import React, { useCallback, useMemo, useRef, useState } from "react";
import { ScrollView, StyleSheet, Text, View } from "react-native";
import useMinuit from "react-native-minuit/src/hooks/useMinuit.js";
import { background, icons } from "../../assets";
import alert from "../../components/Alert";
import AppCheckbox from "../../components/AppCheckbox";
import BorderGradientButton from "../../components/BorderGradientButton";
import GradientButton from "../../components/GradientButton";
import ItemContainer from "../../components/ItemContainer/ItemContainer";
import MusicLandHeader from "../../components/MusicLandHeader";
import Overlay from "../../components/Overlay";
import firebase, { projectsRef } from "../../config/firebase";
import { strings } from "../../constants/strings";
import { isWeb } from "../../hooks/useLayoutType";
import Page from "../../layouts/Page";
import { Routes } from "../../navigation";
import { navigate } from "../../navigation/NavigationService";
import { useUser } from "../../providers/UserDataProvider";
import { Palette, gutters } from "../../styles";
import { FONT_FAMILY } from "../../styles/Fonts";
import {
  formatStructureLabel,
  getPromptLabelForStructure,
  getSegmentMeta,
  normalizeStructureType,
  sanitizeStructureList,
  segmentRequiresLyrics,
} from "../../utils/songStructure";
import { getStageAction } from "../../utils/projectStages";
import CustomInput from "./components/CustomInput";

const RESPONSIBILITY_CHECKBOX_LABEL =
  "Vous êtes responsable du contenu que vous validez et Musicland ne sera en aucun cas tenu responsable du contenu que vous validez.";

const Lyrics = ({ navigation }) => {
  const scrollRef = useRef(null);
  const [containerLayout, setContainerLayout] = useState(null);
  const { setIsLoading } = useMinuit();
  const { selectedProjectId, selectedProject } = useUser();
  const hasExistingMusicDraft = useMemo(() => {
    if (!Array.isArray(selectedProject?.musicUrls)) return false;
    return selectedProject.musicUrls.some(
      (url) => typeof url === "string" && url.trim()
    );
  }, [selectedProject?.musicUrls]);
  const [isFocus, setIsFocus] = useState(null);
  const [itemsContainerLayout, setItemsContainerLayout] = useState([]);
  const [sensitiveContentModal, setSensitiveContentModal] = useState({
    visible: false,
    title: "",
    message: "",
  });
  const [isSensitiveContentAcknowledged, setIsSensitiveContentAcknowledged] =
    useState(false);
  const sensitiveContentResolverRef = useRef(null);

  const closeSensitiveContentModal = useCallback((result) => {
    setSensitiveContentModal((prev) => ({ ...prev, visible: false }));
    setIsSensitiveContentAcknowledged(false);
    if (sensitiveContentResolverRef.current) {
      sensitiveContentResolverRef.current(result);
      sensitiveContentResolverRef.current = null;
    }
  }, []);

  // Effective sources from provider only
  const projectTitle = selectedProject?.title || "";
  const projectLyrics = Array.isArray(selectedProject?.lyrics)
    ? selectedProject.lyrics
    : [];
  const projectConfig = selectedProject?.config || null;
  const projectSelections = selectedProject?.selections || null;
  const projectHasLyrics = !!selectedProject?.hasLyrics;

  const initial = useMemo(() => {
    const title = projectTitle || "";
    const normalizedSections = Array.isArray(projectLyrics)
      ? projectLyrics.map((s) => ({
          type: normalizeStructureType(s?.type),
          lyrics: s?.lyrics || "",
        }))
      : [];
    const targetStructure = Array.isArray(projectConfig?.structure)
      ? sanitizeStructureList(projectConfig.structure)
      : null;

    const structureToUse =
      targetStructure && targetStructure.length
        ? targetStructure
        : normalizedSections.map((s) => s.type);

    if (!structureToUse.length && normalizedSections.length) {
      return { title, sections: normalizedSections };
    }

