
        filtered[providerId] = {
          ...group,
          models: matchedModels,
        };
      }
    });

    return filtered;
  }, [groupedModels, searchQuery]);

  const handleSelect = (model) => {
    onSelect(model);
    onClose();
    setSearchQuery("");
  };

  return (
    <Modal
      isOpen={isOpen}
      onClose={() => {
        onClose();
        setSearchQuery("");
      }}
      title={title}
      size="md"
      className="p-4!"
    >
      {/* Search - compact */}
      <div className="mb-3">
        <div className="relative">
          <span className="material-symbols-outlined absolute left-2.5 top-1/2 -translate-y-1/2 text-text-muted text-[16px]">
            search
          </span>
          <input
            type="text"
            placeholder="Search..."
            value={searchQuery}
            onChange={(e) => setSearchQuery(e.target.value)}
            className="w-full pl-8 pr-3 py-1.5 bg-surface border border-border rounded text-xs focus:outline-none focus:ring-1 focus:ring-primary/50"
          />
        </div>
      </div>

      {/* Models grouped by provider - compact */}
      <div className="max-h-[300px] overflow-y-auto space-y-3">
        {/* Combos section - always first */}
        {filteredCombos.length > 0 && (
          <div>
            <div className="flex items-center gap-1.5 mb-1.5 sticky top-0 bg-surface py-0.5">
              <span className="material-symbols-outlined text-primary text-[14px]">layers</span>
              <span className="text-xs font-medium text-primary">Combos</span>
              <span className="text-[10px] text-text-muted">({filteredCombos.length})</span>
            </div>
            <div className="flex flex-wrap gap-1.5">
              {filteredCombos.map((combo) => {
                const isSelected = selectedModel === combo.name;
                return (
                  <button
                    key={combo.id}
                    onClick={() => handleSelect({ id: combo.name, name: combo.name, value: combo.name })}
                    className={`
                      px-2 py-1 rounded-xl text-xs font-medium transition-all border hover:cursor-pointer
                      ${isSelected
                        ? "bg-primary text-white border-primary"
                        : "bg-surface border-border text-text-main hover:border-primary/50 hover:bg-primary/5"
                      }
                    `}
                  >
                    {combo.name}
                  </button>
                );
              })}
            </div>
          </div>
        )}

        {/* Provider models */}
        {Object.entries(filteredGroups).map(([providerId, group]) => (
          <div key={providerId}>
            {/* Provider header */}
            <div className="flex items-center gap-1.5 mb-1.5 sticky top-0 bg-surface py-0.5">
              <div
                className="w-2 h-2 rounded-full"
                style={{ backgroundColor: group.color }}
              />
              <span className="text-xs font-medium text-primary">
                {group.name}
              </span>
              <span className="text-[10px] text-text-muted">
                ({group.models.length})
              </span>
            </div>

            <div className="flex flex-wrap gap-1.5">
              {group.models.map((model) => {
                const isSelected = selectedModel === model.value;
                const isPlaceholder = model.isPlaceholder;
                return (
                  <button
                    key={model.id}
                    onClick={() => handleSelect(model)}
                    title={isPlaceholder ? "Select to pre-fill, then edit model ID in the input" : undefined}
                    className={`
                      px-2 py-1 rounded-xl text-xs font-medium transition-all border hover:cursor-pointer
                      ${isPlaceholder
                        ? "border-dashed border-border text-text-muted hover:border-primary/50 hover:text-primary bg-surface italic"
                        : isSelected
                          ? "bg-primary text-white border-primary"
                          : "bg-surface border-border text-text-main hover:border-primary/50 hover:bg-primary/5"
                      }
                    `}
                  >
                    {isPlaceholder ? (
                      <span className="flex items-center gap-1">
                        <span className="material-symbols-outlined text-[11px]">edit</span>
                        {model.name}
                      </span>
                    ) : model.isCustom ? (
                      <span className="flex items-center gap-1">
                        {model.name}
                        <span className="text-[9px] opacity-60 font-normal">custom</span>
                      </span>
                    ) : model.name}
                  </button>
                );
              })}
            </div>
          </div>
        ))}

        {Object.keys(filteredGroups).length === 0 && filteredCombos.length === 0 && (
          <div className="text-center py-4 text-text-muted">
            <span className="material-symbols-outlined text-2xl mb-1 block">
              search_off
            </span>
            <p className="text-xs">No models found</p>
          </div>
        )}
      </div>
    </Modal>
  );
}

ModelSelectModal.propTypes = {
  isOpen: PropTypes.bool.isRequired,
  onClose: PropTypes.func.isRequired,
  onSelect: PropTypes.func.isRequired,
  selectedModel: PropTypes.string,
  activeProviders: PropTypes.arrayOf(
    PropTypes.shape({
      provider: PropTypes.string.isRequired,
    })
  ),
  title: PropTypes.string,
  modelAliases: PropTypes.object,
};