    const remaining = [...normalizedSections];
    const takeMatching = (type) => {
      const index = remaining.findIndex((s) => s.type === type);
      if (index !== -1) {
        return remaining.splice(index, 1)[0];
      }
      return remaining.shift() || null;
    };

    const sections = structureToUse.map((segmentType) => {
      const normalizedType = normalizeStructureType(segmentType);
      if (!segmentRequiresLyrics(normalizedType)) {
        return { type: normalizedType, lyrics: "" };
      }
      const matched = takeMatching(normalizedType);
      return {
        type: normalizedType,
        lyrics: matched?.lyrics || "",
      };
    });

    const remainingTextual = remaining.filter((item) =>
      segmentRequiresLyrics(item.type)
    );
    sections.push(...remainingTextual);

    return { title, sections };
  }, [projectTitle, projectLyrics, projectConfig]);

  const [titleValue, setTitleValue] = useState(initial.title || "");
  const [sections, setSections] = useState(initial.sections || []);
  const setSectionAt = (index, value) => {
    setSections((prev) => {
      const next = [...prev];
      if (next[index]) next[index] = { ...next[index], lyrics: value };
      return next;
    });
  };

  // Plus d'appel direct à la cloud function ici: on retourne à l'étape précédente
  const regenerate = useCallback(() => {
    navigate(Routes.CreateLyricsWithAi);
  }, []);

  const sanitize = (obj) => {
    if (obj === undefined) return null;
    if (obj === null) return null;
    if (Array.isArray(obj)) return obj.map((v) => sanitize(v));
    if (typeof obj === "object") {
      const out = {};
      Object.keys(obj).forEach((k) => {
        const v = obj[k];
        if (v === undefined) return; // omit undefined
        out[k] = sanitize(v);
      });
      return out;
    }
    return obj;
  };

  const alertMessage = useCallback((title, message) => {
    alert(title, message);
  }, []);

  const confirmSensitiveContent = useCallback((title, message) => {
    return new Promise((resolve) => {
      sensitiveContentResolverRef.current = resolve;
      setSensitiveContentModal({
        visible: true,
        title,
        message,
      });
      setIsSensitiveContentAcknowledged(false);
    });
  }, []);

  const handleSensitiveCancel = useCallback(() => {
    closeSensitiveContentModal(false);
  }, [closeSensitiveContentModal]);

  const handleSensitiveConfirm = useCallback(() => {
    if (!isSensitiveContentAcknowledged) return;
    closeSensitiveContentModal(true);
  }, [closeSensitiveContentModal, isSensitiveContentAcknowledged]);

  const onValidate = useCallback(async () => {
    try {
      await setIsLoading(true);
      const titleTrimmed = (titleValue || "").trim();
      if (!titleTrimmed) {
        alertMessage("Titre manquant", "Veuillez renseigner un titre.");
        return;
      }
      const invalid = (sections || []).some((s) => {
        const type = normalizeStructureType(s?.type);
        if (!segmentRequiresLyrics(type)) return false;
        return !(s?.lyrics || "").trim();
      });
      if (invalid) {
        alertMessage(
          "Champs incomplets",
          "Chaque section doit contenir du texte."
        );
        return;
      }
      const normalizedNewLyrics = (sections || []).map((s) => ({
        type: normalizeStructureType(s?.type),
        lyrics: segmentRequiresLyrics(normalizeStructureType(s?.type))
          ? (s?.lyrics || "").trim()
          : "",
      }));
      const normalizedOldLyrics = Array.isArray(projectLyrics)
        ? projectLyrics.map((s) => ({
            type: normalizeStructureType(s?.type),
            lyrics: (s?.lyrics || "").trim(),
          }))
        : [];
      const sameLength =
        normalizedOldLyrics.length === normalizedNewLyrics.length;
      const isSame =
        sameLength &&
        normalizedOldLyrics.every(
          (s, i) =>
            s.type === normalizedNewLyrics[i]?.type &&
            s.lyrics === normalizedNewLyrics[i]?.lyrics
        );

      // 1) Appel de la Cloud Function de modération avant tout enregistrement
      try {
        const callable = firebase
          .functions()
          .httpsCallable("lyrics-analyseLyricsToxicity");
        const { data } = await callable({
          title: titleTrimmed,
          lyrics: normalizedNewLyrics,
        });

        if (!data?.success) {
          // Blocage dur: afficher le message et ne pas sauvegarder
          if (data?.errorCode === "TOXIC_CONTENT_BLOCKED") {
            const quotes = Array.isArray(data?.result?.excerpts)
              ? data.result.excerpts
                  .slice(0, 3)
                  .map((e) => `• ${e.quote}`)
                  .join("\n")
              : null;
            alertMessage(
              "Contenu interdit",
              [data?.message, quotes].filter(Boolean).join("\n\n")
            );
            return; // stop here
          }
          // Erreur d'analyse: informer et arrêter
          if (data?.errorCode === "ANALYSE_FAILED") {
            alertMessage(
              "Analyse indisponible",
              "Impossible de vérifier la toxicité pour le moment. Réessayez plus tard."
            );
            return;
          }
        }

        // Cas signalé mais non bloquant: demander confirmation
        if (data?.errorCode === "TOXIC_CONTENT_FLAGGED") {
          const quotes = Array.isArray(data?.result?.excerpts)
            ? data.result.excerpts
                .slice(0, 3)
                .map((e) => `• ${e.quote}`)
                .join("\n")
            : null;
          const msg = [data?.message, quotes].filter(Boolean).join("\n\n");

          const proceed = await confirmSensitiveContent(
            "Contenu potentiellement sensible",
            msg
          );
          if (!proceed) return;
        }
      } catch (moderationError) {
        console.log(
          "Moderation call failed",
          moderationError?.message || moderationError
        );
        alertMessage(
          "Analyse indisponible",
          "Impossible de vérifier la toxicité pour le moment. Réessayez plus tard."
        );
        return;
      }

      const baseData = {
        title: titleTrimmed,
        lyrics: normalizedNewLyrics,
        config: sanitize(projectConfig),
        selections: sanitize(projectSelections),
        updatedAt: firebase.firestore.FieldValue.serverTimestamp(),
        hasLyrics: projectHasLyrics,
      };

      const updateData = { ...baseData };
      if (!isSame) {
        updateData.musicUrls = firebase.firestore.FieldValue.delete();
        updateData.musicStatus = firebase.firestore.FieldValue.delete();
      }
      await projectsRef.doc(selectedProjectId).set(updateData, { merge: true });
      const projectForStage = {
        ...selectedProject,
        title: titleTrimmed,
        lyrics: normalizedNewLyrics,
        config: sanitize(projectConfig),
        selections: sanitize(projectSelections),
        hasLyrics: true,
      };
      if (!isSame) {
        projectForStage.musicUrls = undefined;
        projectForStage.musicStatus = undefined;
      }
      const beatmakerStage = getStageAction("beatmaker", projectForStage);
      await setIsLoading(false);
      if (hasExistingMusicDraft) {
        navigate(Routes.ComposeSong, { isRegeneration: true });
        return;
      }
      const handleNavigateToStudio = () => {
        const targetRoute = beatmakerStage?.route || Routes.Compose;
        navigate(targetRoute, beatmakerStage?.params);
      };
      alert(
        "Céline",
        "Bravo ! Vous venez de terminer de créer les paroles de votre musique ! Maintenant vous pouvez passer à la prochaine étape : le Studio pour donner vie à votre chanson !",
        [
          {
            text: "Retour à l'accueil",
            style: "cancel",
            onPress: () =>
              navigate(Routes.BottomTab, {
                screen: Routes.HomeStack,
                params: {
                  screen: Routes.Home,
                },
              }),
          },
          {
            text: "Continuer vers le Studio",
            onPress: handleNavigateToStudio,
          },
        ]
      );
      return;
    } catch (e) {
      console.log(e);
      alertMessage("Erreur", "Échec de l'enregistrement dans le projet.");
    } finally {
      await setIsLoading(false);
    }
  }, [
    titleValue,
    sections,
    projectConfig,
    projectSelections,
    alertMessage,
    confirmSensitiveContent,
    sanitize,
    setIsLoading,
    selectedProjectId,
    projectHasLyrics,
    projectLyrics,
    selectedProject,
    hasExistingMusicDraft,
  ]);

  const typeOccurrences = {};

  return (
    <Page
      backgroundImg={isWeb ? background.libraryBgWeb : background.writingBG}
      headerType="NONE"
    >
      <MusicLandHeader
        onPressBack={() => navigate(Routes.Home)}
        progress={95}
        logo={icons.musicLandWriting}
      />
      <View
        style={{
          flex: 1,
          marginTop: 16,
          gap: 48,
        }}
        onLayout={(e) => setContainerLayout(e.nativeEvent.layout)}
      >
        <ItemContainer
          height={containerLayout?.height}
          disableKeyboardHeight={isFocus !== sections.length - 1 || !isFocus}
        >
          <ScrollView
            ref={scrollRef}
            contentContainerStyle={{
              paddingHorizontal: 14,
              paddingVertical: 10,
              gap: 10,
              flexGrow: 1,
            }}
          >
            <View style={styles.headerContainer}>
              <Text style={styles.headerTitle}>
                {strings.writing.lyrics.title}
              </Text>
              <Text style={styles.instructions}>
                {strings.writing.lyrics.instructions}
              </Text>
              <View style={styles.personalizationBanner}>
                <Text style={styles.personalizationText}>
                  {strings.writing.lyrics.personalizationBanner}
                </Text>
              </View>
            </View>
            <CustomInput
              label="Titre"
              placeholder="Titre"
              height={45}
              value={titleValue}
              setValue={setTitleValue}
              multiline={false}
              maxLength={60}
              onLayout={(e) => {
                e.persist();
                setItemsContainerLayout((prev) => [
                  ...prev,
                  e?.nativeEvent?.layout,
                ]);
              }}
            />
            {sections.map((s, idx) => {
              const normalizedType = normalizeStructureType(s?.type);
              const key = normalizedType || "section";
              typeOccurrences[key] = (typeOccurrences[key] || 0) + 1;
              const occurrence = typeOccurrences[key];
              const label = formatStructureLabel(key, occurrence);
              const meta = getSegmentMeta(key);
              const inputHeight =
                typeof meta?.inputHeight === "number"
                  ? meta.inputHeight
                  : key === "refrain"
                    ? 170
                    : 225;
              const placeholder = meta?.label || label;
              const requiresLyrics = segmentRequiresLyrics(key);
              if (!requiresLyrics) {
                return (
                  <View key={idx} style={styles.instrumentalBlock}>
                    <Text style={styles.instrumentalTitle}>{label}</Text>
                    <Text style={styles.instrumentalText}>
                      {getPromptLabelForStructure(key)} — section instrumentale
                      sans paroles.
                    </Text>
                  </View>
                );
              }
              return (
                <CustomInput
                  key={idx}
                  label={label}
                  placeholder={placeholder}
                  height={inputHeight}
                  value={s?.lyrics || ""}
                  setValue={(val) => setSectionAt(idx, val)}
                  onFocus={() => {
                    setIsFocus(idx);
                    scrollRef?.current?.scrollTo({
                      y: itemsContainerLayout[idx + 1]?.y,
                    });
                  }}
                  onLayout={(e) => {
                    e.persist();
                    setItemsContainerLayout((prev) => [
                      ...prev,
                      e?.nativeEvent?.layout,
                    ]);
                  }}
                />
              );
            })}
          </ScrollView>
        </ItemContainer>
      </View>
      <View
        style={{
          paddingTop: gutters,
          paddingBottom: gutters * 2,
          paddingHorizontal: gutters,
          gap: 12,
        }}
      >
        {!projectHasLyrics && (
          <BorderGradientButton
            title="Générer d'autres paroles"
            onPress={regenerate}
          />
        )}
        <GradientButton title="Valider" onPress={onValidate} />
      </View>
      <Overlay
        isVisible={sensitiveContentModal.visible}
        setIsVisible={(visible) => {
          if (visible === false) {
            handleSensitiveCancel();
          }
        }}
        contentContainerStyle={{
          alignItems: "center",
          justifyContent: "center",
        }}
      >
        <View style={styles.sensitiveModal}>
          <Text style={styles.sensitiveModalTitle}>
            {sensitiveContentModal.title}
          </Text>
          <Text style={styles.sensitiveModalMessage}>
            {sensitiveContentModal.message}
          </Text>
          <View style={styles.sensitiveCheckboxWrapper}>
            <AppCheckbox
              selected={isSensitiveContentAcknowledged}
              onPress={() => setIsSensitiveContentAcknowledged((prev) => !prev)}
              label={RESPONSIBILITY_CHECKBOX_LABEL}
            />
          </View>
          <View style={styles.sensitiveModalActions}>
            <BorderGradientButton
              title="Annuler"
              onPress={handleSensitiveCancel}
              containerStyle={{ flex: 1 }}
            />
            <GradientButton
              title="Continuer"
              onPress={handleSensitiveConfirm}
              disabled={!isSensitiveContentAcknowledged}
              containerStyle={{ flex: 1 }}
            />
          </View>
        </View>
      </Overlay>
    </Page>
  );
};

export default Lyrics;

const styles = StyleSheet.create({
  headerContainer: {
    gap: 8,
    paddingHorizontal: 2,
  },
  headerTitle: {
    color: Palette.white,
    fontFamily: FONT_FAMILY.InterSemiBold,
    fontSize: 20,
  },
  instructions: {
    color: Palette.white,
    fontFamily: FONT_FAMILY.InterRegular,
    fontSize: 14,
    lineHeight: 20,
  },
  personalizationBanner: {
    backgroundColor: Palette.ultraLightWhite,
    borderRadius: 12,
    paddingVertical: 10,
    paddingHorizontal: 12,
    marginTop: 4,
  },
  personalizationText: {
    color: Palette.white,
    fontFamily: FONT_FAMILY.InterMedium,
    fontSize: 14,
    lineHeight: 20,
  },
  instrumentalBlock: {
    padding: 16,
    borderRadius: 12,
    backgroundColor: Palette.ultraLightWhite,
    gap: 6,
  },
  instrumentalTitle: {
    fontFamily: FONT_FAMILY.InterSemiBold,
    fontSize: 16,
    color: Palette.white,
  },
  instrumentalText: {
    fontFamily: FONT_FAMILY.InterRegular,
    fontSize: 14,
    color: Palette.white,
    opacity: 0.8,
  },
  sensitiveModal: {
    width: "90%",
    maxWidth: 460,
    backgroundColor: Palette.lightPurple,
    borderRadius: 18,
    paddingVertical: 24,
    paddingHorizontal: 20,
    gap: 16,
  },
  sensitiveModalTitle: {
    fontFamily: FONT_FAMILY.InterSemiBold,
    fontSize: 20,
    color: Palette.white,
    textAlign: "center",
  },
  sensitiveModalMessage: {
    fontFamily: FONT_FAMILY.InterRegular,
    fontSize: 15,
    color: Palette.white,
    lineHeight: 20,
    textAlign: "left",
    opacity: 0.9,
  },
  sensitiveCheckboxWrapper: {
    paddingVertical: 4,
  },
  sensitiveModalActions: {
    flexDirection: "row",
    gap: 12,
  },
});